Toxoplasma gondii infection among sheep and goats in Iran: A systematic review and meta-analysis

Newly optimized ELISA kit and LAT reveal significantly higher seroprevalence in sheep raised in agro-ecological zone as against range-ecological zone, with a significant association of meteorological parameters

BACKGROUND

Toxoplasma gondii is a zoonotic and foodborne intracellular parasite capable of inducing congenital infections, stillbirths and abortions in humans and animals, globally. The consumption of undercooked or raw mutton is "one of the vital risks" for acquiring toxoplasmosis: an asymptomatic condition in healthy persons, while life-threatening in immunodeficient individuals like "HIV/AIDS" patients.

OBJECTIVES

The current study has multiple objectives: to optimize a newly ELISA kit for Sheep, to find out the seroprevalence of ovine toxoplasmosis of two ecological zones of the Punjab, Pakistan through LAT and newly Optimized Sheep ELISA kit, to do the comparison of efficacies of various tests (LAT with newly Optimized ELISA kit and newly Optimized ELISA kit with commercial ELISA kit) and to determine the different meteorological parameters as the risk factors for T. gondii infection in sheep.

METHODS

A cross-sectional study was conducted on 400 sheep sera, 200 were collected from sheep raised on open grazing system by local farmers in the adjoining areas of Civil Veterinary Dispensaries (CVDs) of range-ecological zone i.e. tehsil Kot Chutta (Dera Ghazi khan). Similarly, the remaining 200 were collected from agro-ecological zone i.e. tehsil Sharaqpur (Sheikhupura), to evaluate the comparative efficacy of LAT with optimized ELISA kit and newly optimized ELISA kit with commercial ELISA kit.

FINDINGS

The newly ELISA kit optimized against a commercial ELISA kit was found to have 100% sensitivity, 97.6% specificity with 98% Positive Predictive Value, 100% Negative Predictive Value, Cut off value = 0.505, 28.28 LR+, 0.0104 LR-, and 2719.23 DOR. Seroprevalence of toxoplasmosis was detected significantly (P < 0.01; χ2) higher in Sharaqpur (44.5% by LAT; 35.5% by ELISA) as compared to that in Kot Chutta (39.5% by LAT; 31% by ELISA). The highest seroprevalence was seen in the sheep of the 1-2 years age group (P < 0.01; χ2), whereas the lowest in the oldest animals (≥ 4 years). Investigation of meteorological data of both the regions reveals that the zone with higher seroprevalence has relatively higher rainfall, higher humidity, lower environmental temperatures, and higher altitude as the critical factors, potentially behind the significant difference seen in seroprevalence level. The partial correlation of both tests (newly optimized ELISA kit and LAT) was 0.991 at maximum temperature in Sharaqpur while it was 0.981 in Kot Chutta.

INTERPRETATION

A novel significant correlation was found between the meteorological parameters (relative humidity, minimum, maximum, and average temperatures) divided into yearly units of both the ecological zones, and year-wise seroprevalence (birth years of age-wise groups) of the corresponding regions. We hypothesize that such environmental conditions increase the risk of toxoplasmosis in grazing sheep, owing to a more favorable environment for coccidian oocyst survival. The ELISA kit optimized in this study will be helpful for the detection of seroprevalence of ovine toxoplasmosis in other ecological zones of Pakistan as well as of any other country in the world. More studies are recommended involving regions from other ecological zones of Pakistan to further explore the seroprevalence of ovine toxoplasmosis and to ratify the novel correlation of meteorological parameters with seroprevalence.

Molecular Detection of Toxoplasma gondii in Blood Samples of Domestic Livestock in the Republic of Korea

Toxoplasma gondii, a major zoonotic pathogen distributed worldwide, causes severe infections in humans, animals, and birds. However, limited information is available regarding T. gondii infection in livestock in the Republic of Korea (ROK). Herein, we determined the prevalence of T. gondii infection in livestock in the ROK and identified animal species that can potentially transmit T. gondii to humans. B1 gene-targeting nested polymerase chain reaction detected T. gondii DNA in 3.3% (2/61), 2.9% (3/105), 14.1% (11/78), and 15.4% (14/91) of dairy cattle, beef cattle, Boer goats, and Korean native goats, respectively. The prevalence of T. gondii was significantly higher (p = 0.002) in goats than in cattle. The risk of contracting T. gondii infection was significantly higher by 6.18-fold in Korean native goats (95% confidence interval [CI]: 1.72–22.27%, p = 0.005) and by 5.58-fold in Boer goats (95% CI: 1.50–20.76%, p = 0.010) than in beef cattle. Our T. gondii DNA sequences exhibited 97.1–100% homology with those obtained from various hosts in other countries. To the best of our knowledge, this is the first study to report T. gondii infection using the blood samples of domestic ruminants in the ROK. The results revealed that the prevalence of T. gondii infection is higher in goats than in cattle as determined by molecular detection. Thus, these findings suggest that T. gondii can be transmitted from ruminants to humans via meat consumption.

Prevalence of Toxoplasmosis in Sheep and Goats in Pakistan: A Systematic Review and Meta-Analysis

Toxoplasmosis, a parasitic disease caused by Toxoplasma gondii, results in congenital disorders and miscarriages among livestock and humans worldwide. This systematic review and meta-analysis were conducted to determine the prevalence of T. gondii infection in sheep and goats in Pakistan from 2000 to 2020. We searched the PubMed, Scopus, EMBASE, and Google Scholar databases and selected 17 publications that fulfilled our inclusion criteria. Eight studies were conducted in Southern Punjab, six in Khyber Pakhtunkhwa, two in Northern Punjab, and one in Central Punjab. The diagnostic tests used in the included articles to confirm toxoplasmosis were the latex agglutination test in 56% of the studies, the enzyme-linked immunosorbent assay in 38%, and the indirect hemagglutination assay in 6%. The infection rates were substantially higher among sheep > 1 year of age (37%) than among sheep ≤ 1 year old (19%). Statistically significant differences in infection rates were found between male and female sheep and goats. The overall infection rate by age was also significant among sheep and goats. Sex and age variability between sheep investigations were significant, and sex heterogeneity and age homogeneity were significant among goats. Hence, robust infection control protocols should be implemented to prevent infection in animals and 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.

