Seroprevalence of Toxoplasma gondii in Wild Toque Macaques (Macaca sinica) at Polonnaruwa, Sri Lanka

The Influence of Landscape Structure on the Occurrence of Neospora caninum, Toxoplasma gondii, and Sarcocystis spp. in Free-Living Neotropical Primates

PURPOSE

Habitat fragmentation is the main threat to primate survival in the world. Additionally, changes in the environments in which they live can also contribute to exposure to pathogens. To investigate some pathogens that free-living primates may be exposed to in Rio Grande do Sul State (RS; southern Brazil) and characterize the forest remnants in which they live, we investigated anti-Neospora caninum, Toxoplasma gondii, and Sarcocystis spp. antibodies in the serum of the animals.

METHODS

We analyzed 105 serum samples from 63 black howler monkeys (Alouatta caraya), 39 southern brown howler monkeys (Alouatta guariba clamitans), and 03 capuchin monkeys (Sapajus nigritus cucullatus), which were captured in forest fragments of RS. Indirect fluorescence antibody test (IFAT) and indirect hemagglutination assay (IHA) were used to detect antibodies to the agents. We then characterized the landscapes in a multiscale approach in radii from 200 to 1400 m to investigate the relationship of the presence of the agents with landscape elements.

RESULTS

In the IFAT-IgG, 13.3% (14/105) of the samples were seropositive for N. caninum, 4.8% (5/105) for T. gondii, and 5.7% (6/105) for Sarcocystis spp. In the IHA-IgM/IgG, 24.8% (26/105) were seropositive for T. gondii. The metrics that best explained exposure to agents were edge and patch density, forest cover, urban cover, and average Euclidean distance to the nearest patch.

CONCLUSIONS

This study indicated that the primates were exposed to the agents studied, demonstrating that some landscape features are associated with exposures to the investigated pathogens.

Gastrointestinal parasites of six large mammals in the Wasgomuwa National Park, Sri Lanka

Gastrointestinal (GI) parasites may impose detrimental consequences on wildlife populations due to their capacity to cause mortality and reduce fitness. Additionally, wild animals play an important role in the transmission of zoonoses. Despite this importance, information on GI parasites of tropical wild mammals is critically lacking. The present study aimed to document GI parasites of six wild-dwelling large mammal taxa in Sri Lanka: Asian elephant (Elephas maximus), Sloth bear (Melursus ursinus), civet (Paradoxurus sp.), Leopard (Panthera pardus), Grey langur (Semnopithecus priam) and buffalo (Bubalus sp). Fresh faecal samples (n = 56) collected from the Wasgomuwa National Park, Sri Lanka were subjected to coprological examination using faecal smears, and the brine floatation technique followed by microscopic identification; quantitative data were accrued using the formol-ether method. The survey revealed a high prevalence of GI parasites, where 86% (48/56) of faecal samples screened positive for parasitic infections. Faecal samples of the civet, buffalo and Leopard recorded 100% prevalence, while the lowest (40%) was recorded for the Grey langur. Eight types of GI parasites were documented: protozoan cysts, platyhelminth ova (three types of digenean and a single cyclophillidean type), nematode ova (strongyle, strongyloid, ascarid, and trichuroid types) and rhabditiform larvae. The buffaloes and civets had a comparatively high number and diversity of GI parasites (buffalo: 7 types, H’ = 1.02; civet: 6 types, H’ = 1.52), whilst only a single type (digenean) was detected in the Grey langur. Likewise, parasite loads were also highly variable; highest in the bear (486 per g faeces) and lowest in the monkey (10 per g faeces). The outcome of this survey is important on two accounts; i) to fill the knowledge gap on GI parasites of tropical wild mammals, and ii) the revelation of many first-time parasite-host records for some of the threatened wild-dwelling large mammals in Sri Lanka.

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GI parasites of six native large mammals from the wild recorded from Sri Lanka.

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Novel GI parasite records of locally and globally endangered large mammals reported.

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High prevalence (86%) of infected fecal samples; eight GI parasite types identified.

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Buffaloes and civets had high parasite diversity; highest parasite load in the Sloth bear.

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GI parasite diversity and prevalence differed between wild and captive mammals.

