Toxoplasma gondii and Neospora caninum in Free-Range Chickens in Henan Province of China

Direct evidence of cheetah (Acinonyx jubatus) as intermediate host of Toxoplasma gondii through isolation of viable strains

Toxoplasma gondii causes lifelong infection in most definitive and intermediate hosts. Clinical cases of toxoplasmosis in captive cheetahs have been reported. However, there are few reports of viable T. gondii strains isolated from cheetahs. Here, T. gondii infection was investigated using molecular and serological assays in cheetahs from China. Modified agglutination test (MAT) (cut-off: 1:25) indicated that all six examined cheetahs (n = 6) showed T. gondii antibodies. Toxoplasma gondii DNA was detected in three out of five cheetahs. Two viable T. gondii strains were isolated from the striated muscles of two cheetahs using mice bioassay. They were designated as TgCheetahCHn1 and TgCheetahCHn2. Genetic characterization of DNA derived from tachyzoites was performed using RFLP-PCR of 10 markers. Toxoplasma gondii TgCheetahCHn1 is ToxoDB PCR-RFLP genotype #319, and the alleles of ROP18/ROP5 types were 3/7. TgCheetahCHn2 is ToxoDB genotype #9, and the alleles of ROP18/ROP5 were 3/6. The average survival time of TgCheetahCHn1-infected Swiss mice was 22 ± 1 days (n = 23), and the mice did not have detectable T. gondii-specific antibodies until 117 ± 30 days post-inoculation (n = 8), therefore, TgCheetahCHn1 had intermediate virulence. TgCheetahCHn2 was avirulent for Swiss mice. Few brain tissue cysts (0-50) were observed in the mice inoculated with TgCheetahCHn1 or TgCheetahCHn2. The results provide direct evidence of cheetah as intermediate host of T. gondii.

Seroepidemiology of Toxoplasma gondii infection and parasite DNA in free-range chickens in Aguascalientes, Mexico

The objectives of the study were to estimate the prevalence of anti-Toxoplasma gondii antibodies in free-range chickens in Aguascalientes, Mexico, its association with certain risk factors, and the frequency of parasite DNA in the heart. Eighty-one small rural family farms were included, and blood and heart samples were taken from 150 clinically healthy, adult, free-range chickens. Serum samples were processed by indirect immunofluorescence antibody test considering a dilution of 1:16 as a positive reaction, while the DNA detection was done by PCR. The correlation between the presence of antibodies and the potential risk factors was estimated with logistic regression. The overall seroprevalence in the examined populations was 67%, with a range from 33% to 100% among municipalities, and 78% of the farms having at least one seropositive bird. The PCR test identified the presence of parasite DNA for one case only. Among the variables, the presence of cats and the presence of other animal species on the farm were the ones that had the highest values, while the presence of feral cats and the presence of noxious fauna were also identified as potential risk factors. The results indicate high soil contamination by T. gondii oocysts, which implies the active role of cats living on the farms.

Seroepidemiology of Neosporosis in Various Animals in the Qinghai-Tibetan Plateau

Neosporosis is a worldwide infectious disease caused by intracellular parasite Neospora caninum that is a major pathogen of abortion in cattle and neurological disorders in other hosts. However, limited data are available on animals exposed to N. caninum in the Qinghai-Tibetan Plateau Area (QTPA), and little is known about whether animals in the plateau area play an important role in the epidemiology of N. caninum. Therefore, indirect ELISAs based on a combination of NcSAG1 and NcGRA7 antigens were developed to examine both N. caninum-specific IgG and IgM antibodies in Tibetan sheep, yak, cow, pig, cattle, horse, chicken, camel, and donkey from the QTPA in this study. The results showed that all current species present- IgG and IgM-positive animals, and that the overall seroprevalence of N. caninum were 18.6 (703/3,782) and 48.1% (1,820/3,782) for the IgG and IgM antibodies, respectively. Further analysis found significant differences from different altitudes in IgG in Tibetan sheep and IgM in the yak. Hence, the present serological results indicate that the tested animal populations in the QTPA are suffering from N. caninum infections or have become carriers of N. caninum antibodies. To the best of our knowledge, this is the first report on current N. caninum-infected animals in the QTPA, the first epidemiology of neosporosis in cow and camel in China, and the first record of N. caninum IgM antibodies in all the surveyed animals in China. This study provides the latest valuable data on the epidemiology of neosporosis in China and in plateau areas of the world.

