Detection of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii in horses from Costa Rica

Optimization of a Conventional Assay into SYBR Green Real-Time PCR for the Detection of the Nc5 Segment from Neospora caninum

PURPOSE

The aim of the present study was to establish a SYBR Green-based real-time PCR assay for detection of the Nc5 segment from the Neospora caninum genome.

METHODS

The oligonucleotides sequences targeting the Nc5 gene previously reported and designed in-house were validated. Two Primer sets were evaluated and tested in four different combinations. The NP7/NP10 assay was selected and reaction conditions optimized. Efficiency, analytical sensitivity, precision and specificity were assessed. The assay was evaluated in triplicate, in three independent PCR runs performed by two technicians to generate robust results.

RESULTS

The standard curve determined by tenfold serial dilutions (1 to 1 × 10-7) established a reaction efficiency (E) of 102.34%, a correlation coefficient (R2) of 0.999 and a slope of -3.267. LOD of the real-time PCR assay was 0.456 tachyzoites DNA per reaction, as compared to 45.62 for the conventional method. SYBR green real-time PCR was 100 times more sensitive than the conventional method. Precision analysis showed 100% intra- and inter-assay repeatability at the minimum detection limit. The mean assay coefficient of variation (CV%) was 4.19% and standard deviation (SD) 1.67%. No significant differences between the means of Cq in the replicates and technicians (P > 0.05) was found, indicating that the assay is robust and accurate. The applicability of the assay was tested and N. caninum DNA was detected in milk, blood, amniotic fluid, placenta and different tissue samples.

CONCLUSION

The protocol had high specificity, confirmed by melting curve analysis and no cross-reactions with other tested microorganisms. The SYBR Green-based PCR protocol standardized in this study is a highly sensitive and specific method, reproducible and applicable for the detection of N. caninum in different biological samples.

Seroepidemiological study of Neospora caninum in equids using c-ELISA in Erbil Province, Iraq

Equine neosporosis is an intracellular protozoan disease with a global distribution, affecting a diverse range of warm-blooded animals. Neospora caninum Dubey, Carpenter, Speer, Topper et Uggla, 1988 is associated with foetal loss, neurological disease and abortion in equids. No information was available regarding equine N. caninum infection among equids in Iraq. Thus, the aim of this study was to determine the prevalence rate of N. caninum in equines by using a competitive enzyme-linked immunosorbent assay (c-ELISA). A total of 329 blood samples randomly selected from equines, comprising 268 horses and 61 donkeys were examined. The seroprevalence rate of N. caninum was determined as 46% (28/61) for donkeys and 24% (64/268) for horses. The prevalence of N. caninum indicated a significantly higher risk of infection in donkeys compared to horses (P < 0.001). However, the odds of N. caninum infection in draught equids were 8.2 times greater than other equids with a significant difference (P < 0.001). The current study revealed no significant differences in the prevalence of N. caninum across various genders, breeds, clinical statuses, disease histories and among equids that had contact with dogs. While outdoor feeding and mixed (grazing), showed a significant difference (P = 0.003) and (P = 0.75), respectively, in the presence of antibodies against N. caninum compared to indoor feeding (stable). Moreover, the odds of infection in equids with a history of late abortion were 4.8 times higher than those without such a history of abortion (2.20-10.56) with statistical significance (P < 0.001).

Molecular identification of Sarcocystis neurona in tissues of wild boars (Sus scrofa) in the border region between Brazil and Uruguay

Sarcocystis neurona, owing to its clinical importance in domestic animals, is currently one of the most studied agents, presenting a wide range of intermediate hosts that have not yet been described, mainly in wild fauna. Thus, the aim of this study was to describe the detection and molecular detection of S. neurona by amplification of the 18S rRNA region in the tissues of wild boars killed by boar control program in border Brazil Uruguay. A total of 79 samples of DNA from wild boar tissues from the LADOPAR/UFSM sampling bank were used, with Nested-PCR reactions being performed for amplification of the 18S rRNA region and the expected final product of 290 bp. Subsequently, the positive samples were subjected to restriction fragment length polymorphism (RFLP) technique with the restriction enzymes DdeI and HPAII. A second semi-Nested reaction was performed to obtain a larger sequence of nucleotides with amplification of the 18S region and the expected final product of 500 bp for S. neurona and Nested amplification ITS1 with product final of 367 pb. In 32 samples, it was possible to detect S. neurona both by nested Nested-PCR reaction and RFLP, and the presence of the agent was confirmed by sequencing, corresponding to 40.51% of the total tissues evaluated. This is the first report of the occurrence of this species of Sarcocystis in wild boars, and further studies evaluating the role of these animals as intermediate hosts, and in the epidemiology of this protozoan are necessary, as well as verifying the risk factors for infection.