Effect of urbanization on zoonotic gastrointestinal parasite prevalence in endemic toque macaque (Macaca sinica) from different climatic zones in Sri Lanka

Understanding variations in host-parasite relationships with urbanization is vital for both, public health management and conservation of endemic animals with high anthropogenic interactions. Toque macaques (Macaca sinica) are such endemic old-world monkeys in Sri Lanka. Three macaque sub species inhabit the main climatic zones of the island; M . s. sinica , M . s. aurifrons and M . s. opisthomelas inhabit the dry zone, wet zone, and montane regions of the island, respectively. This study aimed to examine parasite prevalence in this host in association with urbanization. A total of 180 fecal samples were collected from the three sub species of toque macaques inhabiting the main climatic zones (dry, wet, and montane) in Sri Lanka; 20 samples each were collected from urban, suburban, and wild populations representing each climatic zone. Twenty gastrointestinal (GI) parasite genera types i.e. five types of protozoan cysts, two types of trematode ova, four types of cestode ova, eight types of nematode ova, and a single type of acanthocephalan ova were identified. The overall prevalence of parasites was 62% (112/180) with the highest prevalence of Strongyloides infection. In all three sub species, toque macaque populations with proximity to human settlements, including urban and suburban populations, manifested a greater GI parasitic prevalence, mean ova/cyst counts and species richness, compared to their wild counterparts. Importantly, records of five parasite types in toques in Sri Lanka are reported for the first time, while Moniliformis type was reported as a first record in free ranging macaques, globally. This study clearly demonstrated that human contact and habitat modification may influence patterns of parasitic infections in macaques. As most of the parasite types identified manifest zoonotic potential, with public health implications, close associations of macaques may cause a threat to human well-being.

Gastro-intestinal parasites in two subspecies of toque macaque (Macaca sinica) in Sri Lanka and their zoonotic potential

Gastro-intestinal (GI) parasites of primates have a greater potential of becoming zoonotic. This potential may vary in different primates based on multiple factors such as proximity to human settlements and the climate of their habitat. We examined the GI parasites in two subspecies of toque macaque: Macaca sinica sinica (confined to the dry zone) and Macaca sinica aurifrons (confined to the wet zone) of Sri Lanka. Fresh faecal samples were collected and analysed following a modified Sheather's sucrose floatation method. A total of 90.8% (89/98) macaques were infected with one or more parasite species. There was no difference in the overall prevalence of GI parasites between the two subspecies, M. s. aurifrons (95.9%) and M. s. sinica (85.7%; χ²;χ = 3.059, p = 0.080). Sixteen parasite species were recorded including, 15 species in the M. s. sinica and 12 species in the M. s. aurifrons. Among the helminths identified, Anatrichosoma sp., Ancylostoma spp., Capillaria spp., Oesophagostomum /Bunostomum spp. and Physaloptera spp. are known to be zoonotic while Ascaris spp., Enterobius sp., Strongyloides spp. and Trichuris spp. have both zoonotic and anthroponotic potential. Among the protozoans, Balantidium coli and Buxtonella sp. are known to be zoonotic, while Entamoeba spp. and Cryptosporidium spp. have both anthroponotic and zoonotic potential. This study provides the first record of Anatrichosoma sp. and Buxtonella sp. in Sri Lanka and the first record of Cryptosporidium spp. in M. s. aurifrons. The molecular data allowed further identification and differentiation of Entamoeba nuttalli and E. coli that are known to be zoonotic and anthroponotic, respectively. The two subspecies of macaques have close interactions with humans; hence, in-depth epidemiological studies are required to understand the potential public-health risks to humans and conservation implications for macaque populations.

Environmental factors associated With Toxoplasma gondii Exposure in Neotropical Primates of Costa Rica

