Modern taxonomy has therefore shifted toward an integrative framework that combines morphology, host and tissue specificity, and molecular sequence data, allowing researchers to separate cryptic species that look nearly identical under the microscope. The new study exemplifies this approach, synthesizing evidence from spore morphometrics, histopathology, and ribosomal DNA phylogenetics to establish the new species on firm ground. The survey took place between June and December 2024 in the Zi River near Xinhua County in Loudi City, Hunan Province, an area whose river systems and Dongting Lake support a documented fish fauna of 218 species.

Yet myxosporean surveys in this province remain scarce, with only two prior studies, one conducted in the last century and another covering just twelve fish species. Thirty-four barbel chub specimens, weighing between 316.5 and 498.5 grams, were collected using gill-nets and examined comprehensively upon arrival at the laboratory. Infection was found in 11 of the 34 fish examined, a prevalence of 32.35 percent.

Numerous whitish plasmodia, ellipsoidal in shape and measuring up to 2 millimeters long and 1.5 millimeters wide, were distributed throughout the intestinal wall. No infections were detected in other organs, and despite the extensive plasmodial burden, infected fish showed no abnormal behavior compared with healthy individuals. Upon rupturing the plasmodia, mature myxospores were released and observed.

These spores were round in the valvular view and lenticular in the sutural view, measuring 8.8 micrometers long, 8.3 micrometers wide, and 3.8 micrometers thick on average. Two equal, pyriform polar capsules sat at the anterior end, each containing a polar tubule coiled with four to five turns. The spores lacked a mucous envelope and intercapsular appendix but possessed three to four distinct posterior folds, a combination of traits that distinguishes the new species from its relatives.

Histopathological examination revealed that the plasmodia developed within the circular muscle layer of the host intestine, a tissue site frequently favored by intestinal myxozoans. Expanding plasmodia compressed adjacent muscle fibers and became surrounded by a thin connective tissue capsule, yet the infection elicited no observable inflammatory response. No muscle fiber atrophy, necrosis, mucosal damage, epithelial desquamation, or obstruction of the intestinal lumen was detected.

The pronounced tropism for muscular tissue, while not fully understood, may be linked to the relatively high availability of nutrients and metabolic resources in this tissue, which could favor parasite proliferation. To characterize the parasite molecularly, researchers extracted genomic DNA from ethanol-preserved plasmodia and amplified a partial sequence of the small subunit ribosomal DNA using universal myxosporean primers. The resulting sequence, 1,731 base pairs in length, was deposited in GenBank under accession number PV785691.

Phylogenetic reconstruction based on a dataset of 43 SSU rDNA sequences, rooted with Zschokkella nova as the outgroup, yielded two primary clades, A and B, with highly similar topologies from both Maximum Likelihood and Bayesian Inference methods. Notably, the new species did not cluster with other Myxobolus species known to infect the intestine, such as Myxobolus huasaensis, Myxobolus gayerae, and Myxobolus kiuchowensis. This pattern suggests that intestinal tropism may not provide a strong phylogenetic signal in this group, in contrast to site specificity at organs such as the gills, where species infecting similar tissues often cluster together.

The analysis also revealed structured patterns linking myxozoan evolution to morphology, host phylogeny, and biogeography. Subclade I predominantly comprises species with ellipsoidal myxospores infecting cyprinid and leuciscid hosts in Hungary and Portugal, while Subclade II consists of species with ellipsoidal spores infecting these host families across a broader Holarctic range including Europe and North America. Subclade III, by contrast, is primarily composed of species from China and India infecting cyprinid hosts, exhibiting a mix of spore shapes including ellipsoidal, pyriform, and round forms.

This diversity suggests that spore morphology within this lineage is evolutionarily labile and may have undergone multiple transitions, reinforcing the conclusion that myxozoan evolution is shaped by a combination of ecological, morphological, and biogeographic factors rather than by any single trait. The discovery of Myxobolus curriculus sp. nov. enriches the known myxosporean fauna of Hunan Province and establishes the first record of any myxosporean parasite in barbel chub from this region. The barbel chub, a widely distributed cyprinid of growing aquacultural interest due to its disease resistance, including potential resistance to grass carp hemorrhage disease, had only approximately 11 myxosporean species reported globally before this study.

Subject of Research: Myxozoan parasite taxonomy and biodiversity

Article Title: Morphological and molecular characterizations of Myxobolus curriculus sp. nov. ( Myxozoa , Myxobolidae ) infecting the intestine of Barbel chub Squaliobarbus curriculus in China

Article References: Yuan, S., Liu, X., Geng, X., Liu, W., He, M., Li, D., Xiang, J., & Dai, W. (2026). Morphological and molecular characterizations of Myxobolus curriculus sp. nov. (Myxozoa, Myxobolidae) infecting the intestine of Barbel chub Squaliobarbus curriculus in China. Zoosystematics and Evolution, 102(3), 807-815. https://doi.org/10.3897/zse.102.191790

Image Credits: AI Generated

DOI: 10.3897/zse.102.191790

Keywords: Myxozoa, Myxobolus, parasitology, fish parasites, taxonomy, China, aquaculture, biodiversity, Morphological, molecular, characterizations, curriculus

Chewing lice in the Oxylipeurus-complex are wing lice that parasitise mainly gamefowl, and most species are known from Asian galliforms. For decades, nearly all of these lice were lumped into a single genus, Oxylipeurus, a classification that later researchers challenged repeatedly. Since 2009, a large number of new genus-level taxa have been established within this complex, and the new study adds a third genus described in recent years from the same host group. The new genus, Pelecolipeurus, is separated from other members of the complex by a unique combination of characters, including the distinctive shape of the male subgenital plate and stylus, the structure of the male genitalia, and details of the abdominal sclerites.

The name Pelecolipeurus is derived from the Greek word pélekus, meaning two-headed axe, combined with Lipeurus, the traditional name for long slender lice. The reference is to the shape of the male subgenital plate, which bears lateral extensions at the base of the stylus. The only previously known species in the genus is Lipeurus longus, described by Piaget in 1880, which the authors tentatively re-describe as Pelecolipeurus longus based on specimens from Temminck’s tragopan, Tragopan temminckii. In addition, they describe a new species, Pelecolipeurus fujianensis, based on specimens from Cabot’s tragopan, Tragopan caboti, collected in Fujian Province, China.

Assessing taxon limits in this complex is notoriously difficult. The overall chaetotaxy and morphology, including that of the male genitalia, are conserved in many genera, and species are often delimited by more nebulous characters such as head shape, mesosome shape and the degree of reticulation of the cuticle. Many species are poorly known and have not been fully described or illustrated; the last detailed revisions of the complex were published by Clay in 1938 and von Kéler in 1958. The new study examined slide-mounted specimens deposited at the National Natural History Museum of Natural History, China, using a Nikon Eclipse Ni microscope with a drawing tube attached for making illustrations, and measurements were made in the digital measuring software ImageJ.

The diagnosis of Pelecolipeurus rests on a suite of morphological characters. The frons is rounded to slightly flattened; the dorsal pre-antennal suture is present but transversal, not reaching the lateral margins of the head; the marginal mesometathoracic setae are gathered into a single sublateral bunch; the male tergopleurites II–VII are medianly interrupted and intertergal sclerites are absent; the male tergopleurites IX–XI are fused to form a single plate, while in the female they are fused laterally but not medianly, forming two distinct plates. The male subgenital plate has a unique shape with lateral extensions at the base of the stylus, and the stylus is subterminal and elongated, reaching beyond the distal margin of the abdomen. The female vulval margin is narrowly concave, without lateral accessory vulval plates, and the male genitalia are very long, reaching anteriorly to abdominal segment III, with a denticulate genital sac.

Pelecolipeurus fujianensis can be separated from Pelecolipeurus longus by several characters, including the shape of the male fused abdominal segments IX–XI, which have concave lateral margins in the new species but more or less straight lateral margins in the older species, and the shape of the proximal mesosome, which has a medianly pointed anterior end in the new species but a flattened anterior margin in the older species. The parameres are also more curved in the older species than in the new one. Unfortunately, no specimens from the type host of Pelecolipeurus longus, the satyr tragopan, were found at the Chinese museum, and the lectotype and paratypes at the Natural History Museum in London could not be examined or borrowed. A photo of the lectotype female available online confirms that the species belongs to Pelecolipeurus, but is insufficiently detailed to compare adequately with the specimens examined in China.

