Seroprevalence of T. gondii in sheep from Marrakech, Morocco

Toxoplasma gondii is a ubiquitous intracellular protozoan parasite transmitted by food. Concerning this parasite, there are few studies done in Morocco. In this study, 261 sera from sheep intended for consumption in Marrakech were subjected to the Toxoplasma ELISA based serology test for the detection of anti-T. gondii specific IgG confirming a past infection. Of the total tested 72 (27.6%) sera were positive for IgG. This result shows that the seroprevalence approaches the world average and is similar to what is found in other cities of Morocco. This has prompted us to investigate other animal species in the region in order to evaluate the degree of contamination by this parasite as well as the potential risk incurred on consumption of their meat.     

Survey to determine the seroprevalence of Toxoplasma gondii infection in British sheep flocks

A serological survey of Toxoplasma gondii infection in adult breeding sheep in Great Britain was conducted using surplus sera taken during a seroprevalence study of Brucella melitensis in 2009. Of the 3539 sera collected from 227 flocks, 2619 (74 per cent) were found to be positive for T gondii specific antibody when tested using latex agglutination. Multilevel logistic modelling suggested that the likelihood of infection increased with age and this effect appeared to be amplified in animals vaccinated against T gondii. The model also indicated that the odds of sheep being seropositive were increased on premises where cattle were also kept. These results suggest a high level of Toxoplasma infection in breeding sheep in Great Britain and provide further evidence to suggest that postnatal infection is more common than congenital infection in sheep.     

我国部分地区牛羊弓形虫血清流行病学调查

为了解我国牛羊弓形虫病流行情况,应用间接血凝试验（IHA）对河南、山东、山西、内蒙古、云南、贵州6省区151份牛血清、50份奶样、490份羊血清进行了弓形虫病血清流行病学调查。结果显示：151份被检牛血清和50份牛奶样品,弓形虫抗体均为阴性。490份羊血清弓形虫抗体总阳性率5.71％,其中母羊、公羊血清阳性率分别为4.03％和9.79％;山羊、绵羊、杂交羊血清阳性率分别为6.58％、4.81％和5.13％;阳性率最高的为公山羊（13.2％）,最低的为母绵羊（2.96％）。28份阳性羊血清中,75％的抗体滴度为1：64,25％的抗体滴度为1：256。1岁后的羊,随年龄增长,血清阳性率升高。     

Increased Toxoplasma gondii positivity relative to age in 125 Scottish sheep flocks; evidence of frequent acquired infection

Toxoplasma gondii seroprevalence was determined in 3333 sheep sera from 125 distinct sheep flocks in Scotland, with the majority of flocks being represented by 27 samples, which were collected between July 2006 and August 2008. The selected farms give a representative sample of 14 400 sheep holdings identified in the Scottish Government census data from 2004. Overall T. gondii seroprevalence, at individual sheep level, was determined to be 56.6%; each flock tested, had at least a single positive animal and in four flocks all ewes tested positive. The seroprevalence of sheep increased from 37.7% in one year old stock to 73.8% in ewes that were older than six years, showing that acquired infections during the life of the animals is frequent and that environmental contamination by T. gondii oocysts must be significant. The median within-flock seroprevalence varied significantly across Scotland, with the lowest seroprevalence of 42.3% in the South and the highest seroprevalence of 69.2% in the far North of Scotland and the Scottish Islands, while the central part of Scotland had a seroprevalence of 57.7%. This distribution disequilibrium may be due to the spread and survival of oocysts on pasture and lambing areas. A questionnaire accompanying sampling of flocks identified farms that used Toxovax^®, a commercial vaccine that protects sheep from abortion due to T. gondii infection. Only 24.7% of farmers used the vaccine and the vaccine did not significantly affect the within flock seroprevalence for T. gondii. The implications for food safety and human infection are discussed.     

Toxoplasma gondii seroprevalence in domestic animals and humans in Mymensingh District, Bangladesh

The seroprevalence of Toxoplasma gondii was examined in adult women and domestic animals used for meat products from the Mymensingh District, Bangladesh. Cattle, goats and sheep showed a high seroprevalence (12, 32 and 40%, respectively), while the sera from all fifteen women examined in the same area were seronegative. Considering that primary infection in women during pregnancy can cause abortion and congenital defects, accidental ingestion of T. gondii infected meat products from domestic animals represents a risk factor for adult women living in the same area.     