Isolation, genotyping and virulence determination of a Toxoplasma gondii strain from non-human primate from China

Toxoplasma gondii infects almost all warm-blooded animals, including humans and non-human primates. Many cases of T. gondii infection in non-human primates have been reported worldwide. In this study, 15 monkeys were collected from zoos in Henan Province between 2016 and 2019. A modified agglutination test (MAT) (cut-off: 1:8) showed that 46.7% (7/15) of the heart juices had T. gondii IgG antibody transformation. One viable T. gondii strain was successfully isolated from the myocardium of a rhesus monkey by bioassay in mice. This strain was designated as TgMonkeyCHn1. The DNA of T. gondii tachyzoites was obtained using cell cultures, and the genotype of this strain was determined by PCR-RFLP with 10 markers and the virulence genes ROP5 and ROP18. The genotype and ROP18/ROP5 (3/6) of TgMonkeyCHn1 did not match any known genotypes. In addition, the TgMonkeyCHn1 formed low number of tissue cysts and was non-lethal to mice. To our knowledge, this is the first T. gondii strain isolated from Old World monkeys. Rhesus monkey is a new host record for T. gondii.

Prevalence of Toxoplasma gondii infection in chickens in China during 1993-2021: a systematic review and meta-analysis

Toxoplasma gondii is an important intracellular parasitic protozoan with a variety of hosts, including chickens, which poses a potential threat to public health. However, little is known regarding overall T. gondii infection in chickens in China. Herein, the prevalence and risk factors associated with T. gondii infection in chickens in China were investigated using a meta-analysis. Forty studies regarding the prevalence of T. gondii in chickens in China from 1993 to 2021 were identified using five databases (PubMed, Science Direct, CNKI, Wang Fang, and VIP). Quantitative and potential sources were analyzed through subgroup analysis and meta-regression in R v3.5.2. The overall prevalence of T. gondii in chickens in China was 13.4% (95% confidence interval (CI): 10.9-16.0). In the region subgroup, the lowest prevalence was presented in Northwestern China (6.0%, 95% CI: 3.2-9.5; P < 0.001). Seasonally, T. gondii prevalence was the highest in spring (17.9%, 95% CI: 7.7-30.9; P = 0.007). Among detection methods, the prevalence in the ELISA subgroup was the highest (22.8%, 95% CI: 17.1-29.1; P < 0.001). According to the farming mode, the prevalence of T. gondii in free-range chickens (19.5%, 95% CI: 15.4-23.9) was significantly higher than that in chickens raised by intensive farming (7.4%, 95% CI: 5.1-10.2; P < 0.001). We also estimated the relationships between region, sampling year, chicken age, chicken application, gender, sample classification, study quality, and T. gondii prevalence in chickens in China. Our study showed that region, season, and farming model played important roles in T. gondii infection of chickens. Integrated control measures should be undertaken to reduce the losses caused by T. gondii infection to the chicken industry.

Epidemiology of Neospora caninum infection in free-range chickens (Gallus gallus domesticus) in north central Mexico

The objective of the present study was to investigate the epidemiology of natural infection by N. caninum in free-range chickens from Aguascalientes, Mexico, through identifying the presence of antibodies, its association with certain risk factors, and estimate the frequency of parasite DNA detection in the brain. The study included 150 clinically healthy chickens from 81 small family farms distributed throughout the state, from which blood and brain samples were taken. Serum samples were processed by indirect immunofluorescence considering a dilution of 1:50 as a positive reaction, while the DNA detection was done by PCR; the association between the presence of antibodies and the potential risk factors was estimated through logistic regression. The general anti-N. caninum presence of antibodies in the studied population was 46% (69/150, CI 95% 38-54), with titers of 1:50 in 38, 1:100 in 24, and 1:200 in 7, finding positive cases in 49% of the farms and in 91% of the municipalities that integrate the state. The presence of antibodies found in the municipalities was estimated in a range of 20 to 75%. The frequency of DNA detection was 6% (9/150, CI 95% 2-11). The grain supplementation was identified as the unique risk factor for infection (OR = 2.82; 95% CI, 1.18-6.73, p < 0.019).

