Toxoplasma infection in sheep from south of Iran monitored by serological and molecular methods; risk assessment to meat consumers

Molecular evidence of Toxoplasma gondii from the tissue and blood of naturally infected sheep

Toxoplasmosis is a cosmopolitan zoonotic infection that has significant effects on public health and causes economic losses in the livestock industry. The current study was designed to detect the Toxoplasma parasite in sheep blood samples and tissue samples of slaughtered sheep at the Sulaimani abattoir using molecular technique. A total of 300 peripheral sheep blood samples were randomly collected from 20 small ruminant flocks at 4 locations in the Sulaymaniyah province, northern Iraq. Also, 150 meat samples from thigh muscle, heart, and diaphragm were collected from slaughtered sheep. All collected blood samples were subjected to polymerase chain reaction (PCR) amplification to confirm Toxoplasma infection; in addition, meat samples were also analyzed for Toxoplasma by PCR following the digestion process. Of the 300 amplified blood samples, 94 were considered positive for Toxoplasma gondii, with a prevalence rate of 31.3%. The overall prevalence of Toxoplasma among meat samples was 34%. The diaphragm reported a higher infection rate (46%) than the heart (32%), while the femoral muscle reported an infection rate of 24%. Aged animals (older than 24 months) presented a higher infection rate (32.8%) than younger animals (28.9%). Contact with or consumption of uncooked meat from infected sheep increases the chance of parasite transmission to humans.

Seroprevalence of Toxoplasma gondii infection in sheep and goats from different geographical regions of the world: Systematic review and meta-analysis

The Toxoplasma gondii is an obligate intracellular protozoan parasite which significantly impact small ruminant productivity, international animal trade and transboundary movement of animal across the globe. The seroprevalence of T. gondii infection (toxoplasmosis) in sheep and goats is widely studied in many parts of the world and there is a lack of comprehensive information on prevalence estimates considering the global and regional perspectives. The aim of the study was to use systematic review and meta-analysis methods to estimate the global and regional pooled seroprevalence of T. gondii infection in sheep and goats, as well as factors that influence prevalence estimations. Relevant articles reporting the seroprevalence of toxoplasmosis in sheep and/goats were searched in five electronic databases, including PubMed, Web of Science, Scopus, Embase and ProQuest. After the publications were checked to verify they fit the inclusion criteria, a total of 225 articles were included in the systematic review and meta-analysis, reflecting data from 70 countries/regions. The pooled prevalence was estimated using a random effect meta-analysis model. Overall, the seroprevalence of T. gondii infection was 33.86% (95% CI: 30.47-37.25%) in sheep and 31.78% (95% CI: 28.99-34.58%) in goats, with significant variation in prevalence estimates across geographical locations (p < .001). Substantial heterogeneity (I²  > 75%) was observed in most pooled seroprevalence estimates. The T. gondii infection in global sheep and goat population showed uptrend over the period. This information would be useful for epidemiologist, health authorities and farmers in order to plan future T. gondii survey and infection management strategies both locally and internationally.

Molecular identification and genotyping of Toxoplasma gondii isolated from sheep and cattle in northern Iran

Toxoplasmosis, a foodborne disease, in human occurs commonly after the ingestion of tissue cysts via the raw and/or undercooked meat of different infected intermediate hosts such as sheep and cattle. The current study aimed to detect the genetic structure of Toxoplasma gondii isolated from various organs of sheep and cattle in the north of Iran. Conventional PCR was carried out by B1 and REP-529 genes of T. gondii. Nested and RFLP-PCR were performed for all positive samples using SAG2 and GRA6 genetic markers. Amplicons from second round of nested-PCR were sequenced and analyzed with NCBI database. Among of 179 examined samples, 38(21.20%) were positive. The highest of positive cases were found in kidney (28.60%). PCR-RFLP of SAG2 and GRA6 genes demonstrated the alleles of clonal type III in the all of isolates. Sequence analysis of the amplicons revealed the alleles of clonal type III and atypical isolates (Tg-67, Tg-100 and Tg-106). Phylogenetic analyses showed separate clade for the atypical isolates from others in the present study and the reference strains clades. In conclusion, the genetic characterization of T. gondii isolates from sheep and cattle showed high genetic diversity compared with standard type I, II and III genotypes. These results support the hypothesis of the existence of polymorphic and overlapping strains within livestock in Iran. It also suggested the necessity of increased genotyping and sampling efforts to accurately estimate T. gondii intra specific genetic diversity.

