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

Experimental infection with Neospora caninum in Texel ewes at different stages of gestation

In this study Texel sheep, at different stages of pregnancy, were experimentally infected with Neospora caninum. Eleven ewes, seronegative for N. caninum and Toxoplasma gondii, were inoculated 30 days before breeding (Group A), or at 65, 100, and 120 days of gestation (Groups B, C, and D). The group E (control) was inoculated with PBS. Blood samples were collected at -2, 2, 5, and 7 days post-infection (dpi), and weekly up to 42 dpi, for hematology, parasitemia (PCR), and serology (RIFI) assessments. Blood and tissue samples were collected from the lambs for molecular and histological analyses. All animals in Groups B, C, and D were seroconverted, whilst those in groups A and E remained seronegative. Parasitic DNA was detected in the blood of two ewes (groups B and D) and a lamb (group D), and in the brain of a lamb (group B). The parasitemia-positive ewe in group B delivered a weak and seropositive lamb, and had parasitic DNA in its placenta. These results confirm the vertical transmission of N. caninum in ewes inoculated at the beginning and end of pregnancy. The absence of abortions and other clinical signs suggest that Texel sheep may potentially have resistance to N. caninum.

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.

Toxoplasma gondii and Neospora caninum infections in sheep and goats in Switzerland: Seroprevalence and occurrence in aborted foetuses

Toxoplasma gondii and Neospora caninum infections are important causes of abortion in ruminants. Besides, meat from T. gondii infected animals represent a major infection source for humans. The occurrence of these protozoan parasites in Switzerland was investigated both, in a nationwide cross-sectional serological survey, and by molecular methods in aborted sheep and goat foetuses. A total of 653 sheep from 143 farms and 748 goats from 164 farms were tested by commercial ELISAs and inconclusive results were defined by immunoblot. Besides, a risk factor analysis for seropositivity was performed. The observed seroprevalences for T. gondii in sheep and goats were 66.3% and 50.5% at the animal level, and 90.9% and 81.1% at the farm level, respectively. For N. caninum, the detected seroprevalences in sheep and goats were 0.8% and 0.9% at the animal level, and 2.8% and 1.8% at the farm level, respectively. Older small ruminants, and sheep (vs. goats) had a higher risk of being seropositive to T. gondii. Alpine grazing in summer was identified as a protective factor for seropositivity to T. gondii in both animal species. Toxoplasma gondii and N. caninum DNA were detected in 6.1% and 2.4% (n = 82), and in 6.8% and 1.4% (n = 73) of the tested ovine and caprine foetuses, respectively. These results suggest the involvement of these parasites in abortions and reveal a high prevalence of T. gondii and lower prevalence of N. caninum infections in small ruminants in Switzerland. They also suggest that consumption of undercooked meat from T. gondii infected sheep and goats may represent a risk for public health.

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Toxoplasma gondii infections are very frequent in Swiss small ruminants.

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Meat from infected small ruminants represents a source for T. gondii human infection.

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Sheep have a higher risk of T. gondii seropositivity than goats.

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Neospora caninum seroprevalences in Swiss sheep and goats are very low.

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T. gondii and N. caninum were detected in ovine and caprine abortions in Switzerland.

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T. gondii and N. caninum should be considered in diagnosis of small ruminant abortion.

Seroprevalence and Risk Factors for Toxoplasma gondii and Neospora caninum in Cattle in Portugal

Simple Summary

Neospora caninum and Toxoplasma gondii are apicomplexan parasites with a worldwide distribution and both infect cattle. While the importance of N. caninum is mainly linked to reproductive losses, concern has been raised about the role of beef as a source of food-borne toxoplasmosis in humans. Little is known about the prevalence of these parasites in cattle in Portugal. This study aimed to evaluate the seroprevalence and risk factors for N. caninum and T. gondii in naturally exposed cattle from different geographical areas in the country. Results point to a low but widespread seroprevalence of T. gondii, while that of N. caninum was found to be in the same range as reported in other Mediterranean countries. Distribution of both parasites may be explained by common climate factors and management practices identified as significant predictors of infection in the study.

Abstract

Neospora caninum has a worldwide economic impact as an important cause of abortion in cattle, while Toxoplasma gondii, another abortifacient pathogen, is globally a major foodborne zoonotic threat. The study aimed to evaluate the seroprevalence and risk factors for the two parasites in cattle in Portugal. A total of 612 sera from 35 farms were tested by an in-house p30 ELISA for T. gondii and p38 ELISA for N. caninum. T. gondii positive and suspicious sera were confirmed by p30 Western blot or IFAT. T. gondii and N. caninum animal seroprevalence was 9.2% (95%CI 7.1–11.7) and 17.2% (95% CI 14.4–20.4) and herd seroprevalence was 51.4% (95% CI 35.6–67.0) and 68.6% (95% CI 52.0–81.5), respectively. At the univariable level, climate area and precipitation of wettest month, driest month, driest quarter, and warmest quarter were significant predictors of seropositivity for both. N. caninum seropositivity was more likely in the region Norte, densely populated areas, and intensive production, and the probability of T. gondii seropositivity decreased with herd size. Results confirm the need to consider neosporosis in the differential diagnosis of cattle reproductive disorders in Portugal and may be valuable to inform source attribution models for human toxoplasmosis.

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.

Dynamics of Neospora caninum-Associated Abortions in a Dairy Sheep Flock and Results of a Test-and-Cull Control Programme

Neospora caninum is an apicomplexan parasite that can cause abortions and perinatal mortality in sheep. Although ovine neosporosis has been described worldwide, there is a lack of information about the relationship between N. caninum serostatus and the reproductive performance. In this study, we described the infection dynamics in a dairy sheep flock with an abortion rate up to 25% and a N. caninum seroprevalence of 32%. Abortions were recorded in 36% and 9% of seropositive and seronegative sheep, respectively. Seropositive sheep were more likely to abort twice (OR = 4.44) or three or more times (OR = 10.13) than seronegative sheep. Endogenous transplacental transmission was the main route of transmission since 86% of seropositive sheep had seropositive offspring. Within dams that had any abortion, seropositive sheep were more likely than seronegative ones to have female descendants that aborted (OR = 8.12). The slight increase in seropositivity with the age, the low percentage of animals with postnatal seroconversion or with low avidity antibodies, and the seropositivity of one flock dog, indicated that horizontal transmission might have some relevance in this flock. A control programme based on selective culling of seropositive sheep and replacement with seronegative animals was effective in reducing the abortion rate to 7.2%.

