Occurrence of anti-Neospora caninum and anti-Toxoplasma gondii IgG antibodies in goats and sheep in western Maranhão, Brazil

Seroprevalence and risk factors of Toxoplasma gondii infection in goats from South Punjab Province, Pakistan

Layyah District in South Punjab Province of Pakistan offers the most intensive caprine economy in the country; its Indus riverine and desert environment makes the area peculiar and worthy of specific investigations. This study aimed to investigate the prevalence of anti-Toxoplasma gondii (T. gondii) IgG-antibody in goats in serum samples and the potential risk factors. The prevalence of T. gondii infection was estimated using a two-stage sample design. All caprine farms in the study area were stratified by size, and from these 110 were randomly selected. Twelve goats (>1-year-old) were selected from each farm and a total of 1320 serum samples were collected and tested by ELISA. A questionnaire on the conditions and management practices of each farm was administered to 110 farmers. Four hundred and sixteen out of 1320 sera samples (31.5%) were found positive and 89% of the flock had at least one seropositive goat. The proportion of seropositive goats tested within each flock ranged from 8.3% to 83.3%. with several factors contributing to this heterogeneity. Goat age played a significant role in the presence of cats. Significant interactions were related to goat farms having floor of dirt and kitten presence. Moreover, age class, abortion history and water source supply were modulated by owner education levels. This is the first study to determine the prevalence of anti-T. gondii antibodies in goats sera in Layyah district and the largest carried out so far in Pakistan. The remarkable presence of T. gondii among goats in areas where goat farming plays a significant economic role may pose a production threat to the small-stock industry, as well as to public health and food safety. Therefore, investigations to identify high-risk goat populations are highly recommended in order to facilitate the implementation of local control strategies.

Seroprevalence and associated factors with Neospora caninum infection in sheep and goats slaughtered in the state of Paraíba, Brazil

The objective was to describe the seroprevalence of anti-Neospora caninum antibodies in goats and sheep slaughtered in the state of Paraíba and to identify possible associated factors with the infections. Two hundred twenty-nine samples from goats and two hundred five from sheep were analyzed by Indirect Immunofluorescence Reaction (IFAT) using a cutoff point of 1:50. The presence of anti-N. caninum antibodies was identified in 28.4% (65/ 229; 95% Confidence Interval: 22.6-34.2) of the goat samples and in 12.7% (26/ 205; 95% CI: 8.2 - 17.2) of the sheep samples. Contact between goats and dogs (Odds ratio 4.81; CI 1.13 - 2.67; p = 0.041) and cattle (OR. 1.87; CI 1.13 - 2.67; p = 0.002) was identified as a risk factor for goats and contact between sheep and dogs (OR 2.32; CI 1.58 - 3.14; p = 0.026) and history of abortion (OR 1.94; CI 1.28 - 2.90; p = 0.001) was considered a risk factor for sheep. The study revealed a high seroprevalence of anti-N. caninum antibodies in slaughtered goats and sheep in Paraíba. Risk factors such as contact with dogs/cattle and abortion history underscore the need for preventive measures to control infection and enhance animal health management.

Seroprevalence of Toxoplasma gondii infection in sheep and goats from different geographical regions of the world: Systematic review and meta-analysis

The Toxoplasma gondii is an obligate intracellular protozoan parasite which significantly impact small ruminant productivity, international animal trade and transboundary movement of animal across the globe. The seroprevalence of T. gondii infection (toxoplasmosis) in sheep and goats is widely studied in many parts of the world and there is a lack of comprehensive information on prevalence estimates considering the global and regional perspectives. The aim of the study was to use systematic review and meta-analysis methods to estimate the global and regional pooled seroprevalence of T. gondii infection in sheep and goats, as well as factors that influence prevalence estimations. Relevant articles reporting the seroprevalence of toxoplasmosis in sheep and/goats were searched in five electronic databases, including PubMed, Web of Science, Scopus, Embase and ProQuest. After the publications were checked to verify they fit the inclusion criteria, a total of 225 articles were included in the systematic review and meta-analysis, reflecting data from 70 countries/regions. The pooled prevalence was estimated using a random effect meta-analysis model. Overall, the seroprevalence of T. gondii infection was 33.86% (95% CI: 30.47-37.25%) in sheep and 31.78% (95% CI: 28.99-34.58%) in goats, with significant variation in prevalence estimates across geographical locations (p < .001). Substantial heterogeneity (I²  > 75%) was observed in most pooled seroprevalence estimates. The T. gondii infection in global sheep and goat population showed uptrend over the period. This information would be useful for epidemiologist, health authorities and farmers in order to plan future T. gondii survey and infection management strategies both locally and internationally.