Causes of abortion in Iranian sheep flocks and associated risk factors

Abortion is a major issue in sheep husbandry. It can result in significant economic losses and a severe public health risk. This survey assessed the infectious and non-infectious causes of abortion in Iranian sheep flocks and determined the main risk factors. In this cross-sectional survey, causes of abortion were evaluated in 757 sheep flocks, and risk factors were analysed. A checklist containing general animal information for each abortion outbreak evaluated was filled in. Data were analysed using univariate tests and multivariable binary logistic regression analysis. In this sense, parity, gestational age of the aborted fetus, vaccination protocol, mineral supplementation and history of stillbirth showed significant associations with abortion. Infectious agents such as Coxiella burnetti (22.7%), Chlamydia abortus (12.3%) and Brucella melitensis (10.4%) were the most frequently isolated in the investigated flocks, with more than 2% of abortion rates. On the other hand, non-infectious agents such as trauma, pregnancy toxaemia and vitamin E/Se deficiency were involved in those flocks with low abortion rates (less than 10%). Results revealed multiple causes of abortion outbreaks among Iranian sheep flocks, which need careful investigation to identify possible aetiology and risk factors. Further studies are necessary to evaluate if these factors are similar to other countries in the same region.

Genetic characterization of Toxoplasma gondii in meat-producing animals in Iran

BACKGROUND

The consumption of uncooked or undercooked food from infected intermediate hosts can result in Toxoplasma gondii infection in humans. However, few studies have investigated the genetic diversity of this protozoan parasite in Iran. The aim of the present study was to genetically characterize isolates of T. gondii from intermediate host animals in Mazandaran Province, Iran.

METHODS

Blood and heart tissue samples were collected from 204 ruminants, and brain tissue was collected from 335 birds. The prevalence of T. gondii infection in these samples was determined serologically using the modified agglutination test and by conventional PCR assays. Those PCR samples positive for T. gondii DNA and 13 DNA samples extracted from aborted fetuses in a previous study were genotyped with 12 genetic markers using the multilocus-nested PCR-restriction fragment length polymorphism (Mn-PCR-RFLP) technique.

RESULTS

Antibodies for parasites were found in 35.7% of the ruminant (39.1% of sheep and 26.4% of goats) samples and in 51.3% of the bird (100% of geese, 52.3% of free-range chickens and 46% of ducks) samples. Molecular detection by PCR of the repetitive 529-bp DNA fragment revealed contamination of 13.2% of ruminant (14.6% of sheep and 9.4% of goats) samples and of 9.6% of bird (11.1% of chickens, 5.7% of ducks and 0% of geese samples). The results from 30 DNA samples revealed five ToxoDB (genome database for the genus Toxoplasma) PCR-RFLP genotypes, including #1 (Type II), #2 (Type III), #10 (Type I), #27 and #48, with genotype #1 the most predominant.

CONCLUSIONS

As evidenced by the results of this study, ruminants and birds are infected with T. gondii in the region, suggesting that they are likely to be involved in the transmission of T. gondii to humans through meat consumption. The identification of different genotypes may suggest a higher genetic diversity of this parasite in Mazandaran, reflecting local environmental contamination. These results have important public health implications for the prevention and control strategies of infection.

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.

Geospatial epidemiology of Toxoplasma gondii infection in livestock, pets, and humans in China, 1984-2020

Undercooked or raw meat containing cyst-stage bradyzoites and oocyst-contaminated pets are presumed to constitute a major source of human toxoplasmosis. As the geospatial epidemiology of Toxoplasma gondii (T. gondii) infection in livestock, pets, and humans is rarely studied in China, we undertook a geospatial analysis using GIS visualization techniques. The present study retrieved information from the PubMed, China National Knowledge Infrastructure, and Baidu Scholar databases from 1984 up to 2020. All the data about the seroprevalence of T. gondii in livestock (sheep and goats, pigs, cattle and yaks), pets (cats, dogs), and humans in China were collected. Geospatial epidemiology of T. gondii infection in these hosts was performed using GIS. Results revealed that the estimated pooled seroprevalence of T. gondii was ranged from 3.98 to 43.02% in sheep and goats in China, 0.75 to 30.34% in cattle and yaks, 10.45 to 66.47% in pigs, 2.50 to 60.00% in cats, 0.56 to 27.65% in dogs, and 0.72 to 23.41% in humans. The higher seroprevalences of T. gondii were observed in sheep and goats in the districts of Chongqing, Zhejiang, and Beijing. The infection rates of T. gondii in cattle and yaks were higher in Guizhou, Zhejiang, and Chongqing. Also, the pigs from Chongqing and Guizhou were most severely infected with T. gondii. For cats, the districts of Shanxi, Hebei, and Yunnan had higher seroprevalences of T. gondii and, the infections among dogs were higher in Yunnan and Hebei as well. Furthermore, higher infection pressure of T. gondii exists in the districts of Taiwan and Tibet in humans. The geographical and spatial distribution of toxoplasmosis indicated that infection with T. gondii was widely spread in China, with a wide range of variations among the different hosts and regions in the country. Our results suggested that livestock and pets are not only a reservoir for the parasite but also a direct source of T. gondii infection for humans. It is important to control T. gondii infections in these animals that would reduce the risk of toxoplasmosis in humans.

The prevalence of Toxoplasma gondii in sheep in China: A systematic review and meta-analysis

Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii, which is widespread in warm-blooded animals and humans. Currently, many studies regarding T. gondii infection in sheep have been published worldwide. However, there is no meta-analysis of sheep infection in China. In this study, five databases were used to retrieve articles related to T. gondii in China. A total of 59 studies from 1987 to June 30, 2020, have been included. We estimated that the combined prevalence of T. gondii in the selected period was 8.5% (3197/28,099). In the analysis of publication year, the lowest positive rate after 2010 was 7.4% (1883/17,313). Geographically, the highest prevalence of T. gondii in sheep was recorded in Southwest China 19.2% (490/2080). Analysis according to age showed that the prevalence of infection in sheep older than 12 months was significantly (P < 0.05) higher than that in younger animals. The prevalence of T. gondii in sheep farmed by farmers was 7.2% (566/6336), which was higher than 5.3% (660/3121) of large-scale farming, suggesting a role for the feeding and husbandry. We also analyzed the impact of different geographic and climatic factors on the prevalence of T. gondii infection in sheep. The results showed that the prevalence was higher in low altitude, warm, humid, and high rainfall areas. We suggest that appropriate control programs should be formulated according to the differences in reproduction patterns and geographical conditions in different regions to reduce the prevalence of T. gondii among sheep in China.

