Seroprevalence and risk factors of Neospora spp. and Toxoplasma gondii infections among horses and donkeys in Nigeria, West Africa

Neospora spp. Seroprevalence and Risk Factors for Seropositivity in Apparently Healthy Horses and Pregnant Mares

Simple Summary

Neosporosis, caused by the parasite Neospora species, is recognized as one of the major causes of abortion in cattle worldwide causing large economic losses. Over the past few years, Neospora infection and parasite transmission from the mare to the fetus has been documented in horses and was associated with reproduction failure. In the present study, we investigated parasite prevalence and associated risk factors in the general equine population and in a group of pregnant mares during pregnancy and after parturition. Our findings revealed high exposure of horses to Neospora spp. parasites, with significantly higher prevalence in pregnant mares.

Abstract

Equine Neospora infection has been linked to neurological disorders and infertility in horses. This study looked into the risk factors for infection and the exposure to Neospora spp. in horses. The study was performed in two independent populations in Israel. The first consisted of apparently healthy horses, and the second consisted of mares examined during pregnancy and after parturition. Sera samples collected from horses and mares were tested for Neospora exposure by the indirect fluorescent antibody test (IFAT). The study revealed seroprevalence of 24% in apparently healthy horses and 66.4% and 48.6% in mares during gestation and after parturition, respectively. Among the investigated risk factors, older age (p = 0.026) and housing in both stalls and paddocks (p = 0.033) in apparently healthy horses, and Arabian breeds (p = 0.005) in pregnant mares, were found to be significantly associated with Neospora spp. seropositivity in univariable, but not multivariable, statistical analysis. This study revealed high exposure of equines to Neospora parasites, especially mares. Horse farm management, in combination with active surveillance, including serological testing and follow up, could help reduce the spread of the parasite among horses in endemic areas.

Occurrence of serum antibodies to Toxoplasma gondii and associated risk factors in donkeys from central Kenya

Toxoplasma gondii is an intracellular parasite of zoonotic concern and economic importance in humans and animals, respectively. This study was conducted to determine the occurrence of T. gondii and associated risk factors in domestic donkeys from Kirinyaga and Meru counties in Kenya. Blood samples were collected from 363 randomly selected donkeys for detection of antibodies to T. gondii using a commercial kit ID Screen® Toxoplasmosis Multi-species indirect enzyme-linked immunosorbent assay (ELISA). The data on risk factors were collected by interviewing donkey owners using epidemiological questionnaire. Serum antibodies to T. gondii were detected in 26.4% (95% CI: 22.2-31.3) of the donkeys. The analysis showed that age of donkeys (OR = 2.484, 95% CI: 1.315-4.693; p = 0.005) was associated with increased risk for T. gondii seroprevalence while county of origin of donkeys (OR = 0.182, 95% CI: 0.083-0.400; p = 0.000), residential place of donkeys (OR = 0.301, 95% CI: 0.136-0.665; p = 0.003), rearing chicken (OR = 0.203, 95% CI: 0.064-0.644; p = 0.007), and donkey production system (OR = 0.644, 95% CI: 0.456-0.909; p = 0.012) were associated with reduced risk of T. gondii seroprevalence. This is the first report to provide epidemiological information on T. gondii infection among donkeys in Kenya. The presence of antibodies to T. gondii in donkeys suggests the high potential of transmission to other animals and humans. Regular monitoring and control of T. gondii infection in donkeys were recommended in the study area.

Neospora caninum, a cause of abortion in donkeys (Equus asinus) in Iran

Neospora caninum is an Apicomplexan parasite that can cause enormous economic losses due to abortions in cattle. The present study investigated the role of Neospora spp. infection in equine abortion in Iranian donkeys using molecular and phylogenetic analyses. Twenty-nine-aborted fetuses and 29 blood samples from their dams were collected from six different regions in the West and Northwest of Iran. They were tested for N. caninum by PCR at the Nc5 locus, followed by sequencing of five of the PCR products. The overall molecular prevalence was 34.5% in blood samples and the prevalence by DNA detection in the aborted fetuses was 13.8%. Evidence of transplacental transmission from positive jennies to their fetuses was detected in 40% of aborting jennies. Comparison of the five partial Nc5 sequences (227 bp length) exhibited 98-100% similarity with N. caninum GenBank sequences. This is the first molecular study and genetic characterization of N. caninum in Iranian donkeys suggests that N. caninum may be a significant cause of abortion in donkeys.

