Seroprevalence of Toxoplasma gondii in captive felids in Thailand

Detection of zoonotic enteropathogens in captive large felids in Italy

AIMS

Within the One Health paradigm, infectious disease surveillance have been developed for domestic and wild animals, leaving the role of captive non-domestic populations, especially felids in zoos and circuses, less explored. This study addresses the proximity of these captive animals to urban areas, necessitating focused monitoring for potential zoonotic enteropathogens. The present work aimed to investigate the presence of such zoonotic enteropathogens in faecal samples from captive large felid populations.

METHODS AND RESULTS

A total of 108 faecal samples were collected in three circuses, five zoos and one rescue centre across Italy. Salmonella spp. isolation, serotyping and antimicrobial susceptibility testing were conducted on all samples. Additionally, 60 samples were also examined for gastrointestinal parasites using standard coprological techniques. Giardia spp. detection employed direct immunofluorescent staining and specific PCR, while Toxoplasma gondii was detected using PCR targeting B1 gene. A total of 51 Salmonella enterica subsp. enterica were isolated, with predominant serovariants including Infantis (43.1%), Coeln (11.8%) and Newport (11.8%). The captive felids likely act as asymptomatic carriers of foodborne Salmonella, with notable resistance ampicillin and trimethoprim-sulfamethoxazole, no resistance to enrofloxacin was noted. Microscopic analysis revealed Toxascaris leonina eggs in 11 faecal samples (18.3%) and Giardia duodenalis cysts in one animal (1.7%).

CONCLUSIONS

Captive animals in public settings may act as sources of Salmonella infection and enteroparasitosis for both occupational and general exposure. The study emphasizes the role of captive animals in antimicrobial resistance dynamics, highlighting the need for routine pathogen screening in the management practices of zoological structures.

Serological survey of Toxoplasma gondii infection in cats in Khon Kaen, Northeast Thailand

Background and Aim: Toxoplasmosis is a zoonosis caused by Toxoplasma gondii. Cats are known to be the definitive hosts that can excrete these environmentally resistant oocysts. Other mammals, avians, and even humans can serve as the intermediate host. T. gondii infection is often asymptomatic in healthy individuals; however, it could result in serious health problems in immunocompromised and pregnant individuals. This study investigated the occurrence of T. gondii infection in cats in Khao Suan Kwang and Mueang Khon Kaen. Materials and Methods: In total, 100 serum samples from cats, that is, 62 owned cats (31 males and 31 females) and 38 adopted stray cats (21 males and 17 females), were examined for antibodies against T. gondii through rapid immunochromatographic tests (ICT). Owners were asked to sign a consent form and answer the questionnaires before sample collection. Demographic information about the cats and their owners was also recorded. Results: The overall seroprevalence of cats positive for T. gondii antibodies was found to be 5%. Notably, the Toxoplasma antibody prevalence was significantly higher in the adopted stray cats (10.53% [4/38]) that roamed the zoo than in the owned cats (1.61% [1/62]) (p > 0.05). No significant difference was observed between male (8.33%) and female (1.92%) cats. The cat owners' questionnaire revealed that more than half had never heard of toxoplasmosis before (67.7%), whereas 30.6% knew nothing about the disease transmission routes. Conclusion: This study presented a low seroprevalence of antibodies to T. gondii in owned cats from the Mueang Khon Kaen District, whereas high seroprevalence was detected in the adopted stray cats from Khao Suan Kwang. Adopted stray cats can have a higher potential for T. gondii infection; thus, they could be a source of toxoplasmosis transmission to humans. Therefore, it is essential to control the number of stray cats, and a screening test for antitoxoplasmosis could be recommended before adoption. Although the total seroprevalence was noted to be low, the zoonotic disease was present. Therefore, raising the community's awareness and knowledge might reduce the disease transmission from animals to humans.