Seroprevalence and risk factors for Neospora spp. infection in equine in Egypt

Neospora infections in equine are associated with reproductive disorders and neurological diseases. Nevertheless, Egypt has no epidemiological information on this parasite in equine. This study determined the prevalence of Neospora spp. infection in 325 equines from three Egyptian governorates located at Northern Egypt using cELISA. The prevalence of antibodies against Neospora spp. was 19% (95% CI: 14.09-25.05) in horse, 34.1% (95%CI: 24.92-44.69) in donkey and 26.7% (95% CI: 15.97-41.04) in mule. In comparison to horse, donkey had a considerably higher chance of contracting Neospora spp. infection (OR = 1.80, 95% CI: 0.78-4.13; P = 0.016). The risk was also higher in freely grazing animals (OR = 3.49, 95% CI: 0.95-12.78; P = 0.059). Moreover, yearling animals (12-24 months) (OR = 5.03, 95% CI: 1.51-16.80; P = 0.009) and those with natural breeding (OR = 11.80, 95% CI: 3.24-42.99, P < 0.0001) and a history of early abortion (OR = 7.04, 95% CI: 3.01-16.47; P < 0.0001) also showed a greater risk of seropositivity. The risk of Neospora infection increased significantly in equines contacted with dogs (OR = 5.16, 95% CI: 1.76-15.10; P = 0.003). This the first serological study to determine the seroprevalence of Neospora spp. in equine in Egypt. Further studies are necessary to identify the species of Neospora and to understand the role of above-mentioned risk factors in spreading of infection.

Equine Protozoal Myeloencephalitis

Advances in the understanding of equine protozoal myeloencephalitis (EPM) are reviewed. It is now apparent that EPM can be caused by either of 2 related protozoan parasites, Sarcocystis neurona and Neospora hughesi, although S neurona is the most common etiologic pathogen. Horses are commonly infected, but clinical disease occurs only infrequently; the factors influencing disease occurrence are not well understood. Epidemiologic studies have identified risk factors for the development of EPM, including the presence of opossums and prior stressful health-related events. Attempts to reproduce EPM experimentally have reliably induced antibody responses in challenged horses, but have not consistently produced neurologic disease. Diagnosis of EPM has improved by detecting intrathecal antibody production against the parasite. Sulfadiazine/pyrimethamine (ReBalance) and the triazine compounds diclazuril (Protazil) and ponazuril (Marquis) are effective anticoccidial drugs that are now available as FDA-approved treatments for EPM.

Seroepidemiology of Sarcocystis neurona and Neospora spp. in horses, donkeys, and mules from Colombia

Sarcocystis neurona and Neospora spp. are related protozoa that can cause equine protozoal myeloencephalitis (EPM). The present study aimed to determine the frequency of antibodies to these parasites in 649 equids (351 horses, 267 donkeys, and 31 mules) from six departments in the North and Northwest of Colombia. For this purpose, the indirect fluorescent antibody test (IFAT) was used for detecting antibodies against S. neurona and Neospora spp. with a cut-off point of 1:20 and 1:50, respectively. A binomial logistic regression model was selected to predict variables associated with exposure. The frequency of anti-S. neurona antibodies was 14.24% (95% CI: 10.84-18.44) for horses, 2.99% (95% CI: 1.39-6.04) for donkeys, and 16.13% (95% CI: 6.09-34.47) for mules. The risk for S. neurona infection was significantly lower in donkeys (OR: 0.18 [0.08-0.38]; p<0.001) than horses and mules, and higher in animals with a poor body condition (OR: 2.82 [1.45-6.05]; p<0.05). Additionally, older animals (>12y) had a higher risk of seropositivity (OR: 5.26 [1.88-19.1]; p<0.05), as well as animals that inhabit climatic conditions associated with tropical very dry forest (OR: 1.85 [1.01-3.51]; p<0.05). Córdoba and Antioquia departments presented the highest seropositivity to S. neurona with 13.01 and 8.3%, respectively. The frequency of anti-Neospora spp. antibodies was 1.42% (95% CI: 0.52-3.48) for horses, 1.12% (95% CI:0.29-3.52) for donkeys and 0% (95%, CI: 0-0) for mules. Atlántico was the state with the highest seropositivity to Neospora spp. (10%). No risks associated with Neospora spp. infection were found. These findings allow us to conclude that equids from these regions of Colombia are exposed to S. neurona, but antibodies to Neospora spp. are uncommon. Further studies are necessary to explore the presence of these two agents in other areas of the country. In addition, we need to prove the importance of the above-mentioned risk factors over the susceptibility of horses to these protozoal agents and the epidemiological impact of these underdiagnosed coccidia.