Development and evaluation of indirect enzyme-linked immunosorbent assay using recombinant dense granule antigen 7 protein for the detection of Toxoplasma gondii infection in cats in Thailand

Background and Aim:

Toxoplasma gondii is recognized as a zoonosis causing toxoplasmosis in animals globally. Cat is a definitive host of T. gondii and sheds oocyst through feces, which can infect human beings and animals through contaminated food ingestion. A precise diagnostic test is essential to prevent T. gondii infection in both humans and animals. This study aimed to develop and evaluate the pETite-dense granule antigen 7(GRA7)-based indirect enzyme-linked immunosorbent assay (ELISA) to detect T. gondii infection in cats.

Materials and Methods:

T. gondii-GRA7 was cloned and expressed in the Expresso^®small ubiquitin-related modifier (SUMO) T7 Cloning and Expression System. The recombinant pETite-GRA7 was purified using HisTrap affinity chromatography and confirmed using Western blot analysis. The recombinant protein was used to develop and evaluate the indirect ELISA for T. gondii infection detection. In total, 200 cat sera were tested using pETite-GRA7-based indirect ELISA and indirect fluorescent antibody test (IFAT). The statistical analysis based on Kappa value, sensitivity, specificity, positive predictive value, negative predictive value, χ² test, and receiver operating characteristic (ROC) curve was used to evaluate the performance of the test.

Results:

A 606 bp GRA7 polymerase chain reaction (PCR) product was obtained from T. gondii RH strain genomic DNA. The gene was cloned into the pETite™ vector and transformed to HI-Control Escherichia coli BL21 (DE3) for protein expression. Approximately 35 kDa of recombinant pETite-GRA7 was observed and Western blot analysis showed positive bands against anti-6-His antibody and positive-T. gondii cat serum. A sample of 0.5 μg/mL of pETite-GRA7 was subjected to indirect ELISA to detect T. gondii infection in the cat sera. The results showed sensitivity and specificity of pETite-GRA7-based indirect ELISA at 72% and 96%, respectively. An acceptable diagnostic performance was characterized by high concordant results (94%) and substantial agreement (Kappa value=0.65) with IFAT. The seroprevalence levels of ELISA and IFAT were 10% and 9%, respectively, and were not significantly (p>0.05) different. The expected performance of ELISA at different cutoff points using the ROC curve analysis revealed 89% sensitivity and 92% specificity at the cutoff value of 0.146, with a high overall assay accuracy (area under the curve=0.94).

Conclusion:

In this study, the pETite™ vector, N-terminal 6xHis SUMO fusion tag, was used to improve the solubility and expression level of GRA7. The recombinant pETite-GRA7 showed enhanced protein solubility and purification without special condition requirements. This pETite-GRA7-based indirect ELISA showed high concordant results and substantial agreement with IFAT. ELISA revealed an acceptable sensitivity and specificity. These initial data obtained from cats’ sera demonstrated that pETite-GRA7-based indirect ELISA could be a useful method for local serological diagnosis of T. gondii infection in cats in Thailand.

A Meta-Analysis of the Prevalence of Toxoplasmosis in Livestock and Poultry Worldwide

Toxoplasma gondii causes toxoplasmosis with a global prevalence in the world. A large proportion of human illness is most frequently associated with consuming raw and undercooked meat or other animal products containing infective parasitic stages of T. gondii. This systematic review and meta-analysis study evaluated the prevalence of toxoplasmosis in cattle, sheep, camels, goats, and poultry worldwide. The search was performed in databases including PubMed, WoS, Scopus, Science Direct, Google Scholar, and ISC from 2000 to 2019 in Persian and English. The main inclusion criteria were the prevalence of toxoplasmosis among livestock and poultry and the prevalence indices by sample size. During these 20 years, the overall prevalence of toxoplasmosis in livestock and poultry was 28.3% (95% confidence interval (CI) 25-31.9%) using the random-effects meta-analysis model. The highest prevalence of T. gondii in livestock and poultry animals was found in Asia in 2014 with 89.8% (95% CI 78.5-95.5%). The lowest prevalence was found in Asia in 2013 with 1.26% (95% CI 0.4-3.8%). A quarter of livestock and poultry were infected with T. gondii. Since livestock products are globally important sources of people's diet, our findings are useful for policymakers to control T. gondii infection in livestock.

