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.     

Toxoplasma gondii Infections in Chickens (Gallus domesticus): Prevalence,Clinical Disease,Diagnosis and Public Health Significance

Chickens are considered one of the most important hosts in the epidemiology of Toxoplasma gondii infection because they are an efficient source of infection for cats that excrete the environmentally resistant oocysts and because humans may become infected with this parasite after eating undercooked infected chicken meat. The objective of this study is to review worldwide prevalence of T. gondii infection in chickens and to assess the role of infected chickens in the epidemiology of toxoplasmosis in humans. A very high prevalence of the parasite was found in chickens raised in backyards (up to 100%) and free‐range organic (30–50%) establishments.     

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.     

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.     

Seroprevalence of Toxoplasma gondii infection in Norwegian dairy goats

Background

Toxoplasma gondii is a major problem for the sheep industry as it may cause reproduction problems. The importance of T. gondii in Norwegian goat herds is uncertain, but outbreaks of toxoplasmosis in dairy goat farms have been recorded. The aim of this study was to describe the prevalence of T. gondii infection in Norwegian dairy goats by using serology.

Findings

Goat serum originally collected as part of two nationwide surveillance and control programmes between 2002 and 2008 were examined for T. gondii antibodies by using direct agglutination test. In total, 55 of 73 herds (75%) had one or more serologically positive animals, while 377 of 2188 (17%) of the individual samples tested positive for T. gondii antibodies.

Conclusions

This is the first prevalence study of T. gondii infection in Norwegian goats. The results show that Norwegian goat herds are commonly exposed to T. gondii. Nevertheless, the majority of goat herds have a low prevalence of antibody positive animals, which make them vulnerable to infections with T. gondii during the gestation period.     

Latitudinal variability in the seroprevalence of antibodies against Toxoplasma gondii in non-migrant and Arctic migratory geese

Toxoplasma gondii is an intracellular coccidian parasite found worldwide and is known to infect virtually all warm-blooded animals. It requires a cat (family Felidae) to complete its full life cycle. Despite the absence of wild felids on the Arctic archipelago of Svalbard, T. gondii has been found in resident predators such as the arctic fox and polar bear. It has therefore been suggested that T. gondii may enter this ecosystem via migratory birds. The objective of this study was to identify locations where goose populations may become infected with T. gondii, and to investigate the dynamics of T. gondii specific antibodies. Single blood samples of both adults and juveniles were collected from selected goose species (Anser anser, A. brachyrhynchus, Branta canadensis, B. leucopsis) at Arctic brood-rearing areas in Russia and on Svalbard, and temperate wintering grounds in the Netherlands and Denmark (migratory populations) as well as temperate brood-rearing grounds (the Netherlands, non-migratory populations). A modified agglutination test was used on serum, for detection of antibodies against T. gondii. Occasional repeated annual sampling of individual adults was performed to determine the antibody dynamics. Adults were found seropositive at all locations (Arctic and temperate, brood-rearing and wintering grounds) with low seroprevalence in brood-rearing birds on temperate grounds. As no juvenile geese were found seropositive at any brood-rearing location, but nine month old geese were found seropositive during spring migration we conclude that geese, irrespective of species and migration, encounter T. gondii infection in wintering areas. In re-sampled birds on Svalbard significant seroreversion was observed, with 42% of seropositive adults showing no detectable antibodies after 12 months, while the proportion of seroconversion was only 3%. Modelled variation of seroprevalence with field data on antibody longevity and parasite transmission suggests seroprevalence of a population within a range of 5.2–19.9%, in line with measured values. The high occurrence of seroreversion compared to the low occurrence of seroconversion hampers analysis of species- or site-specific patterns, but explains the absence of an increase in seroprevalence with age and the observed variation in antibody titre. These findings imply that even though infection rate is low, adults introduce T. gondii to the high Arctic ecosystem following infection in temperate regions.     

