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

Pre-Transplant Seroprevalence, Associated Factors, and Post-Transplant Incidence of Toxoplasma gondii Infection Among Heart Transplant Recipients in Japan

BACKGROUND

Among solid organ transplant (SOT) recipients, heart transplant (HT) recipients are at a higher risk of Toxoplasma gondii infection. As Toxoplasma seroprevalence varies by geographic location, updated local epidemiology is essential to guide preventive and therapeutic strategies. However, the Toxoplasma seroprevalence and incidence of post-transplant toxoplasmosis among SOT recipients in Japan are unknown.

METHODS

We performed a single-center retrospective observational study at an HT center in Tokyo, Japan. All HT recipients aged ≥18 years between 2006 and April 2019 were included. We reviewed patient charts and conducted a questionnaire survey to investigate the risk factors for infection.

RESULTS

Among 105 recipients included in the study, 11 (10.5%) were seropositive before transplant. Ninety-five recipients (90.5%), including all pre-transplant seropositive recipients, answered the questionnaire. The recipients who had lived in Okinawa (odds ratio [OR] 7.5 [95% CI 1.42-39.61]; P = .032) and who reported raw-meat eating habits (OR 4.64 [95% CI 1.04-23.3]; P = .021) were more likely to be seropositive. None of the patients developed symptoms of toxoplasmosis. The post-transplant incidence of other major adverse outcomes was not significantly different according to the pre-transplant serostatus.

CONCLUSIONS

About 10% of HT recipients at an HT center in Tokyo were seropositive for Toxoplasma pre-transplant, and none developed symptomatic toxoplasmosis post-transplant on trimethoprim-sulfamethoxazole. The history of raw meat consumption was associated with seropositivity; therefore, avoiding it might be recommended for HT recipient candidates.

Seroprevalence and Risk Factors for Toxoplasma gondii Infection in Horses

BACKGROUND

Toxoplasma gondii is classified as intracellular protozoa and is one of the major zoonotic parasites. Most warm-blooded intermediate hosts, including humans, are commonly infected by this parasite. The epidemiology of T. gondii infection in Egyptian horses is currently poorly understood.

METHODS

420 blood samples were randomly collected from horses raised in four governorates in Northern Egypt (110 each from Giza and Kafr El Sheikh, and 100 each from Qalyubia and Gharbia) to investigate the existence of antibodies against T. gondii using a commercial ELISA kit, and to ascertain the risk factors for the infection.

RESULTS

the antibodies for T. gondii were found in 16.2% (68/420) of the examined horses, with no significant differences among the four studied governorates. The highest prevalence rate was observed in Giza. The results revealed that sex, breed, age, and contact with domestic ruminants or cats were recognized as potential risk factors. The high prevalence rate was found in mixed breed horses (OR = 2.63, 95% CI: 0.95-7.26), mares (OR = 2.35, 95% CI: 1.31-4.19), and horses aged over 10 years (OR = 2.78, 95% CI: 1.30-3.44). Moreover, the likelihood of seropositivity for T. gondii infection was higher in horses raised in environments with cats (OR = 1.97, 95% CI: 1.13-3.44, p = 0.017) or domestic ruminants (OR = 2.16, 1.21-3.86, p = 0.010). This report confirms that horses in Northern Egypt are exposed to T. gondii and thus raises the possibility that people and other animals could contract the disease.

CONCLUSIONS

routine examination and management of T. gondii infection in horses in these governorates is advised.

Toxoplasma gondii in humans and animals in Japan: An epidemiological overview

Toxoplasmosis is a cosmopolitan protozoan zoonosis caused by Toxoplasma gondii infamous for inducing severe clinical manifestations in humans. Although the disease affects at least one billion people worldwide, it is neglected in many countries including developed ones. In literature, the epidemiological data documenting the actual incidence of the disease in humans and domestic animals from Japan are limited and importantly many earlier papers on T. gondii infections were published in Japanese and a considerable part is not available online. Herein, we review the current summary about the epidemiological situation of T. gondii infection in Japan and the potential associated risk factors in humans and animals as well as the different T. gondii genotypes isolated in Japan. Several T. gondii isolates have been identified among cats (TgCatJpTy1/k-3, TgCatJpGi1/TaJ, TgCatJpObi1 and TgCatJpOk1-4) and goats (TgGoatJpOk1-13). This literature review underscores the need for a nationwide investigation of T. gondii infection in Japanese people and assessment of the socioeconomic impact of the disease burden. Furthermore, epidemiological studies in domestic and wild animals and estimation of degree of contamination of soil or water with T. gondii oocysts are needed, for a better understanding of the scope of this public health concern.