PCR-based detection of Toxoplasma gondii from cattle in southern Iran

OBJECTIVE

Toxoplasma gondii is a protozoan parasite that is widely prevalent in most warm-blooded vertebrates. Humans mainly become infected by eating raw or undercooked meat. This study was designed to investigate the infection of cattle with T. gondii in Jahrom, southern Iran.

METHODS

Tissue samples consisting of heart, diaphragm, and tongue were collected from 125 slaughtered cattle. DNA samples were extracted from the homogenized tissues. T. gondii was detected and genotyped using nested-polymerase chain reaction (Nested-PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based on GRA6 and SAG2 (3', 5' terminal regions) genes, respectively.

RESULTS

The prevalence of T. gondii DNA was 56% in cattle. The most infected tissue was the diaphragm (54.4%) followed by the heart (48.8%) and tongue (43.2%). Type II was the most prevalent genotype (70%) among T. gondii isolates.

CONCLUSION

In this study, the high prevalence of T. gondii infection in cattle meat indicates the important role of cattle in the transmission of infection to humans. Therefore, incorporating the correct method of consuming meat in health education programs is crucial to prevent human infection.

Molecular and serological detection and of Toxoplasma gondii in small ruminants of southwest Iran and the potential risks for consumers

Toxoplasmosis is one of the most important zoonotic diseases with serious health risks for humans, especially for immunodeficient patients, and can lead to abortion in pregnant women worldwide. The oral uptake of sporulated oocysts and/or consumption of undercooked/raw meat of animals infected with Toxoplasma gondii can infect other animals and humans. Heart, liver, and meat tissues of 150 sheep and 150 goats from a slaughterhouse in Ahvaz, Iran, were collected during autumn 2018 and analyzed via polymerase chain reaction (PCR) to detect parasitic DNA in the animal tissues. Moreover, antibodies against T. gondii of 150 sera samples were detected as the targets by in-house enzyme-linked immunosorbent assay (in-house ELISA). A total of 26 (17.3%), 33 (22%), and 48 (32%) of liver, meat, and heart samples in sheep, and a total of 24 (16%), 26 (17.3%), and 36 (24%) of liver, meat, and heart samples in goats, respectively, showed positive PCR results. Besides, the ELISA evaluation of sera samples from 150 sheep and 150 goats resulted in 26 (13.3%) and 16 (10.6%) positive cases, respectively. A significant difference was also found between PCR-positive heart samples and ELISA-positive sera samples of both animal species (p < 0.05), but no significant difference existed between PCR-positive liver samples and ELISA-positive sera samples of both species (p > 0.05). The results of this study confirm the presence of T. gondii in sheep and goats’ consumable organs, highlighting the need to avoid consuming raw or uncooked organs of these animal species to prevent human infection with T. gondii.

Prevalence of endo- and ecto-parasites of equines in Iran: A systematic review

Equines are subject to infection with many parasites, which threaten their health. In the present study, we systematically reviewed existing literature on the prevalence of endo- and ectoparasites of equines in Iran. Major electronic databases, including PubMed, PubMed Central, Google Scholar, Science Direct and Scientific Information Database (SID), were searched (Last updated 11/05/2018) for relevant literature of parasites that have been identified from equines in Iran. Of the 1809 titles produced by bibliographic search, 38 were included in the review. Twenty-seven of the studies were on horses, six on donkeys, three on both horses and donkeys, and one study was on both horses and mules. Furthermore, 24 of the studies reported infections caused by protozoa, thirteen by helminths, two by ectoparasites, and one by both protozoa and helminths. The overall pooled prevalence of parasitic infection was 28.8% (95%CI: 22.9-35.7, I²  = 93.4%). Helminths were the most prevalent parasites 46.7% (95% CI: 24.1-70.7, I²  = 96.0%). Furthermore, donkeys were the most affected equine, with a prevalence of 70.7% (95% CI: 53.2-83.7, I²  = 92.5%). The protozoa frequently reported included nine species belonging to the genera: Neospora, Toxoplasma, Theileria, Babesia and Eimeria. Also, the helminths frequently reported included 21 species belonging to the genera: Strongylus, Dicrocoelium, Oxyuris, Habronema, Echinococcus, Dictyocaulus, Cyathostomum, Probstmayria, Anoplocephala, Setaria and Fasciola. Ticks were the only ectoparasites frequently reported. Parasitic fly species of the genera Gasterophilus were also reported. The study-level risk of bias was likely to be high because of differences in study design. Parasitic infections of equines in Iran are frequent and caused by a diversity of parasites, which threatens the health and well-being of these animals. Further research is needed in the area to identify the risk factors of infection for effective control of the parasites.