The global seroprevalence of Toxoplasma gondii infection in bovines: a systematic review and meta-analysis

Bovines, especially cattle, are considered as one of the main sources of Toxoplasma gondii infection for humans. A more comprehensive understanding of the occurrence of T. gondii is needed to provide a global perspective on the prevalence of T. gondii in bovines. Here, we present the results of the first systematic review and meta-analysis on the global T. gondii seroprevalence in bovines. Six databases (PubMed, ScienceDirect, Web of Science, Scopus, ProQuest and Google Scholar) were comprehensively searched for relevant studies published between 1 January 1967 and 30 May 2019. Among 7691 publications searched, 178 studies (from 50 countries) with 193 datasets were included in the meta-analysis. The global pooled and weighted seroprevalence of T. gondii among bovines was 17.91% [95% confidence interval (CI): 15.32–20.6]. Weighted prevalence based on the host was as follows: cattle 16.94% (95% CI: 14.25–19.81), buffalo 22.26% (95% CI: 16.8–29), yak 23% (95% CI: 14–33) and bison 8.1% (95% CI: 3.9–13.7). Continued monitoring on the status of T. gondii seroprevalence in bovines is essential. Study on the prevalence of T. gondii in the products of bovines such as milk, meat, etc., which are considered as the source of transmission of infection to humans, is recommended.

Prevalence of toxoplasmosis in semi-domesticated and pet cats within and around Bangkok, Thailand

Background

Toxoplasmosis is one of the most common parasitic zoonoses worldwide. Cats become infected after ingesting infected tissue cysts. The objective of the present study was to compare the prevalence of toxoplasmosis in pet cats and semi-domesticated cats in the Bangkok metropolitan region. A survey of Toxoplasma infection was conducted in 260 cats (median age [range]: 3 years [10 months–10 years]; 155 females and 105 males) by collecting blood samples from 130 client-owned pet cats and 130 semi-domesticated cats within and around Bangkok during 2016–2017 using indirect fluorescence antibody tests. An IgG antibody to Toxoplasma antigen ratio of ≥1:100 was considered positive for Toxoplasma infection.

Results

The overall prevalence of T. gondii in cats was 6.5% (17/260). The prevalence of T. gondii in semi-domesticated cats and pet cats was 11.5 and 1.5%, respectively. Semi-domesticated cats aged 1–5 years (14.9%) had a higher prevalence of infection than domesticated cats (1.3%, p = 0.002) of the same age. The odds (95% confidence interval [CI]) of having T. gondii infection in semi-domesticated cats were 8.34 (1.86–76.29, p = 0.0017) times higher than in pet cats. Interestingly, there was an association between T. gondii infection according to city ​region (p = 0.002). The odds (95% CI) of having T. gondii infection in cats living in the inner city were 4.96 (1.03–47.16, p = 0.023) times higher than cats living in the suburb and the vicinity.

Conclusions

The present study identified a higher prevalence of Toxoplasma infection in semi-domesticated cats compared with pet cats. The semi-domesticated cats could serve as a zoonotic reservoir. Public health regulations should be implemented to prevent toxoplasmosis spread.

Beware of dogs! Domestic animals as a threat for wildlife conservation in Alpine protected areas

Diseases are natural regulating factors of wildlife populations, but some pathogens may become an important threat in wildlife conservation, especially for endangered species. The presence of domestic animals may foster the spread of diseases in natural population, although their role in the dynamic of infections in wildlife is not clear. In this study, we investigated the presence and prevalence of a range of multi-host pathogens in wild species (red fox, Eurasian badger, beech marten, pine marten, stoat for a total of 89 carcasses analysed) and domestic animals (n = 52 shepherd and n = 25 companion dogs) living in a protected area of the Alps (the Gran Paradiso National Park) and discussed the role of domestic dogs as possible source of infection for wild species. Our results showed that domestic dogs are potential shedder of three important pathogens: Canine distemper virus, Toxoplasma sp. and Neospora caninum. In particular, shepherd dogs seem to represent a threat for wildlife as they are exposed to multiple pathogens because of free-roaming, scavenging lifestyles and close proximity to livestock. However, also companion dogs more subject to veterinary care may foster the spread of pathogens. Our results highlight the importance of regulating the access of domestic dogs to protected areas that aim at preserving biodiversity and enhancing the conservation of endangered species.

Seroepidemiology of Toxoplasma gondii in wild ruminants in Spain

Toxoplasmosis is a parasitic zoonosis caused by Toxoplasma gondii which infects warm-blooded species worldwide. Humans can be infected through ingestion of tissue cysts from raw or undercooked meat, including game meat. A nationwide large-scale cross-sectional study was conducted to assess exposure to T. gondii in seven wild ruminant species in Spain. A total of 2,040 serum samples from 77 sampling sites randomly distributed in the five bioregions (BRs) covering mainland Spain were tested for antibodies against T. gondii using the modified agglutination test. The overall seroprevalence was 22.0% (449/2,040). Seroprevalence by species in decreasing order was as follows: 39.6% (141/356) in roe deer (Capreolus capreolus), 37.1% (138/372) in fallow deer (Dama dama), 16.6% (92/553) in red deer (Cervus elaphus), 14.0% (26/186) in Southern chamois (Rupicapra pyrenaica), 11.5% (24/209) in mouflon (Ovis aries musimon), 7.8% (27/346) in Iberian wild goat (Capra pyrenaica) and 5.6% (1/18) in Barbary sheep (Ammotragus lervia). Seropositivity was detected in 74.0% (57/77) of the sampling sites. Results indicate widespread but not homogeneous exposure to T. gondii in wild ruminant populations in Spain during the last two decades and highlight differences related to animal species and spatial distribution of these species in this country; this implies potential consequences of T. gondii for animal health, conservation and public health.