Designing and developing of high-resolution melting technique for separating different types of Toxoplasma gondii by analysis of B1 and ROP8 gene regions

BACKGROUND

Determination of Toxoplasma gondii genotypes plays an important role in the health management and epidemiology of toxoplasmosis. We developed HRM analysis to differentiate genotypes of T. gondii using the B1 and ROP8 genes, through comparing the sensitivity and specificity of both genes and methods used for the detection of T. gondii.

METHODS

A total of 96 DNA samples of muscle tissue of livestock and poultry brain tissue with three standard strains RH (type I), PRU (type II) and VEG (type III) were prepared and analyzed. Three methods of nested PCR, PCR-PCR and nested-qPCR-HRM were used. Specific new primers were designed and synthesized for developing HRM. Thirty positive samples obtained from nested-qPCR-HRM were sequenced (18 B1 and 12 ROP8).

RESULTS

Overall, 87 infected samples were identified using both genes. Through the B1 gene, we could separate type I (T_m = 84.8 °C) from II/III types (T_m = 84.6 °C). Also, the ROP8 gene could separate type II (T_m = 84.5 °C) from I/III types (T_m = 84.12 °C). Highest sensitivity (100%) and specificity (78.72%) were observed by nested-qPCR-HRM assays of the B1 and ROP8 genes than by other methods, respectively. Thus, the B1 gene can be used to most accurately detect T. gondii, while the ROP8 gene was more appropriate for T. gondii genotyping. PCR-sequencing results were consistent with HRM results in most selected samples.

CONCLUSION

HRM analysis is a powerful diagnostic tool for rapid detection and determination of main clonal lineages, and even unusual T. gondii genotypes.

Toxoplasma gondii in Sheep and Goats from Central Iran

OBJECTIVE

Toxoplasmosis, caused by Toxoplasma gondii, infects humans by consuming infected raw or undercooked meat and foods harboring mature oocysts. In this study, we assessed the prevalence of T. gondii in sheep and goats coming from central Iran. After completing the questionnaire, about one gram of liver or diaphragm tissue was taken as a sample from 90 sheep and 90 goats slaughtered in Yazd Province and stored at - 20 ºC. DNA extraction was done, and then T. gondii was detected using nested PCR.

RESULTS

This study indicated that the prevalence of T. gondii in all slaughtered animals was 11.6% (21 of 180), including 14.4% (13/90) in sheep and 8.8% (8/90) in goats. The infection rates in liver and diaphragm samples were 12.2% (11/90) and 11.1% (10/90), respectively (p = 0.8163). The infection rate in animals older than one was 16.3% (15/92), and it was 6.8% (6/88) in animals under one year of age. Therefore, no significant differences were found (p = 0.475). Infection rates were 19.5% (18/92) in males and 3.4% (3/88) in females (p = 0.0007). In conclusion, the infection rates of toxoplasmosis in livestock in this area are almost high, and therefore, it is necessary to design appropriate prevention programs to control the disease.

Epidemiological Survey of Toxoplasma gondii and Associated Risk Factors in Ruminant Species of the Khyber Pakhtunkhwa Province of Pakistan

Toxoplasma infection is one of the most common human parasitic diseases. During 2018-2020, in the rural areas of three districts of Pakistan, we surveyed a total of 451 animals, belonging to different asymptomatic ruminant species, to determine the prevalence of Toxoplasma gondii antibodies. We used ELISA assay as well as recorded some associated risk factors contributing to its transmission. IgM antibodies were detected in 17% and IgG in 13.4% of ruminant samples with the highest percentage, 10% for IgM and 8.6% for IgG in sheep. A strong significant association was found between antibodies and different species (IgM, ${\chi }^2=29$ .280, $P=.000$ , and IgG, ${\chi }^2=22.580$ , $P=.000$ ), respectively. Infection with T. gondii seems mainly associated with different geographic features and the presence of cats in the environment, low hygiene water systems and livestock that are mostly dependent on outdoor drinking and grazing. There was no significant association between IgM and age grouping ( ${\chi }^2=6.660$ , $P=0.840$ nor for IgG ( ${\chi }^2=8.136$ , $P=0.43$ ). The results of this study may be considered the starting point to promote the awareness about parasitic infections in ruminants in Pakistan in order to prevent this infection from further spreading.

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.

Serological Determination of Toxoplasma gondii among Sheep (Ovis aries) in Guilan Province, Iran

Toxoplasma gondii is one of the most common foodborne protozoan parasite causing congenital infection, abortion, and stillbirth in humans and animals. The temperate and humid climate is one of the most important factors in the high prevalence of T. gondii. Sheep are among the important sources of meat production in Guilan province, Iran. Therefore, the consumption of raw and half-cooked meat is one of the major risk factors for T. gondii infection. Toxoplasmosis in patients with intact immune systems is usually asymptomatic; however, it but can be life-threatening in patients with a weak immune system (for example, patients with the human immunodeficiency viruses/acquired immunodeficiency syndrome or cancer and transplant recipients). Guilan is divided into three geographical regions of plains with a temperate climatic condition, hillsides with a semi-humid climate, and heights with cold mountainous climate. Climate situations play a role in the prevalence of toxoplasmosis. The present study aimed to investigate the seroprevalence of T. gondii infection among sheep in Guilan province, north of Iran. In the current cross-sectional study, a total of 400 sheep sera samples were tested for the determination of immunoglobulin G (IgG) antibody against T. gondii using the enzyme-linked immunosorbent assay. The samples were divided into different groups according to the geographical location and animal age. T. gondii antibody (i.e., IgG) was detected in 166 sheep (41.5%). The highest frequency of T. gondii infection (72.7%; n=56) was observed for the age group of &amp;gt; 4 years; the difference was statistically significant in this regard (P=0.0001) in comparison to that reported for other groups. In addition, the seroprevalence of T. gondii was significantly higher in the plains (53.9%) than that of the hillsides and heights (P=0.0001). Consequently, the seroprevalence of T. gondii infection in Guilan was high indicating a significant relationship with geographical location and animal age.