Ovine Neosporosis: The Current Global Situation

Simple Summary

This review summarizes the current global situation of Neospora caninum infection in sheep by referring to all of the available descriptions of natural ovine neosporosis to date, focusing on epidemiology, clinical signs, lesions, and diagnosis. The data suggest that ovine neosporosis is more prevalent than currently thought, that it has increased in the last few decades, and that it should now be considered in the differential diagnosis when investigating abortion in sheep.

Abstract

In the past 20 years, Neospora caninum infection in sheep has been reported in at least 31 countries worldwide from all sheep-rearing continents (Europe, Asia, the Americas, Africa, and Oceania), and its role as an abortifacient agent is becoming more evident. Most studies of ovine neosporosis have focused on its epidemiology, based primarily on serological analysis, with only a few studies investigating the actual presence of the parasite by PCR and/or IHC. Individual seroprevalence rates were highly variable between countries, and even between regions within the same country, ranging from 0.0% to 67.4% positive. Furthermore, most of the studies were not directly comparable due to differences in experimental designs, sample sizes, husbandry systems, ecological factors, and serological tests (e.g., IFAT, ELISA, MAT, Western blot). The latter, along with the scarcity of studies on the relevance of N. caninum as an abortifacient agent, may bias the perception of the importance of this disease. This review summarizes the situation of N. caninum infection in sheep using all available published studies describing natural ovine neosporosis. The epidemiology shows that ovine neosporosis is found worldwide, and it poses a relevant risk to the sustainability of sheep flocks.

Neosporosis in sheep: a systematic review and meta-analysis of global seroprevalence and related risk factors

Neosporosis is recognized as the main cause of abortions in cattle worldwide and there is an increasing concern about its role in ovine reproductive losses; however, epidemiological studies regarding neosporosis in sheep are still limited. This meta-analysis aimed to estimate the global pooled seroprevalence and associated risk factors of ovine neosporosis. In the current report, a comprehensive strategy of search and data collection from 7 worldwide databases was performed. A final set of 73 studies (80 datasets) published from 2000 to 2021 were selected based on inclusion criteria, comprising data on 35,740 sheep (corresponding to 37,565 evaluated samples) from 30 countries worldwide. The global pooled seroprevalence of Neospora caninum infection in sheep estimated by the random-effects model was 13% (95% CI, 10-15) and showed high heterogeneity (Q = 5147.15, I² = 98%, p< 0.001). Furthermore, by meta-analyses of subgroups it was demonstrated for the first time that seroprevalence significantly varied between continents (highest in Africa; 20%, 95% CI, 4-44), WHO regions (highest in African Region; 42%, 95% CI, 36-48), countries (highest in Colombia; 79%, 95% CI, 61-92%) and diagnostic methods (highest by IFAT; 17%, 95% CI, 12-23). Meta-regression indicated significant increasing trends in the prevalence of ovine neosporosis with decrease in geographical latitude (coefficient = -0.013; p<0.001), whereas longitude did not influence it (coefficient = -0.001; p=0.365). Regarding associated risk factors, older sheep were more likely to be infected with N. caninum than younger ones (OR 1.42; 95% CI 1.08-1.87), and sheep bred under intensive or semi-intensive systems resulted less susceptible to be seropositive than those bred under extensive system (OR 0.65; 95% CI 0.42-0.99 and OR 0.74; 95% CI 0.62-0.89, respectively). Conversely, no apparent association was found between seroprevalence and other variables, such as sex (OR 1.06; 95% CI 0.9-1.24), the presence of dogs on the farm (OR 1.15; 95% CI 0.63-2.12) or the presence of abortion (OR 1.80; 95% CI 0.87-3.74). In conclusion, the seroprevalence of ovine neosporosis is widely and heterogeneously distributed throughout the world, and it is negatively associated with increasing geographical latitude. In addition, age and extensive production system represent risk factors, which suggest that the horizontal transmission route is relevant for this host species. It is recommended to pay more attention to this disease and emphasize the global need for more indexed studies concerning the seroprevalence and risk factors of ovine neosporosis to better understand the epidemiology of this coccidian infection.