Beyond the description of the new genus, the study presents an overview of the distribution patterns of ischnoceran lice on galliforms, and the patterns that emerge are remarkable. Galliforms have some of the most diverse chewing louse faunas of any bird order. In the checklist of Price and colleagues from 2003, lice on galliform hosts represent almost 10 percent of all avian louse genera accepted as valid. If genera accepted by Mey in 2009 and those described from other host groups since 2003 are added, over 23 percent of the known louse genera occur on galliform hosts, despite Galliformes itself comprising only about 2.66 percent of bird diversity. The reasons for this over-diversity are unclear, and the ancient lineage of galliforms, with fossil records going back perhaps to the late Cretaceous, does not by itself explain the pattern, since the closely related anseriforms are only parasitised by a small fraction of louse genera.

The overview reveals a clear division in the Oxylipeurus-complex between genera occurring mainly on New World host groups and those occurring mainly on Old World hosts. With the exception of one species, all members of the genera Chelopistes, Eiconolipeurus, Epicolinus, Labicotes, Trichodomedea and Valimia are found only on New World hosts. In contrast, the genera Megalipeurus, Pelecolipeurus, Calidolipeurus, Cataphractomimus, Gallancyra and Sinolipeurus are only found on Old World hosts. The genera Oxylipeurus and Talegallipeurus are exclusively known in Australia and Wallacea. That leaves only one cosmopolitan genus, Reticulipeurus, which is known both in the Old and New Worlds, and whose distribution on two distinct host groups — mainly Asian phasianids and almost entirely Neotropical cracids — requires further study to understand.

Of particular interest are the lice of the tragopan group, comprising the genera Lophophorus, Tetraophasis and Tragopan, which together form a monophyletic clade with no close relatives. These high-elevation birds are collectively parasitised by at least three genera of Oxylipeurus-complex lice that are so far not known from hosts outside that clade — Cataphractomimus, Pelecolipeurus and Sinolipeurus — as well as a morphologically distinct group of Lagopoecus, four genera within the Goniodes-complex and almost all the known species of Dictyocotes. With the exception of Dictyocotes, all these genera and groups are unique to hosts in the tragopan group. Despite comprising only ten species in three genera, the species in this group are hosts to a considerable diversity of lice, and the relevant factors structuring these host associations appear to be a mixture of host phylogeny and habitat factors, since all the hosts are high-elevation birds.

The study also transfers the genus Afrilipeurus from the Oxylipeurus-complex to the Lipeurus-complex, where it is probably closely related to Numidilipeurus, which occurs on the same host group. This transfer is based on detailed morphological comparisons, including the presence of multiple sternal setae and tergal posterior setae on segments II–VIII, medianly continuous tergopleurites, intertergal plates on male segments III–IV, and numerous vulval oblique setae forming roughly convergent rows — all characters typical of the Lipeurus-complex but absent in the Oxylipeurus-complex. The authors include an emended key to the Oxylipeurus-complex, updating the genus-level key previously published by Gustafsson and colleagues in 2020. Overall, the study suggests that no single factor can be used to explain distribution patterns amongst the Ischnocera that parasitise galliform hosts. Host phylogeny, host biogeography and host ecology all appear to influence the known host associations, and in some cases it is not clear which factors are most important, as several factors overlap. Elevation may also influence distribution patterns, with several distinct genera and groups known only or mainly to infest high-elevation hosts, while low-elevation hosts are often parasitised by more widely distributed louse genera. As more becomes known of the lice of galliform hosts, clearer patterns may emerge that could explain the unexpectedly high diversity of lice on landfowl, and future collections from high-altitude galliforms may help determine the extent to which the three genera of Oxylipeurus-complex lice on Temminck’s tragopan co-occur on the same host population, giving insights into the process of microhabitat partitioning in chewing lice and potentially into the process of higher-level radiation of lice on hosts.

Subject of Research: Description of the new louse genus Pelecolipeurus and an overview of ischnoceran chewing lice on galliform hosts

Article Title: New genus and species of lice in the Oxylipeurus -complex ( Phthiraptera , Ischnocera , Philopteridae ), with an overview of the distribution of ischnoceran chewing lice on galliform hosts

Article References: Gustafsson, D. R., Tian, C., Ren, M., Li, Z., Sun, X., & Zou, F. (2024). New genus and species of lice in the Oxylipeurus-complex (Phthiraptera, Ischnocera, Philopteridae), with an overview of the distribution of ischnoceran chewing lice on galliform hosts. Deutsche Entomologische Zeitschrift, 71(1), 85-109. https://doi.org/10.3897/dez.71.111874

Image Credits: AI Generated

DOI: 10.3897/dez.71.111874

Keywords: chewing lice, Phthiraptera, Ischnocera, galliform birds, taxonomy, parasitology, tragopans, coevolution, genus, species, lice, Oxylipeurus

Researchers from the Parasitology and Medical Malacology Research Unit at Silpakorn University collected 1,175 pulmonate snails between October 2021 and October 2022 from 27 locations in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, and Songkhla provinces. Sampling focused on paddy fields, streams, and irrigation canals, using hand picking and stainless-steel scoops, with each site georeferenced by GPS. The specimens were transported to aerated tanks and identified in the laboratory according to shell morphology using established Thai taxonomic keys.

The conchological analysis revealed three families, five genera, and seven species: Amerianna carinata, Gyraulus bakeri, Gyraulus convexiusculus, Gyraulus hubendicki, Physella acuta, Indoplanorbis exustus, and Radix rubiginosa. Indoplanorbis exustus dominated the haul with 802 individuals collected from 25 of the 27 sites, reflecting its broad distribution across Thailand, India, Sri Lanka, Indonesia, the Philippines, Japan, and Hawaii. Radix rubiginosa, the sole lymnaeid species, appeared at 16 locations, while the remaining species were comparatively rare.

To detect infections, the team used two complementary techniques. In the cercarial shedding method, individual snails were placed in small cups of dechlorinated water and observed twice daily for seven to ten days for the emergence of free-swimming cercariae, the larval stage that leaves the snail to seek its next host. Snails that shed nothing were then crushed to reveal the parthenitae — sporocysts and rediae — and developing cercariae inside. Emergent larvae were examined live and stained with 0.5 percent neutral red under dissecting and light microscopes, photographed with differential interference contrast microscopy, and measured from formalin-fixed specimens.

Eleven snails — an overall infection rate of 0.94 percent — proved positive, and the morphology of their cercariae sorted them into five types and eight species. Echinostome cercariae included Echinoparyphium recurvatum, Echinostoma spiniferum, and Echinostoma revolutum, intestinal flukes recognizable by the collar spines ringing the oral sucker. Brevifurcate-apharyngeate cercariae comprised the blood flukes Schistosoma indicum and S. spindale, fork-tailed larvae lacking a pharynx. A brevifurcate-pharyngeate-clinostomatoid type represented Clinostomum giganticum, a parasite of fish-eating birds; a longifurcate-pharyngeate strigeid type was Diplostomum baeri eucaliae, the eye fluke of fish; and an ophthalmoxiphidiocercaria of the family Allocreadiidae completed the roster.

Only three of the seven snail species carried infections, but the rates differed strikingly. Radix rubiginosa was the most heavily parasitized, with seven of 174 individuals infected — a rate of 4.02 percent — shedding four cercarial types and six species. Gyraulus convexiusculus followed at 1.14 percent, with two of 176 snails releasing Echinoparyphium recurvatum and the ophthalmoxiphidiocercaria. Indoplanorbis exustus, despite its abundance, showed the lowest rate at 0.25 percent, yet its two infections carried the greatest medical weight: one snail shed Schistosoma indicum, the very parasite behind the 2020 dermatitis outbreak, and another released Clinostomum giganticum.

The detailed morphology of each cercaria provided the identification evidence. The schistosome larvae, for example, are elongate-oval bodies with a head organ, five pairs of penetration glands, and a tail longer than the body that forks into two furcae bearing excretory pores at their tips. In S. indicum the penetration glands are stacked sac-like from the ventral sucker to the rear of the body, whereas in S. spindale they line up laterally along the body — a subtle but decisive distinction. The echinostomes, by contrast, develop within rediae and bear collar spines, with species separated by body shape, finfold presence, and the proportions of suckers and pharynx.

