The single-pair diagnostic study combined clinical examinations, ultrasonography, hormone and blood analyses, semen assessment and cytogenetic screening, so it could not establish how common these findings are among captive jaguars or establish a population-wide cause of reproductive failure. The animals had lived together since they were five months old and had mated repeatedly for four years without a recorded pregnancy. The female had never produced a litter and, to the investigators’ knowledge, had never been pregnant.

Both were selected for breeding through the European Association of Zoos and Aquariums’ European Endangered Species Programme on the basis of a low inbreeding coefficient. They shared an outdoor and indoor enclosure totalling 900 square metres, received water ad libitum and were fed twice weekly with red meat supplemented with a commercial carnivore vitamin and mineral preparation. Their management context matters because the programme seeks to retain genetic diversity in a self-sustaining population, but incomplete pedigree records prevent mean-kinship and inbreeding coefficients from being used universally in pairing decisions.

The study’s reproductive assessment began with anaesthesia and included external and internal clinical examinations, transabdominal ultrasonography and blood collection. The female was examined 14 days after her last oestrous period, while the male’s penis, prepuce and testes were inspected and measured. The female’s non-seasonal oestrous cycle lasted 54 to 62 days, with behavioural oestrus lasting nine to 12 days and mating occurring multiple times per hour.

Ultrasound identified small follicular structures measuring 2 to 3 mm in both ovaries but no pathological uterine changes. Her serum progesterone concentration exceeded the assay’s upper reporting limit of 40 ng/mL, a result interpreted as a non-pregnant luteal phase consistent with recent ovulation and active luteal function. Digital examination of the female did reveal a circumferential mucosal fold at the junction of the vestibule and vagina that admitted only one finger.

The investigators considered that it might be a normal anatomical variant or mild congenital stenosis, but said it was not likely to prevent the vaginal stimulation required for mating-induced reflex ovulation. They flagged potential relevance to a future pregnancy and to transcervical insemination, noting that vaginoscopy under anaesthesia would be needed for further characterization. Apart from this finding, the female’s clinical and ultrasonographic results were unremarkable.

Her progesterone profile indicated that the hypothalamic-pituitary-gonadal axis was functioning, while the absence of pregnancy indicated that ovulation was occurring without successful fertilization and implantation. The male’s testes had normal texture on palpation and no pathological changes on ultrasound, and his penis could be protruded normally with the spines expected in jaguars. Semen nevertheless showed severe abnormalities.

Electroejaculation under anaesthesia yielded 1.3 mL containing 33 million spermatozoa per millilitre, for a total of 42.9 million cells per ejaculate. Subjective assessment found 10% motility and a progressive status score of 2 on a five-point scale. Morphological examination of 200 spermatozoa identified only 5% as normal.

Abnormal midpieces and bent or coiled tails can be associated with mitochondrial dysfunction and impaired flagellar movement, both of which can hinder sperm penetration. These semen measurements were below the published reference ranges given for electroejaculated captive jaguars, which have reported total motility of 57% to 77% and between 27% and 81% morphologically normal spermatozoa. Extreme teratozoospermia alone does not always prevent a jaguar from producing offspring: a previous report described a male with only 10% normal sperm that successfully fathered young, apparently because his sperm concentration was sufficient.

The combined findings in the present male—low concentration, markedly reduced progressive motility and 95% of spermatozoa with abnormal morphology—therefore represented a more substantial reproductive limitation than abnormal shape alone. The study identified the semen abnormalities as the principal factor associated with the pair’s failure to conceive, while not establishing their underlying cause. Blood measurements supplied additional clinical context but did not reveal a defined reason for the poor semen quality.

Both animals had elevated amylase concentrations—2,242 U/L in the female and 1,966 U/L in the male—and lipase concentrations of 112 to 113 U/L. These values can accompany pancreatitis, but neither jaguar displayed clinical signs of that condition. The investigators proposed that a high-fat meal shortly before blood collection might have contributed to the results and noted that future sampling would require a standardized fast of at least 12 hours.

The male’s serum testosterone concentration was 4.74 ng/mL, within the domestic-cat interval used because no jaguar-specific interval was available, but a single sample could not represent endocrine status because testosterone fluctuates over time. His free thyroxine was below the domestic-cat lower limit, although he had no clinical signs of hypothyroidism and no jaguar-specific reference interval was available for definitive interpretation. Cytogenetic analysis found no evidence that a chromosomal abnormality explained the reproductive outcome.