Serological survey for antibodies to Encephalitozoon cuniculi and Toxoplasma gondii in pet rabbits in eastern coastal areas of China

Encephalitozoon cuniculi (E. cuniculi) is a microsporidian parasite commonly detected in rabbits and can infect humans and cause encephalitozoonosis. And Toxoplasma gondii is a prevalent parasite distributed worldwide and can infect almost all warm-blooded animals, including humans. The aim of the current study was to investigate the seroprevalence of E. cuniculi and Toxoplasma gondii, and risk factors of infection in pet rabbits reared in eastern coastal areas of China (Tianjin, Shandong, Jiangsu, Zhejiang, Shanghai and Fujian). Total 222 blood samples of pet rabbits were collected from local veterinary hospitals. The seropositivity rates of E. cuniculi were 16.22% (36/222) according to an Enzyme-linked immunosorbent assay (ELISA). Female pet rabbits was significantly higher than that in males (P=0.002), Zhejiang were markedly higher than those in Jiangsu and Shanghai (P=0.017, P=0.022), and cross-breed rabbits were dramatically higher than those in Chinchilla, New Zealand white, Rex (P=0.02, P=0.006, P=0.008). The seroprevalence of T. gondii was 13.06% (29/222) by the method of ELISA. The seroprevalence in Zhejiang was significantly higher than that in Shanghai (P=0.017). No difference in seroprevalence was detected with respect to the gender, age, species, health status, or season. These findings show that E. cuniculi and T. gondii are present and spread in pet rabbits. Therefore, pet rabbits should be considered as an important reservoir of encephalitozoonosis for humans and maybe important implication for public health in eastern coastal areas of China.     

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.

     

Seroprevalence of Toxoplasma gondii and Neospora caninum in wild and domestic ruminants sharing pastures in Galicia (Northwest Spain)

The prevalence of antibodies to the protozoan parasites Toxoplasma gondii and Neospora caninum were investigated by the direct agglutination test (DAT) and cELISA, respectively, in 160 roe deer (Capreolus capreolus), 177 sheep and 178 cattle sharing pastures in Galicia (Northwest Spain). The seroprevalence for T. gondii was 13.7% in roe deer, 57% in sheep and 7.3% in cattle. The seroprevalence for N. canimum was 6.8%, 10.1% and 24.1% in roe deer, sheep and cattle, respectively. Statistically significant differences were observed between sheep and the other species for T. gondii and between cattle and the other ruminants for N. caninum. Only 19/515 animals were positive for both, T. gondii and N. caninum. Statistically significant differences were observed among different geographical areas for T. gondii but not for Neospora, seroprevalence being higher in the coastal area lower than in other areas. This study reveals a widespread exposure to T. gondii in Galician ruminants, and therefore, those species, particularly sheep, should be regarded as a potential source of infection for humans.     

Sero-epidemiological investigation of bovine toxoplasmosis in traditional and smallholder cattle production systems of Tanga Region,Tanzania

In view of the worldwide importance of Toxoplasma gondii and the fragmented information on the seroprevalence of the disease in animals in Tanzania, a study, using the modified Eiken latex agglutination test (LAT), was conducted from May 2003 to January 2004 to determine the prevalence of antibody to T. gondii in 130 randomly selected farms comprising 655 cattle. The overall seroprevalence of T.gondii antibodies in cattle and farms were 3.6% and 13%, respectively. Risk factors for animal and herd-level toxoplasmosis seropositivity were tested using multivariable logistic regression to control for confounding factors. Cattle managed under traditional husbandry practises were more likely to be seropositive than those managed under smallholder practises (48% versus 4.7%; p < 0.01). Herd size of ≥ 9 cattle were at greater risk of acquiring infection than herds holding fewer animals [≤ 9 cattle], (odd ratio [OR] = 3.99; 95% confidence interval [CI], 0.97–16.48; P = 0.001). We concluded that seroprevalence at herd level was high and relatively low at animal level, possibly due to the reduced susceptibility of cattle to T.gondii infection as compared to goats and sheep. The high seroprevalence in animals managed by traditional husbandry practise suggests that the parasite is widely distributed in the environment and could pose a public health threat to the people living in those areas.     

Molecular genotyping and serological evaluation of Toxoplasma gondii in mothers and their spontaneous aborted fetuses in Southwest of Iran