Several findings were firsts for Thailand. Natural infections of Echinoparyphium recurvatum and Echinostoma spiniferum in Radix rubiginosa had never been recorded in the country, and although E. recurvatum is a cosmopolitan intestinal fluke of wildfowl and mammals that has infected humans in Taiwan, Indonesia, Korea, and Egypt, no human case has yet been documented in Thailand. The detection of an ophthalmoxiphidiocercaria in Gyraulus convexiusculus was likewise notable, since allocreadiid cercariae are more typically associated with sphaeriid bivalves and lymnaeid snails elsewhere. Meanwhile, finding S. spindale in R. rubiginosa rather than its usual host I. exustus hints that host–parasite relationships in the region may be more flexible than previously assumed.

The veterinary and public health stakes are considerable. Indoplanorbis exustus is the sole intermediate host of the Schistosoma indicum species group, which drives severe outbreaks of cattle schistosomiasis and human cercarial dermatitis across India and Southeast Asia. Clinostomum giganticum, whose metacercariae encyst under the skin of freshwater fish as the yellow grubs of fish-farming lore, can infect people who eat raw or undercooked fish, linking snail control directly to food safety. Diplostomum species cause diplostomatosis, or eye fluke disease, in fish, imposing losses on aquaculture even though they do not infect humans directly.

The authors argue that controlling these snail-borne diseases demands a holistic, ecosystem-level approach rather than a single-target intervention: maintaining water quality, managing snail populations in paddy fields and canals, and limiting bird access to fish habitats where clinostome and diplostome life cycles depend on avian definitive hosts. Cercarial dermatitis disproportionately affects paddy workers, agricultural laborers, and fishermen — the very people whose livelihoods keep them in constant contact with infested water. With comprehensive data on gastropod infections still lacking across much of Southeast Asia, the team calls for expanded surveys in other regions to map the true extent and impact of these hidden parasites, emphasizing that the distribution of snail intermediate hosts plays a decisive role in where trematode transmission will strike next.

Subject of Research: Trematode infections in freshwater pulmonate snails in southern Thailand and their role in cercarial dermatitis transmission

Article Title: Freshwater pulmonate snails and their potential role as trematode intermediate host in a cercarial dermatitis outbreak in Southern Thailand

Article References: Wongpim, T., Komsuwan, J., Janmanee, C., Thongchot, P., Limsampan, S., Wichiannarat, N., Chaowatut, W., Suwanrat, S., Dechruksa, W., Veeravechsukij, N., Glaubrecht, M., & Krailas, D. (2023). Freshwater pulmonate snails and their potential role as trematode intermediate host in a cercarial dermatitis outbreak in Southern Thailand. Evolutionary Systematics, 7(2), 293-315. https://doi.org/10.3897/evolsyst.7.107847

Image Credits: AI Generated

DOI: 10.3897/evolsyst.7.107847

Keywords: cercarial dermatitis, trematodes, pulmonate snails, Schistosoma indicum, Indoplanorbis exustus, Radix rubiginosa, echinostomes, Thailand, intermediate hosts, parasitology, malacology, zoonoses

Horsehair worms, of which roughly 360 species are currently described, lead a double life that reads like science fiction. As juveniles they are internal parasites, hijacking the bodies of insects such as grasshoppers, beetles and praying mantids, along with other arthropods including centipedes and millipedes. Marine species in the genus Nectonema parasitize decapod crustaceans, while the freshwater gordiids, the group to which the new species belongs, target terrestrial and aquatic insects. Once mature, the worms manipulate their hosts to seek water, then burst out as free-living adults to find mates and lay eggs. Adults are typically encountered in lakes, ponds, rivers, streams and even artificial water bodies such as cattle troughs, which makes their repeated appearance on snow in the Hindu Kush, Karakoram and Himalayan ranges all the more remarkable.

The specimens were collected from two districts of Khyber Pakhtunkhwa province. In Dir Upper, thirteen worms were taken from the village of Gat Koto, the type locality at an altitude of about 2,333 meters, and seven more from Shaltaloo, roughly 2.5 kilometers away, during three separate visits in December 2020, December 2021 and March 2024. Four live specimens were later collected from Karang in Upper Kohistan on 10 January 2025. At every locality and on every occasion, the animals were found alive and actively moving on freshly fallen snow in the early morning. Thorough searches of nearby freshwater failed to turn up any worms, and no potential hosts were observed close to the collection sites, deepening the mystery of why the adults emerged onto snow at all.

Identifying horsehair worms to species level is notoriously difficult, and the new study relied on scanning electron microscopy to resolve the fine cuticular details that separate closely related forms. In the genus Gordius, males are recognized by a postcloacal crescent at the posterior end and paired rounded tail lobes, whereas in the only other genus with a crescent, Acutogordius, the tail lobes are pointed. Beyond these features, differences between Gordius species are often minute and their variability is poorly understood, making it hard to distinguish within-species variation from true species differences. Females are even harder to identify because they possess fewer diagnostic characters. The research team, working at the Laboratory of Entomology and Vector-borne Diseases at the University of Peshawar, examined live specimens under a stereomicroscope, preserved males in 70 percent ethanol, and reared females in spring water until their natural death in early March 2022 to check for oviposition.

The electron micrographs revealed the character that sets the Pakistani worms apart from every other known member of the genus: a dense covering of fine spines, or bristles, concentrated in the anterior body region. While several Gordius species carry sparsely distributed short spines on the body cuticle, only two species are known to have bristles in the anterior end. Gordius terrestris from North America has very fine bristles, but it also bears polygonal areoles on the cuticle, a feature absent in the Pakistani specimens. Gordius wulingensis, described from China in 2025, has anterior bristles but in far smaller numbers. The smooth cuticle and the morphology of the male and female posterior ends of the new species otherwise correspond to several other Gordius species, so it is the sheer density of anterior spines that justifies the description as new.

The physical description of the worms follows familiar gordiid proportions. Males measured between 110 and 185 millimeters in length and around one millimeter in width, with a yellowish brown to light brown coloration that darkened after preservation. Living specimens carried light creamy white spots on the cuticle, densest from the anterior to mid-body and becoming scant toward the posterior, along with two creamy dorsal lines prominent in the anterior region. The anterior tip bears a white calotte followed by a dark black collar, and the posterior end carries a semicircular postcloacal crescent and two blunt tail lobes. Females, of which thirteen were examined, measured between 160 and 255 millimeters, shared the same spotting and coloration, and possessed a round posterior end bearing a vase-like cloacal opening at the tip. Some females carried a sperm drop on their posterior end, indicating they had mated before collection.

Laboratory observations added unexpected biological detail. Adult mated females lived for more than two months in spring water at room temperature, with average day and night temperatures of 20 and 5 degrees Celsius from December through February, spanning collections from December 2020 to March 2021 and December 2021 to March 2022. The team also documented the stubborn resistance of the worms’ cuticle to standard clearing techniques: mid-body segments of males mounted in Puri’s gum-chloral medium took a full year to become clear enough for microscopy, while female specimens placed overnight in 10 percent potassium hydroxide, a common clearing agent for insects and arachnids, were largely dissolved, leaving behind only the anterior collar and posterior tip. Ironically, this harsh treatment helped reveal the bristles around the collar that proved so taxonomically decisive.

The association with snow is a genuinely exceptional phenomenon among nematomorphs. Because it was observed repeatedly across multiple localities and years, the researchers believe it is a natural occurrence rather than an anomaly. Yet the life cycle of Gordius nixus remains completely unknown, with no host species found near the worms. In temperate regions, horsehair worm life cycles appear coupled to the seasons: in central Europe, free-living specimens emerge most abundantly in summer and fall, with species-specific time windows of occurrence. Adults die after depositing gametes, and nematomorphs are thought to survive the winter as eggs, larvae or within their intermediate hosts. Occasional records of adult worms during winter and under icy conditions exist, including one from 1913, but such records are rare and considered exceptions. How G. nixus times its emergence, finds partners on snow, and which hosts sustain its larvae are questions that now demand field observation.

The formal description of G. nixus also redraws the biogeographic map of a phylum whose documentation is strikingly uneven. Pakistan had no previously recorded horsehair worm species, and neighboring countries fare little better. Afghanistan has no records at all, Iran has only three, all from the northern region, and India’s 22 known species come mostly from the east, with just three records from the northwest. China reports 17 species from five genera, including six Gordius species, though most are insufficiently well described for in-depth comparison. Beyond the investigated specimens, the authors received confirmed reports of horsehair worms from seven further Pakistani locations, spanning altitudes from about 780 to 1,550 meters, including one sighting from a rice paddy and another from water, suggesting the animals are far more widespread than the formal record indicates.

