A sero-epidemiological survey of Toxoplasma gondii infection in free-range and caged chickens in northeast China

Acquisition of Toxoplasma gondii infections is mainly through ingestion of parasite-contaminated food. T. gondii oocyst distribution in the living environment of human and livestock is directly linked to the prevalence of the parasite infection in humans and domestic animals. In this study, we investigated the sero-prevalence of T. gondii infection in free-range as well as caged chicken in northeast China. The purpose of this study was to investigate the potential prevalence of T. gondii oocysts in the environments. Sera of 308 free-range chickens and 210 caged chickens collected in three areas in northeast China were tested for anti-T. gondii antibodies with ELISA assays. The infection rates of free-range and caged chickens were 34.7% and 2.8% respectively, indicating that the parasite is widely distributed in the environment and poses threatens to the health of people living in those areas.     

Toxoplasma gondii infection in domestic ducks, free-range and caged chickens in southern China

Toxoplasma gondii is widely distributed in humans and other animals including domestic poultry throughout the world, but little is known of the prevalence of T. gondii in chickens and ducks in People's Republic of China. In the present study, antibodies to T. gondii were investigated in 349 domestic ducks (Anas spp.), 361 free-range, and 244 caged chickens (Gallus domesticus) raised in commercial flocks in Southern China's Guangdong Province using the modified agglutination test (MAT). Antibodies to T. gondii (MAT titer of 1:5 or higher) were found in 56 (16%) of 349 ducks, 41 (11.4%) of 361 free-range, and 10 (4.1%) of 244 caged chickens. The results indicate soil contamination due to T. gondii oocysts because free-range chickens feed from the ground, and suggest that the meat from the domestic poultry may be an important source for human infection by T. gondii in People's Republic of China.     

Prevalence of IgG Antibodies to Toxoplasma gondii in Veterinary and Undergraduate Students at Virginia Tech,Blacksburg, Virginia

Toxoplasma gondii is a globally distributed parasitic protozoan that infects humans and other warm‐blooded vertebrates. Felids are the only definitive host for T. gondii, and they excrete oocysts in their faeces. The national prevalence in humans is declining in the United States. This zoonotic organism is of particular interest due to its importance in pregnant women, in individuals with altered immune systems, and in reactivated ocular infections. Exposure to the parasite in humans is usually associated with consumption of raw or undercooked meat or by accidental ingestion of oocysts. It was hypothesized that veterinary students would have a greater chance at exposure to the parasite than an average population of undergraduate students due to increased contact with cats who are infected. A commercially available ELISA was used to examine serum samples from 336 students (252 veterinary students and 84 undergraduate students) at Virginia Polytechnic Institute and State University and the Virginia‐Maryland Regional College of Veterinary Medicine for serum IgG antibodies to T. gondii antigen. The prevalence of T. gondii in these subjects was 5.6% in veterinary school students (n = 252) and 2.4% in undergraduates (n = 84). There was no significant difference (P > 0.05) in the prevalence of T. gondii antibodies in veterinary versus undergraduate students. The overall prevalence of 4.8% in all students in this study reflects the continuing decline of antibodies to T. gondii in humans in the United States.     

Infection with Toxoplasma gondii during Pregnancy: Seroepidemiological Studies in Austria

