EXPLORING THE ECOLOGIC BASIS FOR EXTREME SUSCEPTIBILITY OF PALLAS' CATS (OTOCOLOBUS MANUL) TO FATAL TOXOPLASMOSIS

TOXOPLASMA GONDII PREVALENCE, PARTIAL GENOTYPES, AND SPATIAL VARIATION IN NORTH AMERICAN RIVER OTTERS (LONTRA CANADENSIS) IN THE UPPER PENINSULA OF MICHIGAN, USA

Toxoplasma gondii is a ubiquitous parasitic protozoan that poses a health threat to wildlife and human health worldwide. Oocysts shed into the environment in felid host feces may persist for several years. Runoff from rainfall and snowmelt may carry the oocysts into waterways. Semiaquatic mammals such as the Northern American river otter (Lontra canadensis) are particularly at risk of exposure, as they may encounter infective stages in both terrestrial and aquatic environments. Despite this risk, only a small number of studies have examined the prevalence of T. gondii in US river otter populations. Tongue tissue was sampled from 124 otters from the Upper Peninsula of Michigan submitted by trappers to the Michigan Department of Natural Resources in the 2018-19 harvest season. Following DNA extraction, a portion of the B1 T. gondii gene was amplified with PCR. A subset of positive samples was genotyped for comparison with known T. gondii sequences. Of the 124 tongue samples, 35 (28%) were positive for T. gondii. Prevalence did not differ significantly between sexes or age classes across the entire study area. Most (53.8%) of the genotyped samples were type 4 (type 12), a genotype commonly found in North American wildlife. Genotypes 127 and 197 were also found. Three clusters of T. gondii prevalence were identified through SaTScan analysis, although they were not significant. When modeling prevalence of T. gondii with covariates at individual otter locations, the top three models included the presence of Sarcocystis, area of exotic plants, area of agriculture, and sex of the otter. Our results suggest that T. gondii is widespread in otter populations in the Upper Peninsula of Michigan.

Toxoplasmosis in Zoo Animals: A Retrospective Pathology Review of 126 Cases

Toxoplasma gondii is an extremely successful zoonotic protozoan parasite that has been demonstrated in a wide range of endo- and poikilothermic species. Although infection is widespread amongst domestic animals, overt disease other than abortion in small ruminants is sporadic. This survey evaluates toxoplasmosis in zoo animals based on a systematic review of pathology archive material (n = 33,506 submissions) over a 16-year study period. A total of 126 submissions, deriving from 32 zoos, two educational facilities and two private owners, were included in the study, based on gross lesions, cytological, histological and immunohistological diagnosis of toxoplasmosis. Clinical history, signalment, annual distribution and post-mortem findings were evaluated. A total of 31 species (mammalian 97%/avian 3%) were represented in the study material. Ring-tailed lemurs, slender tailed meerkats, Pallas’ cats, and squirrel monkeys were most affected. An unusual outbreak occurred in Asian small-clawed otters, in which toxoplasmosis has not been reported to date. Clinically, animals over 12 months of age presented with non-specific symptoms (anorexia, weight loss, lethargy, debilitation), neurological, gastrointestinal or respiratory signs and sudden death. Systemic disease predominated, with a propensity for encephalitis in meerkats and Pallas’ cats and systemic disease involving lymphoid tissues in ring-tailed lemurs. Cases in the UK occurred year-round, with species-specific peaks and increases between August and November. This study reinforces the importance of toxoplasmosis as a significant cause of sporadic and epizootic mortalities in a wide range of zoo animals. Feral cat control is crucial to reduce infection pressure.