With parts of the region crisscrossed by streams and rivers that appear well suited for nematomorphs, the researchers expect the true biodiversity of horsehair worms in Pakistan and neighboring regions to be considerably higher than current records suggest. The holotype, allotype and paratypes have been deposited in the Pakistan Museum of Natural History, providing an anchor for future taxonomic work. Whether Gordius nixus proves to be a cold-adapted specialist of high mountain ecosystems or simply the first documented member of a hidden diversity of snow-associated worms, its discovery demonstrates how much remains unknown about parasites in underexplored landscapes, and how even a routine winter walk across fresh snow can yield a species new to science.

Subject of Research: First horsehair worm species described from Pakistan, discovered unusually on snow

Article Title:  Gordius nixus sp. nov.: first report of a horsehair worm ( Gordiida , Nematomorpha ) from snow in Pakistan

Article References: Jamal, Q., Riaz, M., Uddin, M., & Schmidt-Rhaesa, A. (2025). Gordius nixus sp. nov.: first report of a horsehair worm (Gordiida, Nematomorpha) from snow in Pakistan. Evolutionary Systematics, 9(2), 183-189. https://doi.org/10.3897/evolsyst.9.153102

Image Credits: AI Generated

DOI: 10.3897/evolsyst.9.153102

Keywords: Nematomorpha, horsehair worms, parasitology, Pakistan, new species, taxonomy, Hindu Kush, biodiversity, Gordius, nixus, first, report

The research fills a conspicuous gap in the parasitological record of the South Caucasus. Systematic surveys of gastrointestinal helminths in Georgian small mammals were last conducted in the mid-twentieth century by Kirshenblat, Rodonaia, Matsaberidze, and Kurashvili, with only a single recent paper documenting a cestode in the mole-rat Nannospalax xanthodon. The vicinity of Usholta, located within the Oni Municipality at coordinates N42°29’59”, E43°24’07”, sits at the border of forest and subalpine landscape zones and had never been explored for these parasites. The region is faunistically rich, with records of around 42 mammal species, making it an ideal natural laboratory for studying host-parasite relationships in an unexplored highland ecosystem.

The collected hosts included eight specimens of the lesser wood mouse Apodemus uralensis (family Muridae), eight Daghestan voles Microtus daghestanicus (family Cricetidae), and three common weasels Mustela nivalis (family Mustelidae). For each animal, the gastrointestinal tract and related organs were examined for helminths. The researchers calculated standard parasitological indicators, including prevalence, mean intensity of infestation, parasitation range, and mean abundance, following the protocols of Bush et al. (1997), Anikanova et al. (2007), and Dege et al. (2019). Cestodes were washed, fixed in 70-degree alcohol, and rendered transparent with a glycerin-lactic acid mixture before being stained in aceto-carmine and mounted in Canada balsam. Nematodes were similarly fixed and cleared for morphological and morphometric study under a stereomicroscope with dual illumination and a 10-megapixel digital camera. Voucher material is stored in the collection of the Institute of Zoology at Ilia State University.

The results were striking. Five of the eight wood mice carried one or more helminth species, while every single vole and every weasel examined was infected, yielding an overall infection rate of 84.2 percent across all 19 animals. This is remarkable given that the summer of 2022 in Usholta was characterized by unusually low rodent numbers and a limited species composition. Ten helminth species were detected in total: four cestodes and six nematodes. The cestodes included Paranoplocephala omphalodes, Versteria mustelae, larval Echinococcus multilocularis, and Rodentolepis asymmetrica. The nematodes comprised Heligmosomoides polygyrus, Heligmosomum costellatum, Syphacia obvelata, an unidentified Syphacia species, Trichuris muris, and Molineus patens.

The most consequential discovery came from a single wood mouse whose liver harbored approximately 60 larvocysts of Echinococcus multilocularis, each vesicle measuring between 1 and 3 millimeters. This represents a novel host record for the parasite in Georgia, as larvocysts of this species had never been found in the genus Apodemus within the country. The larval stage of Echinococcus differs from the adult strobilar stage in its exceptionally wide distribution and pathogenicity. Mouse-like rodents, particularly voles, typically serve as the main intermediate hosts, and the presence of larvae in a wood mouse is most plausibly explained by local environmental conditions and food sources. Historically, Kurashvili first registered the larval form in the social vole Microtus socialis in Georgia in 1961, and Matsaberidze later found it in the liver of the mountain vole M. roberti across forest, subalpine, and alpine zones of Eastern Georgia. In neighboring Russia, Kirillova and Kirillov documented infestation rates of 1.3 percent in the common vole and 1.2 percent in the field mouse. The Usholta finding allows researchers to predict the spread of this dangerous helminth both among rodent intermediate hosts in the zone and among its final hosts, the Canidae.

Among the nematodes of the wood mouse, Heligmosomoides polygyrus emerged as the dominant species with a prevalence of 3 out of 8 hosts, a parasitation range of 3 to 39 worms, and a mean abundance of 6.75. Trichuris muris appeared in only one mouse with two specimens, giving the lowest mean abundance of 0.25. Syphacia obvelata, by contrast, reached a mean intensity of 66 worms in a single infected host, with 66 specimens recovered from the cecum of one individual and a mean abundance of 8.25. These figures align well with historical data from Matsaberidze, who recorded abundances of 1 to 300 for S. obvelata in rodents across Eastern Georgian vegetation zones. All three nematodes are obligate, widespread parasites of rodents previously documented in different regions of Georgia and in adjacent South Caucasus republics.

The Daghestan vole hosted two cestode species, Paranoplocephala omphalodes and Rodentolepis asymmetrica, with the latter showing a higher prevalence of 3 out of 8 hosts, a range of 1 to 4 worms, and a mean abundance of 0.75. Both are obligate rodent parasites recorded several times in Transcaucasia, and Kirshenblat originally discovered them in the Daghestan vole in the forest zone at 1040 meters above sea level near the village of Ermani. According to Kirillova and Kirillov, infection with adult cestodes such as P. omphalodes occurs through the accidental ingestion, along with grassy food or while digging burrows, of small soil invertebrates, including mites and springtails, which act as intermediate hosts. Because M. daghestanicus is an herbivore feeding on plant parts above the soil, the researchers believe a similar feeding-driven invasion process operates for P. omphalodes at the forest-subalpine border of Usholta. A single vole also carried the nematode Heligmosomum costellatum, and one vole harbored 158 specimens of an unidentified Syphacia species, yielding a mean abundance of 19.75.

The common weasel, Mustela nivalis, a carnivore widely distributed in Georgian forest and subalpine zones up to 3000 meters above sea level, was infected with the cestode Versteria mustelae and the nematodes Molineus patens and Syphacia sp. The presence of Syphacia sp. in the intestinal tract of M. nivalis is a new host record for Georgia. This finding is intriguing because Syphacia nematodes are strict-specific parasites, mostly host-specific at the genus level, and typically parasitize rodents rather than carnivores. The researchers invoke the concept of post-cyclic parasitism, documented by Varodi et al. (2017), in which mustelids acquire diverse rodent nematode communities by preying on infected prey. Molineus patens, by contrast, is a highly specific parasite of Carnivora, widespread in the Mustelidae, and commonly detected in Georgian weasels by Rodonaia in the mid-twentieth century. Versteria mustelae, formerly classified as Taenia tenuicollis, was recorded by Rodonaia in Georgian weasels and classified based on the descriptions of Petrov and Abuladze. Bagnato and colleagues have suggested that all new species of the genus Versteria are potential zoonotics, and the Usholta team similarly considers V. mustelae a possible source of zoonotic invasion in the wild.

Only one wood mouse was simultaneously infected with two nematode species, Syphacia sp. and Trichuris muris, while a single weasel carried three helminth species at once: Versteria mustelae, Molineus patens, and Syphacia sp. Mixed infections of this kind illustrate the complexity of parasite communities within individual hosts and the ecological connections linking carnivores to their rodent prey through shared parasite faunas. The pattern in which mean intensities remained relatively low despite high overall prevalence suggests that the basic conditions for the functioning of the parasite-host system are preserved in this parasitologically unexplored region, agreeing with findings previously obtained in different regions of Georgia by Kirshenblat, Matsaberidze, and Rodonaia.