Molecular Genotyping of Toxoplasma gondii in Sheep Aborted Fetuses Reveals Predominance of Type I Infection in Southwest of Iran

Background

We aimed to detect Toxoplasma gondii in ovine aborted fetuses and evaluate its genetic variations in the southwest of Iran.

Methods

This cross-sectional study was performed on 100 aborted ovine fetuses collected from the different region of Kohgiluyeh and Boyer-Ahmad Province, Iran, in lambing season during 2017 and 2018. DNA was extracted from the brain samples of all of the aborted fetuses and PCR amplified, targeting a 529 bp repetitive element gene of T. gondii. Moreover, to find out the heterogeneity of the positive samples, PCR-DNA amplification of the two main genetic markers, B1 and GRA6, of T. gondii were performed. Nucleotide sequencing and phylogenetic analysis were performed, using the BLAST program and MEGA-X software.

Results

The 529 bp gene of T. gondii was detected in 2 out of 100 (2%) of the ovine aborted samples. The sequences analysis of GRA6 and B1 genes revealed that both isolates from the aborted fetuses of sheep belonged to type I of T. gondii. Intra-divergence was more seen in GRA6 gene whereas less divergence was observed in B1 gene.

Conclusion

Congenital infection with Type I of T. gondii during the neonatal period is associated with abortion in ovine. Evaluation of more aborted samples from broader geographical areas is needed to elucidate the molecular epidemiology and also the genotypes of T. gondii associated with abortion.

Global Status of Toxoplasma gondii Seroprevalence in Rodents: A Systematic Review and Meta-Analysis

Toxoplasmosis is one of the most prevalent infections in humans and animals caused by the intracellular protozoan parasite Toxoplasma gondii (T. gondii). Rodents, as intermediate and reservoir hosts, play a key role in the maintenance and transmission of T. gondii. They can be contaminated and maintain the parasite in the form of cysts in their bodies, demonstrating an infection source for their offsprings, predators (particularly felids), and other animals. Therefore, the present systematic review and meta-analysis study was carried out to evaluate the global seroprevalence of T. gondii in these mammals. For achieving the purpose of the current study, six English databases (PubMed, Science Direct, Web of Science, Scopus, ProQuest, and Google Scholar) were systematically searched for related studies from 1970 to 2018. Finally, a total of 52,372 records were screened, 105 records including 26,221 rodents were incorporated in the present study. By random effect models, the overall seroprevalence was calculated at 6% (95% CI = 6-7%), with the highest amount was observed in Africa (24%) and South America (18%), and the lowest amount in Europe (1%). The subgroup data analysis by gender manifested that the prevalence of Immunoglobulin G antibodies did not differ between genders (P > 0.05). Due to the significant heterogeneity, meta-regression models were applied based on serological techniques and continental regions; however, the obtained values were not statistically significant (P = 0.480 and P = 0.295, respectively). The present study revealed a relatively low level of T. gondii seroprevalence in rodents; however, if they were the main food source for their predators, they would cause high transmission of T. gondii.

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.

Public health and economic importance of Toxoplasma gondii infections in goats: The last decade

Toxoplasma gondii infections are common in humans and animals worldwide. Toxoplasmosis in goats continues to be of public health and economic concern. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, treatment, and genetic diversity of T. gondii in goats in the past decade. There is debate and uncertainty regarding excretion of T. gondii in milk and the ingestion of raw milk as sources of T. gondii infection for humans. Toxoplasmosis can cause abortion and deaths even in adult goats. PCR-RFLP typing of T. gondii DNA derived from viable T. gondii isolates has revealed genetic diversity in goats in North and South America. The significance of T. gondii isolates in domestic goats usually associated with wildlife in USA is discussed. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Investigation of Toxoplasma gondii Infection in Aborted Fetuses of Sheep Using PCR: A Study in North Khorasan Province, Iran

Toxoplasma gondii is a zoonotic obligate intracellular protozoan parasite that infects warm-blooded animals as well as humans worldwide. The purpose of this study was to delineate the prevalence of Toxoplasma infection in aborted fetuses of sheep in North Khorasan province, Iran. Three hundred and ninety-nine samples of the liver (133 samples), placenta (133 samples), and brain (133 samples) from 133 aborted fetuses of sheep were collected from 2015 to 2017. The ages of aborted fetuses were higher than 120 days' gestational age in this study. According to the samples, sixteen out of 133 aborted fetuses of sheep were infected with T. gondii. Toxoplasma DNA was found in the placenta (68.75%) and liver (31.25%) samples of infected fetuses using the PCR method. The highest and lowest rates of Toxoplasma infection were observed during 2016 and 2017, respectively. Shirvan and Faruj provinces were recognized as the two most infected districts among others. There was a significant difference between the year and abortion rate in sheep due to infection by the Toxoplasma parasite (P < 0.05). Furthermore, no significant difference between the prevalence of T. gondii infection and aborted fetuses was seen (P > 0.05) in different areas. According to the present study, T. gondii infection can be one of the causes of fetus abortion of sheep in North Khorasan province, Iran.

Toxoplasma gondii Seropositivity and Associated Risk Factors in Cats (Felis catus) in Three Provinces in Northeastern China from 2013 to 2019

Toxoplasma gondii is an important protozoan parasite that can infect a range of animals. Cats are the most important definitive hosts for T. gondii. Therefore, an assessment of the level of T. gondii infection in cats is of public health importance. As limited information about seroprevalence of T. gondii infection in cats in northeastern China was available, 854 serum samples, including 235 cats in Jilin province, 267 cats in Liaoning province, and 352 cats in Heilongjiang province, were examined by an indirect hemagglutination assay (IHA) test, between September 2013 and July 2019. The overall seroprevalence of T. gondii was 19.09% (163/854) at the cutoff 1:64, with 19.60% (69/352), 18.29% (43/235), and 19.10% (51/267) in Heilongjiang, Jilin and Liaoning, respectively. Logistic regression analysis showed that mode of life was highly related to T. gondii infection in cats at the investigation areas. These results could provide foundation data for prevention and control of T. gondii prevalence in these regions. Moreover, the results also suggested that the effective control strategies should continue to be performed.