Toxoplasma gondii infections in horses, donkeys, and other equids: The last decade

Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, and genetic diversity of T. gondii in horses, donkeys and other equids in the past decade. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Seroprevalence of Toxoplasma gondii in horses: A global systematic review and meta-analysis

Toxoplasmosis, one of the most common zoonoses worldwide, is caused by Toxoplasma gondii. T. gondii can infect almost all warm-blooded animals, including humans. Horses are an intermediate host of T. gondii, representing a potential risk for humans. To determine the T. gondii seroprevalence in horses worldwide, a global meta-analysis was conducted. A total of 35 publications were obtained by searching the PubMed, ScienceDirect, Chinese Web of knowledge (CNKI) and Wanfang databases. A total of 12,354 horses were assessed, of which 1580 were positive for T. gondii. The pooled overall seroprevalence of horses infected by T. gondii was 11.29%. No significant difference of T. gondii seroprevalence was observed between male and female horses. The seroprevalence of T. gondii in horses from different countries varied. Our findings suggest that toxoplasmosis is prevalent in horses worldwide. Therefore, it is necessary to implement continuous monitoring of the status of T. gondii seroprevalence in horses. Moreover, powerful regulatory measures should be implemented to prevent and control the spread of toxoplasmosis.

Toxoplasma gondii Seroprevalence in Horses from Ukraine: an Investigation Using Two Serological Methods

BACKGROUND

Horses are recognized as important hosts for the zoonotic parasite Toxoplasma gondii, mainly because meat of infected horses can be a source of human T. gondii infections. However, the baseline knowledge on equine T. gondii infections is limited and lacking from many countries. This seroepidemiological study was set in Ukraine, a country where little is known about T. gondii prevalence in any host species.

METHODS

We investigated 78 serum samples from horses, collected from Kyiv and Lviv regions of Ukraine, using a commercial enzyme-linked immunosorbent assay (ELISA) and a commercial modified direct agglutination test (DAT). The ELISA is intended to detect the presence of total antibodies against T. gondii, and the DAT detects specific anti-T. gondii immunoglobulin G antibodies. The cutoff titer for DAT seropositivity was a titer of 40.

RESULTS

Two horses were omitted from statistical analyses due to disagreeing ELISA results. Altogether 16 of the remaining 76 horses were seropositive with the ELISA, yielding an apparent seroprevalence estimate of 21.1% (95% confidence interval 13.0-31.3). Five horses tested positive with both ELISA and DAT, 11 horses tested positive with ELISA only, and one with DAT only. For 64 of the 76 horses, the results of ELISA and DAT agreed; the percent agreement was 84.2 and the Kappa statistic was - 1.5208, indicating poor agreement.

CONCLUSION

Our results add to the knowledge on the global epidemiology of T. gondii and exposure level of horses to the major zoonotic parasite, as well as to the discussion of challenges of applying serology to estimate exposure to T. gondii in horses.

Seroepidemiological study of the exposure to Toxoplasma gondii among horses in Algeria and analysis of risk factors

AIM

The aim of this study was to assess the seroprevalence of the Toxoplasma gondii in horses in different parts of Algeria and to determine risk factors for the infection.

MATERIALS AND METHODS

A total of 736 blood samples were collected from horses of various breeds, gender, coat colors, and ages. All horses came from various farms, racecourses, and equestrian centers. The seroprevalence was investigated by three different methods: Indirect fluorescent antibody test (IFAT) as reference method, enzyme-linked immunosorbent assay (ELISA), and latex agglutination test (LAT).

