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

Detection of Toxoplasma gondii Infection in Small Ruminants: Old Problems, and Current Solutions

Toxoplasmosis is a parasitic zoonosis of veterinary importance, with implications for public health. Toxoplasma gondii infection causes abortion or congenital disease in small ruminants. Moreover, the consumption of infected meat, cured meat products, or unpasteurized milk and dairy products can facilitate zoonotic transmission. Serological studies conducted in various European countries have shown the high seroprevalence of specific anti-T. gondii antibodies in sheep and goats related to the presence of oocysts in the environment, as well as climatic conditions. This article presents the current status of the detection possibilities for T. gondii infection in small ruminants and their milk. Serological testing is considered the most practical method for diagnosing toxoplasmosis; therefore, many studies have shown that recombinant antigens as single proteins, mixtures of various antigens, or chimeric proteins can be successfully used as an alternative to Toxoplasma lysate antigens (TLA). Several assays based on DNA amplification have been developed as alternative diagnostic methods, which are especially useful when serodiagnosis is not possible, e.g., the detection of intrauterine T. gondii infection when the fetus is not immunocompetent. These techniques employ multicopy sequences highly conserved among different strains of T. gondii in conventional, nested, competitive, and quantitative reverse transcriptase-PCR.

Seroprevalence and assessment of public awareness of Brucella spp., Toxoplasma gondii and Chlamydia abortus in small ruminants from selected smallholder commercial farms of Zimbabwe

Brucella spp., Toxoplasma gondii, and Chlamydia abortus have long been recognized as zoonoses and significant causes of reproductive failure in small ruminants globally. A cross-sectional study was conducted in August 2020 to determine the seroprevalences of Brucella spp., Toxoplasma gondii and Chlamydia abortus in 398 small ruminants from four districts of Zimbabwe (Chivi, Makoni, Zvimba, and Goromonzi) using Indirect-ELISAs. A structured questionnaire was used to assess the knowledge, attitudes, and practices of 103 smallholder farmers towards small ruminant abortions, Brucella spp., T. gondii and C. abortus, and to obtain a general overview of the significance of small ruminant reproductive failure(s) on their livelihoods. The overall seroprevalences were: 9.1% (95% CI: 6.4-12.3) for Brucella spp., 6.8% (95% CI: 4.5-9.7) for T. gondii and 2.0% (95% CI: 0.9-3.9) for C. abortus. Location, age, parity, and abortion history were associated with Brucella spp. seropositivity. Location was also associated with both T. gondii and C. abortus seropositivity. The questionnaire survey established that 44% of respondents had recently faced reproductive disease challenges within their flocks, with 34% correctly identifying abortion causes and only 10%, 6% and 4% having specific knowledge of Brucella spp., C. abortus and T. gondii, respectively. This study provides the first serological evidence of Brucella spp. in small ruminants since 1996 and builds the evidence on small ruminant toxoplasmosis and chlamydiosis in Zimbabwe. Evidence of these zoonoses in small ruminants and the paucity of knowledge shows the need for a coordinated One Health approach to increase public awareness of these diseases, and to establish effective surveillance and control measures. Further studies are required to establish the role these diseases play in small ruminant reproductive failure(s), to identify the Brucella spp. detected here to species/subspecies level, and to assess the socio-economic impact of reproductive failure in livestock among marginalised rural communities.

Low Prevalence of Toxoplasma gondii in Sheep and Isolation of a Viable Strain from Edible Mutton from Central China

Sheep are highly susceptible to Toxoplasma gondii, and miscarriage is the main clinical feature. This study investigated 227 sheep samples (210 myocardial tissues from slaughterhouses, 6 ewe serum samples, 3 aborted fetuses, and 8 dead lambs from veterinary clinics) from central China for T. gondii infection. Antibodies against T. gondii were detected using the modified agglutination test (MAT). PCR was performed to detect T. gondii DNA in the tissue samples. The results showed that four samples were seropositive (MAT titer ≥ 1:100), with a seroprevalence of 1.8% (4/227). The seropositive samples included two myocardial samples from a slaughterhouse, one ewe and its aborted fetus from a veterinary clinic. The results revealed that 7 out of 207 (3.4%) sheep tissue samples were PCR-positive, including two myocardial tissue samples from slaughterhouses, three aborted fetuses, and two lambs from veterinary clinics. Toxoplasma gondii vertical transmission had occurred in two of three pairs of ewes and her pups. One viable T. gondii strain (TgSheepCHn14) was isolated from the myocardial tissues of sheep from a slaughterhouse. Tachyzoites were obtained from cell cultures at 70 days following seeding in the brains and lungs of mice. This strain was non-lethal to Swiss mice. The number of parasite brain cysts in mice decreased with time post-infection (p < 0.05). Overall, the prevalence of T. gondii in the sheep samples was low. Although the samples were scattered, and not from planned collections, the current study detected T. gondii antibodies and DNA in aborted fetuses, indicating that vertical transmission could occur and maintain the parasites in sheep herds without exogenous infection.

Experimental infection of sheep at mid-pregnancy with archetypal type II and type III Toxoplasma gondii isolates exhibited different phenotypic traits

Toxoplasma gondii is a major cause of reproductive failure in small ruminants. Genotypic diversity of T. gondii strains has been associated with variations in phenotypic traits in in vitro and murine models. However, whether such diversity could influence the outcome of infection in small ruminants remains mostly unexplored. Here, we investigate the outcome of oral challenge in sheep at mid-pregnancy with 10 sporulated oocysts from three different T. gondii isolates belonging to archetypal II and III and selected according to their genetic and phenotypic variations shown in previous studies. Seventy-three pregnant sheep were divided in four groups: G1 infected with TgShSp1 isolate (type II, ToxoDB#3), G2 with TgShSp16 isolate (type II, ToxoDB#3), G3 with TgShSp24 isolate (type III, ToxoDB#2) and G4 of uninfected control sheep. Two different approaches were carried out within this study: (i) the outcome for the pregnancy after infection (n = 33) and (ii) the lesions and parasite tropism and burden at 14 and 28 days post infection (dpi) (n = 40). The onset of hyperthermia and seroconversion occurred one and two days later, respectively in G1 when compared to G2 and G3. However, sheep that suffered from reproductive failure, either by abortion, foetal dead at the time of euthanasia or stillbirth were similar among infected groups (50%, 40% and 47%, respectively). Histological lesions in placentomes and foetal tissues from euthanized animals from the second approach were only detected at 28 dpi and mainly in G1. At 14 dpi, T. gondii-DNA was only detected in G1 in the 11% of the placentomes. However, at 28 dpi the frequency of detection in placentomes was higher in G1 (96%) than in G2 and G3 (7% and 47%, respectively) besides in foetuses was lower in G2 (20%) than in G1 and G3 (100% and 87%, respectively). Regarding late abortions, stillbirths, and lambs of G1, G2 and G3, the frequency of microscopic lesions was similar between groups (79%, 78% and 67%, respectively) whereas T. gondii-DNA was evidenced in 100%, 55% and 100%, respectively. These recently obtained T. gondii isolates led to similar reproductive losses but intra- and inter-genotype variations in the rise of hyperthermia, dynamics of antibodies, frequency of lesions and parasite detection and distribution. Thus, the different phenotypic traits of the isolates could influence the outcome of the infection and mechanisms responsible for it, and further investigations are warranted.

