Seroprevalence of Toxoplasma gondii Among Primary School Children in Shandong Province,China

Although Toxoplasma gondii infection in primary school children has been investigated in many countries, limited surveys have been available in primary school children in China. In the present study, we report the seroprevalence of T. gondii infection in primary school children in Shandong province, China. Sera from 6,000 primary school children were evaluated for T. gondii antibodies with ELISA. The overall seroprevalence of T. gondii infection was 16.0% (961/6,000), of which 14.5% (870/6,000) were positive for anti-T. gondii IgG antibodies, 3.4% (206/6,000) positive for IgM, and 1.9% (115/6,000) were positive for both IgG and IgM. The results of the present investigation indicated a high seroprevalence of T. gondii infection in primary school children in Shandong province, China. Therefore, effective measures should be taken to prevent and control T. gondii infection in primary school children in this province. To the best of our knowledge, this is the first report of T. gondii seroprevalence in primary school children in Shandong province, China.     

Serologic Survey of Toxoplasmosis in Seoul and Jeju-do, and a Brief Review of Its Seroprevalence in Korea

Knowledge of the prevalence of human Toxoplasma gondii infection is required in the Republic of Korea. In this study, we surveyed the seroprevalence of T. gondii infection and analyzed the risk factors associated with seropositivity among residents in 2 administrative districts; Seoul and the island of Jeju-do, which have contrasting epidemiologic characteristics. Sera and blood collected from 2,150 residents (1,114 in Seoul and 1,036 in Jeju-do) were checked for IgG antibody titers using ELISA and for the T. gondii B1 gene using PCR. In addition, participants completed a questionnaire that solicited information on gender, age, occupation, eating habits, history of contact with animals, and travel abroad. The T. gondii B1 gene was not detected in all residents examined. However, ELISA showed 8.0% (89 of 1,114 sera) positive for IgG antibodies against T. gondii in Seoul and 11.3% (117 of 1,036 sera) in Jeju-do. In both districts, the positive rates were higher in males than in females, and those 40-79 years of age showed higher rates than other ages. In Seoul, residents older than 70 years of age showed the highest positive rate, 14.9%, whereas in Jeju-do the highest prevalence, 15.6%, was in those in their sixties. The higher seropositive rate in Jeju-do than in Seoul may be related to eating habits and occupations. The present results and a review of related literature are indicative of an increased seroprevalence of T. gondii in Korea in recent years.     

Seroepidemiological study of Toxoplama gondii in small ruminants (sheep and goat) in different provinces of Mongolia

Toxoplasmosis is caused by the protozoan parasite Toxoplasma gondii. Consumption of raw or undercooked meat is the main risk factor for acquiring T. gondii infection in humans. Meat and meat products derived from goats and sheep are mainly consumed in Mongolia; however, there is limited epidemiological information on T. gondii infection in small ruminants in this country. The main objective of the present study was to investigate the seroprevalence of T. gondii in sheep and goats in Mongolia. The seroprevalence of T. gondii IgG antibodies was determined by an indirect enzyme-linked immunosorbent assay based on the recombinant antigens of dense granule protein 7 of T. gondii. A total of 1078 goat and 882 sheep blood samples were collected from 17 of 21 provinces and the capital city of Mongolia. Overall, the seroprevalence of T. gondii among the goat and sheep samples was 32% and 34.8%, respectively. The seroprevalence among goat samples was significantly higher in western (42.7%) and eastern (45.6%) regions compared with other regions (24%). Additionally, the seroprevalence among sheep was significantly higher in eastern regions (55.4%) compared with other regions (26%–33%). Age, but not sex, was considered a risk factor for T. gondii seropositivity in goats, whereas no statistically significant differences were observed in sheep for age or sex. In conclusion, the present study demonstrates the high seroprevalence of T. gondii in small ruminants in Mongolia. Our results highlight that country-wide control measures are required to minimize infections in livestock.     