A Meta-Analysis of the Prevalence of Toxoplasmosis in Livestock and Poultry Worldwide

Toxoplasma gondii causes toxoplasmosis with a global prevalence in the world. A large proportion of human illness is most frequently associated with consuming raw and undercooked meat or other animal products containing infective parasitic stages of T. gondii. This systematic review and meta-analysis study evaluated the prevalence of toxoplasmosis in cattle, sheep, camels, goats, and poultry worldwide. The search was performed in databases including PubMed, WoS, Scopus, Science Direct, Google Scholar, and ISC from 2000 to 2019 in Persian and English. The main inclusion criteria were the prevalence of toxoplasmosis among livestock and poultry and the prevalence indices by sample size. During these 20 years, the overall prevalence of toxoplasmosis in livestock and poultry was 28.3% (95% confidence interval (CI) 25-31.9%) using the random-effects meta-analysis model. The highest prevalence of T. gondii in livestock and poultry animals was found in Asia in 2014 with 89.8% (95% CI 78.5-95.5%). The lowest prevalence was found in Asia in 2013 with 1.26% (95% CI 0.4-3.8%). A quarter of livestock and poultry were infected with T. gondii. Since livestock products are globally important sources of people's diet, our findings are useful for policymakers to control T. gondii infection in livestock.

Spatial distribution and risk factors for sheep toxoplasmosis in Goiás, Brazilian Cerrado Region

The present study aimed to evaluate the spatial distribution and risk factors for infection by Toxoplasma gondii in sheep in the state of Goiás, located in the central-western region of Brazil. Through the immunofluorescence antibody test (IFAT), the seroprevalence of anti-T. gondii antibodies was analyzed in 1000 blood serum samples obtained from sheep in all macro and micro regions of the state of Goiás. Data related to sex, age of the animals, size of the farm, type of farm, water source, veterinary assistance, replacement of the herd, presence of domestic cats, presence of wild cats and presence of other wild animals were obtained at the sampling time. The differences between the seroprevalences obtained in relation to the variables analyzed were estimated using Pearson's chi-square test (χ2). The odds ratio (OR) values for each risk factor evaluated were statistically analyzed with a confidence interval of 95%. Positivity for IgG anti-T. gondii was observed (titer ≥64) in 34.3% (343/1000) of the samples, which ranged from 26.9% (31/115) to 44.2% (53/120) and from 21.8 (12/55) to 55.2% (16 / 29), respectively in the analyzed mesoregions and microregions. In all investigated regions of the State of Goiás, serum-reactive animals were detected with the age of the animals, the source of water, the form of replacement of the herd and the presence of domestic cats and wild animals risk factors statistically associated with the occurrence of T. gondii in animals.

Economic and public health importance of Toxoplasma gondii infections in sheep: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, control, and genetic diversity of T. gondii in sheep in the past decade. There is debate and uncertainty concerning repeat congenital infection as evidenced by finding T. gondii DNA in progeny of chronically infected sheep. However, there is no concrete evidence that T. gondii is the cause of repeated abortions in sheep. Recent data concerning pathogenesis of abortion in acutely infected sheep are reviewed. PCR-RFLP typing of T. gondii DNA derived from viable T. gondii isolates or tissues of infected sheep revealed low genetic diversity in sheep in Europe, Africa, Asia and North America but high diversity in South America. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Public health and economic importance of Toxoplasma gondii infections in goats: The last decade

