Prevalence of Toxoplasma gondii DNA in Processed Pork Meat.

Toxoplasma gondii infection may be attributed to the ingestion of pork meat and contaminated water. In southern Brazil, the prevalence of blindness caused by T. gondii is the highest in the world. Our purpose is to determine the frequency of T. gondii DNA in commercial fresh sausage and cured salami samples from Rio Grande do Sul state, south of Brazil. A total of 118 samples (sausage and salami) from 8 different producers were collected and DNA was extracted. Real-time polymerase chain reaction (qPCR) technique was performed to detect T. gondii DNA using B1 marker. The frequency of T. gondii DNA among the total number of samples (sausage and salami) was 39% (46/118). Among these, a higher frequency of positivity was observed in the sausage samples (47.5%) when compared with the salami samples (17%). However, the mean parasite concentration was significantly higher in the salami samples. The prevalence of T. gondii DNA in fresh sausage and cured salami may indicate that infected pigs may be an important source of infections and a public health hazard to be considered.

Toxoplasmosis in camels (Camelus dromedarius) of Borana zone, Oromia region, Ethiopia: seroprevalence and risk factors.

Toxoplasmosis is one of the most prevalent parasitic infections of medical and veterinary importance. A cross-sectional study was conducted from November 2013 to January 2014 to estimate the seroprevalence of Toxoplasma gondii infection in camels from four districts of Borana zone, Southern Oromia, Ethiopia. In addition, a questionnaire survey was administered to 124 pastoralists to identify possible risk factors and to assess the awareness level of pastoral communities about toxoplasmosis. A total of 396 serum samples were examined for anti-Toxoplasma IgG antibodies using the direct agglutination test (DAT). Fisher's exact test and logistic regression were used for data analysis. An overall seroprevalence of 8.33 % (95 % confidence interval [CI] 5.60 %, 11.07 %) at animal-level and 37.5 % (95 % CI: 20.1 %, 57.4 %) at herd-level was found. The seroprevalence was significantly high in Moyale district (23.07 %) followed by Yabello (7.20 %), Dirre (3.77 %), and Arero (0.0 %) districts (P < 0.001). Multivariable logistic regression analysis revealed that the likelihood of acquiring T. gondii infection was significantly higher in camels of Moyale district (adjusted OR = 5.89, 95 % CI 2.15, 16.12; P = 0.001) than Dirre district, in camels of >8 years old (adjusted odds ratio [OR] = 4.95, 95 % CI 1.68, 14.55; P = 0.004) than camels of ≤4 years old. There was no significant association between herd-level seroprevalence of T. gondii infection and abortion history, herd size, and presence of domestic cats and wild felids (P > 0.05). The majority of interviewees were uneducated (82.25 %), and all had no knowledge of toxoplasmosis. All camel herders drink raw camel milk but consume cooked meat (90.32 %). Of the interviewees, 93.06 % are aware about soil-eating habit of camels and provide salt supplement for their camels. Majority of the respondents practice improper disposal of aborted materials (throw along the way) (88.70 %), and 73 % of the study participants do not wash their hands after handling aborted fetus. The results of the present study confirm relatively lower prevalence of T. gondii infection in camels reared in Borana zone. Age and study district are significant predictors of T. gondii seropositivity. The vast majorities of interviewed pastoralists were uneducated and practice poor biosecurity measures to prevent diseases. Education of pastoralists about biosecurity measures to prevent toxoplasmosis and further studies are warranted to unravel the economic and public health consequences of T. gondii infection.

Seroprevalence and risk factors of Toxoplasma gondii in Tibetan Sheep in Gansu province, Northwestern China.