Epidemiologic and Public Health Significance of Toxoplasma gondii Infections in Venison: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The ingestion of food or water contaminated with oocysts excreted by infected cats or ingestion of uncooked or undercooked meat containing tissue cysts of T. gondii are the 2 major modes of transmission of T. gondii. Deer are a popular game. Recently, outbreaks of clinical toxoplasmosis were reported in humans in North America linked to ingestion of undercooked venison. Here, we review prevalence, persistence of infection, clinical disease, epidemiology, and public health risks of T. gondii infections in deer and other cervids for the past decade. Estimates of worldwide serological prevalence are summarized individually for each species of deer, elk, moose, and caribou. Genetic diversity of 112 viable isolates of T. gondii from cervids is discussed, including its public health significance. Prevalence of T. gondii in deer is very high. Any part of a deer, including liver, spleen, and muscles, should be cooked thoroughly before human consumption.

Seroprevalence and risk factors of Toxoplasma gondii infection in wild ungulates that cohabit in a natural park with human-animal interaction in the Mediterranean ecosystem

The possibility of Toxoplasma gondii transmitted from game meat to humans is of public health concern. Here we determined seroprevalence and risk factors associated with T. gondii in large game ungulates that cohabit in Sierras de Cazorla, Segura and Las Villas Natural Park (SCSV-NP) (Southern Spain), a natural park with high human-animal interaction. Antibodies against T. gondii in 328 wild ungulates were assayed by the modified agglutination test (MAT ≥ 1:25). Antibodies were found in 39 (11.9%, 95% CI: 8.4-15.4) wild ungulates, with seroprevalence levels of 20.8% in wild boars (Sus scrofa) (5/24), 19.0% in fallow deer (Dama dama) (12/63), 13.9% in Iberian ibex (Capra pyrenaica hispanica) (14/101), 7.9% in red deer (Cervus elaphus) (6/76), and 3.1% in mouflons (Ovis aries musimon) (2/64). Significantly higher seroprevalence was observed in fallow deer and wild boars compared to mouflons. Animals living close to urban areas (<2 km) had 4.6-times higher risk compared to those living at >5 km of urban areas. The results indicate high circulation of T. gondii in wild ungulates in SCSV-NP, which is of animal and public health concern. The increased seroprevalence of T. gondii detected in wildlife ungulates living close to urban areas may increase human infection in those areas if meat from infected animals is consumed raw or undercooked.

Public Health Significance of Toxoplasma gondii Infections in Cattle: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The ingestion of food or water contaminated with oocysts excreted by infected cats or ingesting uncooked or undercooked meat containing tissue cysts of T. gondii are the 2 major modes of transmission of T. gondii. Viable T. gondii is more prevalent in pork and lamb than in beef. In the past decade, there have been many articles on the high seroprevalence in cattle, particularly from China. There is a report of an outbreak of acute toxoplasmosis in humans suspected to be linked to the ingestion of Artisan fresh cheese from cow's milk. There are conflicting reports concerning the rate of congenital transmission of T. gondii in cattle, especially from Brazil. In a report from Brazil, viable T. gondii was isolated from the blood of 1 of 60 pregnant cows slaughtered at an abattoir and from 1 fetus. The role of beef in the epidemiology of T. gondii infections is still not clear. Here, we review prevalence, persistence of infection, clinical disease, epidemiology, and public health risks of T. gondii infections in cattle from beef and cow's milk worldwide for the past decade.

Long-Term Determinants of the Seroprevalence of Toxoplasma gondii in a Wild Ungulate Community

Toxoplasma gondii is an obligate intracellular protozoan which infects warm-blooded vertebrates, including humans, worldwide. In the present study, the epidemiology of T. gondii was studied in the wild ungulate host community (wild boar, red deer, and fallow deer) of Doñana National Park (DNP, south-western Spain) for 13 years (2005-2018). We assessed several variables which potentially operate in the medium and long-term (environmental features, population, and stochastic factors). Overall, the wild ungulate host community of DNP had high seroprevalence values of T. gondii (STG; % ± confidence interval (CI) 95%; wild boar (Sus scrofa) 39 ± 3.3, n = 698; red deer (Cervus elaphus) 30.7 ± 4.4, n = 423; fallow deer (Dama dama) 29.7 ± 4.2, n = 452). The complex interplay of hosts and ecological/epidemiological niches, together with the optimal climatic conditions for the survival of oocysts that converge in this area may favor the spread of the parasite in its host community. The temporal evolution of STG oscillated considerably, mostly in deer species. The relationships shown by statistical models indicated that several factors determined species patterns. Concomitance of effects among species, indicated that relevant drivers of risk operated at the community level. Our focus, addressing factors operating at broad temporal scale, allows showing their impacts on the epidemiology of T. gondii and its trends. This approach is key to understanding the epidemiology and ecology to T. gondii infection in wild host communities in a context where the decline in seroprevalence leads to loss of immunity in humans.

A systematic review and meta-analysis of Toxoplasma gondii in roe deer (Capreolus capreolus) and red deer (Cervus elaphus) in Europe

The objective of this systematic review and meta-analysis was to summarize the available knowledge on the seroprevalence of T. gondii in roe deer (Capreolus capreolus) and red deer (Cervus elaphus) in Europe. A computerized literature search of electronic databases (PubMed and CAB abstracts) was performed along with hand searches of library resources for relevant papers, books, abstracts and conference proceedings. A random-effect model was employed to calculate pooled seroprevalence estimates with 95% confidence intervals, and I² statistic was used to assess heterogeneity. Further, moderator analysis was performed to evaluate the effect of geographical area on the seroprevalence in roe deer. From a total of 190 studies initially identified, 16 and 8 articles were included for roe deer and red deer, respectively. These comprise 3,913 roe deer and 2,913 red deer from different European countries. The pooled seroprevalence was estimated to be 29% (95% CI: 23%-35%) in roe deer and 15% (95% CI: 10%-20%) in red deer. High heterogeneity was detected in the seroprevalence data within each species. In roe deer, the pooled seroprevalence estimate was significantly different according to geographical area with 40% (95% CI: 31%-49%) in Western Europe, 31% (95% CI: 21%-43%) in Northern Europe, 27% (95% CI: 15%-41%) in Eastern Europe and 21% (95% CI: 14%-28%) in Southern Europe. The present study indicates a moderate exposure to T. gondii in roe deer and red deer in Europe, with very high prevalence in Western Europe. Our results highlight the significant risk associated to the consumption of venison, encouraging proper handling and cooking of game meat to prevent toxoplasmosis in humans.