RESULTS

Out of the 736 sera, 178 (24.18%) were positive for IFAT, 133 (18.07%) for LAT, and 317 (43.07%) for ELISA. It was found that IFAT and LAT were in high agreement (Kappa 0.79), indicating that LAT and IFAT had similar capabilities in the detection of anti-T. gondii antibodies from horse sera. Risk factors analysis based on IFAT results indicated that the habit of the animals was significant risk factors (p≤0.05) for Toxoplasma infection. The seroprevalence was significantly higher in horses living on farms. Moreover, a higher seroprevalence was found in older animals compared to younger ones. Furthermore, the seroprevalence in females was significantly higher than that in males and gelding. Breed, coat color, and water sources are also important factors to influence the seroprevalence of T. gondii.

CONCLUSION

The results indicated that T. gondii is present in horses throughout Algeria and thus represents a risk for both human and animal health. These results underline the need to increase the vigilance and the preventive measures against this disease not only to protect the horses but also to limit the spread of the parasite.

Toxoplasma gondii infection and toxoplasmosis in farm animals: Risk factors and economic impact

The protozoan parasite Toxoplasma gondii is a zoonotic parasite that can be transmitted from animals to humans. Felids, including domestic cats, are definitive hosts that can shed oocysts with their feces. In addition to infections that occur by accidental oral uptake of food or water contaminated with oocysts, it is assumed that a large proportion of affected humans may have become infected by consuming meat or other animal products that contained infective parasitic stages of T. gondii. Since farm animals represent a direct source of infection for humans, but also a possible reservoir for the parasite, it is important to control T. gondii infections in livestock. Moreover, T. gondii may also be pathogenic to livestock where it could be responsible for considerable economic losses in some regions and particular farming systems, e.g. in areas where the small ruminant industry is relevant. This review aims to summarize actual knowledge on the prevalence and effects of infections with T. gondii in the most important livestock species and on the effects of toxoplasmosis on livestock. It also provides an overview on potential risk factors favoring infections of livestock with T. gondii. Knowledge on potential risk factors is prerequisite to implement effective biosecurity measures on farms to prevent T. gondii infections. Risk factors identified by many studies are cat-related, but also those associated with a potential contamination of fodder or water, and with access to a potentially contaminated environment. Published information on the costs T. gondii infections cause in livestock production, is scarce. The most recent peer reviewed reports from Great Britain and Uruguay suggest annual cost of about 5-15 million US $ per country. Since these estimates are outdated, future studies are needed to estimate the present costs due to toxoplasmosis in livestock. Further, the fact that T. gondii infections in livestock may affect human health needs to be considered and the respective costs should also be estimated, but this is beyond the scope of this article.

Molecular Detection and Genetic Characterization of Toxoplasma gondii from Horses in Three Provinces of China

Horse meat and milk are an important source of nutrition for many Chinese. Previous studies have shown a fairly high prevalence of Toxoplasma gondii infection in horses. However, there is no data concerning the molecular characterization of T. gondii in horses in China. The present study tested 231 cervical lymph node samples of horses from northern China (97 from Jilin, 54 from Liaoning, and 80 from Xinjiang) for the presence of the T. gondii B1 gene by seminested PCR. The B1-positive samples were genotyped at nine nuclear loci, that is, SAG1, alternative SAG2, SAG3, BTUB, c22-8, GRA6, c29-2, PK1, and an apicoplast locus, using PCR-restriction fragment length polymorphism technique. A total of 14 (6.06%) out of 231 samples were T. gondii positive. The overall prevalence of T. gondii in the horses was 5.15% (5/97) for Jilin Province, 5.55% (3/54) for Liaoning Province, and 7.50% (6/80) for Xinjiang Uygur Autonomous Region. Of the 14 positive samples, only 2 were successfully genotyped at all loci, 5 were successfully genotyped at 5-8 loci, and all typed samples belong to ToxoDB genotype no. 9. To our knowledge, this is the first molecular characterization of the T. gondii isolates from horses in China.