Molecular Diagnosis and Pathological Study of Toxoplasma gondii in Aborted Caprine and Ovine Fetuses in Borderline of Iran-Iraq

BACKGROUND

Infection with the protozoan parasite Toxoplasma gondii is widely prevalent in animals and humans. In goats and sheep this infection has a high economic impact as it causes abortions and lamb losses. Although there are several studies reporting seroprevalence in small ruminants in Iran, molecular-based information is scarce.

PURPOSE

This study aimed to screen caprine and ovine aborted fetuses for T. gondii infection by PCR and histopathology.

METHODS

Brains of 121 aborted fetuses (10 caprine and 111 ovine) were collected from different parts of the Kordestan province, bordering with Iraq. Gestational age and the general status of each fetus such as freshness, autolysis, mummification and presence of macroscopic lesions in the fetus and foetal membranes was recorded. Individual brain tissues of fetuses were subjected to nested-PCR targeting the B1 gene, and histopathological sections prepared from brains were examined microscopically.

RESULTS

PCR results revealed T. gondii-associated abortion in one caprine and nine ovine fetuses (8.3%). Microscopically, pathological lesions included non-purulent meningitis associated with gliosis, focal necrosis, and occasionally tissue cyst.

CONCLUSION

This paper reports for the first time T. gondii-associated abortion in goats in Iran. As organs from aborted fetuses do not necessarily show lesions, molecular confirmation is the unique diagnostic method and should be used in situations of an abortion epidemic.

Seroprevalence of Toxoplasma gondii in Cattle and Sheep in Isfahan, Iran

Background and aims: Toxoplasma gondii is an obligate intracellular parasite which has the potential to infect all warm-blooded animals. Sheep and cattle play a main role in the economy and their infection to T. gondii, besides economic losses, can cause the infection of humans through the consumption of raw meat and other products. In this study, we aimed to survey the prevalence of T. gondii in the livestock in Isfahan, Iran. Methods: A total of 384 samples including 144 sheep and 130 bovine serum samples from Isfahan and 50 sheep and 60 bovine serum samples from Kashan slaughterhouses were tested for the presence of T. gondii antibody using the indirect immunofluorescence method. Results: In general, the antibody was found in 27.31% of sheep and 22.63% of cattle at a dilution of ≥1:200. In detail, 26.15% of bovine and 26.17% of sheep serums from Isfahan and 15% of bovine and 22% of sheep serums from Kashan were seropositive. Conclusion: The study revealed that sheep and cattle can be a significant intermediate host for the spread of the disease in this region (Isfahan province) and the health and livestock authorities in the province should be given priority in improving animal welfare and nutrition.

IL-17 and IL-22 elicited by a DNA vaccine encoding ROP13 associated with protection against Toxoplasma gondii in BALB/c mice

Toxoplasma gondii, an intracellular parasitic protozoan, is capable of infecting man and all warm-blooded animals. Cell-mediated immunity is vital in mounting protective responses against T. gondii infection. Recent studies have shown that T-helper (Th) 17 responses may play a key role in parasite control. In this current study, we constructed a DNA vaccine encoding T. gondii ROP13 in a pcDNA vector. Groups of BALB/c mice were immunized intramuscularly with pcROP13 or controls and challenged with the RH strain of T. gondii. The results showed that immunization with pcROP13 could elicit an antibody response against T. gondii. The expression of the canonical Th17 cytokines, interleukin (IL)-17 and IL-22, were significantly increased after immunization with pcROP13 compared with control groups ( p < 0.05). Furthermore, vaccination resulted in a significant decrease in parasite load ( p < 0.05). The induction of Th17 related cytokines, using a ROP13 DNA vaccine, against T. gondii should be considered as a potential vaccine approach for the control of toxoplasmosis.

Calcium-dependent protein kinases are potential targets for Toxoplasma gondii vaccine

Toxoplasma gondii belongs to the Apicomplexa phylum that caused a widespread zoonotic infection in wide range of intermediate hosts. Over one-third of the world's population are latently infected with T. gondii and carry it. The complex life cycle of T. gondii indicates the presence of a plurality of antigenic epitopes. During the recent years, continuous efforts of scientists have made precious advances to elucidate the different aspects of the cell and molecular biology of T. gondii. Despite of great progresses, the development of vaccine candidates for preventing of T. gondii infection in men and animals is still remains a challenge. The calcium-dependent protein kinases (CDPKs) belongs to the superfamily of kinases, which restricted to the apicomplexans, ciliates, and plants. It has been documented that they contribute several functions in the life cycle of T. gondii such as gliding motility, cell invasion, and egress as well as some other critical developmental processes. In current paper, we reviewed the recent progress concerning the development of CDPK-based vaccines against acute and chronic T. gondii.

Fetomaternal and Pediatric Toxoplasmosis

Toxoplasmosis is one of the most important causes of foodborne illnesses and inflammatory complications, as well as congenital disorders. Promiscuous Toxoplasma is transmitted by contaminated food and animal produce, water, vegetations, fruits and sexually through semen. Toxoplasma infects nucleated cells with a unique tropism for muscles and central nervous system and a mind bugging malicious effect. Pregnant women with acute or reactivated toxoplasmosis can transmit Toxoplasma via transplacental to the fetus. The severity of congenital toxoplasmosis depends on the gestation period, as infection in early pregnancy causes more severe consequences. Congenital toxoplasmosis complications include miscarriage, encephalitis, neurological retardation, mental illnesses, auditory and visual inflammatory disorders, cardiovascular abnormalities, and pains. Current therapies are inefficient for congenital and chronic toxoplasmosis or have severe side effects with life threatening complications. There is an urgent need for effective and safe therapeutic modalities to treat complications of toxoplasmosis and effective vaccines to eliminate the infectious agent. This investigation will discuss pathogenesis of feto-maternal, congenital and pediatric toxoplasmosis, the current available therapies in practice, and explore those therapeutic modalities in experimental stages for promising future trials.