The apicomplexan parasite Toxoplasma gondii (T. gondii) has been found in more than 350 species of homoeothermic vertebrates in diverse climates and geographic areas. In most animals, T. gondii produces mild or asymptomatic infection. However, acute and hyperacute toxoplasmosis is associated with high mortality rates observed in Neotropical primates (NP) in captivity. These primates are distributed in 20 countries across the Americas, and although infection has been reported in certain countries and species, toxoplasmosis in the wild and its impact on NP population survival is unknown. Differences among species in exposure rates and disease susceptibility may be due in part to differences in host behavior and ecology. Four species of NP are found in Costa Rica, i.e., howler (Alouatta palliata), spider (Ateles geoffroyi), capuchin (Cebus imitator), and squirrel monkeys (Saimiri oerstedii). This study reports NP exposure to T. gondii using the modified agglutination test in 245 serum samples of NP (198 wild and 47 from captivity) from Costa Rica. Associations of serostatus with environmental (forest cover, annual mean temperature), anthropogenic (human population density), and biological (sex) variables in howler and capuchin monkeys were evaluated. The seroprevalence among wild NP was 11.6% (95% CI = 7.7–17.34), compared with 60% in captive monkeys (95% CI = 44.27–73.63), with significant differences between species (X² = 20.072; df = 3, p = 0.000164), suggesting an effect of behavior and ecology. In general, antibody titers were low for wild NP (<1:128) and high for captive NP (>1:8192), suggesting higher exposure due to management factors and increased life span in captivity. Seropositivity in howler monkeys was positively related to forest cover and inversely related to annual rainfall. For capuchins, annual rainfall was inversely related to seropositivity. Surveillance of T. gondii exposure in NP in captivity and in the wild is required to understand drivers of the infection and develop novel strategies to protect them.

Isolation and Molecular Characterization of Entamoeba nuttalli Strains Showing Novel Isoenzyme Patterns from Wild Toque Macaques in Sri Lanka

We have proposed the revival of the name Entamoeba nuttalli for a virulent ameba strain, P19-061405, from a rhesus macaque and located it phylogenetically between E. histolytica and E. dispar. As E. nuttalli was originally described for an ameba found in a toque macaque in Sri Lanka, the prevalence and characteristics of Entamoeba species in wild toque macaques were examined. PCR analysis of 227 stool samples from six locations showed positive rates for E. nuttalli, E. dispar, and E. histolytica of 18.5%, 0.4%, and 0%, respectively. Fifteen E. nuttalli strains were cultured successfully from five locations. The 18S ribosomal RNA gene showed only three nucleotide differences in comparison with P19-061405 strain. In isoenzyme analysis, the pattern of hexokinase in Sri Lankan strains was different from that of P19-061405 strains and the difference was confirmed by analysis of the genes. Hepatic inoculation of one of the Sri Lankan E. nuttalli strains in hamsters resulted in amebic abscess formation and body weight loss. These results demonstrate that E. nuttalli is prevalent in wild toque macaques and that several characteristics of the strains are unique. We conclude that use of the name E. nuttalli is appropriate for the new Entamoeba species found in nonhuman primates.

First report of Toxoplasma gondii seroprevalence in wild-caught Caribbean African green monkeys

BACKGROUND

Toxoplasma gondii is a protozoan parasite capable of infecting all warm-blooded animals. Humans can become infected by ingesting infective oocysts from the environment or contaminated food or water, or by ingesting tissue cysts in undercooked infected meat or by handling infected meat. Caribbean African green monkeys (Chlorocebus sabaeus) are present in large numbers on the island of St. Kitts in the Caribbean, and it is not uncommon for these animals to be trapped and eaten by islanders. The aim of this study was to determine T. gondii infection in Caribbean African green monkeys.

FINDINGS

Sera collected from 79 wild-caught Caribbean African green monkeys were examined for T. gondii antibodies by ELISA. Antibodies were detected in 38 out of 79 (48.1%) monkeys. Significantly more females were infected than males but there was no significant effect of age or location on antibody status.

CONCLUSIONS

Results indicate that Caribbean African green monkeys can be infected with T. gondii and that there is widespread environmental contamination of St. Kitts with oocysts. These monkeys could present a potential source of T. gondii infection if their meat is consumed undercooked. This is the first report of T. gondii antibodies in this species.

Beyond the disease: Is Toxoplasma gondii infection causing population declines in the eastern quoll (Dasyurus viverrinus)?