Epidemiological surveillance of Toxoplasma gondii in small ruminants in southern Spain

Toxoplasmosis, caused by the protozoan Toxoplasma gondii, is a worldwide zoonotic disease, which affects most warm-blooded species. Besides the zoonotic relevance, toxoplasmosis is one of the major causes of reproductive disorders in small ruminants. A cross-sectional study was carried out to determine the seroprevalence, spatial distribution and risk factors associated with T. gondii infection in sheep and goats in southern Spain. During 2015-2017, a total of 1,943 small ruminants (998 sheep and 945 goats) from 127 flocks were tested for antibodies against T. gondii using the modified agglutination test (MAT, cut-off 1:25). Antibodies against T. gondii were detected in 464 of the 998 sheep (46.5 %; CI95 %: 43.4-49.6%) and 362 of the 945 goats (38.3 %; CI95 %: 35.2-41.4%) tested. The farm prevalence was 98.4 % (CI95 %: 95.4-100%) for sheep and 93.7 % (CI95 %: 87.6-99.7%) for goats. The generalized estimating equation analysis showed that presence of cats and existence of previous reproductive disorders were risk factors potentially associated with T. gondii seropositivity in small ruminants. Two statistically significant spatial clusters (P < 0.001) were identified. The seroprevalence observed in the present study indicates a widespread exposure to T. gondii in sheep and goats in southern Spain, which might have important implications for animal and public health. Management measures should be implemented in small ruminant farms in this region in order to reduce the risk of T. gondii infections, particularly in those areas identified in the spatial analysis.

The global seroprevalence of Toxoplasma gondii in deer from 1978 to 2019: A systematic review and meta-analysis

Toxoplasma gondii infecting virtually all warm-blooded animals, including humans, is an intracellular protozoan parasite. The immunocompromised patients or pregnant women infected by Toxoplasma usually can cause encephalitis or abortion. Deer are also the important intermediate host of the parasite and people can be infected by ingesting the undercooked venison. Therefore, to raise the attention of the researchers and T. gondii infection on people in deer, we conducted the meta-analysis. All potential publications on the T. gondii infection in deer were retrieved by searching the PubMed, ScienceDirect, Springer- Link, China National Knowledge Infrastructure (CNKI), WanFang, and VIP Chinese Journal Databases. Finally, a total of 48 publications were included. The pooled seroprevalence of T. gondii infection in deer was 22.92% (95% CI 17.89-28.38) calculated by the random effect model. The seroprevalence of T. gondii infection in deer was the lowest in Asia (12.72%, 95% CI 6.29-20.89), and the highest in North America (32.21%, 95% CI 20.32-45.39). The highest point estimate of deer T. gondii in detection method subgroup was using MAT (31.28%, 95% CI 20.15-43.61). The estimated pooled seroprevalence of T. gondii infection in elk (63.50%, 95% CI 50.01-76.01) was higher than other types of deer. Our meta-regression analysis found that the subgroups including region, sampling year, age, climate, and deer species may be the main heterogeneous source in our meta-analysis. It is necessary to monitor the seroprevalence of T. gondii infection in deer at all times. Furthermore, people should be taken to precautions when ingesting the venison by cooking it well before serving to prevent the T. gondii infection via eating venison.

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.

Research into Neospora caninum-What Have We Learnt in the Last Thirty Years?

BACKGROUND

Neospora caninum has been recognised world-wide, first as a disease of dogs, then as an important cause of abortions in cattle for the past thirty years. Over that time period, there have been improvements in the diagnosis of infection and abortion, new tests have been developed and validated, and it is timely to review progress to date.

METHODS

Bibliometric methods were used to identify major trends and research topics present in the published literature on N. caninum. The tools used were SWIFT-Review, VOSviewer and SciMAT, along with the published papers found in the MEDLINE, Dimensions and Web of Science databases. A systematic review of the published Neospora literature (n = 2933) was also carried out via MEDLINE and systematically appraised for publications relevant to the pathogenesis, pathology and diagnosis of Neospora abortions.

RESULTS

A total of 92 publications were included in the final analysis and grouped into four main time periods. In these four different time periods, the main research themes were "dogs", "abortion", "seroprevalence" and "infection". Diagnostics, including PCR, dominated the first two time periods, with an increased focus on transmission and abortions, and its risk factors in cattle.

CONCLUSIONS

Longitudinal analyses indicated that the main themes were consistently investigated over the last 30 years through a wide range of studies, with evolving emphasis initially on dogs and diagnostic test development, followed by application to cattle, the identification of the risk factors leading to abortion, and in the latter time periods, an understanding of the immunity and a search for vaccines.

A Multi-Pathogen Screening of Captive Reindeer (Rangifer tarandus) in Germany Based on Serological and Molecular Assays

Captive reindeer in German zoos and wildlife parks live outside their natural geographic range and are exposed to a variety of viral, bacterial and protozoan pathogens, some host-specific and some which they are not exposed to in their native habitat. Reindeer blood samples and ticks collected in 2013 from 123 reindeer at 16 different zoological facilities were available from a previous study. The aims of this study were to assess the serological status of these animals with regards to various microorganisms as well as to test ticks (Ixodes ricinus) and blood samples for the presence of Anaplasma spp. DNA in order to evaluate the exposure of captive reindeer in Germany to a variety of pathogens. A total of 119 or 118 serum samples were screened (ELISA) and antibodies were detected (seropositive/tested, prevalence, confidence interval) against alphaherpesvirus (24/119, 20.3%, CI: 13.9–28.3), bluetongue virus (BTV; 4/119, 3.4%, CI: 1.0–8.7), malignant catarrhal fever related gammaherpesvirus (MCFV-related gammaherpesvirus; 7/119, 5.9%, CI: 2.7–11.9), pestivirus (5/118, 4.2%, CI: 1.6–9.8), Schmallenberg virus (SBV; 70/118, 59.3%, CI: 50.3–67.8), smooth Brucella spp. (1/118; 0.9%, CI: 0–5.1), Neospora caninum (5/118, 4.2%, CI: 1.6–9.8), and Toxoplasma gondii (62/119, 52.1%, CI: 43.2–60.9). These results suggested the exposure of reindeer to all tested pathogens. Moreover, real-time PCR for Anaplasma phagocytophilum targeting the partial msp2 gene was performed on DNA extracted from whole blood samples from reindeer (n = 123) and from ticks (n = 49) collected from 22 reindeer in seven different facilities. In addition to the real-time PCR, a semi-nested PCR for the partial groEL gene, and a nested PCR targeting the partial 16S rRNA gene were performed. DNA of A. phagocytophilum was detected in 17 reindeer (13.8%) and 15 ticks (30.6%). Three of the five reindeer with ticks having A. phagocytophilum DNA also had such DNA in blood. These results indicate that captive reindeer can be exposed to several ruminant pathogens that they hitherto had no known exposure to through their natural geographical distribution and habitats as shown for Culicoides-borne BTV and SBV. Further, captive reindeer may serve as reservoir hosts for pathogens circulating in local domestic, captive, and wild ruminant species and populations and arthropod vectors.