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

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

Evaluation of anti-parasitic activities of new quinolones containing nitrofuran moiety against Toxoplasma gondii

Toxoplasmosis is a disease with a worldwide prevalence that is caused by Toxoplasma gondii. Pyrimethamine and sulfadiazine are two pharmacological agents commonly used to treat of this infection. However, they are accompanied by some side effects. Therefore, the identifying of new drugs with low toxocytosis seems to be a matter of vital importance. Quinolones are DNA replication inhibitors, exerting inhibitory effects against many pathogens, including bacteria, mycoplasma, and protozoa. Given the importance of quinolones and their efficacy, the present in vitro study was conducted to investigate the antiparasitic activities of new quinolones (NFQ-2, NFQ-5, and NFQ-6) containing nitrofuran moiety against T. gondii. To this end, Vero cells were incubated with various concentrations of new quinolones and pyrimethamine (positive control) to determine their viability. Subsequently, they were infected with T. gondii (RH strain) and then subjected to drug treatment. The obtained IC₅₀ values were 3.60, 4.84, 5.59, 3.44 and 2.75 μg/mL for NFQ-2, NFQ-5, NFQ-6, ciprofloxacin and pyrimethamine, respectively. The CC₅₀ values for the NFQ-2, NFQ-5, and NFQ-6 were 25.20, 29.89, and 28.43 μg/mL, indicating the selectivity indexes more than 5 for these compounds. The anti-Toxoplasma efficiency was determined by evaluating infection index, number and size of plaques, and T. gondii intracellular proliferation. As the results indicated, the administration of new quinolone derivatives resulted in the reduction of intracellular proliferation, infection index, and the number and size of plaques in comparison to uninfected treated cells (P < 0.05). The results were indicative of a considerable synergetic effect when each of the derivatives was used in combination with pyrimethamine, compared to when used alone. Based on our results, the nitrofuran-derived quinolones can be considered as new leads for the design of new anti-Toxoplasma agents.

Serological Investigation of Bovine Toxoplasmosis Using Commercial and Indigenous ELISA Kits While Validating Cattle Toxo IgG ELISA Kit

Simple Summary

Toxoplasmosis is a zoonotic disease caused by T. gondii infection. The main aims of this study were to assess the seropositivity to toxoplasmosis of an exotic breed of cattle (n = 400) from different farms using the Latex Agglutination Test, validate the Cattle Toxo IgG ELISA kit with the help of the commercially available ELISA kit and compare the efficacy of the LAT and Cattle Toxo IgG ELISA kit for assessing seropositivity of cattle to toxoplasmosis. Four hundred cattle sera were collected from an exotic breed of cattle in Pakistan. These sera were evaluated through an LAT and Cattle Toxo IgG ELISA kit. Of 400 samples, 90 were elected and screened through a commercially available ELISA kit. The sensitivity and specificity of the Cattle Toxo IgG ELISA kit came out to be 100% and 96.15%, and in LAT, it was found as 26.31% and 61.53%, respectively. The Cattle Toxo IgG ELISA kit revealed 29.75% (119/400) seropositivity, 6% less than that found through LAT. The results of this study show that Cattle Toxo IgG ELISA kit is a highly accurate and reliable serodiagnostic tool to diagnose bovine toxoplasmosis.

Abstract

Toxoplasma gondii is a protozoan parasite that causes toxoplasmosis in warm-blooded vertebrates, globally. The main aims of this study were to assess the seropositivity to toxoplasmosis of an exotic breed of cattle (n = 400) from different farms using the Latex Agglutination Test and validate Cattle Toxo IgG ELISA kit. Of a total of 400 cattle sera that were evaluated by LAT, 143 (35.75%) were found positive. Based on these data, 90 samples (n = 60 seronegative by LAT; n = 30 seropositive by LAT) were elected for screening through a commercially available ELISA kit. The same 90 samples were screened through a Cattle Toxo IgG ELISA kit for validation purposes. Of 90 samples, 40 were seropositive in the Cattle Toxo IgG ELISA kit (100% sensitivity), and 38 were seropositive in a commercially available ELISA kit. All 50 samples in the Cattle Toxo IgG ELISA kit (96.15% specificity) were also seronegative in the commercially available ELISA kit. Hence, the sensitivity and specificity of the Cattle Toxo IgG ELISA kit came out to be 100% and 96.15%, and in LAT, it was found as 26.31% and 61.53%, respectively. Therefore, the Cattle Toxo IgG ELISA kit is a highly reliable serodiagnostic tool to diagnose bovine toxoplasmosis.

Toxoplasma gondii in African Wildlife: A Systematic Review

Toxoplasma gondii (T. gondii) is a protozoan parasite, which infects a wide variety of mammals and bird species globally. In large parts of the world, this parasite is relatively well documented in wildlife species, however, this topic is poorly documented in Africa. The current review systematically explores the presence and distribution of T. gondii in African wildlife species through a key word search in PubMed, Web of Science and CAB Direct. A total of 66 records were identified and included in the qualitative analysis, of which 19 records were retained for the quantitative synthesis. The presence of T. gondii was reported in a wide range of wildlife species, found in twelve countries, spread over the African continent. The retained records report a prevalence range of 6–100% in herbivores, 8–100% in omnivores and 14–100% in carnivores. In wild felines (cheetahs, leopards, and lions) a prevalence range of 33–100% was found. Reports from South Africa, and on the presence of T. gondii in lion were most common. Overall, the results indicate the scarcity of information on T. gondii in Africa and its circulation in wildlife. The lack of knowledge on the parasite in Africa, especially in areas at the human-livestock-wildlife interface, prevents us from understanding how prevalent it is on the continent, what strains are circulating in wildlife and what the most common routes of transmission are in the different habitats in Africa.

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

The aim of this work was to identify causes of abortion through laboratory investigations in sheep flocks in Uruguay. One hundred cases of abortion, comprising 58 fetuses, 36 fetuses with their placentas, and 6 placentas were investigated in 2015–2021. Cases were subjected to gross and microscopic pathologic examinations, and microbiological and serological testing for the identification of causes of abortion, including protozoal, bacterial, and viral pathogens. An etiologic diagnosis was determined in 46 (46%) cases, including 33 (33%) cases caused by infectious pathogens, as determined by the detection of a pathogen along with the identification of fetoplacental lesions attributable to the detected pathogen. Twenty-seven cases (27%) were caused by Toxoplasma gondii, 5 (5%) by Campylobacter fetus subspecies fetus, and 1 (1%) by an unidentified species of Campylobacter. Fourteen cases (14%) had inflammatory and/or necrotizing fetoplacental lesions compatible with an infectious etiology. Although the cause for these lesions was not clearly identified, T. gondii was detected in 4 of these cases, opportunistic bacteria (Bacillus licheniformis, Streptococcus sp.) were isolated in 2 cases, and bovine viral diarrhea virus 1 subtype i (BVDV-1i) was detected in another. Campylobacter jejuni was identified in 1 (1%) severely autolyzed, mummified fetus. BVDV-2b was identified incidentally in one fetus with an etiologic diagnosis of toxoplasmosis. Microscopic agglutination test revealed antibodies against ≥1 Leptospira serovars in 15/63 (23.8%) fetuses; however, Leptospira was not identified by a combination of qPCR, culture, fluorescent antibody testing nor immunohistochemistry. Neospora caninum, Chlamydia abortus, Chlamydia pecorum, Coxiella burnetii and border disease virus were not detected in any of the analyzed cases. Death was attributed to dystocia in 13 (13%) fetuses delivered by 8 sheep, mostly from one highly prolific flock. Congenital malformations including inferior prognathism, a focal hepatic cyst, and enterohepatic agenesis were identified in one fetus each, the latter being the only one considered incompatible with postnatal life. Toxoplasmosis, campylobacteriosis and dystocia were the main identified causes of fetal losses. Despite the relatively low overall success rate in establishing an etiologic diagnosis, a systematic laboratory workup in cases of abortion is of value to identify their causes and enables zoonotic pathogens surveillance.