Birds and poultries toxoplasmosis in Iran: A systematic review and meta-analysis

OBJECTIVE

To evaluate the overall prevalence of Toxoplasma gondii infection among birds and poultries in Iran.

METHODS

Data were systematically collected from 1983 to 2016 in Iran on the following electronic databases: PubMed, Google Scholar, Science Direct, Scopus, Web of Science, Magiran, Irandoc, IranMedex, and Scientific Information Database. Additionally, the abstracts of national scientific congresses and dissertations were included.

RESULTS

A total of 20 articles in the field of birds and poultries toxoplasmosis, totally examining 4563 cases with 754 positive results reporting the overall prevalence of infection from all parts of Iran could fulfill our eligibility criteria. The overall estimated prevalence included in chicken 20% (95% CI: 3%-38%) in chicken, pigeons 8% (95% CI: -17%-33%) and in sparrows 15% (95% CI: -25%-54%).

CONCLUSION

Although there is a lack in data about poultries and birds toxoplasmosis in Iran, our meta-analysis revealed that infection rate is high among birds and poultries in Iran. More studies are needed to manage controlling programs and prevention strategies among poultries in Iran.

Toxoplasmosis seroprevalence in Iranian women and risk factors of the disease: a systematic review and meta-analysis

BACKGROUND

Toxoplasmosis is caused by an intracellular obligatory parasite, Toxoplasma gondii, and it has global distribution. The purposes of this systematic review and meta-analysis were to evaluate the seroprevalence of toxoplasmosis in Iranian pregnant women, and girls and women of childbearing age, and identify potentially preventable risk factors.

METHODS

Between November 2014 and February 2017, nine electronic databases that reported data on the T. gondii seroprevalence in Iranian women were searched. Our search resulted in 83 reports published from 1994 to 2017.

RESULTS

The results showed that the pooled estimation for the prevalence of T. gondii using a random-effect model was 43% (95% confidence interval (CI) = 38-48%) in pregnant women and 33% (95% CI = 23-43%) in girls and the childbearing age groups. There was a significant association between the T. gondii seroprevalence with age and the gestational age of conception in pregnant women and those who had contact with cats in both groups.

CONCLUSIONS

This is the first comprehensive systematic review of T. gondii infection seroprevalence in Iranian women, which showed a high prevalence of Toxoplasma infection. Around 57% of pregnant women and 67% of girls and the childbearing age groups were seronegative and thus were susceptible to infection and should be monitored.

Toxoplasma gondii infection in meat animals from Africa: Systematic review and meta-analysis of sero-epidemiological studies

AIM

Toxoplasma gondii is an ubiquitous apicomplexan parasite which causes toxoplasmosis in humans and animals. Felids especially cats are definitive hosts and almost all warm-blooded mammals, including livestock and human can serve as intermediate hosts. Food animals can be reservoirs for T. gondii and act as one of the sources for parasite transmission to humans. The objective of this study is to collect serological data on the prevalence of anti-T. gondii antibody, and risk factors for certain food animals from Africa to provide a quantitative estimate of T. gondii infection among these species from different African countries.

MATERIALS AND METHODS

Four databases were used to search seroepidemiological data on the prevalence of anti-T. gondii antibody in food animals between 1969 and 2016 from African countries. The search focused on data obtained by serologic test in food animals and meta-analyses were performed per species.

RESULTS

A total of 30,742 individual samples from 24 countries, described in 68 articles were studied. The overall estimated prevalence for toxoplasmosis in chicken, camel, cattle, sheep, goat, pig were 37.4% (29.2-46.0%), 36% (18-56%), 12% (8-17%), 26.1% (17.0-37.0%), 22.9% (12.3-36.0%), and 26.0% (20-32.0%), respectively. Moreover, major risk factor of infection was age, farming system, and farm location.

CONCLUSIONS

A significant variation in the seroepidemiological data was observed within each species and country. The results can aid in an updated epidemiological analysis but also can be used as an important input in quantitative microbial risk assessment models. Further studies are required for a better and continual evaluation of the occurrence of this zoonotic infection.

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.

SEROPREVALENCE AND RISK FACTORS ASSOCIATED WITH Toxoplasma gondii INFECTION AMONG RURAL COMMUNITIES IN NORTHERN IRAN

Toxoplasmosis is the fourth most common cause of hospitalization and the second cause of death due to food-borne infections. We conducted a cross-sectional study to determine the prevalence, disease awareness and risk factors associated with toxoplasmosis among rural communities in Northern Iran. Data were obtained from serological testing and from participant^'s questionnaires and were analyzed using a logistic regression. Of the 630 participants, 465 (73.8%), and 12 (1.9%) had IgG and both IgG and IgM anti-Toxoplasma gondii antibodies, respectively. In the logistic regression analysis, T. gondii seropositivity was associated with the following factors: age, occupation, consumption of undercooked meat, and of unwashed raw vegetables or fruits (p < 0.001). Our study showed a high prevalence of T. gondii infection in the general population of Northern Iran. A health program is needed to increase the public awareness of toxoplasmosis, and its associated risk factors.

Evaluation of the basic functions of six calcium-dependent protein kinases in Toxoplasma gondii using CRISPR-Cas9 system

Toxoplasma gondii, an important protozoan parasite, infects almost all warm-blooded animals and humans. Although treatments in T. gondii are limited by the lack of effective drugs, some calcium-dependent kinases were demonstrated as the promising drug targets to chemotherapy against T. gondii due to their essential roles in T. gondii and absence from their hosts. The objectives of the present study were to investigate the functions of six calcium-dependent protein kinases (CDPK4, CDPK4A, CDPK5, CDPK6, CDPK8, and CDPK9) in T. gondii to assess whether they are suitable for designing as drug targets. We used the CRISPR-Cas9 system to disrupt six CDPK genes successfully by insertion of DHFR* at the guide RNA-targeted region in the six endogenous CDPK loci and successfully obtained the six knockout (KO)-CDPK strains. The biological characteristics of the six strains were evaluated by plaque assays, invasion, egress, replication, and virulence assays, respectively. The results indicated that there was no significant difference between the six KO-CDPK strains and wild-type strain in virulence and the lytic cycle including invasion, egress, and replication. The conclusion was the six CDPKs are not essential for T. gondii lytic cycle and also not virulence factors for mice, suggesting that the six CDPKs may participate in other functions in T. gondii.