Global seroprevalence of Neospora spp. in horses and donkeys: A systematic review and meta-analysis

Neospora infections due to Neospora caninum and N. hughesi are prevalent among equids of the world. The disease may affect reproductive and neurological consequences. The present systematic review and meta-analysis was performed to evaluate the global Neospora seroprevalence among horses and donkeys. A number of 57 out of 1575 total retrieved studies were included by searching the PubMed, Scopus, Science Direct, Web of Science and ProQuest. A total of 25,783 horses and 4377 donkeys were examined serologically, yielding a weighted seroprevalence of 13.46 % (95 % CI: 10.26 %-17.42 %) globally. Subgroup analysis revealed that there were statistically significant differences in the overall prevalence of Neospora spp. in the examined animals according to year, continent, WHO region, country, host, and diagnostic method. Age and sex in horses as well as sex in donkeys were significantly associated with the Neospora seroprevalence (P < 0.001). Our findings showed a relatively high exposure to Neospora spp. in horses and donkeys worldwide. Considering the possible economic impact, as well as the importance in animal health, more studies are needed to clarify the species causing equine neosporosis, correlate serological findings with clinical outcomes and assess the risk factors, in order to define adequate prevention and control strategies.

Toxoplasma gondii infections in horses, donkeys, and other equids: The last decade

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, and genetic diversity of T. gondii in horses, donkeys and other equids in the past decade. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

In silico identification of immunotherapeutic and diagnostic targets in the glycosylphosphatidylinositol metabolism of the coccidian Sarcocystis aucheniae

Meat of the South American camelids (SACs) llama and alpaca is an important source of animal protein and income for rural families in the Andes, and a product with significant growth potential for local and international markets. However, infestation with macroscopic cysts of the coccidian protozoon Sarcocystis aucheniae, a parasitosis known as SAC sarcocystosis, significantly hampers its commercialization. There are no validated methods to diagnose the presence of S. aucheniae cysts other than carcass examination. Moreover, there are no available drugs or vaccines to cure or prevent SAC sarcocystosis. Identification of relevant molecules that act at the host-pathogen interface can significantly contribute to the control of this disease. It has been shown for other pathogenic protozoa that glycosylphosphatidylinositol (GPI) is a critical molecule implicated in parasite survival and pathogenicity. This study focused on the identification of the enzymes that participate in the S. aucheniae GPI biosynthetic pathway and the repertoire of the parasite GPI-anchored proteins (GPI-APs). To this aim, RNA was extracted from parasite cysts and the transcriptome was sequenced and translated into amino acid sequences. The generated database was mined using sequences of well-characterized GPI biosynthetic enzymes of Saccharomyces cerevisiae and Toxoplasma gondii. Eleven enzymes predicted to participate in the S. aucheniae GPI biosynthetic pathway were identified. On the other hand, the database was searched for proteins carrying an N-terminal signal peptide and a single C-terminal transmembrane region containing a GPI anchor signal. Twenty-four GPI-anchored peptides were identified, of which nine are likely S. aucheniae-specific, and 15 are homologous to membrane proteins of other coccidians. Among the latter, 13 belong to the SRS domain superfamily, an extensive group of coccidian GPI-anchored proteins that mediate parasite interaction with their host. Phylogenetic analysis showed a great degree of intra- and inter-specific divergence among SRS family proteins. In vitro and in vivo experiments are needed to validate S. aucheniae GPI biosynthetic enzymes and GPI-APs as drug targets and/or as vaccine or diagnostic antigens.