Neospora caninum and Toxoplasma gondii as causes of reproductive losses in commercial sheep flocks from Argentina

The aim of this study is to provide preliminary data about the occurrence of Neospora caninum- and Toxoplasma gondii-related abortions and perinatal deaths in sheep from Argentina. Thirty ovine aborted foetuses and 33 perinatal deaths were submitted to the Veterinary Diagnostic Service at INTA EEA Balcarce (Argentina) during 2017–2019. A complete necropsy was performed on all specimens submitted, and foetal and placental tissues were examined. Foetal cavity fluids were collected for assessment of antibodies to N. caninum and T. gondii by indirect fluorescent antibody technique (IFAT). Placental and foetal tissue samples were collected for DNA extraction and histopathological analysis. The differential diagnosis with other causes of abortion was carried out. Of the sampled specimens, 20.63% (13/63) displayed evidence for N. caninum infection by IFAT and PCR, and in 61.5% (8/13) of the positive specimens the parasite was confirmed as the cause of abortion/perinatal death based on the presence of compatible histological lesions and/or positive immunohistochemistry test, positive PCR and/or positive IFAT, and no other infectious agents diagnosed. In contrast, T. gondii infection was confirmed in 9.52% (6/63) of the analysed specimens, but only in 2 lambs T. gondii was determined as the death cause. Neosporacaninum and T. gondii co-infections were confirmed in 4 analysed specimens (2 aborted foetuses and 2 perinatal deaths). These results demonstrated that N. caninum is efficiently transmitted and a frequent cause of ovine reproductive failure in the commercial analysed flocks compared with T. gondii. Despite T. gondii congenital infection was detected in some specimens (6/63), it was confirmed as the cause of death in only two of them. Thus, and considering the limited availability of confirmed samples, we could not determine whether toxoplasmosis is a major problem in Argentinian sheep flocks or not. More studies on a greater number of specimens from different ovine production systems under different management conditions are necessary to assess the real impact of neosporosis and toxoplasmosis in Argentina.

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Neospora caninum congenital infection was found in 13 of the 63 analysed specimens.

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In 8 of these 13 cases, N. caninum was confirmed as the cause of abortion/perinatal death.

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Toxoplasma gondii was determined as the perinatal death cause in 2 lambs.

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Co-infections with N. caninum + T. gondii were only confirmed in 4 analysed specimens.

Anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs

Consumption of raw or undercooked meat containing Toxoplasma gondii tissue cysts is one of the main sources of infection for humans worldwide. Among the various species intended for human consumption, sheep appear to be a high risk for human infection. The present study focused on the detailed anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs using fresh and frozen samples of various pieces of meat, from a public health perspective. The first objective was to rank the edible parts intended for human consumption according to the detectable parasite burden by real-time PCR targeting the 529-bp repeated element. The second objective was to evaluate the impact of freezing by comparing the detection efficiency of the quantitative PCR between fresh and frozen tissues, as imports of lamb carcasses/cuts may arrive frozen or chilled. The highest estimated parasite loads were observed in skeletal muscles, and more particularly in edible portions such as quadriceps femoris muscle, intercostal muscles, deltoid muscle and diaphragm, with a significant difference in detectable parasite burden between fresh and frozen samples (p < 0.0001) or natural and experimental infection (p < 0.0001). Thoracic and pelvic limbs (3278-1048 parasites/g muscle) were ranked at the top of the list. Toxoplasma gondii DNA was detected in all the edible parts of lamb studied. These results suggest that lamb meat represents a risk for consumers. Further investigations are needed in order to confirm these differences in larger numbers of animals and in different breeds.

Investigation of Toxoplasma gondii and Neospora caninum as cause of ovine abortion in affected flocks of Urmia, northwest of Iran

Toxoplasma gondii and Neospora caninum, two obligatory intracellular protozoan parasites, are important causes of neonatal mortality and abortion in farmed ruminants worldwide. Previously, protozoan abortions in small ruminants were attributed to T. gondii, but the role of N. caninum in these abortions was uncertain. The aim of this study was to investigate the role of T. gondii and N. caninum in ovine abortion in Urmia, northwest of Iran using a molecular method. Overall, 130 placenta and brain samples of aborted ovine foetuses were collected. Extracted DNA from placenta and CNS tissues of the aborted foetuses were analysed using PCR with primers specific for T. gondii and N. cani­num. The association of the frequency of T. gondii and N. caninum infection of aborted foetuses with age and breed in flocks was also studied. The results showed that out of the 130 examined ovine foetuses, 5.3 and 2.3 % were PCR-positive for T. gondii and N. caninum DNA, respectively. In this study, no significant differences were recorded relating to Toxoplasma and Neospora infection in different age groups in flocks and among sheep breeds included in the present study (P>0.05). The results of this study proved the importance of T. gondii and N. caninum as reasons of abortion in the studied area.

Seroprevalence and molecular characterization of Toxoplasma gondii infecting ruminants in the North-West of Egypt

Toxoplasma gondii is a coccidian parasite known for its heavy toll on people and livestock. It can cause abortion and a variety of congenital diseases. The current study aimed to examine some seroprevalence and molecular attributes of T. gondii obtained from ruminants in the North-West of Egypt. Specimens were random selected from five different locations in Alexandria and Matrouh governorates. A total of 483 blood samples, collected from 96 mixed flocks, were screened for anti-T. gondii IgG antibodies using enzyme-linked immunosorbent assay (ELISA). The seropositive results were then confirmed using polymerase chain reaction (PCR) primers for the B1 and P30 genes. Specific PCR products were selected for sequencing and alignment against the GenBank, where phylogeny has been examined using the maximum likelihood, neighbor-joining, and maximum parsimony in MEGA6. ELISA confirmed the presence of T. gondii in 188 of the investigated samples (38.92%), indicating a higher prevalence in camels (64.51%) and sheep (43.75%) as compared to goats (27.93 %) and cattle (13.46%). PCR confirmed the presence of T. gondii-specific sequences in 159 seropositive specimens, with homology between 98.3 and 100%. The genetic distances between the investigated variants ranged from 0.1 to 0.9, and 7 single nucleotide polymorphisms (SNPs), were identified in the examined T. gondii specimens. The camel T. gondii parasite, isolated from Matrouh, showed a 100% homology with the most dangerous reference strains of T. gondii-RH in the GenBank. Our results showed that B1 and P30-specific PCR could detect T. gondii in blood samples more accurately than ELISA. In addition, the statistical analysis of our data indicated that species, age, sex, and animal location were all risk factors for toxoplasmosis. These findings are likely to boost disease control and help contain the spread of T. gondii infections.

High level of infection by Toxoplasma gondii in pigs slaughtered in the city of São Luís, Maranhão

A serological, molecular and histopathological study was carried out in order to investigate occurrences of Toxoplasma gondii in pigs slaughtered with and without inspection service. Serum samples were collected from 60 pigs to detect anti-T. gondii antibody by indirect fluorescent antibody (IFAT). Tongue, masseter and diaphragm fragments were also collected for parasite DNA detection by means of the polymerase chain reaction (PCR) and histopathological analysis. The serological results showed that 77% (44/60) of the pigs were positive. Regarding PCR, 66.67% (40/60) were positive for T. gondii. Among the tissues evaluated, the diaphragm was the one with the highest frequency of positivity (40%; 24/60), followed by the masseter (38.33%; 23/60) and tongue (33.3%; 20/60). Histopathological changes were only observed in the diaphragm, which presented inflammatory infiltrates of lymphohistiocytic and neutrophilic types. These results not only show the potential threat of T. gondii to human health, but also demonstrate the dynamic epidemiological situation of toxoplasmosis in pigs in the city of São Luís, providing support for food security regarding pigs and for T. gondii control programs in Brazil.