Seroprevalence of Toxoplasma gondii in the Iranian pregnant women: A systematic review and meta-analysis

Toxoplasmosis is a common and serious parasitic disease with high prevalence and global distribution in human and other warm-blooded vertebrates. Though the infection of Toxoplasma gondii is usually asymptomatic in healthy people, it can lead to severe pathological effects to the fetus of infected women and immunocompromised patients. So pinpointing the risk factors and control procedures are of important works among these populations. In order to reach this goal, we conducted a systematic review and meta-analysis to identify the seroprevalence rate of T. gondii infection among Iranian pregnant women population to achieve a comprehensive explanation of the disease condition in Iran for future use. English electronic databases (PubMed, Science Direct, Scopus, Ovid and Cochrane) and Persian language databases (Scientific Information Database, Iran Medex, Magiran and Iran Doc) were searched. Furthermore, the proceedings of Iranian parasitology congresses were explored manually. Our review resulted in a total of 50 publications meeting the inclusion criteria during Jan 1990-June 2015. Totally, 20221 women had been tested during this period of which 7724 women had seropositivity for IgG. According to results of heterogeneity test, either Der Simonian and Laird's random-effects method or Mantel-Haenszel's fixed-effects method were used to pool the estimations. Weighted overall prevalence of toxoplasmosis in pregnant women were obtained using random-effects model, which was estimated 41% (95% CI=36-45%). Also IgG and IgM antibodies was obtained 38% (95% CI=34-42%) and 4% (95% CI=3-5%), respectively. The highest and the lowest seroprevalence of toxoplasmosis in five geographical zones of Iran were observed in South 53% (95% CI=30-77%) and East 33% (95% CI=23-42%), respectively. In order to detect publication bias, Egger's regression test was done which revealed that publication bias might not have a significant influence on overall prevalence estimate (P=0.89). Multivariate analysis showed that there's a statistically significant correlation between toxoplasmosis and two risk factors including "place of residence" (P=0.005) and "contact with cat" (P=0.002). There was no significant difference between toxoplasmosis and the other surveyed risk factors. It is highly recommended to further study for the aim of better disease management and developing more efficient diagnostic tests.

Toxoplasmosis in Blood Donors: A Systematic Review and Meta-Analysis

Transfusion-transmissible infections include pathogens that may cause severe and debilitating diseases. Toxoplasmosis is a cosmopolitan neglected parasitic infection that can lead to severe complications including death in immune-compromised patients or following infection in utero. Multiple studies have demonstrated the transmission of Toxoplasma gondii by blood transfusion. The objective of this review was to comprehensively assess the seroprevalence rate of Toxoplasma in blood donors from a worldwide perspective. Seven electronic databases (PubMed, Science Direct, Web of Science, Scopus, Cochrane, Ovid, and Google Scholar) were searched using medical subject headings terms. A total of 43 records met the inclusion criteria in which 20,964 donors were tested during the period from January 1980 to June 2015. The overall weighted prevalence of exposure to toxoplasmosis in blood donors was 33% (95% confidence interval [CI], 28%-39%). The seroprevalences of immunoglobulin (Ig)M and both IgG and IgM antibodies were 1.8% (95% CI, 1.1%-2.4%) and 1.1% (95% CI, 0.3%-1.8%), respectively. The highest and the lowest seroprevalences of toxoplasmosis were observed in Africa (46%; 95% CI, 14%-78%) and in Asia (29%; 95% CI, 23%-35%), respectively. Brazil (75%) and Ethiopia (73%) were identified as countries with high seroprevalence. Because positive serology does not imply infectiousness and because seroprevalence is high in some nations, a positive serology test result alone cannot be used as an effective method for donor screening. Future research for methods to prevent transfusion-transmitted toxoplasmosis may derive benefit from studies conducted in areas of high endemicity.

Isolation and Genotyping of Toxoplasma gondii Strains in Ovine Aborted Fetuses in Khorasan Razavi Province, Iran

Toxoplasmosis is an important zoonotic disease that can cause abortion in humans and animals. The aim of this study was isolation and subsequent genotyping of Toxoplasma gondii isolates in ovine aborted fetuses. During 2012-2013, 39 ovine aborted fetuses were collected from sheep flocks in Khorasan Razavi Province, Iran. The brain samples were screened for detection of the parasite DNA by nested PCR. The positive brain samples were bioassayed in Webster Swiss mice. The serum samples of mice were examined for T. gondii antibodies by IFAT at 6 weeks post inoculation, and T. gondii cysts were searched in brain tissue samples of seropositive mice. The positive samples were genotyped by using a PCR-RLFP method. Subsequently, GRA6 sequences of isolates were analyzed using a phylogenetic method. The results revealed that T. gondii DNA was detected in 54% (20/37, 95% CI 38.4-69.0%) brain samples of ovine aborted fetuses. In bioassay of mice, only 2 samples were virulent and the mice were killed at 30 days post inoculation, while the others were non-virulent to mice. The size of cysts ranged 7-22 µm. Complete genotyping data for GRA6 locus were observed in 5 of the 20 samples. PCR-RLFP results and phylogenetic analysis revealed that all of the isolated samples were closely related to type I. For the first time, we could genotype and report T. gondii isolates from ovine aborted fetuses in Khorasan Razavi Province, Iran. The results indicate that the T. gondii isolates are genetically related to type I, although most of them were non-virulent for mice.