Toxoplasma gondii infection and toxoplasmosis in farm animals: Risk factors and economic impact

The protozoan parasite Toxoplasma gondii is a zoonotic parasite that can be transmitted from animals to humans. Felids, including domestic cats, are definitive hosts that can shed oocysts with their feces. In addition to infections that occur by accidental oral uptake of food or water contaminated with oocysts, it is assumed that a large proportion of affected humans may have become infected by consuming meat or other animal products that contained infective parasitic stages of T. gondii. Since farm animals represent a direct source of infection for humans, but also a possible reservoir for the parasite, it is important to control T. gondii infections in livestock. Moreover, T. gondii may also be pathogenic to livestock where it could be responsible for considerable economic losses in some regions and particular farming systems, e.g. in areas where the small ruminant industry is relevant. This review aims to summarize actual knowledge on the prevalence and effects of infections with T. gondii in the most important livestock species and on the effects of toxoplasmosis on livestock. It also provides an overview on potential risk factors favoring infections of livestock with T. gondii. Knowledge on potential risk factors is prerequisite to implement effective biosecurity measures on farms to prevent T. gondii infections. Risk factors identified by many studies are cat-related, but also those associated with a potential contamination of fodder or water, and with access to a potentially contaminated environment. Published information on the costs T. gondii infections cause in livestock production, is scarce. The most recent peer reviewed reports from Great Britain and Uruguay suggest annual cost of about 5-15 million US $ per country. Since these estimates are outdated, future studies are needed to estimate the present costs due to toxoplasmosis in livestock. Further, the fact that T. gondii infections in livestock may affect human health needs to be considered and the respective costs should also be estimated, but this is beyond the scope of this article.

Seroprevalence and risk factors of Toxoplasma gondii infection in horses in Jilin Province and Inner Mongolia Autonomous Region, northern China

Toxoplasmosis is caused by the protozoon Toxoplasma gondii that can infect almost all warm-blooded hosts including horses and humans. Horse meat is one of the most important meat products for human consumption. However, data on seroprevalence of T. gondii in horses intended for human consumption in Northern China is scarce. Thus, a total of 614 serum samples were collected from Jilin Province and Inner Mongolia Autonomous Region (IMAR) between 2015 and 2017, and were detected the seroprevalence for T. gondii by indirect hemagglutination assay test. In the prevalence study, the overall seroprevalence of T. gondii in horses was 17.92% (110/614) by IHA test, at the cut- off 1:64. Horses collected from Changchun (13.58%, P = 0.02) has a significantly lower seroprevalence than those from Meihekou City (21.72%) and Tongliao City (22.81%). Moreover, a significant difference of T. gondii seroprevalence was found between horses ages at less than 12 months (22.75%) and ≥12 months or higher (16.42%, P = 0.002). To our knowledge, this is the first report of seroprevalence of T. gondii in horses in Jilin and IMAR, Northern China. Logistic regression suggested that age and geographical location of horses were identified as risk factors. These findings will provide the useful data for controlling and preventing toxoplasmosis in horses and/or other hosts in China.

Fatores de risco associados à prevalência de anticorpos anti-Sarcocystis neurona, Neospora spp. e Toxoplasma gondii em equinos de Roraima, Amazônia