Captivity alters neuroendocrine regulators of stress and reproduction in the hypothalamus in response to acute stress

Wild animals are brought into captivity for many reasons. However, unlike laboratory-bred animals, wild caught animals often respond to the dramatic shift in their environment with physiological changes in the stress and reproductive pathways. Using wild-caught male and female house sparrows (Passer domesticus) we examined how time in captivity affects the expression of reproductive and stress-associated genes in the brain, specifically, the hypothalamus. We quantified relative mRNA expression of a neurohormone involved in the stress response (corticotropin releasing hormone [CRH]), a hypothalamic inhibitor of reproduction (gonadotropin inhibitory hormone [GnIH]), and the glucocorticoid receptor (GR), which is important in terminating the stress response. To understand potential shifts at the cellular level, we also examined the presence of hypothalamic GnIH (GnIH-ir) using immunohistochemistry. We hypothesized that expression of these genes and the abundance of cells immunoreactive for GnIH would change in response to time in captivity as compared to free-living individuals. We found that GR mRNA expression and GnIH-ir cell abundance increased after 24 and 45 days in captivity, as compared to wild-caught birds. At 66 days in captivity, GR expression and GnIH cell abundance did not differ from wild-caught birds, suggesting birds had acclimated to captivity. Evaluation of CRH and GnIH mRNA expression yielded similar trends, though they were not statistically significant. In addition, although neuroendocrine factors appeared to acclimate to captivity, a previous study indicated that corticosterone release and immune responses of these same birds did not acclimate to captivity, suggesting that neuroendocrine endpoints may adapt more rapidly to captivity than downstream physiological measures. These data expand our understanding of the physiological shifts occurring when wild animals are brought into captivity.

USE OF CLINDAMYCIN IN PALLAS' CATS [OTOCOLOBUS (FELIS) MANUL] TO REDUCE JUVENILE TOXOPLASMOSIS-ASSOCIATED MORTALITY RATES

Pallas' cat [Otocolobus (Felis) manul] experiences a high mortality rate from toxoplasmosis. During the period 2006-2016, the overall mortality rate for this species from all causes during the first year of life was 71.59% in European Association of Zoos and Aquaria institutions, with the most significant infectious cause from systemic toxoplasmosis (20.6%) as confirmed by postmortem examination and histopathology. Clindamycin was used starting in 2014 in two collections that had previously experienced 100% mortality rates by toxoplasmosis in kittens less than one year of age, covering key Toxoplasma gondii exposure periods for kittens (n = 17) as a prophylactic measure. This protocol resulted in a 67.03% (95% confidence interval 41.76-78.61%) reduction in the first year mortality rate over a two-year period to 5.88% in those animals treated.

Toxoplasma gondii in small exotic felids from zoos in Europe and the Middle East: serological prevalence and risk factors

BACKGROUND

Toxoplasma gondii infections and cases of clinical toxoplasmosis have been recorded in zoo animals. Wild felids in human care can serve as definitive hosts that shed oocysts, but also as intermediate hosts for the parasite. Some felid species, such as the Pallas's cat (Otocolobus manul) or sand cat (Felis margarita), may suffer from clinically apparent toxoplasmosis. In the present study, our main aim was to assess risk factors for T. gondii infections in small exotic felids.

METHODS

A seroepidemiological study was conducted using the reduviid bug Dipetalogaster maxima for blood sample collection, a method previously evaluated on domestic cats. A total of 336 samples from 17 felid species were collected in 51 institutions, 48 of which were within Europe and the remaining three in the Middle East (United Arabic Emirates and Qatar). These samples were analyzed for T. gondii antibodies by immunoblotting and an immunofluorescent antibody test. Potential risk factors in zoos for seropositivity regarding T. gondii among members of the European Association of Zoos and Aquaria (EAZA) were evaluated using a questionnaire and individual data from the Zoological Information Management System (ZIMS).

RESULTS

The sampled felids showed an overall seroprevalence for T. gondii of 63%. The risk factor study including data of 311 small exotic cats of 10 species resulted in a final generalized linear mixed model comprised of five variables: the likelihood of seropositivity increased statistically significantly with "Age", while feeding "Cattle: frozen" relative to "Cattle: fresh", "Outdoor housing fenced in on all sides", "Mesh size 2-5 cm" relative to "Mesh size > 5 cm" and "Wearing gloves: yes" had statistically significant protective effects.

CONCLUSIONS

Wild felids, including endangered species, kept in human care in European and Middle Eastern institutions, are widely exposed to T. gondii. Risk factor analysis revealed that feeding previously frozen tissues, keeping animals in enclosures that are fenced on all sides using fences with small mesh sizes, and wearing gloves when working inside enclosures seem to be the most relevant protective measures to prevent T. gondii infections in these animals .