Review on the identification and role of Toxoplasma gondii antigenic epitopes

Toxoplasma gondii is an obligate intracellular protozoan parasite with a broad range of hosts, and it causes severe toxoplasmasis in both humans and animals. It is well known that the progression and severity of a disease depend on the immunological status of the host. Immunological studies on antigens indicate that antigens do not exert their functions through the entire protein molecule, but instead, specific epitopes are responsible for the immune response. Protein antigens not only contain epitope structures used by B, T, cytotoxic T lymphocyte (CTL), and NK cells to mediate immunological responses but can also contain structures that are unfavorable for protective immunity. Therefore, the study of antigenic epitopes from T. gondii has not only enhanced our understanding of the structure and function of antigens, the reactions between antigens and antibodies, and many other aspects of immunology but it also plays a significant role in the development of new diagnostic reagents and vaccines. In this review, we summarized the immune mechanisms induced by antigen epitopes and the latest advances in identifying T. gondii antigen epitopes. Particular attention was paid to the potential clinical usefulness of epitopes in this context. Through a critical analysis of the current state of knowledge, we elucidated the latest data concerning the biological effects of epitopes and the immune results aimed at the development of future epitope-based applications, such as vaccines and diagnostic reagents.

Goats reinfected with Toxoplasma gondii: loss of viable prolificacy and gross revenue

ABSTRACTWe determined the reproductive parameters and clinical disorders in pregnant goats infected and reinfected with Toxoplasma gondii, and posteriorly the loss of gross revenue due to congenital toxoplasmosis was estimated. Of the 25 non-pregnant females negative for T. gondii, 20 were orally inoculated (ME 49 strain) and of these, 15 pregnant females chronically infected were orally reinoculated (VEG strain) with T. gondii oocysts. Five groups were formed (n=5): GI, GII and GIII (reinoculations at 40, 80 and 120 days of gestation, respectively), GIV (inoculation) and GV (no inoculation). Clinical and serological exams were performed on days 0 (prior to inoculation), 3, 6 9, 15 and 21 and every 7 days post-inoculation. Exams were also performed on day 3 and every 7 days post-reinoculation. Reproductive management was performed on all females and initiated when the females infected displayed IgG titers IFAT<1,024. From the average prolificacy indexes of each experimental group were estimated: total production of kilograms of live weight (total kg LW) of goats for slaughter, gross revenue and loss of gross revenue in U.S. dollars (US$), designed for a herd of 1,000 matrices. The unviable prolificacy indexes were 0.8 (GI), 1.2 (GII) and 0.2 (GIII). Clinical disorders affected 57.1% (GI), 75.0% (GII) and 16.7% (GIII) of the offspring of goats reinfected with T. gondii. Congenital toxoplasmosis in goats reinfected resulted in the loss of 26.5% of gross revenues, being GI (US$ 10,577.60 or 57.1%) and GII (US$ 12,693.12 or 60%) holders of the highest values and percentages of economic losses. It was found that congenital toxoplasmosis reinfection cause clinical disorders in goats chronically infected with T. gondii and their offspring with birth of unviable animals and loss of gross revenue, at different stages of pregnancy (40, 80 and 120 days of gestation), being in the initial and intermediate stages of pregnancy the largest estimates of these losses.

A long-lasting protective immunity against chronic toxoplasmosis in mice induced by recombinant rhoptry proteins encapsulated in poly (lactide-co-glycolide) microparticles

Toxoplasma gondii infection in humans and animals is a worldwide zoonosis. Prevention and control of toxoplasmosis based on vaccination is one of the promising strategies. In the present study, recombinant T. gondii rhoptry proteins 38 and 18 (TgROP38 and TgROP18) were encapsulated into poly (lactide-co-glycolide) (PLG) (1:1), respectively, to obtain the stable water-in-oil-in-water double emulsion. Female Kunming mice were then immunized with the protein vaccines twice at a 2-week interval. Eight weeks after the second immunization, 10 mice from each group were challenged with T. gondii PRU strain (genotype II). The entrapment rates of PLG-rROP38 and PLG-rROP18 ranged from 65.5 to 77.7% and 58.1 to 72.3%, respectively. Immunization of mice with rROP38 and rROP18 proteins encapsulated into PLG microparticles elicited strongly humoral and cell-mediated responses against T. gondii, associated with relatively high levels of total IgG, IgG2a isotype, and IFN-γ, as well as the mixed Th1/Th2 immunity responses. Immunization with various protein vaccines induced significant reduction of the brain cysts after chronic infection with the T. gondii PRU strain, and the most effective protection was achieved in the PLG-rROP38-rROP18-immunized mice, with a cyst reduction of 81.3%. The findings of the present study indicated that recombinant rhoptry antigens encapsulated in PLG could maintain the protein immunogenicity in an extended period and elicit effective protection against chronic T. gondii infection, which has implications for the development of long-lasting vaccines against chronic toxoplasmosis in animals.

Herd-level prevalence and associated risk factors for Toxoplasma gondii, Neospora caninum, Chlamydia abortus and bovine viral diarrhoea virus in commercial dairy and beef cattle in eastern, northern and northeastern China

Although the seroprevalence of Toxoplasma gondii, Neospora caninum, Chlamydia abortus and bovine viral diarrhea virus infection in cattle have been reported in some areas in China, most of them were conducted with small number of cattle samples and very limited districts and neglected the assessment of herd management factors associated with herd-level prevalence of these pathogen infections. Thus, from September 2013 to December 2014, a large-scale seroprevalence study was conducted to determine the animal-level and herd-level seroprevalence and identify herd-level risk factors associated with these pathogen infections in 4487 cattle from 134 herds in five provinces (Heilongjiang, Jilin, Liaoning, Shandong, Hebei) and Inner Mongolia Autonomous Region of China. At animal level, the true prevalence of antibodies against T. gondii, N. caninum, C. abortus and bovine viral diarrhoea virus (BVDV) was 10.48, 17.14, 11.92 and 50.10%, respectively. At herd level, the true prevalence of antibodies against T. gondii, N. caninum, C. abortus and BVDV was 27.16, 29.10, 37.31 and 40.30%, respectively. Multivariate analysis of these characteristics showed that source of water and presence of felids were significantly associated with T. gondii infection in the studied cattle herds. Source of water was significantly associated with N. caninum infection in the studied cattle herds. While herd size and management system were significantly associated with BVDV infection in the studied cattle herds, this is the first report of herd-level prevalence and associated risk factors of T. gondii, N. caninum, C. abortus and BVDV infection in cattle in China.