Exposure to Toxoplasma gondii in Asian Elephants (Elephas maximus indicus) in Thailand

Toxoplasma gondii is the causative agent of toxoplasmosis in humans and various animal species worldwide. In Thailand, seroprevalence studies on T. gondii have focused on domestic animals, and information on infections in Asian elephants (Elephas maximus indicus) is scarce. This study was conducted to determine the seroprevalence of T. gondii infection in archival sera collected from 268 elephants living in Thailand. The serum samples were analyzed for anti-T. gondii immunoglobulin G antibodies using the latex agglutination test (LAT) and indirect enzyme-linked immunosorbent assay (iELISA) based on T. gondii lysate antigen (TLA-iELISA) and recombinant T. gondii dense granular antigen 8 protein (TgGRA8-iELISA). The prevalence of antibodies against T. gondii was 45.1% (121/268), 40.7% (109/268), and 44.4% (119/268) using LAT, TLA-iELISA, and TgGRA8-iELISA, respectively. Young elephants had a higher seropositivity rate than elephants aged >40 years (odds ratio = 6.6; p < 0.001; 95% confidence interval: 2.9–15.4). When LAT was used as the reference, TLA-iELISA and TgGRA8-iELISA showed a substantial (κ = 0.69) and moderate (κ = 0.42) agreement, respectively. Although our findings suggest the widespread exposure of Asian elephants to T. gondii in Thailand, the source of infection was not investigated. Therefore, investigation of the predisposing factors associated with toxoplasmosis is necessary to identify the potential risk factors for infection.

Prevalence and diversity of gastrointestinal parasites in free-ranging rhesus macaques (Macaca mulatta) in different land gradients of Bangladesh

Rhesus macaques are considered an important reservoir of different gastrointestinal (GI) zoonotic parasites affecting livestock and humans. Loads of GI parasites in the free-ranging rhesus macaques living in close proximity to communities in Bangladesh are still unknown. To estimate the prevalence and diversity of zoonotic GI parasites in rhesus macaques of Bangladesh, a total of 182 freshly voided fecal samples were collected from macaques living in rural (N = 67), peri-urban (N = 57), urban (N = 28), and Safari park (N = 30) between October 2015 and December 2016. All samples were tested by direct smear, sedimentation, flotation, and the McMaster techniques. A total of fourteen different taxa of GI parasites were detected, revealing an overall prevalence of 54.4% (n = 99; 95% confidence interval [CI]: 46.9-61.8). The prevalence of GI parasites was found to be significantly correlated with the mean parasitic taxa per individual in a group (r = 0.90; p = 0.002). The multivariable logistic regression analysis showed that the overall prevalence of GI parasites in macaques was significantly higher in those inhabiting rural areas (62.69%; odds ratio [OR]: 7.22; p = 0.001) and in macaques with interactions with other animals (60.98%; OR: 5.49; p = 0.005). Our results also indicated that the prevalence of Strongyloides spp. and Balantidium coli infections varied significantly between land gradients. Our results also indicate that macaques frequently visit human settlements for food and are found interacting with domestic animals. In conclusion, the high prevalence of zoonotic GI parasite infection in rhesus macaques found in our study may pose a significant public health risk to communities, particularly in rural areas of Bangladesh. Health promotion to at-risk communities focusing on limiting contact with rhesus macaques is necessary to mitigate potential zoonotic transmission.

The global serological prevalence of Toxoplasma gondii in felids during the last five decades (1967-2017): a systematic review and meta-analysis

Background

Felids (domestic and wild cats) are important in the epidemiology of the parasite Toxoplasma gondii because they are the only hosts that can excrete the environmentally resistant oocysts. We conducted a systematic review and meta-analysis to estimate the global prevalence of T. gondii in species of the family Felidae.

Methods

We searched seven databases (PubMed, Embase, Google Scholar, ScienceDirect, Scopus, Proquest and Web of Science) for studies reporting seroprevalence of T. gondii in felids from 1967 to 31 December 2017. A total of 217 published papers, containing 223 datasets were eligible for inclusion in the meta-analysis, comprised 59,517 domestic and 2733 wild cats from 1967 to 2017.

Results

The pooled global T. gondii seroprevalence was estimated to be 35% (95% CI: 32–38%) and 59% (95% CI: 56–63%) in domestic cats and wild felids, respectively, using random effects model. The seroprevalence was higher in Australia and Africa where the T. gondii seropositivity in domestic cats was 52% (95% CI: 15–89%) and 51% (95% CI: 20–81%), respectively. The lowest seroprevalence was estimated in Asia 27% (95% CI: 24–30%). The seroprevalence values for T. gondii in wild felids were 74% (95% CI: 62–83%) in Africa, 67% (95% CI: 23–111%) in Asia, 67% (95% CI: 58–75%) in Europe and 66% (95% CI: 41–91%) in South America.

Conclusions

Our study provides the global prevalence of T. gondii in species of the family Felidae and is a source of information to aid public health workers in developing prevention plans.

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 .