BACKGROUND: Toxoplasma gondii, a protozoan parasite, infects almost all warm-blooded animals and humans. Limited information is available about T. gondii infection in Tibetan Sheep in Gansu province, northwestern China. In the present study, we estimated the seroprevalence and risk factors of T. gondii infection in this region of China. RESULTS: A total of 1732 Tibetan Sheep were included from Tianzhu and Maqu in Gansu province. Antibodies to T. gondii were examined by modified agglutination test (MAT), and 352 (20.3%) out of 1732 Tibetan sheep were found positive. Multivariate logistic regression analysis was used to analyze the risk factors associated with seroprevalence, the results showed that age, gender, and numbers of past pregnancies were not the significant risk factors. However, Tibetan sheep in Maqu had a 1.64 times (odds ratio [OR] =1.637, 95% CI =1.291-2.075, P < 0.001) higher seroprevalence compared to Tianzhu, and the seropositivity in summer were 1.61 times (OR =1.608, 95% CI =1.122-2.303, P = 0.010) higher compared to Tibetan sheep in winter, followed by 1.42 times (OR =1.419, 95% CI =1.002-2.011, P = 0.049) in spring. Thus, season and location were considered as risk factors associated with T. gondii infection in this study. CONCLUSIONS: This is the first report of T. gondii seroprevalence in Tibetan sheep in Gansu province, which enriches the epidemiological data of T. gondii infection in Tibetan sheep in China. The results of this study indicate that Tibetan sheep in Gansu province are frequently exposed to T. gondii, posing a direct threat to the public health as well as to local sheep industry. These data is useful to strengthen future prevention and control of T. gondii infection in Tibetan sheep in this region.

Seroprevalence and risk factors for Toxoplasma gondii in sheep in Grosseto district, Tuscany, Italy.

BACKGROUND: Serum samples from 630 milk sheep, in 33 dairy flocks representative of the southern area of the Tuscany region, were tested for the presence of antibodies to Toxoplasma gondii using an indirect immunofluorescence antibody test (IFAT). Questionnaires exploring the management system were completed by the veterinarian in charge of the flocks. RESULTS: At least one seropositive animal was found in 32 of the 33 flocks tested (97.0%; 95% CI: 84.2%, 99.9%). In the positive flocks, median seroprevalence was 29.4% (interquartile range: 15.9%-46.1%). Overall animal-level seroprevalence, adjusted for sampling weights and test sensitivity and specificity, was 33.3% (95% CI: 24.8%, 42.7%). In a multivariable negative binomial regression model the number of seropositive animals in a flock decreased with increasing flock size (for >400 vs. <300 animals: count ratio (CR) = 0.62; 95% CI: 0.41, 0.95; P = 0.028) and was greater on farms where stray cats had access to animals' water (CR = 1.54; 95% CI: 1.05, 2.26; P = 0.027). CONCLUSIONS: Small flock size and access of cats to water are potential risk factors for Toxoplasma infection in sheep in the Grosseto district in Tuscany, Italy. Sheep could be an important source of T. gondii infection in humans, since we estimate that between 25% and 43% of sheep in the district were seropositive. Toxoplasmosis is also likely to be an important cause of abortion in sheep in the district. Control and prophylactic measures must be adopted to improve the rearing system and the implementation of health promoting programmes in a joint effort between sheep farmers, farmers' associations and veterinarians to inform about the means of transmission of the infection and for a better understanding of the disease.

Toxoplasma gondii in cats: fecal stages identified as coccidian oocysts.

Isospora-type oocysts were excreted by cats following the ingestion of Toxoplasma fromn infected mice. Oocysts appeared 3 to 5 days after cyst. were ingested and 8 to 10 days after trophozoites were ingested, and also 21 to 24 days after the administration of infective fecal suspensions from cats. A close quanititative and biologic correlation between oocysts and Toxoplasma infectivity of the feces was observed which could not be separated by density gradient centrifugation and filtration methods. Toxoplasma is an intestinal coccidian of cats which is fecally spread. It has evolved to multiply in brain and muscle and in other species, making it possible for carnivorism to become another means of transmission.

First report on seroprevalence and risk factors of Toxoplasma gondii infection in sheep and goats in North Lebanon.