Toxoplasma gondii infections are common in humans and animals worldwide. Toxoplasmosis in goats continues to be of public health and economic concern. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, treatment, and genetic diversity of T. gondii in goats in the past decade. There is debate and uncertainty regarding excretion of T. gondii in milk and the ingestion of raw milk as sources of T. gondii infection for humans. Toxoplasmosis can cause abortion and deaths even in adult goats. PCR-RFLP typing of T. gondii DNA derived from viable T. gondii isolates has revealed genetic diversity in goats in North and South America. The significance of T. gondii isolates in domestic goats usually associated with wildlife in USA is discussed. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Seroepidemiology of Neospora caninum among goats (Capra hircus) in the state of Paraíba, northeastern Brazil

ABSTRACT Although goat dairy farms in Brazil may have a higher risk of infection by Neospora caninum than beef farms, risk factor evaluation on a representative population remains to be fully established in Brazil. Accordingly, this study aimed to establish the occurrence of anti-N. caninum antibodies and factors associated with exposure in 406 blood samples from five dairy and three beef goat farms in the state of Paraíba, northeastern Brazil. Anti-N. caninum antibodies were detected by indirect immunofluorescence assay (IFA), with samples considered positive when reacting with dilution ≥ 1:50. A total of 106/406 goats (26.11%; 95% CI: 21.96-30.72%) were seroreactive comprising 2/61 (3.28%), 10/45 (22.22%), 13/50 (26.00%), 17/51 (33.33%) to 29/46 (63.04%) in dairy farms, and from 3/54 (5.56%), 12/50 (24.00%) to 20/49 (40.82%) on the beef farms. No significant associations were found in relation to age, gender, dairy versus beef farms, occurrence of abortions or mummified fetuses, and seroreactivity to N. caninum (P>0.05). In conclusion, goat farms in the state of Paraíba showed the highest occurrence of anti-N. caninum antibodies to date in Brazil.

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.

All about neosporosis in Brazil

Neospora caninum is protozoan parasite with domestic and wild dogs, coyotes and grey wolves as the definitive hosts and many warm-blooded animals as intermediate hosts. It was cultivated and named in 1988. Neosporosis is a major disease of cattle and has no public health significance. Since 1990's N. caninum has emerged as a major cause of abortion in cattle worldwide, including in Brazil. N. caninum also causes clinical infections in several other animal species. Considerable progress has been made in understanding the biology of N. caninum and there are more than 200 papers on this subject from Brazil. However, most of the reports on neosporosis from Brazil are serological surveys. Overall, little is known of clinical neosporosis in Brazil, particularly cattle. The few reports pertain to sporadic cases of abortion with no information on epidemics or storms of abortion. The objective of the present review is to summarize all reports from Brazil and suggest topic for further research, including prevalence of N. caninum oocysts in soil or in canine feces, and determining if there are additional definitive hosts, other than the domestic dog. There is need for a national survey in cattle using defined parameters. Future researches should focus on molecular characterization of N. caninum strains, possibility of vaccine production and relationship between wildlife and livestock epidemiology.

Incidence and vertical transmission rate of Neospora caninum in sheep

The infection by Neospora caninum in sheep can lead to abortion and the birth of weak and debilitated lambs. The aim of this study was to assess the incidence of natural infection by Neospora caninum and the vertical transmission rate among sheep. A flock of 50 sheep was monitored for serum antibody titres against N. caninum and seroconversion over a period of six months using an indirect ELISA technique. The offspring of the herd was also investigated regarding anti-N. caninum antibodies to determine the vertical transmission rate through the indirect immunofluorescence technique. The initial and final prevalences of infection by N. caninum were 26.0% (13/50) and 72.0% (36/50), respectively, and the incidence of infection by N. caninum in the present study was 62.2% (23/37). The vertical transmission rate found was 15.4% (2/13). A high incidence of infection by N. caninum in sheep was observed, and this is the first report assessing the incidence of N. caninum among naturally infected sheep.