Isolation, genotyping and pathogenicity of a Toxoplasma gondii strain isolated from a Serval (Leptailurus serval) in China

Toxoplasma gondii typically causes lifelong chronic infection and has been identified in a variety of intermediate and definitive hosts. Felids are capable of serving as both intermediate and definite hosts for T. gondii infection. However, there is no direct evidence to prove that servals are the intermediate host of T. gondii. In this study, T. gondii antibodies were detected in a serval by a modified agglutination test (titer, 1:200). Viable T. gondii was isolated from the striated muscles of the serval. This strain was further propagated in cell culture and designated as TgServalCHn1. Genetic characterization of DNA derived from cell culture was performed by RFLP-PCR of 10 markers, as well as polymorphic ROP5 and ROP18 genes. Results showed that this strain of T. gondii belonged to the genotype ToxoDB#20. The ROP5 allele 4 and ROP18 allele 3 suggested that this strain was avirulent, which was further supported by infection in mice. Encephalitis, immune organ necrosis and focal mononuclear cell infiltration in multiple organs were the main pathology characteristics observed in BALB/C mice infected with the TgServalCHn1 strain. To our knowledge, the present study is the first to report the isolation of T. gondii from a serval, which gives direct evidence for servals serving as an intermediate host of T. gondii. The genotyping results revealed the presence of genotype ToxoDB#20 in central China, enriching the scope of the distribution of T. gondii genotypes in Asia.

Evidence of high exposure to Toxoplasma gondii in free-ranging and captive African carnivores

Toxoplasma gondii is an ubiquitous intracellular protozoan parasite. Mammals and birds are intermediate hosts and felid species are definitive hosts. In most human altered habitats the domestic cat is the predominant definitive host. Current knowledge of T. gondii infection in African ecosystems is limited. This study aimed to assess exposure to T. gondii in wild carnivores in the Serengeti ecosystem in East Africa. Carnivores can be infected by the consumption of tissue cysts when feeding on infected animals and by incidental ingestion of oocysts from environmental contamination. Incidental ingestion should occur regardless of a species’ diet whereas the consumption of cysts should increase the chance of infection in carnivorous species. This predicts higher seropositivity in carnivorous than in insectivorous carnivores and lower seropositivity in juvenile carnivores with a long dependency on milk than in adults. We found high seropositivity in carnivorous species: 100% (15 of 15 samples) in adult African lions, 93% (38 of 41 samples) in adult spotted hyenas and one striped hyena sample was positive, whereas all four samples from the insectivorous bat-eared fox were negative. Juvenile hyenas (11 of 19 sera) had significantly lower seropositivity than adults (38 of 41 sera). Long-term monitoring of spotted hyenas revealed no significant difference in seropositivity between two periods (1988–1992 and 2000 to 2016). Identical results were produced in lion and hyena samples by a commercial multi-species ELISA (at serum dilution 1:10) and an in-house ELISA based on a recombinant T. gondii protein (at serum dilution 1:100), making the latter a useful alternative for small amounts of serum. We suggest that diet, age and lifetime range are factors determining seropositivity in carnivores in the Serengeti ecosystem and suggest that the role of small wild felids in the spread of T. gondii in the African ecosystem warrants investigation.

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Most Serengeti lions and spotted hyenas had anti-T. gondii antibodies.

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Spotted hyenas' seropositivity remains similar in two time periods across 28 years.

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The proportion of seropositive juvenile spotted hyenas was lower than in adults.

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No evidence of infection in 4 wild bat-eared foxes, which are insectivorous canids.

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An in-house ELISA permits the use of small amounts of serum.

Antibody Detection, Isolation, Genotyping, and Virulence of Toxoplasma gondii in Captive Felids from China