INTRODUCTION: Toxoplasmosis is of dual importance in both public and veterinary health due to the respective risk of transplacental transmission in primo-infected pregnant women and economic losses caused by abortions in mammals. One of the main routes of Toxoplasma gondii transmission to humans is the consumption of raw or undercooked meats containing parasitic cysts. Here, we performed the first epidemiological study to determine the seroprevalence and the risk factors of toxoplasmosis in livestock in Lebanon. METHODOLOGY: Using a modified agglutination test with a cut-off of 1:40, we tested the positivity rate of Immunoglobulin G antibodies in the sera of 100 sheep and 80 goats collected from 18 different livestock farms located in North Lebanon between March and June 2018. RESULTS: Anti-Toxoplasma gondii IgG antibodies were detected in 42% of sheep and 34% of goats. Adults (> 1 year) were significantly more infected by T. gondii than the lambs (< 1 year) in both species (p < 0.05). CONCLUSIONS: These findings indicated that food animals are highly exposed to T. gondii in Lebanon and could be potentially a major risk factor of T. gondii infection to humans. Consequently, national prophylactic strategies should be implemented to control and to prevent T. gondii transmission between animals and humans.

Toxoplasma gondii seroprevalence in extensively farmed wild boars (Sus scrofa) in Denmark.

Toxoplasma gondii is a zoonotic parasite of worldwide importance. In this study, we estimated T. gondii seroprevalence in extensively farmed wild boars in Denmark, where little is known about T. gondii in animal hosts. Our study focused on wild boars because they are considered good indicator species for the presence of T. gondii, and wild boar meat is used for human consumption. Serum samples from 101 wild boars collected in 2016-2018 from five different locations from the continental part of Denmark, Jutland, were screened for anti-T. gondii antibodies. The samples were analysed using a commercial indirect enzyme-linked immunosorbent assay (ELISA). Samples from 28 (27.7%) of the 101 wild boars tested positive with the ELISA. The odds for a wild boar to test seropositive were higher if it was sampled during the hunting season 2017-2018 than during 2016-2017 and if it was reported to be at least 1 year old than if it was younger (logistic regression model with the two variables: odds ratios 17.5 and 3.9, respectively). A substantial proportion of the investigated extensively farmed wild boars had been exposed to T. gondii. Moreover, the parasite appeared widespread, at least in the continental part of Denmark, Jutland, as seropositive wild boars were found from all five sampled locations. Assuming seropositivity indicates hosting viable parasites, consumption of undercooked wild boar meat from Denmark is a potential source of T. gondii infections to other hosts, including humans.

A serological study on the prevalence of Toxoplasma gondii in sheep of Lithuania.

In the present study the seroprevalence of the protozoan parasite Toxoplasma gondii infection in sheep was investigated in 6 regions of Lithuania. Blood samples were taken from 354 sheep and were tested using commercial ELISA method. The total seroprevalence of Toxoplasma gondii infection in sheep was 42.1%. Significant differences in seroprevalence were observed between age groups (P < or = 0.05). The results of this investigation suggest that the Toxoplasma gondii parasite is widely spread, and can be one of reasons of sheep abortion in Lithuania.

Experimental Toxoplasmosis in Japanese Quails (Coturnix coturnix japonica).

OBJECTIVE: In this study, forming of experimental toxoplasmosis in quails; clinical, pathological, and serological determination of tissue lesions and bioassay techniques, which were aimed to compare them and determine pathogenesis. METHODS: A total of 120 one-year-old female quails (Coturnix coturnix japonica) were divided into oral infection, parenteral infection, and control groups. The oral group was infected with 0.5 ml inoculum suspension containing 106 tachyzoites of Toxoplasma gondii, whereas the control group was administered 0.5 ml of saline. The parenteral group was further divided into the following four subgroups: intraperitoneal, intramuscular, intravenous, and cloacal. The quails of the parenteral group were also divided into two groups and one by control group within itself for the 105 and 104 doses of the tachyzoite inoculums. RESULTS: Because of acute toxoplasmosis, death occurred in a quail that as intramuscularly infected with 105 tachyzoites; the quail exhibited neurological clinical symptoms such as torticollis, ataxia, and tremor. In histopathologic examination, T. gondii tissue cysts were detected in infected quails that were intramuscularly infected with 105 tachyzoites. Mouse trials were conducted using tissues of seropositive quails and isolated from peritoneal fluids infected mice. By Sabin-Feldman dye test and indirect hemagglutination test, seropositivity was observed in quails infected with 105 and 104 tachyzoites. CONCLUSION: Similar studies and subclinical cases, which may overlooked was concluded for diagnosis of toxoplasmosis with useful bioassay applications and serological tests.