Serological evidence of Toxoplasma gondii and Neospora caninum infection in black-boned sheep and goats in southwest China

Toxoplasma gondii and Neospora caninum are two closely related protozoan parasites which can cause abortion and significant economic losses in sheep and goats. However, it is yet to know whether black-bone sheep and goats are infected with T. gondii and N. caninum in China. In the present investigation, the seroprevalence and risk factors of T. gondii and N. caninum infections in black-boned sheep and goats were investigated in Yunnan Province, subtropical southwest China between July and August of 2017. A total of 481 serum samples were tested for T. gondii antibodies using the Modified Agglutination Test (MAT), and 468 serum samples were examined for N. caninum antibodies by indirect Enzyme-Linked Immunosorbent Assay (iELISA). The overall seroprevalence of T. gondii in black-boned sheep and goats was 36.80% (177/481, 95% CI 32.49-41.11), and 40 out of 468 serum samples were N. caninum-seropositive (8.55%, 95% CI 6.02-11.08). There was significant difference in the seroprevalence of T. gondii infection in different regions (χ² = 19.869, df = 2, P<0.01). As for the seroprevalence of N. caninum infection, region (χ² = 8.558, df = 2, P<0.05), age (χ² = 16.631, df = 3, P < 0.01), gender (χ² = 11.219, df = 1, P < 0.01) and species (χ² = 8.673, df = 1, P < 0.01) were the risk factors. In addition, the seroprevalence of coinfection of T. gondii and N. caninum in black-boned sheep and goats was 3.63% (17/468, 95% CI 1.94-5.32). To our knowledge, this is the first report of T. gondii and N. caninum seroprevalence in black-boned sheep and goats in China, which provided base-line data for the execution of control strategies and measures against T. gondii and N. caninum infection in black-boned sheep and goats.

Meta-analysis of the prevalence and risk factors associated with bovine neosporosis

Neospora caninum is one of the main infectious agents that cause reproductive disorders in cattle. However, knowledge about the prevalence and causal factors of bovine neosporosis is needed in order to establish control measures. The purpose of this study was to estimate the pooled prevalence and determine the risk factors of bovine neosporosis using meta-analytic methods. Searches for data on N. caninum seroprevalence and potential risk factors were conducted in the PubMed, LILACS, and SciElo databases. The random effects model was used for the meta-analysis of the included studies. The pooled prevalence of N. caninum in cattle was 24% (95% confidence interval (CI), 19-29) in North and Central America, 24% (95% CI, 20-28) in South America, 18% (95% CI, 14-21) in Asia, 15% (95% CI, 12-18) in Europe, 13% (95% CI, 11-16) in Africa, and 8% (95% CI, 4-14) in Oceania. A significant correlation was found between N. caninum infection and abortion in cows (odds ratio (OR) = 2.66, 95% CI, 1.97-3.59). The following risk factors were signicantly associated with N. caninum seroprevalence: presence of dogs on the farm (OR = 2.84; 95% CI, 1.40-5.80) and the type of cattle production system, with dairy cattle being more susceptible to bovine neosporosis (OR = 1.60; 95% CI, 1.16-2.19) than beef cattle. The adoption of measures to prevent the dissemination of N. caninum in cattle herds is suggested, aiming to reduce the economic losses incurred to the dairy and beef industry.

Evaluation of abortions spontaneously induced by Neospora caninum and risk factors in dairy cattle from Lima, Peru

Our objective was to identify the direct and indirect presence of Neospora caninum in dairy cattle and their aborted fetuses from Lima, Peru. A total 219 blood samples obtained from dairy cattle with records of spontaneous abortion were collected to detect antibodies against N. caninum in serum with indirect ELISA and search for risk-factor associations. 68 fetal aborted tissue samples of these cows were analyzed by PCR, indirect ELISA and histopathology assay to detect N. caninum presence. The prevalence ratio (PR) and 95% confidence intervals (CI) were estimated. Univariate analysis was performed using the chi-squared test. Among the 68 aborted fetuses collected, 10 (15%) were positive in at least two diagnostic tests. Among 219 serum samples, 46.6% (95% CI: 40.0%-53.3%) were positive. Cows with 4 years or older (PR: 7.10; 95% CI: 4.89-10.67) and multiparous (PR: 1.76; 95% CI: 1.11-2.80) were found to be more likely to possess N. caninum antibodies. This study detects presence of N. caninum in dairy cattle and their aborted fetus from Lima valley, suggesting biosecurity management improve to neosporosis control.

Prevalence and risk factors of Neospora caninum infection in ovine flocks of central-western Mexico

This study, carried out in 13 sheep flocks of central-western Mexico, aimed to identify the prevalence of anti-N. caninum antibodies, to develop a risk analysis of the infection and to estimate the prevalence of parasite DNA in blood. A total of 368 serum and blood samples were subjected to ELISA and PCR tests, respectively, and the association between the prevalence of antibodies and some management factors was estimated. The overall prevalence of anti-N. caninum antibodies was 13.5% [50/368; 95% confidence interval (CI) 10-17], ranging from 2.7 to 90% per flock, and 92% of the farms had seropositive animals. In ewes the prevalence was 14% (48/348, 95% CI 10-17) and in rams 10% (2/20; 95% CI 1- 33). The mean prevalence of Neospora DNA in blood was 27% (99/368, 95% CI 22-31), implying a range between 16 and 82%. In rams, the prevalence was 5% (1/20 95% CI 2-26), while in ewes it was 28% (98/348, 95% CI 23-33). The agreement between the tests was k = 0.19. The presence of other domestic animal species in the farms [odds ratio (OR) 4.4] and the consumption of placental debris, fetuses and stillborn lambs by dogs living in the farms (OR 5.8) were demonstrated to be risk factors.