Seroprevalence and B1 gene genotyping of Toxoplasma gondii in farmed European mink in the Republic of Tatarstan,Russia

Toxoplasma gondii is a protozoan parasite that infects almost all species of mammals and birds, including fur-bearing animals. However, the prevalence of T. gondii among Russian fur-bearing animals is unknown. In this study, the seroprevalence of T. gondii in European mink in Russia was investigated. In total, 100, 119 and 61 serum samples were collected from a fur farm, located in the Republic of Tatarstan, Russia, in autumn 2016, 2017 and 2018, respectively. The seroprevalence of T. gondii in 2016, 2017 and 2018 was 32% (23.2%–42.2%, 95% confidence interval [CI]), 31.1% (23.1%–40.3%, 95% CI) and 41.0% (28.8%–54.3%, 95% CI), respectively. In total, 50 brain samples from 100 animals whose blood was sampled in 2016 were analyzed by PCR to detect T. gondii DNA. T. gondii DNA was detected in 14% (7/50) of the mink brain samples. To examine single nucleotide polymorphisms (SNPs) in the partial B1 gene, we sequenced an 836-bp fragment, which contains a few SNPs, from the detected T. gondii DNA. The sequences of the fragments were identical to those of two of the major lineages, Type II and Type III, but differed from that of the Type I lineage.     

Seroprevalence of Toxoplasma gondii in pigs in Southwestern China

The seroprevalence of toxoplasmosis in pigs was investigated in Yunnan province, Southwestern China between March 2008 and January 2009. A total of 831 serum samples were collected from 9 counties and assayed for Toxoplasma gondii antibodies by indirect haemagglutination (IHA) test. Antibodies to T. gondii were found in 16.97% (141/831) with slaughter pigs having the highest rate (22.28%), followed by breeding sows (16.59%). The results of the present survey indicated that infection with T. gondii in pigs is widely spread in China, including the Yunnan province, and is of public health concern.     

Prevalence of anti-Toxoplasma gondii antibody in domestic horses in Japan

The present study is the first report that investigated the seroprevalence of Toxoplasma gondii infection in domestic horses in various prefectures of Japan and analyzed risk factors for seropositivity. We performed a latex agglutination test for riding/racing horses from 11 prefectures in Japan (783 samples) and 4 groups of Japanese native horses (254 samples). The total seroprevalence of anti-T. gondii antibody in horses examined in this study was 4.24% (44/1037). As for riding/racing horses, we did not find a statistically different T. gondii seroprevalence between sampling prefectures. In contrast, seroprevalence of T. gondii in older horses (> 21 years) was significantly higher than that in younger horses (< 5 years and 11–15 years). There was no significant difference in T. gondii seroprevalence between riding/racing horses and Japanese native horses. Logistical regression analysis revealed that age, but not sex and usage, is a significant risk factor of T. gondii infection for domestic horses in Japan. These findings suggest that domesticated horses in Japan can be horizontally infected with T. gondii by ingestion of food or water contaminated with oocysts.     

Seroprevalence of Toxoplasma gondii Infection in Police Dogs in Shenyang,Northeastern China

In recent years, worldwide surveys of Toxoplasma gondii infection in dogs have been reported. However, only limited surveys of T. gondii infection in police dogs have been available, including China. In the present study, we report the seroprevalence of T. gondii in police dogs in Shenyang, northeastern China. Sera from 291 police dogs were examined for T. gondii antibodies with the modified agglutination test (MAT), and 30.9% animals were tested seropositive. The results of the present study indicated a relatively high prevalence of T. gondii infection in police dogs in Shenyang, China.     

Seroprevalence of Toxoplasma gondii Infection among HIV/AIDS Patients in Eastern China

Toxoplasmosis, a neglected tropical disease caused by the protozoan parasite Toxoplasma gondii, occurs throughout the world. Human T. gondii infection is asymptomatic in 80% of the population; however, the infection is life-threatening and causes substantial neurologic damage in immunocompromised patients such as HIV-infected persons. The major purpose of this study was to investigate the seroprevalence of T. gondii infection in subjects infected with HIV/AIDS in eastern China. Our findings showed 9.7% prevalence of anti-T. gondii IgG antibody in HIV/AIDS patients, which was higher than in intravenous drug users (2.2%) and healthy controls (4.7%), while no significant difference was observed in the seroprevalence of anti-Toxoplasma IgM antibody among all participants (P>0.05). Among all HIV/AIDS patients, 15 men (7.7%) and 10 women (15.9%) were positive for anti-T. gondii IgG antibody; however, no significant difference was detected in the seroprevalence of anti-Toxoplasma IgG antibody between males and females. The frequency of anti-Toxoplasma IgG antibody was 8.0%, 13.2%, 5.5%, and 0% in patients with normal immune function (CD4⁺ T-lymphocyte count ≥500 cells/ml), immunocompromised patients (cell count ≥200 and <500 cells/ml), severely immunocompromised patients (cell count ≥50 and <200 cells/ml), and advanced AIDS patients, respectively (cell count <50 cells/ml), while only 3 immunocompromised patients were positive for anti-T. gondii IgM antibody. The results indicate a high seroprevalence of T. gondii infection in HIV/AIDS patients in eastern China, and a preventive therapy for toxoplasmosis may be given to HIV/AIDS patients based on CD4⁺ T lymphocyte count.     