Seroprevalence and Epidemiology of Toxoplasma gondii in Animals in the Qinghai-Tibetan Plateau Area, China

Toxoplasma gondii belongs to the Apicomplexan protozoa-an obligate intracellular parasite-causing toxoplasmosis that has a worldwide distribution and is very harmful to both human health and the livestock industry. However, the information on toxoplasmosis in the Qinghai-Tibetan Plateau Area (QTPA) and the seroprevalence of T. gondii in the food-borne animals in that area has been limited. Therefore, this study focused to T. gondii and toxoplasmosis to perform an indirect ELISA test based on recombinant TgSAG2 protein to establish a comprehensive record of the seroprevalence of T. gondii infections in a wide range of animals, including Tibetan sheep (Ovis aries), yaks (Bos grunniens), cows, chicken, pigs, and horses, in the QTPA. Overall, the seropositive rates of the specific-T. gondii IgG and IgM antibodies in all investigated animals were 44.1% (1179/2673) and 18.0% (469/2612), respectively. The 14.9% (389/2612) sera were determined to be both IgG and IgM positive samples, 30.2% (789/2673) were single-IgG seropositive, and a total of 80 in 2612 animals (3.0%) were single-IgM seropositive. Moreover, for the animal species, the pig was the most prevalent animal (90.2%, 304/337) for IgG positivity, followed by Tibetan sheep (50.7%, 460/907), chickens (45.8%, 229/500), yaks (21.1%, 140/663), cows (18.5%, 38/205) and horses (13.1%, 8/61), respectively. For the IgM antibody positivity, the pig was also the most prevalent animal (41.8%, 141/337), followed by Tibetan sheep (21.2%, 191/907), cows (15.1%, 31/205), chickens (12.4%, 62/500) and yaks (6.6%, 44/663), respectively. The significant differences in the prevalent distribution of T. gondii were found in the different altitudes. In conclusion, this study found the high seroprevalence for T. gondii infections among these animal species in the QTPA, and provides new data to facilitate further research for development of control measures against T. gondii infections in the surveyed locations.

Neospora caninum in free-range chickens (Gallus gallus domesticus) from southern Brazil

Neospora caninum is an obligate intracellular parasite that can infect many domestic and wild animals, including birds. These animals are important sources for monitoring of environmental contamination, as they could become infected through sporulated oocysts; however, the real role of birds in the biological cycle of N. caninum remains uncertain. This study aimed to determine the prevalence of anti-N. caninum antibodies, evaluate associated factors, detect the parasite by molecular testing of free-range chickens from Brazil, and evaluate different techniques for its serological diagnosis. Blood samples of 366 chickens from 25 farms were collected for serological assays. The indirect fluorescent antibody test (IFAT) and the indirect enzyme-linked immunosorbent assay (ELISA) were used to detect anti-N. caninum antibodies. Chickens that tested seropositive by IFAT had their brain tissues and a pool of organs (heart, lung, and liver) submitted to PCR for molecular detection of the parasite. Out of 366 chickens, 65 (17.8%) and 163 (44.6%) were seropositive by IFAT and ELISA, respectively. Brain tissues (n=60) and the pools of organs (n=65) were negative in the PCR. Our results showed a high prevalence of antibodies in free-range chickens and that IFAT is the more sensitive technique for the detection of anti-N. caninum antibodies.