Economic and public health importance of Toxoplasma gondii infections in sheep: 2009-2020

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, diagnosis, control, and genetic diversity of T. gondii in sheep in the past decade. There is debate and uncertainty concerning repeat congenital infection as evidenced by finding T. gondii DNA in progeny of chronically infected sheep. However, there is no concrete evidence that T. gondii is the cause of repeated abortions in sheep. Recent data concerning pathogenesis of abortion in acutely infected sheep are reviewed. PCR-RFLP typing of T. gondii DNA derived from viable T. gondii isolates or tissues of infected sheep revealed low genetic diversity in sheep in Europe, Africa, Asia and North America but high diversity in South America. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Seroprevalence and Risk Factors of Toxoplasma gondii in Ruminant Meats from Wet Markets in Klang Valley and Abattoirs in Selangor, Malaysia

Simple Summary

This study investigated the prevalence of Toxoplasma. gondii in meats of cattle, goat and sheep from wet markets and abattoirs in Selangor, Malaysia. Meat samples from wet markets in various districts and diaphragm samples from abattoirs were analyzed using ELISA to check for T. gondii IgG antibodies. Furthermore, attempts were made to detect T. gondii DNA from meat samples using the nested PCR technique. Twenty-five percent of the samples were positive for T. gondii antibodies, with the highest recorded in goat (55%), followed by sheep (35%) and cattle meat (9%). T. gondii DNA was not detected in any of the meat samples. Being the first report in Malaysia, the findings highlight the need for proper control in reducing exposure of ruminant meats to the parasite, especially those destined for human consumption.

Abstract

(1) Background: The objective of this study was to determine the prevalence of T. gondii in meats of cattle, goat and sheep from wet markets in Klang Valley, and abattoirs in Selangor, Malaysia; (2) Methods: A total of 192 meat samples were purchased from 51 wet markets in six districts in Klang Valley (Gombak, Klang, Kuala Lumpur, Hulu Langat, Petaling and Putrajaya). Meanwhile, a total of 200 diaphragm samples were collected from two government abattoirs located in Shah Alam and Banting, Selangor. All meat juices from samples were subjected to an indirect-ELISA kit for the presence of T. gondii IgG antibodies. Furthermore, all 184 meat samples of goat and sheep were subjected to conventional nested PCR (B1 genes) for the detection of T. gondii DNA; (3) Results: T. gondii antibodies were detected in 25% (n = 98/392) of the samples with seroprevalence of 9.1% (19/208, CI: 5.9%–13.8%) in cattle meat; 54.7% (41/75, 95% CI: 43.5%–65.4%) in goat meat and 34.9% (38/109, CI: 26.6%–44.2%) in sheep meat. No T. gondii DNA was detected in any of the meat samples of goat and sheep. T. gondii seropositivity in wet market samples was higher in goat (OR = 37.1 CI 12.4–110.3) and sheep meat (OR 9.03 CI: 3.28–24.8) compared to cattle meat (OR = 1.0) At univariate level, meat from non-licensed abattoirs (OR = 6.0 CI: 2.9–12.3) and female animals (OR = 6.7; CI 1.9–22.6) had higher risks of being seropositive for T. gondii antibodies than licensed abattoirs and male animals, respectively. (4) Conclusions: This is the first report of seroprevalence of T. gondii in ruminant meats for human consumption in Malaysia. The findings signified high exposure of meat samples from wet markets to T. gondii and the need for control measures to reduce the likelihood of infection when such raw or undercooked meats are consumed.

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.

Molecular detection of Toxoplasma gondii from aborted fetuses of sheep, goats and cattle in Bangladesh

The study was planned to apply the PCR method for detection of T. gondii infection in sheep, goats and cattle aborted fetuses from Mymensingh, Bangladesh. A total of 58 fetal tissue samples (brain, liver, heart, skeletal muscle and placenta) of sheep (5), goats (5) and cattle (2) were selected for study. Aborted fetuses were taken from serologically positive mothers by indirect ELISA. Among them 24 and 34 samples were subjected for PCR assay by using TgB1 and TgTox4 primers respectively. DNA fragments were visualized under UV illumination after gel run. The results demonstrated 15.52% tissue samples from sheep and goat aborted fetuses were positive for T. gondii parasite. Among different tissue samples, brain, liver and heart showed presence of T. gondii parasite. None of tissue samples showed positive in case of cattle. The results of the PCR exhibited that T. gondii infection might be considered as one of the major causative agents for abortion in ewes and does. Further studies are needed to improve our knowledge on different genotypes of T. gondii that infect sheep, goat and cattle population in Bangladesh.