Risk factors associated with Toxoplasma gondii infection in free-range chickens in the semiarid region of Brazil.

This study aimed to investigate the frequency of anti-Toxoplasma gondii antibodies in serum from 629 chickens on 39 family farms in seven municipalities in the semiarid region, Pernambuco, Brazil, and to identify risk factors associated with T. gondii infection. The risk factors were studied in 421 samples from 29 farms. Anti-T. gondii antibodies were investigated by indirect fluorescent antibody test with a 1:16 cutoff. The frequency of positive chickens was 27.9% (176/629) and 94.8% of the farms studied had chickens infected by T. gondii. Multivariate analysis showed variables significantly associated with anti-T. gondii antibodies in serum: slaughter of animals on the farm, reproductive disorders in sheep, consumption of fetal adnexa and placentas by chickens, presence of sheep in the property and birth of sheep the property. The results suggest that there is a complex relationship between general management practices for different animal species raised on the same farm and the prevalence of T. gondii infection in chickens. In addition, the results draw attention to the risk of human infection by T. gondii via consumption of infected chicken meat, because the farming conditions and the low human development indices observed in the region studied result in inappropriate meat preparation practices.

Antemortem diagnosis and treatment of toxoplasmosis in two cats on cyclosporin therapy.

Clinical toxoplasmosis was diagnosed antemortem in two cats being treated with therapeutic doses of cyclosporin. The diagnosis was made by detecting tachyzoites on cytological examination of bronchoalveolar lavage fluid from one case and pleural effusion from the other. Despite early diagnosis and aggressive treatment in both cases, only one cat survived. Reactivation of latent Toxoplasma gondii infection secondary to cyclosporin-induced immunosuppression was considered likely in both cases. The presence of respiratory signs in cats treated with cyclosporin should alert clinicians to the possibility of clinical toxoplasmosis. Consideration should be given to determining the serostatus of cats to T gondii prior to use of drugs which are potent inhibitors of cell mediated immunity, such as cyclosporin. Two cases of feline toxoplasmosis are presented.

Risk factors for Toxoplasma gondii infection in sheep and cattle from Fernando de Noronha Island, Brazil.

Toxoplasmosis is a zoonotic disease of global distribution that affects all warm-blooded animals. The purpose of this investigation was to determine the prevalence of T. gondii infection and identify the risk factors associated with its occurrence in domestic ruminants raised on the island of Fernando de Noronha, Brazil, and to confirm that cattle and sheep raised in Fernando de Noronha Island present statistically different T. gondii prevalence rates. Serum samples were collected from sheep (n=240) and cattle (n=140) for the detection of antibodies by indirect immunofluorescence. Samples were collected from all the animals on all the farms. Risk factors were analyzed by univariate analysis and logistic regression. The prevalence rate of positive sheep was 85.0% while that of cattle was 10.7%. A multivariate analysis revealed that the site of contact of sheep with felines was a risk factor. For cattle, the risk factors identified in this study were: extensive farming system, water source, more than three cats per farm, and the presence of rats in feed storage locations. The findings revealed a significant difference in the prevalence rates in sheep and cattle raised in this insular environment.

Acquired retinochoroiditis in hamsters inoculated with ME 49 strain Toxoplasma.

PURPOSE: These studies were undertaken to establish an animal model for use in studies of ocular toxoplasmosis. An animal model is needed to examine the development, progression, and resolution of ocular Toxoplasma infections and to study the effects on the disease of currently used and experimental therapies. METHODS: Cysts of the ME 49 strain of Toxoplasma gondii were injected intraperitoneally into each of 60 golden hamsters. The hamsters' eyes were examined before inoculation and at intervals after inoculation, and fundus photographs were taken. Histologic sections were analyzed and photographed to document the ocular effects of the infection. RESULTS: Retinochoroiditis was found in both eyes of all hamsters within 2 to 3 weeks of inoculation. The disease resolved spontaneously without treatment and was quiescent in most cases at 12 weeks after inoculation. The animals remained in good general health, and those tested had high antibody titers to Toxoplasma (1:256 to 1:32,000) at 6 months after the infection. The discovery of cysts and lesions in the retina confirmed the diagnosis. CONCLUSIONS: Although the lesions were not identical to those of human disease, this animal model of ocular toxoplasmosis offers several advantages: reproducibility, short incubation time, spontaneous resolution without treatment, consistent production of cysts, and ease of inoculation intraperitoneally without intraocular injection.