Health and zoonotic Infections of snow leopards Panthera unica in the South Gobi desert of Mongolia

Background: Snow leopards, Panthera uncia, are a threatened apex predator, scattered across the mountains of Central and South Asia. Disease threats to wild snow leopards have not been investigated.Methods and Results: Between 2008 and 2015, twenty snow leopards in the South Gobi desert of Mongolia were captured and immobilised for health screening and radio-collaring. Blood samples and external parasites were collected for pathogen analyses using enzyme-linked immunosorbent assay (ELISA), microscopic agglutination test (MAT), and next-generation sequencing (NGS) techniques. The animals showed no clinical signs of disease, however, serum antibodies to significant zoonotic pathogens were detected. These pathogens included, Coxiella burnetii, (25% prevalence), Leptospira spp., (20%), and Toxoplasma gondii (20%). Ticks collected from snow leopards contained potentially zoonotic bacteria from the genera Bacillus, Bacteroides, Campylobacter, Coxiella, Rickettsia, Staphylococcus and Streptococcus.Conclusions: The zoonotic pathogens identified in this study, in the short-term did not appear to cause illness in the snow leopards, but have caused illness in other wild felids. Therefore, surveillance for pathogens should be implemented to monitor for potential longer- term disease impacts on this snow leopard population.

Risk factors and prevalence of antibodies for Toxoplasma gondii in diaphragmatic fluid in wolverines (Gulo gulo) from the Northwest Territories, Canada

Toxoplasma gondii, a zoonotic food borne parasite that can infect almost all warm-blooded animals including people, and ranks 4th among 24 most significant global foodborne parasites listed by the World Health Organization/United Nations Food and Agriculture Organization (FAO/WHO, 2014). Exposure to T. gondii has been reported in wildlife and people in the Canadian North, despite low densities of feline definitive hosts. The ecology of this host-parasite system could be affected by changing climate and landscape in boreal and sub-Arctic regions, and surveillance data are critically needed. Wolverines are an economically and culturally important species in northern Canada due to their valuable fur. Fluid obtained from diaphragmatic muscle of 127 wolverines (Gulo gulo) were tested for antibodies to T. gondii using an enzyme linked immunosorbent assay (ELISA). A seroprevalence of 62% (Confidence Interval (CI): 53-71%) was observed. This result indicates high levels of exposure, likely either through environmental contamination with T. gondii oocysts shed by infected wild felids, or consumption of carcasses/offal of other intermediate hosts containing tissue cysts with bradyzoites in tissues. We examined factors associated with seropositivity, including age, sex, harvest location, harvest location with respect to treeline, and body condition index. Adult (≥2 years) wolverines had 5.2 times higher odds of being sero-positive than juvenile (<1 years) wolverines. The highest seroprevalence was observed in wolverines from Sahtu and South Slave regions. Proportion of sero-positive wolverines harvested above and below the tree line was not significantly different (60% vs 65%). Age was the only significant predictor of T. gondii exposure in wolverines (using logistic regression analysis); further studies should target larger sample sizes. This study is an example of how fluid from diaphragmatic muscle can be used for screening for T. gondii antibodies in wolverines. The diaphragm, commonly collected for screening for another food borne parasite, Trichinella, in wildlife harvested for human consumption, can be used for screening of T. gondii exposure in wildlife. Due to their predatory and scavenging lifestyle and high trophic level, wolverines could serve as a sentinel species for T. gondii.

Epizootological study on Toxoplasma gondii in zoo animals in the Czech Republic

Toxoplasma gondii is protozoan parasite with ability of causing disease in wide-spectrum of animals; many species of animals in captivity died of clinical toxoplasmosis. The monitoring of T. gondii antibodies in zoo animals can be an important indicator of T. gondii circulation in zoo. The aim of this study was to examine sera of animals from eight Czech zoos by latex agglutination test with statistical evaluation and detect T. gondii DNA in stray cats and rodents captured in the zoos. T. gondii antibodies were detected in 33% of 1043 zoo animals without statistical difference between birds (27%, n = 74) and mammals (33%, n = 969). In birds, the chance to be infected with T. gondii was higher in Accipitriformes (71%) compared to Pelecaniformes (6%) (p < 0.0001). In mammals, the chance to be infected with T. gondii was higher in Carnivora (63%) compared to Cetarodactyla (30%), Perissodactyla (26%), Primates (28%) and Rodentia (13%) (p < 0.0001) and higher in Felidae (70%) compared to Bovidae (28%) and Equidae (28%) (p < 0.0001). Mammals with carnivore/scavenger way of feeding were in a higher risk of T. gondii infection compared to herbivores and omnivores (p < 0.0001). T. gondii DNA was detected in tissue of one stray cat while in none of 77 rodents caught in zoo. This study is the first report on toxoplasmosis in zoos from the Czech Republic including seroepidemiology and molecular detection.