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

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

Descriptive Comparison of ELISAs for the Detection of Toxoplasma gondii Antibodies in Animals: A Systematic Review

Toxoplasma gondii is the zoonotic parasite responsible for toxoplasmosis in warm-blooded vertebrates. This systematic review compares and evaluates the available knowledge on enzyme-linked immunosorbent assays (ELISAs), their components, and performance in detecting T. gondii antibodies in animals. Four databases were searched for published scientific studies on T. gondii and ELISA, and 57 articles were included. Overall, indirect (95%) and in-house (67%) ELISAs were the most used types of test among the studies examined, but the 'ID Screen® Toxoplasmosis Indirect Multi-species' was common among commercially available tests. Varying diagnostic performance (sensitivity and specificity) and Kappa agreements were observed depending on the type of sample (serum, meat juice, milk), antigen (native, recombinant, chimeric) and antibody-binding reagents used. Combinations of recombinant and chimeric antigens resulted in better performance than native or single recombinant antigens. Protein A/G appeared to be useful in detecting IgG antibodies in a wide range of animal species due to its non-species-specific binding. One study reported cross-reactivity, with Hammondia hammondi and Eimeria spp. This is the first systematic review to descriptively compare ELISAs for the detection of T. gondii antibodies across different animal species.

Anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from Paraná state, South Brazil: prevalence and associated factors

The aim of this study was to evaluate the seroprevalence and factors associated with the presence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from Paraná state. The detection of antibodies for T. gondii and N. caninum was performed by homemade and commercial indirect ELISA, respectively. Multiple logistic regression analysis was used to verify the factors associated with the seroprevalence. Antibodies anti-T. gondii and anti-N. caninum were observed in 42.7% and in 17.6% of the animals, respectively. The protective factors associated to seropositive were "some level of confinement" (full or semi-extensive confinement) (OR=0.53) for T. gondii and "use of skilled labor" (OR=0.64) for N. caninum. The risk factors were "presence of cats" (OR=1.75) for T. gondii and "feeding of dogs with sheep placental remains" (OR=1.79) for N. caninum. In addition, to presenting a significant and simultaneous seroprevalence for both agents (9.9% of the animals), the results also indicate that deficiencies in management and environmental sanitation, the presence of reservoirs, and types of exploitation enhance the seropositivity. Thus, studies like this might support sanitary programs and public policies for the prevention of T. gondii and N. caninum in the sheep herds of Paraná state.

Global prevalence of Toxoplasma gondii infection in the aborted fetuses and ruminants that had an abortion: A systematic review and meta-analysis

Toxoplasma gondii (T. gondii) is a zoonotic apicomplexan protozoan that can cause reproductive losses in ruminants across the world. Therefore, a meta-analysis was conducted to estimate the worldwide prevalence of T. gondii infection in the aborted fetuses and stillbirths of sheep, goat, and cattle. Moreover, it attempted to evaluate the prevalence rate of T. gondii infection in ruminants that had abortions using serological methods. Based on the keywords, a systematic search of six databases was conducted to retrieve cross-sectional articles in English-language. Data were synthesized to calculate the overall prevalence of T. gondii infection worldwide using the random-effects model with a 95 % confidence interval (CI). Moreover, the present study includes sensitivity analysis, publication bias test, and quality assessment of the studies. The final analyses included 37, 19, and 8 studies conducted on sheep (4383 aborted fetuses and stillbirths as well as 1940 abortive sheep), goat (248 aborted fetuses and stillbirths and 533 abortive goats), and cattle (460 aborted fetuses and stillbirths and 165 abortive cattle). The overall prevalence rates of T. gondii infection in aborted fetuses and stillbirths globally were 42 % (95 % CI: 17 %-67 %), and 31 % (95 % CI: 11 %-51 %) using molecular methods for sheep and goats, as well as 16 % (95 % CI: 11 %-22 %) and 27 % (95 % CI: 1 %-54 %) using serological tests for sheep and goats, respectively. In addition, the overall prevalence rates of T. gondii infection in sheep and goats that had abortions were 56 % (95 % CI: 35 %-76 %) and 50 % (95 % CI: 6 %-94 %), respectively. These analyses could not be performed in cattle due to the small number of studies and the small number of animals under study. According to the high prevalence of T. gondii infection in sheep and goats that had an abortion, T. gondii could be a potential factor of causing reproductive failures in ruminants worldwide. So, effective control measures and strategies are needed to reduce the rate of abortion in sheep and goats as well as reduce the economic damage to the livestock industry.

Effect of Toxoplasma gondii on Ram Sperm Quality After Experimental Infection

The aim of this study was to investigate the effect of experimental Toxoplasma gondii infection on ram sperm quality. Five months old, pre-pubertal, rams were divided into four groups (n = 8 per group). Group A was the control group; the remaining animals received per os (p.o.) 5000 oocysts per ram. Group B did not receive treatment post-infection (p.i.). Group C received sulphadimidine (intermuscular injection (i.m.) 33 mg/kg for eight days; every 48 hrs) two months p.i. and Group D received the same drug twice (24 hours p.i. and two months later). Blood samples were collected every 15 days to detect serum immunoglobulin G (IgG). Epididymal sperm samples were analyzed for concentration, kinetics, morphology/viability, functional membrane integrity, DNA integrity, and the presence of parasite DNA. Histopathological examination was performed on the testes. The IgG titres in infected groups raised two weeks p.i. and remained high for four months. Higher values were noticed in viability and functional membrane integrity in positive spermatozoa in the control group compared to other groups, level of significance p < 0.05. Abnormal sperm was higher in groups C and D vs. A and C vs. B (p < 0.05). T. gondii DNA was detected in three sperm samples of the infected rams (12.5%). Histopathology revealed similar findings with little variation among all infected groups, characterized mostly by increased interstitial connective tissue, non-purulent inflammation, and presence of seminiferous tubules with spermatogenic cell depletion, which increased gradually from D to C and B groups. In conclusion Toxoplasmosis in pre-pubertal age negatively affected mature ram sperm quality, while sulphadimidine administration failed to alter this.

Foodborne transmission of Toxoplasma gondii infection in the last decade. An overview

Toxoplasmosis is a zoonotic disease of global distribution and importance. It is caused by the protozoan parasite Toxoplasma gondii, the only species in the Toxoplasma genus. This parasite can infect most warm-blooded animals, including humans and livestock. Main routes of transmission are by ingestion of tissue cysts in raw or undercooked meat of infected animals, ingestion of raw vegetables or water contaminated with T. gondii oocysts from cat feces, and transplacental. Around one-third of human beings are chronically infected with T. gondii. Most infections appear to be asymptomatic in immunocompetent persons, but toxoplasmosis can be fatal to the fetus and immunocompromised adults. Water and foodborne outbreaks have been caused by this parasite worldwide, but few are well documented. Importantly, T. gondii is a parasite of high importance in animal health, causing reproductive failure, particularly in small ruminants, and clinical toxoplasmosis in many species. This overview discusses the knowledge of T. gondii infections in the last decade focusing on the foodborne transmission of this parasite.