Risk factors associated with seropositivity to Toxoplasma among sheep and goats in Northern Iraq

Serum samples from 423 small ruminants (335 sheep and 97 goats) from 72 farms in 6 districts in the province of Dohuk, north Iraq, were tested for the presence of antibodies against Toxoplasma gondii using a latex agglutination test (Latex) and an indirect enzyme-linked immunosorbent assay (iELISA). When the test results were interpreted in parallel, 42.1% (95% confidence interval (CI): 36.7, 47.7) of sheep and 36.1% (95% CI: 26.6, 46.5) of goats were found to have antibodies against Toxoplasma. A multivariable logistic regression model was developed to determine the risk factors for Toxoplasma seropositivity in small ruminant flocks. Factors which increased the risk of infection included the presence of cats near the feed of animals (Odds ratio (OR) = 6.3; 95% CI 1.6, 24.6) and a history of abortions in sheep in the preceding 12 months (OR = 13.4; 95% CI 2.1; 86.7). For every ten goats aborting in the preceding 12 months the odds of seropositivity increased significantly (OR = 6.7; 95% CI 1.3; 32.9). Results of the regression model indicate that for every 1000 Iraqi Dinars (~0.85 USD) spent by the farmers on prophylactic treatment in their flocks the odds of Toxoplasma seropositivity decreased significantly (OR = 0.94; 95% CI 0.90, 0.98). This study contributes to the epidemiology of toxoplasmosis in small ruminants in northern Iraq.

Detection of Toxoplasma gondii in cat's internal organs by immunohistochemistry methods labeled with-[strept] avidin-biotin

AIM

The aims of the study are to detect the presence of Toxoplasma gondii antigen and to determine its distribution location in several organs of domestic cat using immunohistochemistry (IHC) method with Labeled-[Strept] Avidin-Biotin (LAB-SA).

MATERIAL AND METHODS

Four domestic cats aged 1-2 years were used as sample in this research. The sample divided into two groups with two cats each. Cats in Group I were positive Toxoplasma based on serologically screening test, while cats in Group II were orally infected with 1×106Toxoplasmaoocyst. All samples then necropsied, and the organs including brain, liver, kidney, duodenum, jejunum, ileum, lungs, and spleen were collected for IHC method with LAB-SA.

RESULT

The result showed that Toxoplasma antigens were detected in ileum of both serologically positive domestic cat and the experimentally infected cats. Toxoplasma was also observed in kidney of serologically positive domestic cat. In the serologically positive domestic cat, necrotic lesions were found on ileum, kidney, and liver, whereas in experimentally infected cat, the lesion was only found on ileum.

CONCLUSION

The presence of Toxoplasma antigen is successfully detected in several organs of domestic cat using IHC method with the LAB-SA.

Toxoplasma gondii Type I, predominant genotype isolated from sheep in South of Iran

Aim:

This study was performed to determine the genetic diversity of Toxoplasma gondii in sheep using nested-polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in Southern Iran.

Materials and Methods:

The tissue samples of diaphragm and heart from 125 sheep were collected from the main slaughterhouses of Jahrom district in South of Fars province, Iran, between Aprils and June 2013. The DNA were extracted and analyzed by nested-PCR using specific primers for SAG2 and GRA6 loci. RFLP was used to classify strains into one of the three major lineages of T. gondii.

Results:

T. gondii Type I was predominant in this area. The data obtained from both loci demonstrated that the frequency of each genotype was 72% Type I, 2.4% Type III, 7.2% mixed Type I and II, 16.8% mixed Type I and III, 0.8% mixed Type II and III, and 0.8% mixed Type I, II and III.

Conclusions:

Although the previously published data indicated that Type II is the predominant T. gondii genotype in sheep in the other parts of the world, this study showed that genotype I is the dominant genotype of T. gondii in the southern Iran; however, other genotypes were detected. High diversity of T. gondii genotypes including mix genotypes in lambs is of importance for the public health. These studies depict a new mapping of T. gondii genotypes pattern which could be very helpful in toxoplasmosis control and prevention.