Seropositivity among pregnant woman in Austria has decreased from 48% to 50% at the end of the 1970s to 35% in recent years. Despite this decrease, knowledge of possible sources and risk factors for Toxoplasma infection remains important. We reviewed seroepidemiological studies that were undertaken to assess the roles of undercooked meat and oocysts in cat faeces as potential sources of infection in pregnant women. Improved management and hygiene in pig herds raised in confinement have resulted in less contact of pigs with cats and a decrease of infected pigs within one decade from 14% in 1982 to 0.9% in 1992. In Austrian wild boar populations, however, seroprevalences remained essentially unchanged during the same decade (18% in 1983 and 19% in 1990–1993). Austrian sheep and goats are usually kept on small farms where cats abound and are predominantly seropositive (66% in sheep and 69% in goats). The seroprevalence in cats has decreased from approximately 81% in 1987 to 59% in 1996; presumably because of cats’ increased consumption of processed food. Despite the decrease of infection in pregnant women via the cat‐to‐pig pathway, it may be offset by a recent concomitant increase in mutton consumption. Free‐ranging chickens are a good indicator of the prevalence of T. gondii oocysts in the soil because chickens are ground feeders. Antibodies to T. gondii, as evaluated by the modified agglutination test, were found in 36% of chickens from 12 Austrian ‘biofarms’. Because Austrians rarely consume raw pork, the fraction of human T. gondii infections associated with pig meat consumption is likely small. As meat consumption and lifestyle patterns change in Austria, the risk of human infection with T. gondii via different pathways needs re‐evaluation and targeted educational efforts to control transmission.     

Serological Survey of Toxoplasma gondii Infection in the Domestic Goose (Anser domestica) in Southern China

In the present study, the antibodies to Toxoplasma gondii in 191 farm‐bred and 83 house‐bred geese (Anser domestica) were assessed for the prevalence of T. gondii infection in southern China with the modified agglutination test. Antibodies to T. gondii (MAT ≥ 1 : 5) were found in 27 (14.14%) of farm‐bred geese and 14 (16.87%) of house‐bred geese. Geese infected with T. gondii may be a source of T. gondii infection for humans and cats.     

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

ObjectiveToxoplasma gondii is a protozoan parasite that is widely prevalent in most warm-blooded vertebrates. Humans mainly become infected by eating raw or undercooked meat. This study was designed to investigate the infection of cattle with T. gondii in Jahrom, southern Iran.MethodsTissue samples consisting of heart, diaphragm, and tongue were collected from 125 slaughtered cattle. DNA samples were extracted from the homogenized tissues. T. gondii was detected and genotyped using nested-polymerase chain reaction (Nested-PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based on GRA6 and SAG2 (3', 5' terminal regions) genes, respectively.ResultsThe prevalence of T. gondii DNA was 56% in cattle. The most infected tissue was the diaphragm (54.4%) followed by the heart (48.8%) and tongue (43.2%). Type II was the most prevalent genotype (70%) among T. gondii isolates.ConclusionIn this study, the high prevalence of T. gondii infection in cattle meat indicates the important role of cattle in the transmission of infection to humans. Therefore, incorporating the correct method of consuming meat in health education programs is crucial to prevent human infection.     

Pigeons (Columba livia) are a suitable experimental model for Neospora caninum infection in birds

Neospora caninum infections in chickens have been recently described by epidemiological and experimental approaches, and these birds may be considered natural intermediate hosts of the parasite. It has been postulated that other bird species might perform this role in wildlife as well. To better understand the sylvatic life cycle of N. caninum, further studies are required. In that sense, this work aimed to observe infection kinetics in pigeons experimentally infected with N. caninum. Experimental infections were conducted in parallel with a related protozoan, Toxoplasma gondii, which has been already described as able to infect pigeons in nature. Our results demonstrated that N. caninum disseminated through various tissues of this host and induced parasite-specific IgG seroconversion. Infection parameters were similar to that observed in the T. gondii infected group, although N. caninum-infected pigeons presented lower IgG titers during acute phase. The results herein described demonstrate that pigeons are a suitable model for N. caninum infection, considering that these data are in agreement with those observed in chickens experimentally infected with this parasite. As pigeons may be revealed as important reservoirs for N. caninum infection in nature, future studies are necessary to determine the real prevalence of this parasite in this and other birds in wildlife.     

A serologic study on Toxoplasma gondii infection in slaughtered sheep and goats in Qazvin Province,Iran

Background

Toxoplasma gondii is a common protozoan parasite among all mammals, in particular small ruminants, worldwide. Traditional husbandry can be a major risk factor for infection of sheep and goats with this parasite.