Comparative aspects of laboratory testing for the detection of Toxoplasma gondii and its differentiation from Neospora caninum as the etiologic agent of ovine abortion

Histologic examination of aborted material is an essential component in the diagnosis of ovine toxoplasmosis. However, the detection of Toxoplasma gondii in histologic sections, and its differentiation from the closely related protozoan Neospora caninum, is challenging. We developed a chromogenic in situ hybridization (ISH) assay for the identification of T. gondii in paraffin-embedded tissue samples. We examined retrospectively the archived placental tissue of 200 sheep abortion submissions for the presence of T. gondii by immunohistochemistry (IHC), ISH, and real-time PCR (rtPCR). All placental samples that tested positive for T. gondii by rtPCR (9 of 200) were also positive by IHC, with inconclusive IHC staining in an additional 7 rtPCR-negative cases. Further testing for N. caninum of all 200 placentas by rtPCR revealed 7 Neospora-positive cases. T. gondii ISH was positive in 4 of 9 IHC-positive samples and 1 of the 7 N. caninum rtPCR-positive samples. Real-time PCR was used as the reference standard for specificity and sensitivity calculations regarding placenta samples. Specificity of ISH and IHC was 99% and 96-100%, respectively. The sensitivity of ISH (44%) was quite low compared to IHC (100%). The exclusive use of ISH for the detection of T. gondii, and thus for the diagnosis of ovine toxoplasmosis, was not acceptable. However, combined with rtPCR, both ISH and IHC can be useful detection methods to improve histologic evaluation by visualizing the parasite within tissue sections.

Toxoplasma gondii in small ruminants in northeastern areas of Colombia: Seroprevalence and risk factors

Sheep and goats are susceptible to infections with Toxoplasma gondii and could play an important role in the transmission of the zoonotic parasite to human. We conducted a cross sectional study to estimate the seroprevalence and to assess the risk factors for T. gondii seropositivity in small ruminants under traditional husbandry systems. This study was carried out from November 2015 to April 2016 in randomly selected small ruminants (n = 1038) from 48 farms located in Colombia, in the departments of northern Cesar in the north and La Guajira in the south. An indirect ELISA was used to detect IgG antibodies to T. gondii in the animals. A standardized questionnaire was used to obtain information on putative risk factors. We conducted the association analyses by using univariable and multivariate logistic regression and report odds ratios (OR) with 95% confidence interval (C.I). The overall seroprevalence in small ruminants was 23.5% (C.I: 21–26.2%). Sheep showed a higher seroprevalence (25.1% C.I: 22.4–28.6%) than goats (18.4% C.I: 22.4–28.6%). The association analysis recognized as risk factors for T. gondii seropositivity farming pigs in addition to small ruminants (OR = 1.96 C.I: 1.414–2.743), the inexistence of manure heap (OR = 2.254 C.I: 1.480–3.433) and drinking water from locally aqueducts (OR = 1.489 C.I: 1.006–2.204). The results of the study confirmed that exposure to T. gondii is common in sheep and goats in dry Caribbean regions of Colombia.

Toxoplasma gondii Tetravalent Chimeric Proteins as Novel Antigens for Detection of Specific Immunoglobulin G in Sera of Small Ruminants

Simple Summary

Toxoplasma gondii infection leads to large economic losses in the sheep and goat industry worldwide and is considered to be one of the main causes of infectious ovine and caprine abortion. Moreover, in countries where sheep and goat meat are frequently consumed, T. gondii infection in small ruminants may also pose a public health risk. Due to its medical and veterinary importance, it is essential to study the seroprevalence of T. gondii infection among farm animals and humans. This requires the development of new, low-cost diagnostic methods such as enzyme immunoassays based on recombination antigens. Thus, the study aimed to evaluate the reactivity of four different tetravalent chimeric proteins containing immunodominant regions from the AMA1 (apical membrane antigen 1), SAG2 (surface antigen 2), GRA1 (dense granule antigen 1), GRA2 (dense granule antigen 2), and ROP1 (rhoptry antigen 1) T. gondii antigens with specific IgG from the sera of small ruminants. The results demonstrate that an IgG ELISA (enzyme-linked immunosorbent assay) based on one of these chimeric proteins (AMA1-SAG2-GRA1-ROP1) may be a useful test for the determination of T. gondii infection in small ruminants.

Abstract

The detection of Toxoplasma gondii infection in small ruminants has important significance for public health and veterinary medicine. This study, for the first time, describes the reactivity of four tetravalent chimeric proteins (AMA1_N-SAG2-GRA1-ROP1, AMA1_C-SAG2-GRA1-ROP1, AMA1-SAG2-GRA1-ROP1, and SAG2-GRA1-ROP1-GRA2) containing immunodominant regions from the AMA1 (apical membrane antigen 1), SAG2 (surface antigen 2), GRA1 (dense granule antigen 1), GRA2 (dense granule antigen 2), and ROP1 (rhoptry antigen 1) with specific IgG antibodies from the sera of small ruminants with the use of an indirect enzyme-linked immunosorbent assay (ELISA). The reactivity of individual chimeric antigens was analyzed in relation to the results obtained in IgG ELISA based on a Toxoplasma lysate antigen (TLA). All chimeric proteins were characterized by high specificity (between 96.39% to 100%), whereas the sensitivity of the IgG ELISAs was variable (between 78.49% and 96.77%). The highest sensitivity was observed in the IgG ELISA test based on the AMA1-SAG2-GRA1-ROP1. These data demonstrate that this chimeric protein can be a promising serodiagnostic tool for T. gondii infection in small ruminants.

Liver fluke in Irish sheep: prevalence and associations with management practices and co-infection with rumen fluke

BACKGROUND

The present study aimed to identify the national prevalence of Fasciola hepatica in Irish sheep and to conduct a risk analysis assessment based on management and treatment practices in participating flocks. Also, co-infection with rumen fluke was quantified and its association with liver fluke and management practices was assessed.

METHODS

A total of 305 sheep flocks were selected ensuring even national representation of the sheep population. Participating farms were asked to complete a survey questionnaire on farm management practices and submit faecal samples during the winter of 2014-2015. Pooled faecal samples were analysed for the presence of F. hepatica and co-infection with rumen fluke. Apparent and true prevalence were calculated, additionally, the rate of co-infection with rumen fluke was also obtained. Correlation and regression analyses were used for assessing associations between management practices, liver fluke infection and co-infection with rumen fluke.

RESULTS

The national true prevalence of F. hepatica was 50.4% (n = 305). Regional prevalence varied from 41% in the east to 52% in the south. Co-infection with rumen fluke was observed in 40% of the studied population and correlated with increased F. hepatica egg counts (OR = 2.9; P ≤ 0.001). Predominant breeds were Suffolk, Texel and Horned Mountain breeds. Beef cattle were the most frequent type of other livestock present on farms and mixed species grazing was frequently reported (73%). More than half of the flocks reported a mid-to-late lambing period (March-April). Use of mountain land for grazing was of 32%. Flukicides were most commonly used twice over the autumn-winter period. Regression analyses highlighted significant association of F. hepatica status, with the presence of other livestock on farm, frequency of flukicides used during the winter and clinical presentation of liver fluke. A significant increase in eggs per gram of faeces was observed in Charollais sheep in comparison with all other breeds. Co-infection with F. hepatica and Calicophoron daubneyi was also significantly associated with the presence of other livestock on the farm, type of flukicide used and clinical fasciolosis.

CONCLUSIONS

The present study provides up-to-date information on the prevalence of F. hepatica in Irish sheep and adds insight to the epidemiology of the disease. These findings will be useful for designing new holistic control measures for F. hepatica infection.