RESUMO: Amostras de sangue de 303 equinos provenientes de 56 propriedades do município de Rorainópolis, Roraima, foram avaliadas por Reação de Imunofluorescência Indireta (RIF) para pesquisa de anticorpos contra Sarcocystis neurona, Toxoplasma gondii e Neospora spp. Algumas amostras de soros positivos para Sarcocystis spp. foram avaliadas pelo Western Blotting (WB) utilizando antígenos crus de S. neurona. A partir dos resultados sorológicos, possíveis fatores de risco foram avaliados frente a variáveis individuais e de propriedade. A prevalência de anticorpos anti-Sarcocystis spp. foi estimada em 43,2% (37,6-49,0%), anti-Neospora sp. em 26,7% (21,9-32,2%) e anti-T. gondii de 18,5% (14,3-23,4%). Quatorze amostras (14/15) testadas por WB resultaram positivas para antígenos de S. neurona. Das propriedades, 76,8% (43/56) apresentaram pelo menos um equino positivo para Sarcocystis spp.; 69,6% (39/56) para Neospora spp. e 55,4% (31/56) para T. gondii. Dos equinos, 13 (4,3%) apresentarem anticorpos para os três agentes, 50 (16,5%) para Sarcocystis spp. e Neospora spp., 10 (3,3%) para Neospora spp. e T. gondii, e oito (2,6%) para Sarcocystis spp. e T. gondii. As variáveis associadas (P≤0,05) à presença de anticorpos foram: para Neospora spp. não pastejar em áreas alugadas, ausência de assistência veterinária na propriedade, sexo masculino, não estabular animais e plantel equino acima de 5 animais; enquanto para T. gondii foram o contato com felinos, animais da raça lavradeiro, animal estabulado, criação de bovinos na propriedade e plantel equino acima de 5 animais. Não houveram variáveis associadas a presença de anticorpos contra S. neurona. Relata-se no presente estudo a primeira detecção de anticorpos anti-S. neurona, Neospora spp. e T. gondii em equinos do estado de Roraima, localizado na Amazônia Setentrional Brasileira, ressaltando para a elevada frequência de fazendas com equinos soropositivos.

Protozoal coinfection in horses with equine protozoal myeloencephalitis in the eastern United States

Background

Infection by 2 or more protozoa is linked with increased severity of disease in marine mammals with protozoan encephalitis.

Hypothesis/Objectives

To assess whether horses with equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona also have evidence of infection with Neospora hughesi or Toxoplasma gondii. We hypothesized that horses with EPM would be more likely than horses with cervical vertebral stenotic myelopathy (CVSM) to be positive for antibodies to multiple protozoan parasites.

Animals

One hundred one horses with neurologic disease: 49 with EPM and 52 with CVSM.

Methods

Case review. Archived serum and cerebrospinal fluid (CSF) from 101 horses were examined. Inclusion criteria included neurologic disease, antemortem or postmortem diagnosis of EPM or CVSM, and availability of serological results or archived samples for testing. Additional testing for antibodies was performed on serum for T. gondii, as well as serum and CSF for N. hughesi.

Results

Horses with EPM were more likely than horses with CVSM to have positive immunologic results for S. neurona on serum (95.9% versus 76.9%, P = .0058), CSF (98.0% versus 44.2%, P < .00001), and serum : CSF titer ratio (91.8% versus 0%, P < .00001). Positive results for Neospora and Toxoplasma were uncommon, with total seroprevalence rates of 12.9% and 14.9%, respectively. The proportions of EPM cases testing positive for Neospora and Toxoplasma (16% and 12%) were not different from the proportions of CVSM cases testing positive (10% and 17%, P = .31 and .47, respectively).

Conclusion

Results do not indicate an important role for protozoal coinfection in EPM in the eastern United States.

Seropositivity to Sarcocystis infection of llamas correlates with breeding practices

Production of llama (Lama glama) meat in rural communities of the Andean regions is largely affected by Sarcocystis spp. infection. Macroscopic cysts develop in muscles as a consequence of S. aucheniae parasitism, often resulting in meat downgrade or condemnation. Llama meat production is informal in Argentina but has broad perspectives for improvement, and would significantly benefit from the development of standardized control methodologies. This work analyzes whether the presence of anti-Sarcocystis spp. antibodies in llamas is influenced by factors such as geographic region and/or herd management practices. To this aim, an indirect ELISA was set up based on a ~23kDa soluble immunogenic protein fraction (Sa23), isolated from S. aucheniae macrocysts (Sa23-iELISA). Serum samples (n=507) were collected from llamas bred under three different conditions: (i) with no sanitation controls and in the presence of pastoral dogs by small producers of different localities of the Argentine Puna (Group I, n=237); (ii) with sanitation controls and no pastoral dogs, in fenced fields of an experimental agricultural station in the Argentine Puna (Group II, n=167); and (iii) with sanitation controls and no pastoral dogs in fenced fields of farms of the humid Pampas (Group III, n=103). Results of the Sa23-iELISA were expressed as percentages of positivity with respect to a reference Sarcocystis-positive serum. Notably, the percentage of sera that fell above the cut-off (31.5% positivity) in group (i) was significantly higher (p<0.001) than those of groups (ii) and (iii) (50% vs 23% and 26%, respectively). These results indicate that herd management practices constitute a critical risk factor for sarcocystiosis in llamas. Differences in these practices include feeding of dogs with raw Sarcocystis-infected llama meat, with the consequent maintenance of the parasite life cycle by the contamination of pastures and water with fecal-derived infective oocysts/sporocysts. Additionally, the itinerancy of llama herds in search for pastures and water sources possibly exposes animals to a higher number of infective foci. On the other hand, percentages of seropositive llamas kept under controlled conditions in the Puna or the humid Pampas were not significantly different, suggesting that climate, altitude, and/or pasture characteristics do not influence Sarcocystis-infection. Male gender and older age of llamas were found to be propensity factors for sarcocystiosis in llamas bred in La Puna under controlled conditions. Availability of diagnostic tools, as well as increased knowledge on the parasite and its epidemiology, will allow the design of control strategies for SAC sarcocystiosis.