The formation of the micromammal helminth fauna in Usholta is tied to the local ecosystem, a complex of biotic and abiotic factors including food type, soil-related lifestyle, and the availability of intermediate hosts. Rodents act as definitive, intermediate, and reservoir hosts of helminths and serve as vectors of numerous zoonotic diseases, making primary biodiversity data on these parasites crucially important for preventing parasitic diseases in humans and livestock. The new data from Usholta supplement existing knowledge on helminth biodiversity, expand understanding of their distribution and host specificity in Georgia, and underscore the importance of continued research on wildlife parasites in the Caucasus, a mountainous hotspot where ecosystems are shifting and host-parasite dynamics remain only partially mapped.

Subject of Research: Gastrointestinal helminth diversity and host-parasite relationships in small mammals near Usholta, Georgia

Article Title: Gastrointestinal helminths of small mammals ( Rodentia and Carnivora ) in the vicinity of Usholta, Georgia

Article References: Nikolaishvili, K., Lomidze, T., Arabuli, L., Asatiani, K., & Murvanidze, L. (2024). Gastrointestinal helminths of small mammals (Rodentia and Carnivora) in the vicinity of Usholta, Georgia. Caucasiana, 3, 245-256. https://doi.org/10.3897/caucasiana.3.e132243

Image Credits: AI Generated

DOI: 10.3897/caucasiana.3.e132243

Keywords: parasitology, helminths, Georgia, Echinococcus multilocularis, rodents, Mustela nivalis, zoonoses, Caucasus biodiversity, Gastrointestinal, small, mammals, Rodentia

The study, led by mycologist João Araújo of the New York Botanical Garden and colleagues, focused on the Adolpho Ducke Reserve, a 100-square-kilometer patch of primary rainforest embedded within the city of Manaus. The team surveyed the reserve’s understory, documenting ants that had been killed by Ophiocordyceps and noting exactly where the fungal spore-bearing structures, called ascomata, emerged from the victims’ bodies. They then collected samples of the mosses and liverworts, collectively known as bryophytes, growing at these sites, along with additional bryophyte samples from elsewhere in the reserve.

Back in the laboratory, the researchers used DNA metabarcoding to identify the fungi living within the bryophyte tissues. They amplified a genetic marker called TEF1-alpha and sequenced the resulting DNA using Oxford Nanopore technology, a portable sequencing platform capable of reading long DNA fragments. The analysis revealed a startling diversity of fungal life: across all the bryophyte samples, the team detected 2,677 distinct fungal taxa, spanning a wide range of ecological roles from decomposers to plant pathogens.

Crucially, the most abundant group of fungi detected within the mosses was Ophiocordyceps itself. The researchers found DNA of these zombie-ant fungi in nearly every bryophyte sample, including mosses growing far from any infected ants. The team identified several species known to infect ants in the region, including Ophiocordyceps camponoti-renggeri, Ophiocordyceps kniphofioides, and Ophiocordyceps monacidis, among others. The detection of these species within moss tissues, rather than merely on their surfaces, suggests the fungi were living as endophytes within the plants.

The findings build on years of fieldwork by Araújo and colleagues, who had previously noticed that certain ant-infecting Ophiocordyceps species in the Amazon seemed to preferentially manipulate their victims into biting specific plants before dying. Infected Camponotus ants, for example, were repeatedly found locked in a death grip on moss carpets, particularly those of the moss Octoblepharum, with the fungal ascomata emerging from their bodies. Other species showed similar affinities for bromeliads, palm trees, and other understory plants. These observations hinted that the fungi might have some physiological connection to the plants their victims died on, but the mechanism remained unknown.

The new study provides the first direct evidence that Ophiocordyceps can live within bryophyte tissues in the Amazon. The researchers propose that the fungi may use mosses as a refuge or reservoir, persisting in the environment between ant infections. This hidden endophytic stage could serve several functions: it might allow the fungi to survive unfavorable conditions, such as dry seasons when ant hosts are scarce; it could provide a substrate for the fungi to reproduce sexually, which some species require to complete their life cycle; or it might even play a role in the fungi’s dispersal, with spores or fragments carried away by rain, wind, or animals.

The idea that Ophiocordyceps has a plant-associated stage is not entirely new. Previous studies in Asia had found that the caterpillar fungus Ophiocordyceps sinensis, which infects ghost moth larvae on the Tibetan Plateau, also lives within the tissues of alpine plants. And researchers had detected DNA of Ophiocordyceps within mosses in temperate regions of North America and Europe. But the Amazon study is the first to systematically document this phenomenon in the tropics, where the diversity of both fungi and bryophytes is far greater.

The researchers also note that the endophytic stage may explain some puzzling aspects of the zombie-ant fungi’s ecology. For example, the fungi are known to be highly host-specific, with each species typically infecting only one or a few ant species. Yet the fungi must also find their hosts in a complex, three-dimensional forest environment. If the fungi persist within bryophytes, which form extensive carpets on the forest floor and on tree trunks, they may be able to wait in ambush for passing ants, increasing their chances of infection. The fungi’s preference for certain plants, such as Octoblepharum mosses, may reflect the microhabitat preferences of their ant hosts, which often forage on these substrates.

The study also raises questions about the evolutionary history of the zombie-ant fungi. The researchers suggest that the endophytic lifestyle may be an ancestral trait, retained from the fungi’s origins as plant-associated organisms. Molecular studies have shown that Ophiocordyceps is closely related to other fungi that live within plants, and the ability to colonize plant tissues may have provided the evolutionary stepping stone for the fungi’s later colonization of insects. If so, the zombie-ant fungi’s famous mind-control abilities may have evolved from a more mundane capacity to live within plants.

The findings have implications for conservation as well. The Adolpho Ducke Reserve is one of the few remaining patches of primary rainforest within Manaus, and it faces pressures from urbanization and climate change. If Ophiocordyceps depends on bryophytes for part of its life cycle, then the conservation of these fungi may require the protection of the mosses and liverworts they inhabit. Bryophytes are sensitive to environmental changes, including drying and pollution, and their decline could have cascading effects on the fungi that depend on them.

The researchers plan to continue their work in the Amazon, investigating the physiological interactions between Ophiocordyceps and its bryophyte hosts. They hope to determine whether the fungi receive nutrients from the plants, whether they reproduce within the bryophyte tissues, and whether the endophytic stage is essential for the fungi’s survival. They also plan to survey other regions of the Amazon to see how widespread the phenomenon is. For now, the study stands as a vivid reminder that even the most famous parasites in the natural world may have hidden lives waiting to be discovered, living quietly within the green carpets of the rainforest floor.

Subject of Research: Ecology and life cycle of Ophiocordyceps fungi in Amazonian bryophytes

Article Title: Metabarcoding reveals a hidden endophytic stage of the 'zombie-ant' fungus in Amazonian mosses

Article References: Alves-Júnior, T., Araújo, J. P. M. D., Góes-Neto, A., Mendes-Pereira, T., & Zartman, C. E. (2026). Metabarcoding reveals a hidden endophytic stage of the 'zombie-ant' fungus in Amazonian mosses. IMA Fungus, 17, Article e196998. https://doi.org/10.3897/imafungus.17.196998

Image Credits: AI Generated

DOI: 10.3897/imafungus.17.196998

Keywords: mycology, parasitology, entomology, bryophytes, Amazon rainforest, symbiosis, fungi, Metabarcoding, reveals, hidden, endophytic, stage

The yellow mealworm, Tenebrio molitor, occupies a peculiar dual role in human affairs. It is a notorious pest that infests stored cereal products, yet it is simultaneously one of the most valuable and nutritionally rich insects used in both animal and human food industries. Researchers describe it as a beneficial pest precisely because of this contradiction. Beyond its agricultural significance, the species can degrade polystyrene and plastic waste, making it an object of interest for waste management research, and it serves as a model organism in laboratories worldwide.

Gregarines are parasitic protozoans belonging to the phylum Apicomplexa, a group that includes some of the most notorious parasites of invertebrates. These single-celled organisms colonize the digestive tracts of many different insect species, and their effects on hosts have proven remarkably complex. Numerous experimental studies have documented both detrimental and beneficial outcomes. On the harmful side, gregarines can arrest host development, cause mortality, and inhibit reproduction. On the beneficial side, some studies have shown they can increase host growth, fitness, and longevity, complicating any simple assessment of their ecological role.