Seroprevalence of Toxoplasma gondii and Neospora caninum infections in cattle in Mongolia

Toxoplasma gondii and Neospora caninum are protozoan parasites that cause huge economic losses in animal industries worldwide. N. caninum can cause abortion storms and high culling rates in cattle, whereas T. gondii infection is a significant concern in both human and animals because it can induce abortion and clinical symptoms in immunocompromised hosts. The aim of this study was to determine the seroprevalence of T. gondii and N. caninum in cattle in Mongolia. Specific antibodies to T. gondii and N. caninum were detected by using an indirect enzyme-linked immunosorbent assay (iELISA) based on recombinant antigens of dense granule protein 7 of Toxoplasma gondii and surface antigen 1 of Neospora caninum, respectively. A total of 1438 cattle sera from 20 of 21 provinces of Mongolia and the capital city of Ulaanbaatar were tested. Overall, 18.7% and 26.2% of cattle were positive for specific antibodies to T. gondii and N. caninum, respectively. Prevalence rates were higher (T. gondii infection: P < .0001, N. caninum infection: P = .002) in the central region of Mongolia (T. gondii infection: 27.1%, N. caninum infection: 30.8%) compared with western region, suggesting that prevalence rates might be influenced by geographical condition, particularly warmer temperatures around this area in Mongolia. The lowest prevalence rates were observed in the western region of Mongolia (T. gondii: 9%, N. caninum: 20.8%). In addition, the seroprevalence of N. caninum in female animals (27.5%) was significantly higher than that in male animals (20.4%) (P = .018), suggesting an important risk factor of abortion and stillbirth in cattle. The present results showed that T. gondii and N. caninum infections might be a risk for public health and economy of the livestock industry in Mongolia. In conclusion, this study demonstrates high seroprevalences of T. gondii and N. caninum in Mongolia and provides valuable new data for development of control measures against these infections in Mongolia.

The method matters: The effect of handling time on cortisol level and blood parameters in wild cats

Blood analysis has recently become a popular tool to assess the welfare of the wild cats. However, the estimates of blood parameters may depend on the sampling method. We have tested (1) if the sampling procedure influences blood parameters and (2) what parameters are the most efficient in assessing the physiological status in wild cat species. We assessed the effect of handling time on red blood cells (RBC) and white blood cells (WBC) counts, the ratio of neutrophils to lymphocytes (N/L ratio), and serum cortisol level within 1 hr after the capture of the animal in six far-east wild cats (Prionailurus bengalensis euptilura). Also, we analyzed literature data in 17 cat species to assess the effect of place of study, type of immobilization, and handling time on WBC count and N/L ratio. Serum cortisol level varied significantly with the handling time. RBC and WBC counts were strongly affected by the handling time. N/L ratio was very robust and did not depend on the handling time. However, the analysis of literature data has shown that the prolonged handling time (over 1 hr) and the type of immobilization significantly influence the N/L ratio, whereas the WBC count does not depend on any of considered factors. We conclude that while most blood parameters of cats are affected by routine handling time, the N/L ratio does not vary if the samples are collected within 1 hr after the capture of the animal. All other tested parameters should be treated with caution.