屠宰羊弓形虫感染情况调查

为了保障羊肉制品的生物安全,对屠宰羊进行弓形虫感染情况调查以及对羊肉进行弓形虫检测。采用间接血凝试验,对677份屠宰羊的血清进行了弓形虫抗体检测。结果显示,弓形虫抗体阳性有47份,阳性率为6.9%。     

内蒙古部分地区放牧牛羊弓形虫血清学调查

[目的]了解内蒙古部分地区放牧牛羊弓形虫病感染情况。[方法]采用间接血凝试验(IHA)对阿拉善盟及呼伦贝尔市随机采集的286份放牧牛羊血清样本进行弓形虫抗体检测。[结果]绵羊血清弓形虫抗体总阳性率为1.68%,其中,阿拉善盟阳性率为4.84%,呼伦贝尔市阳性率为0.56%;经统计学分析,两个地区的绵羊血清弓形虫抗体阳性率差异不显著(P>0.05);牛血清弓形虫抗体总阳性率为0。[结论]内蒙古主要牧区放牧绵羊存在弓形虫感染,应引起足够的重视,并制定相应的弓形虫病防治措施。     

Toxoplasma gondii and ovine toxoplasmosis: new aspects of an old story

Ovine toxoplasmosis, caused by the intracellular protozoan parasite Toxoplasma gondii, was first described in 1954 and while the incidence of ovine infection is difficult to define, it has been reported that in the UK it is responsible for between 1 and 2% of neonatal losses per annum. Recent reports have suggested that sheep persistently infected with T. gondii may pass infection to the fetus in subsequent pregnancies more readily than previously thought. These data show a high proportion of both successful and failed pregnancies in sheep to be positive by PCR for T. gondii with a tendency for samples from certain genetic lines of Charollais sheep more likely to be positive than samples from other lines, suggesting that some sheep have a particular genetic susceptibility to T. gondii.     

Seroprevalence of Toxoplasma gondii and Neospora caninum in dairy goats from Romania

Little information is available about the seroprevalence of Toxoplasma gondii and Neospora caninum infections in goats in Romania and even in Europe. During 2007-2010, 735 serum samples were collected from dairy goats located in 4 historical regions (Cri?ana, Maramure?, Transylvania and Muntenia) of Romania. Sera were analyzed for T. gondii and N. caninum antibodies (IgG type) by enzyme-linked immunosorbent assay (ELISA) using two commercial kits (Chekit Toxotest Antibody ELISA and Chekit Neospora caninum Antibody ELISA; Idexx-Bommeli, Switzerland). Three hundred and eighty-eight out of 735 (52.8%) goats presented T. gondii antibodies and 12 out of 512 (2.3%) goats had N. caninum antibodies. The high seroprevalence of T. gondii suggests that infection with this parasite is common in dairy goats in Romania, and less common the infection with N. caninum. This is the first time that infection with N. caninum in goats has been reported in Romania and the first extended study on seroepidemiology of T. gondii.     

Toxoplasma gondii in Switzerland: a serosurvey based on meat juice analysis of slaughtered pigs, wild boar, sheep and cattle

Toxoplasmosis is one of the most important zoonotic diseases worldwide and is caused by the protozoan Toxoplasma gondii. Besides vertical infection during pregnancy, humans can get infected post-natally either by peroral uptake of sporulated Toxoplasma oocysts or by ingestion of tissue cysts upon consumption of raw or undercooked meat. The aim of this study was to approximate the risk of human infection via meat consumption by estimating the seroprevalence of T. gondii in slaughtered animals in Switzerland and to compare data with prevalences assessed 10 years ago. The study included pigs, cattle, sheep and wild boar of different age groups and housing conditions whenever possible and applicable. A P-30-ELISA was used to detect T. gondii-specific antibodies and to determine seroprevalences in meat juice of slaughtered animals. A total of 270 domestic pigs (120 adults, 50 finishing, 100 free-ranging animals), 150 wild boars, 250 sheep (150 adults, 100 lambs) and 406 cattle (47 calves, 129 heifers, 100 bulls, 130 adult cows) were tested. Seropositivity increased with the age of the assessed animals. Independent of the age-group, the overall seroprevalence was lowest in wild boars (6.7%), followed by pigs (23.3%), cattle (45.6%) and sheep (61.6%), respectively. Conventional fattening pigs and free-ranging pigs surprisingly had comparable seroprevalences (14.0% and 13.0%, respectively). Unlike in other European countries, where generally a decrease in the number of seropositive animals had been observed, we found that the prevalence of seropositive animals, when compared with that of 10 years ago, had increased for most species/age groups. Conclusively, the results demonstrated a high seroprevalence of T. gondii in animals slaughtered for meat production and revealed that increasing age of the animals is a more important risk factor than housing conditions in Switzerland.     