The research team dissected forty larval and forty adult mealworms from each location, examining their intestines under microscopes at magnifications ranging from 10x to 1000x. When parasitic infections were observed, the scientists prepared Giemsa-stained smears to visualize the parasites in greater detail. The slides were air-dried, fixed with methanol, and stained with a freshly prepared 5 percent Giemsa solution before re-examination. The team then measured key anatomical structures of the parasites, including the length of the epimerite, deutomerite, and protomerite, along with total body length and various width ratios that help distinguish between gregarine species.

The results revealed a dramatic contrast between the two populations. In the Tbilisi samples, gregarine infection was present in both life stages, with several life stages of the parasite found in the midgut lumens of larvae and adults alike. Each trophozoite was elongate with a bud-type epimerite measuring 5.5 micrometers, and the largest trophozoite observed reached 67.9 micrometers in length. The sporadins found in the midgut lumen were solitary, with a clearly distinct septum separating the protomerite from the deutomerite, and the deutomerite was ovoid to ellipsoid with a spherical nucleus averaging 10.3 micrometers in diameter.

Infection rates differed sharply between life stages. Twenty-nine of the forty examined larvae were infected, representing a 72.5 percent infection rate, while only seven of the forty examined adults carried the parasite, corresponding to just 17.5 percent. This substantial difference suggests that mealworm larvae are considerably more susceptible to gregarine infection than adults, a finding that carries practical weight for insect farmers who rear larvae as the primary product for food and feed applications.

In stark contrast, the Antalya population from Türkiye showed no gregarine infection whatsoever, neither in larvae nor in adults. This complete absence of the parasite in one geographic population while another shows high infection rates raises intriguing questions about how gregarines spread within and between insect colonies, and what environmental or management factors might explain such divergent outcomes between facilities located in different countries.

To identify the parasites, the researchers compared their morphological measurements and ratios against a well-documented comparative study by Clopton and colleagues from 1991, which described the morphology and general appearance of gregarine species infecting T. molitor. According to a recent review of harmful and beneficial symbionts of the mealworm, four eugregarine species are known to infect this insect: Gregarina cuneata, G. polymorpha, G. niphandrodes, and G. steini, with G. cuneata considered the most impressive and complex among them. The parasites found in the Georgian population resembled both G. cuneata and G. niphandrodes in body morphology and general appearance, yet they differed from published descriptions in their morphological measurements and ratios.

This discrepancy becomes particularly interesting when considering host stage specificity. Clopton and colleagues reported that G. polymorpha and G. steini are found only in mealworm larvae, whereas G. niphandrodes was reported only from adults. Gregarina cuneata, by contrast, infects both larvae and adults. Because the Georgian parasites were detected in both life stages, the researchers suggest that more than one gregarine species might be infecting the Georgian population, or that multiple species could coexist within the same individual host. The possibility even remains that a previously unknown gregarine species could be identified from Georgian mealworm populations.

The findings arrive at a critical moment for the edible insect industry. High-density rearing conditions associated with mass production may increase the risk of disease and infections by parasitic symbionts, promoting their spread within insect colonies. These pathogens could potentially be passed to humans and animals consuming mealworms as food, making parasite surveillance a food safety concern as well as a production issue. The researchers call for further characterization of the gregarines in Georgian mealworm populations, including molecular phylogeny studies, and recommend documenting the presence and distribution of these parasites across other Georgian populations. Such work will be essential for understanding whether the parasites represent a threat to commercial production or simply another facet of the complex biology of an insect that humanity increasingly relies upon for sustainable protein.

Subject of Research: Gregarine parasite infection in yellow mealworm populations in Georgia and Türkiye

Article Title: Occurrence of gregarine parasites of Tenebrio molitor ( Coleoptera : Tenebrionidae ) in Georgia and Türkiye

Article References: Yaman, M., Kereselidze, M., & Güvendik, T. S. (2025). Occurrence of gregarine parasites of Tenebrio molitor (Coleoptera: Tenebrionidae) in Georgia and Türkiye. Caucasiana, 4, 119-124. https://doi.org/10.3897/caucasiana.4.e164996

Image Credits: AI Generated

DOI: 10.3897/caucasiana.4.e164996

Keywords: gregarine parasites, Tenebrio molitor, yellow mealworm, Apicomplexa, insect farming, edible insects, Georgia, Türkiye, parasitology, food safety, entomology, sustainable protein

Hydatid disease, known medically as cystic echinococcosis, is caused by the larval stage of the tapeworm Echinococcus granulosus. The parasite cycles between dogs and livestock such as sheep, and humans become accidental hosts when they ingest tapeworm eggs shed in canine feces. Once inside the human body, the larvae travel through the bloodstream and typically settle in the liver, which accounts for 60 to 70 percent of cases, or the lungs, which account for 20 to 30 percent. The disease remains endemic across the Mediterranean basin, the Middle East, and parts of South America, where it poses a continuing public health challenge.

The spleen, however, is an extraordinarily rare destination for the parasite. Splenic involvement represents only 1.5 to 4 percent of all hydatid cases, and it usually occurs alongside disease in other organs. A truly isolated splenic cyst, with no trace of infection anywhere else in the body, is a clinical curiosity. The parasite is thought to reach the spleen either through the systemic circulation after slipping past the filtering capillary beds of the liver and lungs, or by traveling backward through the portal venous system. Because the organ is so rarely affected, clinicians seldom consider it early, and the slow-growing nature of the cyst compounds the problem, allowing the abdominal cavity to quietly accommodate the expanding mass for weeks or months.

That is precisely what happened in this patient. She reported no fever, no weight loss, no trauma, and no significant contact with dogs or livestock, though she lived in an endemic region. On examination, her abdomen was soft and non-tender, with no palpable mass and no enlargement of the spleen. Her complete blood count, liver function tests, and inflammatory markers were all within normal limits, and notably, she showed no hypereosinophilia, the elevation of a particular white blood cell type that often signals parasitic infection. By every conventional measure, she appeared entirely healthy.

The first clue came from imaging. An abdominal ultrasound revealed a finely echogenic cystic formation embedded within the splenic parenchyma. To characterize the lesion further, the team obtained a contrast-enhanced computed tomography scan, which showed a well-circumscribed, oval, hypodense, and homogeneous mass at the upper pole of the spleen, measuring 50 by 57 by 56 millimeters. The cyst wall was thin and regular, marked by a small area of peripheral calcification, and there was no internal septation, no endoluminal budding, and no contrast enhancement. These features were suggestive of a hydatid cyst, but they were not pathognomonic, meaning they could not definitively distinguish the parasite from other possibilities.

Then came the diagnostic twist. An enzyme-linked immunosorbent assay, or ELISA, specific for Echinococcus returned a negative result. The test was not repeated, and no complementary immunoblot or quantitative antibody measurement was available, so the surgical team could not rule out a low antibody titre or an assay-related false negative. The differential diagnosis remained broad: an epidermoid cyst of the spleen, a post-traumatic or post-infectious pseudocyst, and a cystic neoplasm all had to be weighed against the imaging pattern and the epidemiological context. The multidisciplinary team concluded that despite the negative serology, the radiological features in an endemic setting made a hydatid cyst the most probable diagnosis.

The biology behind the false negative is instructive. Serological testing for hydatid disease is highly sensitive for hepatic cysts, reaching 85 to 90 percent, but its performance drops significantly for splenic localizations. False negatives are frequently associated with intact cysts, dead or inactive parasites, or cysts with thick calcified walls that prevent antigen from leaking into the bloodstream. Without circulating antigen, the immune system never mounts the detectable antibody response that the test is designed to capture. In other words, the very features that made this cyst appear relatively benign on imaging, its intact wall and focal calcification, were the same features that allowed it to hide from the immune assay.

Faced with this uncertainty, the team chose an approach that balanced diagnostic confirmation with definitive treatment. Image-guided biopsy was rejected because of the risk of anaphylaxis and peritoneal seeding if a hydatid cyst were punctured. Instead, the patient underwent exploratory laparoscopy, with a plan to proceed to total splenectomy if intraoperative findings confirmed the diagnosis. Before surgery, she received vaccinations against Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b, the encapsulated bacteria against which the spleen normally helps defend. No perioperative albendazole or other antihelminthic drug was given, because the diagnosis had not been definitively established before the operation.