Objectives

The present study aimed to determine the current status of the prevalence for T. gondii in livestock of Qazvin Province.

Methods

In this cross-sectional study, the sera of 455 sheep and 375 goats were examined to detect anti-Toxoplasma IgG antibodies by using in-house indirect ELISA.

Results

Overall, 33.62% (153/455) of sheep and 36.41% (130/375) of goats were positive for anti-Toxoplasma IgG antibodies with no statistically significant difference. The prevalence rate of T. gondii among the sheep of Qazvin County was significantly higher than in Abyek and Abhar counties (p < 0.001).

Conclusions

The results of the present study indicate that the prevalence of T. gondii in sheep and goats of the study area is high. Therefore, the meat of the animals reared in this area can be a potential source of human infections by this parasite.

     

A Brief History and Overview of Toxoplasma gondii

Toxoplasma gondii was discovered by scientists working in North Africa and Brazil around 100 years ago. The parasite has since been found to be capable of infecting all warm‐blooded animals including humans making it one of the most successful parasitic organisms worldwide. The pathogenic potential of T. gondii was recognized in the 1920s and 1930s, in congenitally infected children presenting with the classic triad of symptoms, namely hydrocephalus, retinochoroiditis and encephalitis. In addition, around the same time T. gondii parasites were found to be associated with severe intraocular inflammation. In the 1980s, T. gondii emerged as a major cause of death in patients with acquired immunodeficiency syndrome, illustrating the importance of the immune system in controlling T. gondii infection. T. gondii was reported as a major cause of abortion in sheep in New Zealand in the 1950s, which raised questions about potential new transmission routes for the parasite. The discovery of the cat as the definitive host in the 1960s was a very important finding as it helped to complete our understanding of the parasite’s life cycle, and the oocyst stage of T. gondii shed in the faeces of infected cats was found to be an important source of infection for many intermediate hosts and helped to explain infection in herbivorous animals and people with a vegetarian diet. In addition, this stage of the parasite was very robust and could survive in the environment, depending on the climatic conditions, for up to 12–18 months. Knowledge of the parasite’s lifecycle, transmission routes, risk groups and host immune responses has helped in the development of strategies to control the disease, reduce transmission of the parasite and limit environmental contamination.     

Majority of T. gondii seropositive chickens (Gallus domesticus) in Central Ethiopia carries the infective parasite

Background

The prevalence of Toxoplasma gondii in free range chickens is a good indicator of the prevalence of T. gondii oocysts in the environment. The aim of this study was to isolate T. gondii parasites from heart and brain of seropositive free range (FR) chickens.

Findings

Isolation of T. gondii from pooled heart and brain of 41 direct agglutination test (DAT) positive (≥1:40) free range chickens (Gallus domesticus) was carried out by bioassay in mice. T. gondii specific antibodies in mice were assayed by DAT and microscopy was employed for detection and enumeration of brain tissue cysts. Overall, bioassay was positive in 29 (70.7%) chicken samples. T. gondii tissue cysts were isolated from 59% (24/41) of bioassayed chickens: from 2 of 7 chickens with a titer of 1: ≤ 60, 2 of 5 with titer 1: 180, 6 of 8 with titer 1: 540, 10 of 15 with titer 1: 1620, 1 of 2 with titer 1: 6000, 2 of 3 with titer 1:18000, 1 of 1 with titer 1:54000. None of the isolates was pathogenic for mice. Tissue cysts were detected from 61% of seropositive mice (DAT ≥ 1:40). Generally, tissue cyst counts per brain of mouse were low (mean: 132.7 ± 84.4; range: 47–352).

Conclusions

Majority of T. gondii seropositive chickens (Gallus domesticus) in Central. Ethiopia carries the infective parasite. Tissues from the free range chicken might be a source infection for animals and humans.     