Characterization of the zoonotic potential of Toxoplasma gondii in horses from Rio de Janeiro State

The aim of this study was to perform a survey on the prevalence of anti-Toxoplasma gondii antibodies in horses from Rio de Janeiro State, Brazil. From 2012 to 2013, a total of 624 blood samples were collected from horses from the eight regions comprising Rio de Janeiro State (Baixadas Litorâneas, Serrana, Norte Fluminense, Noroeste Fluminense, Centro-Sul, Metropolitana, Médio Paraíba, and Costa Verde). All sera samples were tested for anti-T. gondii antibodies by performing the modified agglutination test with a cut-off of 1:25. Positive serology for T. gondii was detected in 22.8% (142/624) of the horses studied. Seropositivity was detected in all regions sampled; furthermore, statistical significance was observed when all locations were compared at once. The Médio Paraíba region had the highest number of positive animals 54.76% (23/42) in the Bonferroni correction among Costa Verde, Centro Sul, Metropolitana, and Serrana (p<0.001). Seropositivity was 39.58% (38/96) in Norte Fluminense, which was the second most prevalent region. The results indicated that the T. gondii parasite is widely distributed in horses in Rio de Janeiro State and represents a risk to public and animal health. These findings emphasize the need to increase control and prevention of this disease in horses.

Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a Focus on Parasite Biology, Diagnosis, Treatment, and Prevention

Equine protozoal myeloencephalitis (EPM) remains an important neurologic disease of horses. There are no pathognomonic clinical signs for the disease. Affected horses can have focal or multifocal central nervous system (CNS) disease. EPM can be difficult to diagnose antemortem. It is caused by either of 2 parasites, Sarcocystis neurona and Neospora hughesi, with much less known about N. hughesi. Although risk factors such as transport stress and breed and age correlations have been identified, biologic factors such as genetic predispositions of individual animals, and parasite‐specific factors such as strain differences in virulence, remain largely undetermined. This consensus statement update presents current published knowledge of the parasite biology, host immune response, disease pathogenesis, epidemiology, and risk factors. Importantly, the statement provides recommendations for EPM diagnosis, treatment, and prevention.

The prevalence of antibodies to Toxoplasma gondii in horses in Changji Hui Autonomous Prefecture, Xinjiang, northwestern China

Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, which can infect warm-blooded animals and humans. The present study was performed to investigate the seroprevalence of T. gondii in horses in Xinjiang, northwestern China. A total of 637 blood samples were collected from seven regions in Changji Hui Autonomous Prefecture, Xinjiang in 2011 and assayed for T. gondiiantibodies using the modified agglutination test (MAT). Risk factors (age, gender, and region) related to seroprevalence were determined by a multivariate logistic regression analysis. A total of 200 horses (31.4%, 95% CI 27.79–35.00) were seropositive for T. gondii. Age, gender, and region present no association with seroprevalence (p>0.05) in the logistic regression analysis. The results indicated that T. gondii is widely prevalent in horses in Xinjiang, northwestern China, representing a serious threat to animal and human health. Therefore, more careful measures should be performed to control and prevent T. gondii infection in horses from Xinjiang, northwestern China.