Both animals had 2n = 38 chromosomes in the standard feline arrangement, comprising autosomal groups A1–A3, B1–B4, C1–C2, D1–D4, E1–E3 and F2–F3, together with one pair of sex chromosomes. G-banding produced corresponding patterns in the male and female apart from the more homogeneous male Y chromosome. C-banding identified heterochromatic sex chromosomes and two pericentromeric blocks on chromosome pair E1.

Reversed CMA3/DAPI staining revealed GC-rich telomeric regions, while telomeric fluorescence in situ hybridization showed normal terminal distribution of TTAGGG repeats without interstitial signals that would indicate cryptic rearrangements. A 28S ribosomal DNA probe and silver staining of nucleolar organizer regions located the active nucleolar organizer region on the short arm of chromosome pair E1. According to the authors, the work provided the first molecular cytogenetic characterization of Panthera onca incorporating C-banding, CMA3/DAPI staining, telomeric fluorescence in situ hybridization and ribosomal DNA probes.

It supplies a reference baseline for comparative studies of chromosome evolution in felids and for diagnostic karyotypic screening in captive jaguars. The study did not find compelling evidence that these European captive-born animals had a karyotype categorically distinct from the standard feline arrangement reported previously. Differences in centromeric index noted against an earlier jaguar report could reflect chromosome selection, preparation quality or genuine population-level variation, but the two-animal sample was too limited to distinguish among those possibilities.

The findings leave the assisted-reproduction prognosis uncertain rather than definitively excluding it. Severe semen abnormalities constrain natural breeding, and jaguar sperm cryopreservation remains difficult: a review of six independent trials found post-thaw motility ranging from 4.3% ± 2.5% to 46.0% ± 7.7%, with most protocols below 30% even when fresh motility exceeded 90%. Sperm-selection techniques might enrich the small motile and morphologically normal fraction, and intracytoplasmic sperm injection could theoretically bypass some barriers associated with poor semen quality, but neither had been reported in jaguars.

The study itself was limited by its examination of only one pair, a single semen collection, subjective motility scoring, the absence of faecal glucocorticoid measurements and reliance on some domestic-cat reference intervals. Repeated semen evaluations and objective computer-assisted sperm analysis were described as necessary follow-up measures, alongside functional testing of acrosome integrity and DNA fragmentation.

Subject of Research: Reproductive and cytogenetic investigation of infertility in one captive jaguar breeding pair

Article Title: Integrated Reproductive and Cytogenetic Assessment of Infertility in a Captive Jaguar (Panthera onca)

Article References: Altmanová, M., Strand, J., Kirchhoff, K. T., & Majtánová, Z. (2026). Integrated Reproductive and Cytogenetic Assessment of Infertility in a Captive Jaguar ( Panthera onca ). Veterinary Medicine and Science, 12(6), Article e71192. https://doi.org/10.1002/vms3.71192

Image Credits: AI Generated

DOI: 10.1002/vms3.71192

Keywords: captive jaguar, infertility, semen analysis, teratozoospermia, sperm motility, cytogenetics, karyotype, conservation breeding, assisted reproduction, wild felids, Integrated, Reproductive

The 2015 edition of the LeishVet review emerged at a time when interest in feline leishmaniosis was growing but the evidence base remained thin. The disease, caused primarily by the protozoan parasite Leishmania infantum and transmitted by phlebotomine sand flies, had been documented in cats across endemic regions, yet most of what clinicians knew came from isolated case reports. In the intervening decade, the landscape has shifted considerably. Veterinary awareness of the disease has increased, diagnostic support has become more widely available, and a steady stream of prevalence studies, clinical descriptions and treatment reports has accumulated in the literature.

Despite this progress, the authors are candid about the limitations of the current evidence. Knowledge of feline leishmaniosis still derives largely from case reports and small case series, with fewer analytical studies and a lower overall level of evidence than is available for canine leishmaniosis. Dogs remain the principal reservoir host of L. infantum and the model species for most leishmaniosis research, meaning that extrapolation from canine data to feline patients must be made cautiously. It is precisely this gap that the updated review seeks to address, combining key international publications with the clinical expertise and structured consensus of the expert panel.

To make the guidance as usable as possible, the panel organized the review around a series of questions covering the aspects of the disease most relevant to practitioners. These span the etiology of the infection, its transmission dynamics, its epidemiology including geographical distribution and risk factors, the immunology of the host-parasite relationship in cats, the range of clinical presentations and clinicopathological findings, the role of coinfections and comorbidities, diagnosis, prognosis based on clinical staging, treatment, monitoring and prevention. Each answer is supported by visual aids, including tables, figures and algorithms designed to guide clinical decision-making at the point of care.