Toxoplasma gondii infection in Colombia with a review of hosts and their ecogeographic distribution

Toxoplasma gondii is one of the most prevalent zoonotic protozoan parasites among warm‐blooded animal populations (humans included) around the world, causing multiple clinic manifestations including death in the most severe cases of infection. Due to the versatile life cycle of T. gondii and its diversity of potential hosts, there is a common perception that natural areas and wildlife are highly prevalent reservoirs for the parasite; however, information and reports of the parasite on wildlife populations in Colombia are scarce. Using PRC‐based detection analyses of the B1 gene, we evaluated the presence of T. gondii in 49 native small mammal species (10% of the mammal species of Colombia) from 4 different undisturbed natural habitats. Additionally, to understand the ecogeographical distribution of the parasite in Colombia, we developed a literature search of infection reports including information on the host species, density of records and occurrence patterns (using landcover and ecoregions) in natural, rural and urban areas. Our literature review showed a total of 8,103 reports of T. gondii for Colombia of which 86% were related to humans, and 14% to non‐human mammals and other categories, with just a single report associated to wildlife; additionally, 82% of all reports were associated to urban areas whereas only 18% to rural sites. Based on the negative results for the presence of T. gondii in our PCR‐based analyses and our literature search, we suggest that T. gondii has a synanthropic distribution in Colombia occurring in ecoregions as variable as the xeric scrubs in the northern lowlands and humid montane Andean forests, also we show a lack of information on the parasite relationship with wildlife, a concerning fact given that zoonoses are the leading mechanism for the emergence of infectious diseases.     

Prevalence of Toxoplasma gondii antibodies in stray cats in Sari, northern Iran

Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete environmentally resistant oocysts. T.gondii is a major zoonotic agent which infects up to one-third of the world population. Toxoplasmosis in neonates and immunocompromised patients can lead to severe disease and death. A cross- sectional parasitological and serological survey with latex agglutination test (LAT) to detect anti-T. gondii antibodies was conducted on 100 serum samples collected from stray cats in five urban areas of Sari, Northern Iran, from April to November 2004. Classification by age, sex, weight, season and region was made. Results analyzed according to specific variables. The overall prevalence of T. gondii IgG antibodies (LAT titre ≥1:1) were found in 40 of 100(40%) of stray cats, with regional variations. Overall 16 of 100(16%) of stray cats had diagnostically significant antibody titres (LAT ≥ 1:64). Prevalence was significantly higher in adult cats (1.5–3.0 kg, 54.5% of 66) than in juvenile cats and kittens (≤1.4 kg, 11.8% of 34) and higher in female stray cats (44.4% of 72) than in male stray cats (28.6% of 28). Toxoplasma seroprevalence was highest in the season of spring (22.4%). There was a significant difference in the prevalence of infection relative to host age and weight (P < 0.05). No significant difference was found between the prevalence of infection relative to host gender, urban sites and season (P > 0.05). Prevalence of T. gondii oocyst was also analyzed by a routine coprological method in 100 cats. T. gondii oocysts were not found in any faecal samples analyzed. Only 2 out of 100 smear preparations of intestinal mucosa showed trophozoites of T. gondii.     

Antibody Prevalence and Risk Factors for Toxoplasma gondii Infection in Women from Multan,Pakistan

Toxoplasma gondii infections are prevalent in humans and warm‐blooded animals. Maternal infections during pregnancy may have devastating consequences for transplacentally infected neonates. This study was conducted to examine the seroprevalence of antibodies to T. gondii in pregnant women of childbearing age and determine risk factors associated with pregnancy history, pet ownership, social and cultural factors at Nishtar Hospital, Multan. Samples were collected from 403 women and examined using a commercially available enzyme‐linked immunosorbent assay (ELISA). The overall prevalence of antibodies to T. gondii was 17.6% (71) in the 403 samples collected from women. Antibodies to T. gondii were present in 19.4% (45) of 232 pregnant women and 15.2% (26) of the samples from 171 non‐pregnant women. This study identified miscarriage history, pet ownership, type of residence, marital status, source of drinking water and eating habits as significant (P < 0.05) risk factors associated with the presence of antibodies to T. gondii infection. Seroprevalence was not significantly different (P > 0.05) in women from different ethnic groups based upon lifestyle and culture.     