Seroprevalence and risk factors associated with Toxoplasma gondii in domestic pigs from Spain

Serum samples from 2970 (1400 sows, 1570 fattening) pigs, from 100 farms in the 10 main swine production regions in Spain were tested for antibodies against T. gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT 1:25 or higher) were detected in 492 pigs (16.6%, 9.7% in fattening pigs and 24.2% in sows). The herd prevalence was 85.0% (95% CI: 78–92) and within-farm prevalence ranged from 2.9% to 92.8% (median = 17.6%). Statistically significant differences were observed among sampling regions with seroprevalence significantly higher in pigs from Valencia Community (27.3%), Extremadura (23.3%) and Catalonia (21.2%). A generalized estimating equations model indicated that the risk factors associated with T. gondii seroprevalence were: age, sows compared to fattening pigs (OR = 2.9; 95% CI = 1.83–4.53), lack of rodent control (OR = 1.9; 95% CI = 1.04–3.60) and presence of cats (OR = 1.6; 95% CI = 1.12–2.34). The seroprevalence observed in the present study indicates a widespread, although variable, exposure to T. gondii among domestic pigs in Spain, which might have important implications for public health. Management measures including control of rodents and cats on the farms could help to reduce the observed prevalence levels in Spain.     

Seroprevalence of Toxoplasma gondii and Trichinella spiralis infections in wild boars (Sus scrofa) in Korea

Toxoplasma gondii and Trichinella spiralis are important zoonotic pathogens with worldwide distributions. In Korea, several outbreaks of human toxoplasmosis and trichinellosis due to the consumption of infected wild animals have been reported. The purpose of this study was to determine the seroprevalence of T. gondii and T. spiralis infections in wild boars killed in Korea from December 2009 to October 2011. A total of 521 wild boars hunted in eight provinces were examined for antibodies to T. gondii and T. spiralis by using commercial ELISA kits. Overall, 25.1% of serum samples from individual boars were seropositive for T. gondii and 1.7% were seropositive for T. spiralis. Seropositive for T. gondii was found in the boars in all the eight provinces investigated and for T. spiralis in four provinces. This is the first report on the seroprevalence of T. gondii and T. spiralis infections in wild boars in Korea. The consumption of undercooked wild boar meat may expose humans to a high risk of infection.     

Seroprevalence of Toxoplasma gondii and Neospora caninum in slaughtered pigs in the Czech Republic

In the Czech Republic, sera from 551 clinically healthy adult slaughtered pigs (females, 6-8 months old) were collected during the first half of June in 2010. Sera were tested for Toxoplasma gondii-specific IgG antibodies by an enzyme-linked immunosorbent assay; samples with more than 50% S/P were considered as positive. The same samples were also analysed for Neospora caninum antibodies using a commercial competitive-inhibition enzyme-linked immunosorbent assay; samples with more than 30% inhibition were considered as positive. Antibodies against T. gondii were found in 198 pigs (36%) in all districts with prevalences ranging from 18% to 75%. Antibodies against N. caninum were found in 16 pigs (3%); positive animals were found in 4 districts with prevalences ranging from 1% to 20%. Indication of mixed infections (concurrent presence of both N. caninum and T. gondii antibodies) was found in 8 (1·5%) pigs. The results of our study indicate that pigs in the Czech Republic have a relatively high seroprevalence for T. gondii, while they have only a low seroprevalence for N. caninum. Therefore, natural infection with T. gondii seems to be very common in Czech pigs. It is the first evidence of N. caninum antibodies in pigs in the Czech Republic. These results complete data about N. caninum infection in pigs in Europe.     