Occurrences of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in sheep from four districts of Tocantins state, Brazilian Legal Amazon Region

Toxoplasmosis and neosporosis have been recognized as economically important diseases with considerable impact on the livestock industry. Little is known concerning the occurrence of Toxoplasma gondii and Neospora caninum in sheep from Tocantins state, Brazil. Here, we investigated antibodies against these parasites and associated factors in 182 sheep from Araguaína, Santa Terezinha do Tocantins, Arguianópolis and Palmeiras do Tocantins districts, Tocantins. Sheep sera were assayed for T. gondii and N. caninum IgG antibodies by indirect fluorescence antibody test (IFAT), using cut-off point at a dilution of 1:40 and 1:25 respectively. The prevalence of seropositive animal for T. gondii was 13.74% and 13.74% for N. caninum. None of the characteristics studied including reproductive problems, presence of cats, presence of dogs and veterinary care (p>0.05) was associated with occurrence of T. gondii or N. caninum infection. Only breed was identified as associated factor for the occurrence of toxoplasmosis in sheep (p<0.05). The present study is the first report on serum occurrence of T. gondii and N. caninum in sheep from the state of Tocantins, Brazil.

Prevalence and risk factors for Toxoplasma gondii infection in meat animals and meat products destined for human consumption

Toxoplasma gondii is a protozoan parasite that is responsible for approximately 24% of all estimated deaths attributed to foodborne pathogens in the United States. Human infection results from accidental ingestion of oocysts from the environment, in water, or on insufficiently washed produce or from consumption of raw or undercooked meat products that contain T. gondii tissue cysts. This review focused on studies of T. gondii in meat because many human T. gondii infections are acquired through consumption of raw or undercooked meat. Prevalence of T. gondii is higher in conventionally reared pigs, sheep, and poultry than in cattle and is greater in meat products from organic than from conventionally reared meat animals because of outdoor access, which poses substantially greater opportunities for exposure to infected rodents, wildlife, and oocyst-contaminated feed, water, or environmental surfaces. Risk factors related to T. gondii exposure for livestock include farm type, feed source, presence of cats, methods of rodent and bird control, methods of carcass handling, and water quality. This review serves as a useful resource and information repository for informing quantitative risk assessment studies for T. gondii infection in humans through meat consumption.

First report of seroprevalence of Toxoplasma gondii and Neospora caninum in dairy sheep from Humid Pampa, Argentina

The aim of this study was to describe the occurrence of antibodies to Toxoplasma gondii and Neospora caninum in dairy sheep from the Humid Pampa region, Argentina. Blood samples from 704 dairy sheep belonging to six flocks were collected. Using a cut off titer of 1:50, an indirect fluorescence antibody test was used. Antibodies to T. gondii or N. caninum were detected in 17.3 % (n = 122) and 3 % (n = 21), respectively. All the flocks had at least one seropositive animal to T. gondii but two of them had no seropositive sheep to N. caninum. Fifty-two of 122 (42.6 %) positive samples to T. gondii had antibody titers higher than 1:400. There was a significantly higher proportion of T. gondii seropositive animals in females and older sheep (p < 0.05). Ten of 21 (52.3 %) positive samples to N. caninum had antibody titers higher than 1:400. This is the first report of seroprevalence of T. gondii and N. caninum in dairy sheep from Humid Pampa, Argentina. Further research is required for a better understanding of the role of toxoplasmosis and neosporosis in dairy sheep in Argentina.

Risk factors associated with Toxoplasma gondii seroprevalence in goats in the State of Paraíba, Brazil

A cross-sectional study based on planned sampling was carried out to determine flock-level risk factors associated with Toxoplasma gondii antibody prevalence in dairy goat flocks in a semiarid region of northeastern Brazil. Serum samples from 975 adult dairy goats from 110 flocks were examined by indirect immonufluorescent antibody test (IFAT), using cut-off point at 1:64 dilution. From the 110 flocks, 77 presented at least one seropositive animal, corresponding to a prevalence of 70% (95% CI: 60.5-78.4%). Out of the 975 animals, 177 (18.1%; 95% CI = 15.8-20.7%) tested positive. The presence of toxic plants (OR = 5.11; P = 0.045) and the fact that goat breeding is not the main activity on the farm (OR = 3.34; P = 0.014) were identified as risk factors. The results of the present study showed evidence of the presence of T. gondii infection in dairy goats from a semiarid region of northeastern Brazil using planned sampling. Further studies are needed to elucidate the importance of the identified risk factors in the epidemiology of the infection.