Prevalence of <Emphasis Type="Italic">Toxoplasma gondii</Emphasis> and <Emphasis Type="Italic">Neospora caninum</Emphasis> infections in sheep from Federal District,central region of Brazil

Serum samples from 1028 sheep were collected from 32 herds within Federal District, in the central region of Brazil. The samples were examined by indirect fluorescent antibody test (IFAT) using sera diluted 1:64 and 1:50 as cut-off values for the detection of antibodies against Toxoplasma gondii and Neospora caninum, respectively. The observed prevalence for T. gondii infection was 38.22% (26.81%<CI 0.95<49.62%), and the titers ranged from 64 to 65536. The observed prevalence for N. caninum infection was 8.81% (7.08%<CI 0.95<10.53%). The titers ranged from 50 to 51200. The reactant sera to both pathogens corresponded to 4.67% of the samples. The risk factors were not determined because of the absence of negative herds for T. gondii and the high proportion of positive herds for N. caninum (87.50%). The prevalence for T. gondii infection was significantly higher among males than in females. The present work is the first report on seroprevalence of T. gondii and N. caninum in sheep from Federal District and shows that infection by both parasites is widespread in the ovine population from this region.     

Prevalence, biology, pathology, and public health importance of linguatulosis of camel in Iran

Linguatula serrata is a cosmopolitan zoonotic parasite with its adult form occurring in the nasal and respiratory passages of canids as the definitive hosts, while its immature stages localize in the mesenteric lymph nodes, liver, spleen, lungs, and, rarely, in other organs, such as the ocular region of herbivorous intermediate hosts. Humans can behave as both intermediate and final host and are infected by visceral and nasopharyngeal linguatulosis. Consumption of infected, improperly cooked viscera of the intermediate hosts, including sheep, goats, cattle, camels, or other herbivores containing the larval stages of this parasite is a potential source of infection of human beings with the nasopharyngeal form of linguatulosis. However, nasopharyngeal secretions or feces of carnivores containing eggs of Linguatula are the main sources for infecting human beings with the visceral form of this infection. In the present study, the prevalence of infection by nymphs of L. serrata in 101 camels in Yazd Province, central Iran, was estimated based on histopathological studies of samples from two, apparently enlarged, mesenteric lymph nodes (MLN), together with one sample from a whitish pinpoint spot on the liver and spleen of each animal. Thirteen camels (12.9%) were infected with the nymphal stage of L. serrata. Age and sex did not play a significant role in the prevalence of this parasitic infection. The number of parasites in each MLN ranged from one to six larvae. In view of the consumption of raw or undercooked liver and visceral organs of camel by humans of this region, the importance of careful inspection at slaughter needs to be emphasized.     

Occurrence of anti-<Emphasis Type="Italic">Toxoplasma gondii</Emphasis> antibodies in female cattle in south-west of Iran

Toxoplasmosis, caused by Toxoplasma gondii, is a significant disease in livestock and humans. In Iran, studies shows that T. gondii infection in humans is relatively high and prevalence is associated mainly with consumption of undercooked meat or meat products. We have examined 450 serum samples from female cattle distributed over all Ahvaz, the center of Khouzestan province, south-west of Iran. IgG antibodies to T. gondii were assayed by the modified agglutination test using whole tachyzoites of T. gondii, and found in 71 (15.77%) of 450 cattle with titers of 1:25 in 38, 1:50 in 18, 1:100 in 11, 1:200 in three and 1:400 in one. Titers of antibodies were decreased in cattle over 2 years old. These results indicate that T. gondii infection in cattle of Khouzestan is relatively considerable, but not very high and consumption of beef may be a source of infection for humans in south-west of Iran.     

Prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from Mossoró, Rio Grande do Norte, Brazil

Toxoplasma gondii is an obligate intracellular parasite with a variety of hosts, responsible for reproductive problems and economic losses in sheep flocks. Neospora caninum was recently identified and its clinical presentation in sheep is similar to that of toxoplasmosis, which can cause repeated abortions, though less frequently in this species. In order to confirm the prevalence of these agents in the city of Mossoró, Rio Grande do Norte, Brazil, 409 serum samples from adult sheep (364 females and 45 males) were tested by the indirect immunofluorescence antibody test, using cut-off point at a dilution of 1:64 and 1:50 for T. gondii and N. caninum, respectively. From the 35 properties examined, 23 (65.7%) had at least one seropositive animal for T. gondii and six (17.1%) for N. caninum. The prevalence of seropositive animals for T. gondii was 20.7% and for N. caninum 1.8%. There was no association between the presence of the agent’s antibody and gender, reports of reproductive problems and presence of dogs and/or cats in the properties. T. gondii is well distributed and N. caninum has low prevalence in sheep and in the properties of the studied region.     

Toxoplasma gondii in Ireland: Seroprevalence and Novel Molecular Detection Method in Sheep,Pigs, Deer and Chickens

Toxoplasma gondii is among the most studied parasites worldwide but there is not much information about it published in Ireland. The objectives of this study were to determine the seroprevalence of T. gondii in sheep, pigs, deer and chickens and the molecular detection of T. gondii DNA in muscle tissue. Serum samples were collected from these species at the time of slaughter at Irish abattoirs during 2007 and tested for anti‐T. gondii antibodies using a commercial semi‐quantitative latex agglutination test. Antibodies (titre ≥1 : 64) were found in 36% (105/292) sheep, 4.7% (15/317) pigs and 6.6% (23/348) deer. In chickens, 18% (65/364) had antibody titres, ranging between 1 : 5 and 1 : 1024. Significant (P ≤ 0.05) age‐related differences in seroprevalence were found in adult sheep (58.1%) and pigs (23.1%). Significant gender differences in seroprevalence was also found in sheep with more females (43%) than males (22.4%) being positive. However, when adjusted for age through logistic regression gender was no longer significant. Seroprevalence was also evaluated on farm locations grouped to NUTS level 3, but the prevalence was too low to draw any statistical conclusions. Using a nested PCR, the presence of T. gondii DNA was detected in diaphragm samples from 3.6% (3/83) sheep, 13.0% (3/23) pig and 4.2% (3/71) deer. Meat digestion liquids from a Trichinella spp. survey in pigs were also used for the first time to detect T. gondii. Toxoplasma gondii DNA was detected in 50% (10/20) of pooled samples. This is the first in depth study of T. gondii seroprevalence in animals in Ireland and a novel method, using digestion liquid from pooled diaphragm samples, for PCR detection in pigs is described.     

Seroprevalence of <Emphasis Type="Italic">Toxoplasma gondii</Emphasis> infection in breeding sows in Western Fujian Province,China

The objective of the present investigation was to estimate the seroprevalence T. gondii infection in breeding sows in Western Fujian Province, the People’s Republic of China. Sera collected from breeding sows during 2006–2007 from 6 different regions in Western Fujian Province were assayed for antibodies to T. gondii by an indirect hemagglutination antibody (IHA) test. Antibodies to T. gondii were detected in 87 (14.38%) of 605 breeding sows. Differences in seroprevalence were observed between sampling regions, ranging from 10.14% to 37.50%. The present investigation demonstrated that the prevalence of T. gondii infection in breeding sows in Fujian Province was high. Integrated control strategies and measures should be implemented to prevent and control T. gondii infection in breeding sows, which in turn will have significant implications for the control of human infection with T. gondii in this province.