Captivity influences immune responses, stress endocrinology, and organ size in house sparrows (Passer domesticus)

Studies using wild animals in laboratory-based research require bringing wild-captured organisms into a novel setting, which can have long-lasting impacts on physiology and behavior. In several species, captivity stimulates stress hormone production and can alter immune function. Despite this, there is little consensus on how captivity influences stress hormone regulation, or if captivity-induced changes in stress hormone production and regulation mediate changes in immune function. In this study, we investigate the influence of captivity on the physiology of a wild bird commonly-used in laboratory-based research, the house sparrow (Passer domesticus). We tested how captivity influences stress endocrinology, immune responses, and organ mass, and also investigated if the production or regulation of corticosterone, the main stress hormone in birds, correlated with changes in immunity. We found that baseline corticosterone concentrations and maximum capacity of the adrenals to secrete corticosterone increase following captivity and remain elevated after 9weeks of captivity. A measure of innate immune function, the bactericidal ability of plasma, also increased with time spent in captivity. Wound healing was also influenced by time spent in captivity, with birds taking almost 2days longer to heal if they were wounded after 3weeks in captivity when compared with birds that were wounded immediately upon capture. Additionally, captivity caused notable reductions in spleen and liver mass. Together, these results imply that captivity can have long-lasting effects on house sparrow corticosterone release and immune function, and suggest that even after 9weeks house sparrows do not acclimate physiologically to life in captivity.

Image-based red blood cell counter for multiple species of wild and domestic animals

ABSTRACT RBC count plays an important role in animal diagnosis. Despite the many technologies available in different automated hematology analyzers, when it comes to the blood of wild animals it is still difficult to find an easy and affordable solution for multiple species. This study aims to evaluate the proposed automatic red blood cell counter. Blood samples (1 ocelot - Leopardus pardalis, 1 monkey - Cebus apella, 1 coati - Nasua nasua, 62 dogs - Canis familiaris, and 5 horses - Equus caballus) were analyzed using three methods: 1-manual count, 2-automatic count by image, and 3-semi-automatic count by image; blood from dogs and horses were also analyzed by a fourth method: 4-automatic count by impedance. The counts in methods 2 and 3 were produced by the proposed red blood cell counter. Results were compared using Pearson's correlation and plots with different methods as the criterion standard. RBC counts in methods 1, 2, and 3 correlated very well with those in the method 4 (r ≥ 0.94). RBC counts produced by method 2 were highly correlated with method 3 (r = 0.998). The results indicate that the proposed method can be used as an automatic or semi-automatic counting method in clinics that are currently using the manual method for RBC assessment.

First record and molecular identification of Toxocara cati in a Pallas’ cat Otocolobus manul from Kyrgyzstan

In the present paper, we the report the first documented occurrence in the wild of Toxocara cati in the sole representative of the genus Otocolobus, the Pallas’ cat. The identity of the parasite was confirmed by morphological characteristics and by genetic barcoding of the second internal transcribed spacer of ribosomal DNA. The morphological measures of the T. cati specimens from the Kyrgyz Pallas’ cat were comparable to values reported. We discuss the conservation implication of our find.

An Immunohistochemical and Polymerase Chain Reaction Evaluation of Feline Plasmacytic Pododermatitis

Sections of 14 skin biopsies of cats with plasmacytic pododermatitis and a clinical follow-up of 12–36 months were stained with a polyclonal anti- Mycobacterium bovis (Bacille Calmette-Guerin = BCG) antibody cross-reactive to a broad spectrum of fungi and bacteria. All sections were negative for organisms within the actual footpad tissue with the anti-BCG antibody stains. Polymerase chain reaction (PCR) assays that amplify the DNA of Bartonella spp., Ehrlichia spp., Anaplasma phagocytophilum, Chlamydophila felis, Mycoplasma spp., Toxoplasma gondii, and feline herpesvirus 1 (FHV-1) were applied to tissue digests. DNA of those pathogens assessed was not amplified from tissue.

Patterns of seroprevalence of feline viruses among domestic cats (Felis catus) and Pallas’ cats (Otocolobus manul) in Daursky Reserve, Russia