Cross-sectional survey for toxoplasmosis in free-range chickens (Gallus gallus domesticus) from the Atlantic Forest area in Alagoas state, Northeastern Brazil

Toxoplasmosis is a parasitic disease, which is prevalent across the world and has a strong environmental component in its transmission chain. The present study determined the seroprevalence and factors related to Toxoplasma gondii infection among free-range chickens from an Atlantic Forest area in Northeastern Brazil. A total of 550 free-range chickens were tested for T. gondii antibodies usingthe indirect fluorescent antibody test (IFAT, cut-off point 1:16), and 269 (48.9%; 95% CI = 44.7-53.1%) were positive. Among the 61 properties 57 (93.4%) had at least one seropositive animal. The robust Poisson regression model showed that the variables/categories associated with the seroprevalence of T. gondii were: region of origin of the animals/urban area (prevalence ratio [PR] = 2.346; P<0.001), management system/use of cages (PR = 1.591; P = 0.019), presence of rodents/yes (PR = 1.295; P = 0.035), and the type of food/use of food scraps (PR = 1.603; P = 0.009). The high prevalence found suggest that this scenario demands careful management, mainly regarding the use of scraps of undercooked or raw food, adequate environmental hygiene and frequent rodentcontrol.

Epidemiologic significance of Toxoplasma gondii infections in chickens (Gallus domesticus): the past decade

Toxoplasma gondii infections are common in humans and animals worldwide. Domestic free-range chickens (Gallus domesticus) are excellent sentinels of environmental contamination with T. gondii oocysts because they feed on the ground. Chickens can be easily infected with T. gondii; however, clinical toxoplasmosis is rare in these hosts. Chickens are comparatively inexpensive and thus are good sentinel animals for T. gondii infections on the farms. Here, the authors reviewed prevalence, the persistence of infection, clinical disease, epidemiology and genetic diversity of T. gondii strains isolated from chickens worldwide for the past decade. Data on phenotypic and molecular characteristics of 794 viable T. gondii strains from chickens are discussed, including new data on T. gondii isolates from chickens in Brazil. This paper will be of interest to biologists, epidemiologists, veterinarians and parasitologists.

Low prevalence of viable Toxoplasma gondii in swine from slaughter houses in the central of China

BACKGROUND

Toxoplasma gondii is widely distributed and can infect many species of warm-blooded animals, including swine. This study aimed to evaluate the prevalence of T. gondii in swines from the central of China. A total of 2798 samples, including 305 hearts, 2086 diaphragms, and 407 sera were collected from different swine in Henan Province, China. The modified agglutination test was used to detect antibodies against T. gondii in sera from jugular vein blood and heart blood (cut-off: 1:25), diaphragm juice (cut-off: 1:10). T. gondii DNA was screened from the digestive fluids of all diaphragm tissue samples and seropositive hearts, and attempt to isolate viable T. gondii strain by bioassay in mice.

RESULTS

A total of 9.94% (278/2798) swine tested positive for T. gondii antibodies. Region, but not gender, was associated with T. gondi seropositivity in swine. T. gondii nucleic acid was not found in the tissue digestive fluids (2090 swines). Three groups of mice showed T. gondii antibodies after having been bioassayed with diaphragm samples (n = 81, which came from 2090 swine). No viable T. gondii strain was isolated from muscle of swine.

CONCLUSIONS

This is the first large-scale survey T. gondi infection in swine from the central of China. Overall, the prevalence of viable T. gondii in swine was low. Nevertheless, T. gondii infection is present in swine from the central of China. Consumers may acquire T. gondii infection from ingestion of raw or undercooked pork.

Low prevalence of antibodies against Toxoplasma gondii in dairy cattle from China's central region

Background

Toxoplasma gondii is an intracellular protozoan that can infect humans and other animals, including cattle. Cattle are one of the world’s main sources of meat, and people who consume raw or undercooked meat and milk of cattle infected with T. gondii can become infected. In this study, a total of 5292 dairy cattle serum samples, collected from 17 cities (Henan Province, China) from January 2015 to September 2017, were screened for antibodies against T. gondii.