Prevalence and isolation of Toxoplasma gondii in goats slaughtered for human consumption in the semi-arid of northeastern Brazil

The aim of this study was to determine the seroprevalence of anti-Toxoplasma gondii antibodies and factors associated with infection in goats, and to isolate protozoan strains in tissue samples from seropositive goats that were destined for human consumption in the state of Paraíba, northeastern Brazil. Serum samples from 229 slaughtered goats were tested using the indirect fluorescence antibody test (IFAT), with a cutoff point of 1:64. Epidemiological questionnaires were applied to the producers, to acquire information about the sanitary management used in their herds. Tissue samples from the animals were collected during slaughter, in order to perform bioassays in mice. The seroprevalence found was 21.39% (49/229), with antibody titers ranging from 1:64 to 1:32,768. The municipalities of origin, Patos (OR: 3.047; CI: 1.384–6.706) and Sousa (OR: 3.355; CI: 1.536–7.327), were considered to be factors associated with infection by T. gondii. Thirty-eight bioassays were performed in mice, using tissues from seropositive goats, with an isolation rate of 50% (19/38). There was no correlation between isolation rate and antibody titers. Only one mouse died, at 30 days post-infection, which demonstrated that the strains isolated had low virulence towards mice. It was concluded that there is high seroprevalence in goats in northeastern Brazil, as well as a high percentage of viable tissue cysts in slaughtered animals destined for human consumption. These results demonstrate that there is an imminent one health problem relating to toxoplasmosis, especially in the most populous municipalities in the study (Patos and Sousa), which were identified as factors associated with T. gondii infection in goats.     

Negative trend in seroprevalence of anti-toxoplasma gondii IgG antibodies among the general population of the province of Vojvodina,Serbia, 2008–2021

This study aimed to estimate dynamic changes in seroprevalence of Toxoplasma gondii within the general population living in the northern part of the Republic of Serbia (Province of Vojvodina) during a 14-year period. The differences in prevalence of anti-toxoplasma antibodies were analyzed in correlation with age, gender, residential area (rural/urban) and meteorological factors. In this cohort retrospective study, 24,440 subjects between 1 and 88 years old were enrolled. To determine the presence of T. gondii-specific IgM and IgG antibodies in serum samples, commercially available ELISA kits were used (Euroimmun, Luebeck, Germany). During the study period, the overall T. gondii seroprevalence was 23.5%. The seroprevalence continuously decreased over time from 31.7% in 2008 to 20.4% in 2021 (0.81% per year, p < 0.001). Approximately 2% of patients had a serologic profile positive for both anti-Toxoplasma IgG and IgM antibodies. The seroprevalence was higher (28.87%) among men compared to women (24.28%), while urban residents (24.94%) had lower seroprevalence than the rural population (28.17%). A statistically significant negative correlation (r = −0.559) was found between serologic profile of patients positive for both T. gondii IgG and IgM antibodies and the annual mean air temperature. No significant association was observed between seropositivity to T. gondii infection and examined meteorological factors. These data could be useful to national and regional health authorities to create an optimal health policy to reduce rate of T. gondii infections.     

Seroepidemiology of Toxoplasma gondii Infection among Healthy Blood Donors in Taiwan