Seroprevalence of Toxoplasma gondii and Neospora caninum infections and associated factors in sheep from Costa Rica

The presence of antibodies against Toxoplasma gondii and Neospora caninum were analyzed in 392 sheep sera from ten Costa Rican ovine flocks using indirect immuno-enzymatic assays. Additionally, general information about sheep management, environment, and clinical reproductive disorders was assessed through a questionnaire to inquire factors related to these apicomplexan parasites. A total of 161 (41.1%) serum samples reacted positive to T. gondii, 43 (10.9%) to N. caninum and 26 (6.63%) to both parasites. Toxoplasma gondii serorreactors were detected in all the analyzed flocks (100.0%), meanwhile N. caninum antibodies were found in nine flocks (90%), from the six Costa Rican regions. Factors associated with T. gondii were the co-presence of cattle (OR = 5.06; C.I.95%; 2.08-12.30; p: <0.001), grey foxes (Urocyon cinereoargenteus) and opossums (Didelphis marsupialis) (OR = 2.44; C.I.95%; 1.50-3.95; p: <0.001) inside or around the farms, and the presence of peccaries (Tayassu sp.) (OR = 0.35; C.I.95%; 0.16-0.74; p: 0.0058) was a variable associated with N. caninum seropositivity. The obtained results of T. gondii and N. caninum infections in sheep flocks from Costa Rica should be considered for the proper prevention and control strategies against these apicomplexan abortive parasites.

First report on the sero-epidemiology of Toxoplasma gondii infection in German roe deer (Capreolus capreolus)

While the roe deer (Capreolus capeolus) is the most important game species in Germany and its venison is popular, there is limited knowledge about the prevalence of Toxoplasma gondii in this animal population in the country, and in wild ungulates in Germany generally. Between 2013 and 2015, we collected 295 blood samples from roe deer belonging to a central German population. Sera were analysed using a modified agglutination test (MAT, cut-off 1:20), and antibodies were detected in 86 of the 295 samples (29%). Seroprevalence values differed significantly between the different age classes, with antibodies more frequently observed in adults. In contrast, seroprevalence did not differ significantly between the sexes or collection years. Venison is frequently consumed raw or undercooked and may be a potential source of human infection with T. gondii.

Ocorrência de anticorpos anti-Toxoplasma gondii e anti-Neospora caninum em ovinos com distúrbios reprodutivos e fatores de risco

RESUMO: Objetivou-se avaliar a ocorrência, sinais clínicos e fatores de risco associados a soropositividade para Toxoplasma gondii e Neospora caninum em ovinos. Foram utilizados 294 animais com histórico de distúrbios reprodutivos de 28 fazendas do estado de São Paulo, Brasil, diagnosticados através da imunofluorescência indireta (1:64 e 1:50). A ocorrência de T. gondii foi de 29,9% (88/294) e de N. caninum 18% (53/294), sendo 3,7% (11/294) dos ovinos soropositivos para ambos. Observou-se com maiores chances à infecção pelo T. gondii: ovinos mestiços (p=0,04), Santa Inês (p=0,006), fornecimento de pastagem (p<0,001) ou associada a concentrado (p<0,001), uso exclusivamente de monta natural (p=0,002, OR=2,28 e IC95%=1,37-3,79) e a presença de aves nas propriedades (p=0,001). Na infecção por N. caninum essa chance aumentou em: fêmeas (p=0,031), propriedades sem aprisco (p<0,001) e sistema de criação semi-intensivo (p<0,001). Em relação ao histórico de problemas reprodutivos, ovelhas infectadas pelo N. caninum e T. gondii apresentaram redução da chance de apresentarem abortamento (p=0,044) e repetição de estro (p=0,025) respectivamente. O T. gondii esteve mais presente sorologicamente que o N. caninum em ovinos com histórico de distúrbios reprodutivos e apesar de suas semelhanças, diferiram epidemiologicamente em aspectos relacionados as características da criação como raça, sexo, sistema de criação, tipo de alimentação e manejo reprodutivo.

Seroprevalence and risk factors of Neospora caninum infection among domestic sheep in Henan province, central China

This study aimed to determine the frequency of antibodies to Neospora caninum in domestic sheep raised in Henan province, central China. Serum samples from 779 domestic sheep were collected from March 2015 to May 2016, and antibodies to N. caninum were evaluated using an enzyme-linked immunosorbent assay (ELISA). The results showed an overall IgG positive rate of 7.32% (57/779). The risk factors significantly related to seropositivity to N. caninum in sheep were the age, the presence of dogs, and the rearing system. This is the first report of N. caninum infection and associated risk factors in domestic sheep in central China.

Neospora caninum in properties in the west region of Paraná, Brazil: prevalence and risk factors

Abstract Neospora caninum is a heteroxenous protozoa, whose definitive hosts are canids and intermediate hosts are herbivores, and is of great importance in cattle. The objectives of this study were to determine the prevalence of N. caninum in dairy cattle and dogs, to detect the presence of the protozoa at the molecular level in aborted fetuses, and to identify the risk factors associated with infection in properties in the western region of the state of Paraná. For this study, 600 bovine serum samples from 60 properties, 163 canine serum samples from 52 properties and 17 bovine fetuses from nine properties were collected. Data were collected using an epidemiological questionnaire to verify the risk factors. Serum samples were analyzed using the indirect fluorescent antibody test. Fetal tissues were analyzed using polymerase chain reaction and subsequent DNA sequencing. Of the bovine samples, 23.67% were positive for N. caninum. Among the canine samples, 11.66% were positive for N. caninum. Risk factors in cattle were history of abortion, low milk production, extensive breeding, and Jersey breed (p<0.05). Protozoan DNA was detected in 52.94% of the 17 fetuses and the sequencing presented high similarity with N. caninum.