Results

Antibodies to T. gondii were found in 1.93% (102/5292) (95% CI, 1.56–2.30) of dairy cattle using a modified agglutination test (cut-off 1:100). The results showed that geographic location and season may be risk factors for T. gondii infection of cattle (P < 0.05), and the seroprevalence of T. gondii in cattle along the Yellow River is higher than other areas.

Conclusions

This is the first large-scale investigation on the seroprevalence of T. gondii infection in cattle from Central China. This survey shows that the T. gondii infection rate of dairy cattle is low; however, these findings provide additional information on the epidemiology of Chinese T. gondii. The possibility of dairy cattle exposure to T. gondii in Central China can not be ignored, and the consumption of raw or undercooked beef or milk may pose a risk to human health.

Prevalence, Risk Factors, and Genotypes of Toxoplasma gondii in Food Animals and Humans (2000-2017) From China

Toxoplasma gondii as a food-borne pathogen, the infection of it in food animals has relation with human toxoplasmosis, but the trends and epidemiological features of T. gondii infections in food animals are rarely studied in China. The aimed of this study was to assess the epidemiology and risks of T. gondii in sheep, goats, swines, chickens, yaks, cattle and humans from 2000 to 2017 and to explore prevention and control strategies. The overall seroprevalence of T. gondii infections in food animals is 23.7% (39,194/165,417, 95%CI, 23.49-23.90%), which is significantly higher than that in humans (8.2%, 95%CI, 8.06-8.39%, 8,502/103,383) (P < 0.0001). Compared the prevalence of T. gondii infections in animals and humans sampled from 2000 to 2010, it was significantly increased in the period 2011 to 2017 (P < 0.0001). Compared the food animals from non-Yangtze River, animals from regions of the Yangtze River have high seroprevalence rates for T. gondii (P < 0.0001). Furthermore, samples from the western to eastern regions of the Yellow River showed an increase in seroprevalence for T. gondii (P < 0.0001). It was speculated that T. gondii oocysts may be transmitted by water and annual precipitation possible help the oocyst spread and retain accessible for potential hosts. Effective prevention and control strategies are including water filtration or water boiling, inactivating oocysts from feline's feces, monitoring birds and rodents. Chinese 1 (ToxoDB#9) is the predominant genotype in food animals from China.

Dembo polymerase chain reaction technique for detection of bovine abortion, diarrhea, and respiratory disease complex infectious agents in potential vectors and reservoirs

Bovine abortion, diarrhea, and respiratory disease complexes, caused by infectious agents, result in high and significant economic losses for the cattle industry. These pathogens are likely transmitted by various vectors and reservoirs including insects, birds, and rodents. However, experimental data supporting this possibility are scarce. We collected 117 samples and screened them for 44 bovine abortive, diarrheal, and respiratory disease complex pathogens by using Dembo polymerase chain reaction (PCR), which is based on TaqMan real-time PCR. Fifty-seven samples were positive for at least one pathogen, including bovine viral diarrhea virus, bovine enterovirus, Salmonella enterica ser. Dublin, Salmonella enterica ser. Typhimurium, and Neospora caninum; some samples were positive for multiple pathogens. Bovine viral diarrhea virus and bovine enterovirus were the most frequently detected pathogens, especially in flies, suggesting an important role of flies in the transmission of these viruses. Additionally, we detected the N. caninum genome from a cockroach sample for the first time. Our data suggest that insects (particularly flies), birds, and rodents are potential vectors and reservoirs of abortion, diarrhea, and respiratory infectious agents, and that they may transmit more than one pathogen at the same time.

Toxoplasma gondii and Neospora caninum in farm-reared ostriches (Struthio camelus) in China

Background

The parasites Toxoplasma gondii (T. gondii) and Neospora caninum (N. caninum) are globally distributed; they infect warm-blooded animals, including many avian species. The aim of this study was to evaluate the presence of these parasites in ostriches from central China. In total, 402 ostrich (Struthio camelus) samples (293 hearts, 77 brains, and 32 serum) from slaughterhouses of the Henan Province and Hebei Province were collected. The heart juice (n = 283) and serum samples (n = 32) were tested for antibodies to T. gondii using the modified agglutination test (MAT). Hematoxylin and eosin (H&E) staining, immunohistochemical (IHC) staining, and the polymerase chain reaction were used to examine the cysts and DNA of T. gondii and N. caninum parasites, respectively.