The surgery itself demanded meticulous technique. Intraoperative exploration revealed a cystic mass at the upper pole of the spleen with an appearance highly consistent with hydatid disease. The team dissected under low pneumoperitoneum pressure, taking strict precautions to prevent cyst rupture and intraperitoneal spillage, including early isolation of the splenic hilum and avoidance of direct instrument contact with the cyst wall. Because of the cyst’s polar position and the risk of parasitic dissemination during partial resection, a total laparoscopic splenectomy was performed, and the specimen was extracted intact within an endoscopic retrieval bag. The postoperative course was uneventful, with no fever, bleeding, or signs of anaphylaxis, and the patient was discharged just two days after surgery. Histopathological examination of the removed spleen confirmed the diagnosis, revealing the characteristic acellular laminated membrane and germinal layer of Echinococcus granulosus.

At six-month follow-up, a repeat abdominal CT showed no evidence of recurrent or disseminated disease, and the patient reported feeling entirely well, having resumed her usual activities without limitation. The case carries several lessons for clinicians working in endemic regions. A cystic splenic mass should prompt consideration of hydatid disease regardless of serological results, because a negative test reflects the limitations of assay sensitivity rather than the absence of disease, particularly for calcified or extrahepatic cysts. Laparoscopic splenectomy with a retrieval bag is a safe and definitive treatment when strict anti-spillage precautions are respected, and vaccination against encapsulated organisms is essential whenever total splenectomy is anticipated, to mitigate the lifelong risk of overwhelming post-splenectomy infection. The authors caution that a single case report cannot be generalized, and longer follow-up beyond six months would strengthen confidence in the absence of recurrence, but the diagnostic pathway they document, from a negative blood test to a confirmed parasitic cyst, illustrates a pitfall that could easily catch an unsuspecting clinician anywhere the parasite still circulates.

Subject of Research: A rare isolated hydatid cyst of the spleen with negative serology diagnosed and treated by laparoscopic splenectomy

Article Title: Case Report: Isolated splenic hydatid cyst with negative serology managed by laparoscopic splenectomy

Article References: Safta, A. B., Nasri, S., Dougaz, W., Alouani, H., Ksentini, M., Jerraya, H., & Nouira, R. (2026). Case Report: Isolated splenic hydatid cyst with negative serology managed by laparoscopic splenectomy. Frontiers in Parasitology, 5, Article 1956525. https://doi.org/10.3389/fpara.2026.1956525

Image Credits: AI Generated

DOI: 10.3389/fpara.2026.1956525

Keywords: hydatid disease, Echinococcus granulosus, echinococcosis, splenic cyst, negative serology, laparoscopic splenectomy, parasitology, CT imaging, false-negative ELISA, zoonosis, spleen surgery, post-splenectomy vaccination

The review, led by an international team of researchers spanning Spain, Venezuela, Canada, Brazil, the United Kingdom and Malaysia, systematically catalogues every published study in which untargeted metabolomics has been deployed to identify the molecular targets and modes of action of trypanocidal drugs. The findings arrive at a critical moment. While human African trypanosomiasis has been driven to fewer than 600 reported cases annually—a triumph of surveillance and vector control—Chagas disease continues to infect more than 7 million people worldwide, claiming over 10,000 lives each year. For the American form of the disease, current therapies remain deeply unsatisfactory, and the threat of drug resistance looms over both parasites.

Metabolomics works by measuring the relative abundance of hundreds of small molecules—typically under 1,500 daltons—inside cells treated with a drug, then comparing these chemical signatures against untreated controls. When researchers add a compound to cultured trypanosomes and quench their metabolism at different time points, the resulting metabolome reveals a cascade of perturbations. The substrate and product of the primary target enzyme accumulate or deplete first, while secondary effects ripple outward as the metabolic network attempts to adapt. This temporal dimension is crucial: by sampling at sublethal doses corresponding to EC50 or EC90 values, scientists can distinguish primary drug action from the parasite’s compensatory stress responses.

Among the most striking revelations concerns suramin, a colossal, highly negatively charged molecule that has treated African sleeping sickness for over a century without anyone fully understanding how it works. The drug defies the Lipinski rule of 5, weighing 1,297 daltons and carrying six sulphonic acid groups. Trypanosomes internalize it by endocytosis, bound either to low-density lipoprotein or to the surface glycoprotein ISG75. Two independent metabolomic studies have now converged on a compelling explanation: suramin accumulates inside glycosomes, the peculiar peroxisome-related organelles that house the first six or seven enzymes of glycolysis, and there it inhibits the glycolytic flux. Researchers detected rising levels of fructose 6-phosphate, fructose 1,6-bisphosphate, glycerol 3-phosphate and pyruvate, alongside collapsing cytosolic ATP. Because glycosomes occupy only about one-twentieth of the cellular volume, a nine-fold cellular accumulation could translate into roughly 180-fold concentration within the organelles—enough to reach inhibitory levels against the positively charged glycosomal enzymes that suramin’s sulphonic acid groups mimic phosphate groups to block.

The polyamine pathway offers another elegant target story. Eflornithine, a suicide inhibitor of ornithine decarboxylase, exploits a unique vulnerability of African trypanosomes: unlike mammalian cells and Trypanosoma cruzi, these parasites lack a plasma-membrane transporter for polyamines and depend entirely on their own biosynthesis. Metabolomic profiling confirmed the mechanism with textbook clarity—ornithine accumulates, putrescine and spermidine plummet, and within 24 hours the parasites begin leaking phospholipids and other metabolites as their membranes, starved of the polyamines needed for stability, disintegrate. The drug is trypanostatic for 48 hours before killing occurs through delayed membrane damage and general metabolite loss.

Benzoxaboroles, the boron-containing compounds behind the newly developed single-dose oral drug acoziborole, reveal yet another layer of metabolic detective work. Genomic resistance studies identified CPSF3, an RNA cleavage and polyadenylation specificity factor, as the primary target. But metabolomics added crucial mechanistic depth: within five hours of treatment, levels of S-adenosyl-L-methionine and 5′-methylthioadenosine surged, along with methylated and acetylated lysines. The pattern mirrored the effects of sinefungin, a known methylation inhibitor that blocks trans-splicing—the trypanosome-specific mRNA maturation process. The correlation between AdoMet accumulation and splicing inhibition was remarkably tight across a panel of benzoxaboroles with different potencies, confirming that the compounds disrupt methionine metabolism as a downstream consequence of CPSF3 blockade.

For Chagas disease, where the intracellular amastigote form hides from immune surveillance and from most drugs, metabolomic studies remain fewer but equally illuminating. Benznidazole, one of only two approved therapies, was shown to deplete the redox-active thiols trypanothione, homotrypanothione and cysteine while generating covalent adducts with cellular metabolites. The parasite’s trypanothione system—unique to trypanosomatids, where spermidine links two glutathione molecules to form the parasite’s equivalent of glutathione—represents a validated vulnerability. Meanwhile, the antimicrobial peptide cruzioseptin CZS-5, isolated from the skin of the frog Cruziohyla calcarifer, disrupted membrane integrity and energy metabolism simultaneously, with lipid-related molecules comprising nearly 57 percent of the 118 metabolites altered upon treatment.

Perhaps the most technically sophisticated application comes from a new methodology designed to triage cytochrome b inhibitors during Chagas disease drug discovery. Because phenotypic library screenings frequently identify hits against a small number of promiscuous targets, researchers developed a metabolomic signature—a list of 79 metabolites showing at least two-fold differential abundance—that distinguishes cytochrome b inhibition from other known targets including lysyl-tRNA synthetase, N-myristoyltransferase and the proteasome. The approach, validated with 17 different compounds, allows laboratories to deprioritize cytochrome b hits early in the workflow in favor of compounds acting through genuinely novel mechanisms.

The review also highlights how metabolomics can expose resistance mechanisms. Eflornithine resistance in African trypanosomes, for instance, arises from loss of the amino acid transporter TbAAT6, preventing intracellular drug accumulation—a finding that metabolomics alone could reveal because the mechanism produces a measurable decrease in intracellular drug concentration. For fluoropyrimidines like 5-fluorouracil and 5-fluoroorotic acid, metabolomic analysis showed incorporation into RNA rather than DNA, explaining why these compounds kill trypanosomes through a fundamentally different route than they do human cancer cells.

What emerges from this exhaustive survey is a discipline coming of age. Metabolomic profiling has limitations—data interpretation remains challenging, and primary effects must be carefully separated from secondary ones through time-course analysis. But when combined with reverse genetics, chemoproteomics and metabolic flux measurements, it provides an indispensable window into how drugs actually kill parasites. As sleeping sickness edges toward elimination and Chagas disease demands new safe therapies, the chemical fingerprints of trypanosome metabolism are proving to be the most powerful maps yet for navigating the path to better medicines.