The use of Toxoplasma gondii tachyzoites produced in HeLa cells adhered to Cytodex 1 microcarriers as antigen in serological assays: an application of microcarrier technology

Toxoplasma gondii can infect nearly all warm-blooded animals, including humans. In the laboratory diagnosis of toxoplasmosis, serological tests have importance in detecting antibody response. Traditionally T. gondii tachyzoites grown in vivo are being used as an antigen source in serological assays. Currently, tachyzoites produced in vitro are being tested as an antigen source in order to decrease animal use. Microcarrier technology allowed us to grow anchorage-dependent host cells on microcarrier suspension in short time and approximately 10 times more than traditional flask technique. The ability of T. gondii tachyzoites to grow in host cells adhered to microcarriers has not been analyzed yet. In this study, we aimed to develop a novel in vitro culture method to produce T. gondii tachyzoites abundantly using HeLa cells adhered to Cytodex 1 microcarriers. Initially, the growth of HeLa cells adhered to Cytodex 1 was analyzed using RPMI 1640, DMEM, and EMEM. Next, HeLa cells with a concentration of 1 × 10⁵ cells/ml and 2 × 10⁵cells/ml were adhered to Cytodex 1 and grown in spinner flasks. Then, T. gondii tachyzoites were inoculated with 1:1 and 2:1 cell:tachyzoite ratios to HeLa cells adhered to microcarriers in spinner flaks. During continuous production in spinner flasks, tachyzoites were harvested at the 2nd, 4th, and 7th day of culture and the quality of antigens produced from these tachyzoites were tested in ELISA and Western Blotting using sera of patients with toxoplasmosis. The optimization studies showed that finest HeLa inoculation value was 2 × 10⁵cells/ml using RPMI 1640, and the cell:tachyzoite ratio to obtain the highest tachyzoite yield (17.1 × 10⁷) was 1:1 at the 4th day of inoculation. According to the results of ELISA comparing HeLa cell and mouse derived antigens, the highest correlation with mouse antigen was achieved at the 4th day of HeLa cell culture with 1:1 HeLa:tachyzoite ratio (P < 0.0001). The sensitivity and specificity ratios of ELISA were 100%. In addition, Western blotting banding patterns of the antigen derived at the 4th day of HeLa cell culture with 1:1 HeLa:tachyzoite ratio was comparable with mouse derived antigen. Overall, this novel methodology can be an alternative source of antigen in diagnostic assays, decrease animal use for antigen production, and contribute to the solution of ethical and economic problems.

Seroprevalence and risk factors of Toxoplasma gondii infection in horses in Jilin Province and Inner Mongolia Autonomous Region, northern China

Toxoplasmosis is caused by the protozoon Toxoplasma gondii that can infect almost all warm-blooded hosts including horses and humans. Horse meat is one of the most important meat products for human consumption. However, data on seroprevalence of T. gondii in horses intended for human consumption in Northern China is scarce. Thus, a total of 614 serum samples were collected from Jilin Province and Inner Mongolia Autonomous Region (IMAR) between 2015 and 2017, and were detected the seroprevalence for T. gondii by indirect hemagglutination assay test. In the prevalence study, the overall seroprevalence of T. gondii in horses was 17.92% (110/614) by IHA test, at the cut- off 1:64. Horses collected from Changchun (13.58%, P = 0.02) has a significantly lower seroprevalence than those from Meihekou City (21.72%) and Tongliao City (22.81%). Moreover, a significant difference of T. gondii seroprevalence was found between horses ages at less than 12 months (22.75%) and ≥12 months or higher (16.42%, P = 0.002). To our knowledge, this is the first report of seroprevalence of T. gondii in horses in Jilin and IMAR, Northern China. Logistic regression suggested that age and geographical location of horses were identified as risk factors. These findings will provide the useful data for controlling and preventing toxoplasmosis in horses and/or other hosts in China.