Results

Antibodies to T. gondii were detected in 6.4% (20/315) (cut-off, 25). No cysts or DNA of T. gondii or N. caninum were observed in any of the 293 hearts and 77 brains.

Conclusion

The results showed a low prevalence of T. gondii antibody in ostriches, compared to that in the other animals. N. caninum occurs at low to negligible frequencies in ostriches from China. This is the first report on screening ostriches in China for T. gondii antibodies.

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.

Seroprevalence, Isolation, Genotyping, and Pathogenicity of Toxoplasma gondii Strains from Sheep in China

Toxoplasma gondii is an important cause of reproductive failure in small ruminants that also poses a risk to consumers who consume undercooked meat. However, little is known about sheep toxoplasmosis in China for the world. Therefore, this study was conducted to assess the prevalence of T. gondii infection in sheep from China, to isolate T. gondii via bioassay in mice and to evaluate the virulence of the isolated T. gondii based on vero cell invasion and mice. A total of 840 samples (304 unfrozen hearts and 536 sera) from sheep in China were collected from 2014 to 2016. Heart samples (n = 36) of T. gondii seropositive sheep (MAT, ≥25) were bioassayed in mice individually. DNA derived from cell cultured tachyzoites of the isolated T. gondii was characterized by PCR-RFLP of 10 loci (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). The virulence of the T. gondii was evaluated based on the mortality and encystation in mice, as well as their growth characteristics in cell culture. Antibodies to T. gondii were found in 174 of 840 (20.71%, 304 hearts juice and 536 sera) sheep by the modified agglutination test (cut-off 1:25). Viable T. gondii was isolated from the hearts of two of 36 seropositive sheep hearts. Both genotypes of the sheep heart isolates were ToxoDB#9. The virulence of the two ToxoDB#9 isolations varied significantly. To the best of our knowledge, this is the first report of isolation of ToxoDB#9 strain of T. gondii from sheep in China.

Seroprevalence of Toxoplasma gondii Infection in Wild Boars, Wild Rabbits, and Wild Chickens in Hubei Province, China

Toxoplasma gondii causes serious infection worldwide in humans and animals. In this study, the seroepidemiology of toxoplasmosis was investigated in wild boars (Sus scrofa) (n=377), wild rabbits (cape hare, Lapus capensis) (n=331), and wild chickens (red junglefwol, Gallus gallus) (n=571) in 4 forested and country sided area of Hubei province of China. For this, blood samples were collected and tested by indirect hemagglutination test (IHA). The seroprevalence was found to be 7.2%, 5.1%, and 12.6% in wild boars, rabbits, and chickens, respectively, with significant differences among these species. The prevalence of T. gondii infection in male and female wild boars was found to be 7.9% and 6.5% (P<0.01), in male and female rabbits was 5.6% and 4.9% (P<0.01), and in male and female chickens was 17.1% and 7.7% (P<0.01), respectively, with significant differences between 2 genders of chickens (P<0.01). The findings of this study may help in planning of the prevention measures against T. gondii infection in wild animals in this area.

Seroprevalence of Toxoplasma gondii infection and risk factors in domestic sheep in Henan province, central China

Sheep are highly susceptible to infections with Toxoplasma gondii and play a major role in the transmission of toxoplasmosis to humans. In the present study, 779 serum samples from sheep were collected from Henan province, central China from March 2015 to May 2016, and antibodies to T. gondii were detected by modified agglutination test (MAT). The overall seroprevalence of T. gondii in sheep was 12.71% (99/779). The risk factors significantly associated with T. gondii seroprevalence were the geographical origin, age, presence of cats, and the rearing system. This is the first report of T. gondii infection in sheep in Henan province, central China, and of an association of seropositivity to T. gondii with risk factors.