Detection of Toxoplasma gondii DNA in horse meat from supermarkets in France and performance evaluation of two serological tests

In France, some cases of severe toxoplasmosis have been linked to the consumption of horse meat that had been imported from the American continent where atypical strains of Toxoplasma gondii are more common than in Europe. Many seroprevalence studies are presented in the literature but risk assessment of T. gondii infection after horse meat consumption is not possible in the absence of validated serological tests and the unknown correlation between detection of antibodies against T. gondii and presence of tissue cysts. We performed magnetic-capture polymerase chain reaction (MC-PCR) to detect T. gondii DNA in 231 horse meat samples purchased in supermarkets in France and evaluated the performance and level of agreement of the modified agglutination test (MAT) and enzyme-linked immunosorbent assay (ELISA) in the meat juices. The serological tests lacked sensitivity, specificity, and agreement between them, and there was no correlation with the presence of T. gondii DNA in horse meat, raising concerns about the reliability of T. gondii seroprevalence data in horses from the literature. T. gondii DNA was detected in 43% of horse meat samples but the absence of strain isolation in mice following inoculation of more than 100 horse meat samples suggests a low distribution of cysts in skeletal muscles and a low risk of T. gondii infection associated with horse meat consumption. However, to avoid any risk of toxoplasmosis, thorough cooking of horse meat is recommended.

An update on Sarcocystis neurona infections in animals and equine protozoal myeloencephalitis (EPM)

Equine protozoal myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control.

Exposure of free-living jaguars to Toxoplasma gondii, Neospora caninum and Sarcocystis neurona in the Brazilian Pantanal

Toxoplasma gondii, Neospora caninum and Sarcocystis neurona are related apicomplexan parasites that cause reproductive and neurological disorders in a wide range of domestic and wild animals. In the present study, the immunofluorescence antibody test (IFAT) was used to investigate the presence of antibodies against T. gondii, N. caninum and S. neurona in the sera of 11 free-living jaguars (Panthera onca) in two protected areas in the Pantanal region of Mato Grosso state, Brazil. Ten jaguars (90.9%) showed seropositivity for T. gondii, eight (72.7%) for S. neurona, and seven (63.6%) for N. caninum antigens. Our findings reveal exposure of jaguars to these related coccidian parasites and circulation of these pathogens in this wild ecosystem. To the best of our knowledge, this is the first serological detection of N. caninum and S. neurona in free-living jaguars.

Equine protozoal myeloencephalitis

Equine protozoal myeloencephalitis (EPM) can be caused by either of 2 related protozoan parasites, Sarcocystis neurona and Neospora hughesi, although S. neurona is the most frequent etiologic pathogen. Horses are commonly infected, but clinical disease occurs infrequently; the factors influencing disease occurrence are not well understood. Risk factors for the development of EPM include the presence of opossums and prior stressful health-related events. Attempts to reproduce EPM experimentally have reliably induced antibody responses in challenged horses but have not consistently produced acute neurologic disease. Diagnosis and options for treatment of EPM have improved over the past decade.

Prevalence of antibodies to Sarcocystis neurona and Neospora hughesi in horses from Mexico

Equine protozoal myeloencephalitis (EPM) is a debilitating disease of horses caused by Sarcocystis neurona and Neospora hughesi. Sera from 495 horses in Durango State, Mexico were tested for anti-protozoal antibodies using enzyme-linked immunosorbent assays (ELISAs) based on major surface antigens of these two parasites. Antibodies to S. neurona were detected in 240 (48.5%) of the 495 horse sera tested with the rSnSAG2/4/3 trivalent ELISA. Multivariate analysis showed that exposure to S. neurona was associated with age, feeding grains and crops, and small herd size. Antibodies to N. hughesi were found in 15 (3.0%) of the 495 horse sera tested with the rNhSAG1 ELISA and confirmed by Western blot of N. hughesi tachyzoite antigen. This is the first report of S. neurona and N. hughesi exposure in horses in Mexico, and it affirms that EPM should be in the differential diagnosis for horses exhibiting signs of neurologic disease in this country.