Few data are available on the prevalence of feline viruses in the wild and little is known about natural sources of infections. The aim of this study was to estimate patterns of seroprevalence to feline viruses (feline immunodeficiency virus (FIV), feline calicivirus (FCV), feline panleukopenia virus (FPV), feline herpesvirus (FHV), and feline leukemia virus (FeLV)) in two cat species, domestic cats (Felis catus L., 1758) (n = 61) and Pallas’ cats (Otocolobus manul (Pallas, 1776)) (n = 24), living in the same area, in Daursky Reserve, Russia. Our results indicate that four of five viruses are circulating in the study area, with the exception of FHV. The pattern of FCV and FPV prevalence differed from FIV and FeLV. FCV and FPV seroprevalence did not depend on the sex and predominated in the group of cats living in the village (76% and 55%, respectively). No Pallas’ cats were seropositive to these viruses. The prevalence of FIV and FeLV were similar in areas with different cat densities (at the stations (16% for both viruses) and in the village (16% for both viruses)). The patterns of seroprevalence between species testify to the low rate of interspecific contacts. In Pallas’ cats, we found the presence of antibodies to FIV to be 5% and antigens of FeLV to be 5%, pathogens for which transmission demand close direct contacts between animals (mainly aggressive and (or) sexual contact), which is typical in the breeding season. Arid climate may also reduce patterns of viral prevalence in the study area, decreasing the risk of infection for both cat species.

Does immune suppression during stress occur to promote physical performance?

Two adaptationist hypotheses have been proposed to explain why stress, particularly elevation of stress hormones (i.e., glucocorticoids), tends to suppress immune functions. One is that immune suppression represents efforts to minimize autoimmune responses to self-antigens released as organisms cope with stressors (i.e., the autoimmune-avoidance hypothesis). The other is that immune suppression occurs to promote a shunting of resources to life processes more conducive to survival of the stressor (i.e., the re-allocation hypothesis). Here in wild-caught house sparrows (Passer domesticus), we tested the second hypothesis, asking whether sustained elevation of baseline glucocorticoids, due to captivity, caused a greater rate of decline in immune functions than flight performance. A greater decline in immune functions than flight performance would support the re-allocation hypothesis. As in previous studies, we found that captivity tended to alter baseline corticosterone, suggesting that house sparrows experience captivity as a stressor. Captivity also affected several constitutive and induced innate immune metrics: bacterial (Escherichia coli) killing activity (BKA) of blood and oxidative burst of leukocytes both changed in a manner consistent with immune disregulation. In contrast, breast muscle size and vertical flight (hovering) duration improved over captivity. Collectively, these changes provide indirect support for the re-allocation hypothesis, although within individuals, changes in immune and physical performance were unrelated.

Residues in Brandt's voles (Microtus brandti) exposed to bromadiolone-impregnated baits in Mongolia

In 2002, hundreds of non-target wildlife deaths occurred in Mongolia following aerial applications of bromadiolone, an anticoagulant rodenticide, to control eruptive Brandt's vole (Microtus brandti) populations. To clarify whether secondary poisoning could have contributed to these deaths, a field study was undertaken in Mongolia to measure bromadiolone residues in voles following exposure to two concentrations (50 and 500 mg/kg) of bromadiolone-treated wheat. The two treatments produced different total burdens (2.65 microg+/-0.53SE and 13.70 microg+/-3.82SE, respectively) and liver burdens (1.74 microg+/-0.33SE and 8.81 microg+/-2.33SE, respectively) of bromadiolone in voles (both p<0.05). Total burdens of bromadiolone in voles found dead above ground were higher than those of live-trapped voles (32.35 microg+/-17.98SE versus 5.18 microg+/-1.40SE, respectively; p<0.05). These results are valuable for future assessments of secondary poisoning risk to scavengers and predators from large-scale bromadiolone poisoning operations of the type undertaken in Mongolia.

Feline immunodeficiency virus (FIV) in wild Pallas' cats

Feline immunodeficiency virus (FIV), a feline lentivirus related to HIV, causes immune dysfunction in domestic and wild cats. The Pallas' cat is the only species from Asia known to harbor a species-specific strain of FIV designated FIV(Oma) in natural populations. Here, a 25% seroprevalence of FIV is reported from 28 wild Mongolian Pallas' cats sampled from 2000 to 2008. Phylogenetic analysis of proviral RT-Pol from eight FIV(Oma) isolates from Mongolia, Russia, China and Kazakhstan reveals a unique monophyletic lineage of the virus within the Pallas' cat population, most closely related to the African cheetah and leopard FIV strains. Histopathological examination of lymph node and spleen from infected and uninfected Pallas' cats suggests that FIV(Oma) causes immune depletion in its' native host.