Using lamb sales data to investigate associations between implementation of disease preventive practices and sheep flock performance

Although the UK is the largest lamb meat producer in Europe, there are limited data available on sheep flock performance and on how sheep farmers manage their flocks. The aims of this study were to gather evidence on the types of disease control practices implemented in sheep flocks, and to explore husbandry factors associated with flock productivity. A questionnaire focusing on farm characteristics, general husbandry and flock health management was carried out in 648 farms located in the UK over summer 2016. Abattoir sales data (lamb sales over 12 months) was compared with the number of breeding ewes on farm to estimate flock productivity (number of lambs sold for meat per 100 ewes per farm per year). Results of a multivariable linear regression model, conducted on 615 farms with complete data, indicated that farms vaccinating ewes against abortion and clostridial agents and administering a group 4/5 anthelmintic to ewes (as recommended by the Sustainable Control of Parasites in Sheep Initiative) during quarantining had a greater flock productivity than farms not implementing these actions (P<0.01 and 0.02, respectively). Flocks with maternal breed types had higher productivity indexes compared with flocks with either pure hill or terminal breeds (P<0.01). Farms weighing lambs during lactation had greater productivity than those not weighing (P<0.01). Importantly, these actions were associated with other disease control practices, for example, treating individual lame ewes with an antibiotic injection, weaning lambs between 13 and 15 weeks of age and carrying out faecal egg counts, suggesting that an increase in productivity may be associated with the combined effect of these factors. This study provides new evidence on the positive relationship between sheep flock performance and disease control measures and demonstrates that lamb sales data can be used as a baseline source of information on flock performance and for farm benchmarking. Further research is needed to explore additional drivers of flock performance.

Seroprevalence and factors associated with bovine and swine toxoplasmosis in Bobo-Dioulasso, Burkina Faso

Background and Aim:

Toxoplasmosis is a worldwide zoonosis with major public health importance. To know more about this condition in Burkina Faso, this study was implemented to determine the seroprevalence of Toxoplasma gondii infection among pigs and cattle in intra-urban and peri-urban area of Bobo-Dioulasso (Burkina Faso).

Materials and Methods:

Serum samples were collected from 600 cattle and 600 pigs with 300 samples from each species in intra-urban and peri-urban area of Bobo-Dioulasso. Data about age, sex, and breed of each animal were also noted. Serum samples were analyzed by indirect enzyme-linked immunosorbent assay to look for immunoglobulin G and immunoglobulin M antibodies to T. gondii.

Results:

This study revealed a herd prevalence of 92.5% and 75%, respectively for porcine and bovine toxoplasmosis. At the individual level, we found a prevalence of 29% and 49.2% for cattle and pigs, respectively. For each species, we noticed a significant association between age, sex, breed husbandry system, and the presence of anti-T. gondii antibodies. The prevalence was significantly higher in female, intra-urban system, exotic breed, and animal <2 years old (p<0.05)

Conclusions:

The results provided evidence for the presence of T. gondii in pigs and cattle farms around Bobo-Dioulasso. Hence, in Bobo-Dioulasso, raw or undercooked meat consumption is a risk for T. gondii infection for human. Knowledge of the prevalence of toxoplasmosis will help to target prevention efforts.

Treatment with Bumped Kinase Inhibitor 1294 Is Safe and Leads to Significant Protection against Abortion and Vertical Transmission in Sheep Experimentally Infected with Toxoplasma gondii during Pregnancy

Previous studies on drug efficacy showed low protection against abortion and vertical transmission of Toxoplasma gondii in pregnant sheep. Bumped kinase inhibitors (BKIs), which are ATP-competitive inhibitors of calcium-dependent protein kinase 1 (CDPK1), were shown to be highly efficacious against several apicomplexan parasites in vitro and in laboratory animal models. Here, we present the safety and efficacy of BKI-1294 treatment (dosed orally at 100 mg/kg of body weight 5 times every 48 h) initiated 48 h after oral infection of sheep at midpregnancy with 1,000 TgShSp1 oocysts. BKI-1294 demonstrated systemic exposure in pregnant ewes, with maximum plasma concentrations of 2 to 3 μM and trough concentrations of 0.4 μM at 48 h after each dose. Oral administration of BKI-1294 in uninfected sheep at midpregnancy was deemed safe, since there were no changes in behavior, fecal consistency, rectal temperatures, hematological and biochemical parameters, or fetal mortality/morbidity. In ewes infected with a T. gondii oocyst dose lethal for fetuses, BKI-1294 treatment led to a minor rectal temperature increase after infection and a decrease in fetal/lamb mortality of 71%. None of the lambs born alive in the treated group exhibited congenital encephalitis lesions, and vertical transmission was prevented in 53% of them. BKI-1294 treatment during infection led to strong interferon gamma production after cell stimulation in vitro and a low humoral immune response to soluble tachyzoite antigens but high levels of anti-SAG1 antibodies. The results demonstrate a proof of concept for the therapeutic use of BKI-1294 to protect ovine fetuses from T. gondii infection during pregnancy.

Serological survey for anti-Toxoplasma gondii antibodies in sheep of northeastern Algeria

Although T. gondii is of considerable both public and veterinary importance worldwide, studies on its existence in sheep in Algeria, either through serology and or parasitology is scarce. To this end, a cross-sectional study was carried out in Tébessa, an Algerian eastern province, to, firstly, investigate the seroprevalence of T. gondii infection in sheep and, secondly, determine the potential risk factors that may be associated with seropositivity. A total of 376 serum samples from 39 flocks, collected between September 2015 and October 2017, were tested for anti-T.gondii antibodies via the enzyme-linked immunosorbent assay technique (ELISA). A T. gondii seroprevalence of 35.37% (95% CI 30.54-40.21%) was recorded, and 84.61% (95% CI 73.29-95.94%) of the flocks sampled had, at least, one seropositive animal. The multivariable logistic regression analysis showed that abortion during the latest pregnancy (OR = 1.56; 95% CI 1.02-2.44; p = 0.05), presence of goats in sheep flocks (OR = 1.76; 95% CI 1.04-2.98; p = 0.037), and the sampling period were the variables significantly associated with seropositivity. The present study reports, for the first time in this part of Algeria, the seroprevalence of T. gondii infection and bears out the highly dissemination capacity of the parasite. This is of a great importance for veterinarians in charge of veterinary public health, veterinary practitioners, and breeders in order to improve the control and prophylactic measures of toxoplasmosis. Nevertheless, further study should be conducted to explore the impact of the parasite on public and animal health.

Large-Scale Epidemiological Study on Toxoplasma gondii Seroprevalence and Risk Factors in Sheep in Estonia: Age, Farm Location, and Breed Associated with Seropositivity

Toxoplasma gondii is a zoonotic parasite of major veterinary and public health importance. The parasite is common in many host species in Estonia, however, information about the seroprevalence in the local sheep population is lacking. We estimated T. gondii seroprevalence and evaluated a limited selection of possible risk factors for T. gondii seropositivity in sheep raised in Estonia. Sera from 1599 sheep from 122 flocks, collected during 2012-2013, were diluted to 1:40 and screened for the presence of anti-T. gondii immunoglobulin G antibodies using a commercial direct agglutination test. The cutoff titer for seropositivity was 40. A total of 667 of the 1599 sheep were T. gondii seropositive, yielding an apparent seroprevalence estimate of 41.71% (95% confidence interval 39.31-44.14). At least one seropositive sheep was detected on the majority (88.53%) of the farms. T. gondii seroprevalence was significantly lower in lambs (age <12 months) than in adults (age ≥12 months) (11.11% and 42.16%, respectively). The seroprevalence increased steeply with age in the first years of life. A multivariable random-effects logistic regression model identified being an adult (odds ratio [OR] 9.55) and being from a farm located on the islands (OR 2.51) as risk factors for T. gondii seropositivity, while being of Texel breed appeared as a protective factor (OR 0.34) when compared with the Estonian Blackhead breed. Exposure to T. gondii was widespread among the investigated sheep. Undercooked meat and unpasteurized milk from sheep from Estonia should be considered possible sources of T. gondii infections to other hosts, including humans.