BackgroundGiven the lack of routine screening and the high prevalence of toxoplasmosis in pregnant women in Iran, the current study aimed to find out the rate and features of Toxoplasma gondii infection in the spontaneously aborted human fetuses in Kohgiluyeh and Boyer-Ahmad Province, Southwestern Iran.MethodsThis cross-sectional study was performed on 100 spontaneously aborted fetuses’ tissues and their mother blood samples. The mothers’ sera were evaluated for anti-Toxoplasma antibodies while their buffy coat and aborted fetuses tissues were evaluated for Toxoplasma DNA. PCR product at GRA6 locus was sequenced and phylogenetic analysis was done. Likewise, quantitative Real-Time PCR was performed to find out the parasite burdens in mothers buffy coat and fetuses tissues.ResultsUsing serological method, anti-Toxoplasma IgG and IgM antibodies were detected in 7 (7%) and 3 (3%) out of 100 sera from women with spontaneous abortion. Real-time PCR method detected T. gondii DNA in the buffy coat of one seronegative and 2 (out of 3) IgM seropositive cases. None of the samples from aborted fetuses were infected with T. gondii. BLAST and phylogenetic analysis showed that the sequenced isolates belonged to type I of T. gondii and two identified T. gondii isolates were taxonomically grouped into one clade.ConclusionOur findings revealed type I genotype of T. gondii in two mothers with spontaneous abortion, without fetus involvement. It is necessary to examine more aborted fetuses’ samples from different geographical areas to determine the association between Toxoplasma genotype and abortion.     

Serological survey of Toxoplasma gondii in captive nonhuman primates in zoos in Spain

Toxoplasma gondii is a widely distributed zoonotic protozoan parasite, which can affect most warm-blooded species. Some species of non-human primates (NHPs) are highly susceptible to T. gondii infection. The aim of the study was to determine the seroprevalence and risk factors associated with T. gondii infection in NHPs housed in zoos in Spain. Sera from 189 NHPs belonging to 33 species were collected in eight zoos. Additionally, 10 of the 189 animals were longitudinally sampled. Anti-T. gondii antibodies were detected in 48 NHPs (25.4%; confidence interval of 95% (CI_95%): 19.2–31.6) using a modified agglutination test (MAT; cut-off = 25). Seropositive animals had titers of 25 (6.3%), 50 (8.3%), 100 (8.3%) and ≥500 (68.8%). Seropositivity was detected in 15 of the 33 species (45.5%). Of the 10 NHPs sampled more than once, two animals (one Barbary macaque [Macaca sylvanus] and one common chimpanzee [Pan toglodytes]) seroconverted along the study period, while one seropositive chimpanzee increased antibody titers over time. The Hominidae family (OR = 5.9; CI_95%: 2.7–12.8) and sex (females) (OR = 2.1; CI_95%: 1.1–4.1) were risk factors potentially associated with seropositivity to T. gondii. Our results evince a widespread circulation of T. gondii in NHPs in zoos in Spain, which may be of conservation concern. Control measures should be implemented to minimize the risk of exposure of these species to T. gondii.     

Vaccination of pigs with the S48 strain of Toxoplasma gondii – safer meat for human consumption

As clinical toxoplasmosis is not considered a problem in pigs, the main reason to implement a control strategy against Toxoplasma gondii (T. gondii) in this species is to reduce the establishment of T. gondii tissue cysts in pork, consequently reducing the risk of the parasite entering the human food chain. Consumption of T. gondii tissue cysts from raw or undercooked meat is one of the main sources of human infection, with infected pork being considered a high risk. This study incorporates a mouse bioassay with molecular detection of T. gondii DNA to study the effectiveness of vaccination (incomplete S48 strain) in its ability to reduce tissue cyst burden in pigs, following oocyst (M4 strain) challenge. Results from the mouse bioassay show that 100% of mice which had received porcine tissues from vaccinated and challenged pigs survived compared with 51.1% of mice which received tissues from non-vaccinated and challenged pigs. The presence (or absence) of T. gondii DNA from individual mouse brains also confirmed these results. This indicates a reduction in viable T. gondii tissue cysts within tissues from pigs which have been previously vaccinated with the S48 strain. In addition, the study demonstrated that the main predilection sites for the parasite were found to be brain and highly vascular muscles (such as tongue, diaphragm, heart and masseter) of pigs, while meat cuts used as human food such as chop, loin, left tricep and left semitendinosus, had a lower burden of T. gondii tissue cysts. These promising results highlight the potential of S48 strain tachyzoites for reducing the number of T. gondii tissues cysts in pork and thus improving food safety.     

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.     