Subject of Research: Metabolomic profiling for the identification of drug targets in trypanosomes

Article Title: Metabolomic profiling for the identification of drug targets in trypanosomes

Article References: Rojas-Pirela, M., Andrade-Alviárez, D., Quiñones, W., Cáceres, A. J., Gualdrón-López, M., Silber, A. M., & Michels, P. A. M. (2026). Metabolomic profiling for the identification of drug targets in trypanosomes. Frontiers in Chemical Biology, 5, Article 1907625. https://doi.org/10.3389/fchbi.2026.1907625

Image Credits: AI Generated

DOI: 10.3389/fchbi.2026.1907625

Keywords: metabolomics, trypanosomes, drug discovery, sleeping sickness, Chagas disease, parasitology, glycosomes, trypanothione, Metabolomic, profiling, identification, drug

Entamoeba histolytica is an invasive, water- and food-borne protozoan parasite and a significant contributor to parasitic disease mortality worldwide. In India, where transmission occurs primarily through the fecal-oral route, prevalence estimates range from 3 to 23 percent, with particularly high rates among children aged five to twelve. Clinical manifestations span from asymptomatic carriage to severe complications including extra-intestinal abscesses, perforating bowel disease, and toxic megacolon. The stakes of accurate diagnosis are heightened by the existence of morphologically identical but clinically distinct relatives: Entamoeba dispar is generally non-pathogenic, and Entamoeba moshkovskii, long considered a free-living species, has increasingly been implicated in gastrointestinal symptoms. Because these organisms are indistinguishable under the microscope, conventional microscopy cannot tell a patient who needs anti-amoebic therapy from one who does not.

The diagnostic challenge is especially acute for patients with ulcerative colitis. Symptoms of amoebic colitis—bloody diarrhea, abdominal pain, mucosal inflammation—overlap substantially with those of active UC, and the two conditions can coexist. Escalating immunosuppressive therapy in a patient harboring an untreated invasive parasite can be counterproductive or even catastrophic; fulminant amoebic colitis following corticosteroid therapy has been documented in the literature. Yet the role of parasitic infections during IBD flares has been comparatively neglected, with most research focusing on bacterial pathogens. The study team, led by Devyani Sharma of the Post Graduate Institute of Medical Education and Research (PGIMER) in Chandigarh, set out to determine whether real-time LAMP could close this gap in an endemic setting.

Between January 2021 and January 2023, the researchers collected 494 stool samples across four groups: 117 patients with ulcerative colitis diagnosed according to European Crohn’s and Colitis Organisation criteria, 177 patients with persistent or chronic diarrhea but no IBD diagnosis, 100 asymptomatic community participants recruited from rural villages, and 100 diseased controls with gastrointestinal symptoms other than diarrhea. Every sample was subjected to four diagnostic approaches in parallel: light microscopy after concentration, conventional PCR targeting the small subunit ribosomal RNA gene, real-time PCR with SYBR Green detection and melt curve analysis, and real-time LAMP run on a portable fluorometer. A subset of positive samples was then sequenced and subjected to phylogenetic analysis to confirm species identification.

The real-time LAMP assay was designed around two genetic targets. The first, the serine-rich Entamoeba histolytica protein gene (SREHP), is specific to E. histolytica. The second, the large subunit ribosomal RNA gene (LSU rRNA), is shared across the three Entamoeba species of interest. Because the annealing temperatures of the two amplicons were too close to allow reliable differentiation in a single duplex reaction, the team ran the two primer sets as parallel monoplex reactions in the same run—two tubes per sample. The logic of the readout is elegant: samples positive for E. histolytica amplify both targets and produce two fluorescent peaks, while E. dispar and E. moshkovskii amplify only the LSU rRNA target and yield a single peak. The reaction runs isothermally at 63 degrees Celsius for 60 minutes, eliminating the need for the repeated thermal cycling that PCR demands.

The performance figures are striking. Using Bayesian latent class analysis—a statistical framework that accounts for the fact that no single test is a perfect gold standard—the researchers calculated sensitivity of 39.4 percent for microscopy, 84.3 percent for conventional PCR, and 99.3 percent for both real-time PCR and real-time LAMP. Specificity for real-time LAMP ranged from 99.4 to 100 percent. Five samples that conventional PCR missed were successfully detected by both real-time methods, likely because PCR inhibitors present in some fecal samples suppressed the conventional reaction. The limit of detection told a similar story: conventional PCR could detect 1 nanogram of parasite DNA, real-time PCR reached 1 picogram, and real-time LAMP pushed down to 10 femtograms—the most sensitive of the three molecular techniques.

Turnaround time is where LAMP pulls decisively ahead. Real-time LAMP delivered results in about 60 minutes, compared with roughly 120 minutes for real-time PCR and 200 minutes for conventional PCR. The amplification is carried out by Bst DNA polymerase using outer and inner primers in a strand-displacement reaction that proceeds at a single constant temperature, meaning the assay can run on simple equipment—a water bath, a heat block, or the battery-powered portable fluorometer used in this study. The closed-tube format minimizes the risk of aerosol contamination from amplified DNA, and minimal post-amplification processing makes the workflow suitable for busy, resource-limited laboratories. These are precisely the conditions found in tertiary care hospitals across low- and middle-income countries, where patient load is high and molecular infrastructure may be scarce.

The clinical findings carry their own weight. Overall, 33 of 494 samples—6.7 percent—tested positive for Entamoeba by the real-time methods: 23 with E. histolytica, 9 with E. dispar, and 1 with E. moshkovskii. Among the 117 UC patients, 20 were positive, 17 of them with E. histolytica. Notably, patients with active UC had a higher incidence of E. histolytica infection—13 of 88—than those in remission, at 4 of 29. E. histolytica rates in the UC group were significantly higher than in the control groups (p<0.001), though the difference between active disease and remission did not reach statistical significance (p=0.898). Microscopy, meanwhile, identified cysts or trophozoites in only 15 samples and missed 20 of the 33 molecularly confirmed cases, underscoring how much the field loses when it relies on the microscope alone.

The authors are careful about the boundaries of their conclusions. With only 33 positive cases, the similar diagnostic sensitivity of real-time LAMP and real-time PCR may reflect limited statistical power, and larger multicentric studies are needed to confirm the equivalence. The parallel monoplex format, while necessary for accurate species differentiation with the available master mix chemistry, doubles reagent consumption per sample; the researchers suggest that the instrument’s dual-channel fluorescence system with sequence-specific probes could enable single-tube multiplexing in future iterations. The study was cross-sectional and diagnostic in design, so it could not establish whether E. histolytica infection drives UC disease activity or merely coexists with it, nor could it assess the effect of anti-amoebic treatment on UC outcomes. Cost-effectiveness analysis was not performed, and the authors flag it as a priority for further work.

Even with these caveats, the implications for clinical practice are concrete. The findings support considering molecular testing in microscopy-negative cases, particularly in high-incidence areas and among high-risk patients such as those with ulcerative colitis experiencing diarrhea exacerbations. Before escalating immunosuppressive therapy, the data suggest, clinicians in endemic regions should have access to a rapid, sensitive test that can distinguish a pathogenic invader from a harmless commensal. Real-time LAMP, with its hour-long turnaround, portable hardware, and PCR-equivalent accuracy, offers a plausible route to that standard—one that could reshape how amoebic infection is ruled out in the populations least equipped to wait for an answer.

Subject of Research: Evaluation of real-time LAMP for detecting and differentiating Entamoeba species in stool samples from ulcerative colitis patients and controls in North India

Article Title: Evaluation of real-time LAMP assay for detection of Entamoeba species in clinical stool samples from a tertiary care center in North India

Article References: Sharma, D., Dutta, U., Rattan, D., Kaur, U., Inoue, S., Hamano, S., Jain, R., Sandha, K. S., Sehgal, R., & Lakshmi, P. V. M. (2026). Evaluation of real-time LAMP assay for detection of Entamoeba species in clinical stool samples from a tertiary care center in North India. Frontiers in Parasitology, 5, Article 1937802. https://doi.org/10.3389/fpara.2026.1937802

Image Credits: AI Generated

DOI: 10.3389/fpara.2026.1937802

Keywords: Entamoeba histolytica, real-time LAMP, molecular diagnostics, ulcerative colitis, amoebiasis, stool testing, parasitology, India, diagnostic sensitivity, inflammatory bowel disease, isothermal amplification, Entamoeba dispar