Involvement of apoptosis and interferon-gamma in murine toxoplasmosis.

PURPOSE: A murine toxoplasmosis model has been developed that results in central nervous system (CNS) and ocular inflammation characterized by encephalitis with numerous brain tissue cysts and milder inflammation with rare tissue cysts in the eye after 4 weeks of Toxoplasma gondii infection. In this model IFN gamma and inducible nitric oxide (iNO) are protective against T. gondii infection. In this study, the role of apoptosis in the pathogenesis of toxoplasmosis was investigated. METHODS: C57BL/6 (wild-type mice), B6MRL/lpr, and B6MRL/gld (defective Fas or FasL expression, respectively) mice were infected intraperitoneally with 20 to 30 tissue cysts of the ME-49 strain of T. gondii. Mice were killed at days 0, 14, or 28 after infection. The eyes and brains were harvested for histologic, immunohistochemical, and molecular studies. Analysis included immunostaining for Fas, FasL, Bcl-2, and Bax; in situ apoptosis detection (TUNEL assay); RT-PCR amplification for IFN gamma; and measurement of ocular nitrite levels. The control mice were naïve mice of each strain that received no inoculation or injection. RESULTS: Wild-type mice appeared to constitutively express apoptotic molecules at higher levels in the eye than in the brain. Consequently, during T. gondii infection, apoptosis was greater in the eyes than in the brain. Untreated naïve lpr and gld mice showed no expression of Fas and FasL, respectively. After infection, a slightly higher number of tissue cysts (lpr, 11.8 +/- 2.4; gld, 10.3 +/- 3.4) were found in the brains of the mutants than in the control animals (8.8 +/- 2.9). However, no significant differences between the number of apoptotic cells, inflammatory scores, or number of tissue cysts were noted in the eyes. IFN gamma mRNA in control mice was detected at day 28 after infection, whereas in both mutants, mRNA production occurred earlier, at day 14. Ocular nitrite levels were higher in lpr and gld mice than in wild-type mice. CONCLUSIONS: No significant difference in the degree of ocular inflammation and apoptosis was detected between the wild-type and Fas or FasL mutant mice. However, there was an earlier and subjectively greater expression of IFN gamma in the brain and eye and a higher level of nitrite in the ocular tissue of mutant strains than in the wild type. Multiple factors are likely to be involved in the pathogenesis of ocular toxoplasmosis.

Increased susceptibility to Toxoplasma gondii infection in SAG-1 transgenic mice.

SAG-1, one of the major surface proteins of Toxoplasma gondii, has been reported to play an important role in immune and pathogenic mechanisms of the parasites but its exact function is still unclear. We investigated the time courses of T. gondii infection in B6C3F1 transgenic mice carrying the SAG-1 gene. SAG-1 transgenic mice were infected intraperitoneally with a high virulent RH strain or a low virulent Beverley strain of T. gondii. When infected with RH strain tachyzoites, no significant differences in time courses of survivals between SAG-1 transgenic and wild-type mice were observed. Both groups succumbed to an acute infection within 8 days after infection. However, a lower survival rate (20%) was observed in SAG-1 transgenic mice than in wild-type (80%), when infected with Beverley strain cysts. This result indicates that SAG-1 transgenic mice are more susceptible to T. gondii infection as compared with their wild-type counterpart. ELISA using recombinant SAG-1 protein indicates that SAG-1 transgenic mice do not produce antibodies to the SAG-1 molecule. These findings may provide a critical tool for analysing the molecular mechanisms of pathogenesis and host immune responses during toxoplasmosis.

Toxoplasmosis: comparative species susceptibility and host immune response.