新疆阿勒泰地区绵羊弓形虫病的血清学调查

为了解新疆阿勒泰地区绵羊弓形虫病的感染情况以及感染弓形虫病与绵羊流产的关系,对阿勒泰地区6县1市的绵羊随机采集血清共565份,采用间接血凝试验进行了弓形虫感染的血清学检测。结果显示,阿勒泰地区各县(市)绵羊均有弓形虫感染,感染率高低不一,平均感染率为6.5%;在有流产史的绵羊中发现存在布鲁菌和弓形虫双重感染的情况,提示在预防和治疗绵羊流产时,除了要考虑布鲁菌感染的因素以外,还应考虑弓形虫感染这一因素。     

Seroepidemiology of infection with Toxoplasma gondii in waste pickers and waste workers in Durango, Mexico

Municipal waste is a potential source of infection for Toxoplasma gondii as it may contain contaminated meat with parasite tissue cysts and cat excrement with parasite oocysts. Therefore, we sought to determine the prevalence of T. gondii infection and associated characteristics in two populations exposed to municipal solid waste in Durango, Mexico. Ninety waste pickers and 83 waste workers of Durango City, Mexico were examined for T. gondii infection. They were tested for anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays. In addition, socio-demographic and behavioural characteristics from each participant were obtained. Nineteen (21.1%) of the 90 waste pickers and seven (8.4%) of the 83 waste workers were positive for anti-T. gondii IgG antibodies. The difference in prevalence among the groups was statistically significant (P =0.03). Waste pickers aged 31-50 years showed a significantly higher prevalence (40.9%) than waste workers of the same age group (2.9%, P < 0.001). Anti-T. gondii IgM antibodies were found in two (2.2%) of the waste pickers but in none of the waste workers. The seroprevalence of T. gondii was significantly higher in workers of the waste transfer station (25.0%) than in drivers or helpers of waste vehicles (2.5%) (P =0.03). Multivariate analysis showed that T. gondii infection was associated with consuming food found in the garbage [adjusted odds ratio (OR) = 4.4; 95% confidence interval (CI) 1.6-11.8] and with lack of education (adjusted OR = 3.2; 95% CI 1.1-8.8). From this study, we conclude: (i) waste pickers may represent a risk group for T. gondii infection; (ii) lack of education might be a contributing factor for T. gondii infection; (iii) the higher the exposure to garbage, the higher the seroprevalence of T. gondii infection; (iv) Eating food products from the garbage may represent an important route for T. gondii infection.     

Toxoplasma gondii infection in sheep from Haute-Vienne, France: seroprevalence and isolate genotyping by microsatellite analysis

Ingesting meat of free-range livestock, mainly sheep, is associated with human toxoplasmosis in European countries. Data on Toxoplasma gondii infection in French ovine livestock are relatively scarce. Sera from 164 lambs and 93 ewes slaughtered in Haute-Vienne district, France, were tested by a direct agglutination test. Antibodies to T. gondii were found in 36 (22.0%) lambs and in 61 (65.6%) ewes. In addition, to attempt parasite isolation for genotyping, hearts from 50 other ewes were obtained from a local slaughterhouse, and were screened by a direct agglutination test. T. gondii was isolated in 8 of 30 seropositive hearts bioassayed in mice. All isolates were type II by genetic characterization at five microsatellite loci (TUB2, TgM-A, W35, B17, B18). These results indicate that bovines slaughtered in France may be highly infected by T. gondii with a potential risk of parasite transmission to humans by consumption of undercooked meat. Multilocus microsatellite analysis shows the predominance of type II in sheep as previously described in humans.     