The review focuses primarily on L. infantum infection and disease in domestic cats, reflecting the fact that this species is by far the most frequently diagnosed cause of leishmaniosis in felines. However, the panel also devoted two specific questions to topics that extend beyond the household cat. One addresses infection in wild felids, providing support for veterinary specialists working in wildlife and zoo medicine, where leishmaniosis has increasingly been recognized. The other considers Leishmania species other than L. infantum, an issue of growing relevance as globalization moves animals, vectors and pathogens across borders and presents practitioners with new diagnostic challenges.

Supporting the epidemiological sections of the review are two extensive supplementary tables compiled from data published between 2015 and 2025. The first covers the prevalence of Leishmania infection in cats in Old World countries, and the second covers the New World, drawing on both serological and molecular detection techniques. These tables catalogue the sampling periods, the characteristics of the studied cat populations and the variables associated with test positivity, and in nearly all cases the species involved was confirmed or presumed to be L. infantum. Together they represent one of the most complete pictures to date of how widely the parasite circulates among cats across both hemispheres.

On the diagnostic front, the review reflects the expanded toolkit now available to clinicians. Serological methods such as the indirect fluorescent antibody test, enzyme-linked immunosorbent assay and the direct agglutination test can detect antibody responses, while molecular techniques, including quantitative real-time polymerase chain reaction, allow parasite DNA to be detected and quantified in tissue and blood samples. Cytology, histopathology and immunohistochemistry remain important for demonstrating amastigote forms in lesions. The panel’s recommendations emphasize how these tools should be interpreted in combination, since infection and clinical disease are not the same thing, and cats can carry the parasite without showing signs of illness.

Coinfections and comorbidities receive particular attention in the updated guidance, reflecting the complex clinical reality of feline medicine. Retroviral infections with feline immunodeficiency virus and feline leukaemia virus, chronic kidney disease and immune-mediated conditions such as immune-mediated hemolytic anemia and feline chronic gingivostomatitis can all complicate the picture in a cat infected with L. infantum. The review also incorporates modern monitoring parameters relevant to feline patients, including urinary protein-to-creatinine ratios and symmetric dimethylarginine, which are used in staging and tracking chronic kidney disease under the International Renal Interest Society framework. These considerations matter because treatment decisions and prognosis in cats must account for the whole patient, not just the parasite.

Treatment and prevention recommendations are likewise updated in light of the past decade’s experience. Therapeutic options discussed in the context of feline leishmaniosis include allopurinol, meglumine antimoniate and miltefosine, the drugs that form the backbone of therapy in canine leishmaniosis, with the panel weighing their use against the specific pharmacological and safety considerations that apply to cats. Clinical staging is presented as the basis for formulating a prognosis and tailoring monitoring plans, mirroring the staged approach long used in canine medicine. Prevention advice addresses reducing exposure to sand fly vectors, an approach that becomes increasingly important as the geographic footprint of leishmaniosis expands.

The publication of this update comes at a moment when the boundaries of leishmaniosis are shifting. Climate change, animal movement and urbanization are altering the distribution of sand fly vectors and bringing previously unaffected populations of both dogs and cats into contact with L. infantum. For practitioners in endemic areas, the message of the review is that feline leishmaniosis should no longer be treated as a rare curiosity but as a differential diagnosis in cats with compatible clinical signs. For those in emerging areas, the review provides a framework for recognizing a disease they may never have been taught to look for. By consolidating a decade of scattered evidence into structured, consensus-based recommendations, the LeishVet panel has given veterinary medicine its clearest roadmap yet for understanding, diagnosing and managing leishmaniosis in one of its most overlooked hosts.

Subject of Research: Updated veterinary recommendations for the diagnosis, treatment and prevention of feline leishmaniosis caused by Leishmania infantum

Article Title: LeishVet update and current recommendations on feline leishmaniosis

Article References: Pennisi, M. G., Baneth, G., Bourdeau, P., Cardoso, L., Miró, G., Ordeix, L., Solano-Gallego, L., & Oliva, G. (2026). LeishVet update and current recommendations on feline leishmaniosis. Parasites & Vectors, 19(1), Article 421. https://doi.org/10.1186/s13071-026-07642-4

Image Credits: AI Generated

DOI: 10.1186/s13071-026-07642-4

Keywords: feline leishmaniosis, Leishmania infantum, LeishVet, cats, sand flies, veterinary parasitology, diagnosis, clinical staging, treatment, prevention, wild felids, coinfections