Seroepidemiology of non-primate hepacivirus (NPHV) in Japanese native horses

Non-primate hepacivirus (NPHV) is recently identified as a closely related homologue of hepatitis C virus. The previous studies showed a high prevalence of NPHV infection among Japanese domestic horses originated from abroad. The historical distribution of NPHV among horses in Japan, therefore, is still unknown. In this study, seroepidemiological study of NPHV was conducted using 335 sera from five breeds of Japanese native horses. These horses are maintained as the pedigree and are reared apart from other horse breeds. The detection of antibodies against NPHV were conducted by western blot analysis using the recombinant protein of the NPHV core protein. The antibodies against NPHV were detected in all five breeds, 83 out of 335 (23.4%) horses. These results suggested that NPHV was circulating among Japanese native horses.

Characterization of the zoonotic potential of Toxoplasma gondii in horses from Rio de Janeiro State

The aim of this study was to perform a survey on the prevalence of anti-Toxoplasma gondii antibodies in horses from Rio de Janeiro State, Brazil. From 2012 to 2013, a total of 624 blood samples were collected from horses from the eight regions comprising Rio de Janeiro State (Baixadas Litorâneas, Serrana, Norte Fluminense, Noroeste Fluminense, Centro-Sul, Metropolitana, Médio Paraíba, and Costa Verde). All sera samples were tested for anti-T. gondii antibodies by performing the modified agglutination test with a cut-off of 1:25. Positive serology for T. gondii was detected in 22.8% (142/624) of the horses studied. Seropositivity was detected in all regions sampled; furthermore, statistical significance was observed when all locations were compared at once. The Médio Paraíba region had the highest number of positive animals 54.76% (23/42) in the Bonferroni correction among Costa Verde, Centro Sul, Metropolitana, and Serrana (p<0.001). Seropositivity was 39.58% (38/96) in Norte Fluminense, which was the second most prevalent region. The results indicated that the T. gondii parasite is widely distributed in horses in Rio de Janeiro State and represents a risk to public and animal health. These findings emphasize the need to increase control and prevention of this disease in horses.

A systematic review and meta-analysis of the seroprevalence of Toxoplasma gondii in cats in mainland China

BACKGROUND

Toxoplasmosis is caused by Toxoplasma gondii which can infect all warm-blooded animals. As the most common feline definitive host, cats play a vital role in the transmission of T. gondii. However, national estimates of the seroprevalence of T. gondii in cats in mainland China are lacking, and therefore a systematic review and meta-analysis were performed to provide insight into national environmental transmission levels and potential transmission to humans.

METHODS

Studies published up until July 1, 2016, on T. gondii seroprevalence in cats within mainland China were searched for in CNKI, WanFang, CBM, PubMed, Embase and through the reference lists of resulting articles. The seroprevalence with its 95% confidence interval (CI) for each individual study was presented, and then point estimates and their 95% confidence intervals (CIs) of pooled seroprevalence were calculated. Subgroup analyses were performed according to potential risk factors.

RESULTS

A total of 38 eligible studies, published between 1995 to 2016, covering fifteen provinces and municipalities, and involving 7,285 cats, were included. The seroprevalence in cats per study ranged from 3.9 to 79.4% with a median of 20.3%. As substantial heterogeneity existed among studies, a random-effects model was used to estimate the pooled seroprevalence. The value of the point estimate seroprevalence was 24.5% (95% CI: 20.1-29.0). Seroprevalence in stray cats was significantly higher than in pet cats (OR = 3.00, 95% CI: 1.60-5.64). The seroprevalence increased significantly with cat age (P = 0.018) with 17.4% (95% CI: 7.6-27.2) in the group of ≤ 1 year old, 19.5% (95% CI: 12.7-26.3) in the group of ≤ 3 year-old and 31.6% (95% CI: 22.9-40.3) in the group of > 3 year-old.

CONCLUSIONS

The seroprevalence of T. gondii in cats in mainland China was moderate and was associated with cat ownership and age. Due to the increasing prevalence of pet cats in China and the intimate relationship between these cats and humans, this might present a significant exposure risk, particularly for China's large susceptible population. Therefore, further research is needed into the links between cat ownership and human T. gondii infection and how to reduce T. gondii exposure in humans via cat contacts and the environmental contamination with T. gondii oocysts by cats.