Disease is often considered a key threat to species of conservation significance. For some, it has resulted in localised extinctions and declines in range and abundance. However, for some species, the assertion that a disease poses a significant threat of extinction is based solely on correlative or anecdotal evidence, often inferred from individual clinical case reports. While a species' susceptibility to a disease may be demonstrated in a number of individuals, investigations rarely extend to measuring the impact of disease at the population level and its contribution, if any, to population declines. The eastern quoll (Dasyurus viverrinus) is a medium-sized Australian marsupial carnivore that is undergoing severe and rapid decline in Tasmania, its last refuge. Reasons for the decline are currently not understood. Feral cats (Felis catus) may be undergoing competitive release following the ongoing decline of the Tasmanian devil (Sarcophilus harrisii), with cats suppressing eastern quolls through increased predation, competition, exclusion or exposure to diseases such as toxoplasmosis. To investigate the effects of Toxoplasma gondii infection, eastern quoll populations at four sites were regularly screened for the seroprevalence of T. gondii-specific IgG antibodies. Seroprevalence was approximately five times higher at sites with declining quoll populations, and there was a negative association between seroprevalence and quoll abundance. However, T. gondii infection did not reduce quoll survival or reproduction. Despite a high susceptibility to T. gondii infection, eastern quoll populations do not appear to be limited by the parasite or its resultant disease. Significantly higher seroprevalence is a signal of greater exposure to feral cats at sites where eastern quolls are declining, suggesting that increased predation, competition or exclusion by feral cats may be precipitating population declines.

Regional seroprevalence of Toxoplasma gondii antibodies in feral and stray cats (Felis catus) from Tasmania

Toxoplasma gondii is a cosmopolitan protozoan parasite of felids that also has significant implications for the health of wildlife, livestock and humans worldwide. In Australia, feral, stray and domestic cats (Felis catus) are the most important definitive host of T. gondii as they are the only species that can excrete the environmentally resistant oocysts that provide a major source of infection for mammals and birds. In Tasmania, the rapid decline of the Tasmanian devil (Sarcophilus harrisii) may allow an increase in feral cat abundance, thereby increasing the risk of T. gondii infection to a range of susceptible wildlife species. At present, there is scant information on the prevalence of T. gondii infection in feral cat populations across Tasmania. We tested feral cats from 13 regions across Tasmania for the presence of T. gondii–specific IgG antibodies using a modified agglutination test. Results were combined with serosurveys from three previous studies to enable a comparison of seroprevalence among 14 regions across Tasmania. We found that 84.2% (224 of 266) of cats tested positive for T. gondii IgG antibodies. This is among the highest rates of prevalence recorded from Australia, and significantly higher than for most other countries. Adult cats had higher seroprevalence than kittens but there was no difference between sexes. In Tasmania, seroprevalence was high in 12 of 14 regions (range: 79.3–100.0%), with only two regions (Tasman Island and Southern Tasmania) recording significantly lower seroprevalence (≤50%). This suggests a high risk of infection across Tasmania, and has significant implications for wildlife conservation should feral cat abundance increase with the ongoing declines in Tasmanian devils.

Frequency of Toxoplasma gondii antibodies in tufted capuchin monkeys (Cebus apella nigritus) from an ecological station in the State of São Paulo, Brazil

Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, an obligate intracellular parasite protozoan. A large percentage of animals presents specific antibodies caused by a previous exposition, resulting in a chronic infection. Felides are the definitive hosts and the other warm-blooded animals, including primates, are the intermediate hosts. This study was aimed to determine the prevalence of T. gondii infection in free-living tufted capuchin monkeys (Cebus apella nigritus) from an ecological station located on Mata de Santa Teresa, Ribeirão Preto, SP, Brazil. T. gondii antibodies were analyzed by modified agglutination test (MAT) in serum samples of 36 tufted capuchin monkeys, considering eight as cut-off titer. From the studied animals, 3/36 (8.33%; CI95% 3.0-21.9%) presented T. gondii antibodies, all with titer 32. No significative difference was observed relating to the sex (1/3 male and 2/3 female), and to the age (1/3 young and 2/3 adult) (P>0.05). Thus, these results demonstrate the presence of T. gondii antibodies in primates from São Paulo state.