The occurrence of Toxoplasma gondii and Neospora caninum as regards meat hygiene

Toxoplasma gondii and Neospora caninum are phenotypically and phylogenetically closely related cyst-forming coccidia, both of which may cause abortion in livestock animals. T. gondii exhibits also zoonotic potential by causing diaplacental infections in the human fetus and harmful infections in immunosuppressed individuals. Humans get infected either by consuming inappropriately prepared cyst-containing meat or by ingesting oocysts originating from cat feces. Therefore, in order to assess infection risk we need to have knowledge on the prevalence of the parasite in consumable meat and thus slaughtered animals. So far, no data indicate any zoonotic potential for N. caninum. Due to its high economic impact in the bovine production in Switzerland, we included this parasite in the present study as well. The prevalence of both parasite species were investigated by PCR in muscle and brain samples of slaughtered bovines, sheep, pigs and horses. Comparatively, a serum sample from each animal was simultaneously tested serologically by a Toxoplasma-P30-ELISA and a Neospora-SA-ELISA. The prevalences determined by the T. gondii-PCR were the followings: adult cows 3%, young bulls 2%, young cows prior to gravidity 6%, calves 1%, sheep 6%, horses and pigs each 0%. For N. caninum, the PCR-prevalence was 2% for adult cows and 0% for all other animal groups. Conversely, the seroprevalences were much higher for both parasite species and all animal groups, with the exception of the fattening pigs. However, as T. gondii was principally detectable in bovine (cows and calves) as well as in sheep meat, the consumption of this meat harbours a potential infection risk for humans. In contrast, the lack of any parasite detectability in fattening pig and horse meat allows to consider this infection source as neglectable when compared to bovine and ovine meat.     

Survey of ovine and caprine toxoplasmosis by IFAT and PCR assays in Sardinia, Italy

During the period 1999-2002, we have analyzed 9639 serum samples and 815 aborted samples (670 fetuses and 145 placenta) from 964 ovine and caprine farms distributed over all Sardinia island. After abortion notification, sera collected at random from adult animals were examined to detect simultaneously IgG and IgM antibodies specific to Toxoplasma gondii by indirect immunofluorescence assay, whereas fetuses and placenta were analyzed by a single tube nested PCR assay. Specific IgG antibodies were detected in 2048 (28.4%) sheep and 302 (12.3%) goats, specific IgM antibodies were found in 652 (9%) sheep and 139 (5.6%) goats. From a total of 2471 ovine and 362 caprine fetal samples including muscle, liver, abomasum, spleen, brain and placenta, 271 (11.1%) ovine and 23 (6.4%) caprine samples were T. gondii PCR-positive. Although T. gondii DNA was amplified from different types of tissues, placenta was the tissue with the highest detection rate. On the one hand, these results indicate that the seroprevalence of T. gondii infection in sheep and goats is relatively high, on the other PCR results demonstrate that T. gondii has a significant role in ovine and caprine abortion. Adequate management might be useful and essential to control the toxoplasmosis in the sheep and goats herds of Sardinia.     

Detection of T. gondii in tissues of sheep and cattle following oral infection.

It has been reported in the literature that cattle are more resistant to toxoplasmosis than sheep. Congenital disease due to T. gondii infection is rarely reported in cattle whereas the parasite is a major cause of abortion and neonatal mortality in sheep. It is believed that sheep remain chronically infected for life. Undercooked meat from infected sheep is an important source of infection for man. In contrast cattle are thought to harbour fewer parasite tissue cysts which may not persist for the lifetime of the host. Therefore, cattle are believed to pose less of a risk for human infection. In this study we examined the presence of T. gondii within a range of tissues in sheep and cattle at 6 weeks and 6 months following oral infection with 10(3) or 10(5) sporulated oocysts of T. gondii. The presence of parasite was determined by bioassay in mice and using polymerase chain reaction (PCR). The results from this study show that T. gondii was more frequently and consistently detected in sheep, in particular within brain and heart tissues, whereas parasites were not detected in the samples of tissues taken from cattle. T. gondii was more frequently detected in sheep given the higher dose of T. gondii. Examination of tissues at either 6 weeks or 6 months after infection did not appear to affect the distribution of T. gondii. The polymerase chain reaction has more specificity and sensitivity when detecting the presence of T. gondii in large animals than histological detection.     

Prevalence of Toxoplasma gondii antibodies in red deer (Cervus elaphus) and other wild ruminants from Spain

Serum samples from 441 red deer (Cervus elaphus) and 161 other wild ruminant species, collected between 1993 and 2005 from six regions of Spain were tested for antibodies against Toxoplasma gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT 1:25 or higher) were detected in 15.6% of red deer. Statistically significant differences were observed among sampling sites with seroprevalence in red deer from Catalonia (42.2%) being significantly higher compared with other Spanish regions (8.7%) (P < 0.05). Statistically significant differences were not observed between T. gondii seroprevalence and sex, age or management of hunting estates (open versus fenced). Seroprevalence of T.gondii infection in other ruminants species was 24% of 79 fallow deer (Dama dama), 21.8% of 33 in roe deer (Capreolus capreolus), 33.3% of three Spanish ibex (Capra pyrenaica), 20% of 10 chamois (Rupicapra pyrenaica), 10% of 10 barbary sheep (Ammotragus lervia), and 14.8% of 27 mouflon (Ovis ammon) in areas not including Catalonia, where no samples from these species were available. Serological results indicated a widespread exposure to T. gondii among wildlife in Spain and suggest that consumption of raw or inadequately cooked meat, as well as handling carcasses of wild game, should be taken into account as a source of infection for humans.     