A new lyophilized tachyzoite based ELISA to diagnose Besnoitia spp. infection in bovids and wild ruminants improves specificity

Recent studies have reported that routinely used whole or soluble Besnoitia besnoiti tachyzoite (TZ) extract-based ELISAs potentially give rise to a high number of false-positive results, which may compromise control and the epidemiological studies of bovine besnoitiosis. Thus, western blot (WB) has been recommended as a confirmatory test. In the present study, a new ELISA test that employs lyophilized tachyzoites for the first time (BbSALUVET ELISA 2.0) was developed and validated with cattle sera (n=606) under a worst-case scenario. False positive and false negative, soluble TZ extract-based BbSALUVET ELISA 1.0 reactors were overrepresented, and WB was used as the reference test. One commercial test (PrioCHECK Besnoitia Ab 2.0, which employs whole TZ extract) and a recently developed membrane-enriched ELISA (APure-BbELISA) were also tested. The three ELISAs showed high AUC values (>0.9). However, the best diagnostic performance corresponded to the BbSALUVET ELISA 2.0 and the APure-BbELISA [(92% sensitivity (Se) and 98% specificity (Sp)] followed by PrioCHECK Besnoitia Ab 2.0 (88% Se, 98% Sp, and 4.5% doubtful results). In addition, the BbSALUVET ELISA 2.0 was validated with wild ruminant sera, and excellent performance (96% Se, 97% Sp, and 4% doubtful results) was obtained again. A different antigenic composition of the lyophilized tachyzoites, compared with whole or soluble tachyzoite extracts, may be responsible for the improved diagnostic performance. This study proposes the use of the BbSALUVET ELISA 2.0 in cattle prior to entry to herds free of the disease and in valuable samples prior to a selective culling without the need of a confirmatory Western Blot test in positive samples due to its excellent specificity.

Anti-Toxoplasma gondii antibodies in beef cattle slaughtered in the metropolitan region of Belém, Brazilian Amazon

Abstract The relevance of consuming raw or undercooked beef in the transmission of toxoplasmosis is unclear due to the high resistance of cattle to infection. However, this possibility needs to be considered in endemic areas, such as the Amazon, where the consumption of beef is frequent. The objective of this study was to determine the frequency of anti-Toxoplasma gondii IgG antibodies in beef cattle slaughtered in the metropolitan region of Belem, Pará state, Brazil. Blood samples were collected from 500 animals of both genders in a licensed slaughterhouse in Belém. Anti-T. gondii IgG antibodies were detected by an indirect immunofluorescence assay (IFA) with a cut-off titer of 1:64. Anti-T. gondii antibodies were found in 203 animals (40.6%), with a titer of 64 in 112 animals (55.2%), 128 in 68 animals (33.5%), 256 in 15 animals (7.4%), 512 in 5 animals (2.5%), and 1,024 in 3 animals (1.4%). No significant difference was observed between males and females (p > 0.05). The high frequency of anti-T. gondii antibodies observed in beef cattle slaughtered in Belém indicates that the meat of these animals may be an important source of infection for humans and carnivorous domestic animals when inadequately cooked beef is consumed.

Seroprevalence of Neospora caninum infection in farmed sika deer (Cervus nippon) in China

Neospora caninum is a worldwide protozoan that can induce neuromuscular disease in dogs and reproductive failure in domestic and wild ruminants. The objective of the present investigation was to determine the seroprevalence of N. caninum infection in farmed sika deer in China as little is known of this host-parasite relationship. A total of 1800 serum samples were collected during 2013 and 2014 from farmed sika deer in the major production areas of Liaoning, Jilin and Heilongjiang provinces.Assay by ELISA for N. caninum antibodies indicated a seroprevalence of 13.6% in 2013 and 15.8% in 2014, varying in different regions from 9.5% to 27.5%. Statistical analysis revealed that prevalence in animals aged >4 years (20.4%) was significantly higher than in the age ranges <2 years (9.6%) and 2-4 years (11.4%) (P<0.01). Moreover, sika deer in herds with a history of miscarriage (41.9%) had a significantly higher seroprevalence than in those without (12.6%) (P<0.01). The present survey confirms that N. caninum does occur in farmed sika deer in China and provides base-line data for the design and evaluation of measures for its control and prevention in this host.

Seroprevalence of Toxoplasma gondii in wild boars, red deer and roe deer in Poland

Little is known about the prevalence of Toxoplasma gondii in wild life, particularly game animals in Poland. Meat juice collected during the 2009/2010 and 2010/2011 hunting seasons from 552 red deer (Cervus elaphus), 367 wild boars (Sus scrofa) and 92 roe deer (Capreolus capreolus) was tested for T. gondii antibodies using the multi-species ID Screen Toxoplasmosis Indirect kit (IDvet, Montpellier, France). Antibodies to T. gondii were detected in 24.1% of red deer (95% CI: 20.7%, 27.8%), 37.6% of wild boar (95% CI: 32.8%, 42.7%) and 30.4% of roe deer (95% CI: 22.0%, 40.5%). To the authors' best knowledge, this is the first epidemiological report of T. gondii prevalence in red deer, roe deer and wild boars in Poland. T. gondii is present in wildlife animal tissues and consumption of the game may be a potential source of infection for humans.

A review of neosporosis and pathologic findings of Neospora caninum infection in wildlife

Neospora caninum is an apicomplexan parasite that is the etiologic agent of neosporosis, a devastating infectious disease regarded as a major cause of reproductive loss in cattle and neuromuscular disease in dogs worldwide. This protozoan pathogen is maintained in the environment by a heteroxenous life cycle that involves a definitive canid host and a wide range of intermediate hosts. In recent years, a number of wildlife species have been investigated for their possible involvement in the N. caninum life cycle and many have been implicated as intermediate hosts. However, in many instances these studies have utilized serological and molecular techniques to detect infection in clinically normal animals, and investigation of possible associated morbidity, mortality, and pathology has been neglected. As such, the occurrence and importance of Neospora-associated disease in wildlife species are unknown. In order to improve our understanding of the significance of N. caninum infection in nondomestic species, the present review provides an up-to-date summary of clinical neosporosis and N. caninum-associated pathologic lesions in naturally and experimentally infected wildlife species. We provide a list of all free-ranging and captive wildlife species identified with N. caninum infection to date using currently available diagnostic tools. The advantages and disadvantages of diagnostic methods in wildlife are addressed in order to recommend optimal diagnosis of confirming N. caninum infection and neosporosis in nondomestic species. Although current data would suggest that N. caninum infection does not adversely impact wildlife populations, there is a need for greater international uniformity in the diagnosis of N. caninum infection and neosporosis in nondomestic species in order to assess the true consequences of parasite infection.