Infection by Toxoplasma gondii in Neotropical non-human primates

Toxoplasma gondii (Nicolle et Manceaux, 1909) is an obligatory intracellular protozoan parasite of warm animals, including human and non-human primates. Domestic and wild felids are considered definitive hosts. Several authors have already identified lesions in New World primates caused by T. gondii. Nevertheless, little is known about serological studies on those animals. With this reason, New World non-human primates of the genera Cebus and Callithrix that were apprehended by governmental authorities and sent to the Wildlife Screening Center (Cetas)/IBAMA, at the municipality of Seropédica, state of Rio Janeiro, were bled and sera were submitted to the indirect hemagglutination test for detection of anti-T. gondii antibodies. From 21 sera of Cebus primates, 76.19% (16/21) had anti-T. gondii antibodies. Titles varied from 16 to 2048. In samples from 21 Callithrix, only 4.5% (1/22) had anti-T. gondii antibodies. Only one animal had a title of 32. During all the time those animals were clinical evaluated until sample was collected; none of them had any clinical sign or sequel related to infection by T. gondii. The fact that the origin of these primates is unknown and that there is no information about their feeding habits before captivity makes it difficult to determine the source of T. gondii infection.

Macaque models of human infectious disease

Macaques have served as models for more than 70 human infectious diseases of diverse etiologies, including a multitude of agents—bacteria, viruses, fungi, parasites, prions. The remarkable diversity of human infectious diseases that have been modeled in the macaque includes global, childhood, and tropical diseases as well as newly emergent, sexually transmitted, oncogenic, degenerative neurologic, potential bioterrorism, and miscellaneous other diseases. Historically, macaques played a major role in establishing the etiology of yellow fever, polio, and prion diseases. With rare exceptions (Chagas disease, bartonellosis), all of the infectious diseases in this review are of Old World origin. Perhaps most surprising is the large number of tropical (16), newly emergent (7), and bioterrorism diseases (9) that have been modeled in macaques. Many of these human diseases (e.g., AIDS, hepatitis E, bartonellosis) are a consequence of zoonotic infection. However, infectious agents of certain diseases, including measles and tuberculosis, can sometimes go both ways, and thus several human pathogens are threats to nonhuman primates including macaques. Through experimental studies in macaques, researchers have gained insight into pathogenic mechanisms and novel treatment and vaccine approaches for many human infectious diseases, most notably acquired immunodeficiency syndrome (AIDS), which is caused by infection with human immunodeficiency virus (HIV). Other infectious agents for which macaques have been a uniquely valuable resource for biomedical research, and particularly vaccinology, include influenza virus, paramyxoviruses, flaviviruses, arenaviruses, hepatitis E virus, papillomavirus, smallpox virus, Mycobacteria, Bacillus anthracis, Helicobacter pylori, Yersinia pestis, and Plasmodium species. This review summarizes the extensive past and present research on macaque models of human infectious disease.

Seroprevalence of Toxoplasma gondii antibodies in captive elephants (Elephaus maximus maximus) in Sri Lanka

Serum samples collected during August 2003-June 2004 from 45 privately owned captive and 8 elephants from the Pinnawala Elephant Orphanage were tested for the presence of antibodies against Toxoplasma gondii using the direct modified agglutination test (MAT). Antibodies were found in sera of 14 of 45 (32%) privately owned elephants with titers of 1:25 in three, 1:50 in three, 1:100 in three, 1:200 in three, and 1:400 in three elephants. The elephants from Pinnawala Elephant Orphanage were seronegative. This is the first report of T. gondii seroprevalence in elephants in Sri Lanka.

Sero-epidemiological survey for toxoplasmosis in wild New World monkeys (Cebus spp.; Alouatta caraya) at the Paraná river basin, Paraná State, Brazil

In this study, we captured 60 wild New World monkeys (Cebus spp.; Alouatta caraya) at the Paraná river basin, Paraná State, Brazil, and modified agglutination test (MAT) was performed to evaluate anti-Toxoplasma gondii antibodies. Prevalence was 30.2% (13/43) in Cebus spp. (capuchin monkeys) and 17.6% (3/17) for A. caraya (black and golden howler monkeys). MAT showed antibody titers of 16 (15/16) and 64 (1/16). Herein, we have observed an odds ratio (OR)=4.67 (1.06<OR<21.42, p<0.01) among monkeys with presumed risk of human contact. There were not any statistical differences among age, species and sex (p>0.05). The present work is the first report on serum occurrence of anti-T. gondii antibodies in wild capuchin monkeys and in wild black and golden howler monkeys.