龙岩市部分地区牛、羊弓形虫病的血清学调查

目的：采集龙岩市部分地区牛、羊血清,检测福建省牛和羊弓形虫病的感染情况。方法：应用酶联免疫吸附试验检测牛和羊血清弓形虫IgG抗体。结果：49份牛血清弓形虫IgG抗体均呈阴性;35份羊血清中,8份弓形虫IgG抗体呈阳性,阳性率为22．86％（8／35）。结论：龙岩市部分地区羊弓形虫的感染率较高,应引起人们重视。     

Prevalence and genotypes of Toxoplasma gondii in feline faeces (oocysts) and meat from sheep, cattle and pigs in Switzerland

The protozoan parasite Toxoplasma gondii infects almost all warm blooded animal species including humans, and is one of the most prevalent zoonotic parasites worldwide. Post-natal infection in humans is acquired through oral uptake of sporulated T. gondii oocysts or by ingestion of parasite tissue cysts upon consumption of raw or undercooked meat. This study was undertaken to determine the prevalence of oocyst-shedding by cats and to assess the level of infection with T. gondii in meat-producing animals in Switzerland via detection of genomic DNA (gDNA) in muscle samples. In total, 252 cats (44 stray cats, 171 pet cats, 37 cats with gastrointestinal disorders) were analysed coproscopically, and subsequently species-specific identification of T. gondii oocysts was achieved by Polymerase Chain Reaction (PCR). Furthermore, diaphragm samples of 270 domestic pigs (120 adults, 50 finishing, and 100 free-range animals), 150 wild boar, 250 sheep (150 adults and 100 lambs) and 406 cattle (47 calves, 129 heifers, 100 bulls, and 130 adult cows) were investigated by T. gondii-specific real-time PCR. For the first time in Switzerland, PCR-positive samples were subsequently genotyped using nine PCR-restriction fragment length polymorphism (PCR-RFLP) loci (SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) for analysis. Only one of the cats shed T. gondii oocysts, corresponding to a T. gondii prevalence of 0.4% (95% CI: 0.0-2.2%). In meat-producing animals, gDNA prevalence was lowest in wild boar (0.7%; 95% CI: 0.0-3.7%), followed by sheep (2.0%; 95% CI: 0.1-4.6%) and pigs (2.2%; 95% CI: 0.8-4.8%). The highest prevalence was found in cattle (4.7%; 95% CI: 2.8-7.2%), mainly due to the high prevalence of 29.8% in young calves. With regard to housing conditions, conventional fattening pigs and free-range pigs surprisingly exhibited the same prevalence (2.0%; 95% CI: 0.2-7.0%). Genotyping of oocysts shed by the cat showed T. gondii with clonal Type II alleles and the Apico I allele. T. gondii with clonal Type II alleles were also predominantly observed in sheep, while T. gondii with mixed or atypical allele combinations were very rare in sheep. In pigs and cattle however, genotyping of T. gondii was often incomplete. These findings suggested that cattle in Switzerland might be infected with Toxoplasma of the clonal Types I or III, atypical T. gondii or more than one clonal Type.     

Toxoplasmosis in Sheep: Epidemiological Studies in Flocks with Reproductive Loss from Toxoplasmosis

The epidemiology of toxoplasmosis was studied in 51 flocks with reproductive loss from the infection. Overt toxoplasmosis was diagnosed on 2–4 neighbouring farms on 6 occasions, involving a total of 15 flocks. In 14 of the 51 flocks the frequency of abortion was highest in a definite part or age group of the flock.Evidence was found that the source of infection may be confined to a particular part of an area or of a farm. There was apparently no transmission of Toxoplasma gondii from sheep with overt or latent toxoplasmosis to susceptible sheep. There were good reasons to believe that the parasite might have been transmitted via the silage in 1 of the flocks.