African animal trypanosomoses, caused by single-celled protozoan parasites of the genus Trypanosoma and transmitted exclusively through the bite of tsetse flies of the genus Glossina, remain one of the most formidable constraints on livestock productivity across sub-Saharan Africa. The disease devastates cattle herds, undermines plough-based agriculture, and imposes economic losses that ripple through rural communities already living at the edge of poverty. What makes the problem especially intractable is the ecology: tsetse flies feed on a wide range of vertebrate hosts, including wildlife that can carry trypanosomes without apparent illness, meaning that protected areas can act as reservoirs from which infection spills over into domestic animals and, occasionally, into people themselves.

Mozambique is a particularly instructive place to study this dynamic. The country harbours four main tsetse species, and pathogenic trypanosomes circulate widely in both wildlife and livestock. As human populations grow and agricultural activity intensifies around the edges of national parks, the interfaces where people, cattle, and wild animals meet have expanded, raising the risk of disease transmission in both directions. To understand exactly what is happening at these contact zones, the team concentrated its fieldwork on two contrasting landscapes: Maputo National Park in the south of the country and Gorongosa National Park in the centre, together with the agricultural buffer zones that surround each protected area.

The field effort was substantial. Using traps deployed inside the parks and in their buffer zones, the researchers collected 2,291 tsetse flies representing four species: Glossina austeni, Glossina brevipalpis, Glossina morsitans and Glossina pallidipes. Each specimen was identified using standard taxonomic keys, and a subsample of 200 flies was then selected for whole-body DNA extraction. From that genetic material, the team amplified and sequenced several molecular barcodes, targeting the internal transcribed spacer region to identify trypanosomes, mitochondrial markers to trace blood meal sources, and the 16S ribosomal RNA gene to profile the bacterial microbiome living inside each fly.

The trypanosome results were striking. Overall infection prevalence ranged from 65 to 90 percent depending on the fly species, an extraordinarily high parasite burden that underscores how intensively trypanosomes circulate in these landscapes. Seven distinct Trypanosoma species or subspecies were detected across the sampled flies. Trypanosoma brucei, the species group that includes the parasites responsible for human sleeping sickness, was the most abundant, found in 35 percent of flies, followed by Trypanosoma godfreyi at 20 percent. The team also identified Trypanosoma congolense Kilifi, Trypanosoma congolense Savannah, Trypanosoma simiae, Trypanosoma simiae Tsavo and Trypanosoma vivax, a roster that spans the full spectrum of parasites responsible for wasting diseases in cattle, pigs and other livestock.

Just as revealing was the blood meal analysis. By sequencing host DNA remaining in the flies’ guts, the researchers identified 17 different vertebrate host species, with wildlife predominating over domestic animals. Two hosts stood out at the top of the list: warthogs accounted for 26 percent of identified blood meals, and humans accounted for 25 percent. That human blood appears so frequently in the diet of these flies is a sobering finding, because it demonstrates that the ecological circuit connecting wild reservoirs, vectors and people is not hypothetical but an everyday occurrence. Cattle and other domestic animals also featured among the identified sources, confirming that livestock are woven into the same transmission network rather than standing apart from it.

The microbiome profiling added a third layer to the picture. Inside the flies, the dominant bacterial symbionts were Wigglesworthia and Wolbachia, two genera with well-known roles in tsetse biology. Wigglesworthia is an obligate mutualist housed in specialised bacteriomes that supplies nutrients the fly cannot obtain from its blood-only diet, and it has been implicated in vector competence and fertility. Wolbachia, by contrast, is a notorious reproductive manipulator that can bias host sex ratios and is being explored worldwide as a tool for controlling insect-borne diseases. Mapping which bacteria coexist with which parasites in which fly species provides raw material for future biocontrol strategies that might exploit these internal partnerships.

Perhaps the most important analytical finding concerns what actually shapes this entire system. When the researchers modelled the relationships among trypanosome diversity, host selection and microbiome composition, they found that the species of tsetse fly was the dominant explanatory factor, while location, meaning the difference between the parks and their surrounding buffer zones, played only a secondary role. In other words, the biology of the vector itself, rather than the immediate landscape it inhabits, is the strongest organising force in the transmission cycle. A constrained ordination analysis of blood meal variation showed that tsetse species together explained 96 percent of the total variance in community composition, a statistically significant association that highlights how tightly each fly species is bound to its own host preferences and parasite suite.