Seroprevalence of anti-Toxoplasma gondii antibodies in Egyptian sheep and goats

Background

Toxoplasmosis is a zoonotic disease that affects a wide range of animals, including small ruminants. Sheep and goats are considered as biological indicators for the contamination of the environment with Toxoplasma gondii oocysts. In addition, in countries such as Egypt, where sheep and goat meat is frequently consumed, T. gondii infection in small ruminants may also pose a public health risk. To establish baseline estimates of the prevalence of T. gondii infection in Egyptian small ruminants, we used an indirect immunofluorescence assay (IFA) and an enzyme-linked immunosorbent assay (ELISA) to assess the seroprevalence in 398 sheep from four Egyptian governorates (Cairo, Giza, Dakahlia and Sharkia) and in 100 goats from Dakahlia. The positive and negative agreements of both tests were calculated and the true prevalence was estimated using a Bayesian approach.

Results

The true prevalence of antibodies to T. gondii as determined by both tests was higher in Egyptian goats (62%) than in sheep for each province (between 4.1 and 26%). Sheep slaughtered at the Cairo abattoir had the lowest true prevalence (4.1%), while true prevalences in Dakahlia, Giza and Sharkia governorates (26%, 23% and 12%, respectively) were substantially higher.

Conclusions

The high prevalence of antibodies to T. gondii may indicate an important role of goat and sheep in the transmission of human toxoplasmosis in Egypt, given the habit of eating undercooked grilled mutton.

Transplacental transmission of Neospora caninum in naturally infected small ruminants from northeastern Brazil

ABSTRACT: Toxoplasma gondii and Neospora caninum are causative agents of abortion in sheep and goats. Thus, the present study aimed to describe the transplacental transmission of these protozoans in small ruminants of northeastern Brazil. Seventeen fetuses (6 goats and 11 sheep) from farms with history of abortion were necropsied and samples were collected from different tissues (brain, liver, lung, kidney and heart). The samples were analyzed by PCR, histopathology (HP) and immunohistochemistry (IHC) to evaluate whether T. gondii and/or N. caninum infection were the cause of abortion. None of the samples was positive for T. gondii according to PCR and IHC results. Some brain, liver, lung, kidney and heart samples of goat fetuses were positive for N. caninum by PCR. In the histopathology, mild mononuclear infiltration and necrosis with calcification were observed in the liver and brain of one goat fetus, respectively, that also was positive for N. caninum by PCR and IHC. The results confirmed vertical transmission of N. caninum in naturally infected goats of northeastern, Brazil.

The effect of lopinavir/ritonavir and lopinavir/ritonavir loaded PLGA nanoparticles on experimental toxoplasmosis

A marked reduction has been achieved in the incidence and clinical course of toxoplasmic encephalitis after the introduction of protease inhibitors within the treatment regimen of HIV (HIV-PIs). This work was undertaken to study for the first time, the efficacy of HIV-PIs, lopinavir/ritonavir (L/R), as a therapeutic agent in acute experimental toxoplasmosis. Lopinavir/ritonavir (L/R) were used in the same ratio present in aluvia, a known HIV-PIs drug used in the developing countries in the treatment regimens of AID's patient. Poly lactic-co-glycolic acid (PLGA) nanoparticles were used as a delivery system to L/R therapy. L/R alone or after its encapsulation on PLGA were given to Swiss strain albino mice that were infected with RH virulent toxoplasma strain. Both forms caused parasitological improvement in both mortality rate and parasite count. The higher efficacy was achieved by using L/R PLGA together with minimizing the effective dose. There was significant reduction in the parasite count in the peritoneal fluid and the liver. Parasite viability and infectivity were also significantly reduced. The anti-toxoplasma effect of the drug was attributed to the morphological distortion of the tachyzoites as evident by the ultrastructure examination and suppressed the egress of tachyzoites. L/R also induced changes that suggest apoptosis and autophagy of tachyzoites. The parasitophorous vacuole membrane was disrupted and vesiculated. The nanotubular networks inside the parasitophorous vacuole were disrupted. Therefore, the present work opens a new possible way for the approved HIV-PIs as an alternative treatment against acute toxoplasmosis. Furthermore, it increases the list of the opportunistic parasites that can be treated by this drug. The successful in vivo effect of HIV-PIs against Toxoplasma gondii suggests that this parasite may be a target in HIV treated patients, thus decrease the possibility of toxoplasmic encephalitis development.

Enrofloxacin and Toltrazuril Are Able to Reduce Toxoplasma gondii Growth in Human BeWo Trophoblastic Cells and Villous Explants from Human Third Trimester Pregnancy

Classical treatment for congenital toxoplasmosis is based on combination of sulfadiazine and pyrimethamine plus folinic acid. Due to teratogenic effects and bone marrow suppression caused by pyrimethamine, the establishment of new therapeutic strategies is indispensable to minimize the side effects and improve the control of infection. Previous studies demonstrated that enrofloxacin and toltrazuril reduced the incidence of Neospora caninum and Toxoplasma gondii infection. The aim of the present study was to evaluate the efficacy of enrofloxacin and toltrazuril in the control of T. gondii infection in human trophoblast cells (BeWo line) and in human villous explants from the third trimester. BeWo cells and villous were treated with several concentrations of enrofloxacin, toltrazuril, sulfadiazine, pyrimethamine, or combination of sulfadiazine+pyrimethamine, and the cellular or tissue viability was verified. Next, BeWo cells were infected by T. gondii (2F1 clone or the ME49 strain), whereas villous samples were only infected by the 2F1 clone. Then, infected cells and villous were treated with all antibiotics and the T. gondii intracellular proliferation as well as the cytokine production were analyzed. Finally, we evaluated the direct effect of enrofloxacin and toltrazuril in tachyzoites to verify possible changes in parasite structure. Enrofloxacin and toltrazuril did not decrease the viability of cells and villous in lower concentrations. Both drugs were able to significantly reduce the parasite intracellular proliferation in BeWo cells and villous explants when compared to untreated conditions. Regardless of the T. gondii strain, BeWo cells infected and treated with enrofloxacin or toltrazuril induced high levels of IL-6 and MIF. In villous explants, enrofloxacin induced high MIF production. Finally, the drugs increased the number of unviable parasites and triggered damage to tachyzoite structure. Taken together, it can be concluded that enrofloxacin and toltrazuril are able to control T. gondii infection in BeWo cells and villous explants, probably by a direct action on the host cells and parasites, which leads to modifications of cytokine release and tachyzoite structure.