Molecular study and genotyping of Cryptosporidium baileyi and Cryptosporidium parvum from free-range and commercial broiler chickens in Guilan province,Iran

Cryptosporidiosis acutely impacts the digestive and/or respiratory tract of the birds in many species of various orders. More importantly, it is also well known as a significant zoonotic disease, which can lead to diarrhea in humans and livestock. Regarding increasing demand for free-range products and increasing the number of free-range poultry farms, the present paper evaluated histopathological and molecular detection of Cryptosporidium baileyi and Cryptosporidium parvum in free-range and commercial broiler chickens in the north part of Iran. For this purpose, 100 fecal and tissue samples of the chickens in Guilan province were collected. After microscopic examination using Ziehl-Neelsen staining, molecular analyses of the fecal samples were processed by Nested-PCR targeting the 18S rRNA gene followed by sequencing of the amplicons and phylogenetic analyses. Eventually, the tissue samples were studied for histological lesions. Findings demonstrated the presence of Cryptosporidium baileyi and Cryptosporidium parvum in 6 % and 2 % of fecal samples, respectively. This is the first identification of C.parvum in avian hosts in Iran, and for the first time, C.baileyi and C.parvum are shown in native free-range chickens in Iran. All of the PCR positive birds with clinical symptoms showed gross lesions of respiratory infections. There was no significant difference between infection rate in free-range and commercial broiler chickens; however, the infection rate was significantly higher in chickens <25 days old. To conclude, we present here a notable Cryptosporidium infection rate in the free-range chicks in Iran, which notify the role of this host as a reservoir and should be more noted due to the economic and zoonotic importance.     

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.     

Seroprevalence of Toxoplasma gondii in free-ranging wild boars hunted for human consumption in Estonia

Background

Although the prevalence of human Toxoplasma gondii infections is high in Estonia, no information is available on the prevalence of infections in the local animal populations. Wild boars are a good indicator species for estimating the prevalence and spread of T. gondii and were thus investigated in this nationwide cross-sectional study. Volunteer hunters sampled cardiac or skeletal muscle of 471 wild boars legally hunted for human consumption in Estonia during the hunting season of 2012–2013. Serosanguineous meat juice samples were obtained from thawed tissue samples, diluted 1:40, and screened for specific anti-T. gondii IgG antibodies with a commercial direct agglutination test.

Results

Almost one-quarter (113; 24%) of the wild boars examined were seropositive for T. gondii. The seroprevalence did not differ significantly between age groups or sexes. The seroprevalence was lowest in Viljandimaa, which is located in the southern part of Estonia. In other counties, the infection was evenly prevalent.

Conclusions

In Estonia, wild boars are commonly exposed to T. gondii, which is endemic and widespread. The consumption of raw or undercooked meat of Estonian wild boars may pose an infection risk to humans and other hosts.     

Factors affecting seroprevalence of Toxoplasma gondii in the endangered Iberian lynx (Lynx pardinus)

Wild felids are considered important in maintaining the sylvatic cycle of Toxoplasma gondii. Although, T. gondii antibodies have been reported in several species of wild felids, little is known of the epidemiology and risk factors associated with T. gondii infection in wild cats. The Iberian lynx (Lynx pardinus) is the most endangered felid species in the world. In the present study, seroprevalence and associated risk factors for T. gondii infection in a large population of Iberian lynx in Spain were determined. Serum samples from 129 Iberian lynx collected from 2005 to 2009 and 85 wild rabbits (Oryctolagus cuniculus), sharing the habitat with the Iberian lynx, were tested for antibodies to T. gondii by the modified agglutination test (MAT) using a cut-off value of 1:25. Antibodies to T. gondii were found in 81 of 129 (62.8%) Iberian lynx. Seroprevalence to T. gondii in Iberian lynx significantly increased with age (P < 0.001). T. gondii seroprevalences were similar in free-ranging (66.7% of 93) and wild-caught captive lynx (69% of 84) but significantly lower in captive-born lynx (22.5% of 40). Seroprevalence was higher in lynx with concurrent Cytauxzoonfelis (88% of 25) but not with concurrent Feline Leukemia Virus (FeLV) infection (53.8% of 13). There were no significant differences in seroprevalence between sexes, geographic region and year of sample collection (2005–2009). Oocysts of T. gondii were not detected microscopically in fecal samples from 58 lynx. Wild rabbits are considered the most important food for the lynx. Antibodies to T. gondii were found in 14 (11.9%) of 85 rabbits tested. The present results indicate that T. gondii infection is widespread in the two areas where Iberian lynx survive in Spain. The fact that four captive-born lynx seroconverted was indication of contact with T. gondii also in the Captive Breeding Centers, hence, control measures to prevent T. gondii infection would be necessary in these centers.