This species-level structure has practical consequences. Different Glossina species occupy different ecological niches, prefer different hosts, and harbour different combinations of trypanosomes, so a single blanket intervention is unlikely to succeed everywhere. Control programmes in the Gorongosa region, where G. morsitans and G. pallidipes dominate, may need different tactics from those around Maputo, where G. austeni and G. brevipalpis prevail. The finding that wildlife, particularly warthogs, sustain so many blood meals suggests that reservoir management and vector control must be designed together, and the prominence of humans in the blood meal record argues for surveillance of human African trypanosomosis even in areas where it is not currently considered a major clinical problem.

The study’s authors frame their results within a One Health perspective, the recognition that human, animal and environmental health are inseparable. By documenting the full diversity of vectors, parasites, hosts and microbes at the conservation–agriculture interface, the research provides the evidence base needed to design targeted, locally appropriate control strategies rather than generic ones. Funded by the European Union’s Horizon 2020 programme through the COMBAT project, which aims to control and progressively minimise the burden of animal trypanosomosis, the work demonstrates how molecular tools can transform our understanding of neglected tropical disease systems. As agricultural frontiers continue to press against Africa’s protected areas, studies like this one make clear that the fate of livestock, wildlife and people will be decided in the shared landscapes between them, one tsetse bite at a time.

Subject of Research: Tsetse fly-borne trypanosome transmission, blood meal hosts and microbiome diversity at wildlife–livestock–human interfaces in Mozambique

Article Title: Tsetse flies, trypanosomes, hosts and microbiome diversity at agricultural–conservation interfaces in Mozambique

Article References: Brito, D. R. A., Mulandane, F. C., Cossa, N. V., Mucache, H. N., Moo-Millan, J. I., Manzanilla, V., Boulangé, A., Waleckx, E., & Neves, L. (2026). Tsetse flies, trypanosomes, hosts and microbiome diversity at agricultural–conservation interfaces in Mozambique. Parasites & Vectors. https://doi.org/10.1186/s13071-026-07660-2

Image Credits: AI Generated

DOI: 10.1186/s13071-026-07660-2

Keywords: tsetse flies, trypanosomes, African animal trypanosomosis, Mozambique, Glossina, blood meals, microbiome, Wigglesworthia, Wolbachia, One Health, wildlife reservoirs, metabarcoding

Trypanosomatid flagellates such as Trypanosoma brucei and T. cruzi have long fascinated cell biologists because their endocytic traffic is confined to a single invagination of the plasma membrane called the flagellar pocket. This unusual geometry makes them powerful models for testing how universal the principles of membrane trafficking really are. Previous work had catalogued many components of clathrin-mediated endocytosis in these parasites, but the composition and evolutionary standing of their ESCRT machinery remained incompletely resolved. In animals and fungi, a subcomplex called ESCRT-0, built around the Vps27/Hrs and STAM proteins, recognises ubiquitylated substrates and hands them to the downstream complexes. Whether trypanosomes possess anything comparable has been an open question.

The team approached the problem from two directions: comparative genomics across the eukaryotic tree and experimental biochemistry in the parasite itself. Using hidden Markov model searches and reciprocal best BLAST analyses, they surveyed hundreds of genomes from every major eukaryotic supergroup for orthologs of candidate sorting proteins. In parallel, they engineered procyclic-form T. brucei cells to express an endogenous GFP-tagged version of Vps23, the Tsg101 orthologue that anchors the ESCRT-I complex. Affinity purification followed by quantitative mass spectrometry then pulled down the proteins that travel with TbVps23 in living cells, allowing the researchers to confirm predicted partners and uncover unexpected ones.

The most striking biochemical discovery was that trypanosome ESCRT-I is not the canonical heterotetramer familiar from yeast and animals. Instead, the purification identified two novel Vps23-interacting proteins, encoded by adjacent open reading frames Tb927.11.2020 and Tb927.11.2030, that travel stoichiometrically with the core subunits. These proteins are specific to trypanosomes, with no obvious homologues outside the kinetoplastid lineage, and their association with Vps23 indicates that the trypanosome ESCRT-I subcomplex is a heteropentamer. The finding adds a new tier of compositional divergence to a complex long considered structurally conserved, and it underscores how evolutionary flexibility can be woven into even the most fundamental cellular machines.

Equally consequential is the team’s answer to the question of what serves as the trypanosome ESCRT-0 analogue. Rather than a Vps27/STAM pair, which the analyses confirmed is absent from most non-opisthokont lineages, the parasites employ Tom1, a protein carrying the VHS and GAT domains that is broadly distributed across eukaryotes. The researchers demonstrated that trypanosome Tom1, termed TbTom1, colocalises with TbVps23 at endosomal membranes and interacts with a kinetoplastid-specific partner protein the authors nicknamed Jerry, a multi-domain protein studded with three FYVE domains, lipid-binding modules that recognise endosomal phosphoinositides. Together, Tom1 and Jerry appear to fulfil the substrate-recognition role that ESCRT-0 plays in fungi and animals, but through entirely different molecular parts.