Seroprevalence and risk factors of Neospora spp. in donkeys from Southern Italy

In some European countries there is an increasing interest on donkey. Despite there are few data regarding the donkey's parasitic diseases especially those with a protozoal etiology as neosporosis. Samples used in the study were collected from 238 domestic donkeys during year 2010 in Southern Italy from 207 females and 31 males of five breeds (Martina-Franca, Amiata, Sicilian-Grey, Ragusano, Sardinian) and crossbreeds with the average age 9 years (1 month - 24 year). Sera were tested by a competitive-inhibition enzyme-linked immunosorbent assay for antibodies against Neospora caninum; the sera were marked positive, if more than 30% inhibition was found. Out of a total 238 donkeys, 28 (11.8%) were found positive for Neospora antibodies with 12% in females and 6% in males. Different seroprevalence 15.4%, 16%, 12% and 8.8% were found in age categories <1 year, 1-4 years, 5-9 years and ≥10 years, respectively. The seroprevalence ranged in different breeds from 36% (Sicilian-Grey) to 0% (Sardinian) and in different use from 17% (for breeding) to 0% (for meat production). Logistic regression analysis demonstrated evidence of a significant (P<0.05) association between crossbreed origin of samples and risk of protozoan infection; age of donkeys was also significant risk factor for protozoan infection. No statistical significant difference (P>0.05) was found among genders and use of donkeys and risk of N. caninum infection. This is the first serological survey for Neospora spp. performed in donkeys.

Seroprevalence of Toxoplasma gondii in slaughtered horses and donkeys in Liaoning province, northeastern China

Background

Toxoplasma gondii is an important zoonotic pathogen infecting humans and almost all warm-blooded animals. The most common sources of human infection are ingestion of tissue cysts in raw or undercooked meat. However, limited information is available about T. gondii infection in horses and donkeys in China. In the present study, we report the seroprevalence of T. gondii infection in horses and donkeys in Liaoning province, northeastern China.

Methods

Serum samples were collected from 711 and 738 slaughtered horses and donkeys, respectively, in 13 regions of Liaoning province. The modified agglutination test (MAT) was used to test the specific antibodies to T. gondii.

Results

In this study, 178 of 711 (25.0%) horses were seropositive for T. gondii with titers of 1:25 in 81, 1:50 in 62, 1:100 in 33, and 1:200 in 2, and seroprevalence of T. gondii infection from 13 regions ranged from 8.2% to 37.0%. Antibodies to T. gondii were found in 174 of 738 (23.6%) donkeys with titers of 1:25 in 66, 1:50 in 54, 1:100 in 49, and 1:200 in 5, and seroprevalence varied in 13 different regions, ranging from 9.1% to 32.6%.

Conclusions

The results of the present study indicated that the rate of infection with T. gondii in horses and donkeys is a little high in Liaoning province, northeastern China in comparison to other surveys in China, which suggests that consumption of horse and donkey meat in this area may represent a potential source for human infection with T. gondii.

Seroprevalence of Toxoplasma gondii and Neospora caninum infection in dairy cows in subtropical southern China

Toxoplasma gondii and Neospora caninum are closely related protozoan parasites which cause lowered production and increased abortion in dairy cows. The aim of the present study was to determine the seroprevalence of T. gondii and N. caninum infection in dairy cows in the Guangxi Zhuang Autonomous Region (GZAR), subtropical southern China. In total, 875 serum samples were collected from the tail veins of dairy cows in 6 main dairy cow-rearing districts of 4 administrative cities in GZAR. The samples were surveyed for T. gondii antibody using the Indirect Haemagglutination Test (IHA), and 365 of the serum samples were examined for N. caninum antibody by indirect Enzyme-Linked Immunosorbent Assay (ELISA). The overall seroprevalence of T. gondii in dairy cows was 13·71% (120/875), and the average seroprevalence of N. caninum was 15·07% (55/365). There were significant differences in the seroprevalence of N. caninum infection between different districts (P = 0·002, χ2 = 9·261). The highest prevalences of T. gondii and N. caninum were found in cows older than 8 years and those that had completed 5–6 pregnancies. Five cows (1·37%) presented antibodies against both T. gondii and N. caninum, and dairy cows with both T. gondii and N. caninum antibodies had higher abortion rates. The present results indicate widespread exposure of dairy cows to T. gondii and N. caninum in GZAR, subtropical southern China.