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.

Occurrence of anti-Toxoplasma gondii antibodies in meat and dairy goat herds in Rio Grande do Norte, Brazil

Toxoplasmosis is caused by Toxoplasma gondii, which is the main causative agent of abortion in small ruminants. Goats are among the animals that are most susceptible to this protozoon, and the disease that it causes leads to significant economic losses and has implications for public health, since presence of the parasite in products of goat origin is one of the main sources of human infection. Because of the significant economic impact, there is an urgent need to study the prevalence of T. gondii infection among goats in Sertão do Cabugi, which is the largest goat-producing region in Rio Grande do Norte. In the present study, the ELISA assay was used to test 244 serum samples from nine farms, located in four different municipalities in the Sertão do Cabugi region, which is an important goat-rearing region. The results showed that the prevalence of anti-T. gondii antibodies was 47.1% and that there was a significant association between positivity and the variables of age (≥ 34 months), location (Lajes, Angicos and Afonso Bezerra) and farm (all the farms). The avidity test was applied to all the 115 ELISA-positive samples to distinguish between acute and chronic infection. One hundred and three samples (89.6%) displayed high-avidity antibodies, thus indicating that most of the animals presented chronic infection, with a consequent great impact on the development of the goat production system and a risk to human health.

Neospora caninum infection as a cause of reproductive failure in a sheep flock

Neospora caninum has been detected only sporadically in cases of ovine abortion, and it has therefore traditionally been considered as an unimportant parasite in small ruminants. This study was carried out with the aim of identifying the pathogen causing serious reproductive problems on a commercial sheep farm. Sera from all rams and ewes tested negative for antibodies against Border disease virus, Schmallenberg virus and Coxiella burnetii, and infections by these agents were therefore ruled out. Nevertheless, seropositivity to N. caninum and/or Toxoplasma gondii was detected, although the seroprevalence was higher in the case of N. caninum. The percentage of lambings and the number of lambs per dam were significantly lower in ewes that were seropositive to N. caninum while no effect on these parameters was detected in ewes that were seropositive to T. gondii. There was also no evidence of infection by T. gondii in the foetal/lamb tissues analyzed by PCR and/or immunohistopathological techniques. On the contrary, the DNA of N. caninum was detected in 13 out of 14 foetuses/lambs descendant from dams seropositive to this parasite. Characteristic lesions caused by N. caninum and/or its antigen were also detected. Genotyping of the N. caninum DNA revealed only two closely related microsatellite multilocus genotypes. The results clearly demonstrate that infection by N. caninum was the cause of the low reproductive performance of this sheep flock.

Infectious pathogens potentially transmitted by semen of the black variety of the Manchega sheep breed: Health constraints for conservation purposes

Conservation of genetic resources from endangered breeds may be conducted through germinal banks. Preservation of healthy samples is paramount to avoid preserving pathogens shed with germinal products. The black variety of Manchega sheep (BMS), and endangered breed endemic to south-central Spain, is the subject of a conservation program; a germinal bank has been recently established. However, several pathogens circulating in BMS flocks may be shed with semen and threaten BMS preservation. Therefore, we investigated the sanitary status of BMS flocks and semen samples from 4 of the 17 flocks in which this variety is bred worldwide. A serological screening for Maedi-Visna virus, bluetongue virus, Pestivirus spp., Brucella spp., Coxiella burnetii, Chlamydophila spp., Mycobacterium tuberculosis complex, Mycobacterium avium paratuberculosis, Anaplasma spp., Mycoplasma agalactiae, Toxoplasma gondii and Neospora caninum was performed to assess for pathogens potentially shed by semen. Semen samples from 11 of the 35 BMS rams and 4 samples from coexisting rams of the white variety (WMS) were analyzed by PCR to detect Maedi-Visna virus, C. burnetii, Anaplasma marginale, Anaplasma phagocytophilum and T. gondii. Maedi-Visna virus RNA was detected in 3 semen samples (2 BMS and 1 WMS) while C. burnetii DNA was detected in 3 samples from WMS rams. Pathogens that can be transmitted by semen were present in BMS flocks, and Maedi-Visna virus and C. burnetii showed the highest potential for transmission by artificial insemination. Our results point to the need of testing semen samples kept for conservation purposes of BMS before using them for artificial insemination.

Toxoplasma gondii in Cattle, Camels and Sheep in Isfahan and Chaharmahal va Bakhtiary Provinces, Iran

BACKGROUND

Toxoplasma gondii is a zoonotic parasite, which is assumed to have cosmopolitan distribution.

OBJECTIVES

Adopting a cross-sectional study design the current research aimed to determine the occurrence of the parasite in cattle, camels and sheep in Isfahan and Chaharmahal va Bakhtiary provinces of Iran.

MATERIALS AND METHODS

Animals in the field and those brought for slaughter at abattoirs were included. Blood samples were randomly collected from animals and investigated by polymerase chain reaction (PCR).

RESULTS

T. gondii infections were detected in 0.00%, 6.60% and 17.9% of the sample cattle (n = 155), camels (n = 122) and sheep (n = 95) respectively. Sheep were more frequently affected in Chaharmahal va Bakhtiary (33.33%) compared to Isfahan (8.47%) (P = 0.005, 95%; CI = 6.88-43.35). No statistically significant difference was observed in infection prevalence between camels and sheep; and between the different sex categories in both camels and sheep.

CONCLUSIONS

Evidence of T. gondii occurrence in sheep and camels was provided in the provinces under study. There is a need to investigate the potential risk factors of zoonotic infections. Furthermore, animal health and production losses caused by the parasite; and associated zoonotic implications in the area under study need to be explored.