Structural predictions reinforced the ancient pedigree of this arrangement. AlphaFold3 modelling of TbTom1 revealed a compact, well-ordered VHS helical bundle linked to a GAT domain, closely superimposable on the VHS domain of human TOM-1, while the remaining regions of the protein are predicted to be intrinsically disordered. This architecture supports the authors’ proposal that Tom1 is the ancestral VHS-GAT-domain-containing cargo adaptor, present in the last common ancestor of eukaryotes and retained across supergroups, whereas the Vps27/Hrs-STAM system of ESCRT-0 is a later innovation restricted to animals and fungi. By mapping the occurrence of Tom1 and Jerry orthologues across the Euglenozoa, the researchers showed that Tom1 is universally retained within the phylum while Jerry is absent from diplonemids, tracing a lineage-specific layer of specialisation on top of a conserved core.

The experimental evidence connecting these proteins to endocytic function came from cellular phenotyping. Cells expressing tagged versions of TbTom1 or TbJerry showed significantly enlarged flagellar pockets, with morphometric analysis of DAPI-stained cells revealing a marked increase in pocket area compared with the parental line, and tagged TbJerry cells additionally displaying a subtle nozzle-like distortion of the pocket. Because the flagellar pocket is the sole site of endocytosis in trypanosomes, such expansion implies a direct perturbation of membrane uptake and trafficking throughput. The phenotypes were measured across individual cloned lines and validated by immunoblotting of endogenous tags, giving the morphological data a firm molecular footing.

Curiously, the machinery appears dispensable for parasite viability in laboratory culture. RNA interference targeting TbTom1 in bloodstream-form cells reduced transcript levels by roughly 65 percent yet left proliferation unimpaired over an eight-day course, and mass spectrometric profiling of the silenced proteome showed that overall protein composition shifted only modestly. Concanavalin A uptake assays, which track soluble cargo from the flagellar pocket through endosomes to the lysosome, proceeded indistinguishably in TbTom1-depleted cells and controls. The authors interpret this resilience as evidence of redundancy or adaptability within the trypanosome sorting network rather than irrelevance of Tom1, a pattern consistent with the plasticity that their comparative analyses document throughout the system.

Broadly, the study reframes how biologists should think about the early ESCRT machinery. Evidence that Tom1 functions within the ESCRT pathway of trypanosomes supplies the fourth eukaryotic supergroup in which such a role has been demonstrated, and the authors argue that Tom1, not Vps27/STAM, is likely part of the pan-eukaryotic early ESCRT apparatus. At the same time, the heteropentameric ESCRT-I complex and the kinetoplastid-restricted Jerry protein illustrate how individual lineages continue to elaborate and customise the machinery, echoing earlier discoveries such as the plant-specific FREE1 adaptor, whose orthologues the team also surveyed across embryophytes. Evolution, in this view, has conserved the skeleton of the sorting system while repeatedly rebuilding its sensory apparatus.

For parasitologists, the implications extend toward intervention. Trypanosomes depend on relentless endocytic turnover of their variant surface glycoproteins and invariant surface receptors to evade the immune system, and any component that is parasite-specific, such as the novel ESCRT-I subunits or Jerry, represents a potential Achilles heel that host proteins do not share. Conversely, the conserved Tom1-dependent pathway offers a benchmark against which the animal and fungal systems can be reinterpreted, potentially correcting an animal-centric bias that has coloured membrane trafficking research for decades. What this study makes clear is that the deepest lessons about how eukaryotic cells move their membranes may come not from yeast or human tissue culture, but from an ancient parasite whose cellular geography forces every molecular handoff to happen in one remarkable pocket of membrane.

Subject of Research: The composition and evolution of the ESCRT endosomal sorting system in trypanosome parasites

Article Title: The trypanosome ESCRT system possesses both novel components and under-recognised pan-eukaryotic features

Article References: Padilla-Mejia, N. E., Durante, I. M., Záhonová, K., Stříbrná, E., Heller, J., Dacks, J. B., Lukeš, J., & Field, M. C. (2026). The trypanosome ESCRT system possesses both novel components and under-recognised pan-eukaryotic features. BMC Biology. https://doi.org/10.1186/s12915-026-02730-4

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02730-4

Keywords: ESCRT, endocytosis, trypanosomes, Trypanosoma brucei, Tom1, Vps23, flagellar pocket, protein trafficking, endosomes, eukaryotic evolution, VHS domain, FYVE domain