Prevalence of Toxoplasma gondii infection in HIV-infected patients and food animals and direct genotyping of T. gondii isolates, Southern Ghana

Toxoplasma gondii is of public health and veterinary importance causing severe diseases in immunocompromised individuals including HIV/AIDS patients and in congenital cases and animals. There is limited information on the epidemiology of T. gondii infection in humans, particularly HIV patients and food animals and the parasite genotypes in Ghana. A total of 394 HIV-infected patients from three hospitals were screened for T. gondii anti-IgG and IgM using ELISA. DNAs from blood samples of seropositve participants and 95 brain tissues of food animals were PCR assayed to detect Toxoplasma gra6. DNA positive samples were genotyped using multilocus nested polymerase chain reaction restriction fragment length polymorphism at 10 loci: sag1, alt.sag2, sag3, btub, gra6, l358, c22-8, c29-2, pk1, and apico. The overall seroprevalence was 74.37% (293/394). Toxoplasma DNAs were detected in 3.07% of the seropositive participants and 9.47% of the animals. Six of the human DNA positive samples were partly typed at sag3: 33.33, 50, and 16.67% isolates had type I, II, and III alleles, respectively. All nine isolates from food animals typed at nine loci except apico were atypical: six isolates were identical to ToxoDB #41 and #145, and one was identical to TgCkBrRj2 all identified in Brazil. The genotype of two isolates has not been reported previously and was named as TgCtGh1. T. gondii seroprevalence is high among the HIV-infected individuals with T. gondii circulating in Ghana being genetically diverse.

Toxoplasma Gondii and Pre-treatment Protocols for Polymerase Chain Reaction Analysis of Milk Samples: A Field Trial in Sheep from Southern Italy

Toxoplasmosis is a zoonotic disease caused by the protozoan Toxoplasma gondii. Ingestion of raw milk has been suggested as a risk for transmission to humans. Here the authors evaluated pre-treatment protocols for DNA extraction on T. gondii tachyzoite-spiked sheep milk with the aim of identifying the method that resulted in the most rapid and reliable polymerase chain reaction (PCR) positivity. This protocol was then used to analyse milk samples from sheep of three different farms in Southern Italy, including real time PCR for DNA quantification and PCR-restriction fragment length polymorphism for genotyping. The pre-treatment protocol using ethylenediaminetetraacetic acid and Tris-HCl to remove casein gave the best results in the least amount of time compared to the others on spiked milk samples. One sample of 21 collected from sheep farms was positive on one-step PCR, real time PCR and resulted in a Type I genotype at one locus (SAG3). Milk usually contains a low number of tachyzoites and this could be a limiting factor for molecular identification. Our preliminary data has evaluated a rapid, cost-effective and sensitive protocol to treat milk before DNA extraction. The results of the present study also confirm the possibility of T. gondii transmission through consumption of raw milk and its unpasteurised derivatives.

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

AIM

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Congenital Toxoplasmosis in Chronically Infected and Subsequently Challenged Ewes

This experiment studied congenital transmission in sheep experimentally infected with oocysts of Toxoplasma gondii and reinfected at one of three stages of pregnancy. Twenty ewes were experimentally infected with T. gondii strain ME49 (day 0). After the T. gondii infection became chronic (IFAT≤512), the ewes were allocated with rams for coverage. After the diagnosis of pregnancy, these ewes were allocated into four experimental groups (n = 5): I-reinfected with T. gondii on the 40^th day of gestation (DG); II-reinfected on DG 80; III-reinfected on DG 120; and IV-saline solution on DG 120 (not reinfected). Five ewes (IFAT<64) were kept as negative controls (uninfected, group V), therefore in groups I-III were infected prior to pregnancy and re-infected during pregnancy, group IV was only infected prior to pregnancy, and group V was not infected. Parasitism by T. gondii was investigated (histopathology, immunohistochemistry, mouse bioassay and PCR) in mothers and lambs tissue. All ewes produced lambs serologically positive for T. gondii. The results of the mouse bioassay, immunohistochemistry and PCR assays revealed the presence of T. gondii in all 20 sheep and their lambs. The congenital transmission of T. gondii was associated with fetal loss and abnormalities in persistently infected sheep and in ewes infected and subsequently reinfected by this protozoan. Therefore, congenital T. gondii infection was common when ewes were chronically infected prior to pregnancy, with or without reinfection during at various stages of gestation.

Role of vertical transmission of Toxoplasma gondii in prevalence of infection

The parasite, Toxoplasma gondii, is a highly successful pathogen that infects around 30% of the global human population. Additionally, it is able to infect all warm blooded animals with high prevalence. This is surprising as it is a parasite of the cat and can only complete its full sexual cycle in that host. This review examines the important key routes of transmission: infective oocysts from the cat, ingestion of raw infected tissue and vertical transmission. The latter route of transmission has traditionally been thought to be rare. In this review, this assumption is examined and discussed in the light of the current literature. The available evidence points to the possibility that vertical transmission occurs frequently in natural populations of mice however the evidence in sheep is currently ambivalent and controversial. In humans, the situation appears as though vertical transmission may be rare although there is still much that is unexplained.

Seroprevalence and Spatial Distribution of Toxoplasmosis in Sheep and Goats in North-Eastern Region of Pakistan

Toxoplasmosis is a protozoan disease that is caused by Toxoplasma gondii in livestock and humans. Due to its medical and veterinary importance, it is essential to study the seroprevalence of T. gondii infection among humans and animals in various parts of the world. The major objective of this study was to determine the seroprevalence and spatial distribution of toxoplasmosis in small ruminants (sheep and goats) of north-eastern region, Pakistan. A total of 1,000 animals comprising of sheep (n=470) and goats (n=530) were examined for T. gondii infection by using ELISA. An epidemiological data was collected in the form of questionnaire. A surface has been generated by using method of interpolation in Arc GIS with the help of IDW (inverse distance weight). The results showed higher seroprevalence of T. gondii in goats (42.8%) as compared to sheep (26.2%). The seroprevalence was higher in females as compared to males in all examined ruminants. Similarly, there is a wide variation in the seroprevalence of T. gondii in different breeds of sheep and goats showing higher seroprevalence in Teddy (52.8%) and Damani breed (34.5%) of goat and sheep’s, respectively. The geographical and spatial distribution of T. gondii shows that it is widely distributed in different parts of the north-eastern region of Pakistan. Our results suggest widespread environmental contamination with T. gondii oocysts. It suggests us that small ruminants could be a potentially important source of T. gondii infection if their infected meat is consumed undercooked.

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

Abstract 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.

Seroprevalence and epidemiology of Toxoplasma gondii in farm animals in different regions of Egypt

Toxoplasmosis is a cosmopolitan protozoan disease that has been recorded in a wide range of vertebrate hosts, including humans. In response to the paucity of available data, this study was undertaken to comprehensively establish the seroprevalence of Toxoplasma gondii among various farm animals in different localities of Egypt. The latex agglutination test and TgGRA7-based enzyme-linked immunosorbent assay were used to screen the investigated animals for anti-T. gondii IgG antibodies. When only samples with simultaneously positive results for both the latex agglutination test and the TgGRA7-based ELISA were considered positive, 174 (26.7%) of 652 serum samples from different animals were seropositive. The prevalence of antibodies according to species was: sheep 38.7%, goats 28.7%, cattle 23.6%, and donkeys 22.6%. Thus, prevalence rate was significantly higher in sheep than in cattle or donkeys. The prevalence was also significantly higher in Kafr El Sheikh than in the other governorates investigated (Qena, Sohag, Minoufiya, and Matrouh). No significant differences were observed in age, sex, locality, or breeding system when evaluated as predisposing factors for T. gondii infection in cattle. In conclusion, this study demonstrates the high prevalence for T. gondii-specific antibodies among different animal species in southern and northern localities of Egypt, and provides valuable new data on the prevalence of T. gondii in donkeys, which are used as a food for carnivorous animals, particularly in the feline family, at Giza Zoo, Egypt.

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

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