Toxoplasma gondii is an opportunistic, zoonotic pathogen with a worldwide distribution. There are large variations in the seroprevalence of T. gondii infection in different regions of the world. Although toxoplasmosis became a notifiable communicable disease in Taiwan in 2007, little is known about its epidemiology among the general population. This cross-sectional study aimed to survey the seroprevalence of T. gondii infection and its risk factors among healthy blood donors in Taiwan. Through collaborating with the Taiwan Blood Services Foundation, a total of 1,783 healthy blood donors from all six-branch blood service centers participated in this study. The blood samples were tested for the presence of T. gondii antibodies and DNA using enzyme immunoassays and real-time PCR, respectively. Structured questionnaires were used to gather information on risk factors for T. gondii infection. Of the 1,783 participants, 166 (9.3%) tested positive for anti-Toxoplasma IgG, while 5 (0.28%) tested positive for anti-Toxoplasma IgM. The five IgM positive donors had high avidity antibodies suggestive of past infection. No active parasitemia was detected by real-time PCR assays. Multivariate logistic regression showed that undercooked pork meat consumption (adjusted odds ratio [OR] = 2.9; 95% confidence interval [CI]: 1.3–6.5), raw mussels consumption (adjusted OR = 5.3; 95% CI: 1.5–19.1), having a cat in the household (adjusted OR = 2.0; 95% CI: 1.2–3.2), a lower education level (adjusted OR = 1.6; 95% CI: 1.1–2.3), and donation place in eastern Taiwan (adjusted OR = 2.5; 95% CI: 1.6–3.9) were independent risk factors for Toxoplasma seropositivity. These findings provide information on the seroprevalence and epidemiology of T. gondii infection among healthy blood donors in Taiwan.     

Toxoplasma gondii in wild and domestic animals from New Caledonia

Samples (serum or meat juice) collected from 205 animals in New Caledonia in April 2009 were tested for antibodies against Toxoplasma gondii by ELISA using the multi-species ID Screen^® Toxoplasmosis Indirect kit (IDVET, Montpellier). Antibodies to T. gondii were detected in 2% (1/49) of the pigs, in 3.3% (1/30) of the cattle, in 13.8% (4/29) of Rusa deers, in 16% (4/25) of the horses, in 32.8% (21/64) of the dogs, and in 50% (4/8) of cats. Statistically, no significant difference was observed between T. gondii seroprevalence and age or sex. No survey on the prevalence of T. gondii in animals has ever been conducted in New Caledonia and this is the first serological evidence of T. gondii in Rusa deer (Cervus timorensis russa). These results indicate an important circulation of T. gondii exists in the animal populations of New Caledonia. In view of humans being exposed, it is advisable to insist on sanitary education and on respect for good hygienic and food practice.     

High Toxoplasma gondii Seropositivity among Brain Tumor Patients in Korea

Toxoplasma gondii is an intracellular protozoan that can modulate the environment of the infected host. An unfavorable environment modulated by T. gondii in the brain includes tumor microenvironment. Literature has suggested that T. gondii infection is associated with development of brain tumors. However, in Korea, epidemiological data regarding this correlation have been scarce. In this study, in order to investigate the relationship between T. gondii infection and brain tumor development, we investigated the seroprevalence of T. gondii among 93 confirmed brain tumor patients (various histological types, including meningioma and astrocytoma) in Korea using ELISA. The results revealed that T. gondii seropositivity among brain tumor patients (18.3%) was significantly (P<0.05) higher compared with that of healthy controls (8.6%). The seropositivity of brain tumor patients showed a significant age-tendency, i.e., higher in younger age group, compared with age-matched healthy controls (P<0.05). In conclusion, this study supports the close relationship between T. gondii infection and incidence of brain tumors.     

Serological evidence of Toxoplasma gondii and Neospora caninum infection in black-boned sheep and goats in southwest China

Toxoplasma gondii and Neospora caninum are two closely related protozoan parasites which can cause abortion and significant economic losses in sheep and goats. However, it is yet to know whether black-bone sheep and goats are infected with T. gondii and N. caninum in China. In the present investigation, the seroprevalence and risk factors of T. gondii and N. caninum infections in black-boned sheep and goats were investigated in Yunnan Province, subtropical southwest China between July and August of 2017. A total of 481 serum samples were tested for T. gondii antibodies using the Modified Agglutination Test (MAT), and 468 serum samples were examined for N. caninum antibodies by indirect Enzyme-Linked Immunosorbent Assay (iELISA). The overall seroprevalence of T. gondii in black-boned sheep and goats was 36.80% (177/481, 95% CI 32.49–41.11), and 40 out of 468 serum samples were N. caninum-seropositive (8.55%, 95% CI 6.02–11.08). There was significant difference in the seroprevalence of T. gondii infection in different regions (χ² = 19.869, df = 2, P<0.01). As for the seroprevalence of N. caninum infection, region (χ² = 8.558, df = 2, P<0.05), age (χ² = 16.631, df = 3, P < 0.01), gender (χ² = 11.219, df = 1, P < 0.01) and species (χ² = 8.673, df = 1, P < 0.01) were the risk factors. In addition, the seroprevalence of coinfection of T. gondii and N. caninum in black-boned sheep and goats was 3.63% (17/468, 95% CI 1.94–5.32). To our knowledge, this is the first report of T. gondii and N. caninum seroprevalence in black-boned sheep and goats in China, which provided base-line data for the execution of control strategies and measures against T. gondii and N. caninum infection in black-boned sheep and goats.     