The protozoan parasite Toxoplasma gondii is capable of infecting all warm blooded animals; however, the consequences of infection are very variable between different species of animal. Marsupials and New World monkeys, which have evolved largely separately from the cat, the definitive host of the parasite, are among the most vulnerable species where infection with T. gondii can prove fatal. In more resistant species such as humans and sheep, infection is generally unapparent, provoking only mild symptoms; thereafter the host remains infected for life. However, when the immune system is compromised, such as in the immunologically immature fetus, infection with the parasite can have very serious consequences. Much of the work examining host immune responses has been done using experimentally infected mice. While there are many advantages in using this experimental model, care should be taken in extrapolating results from mice to other species. Mice are extremely vulnerable to the consequences of infection with T. gondii., and their use to further our understanding of congenital toxoplasmosis may not be ideal, as fetal infection can occur in successive pregnancies. This is not the case in rats or sheep; they are more resistant to the disease and therefore may provide a more relevant model for human congenital toxoplasmosis. Studies of host immune responses have emphasised the importance of the cytokine interferon gamma (IFN gamma) in resistance to T. gondii. The efficiency of induction of this cytokine may be critical for determining the outcome of the host-parasite relationship.

Toxoplasma gondii infection in sheep and cattle.

Toxoplasma gondii is a protozoan parasite that can infect all warm-blooded animals. Sheep and cattle show different susceptibilities to T. gondii infection. Primary infection in pregnant sheep can result in abortion or the birth of weak lambs but they are then protected against further challenge by the development of an effective immunity. Cattle on the other hand can be readily infected, but abortion or perinatal mortality have not been recorded. The evidence suggests that cattle develop a more effective immune response to T. gondii infection than sheep. Potential mechanisms to explain these differences are discussed in this paper.

Pathogeny and immunological control of toxoplasmosis.

1. Toxoplasma gondii is a ubiquitous, obligate intracellular parasite of worldwide distribution. In humans, the parasite exists in two forms: the tachyzoite is the rapidly multiplying stage of the parasite which actively invades host cells and represents the principal pathogenic form at the acute phase of the disease; the bradyzoite is the form which multiplies slowly in host cells, resulting in the formation of cysts which persist in tissues. Several antigenic components have been identified, some of which are characteristic for each parasitic stage; particularly, in tachyzoites, the 30 kDa membrane protein represents up to 5% of the total protein content. 2. Toxoplasma infection in humans is usually asymptomatic because of effective immunity involving antibodies, T cells and cytokines. Activated macrophages, CD4 and CD8 lymphocytes and cytokines, such IFN gamma, play a major role in the control of acute infection and the maintenance of infection at the chronic stage. The alteration of immune functions, as observed in congenitally infected children and in HIV-infected patients, may induce the recrudescence of previously latent toxoplasmosis, in relation to disruption of the cyst form of the parasite. The resulting reactivation is responsible for life-threatening infections which are frequently manifested as toxoplasmic encephalitis. 3. In this review, the parasite and immunological factors participating in the pathogenesis of the lesions associated with acute, chronic and reactivated toxoplasmosis are presented.

Bayesian modeling of animal- and herd-level prevalences.

We reviewed Bayesian approaches for animal-level and herd-level prevalence estimation based on cross-sectional sampling designs and demonstrated fitting of these models using the WinBUGS software. We considered estimation of infection prevalence based on use of a single diagnostic test applied to a single herd with binomial and hypergeometric sampling. We then considered multiple herds under binomial sampling with the primary goal of estimating the prevalence distribution and the proportion of infected herds. A new model is presented that can be used to estimate the herd-level prevalence in a region, including the posterior probability that all herds are non-infected. Using this model, inferences for the distribution of prevalences, mean prevalence in the region, and predicted prevalence of herds in the region (including the predicted probability of zero prevalence) are also available. In the models presented, both animal- and herd-level prevalences are modeled as mixture distributions to allow for zero infection prevalences. (If mixture models for the prevalences were not used, prevalence estimates might be artificially inflated, especially in herds and regions with low or zero prevalence.) Finally, we considered estimation of animal-level prevalence based on pooled samples.