The felids are the only definitive hosts of Toxoplasma gondii, which could excrete oocysts into the environment and provide an infection source for toxoplasmosis in various warm-blooded animal species, particularly the captive felids that live close to human communities. The infection rate of the captive felids is a perfect standard in detecting the presence of Toxoplasma gondii oocysts in the environment. In this study, sera or tissue samples from zoo (1 young tiger, 2 adult tigers, 6 young lions), farm (10 masked palm civets), and pet hospital (28 cats) from Henan Province (China) were collected. The sera (n = 47) were tested for immunoglobulin G (IgG) antibodies against T. gondii by using modified agglutination test (MAT), whereas the hearts tissue (n = 40) were bioassayed in mice to isolate T. gondii strains. The genotype was distinguished by using PCR-RFLP of 10 loci (SAG1, SAG2, SAG3, GRA6, BTUB, L358, c22-8, PK1, c29-2, and Apico). The detection rate for the T. gondii antibody in captive felids was 21.3% (10/47). One viable T. gondii strain (TgCatCHn4) was obtained from a cat heart tissue, and its genotype was ToxoDB#9. The oocysts of ToxoDB#9 were collected from a T. gondii-free cat. The virulence of TgCatCHn4 was low and no cysts were detected in the brain of mice at 60 days post-inoculation. The finding of the present study suggested a widespread exposure of T. gondii for felids in Henan Province of central China, particularly those from the zoological gardens and homes. ToxoDB#9 was the predominant strain in China. Preventive measures against T. gondii oocyst contamination of various components of the environment should thus be implemented, including providing pre-frozen meat, well-cooked cat food, cleaned fruits and vegetables, monitoring birds and rodents, inactive T. gondii oocysts in felids feces, and proper hygiene.

Toxoplasmosis in rodents: ecological survey and first evidences in Thailand

Domestic and wild rodents known as the most abundant and diversified order of mammals have a key role in the ecological food chain and also in the transmission of parasites and pathogens to other animals. While foraging on the ground, they can get infected by Toxoplasma gondii, a protozoan parasite, which is the causative agent of toxoplasmosis. Therefore, they serve as intermediate hosts of T. gondii and can transmit it to their predators. To assess their role in the maintenance of T. gondii lifecycle in Thailand, we sampled rodents in a range of biotopes representative of the high biodiversity and conducted a serological survey with latex agglutination test to detect anti-T. gondii antibodies. Overall, 21 of 461 (4.6%) rodents had diagnostically significant antibody titers (cutoff, 1:64). Every species with at least 37 individuals captured tested positive, confirming the wide range of potential mammalian hosts of toxoplasmosis. None of the ecological traits (sex, maturity, morphology, season, or habitat) was found significant to predict the susceptibility to T. gondii both univariately and in a multivariate analysis. However, high prevalences were reported in either forested or anthropized areas. This survey constitutes the first confirmed serological investigation of T. gondii in rodents in Thailand. The rarity of both domestic and wild felids in Thailand emphasizes the importance of rodents in maintaining T. gondii, and questions the involvement of other carnivores in the life cycle.

Waterborne toxoplasmosis--recent developments

Humans become infected with Toxoplasma gondii mainly by ingesting uncooked meat containing viable tissue cysts or by ingesting food or water contaminated with oocysts from the feces of infected cats. Circumstantial evidence suggests that oocyst-induced infections in humans are clinically more severe than tissue cyst-acquired infections. Until recently, waterborne transmission of T. gondii was considered uncommon, but a large human outbreak linked to contamination of a municipal water reservoir in Canada by wild felids and the widespread infection of marine mammals in the USA provided reasons to question this view. The present paper examines the possible importance of T. gondii transmission by water.

Intestinal parasitism in the animals of the zoological garden "Peña Escrita" (Almuñecar, Spain)

Gastrointestinal parasites cause serious diarrhoea in captive animals. Therefore, we have undertaken this study to establish programmes to prevent, control, and treat intestinal parasitism in the animals of the zoological garden "Peña Escrita" of Almuñecar (Granada). An annual survey was conduced to estimate the occurrence of gastrointestinal parasites and the seasonality of this parasitism. Between June 2006 and May 2007, 432 samples were collected from primates, carnivores, perissoodactyla, artiodactyla, rodentia, diprotodontia, galliformes, anseriformes and struthioniformes. One or more intestinal parasites were identified in 72.5% of the animals. The most frequent pathogenic endoparasites were Eimeria spp. (17.3%), Trichuris spp. (5.1%), Strongyloides spp. (4.5%), Cyclospora spp. (4.5%), Cryptosporidium spp. (3.2%) and Isospora spp. (2.6%). Iodamoeba butschlii, Parascaris equorum and Trichuris spp. did not vary with season and Cryptosporidium spp., Dicrocoelium dendriticum, Metastrongylus spp. and Cylicospirura spp. appeared exclusively in Artiodactyla. Multiple parasitic infections were common, 70% of animals presented with at least two parasites (maximum=6). The most frequent cases of multiple parasitism were Eimeria spp. plus Blastocystis spp. and Eimeria spp. plus Nematodirus spp., in the last case the animals presented explosive diarrhoea. In accord with our results, after each sampling, some of the affected animals were treated and the corresponding programmes of prevention and control were designed.