Toxoplasma gondii seroprevalence in goats,cats and humans in Russia

Toxoplasmosis, a most common zoonosis, is caused by the protozoan parasite Toxoplasma gondii. However, there is little epidemiological information on T. gondii infections in humans and livestock animals in Russia. Therefore, in this study, the seroprevalence of T. gondii in goats in Russia was investigated. A total of 216 goats from 32 farms were investigated and 95 of them were seropositive for T. gondii. The difference in seroprevalence between the examined regions was not statistically significant. We next collected serum samples from 99 cats and 181 humans in Kazan city, the state capital of the Republic of Tatarstan, Russia, and examined their T. gondii seroprevalences. Thirty-nine of the 99 cat samples and 56 of the 181 human samples showed seropositivity. Logistical regression analysis revealed that the cat breeding history of the human subjects, but not their sex or age is a significant risk factor for T. gondii seropositivity. These findings suggest that the natural environment in Russia may be widely polluted with T. gondii oocysts shed by cats, and ingestion of these oocysts provides a major route for human infection with this parasite.     

Seroprevalence of Toxoplasma gondii in the U.S.: Evidence from a representative cross-sectional survey.

The National Health and Nutrition Examination Survey (NHANES) evaluates the epidemiology in the U.S. population of certain infectious diseases, including Toxoplasma gondii (T. gondii), a protozoan parasite. This study aims to evaluate the seroprevalence of T. gondii -IgG antibodies using NHANES data to identify risk factors related to T. gondii. Using NHANES 2009–10, 2011–12, and 2013–14 cycles, univariate analyses and logistic regression models were conducted to determine the relationship between T. gondii seropositivity and various risk factors. Across the three cycles, 13.3% of participants tested positive for T. gondii-IgG seroprevalence, with a significant decrease in seroprevalence from the earlier to later cycles. 53.4% of individuals with positive serology were male. The probability of testing positive for T. gondii -IgG significantly increases between four and five times from the 18–29 age group to 70–79 age group. Seroprevalence also differed by ethnicity, with Latinos of any race having two times higher odds of testing positive for T. gondii compared to other ethnicities. Other sociodemographic factors were associated with lower odds of T. gondii seropositivity, including college education, higher household income, and health insurance. Most clinical conditions were not significantly associated with T. gondii, excluding depression, which was observed in 25% of patients positive for T. gondii-IgG. Further research on the influence of this parasite on infected individuals, including predispositions for risk-taking, is needed to better understand the relationship between Toxoplasma gondii, depression, and other mental illnesses.     

Prevalence of Toxoplasma gondii in Dogs in Zhanjiang,Southern China

Toxoplasmosis, caused by Toxoplasma gondii, is a parasitic zoonosis with worldwide distribution. The present study investigated the prevalence of T. gondii in dogs in Zhanjiang city, southern China, using both serological and molecular detection. A total of 364 serum samples and 432 liver tissue samples were collected from the slaughter house between December 2012 and January 2013 and were examined for T. gondii IgG antibody by ELISA and T. gondii DNA by semi-nested PCR based on B1 gene, respectively. The overall seroprevalence of T. gondii IgG antibody was 51.9%, and T. gondii DNA was detected in 37 of 432 (8.6%) liver tissue samples. These positive DNA samples were analyzed by PCR-RFLP at 3''- and 5''-SAG2. Only 8 samples gave the PCR-RFLP data, and they were all classified as type I, which may suggest that the T. gondii isolates from dogs in Zhanjiang city may represent type I or type I variant. This study revealed the high prevalence of T. gondii infection in dogs in Zhanjiang city, southern China. Integrated measures should be taken to prevent and control toxoplasmosis in dogs in this area for public health concern.