Apicomplexan Protozoa Responsible for Reproductive Disorders: Occurrence of DNA in Blood and Milk of Donkeys (Equus asinus) and Minireview of the Related Literature

Donkeys may be susceptible to many pathological agents and may act as carriers of pathogens for other animal species and humans. This study evaluated the occurrence of potentially abortifacient apicomplexan protozoa DNA in blood and milk samples collected at different time periods during lactation (1, 6, and 10 months) from 33 healthy dairy jennies. A total of 73 blood and 73 milk samples were used for DNA extraction and analysis. Blood specimens from 11/33 (33%) jennies scored positive for Theileria equi, while milk samples scored negative. Blood and milk of 3/33 jennies yielded DNA of Toxoplasma gondii at 6 months (n. 1) and 10 months (n. 2) after parturition. Neospora caninum DNA was found in four milk and in five blood samples only at one month after parturition. This study is the first report about the presence of N. caninum DNA in milk of naturally infected jennies. Moreover, the excretion of N. caninum DNA in some of these jennies at 30 days from the parturition may suggest a possible occurrence of an endogenous cycle, while the presence of T. gondii DNA in the milk collected at 6 and 10 months after parturition may be suggestive of a discontinuous excretion.

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.

Toxoplasma gondii infections in birds, companion, food and recreational animals in Nigeria: A systematic review and meta-analysis

Toxoplasma gondii is a protozoan pathogen of zoonotic and economic importance with a global distribution. The pathogen is associated with abortion, stillbirth, neonatal mortalities and mummification in sheep and goats which may also serve as sources of human infections. In pregnant women, the parasite undergoes intrauterine transmission to cause neonatal complications like miscarriage, chorioretinitis, hydrocephalus, cerebral calcification and foetal death. Here, we determine the prevalence and geographical distribution of T. gondii infections in Nigeria using the PRISMA protocol. Prevalence estimates (PE) and heterogeneity were determined by the random-effects model and the Cochran's Q-test respectively. Twenty-eight articles identified, reported 2311 positive cases of Toxoplasma gondii from a total of 9847 animals examined across 15 Nigerian States. Overall PE was 20.70% (95% CI: 15.05-27.78) with a range of 10.18% (95% CI: 2.66-31.98) to 94.00% (95% CI: 89.73-96.56) across sub-groups. PEs varied significantly (p < .05) across host species, with a range of 4.06% (95% CI: 2.47-6.87) to 40.65% (95% CI: 19.88-65.40). PEs in females (22.65%, 95% CI: 15.78-31.72) was significantly higher (p < .05) than that in males (18.97%, 95% CI: 12.78-27.22), while those for adult and young animals were 20.23% (95% CI: 13.42-29.33) and 18.96% (95% CI: 11.11-30.45) respectively. The majority of the studies were published from the south-western region. Toxoplasma gondii infection is prevalent among birds, companion, food and recreational animals from Nigeria. Integrated control strategies including adequate sanitation, cat movement restrictions, public enlightenment are recommended to curtail the menace of T. gondii in animals and its public health consequences in humans.

Age, gender and climate associations with the seroprevalence of Neospora species infection in horses in Jordan

A cross-sectional study was carried out on a sample of 379 horses to determine the seroprevalence of Neospora spp. in Jordan using the indirect fluorescent antibody test. Five variables, namely locality (n=10), climatic zone (n=4), age group (n=3), gender, and breed were tested as risk factors for Neospora-immunoglobulin (Ig)G seropositivity at four cutoff titers (1:50, 1:200, 1:400, and 1:800) using univariate and multivariate logistic regression analyses. A total of 122 (32%; 95% CI: 28, 37) sera samples had anti-Neospora-IgG at a cutoff titer of 1:50. Increased Neospora-IgG seropositivity was found in horses in three localities (Madaba, Zarka, and Petra) and was associated with the following variables: cool temperate climate; age >14 years; and female gender. Seropositivity was found among horses from Madaba at all cutoff titers, Zarka at titers >1:200, and Petra at titers <1:200. Cool temperate climate was associated with titers <1:400. Horses aged >14 years were found to be associated with seropositivity at titers ≥1:200. Female gender was associated with high seropositivity at >1:800.

Serological survey of Neospora spp. and Besnoitia spp. in horses in Portugal

Equine neosporosis is regarded to be caused either by Neospora hughesi or Neospora caninum and equine besnoitiosis is caused by Besnoitia bennetti, both of which are apicomplexan parasites. N. caninum is the only known Neospora species in Europe, where equine N. caninum infections have been reported as being associated to abortion and reproductive failure. N. hughesi is prevalent in North America and was predominantly linked to neurological disorders. B. bennetti is considered an emergent disease in donkeys in North America and evidence for B. bennetti infection was recently reported in Europe. Though N. caninum and Besnoitia besnoiti are prevalent in cattle in Portugal, little is known about neosporosis in horses and, to the best of our knowledge, no information was hitherto available for Besnoitia spp. The aim of this study was thus to carry out a serological survey to determine the seroprevalence of these parasites in naturally exposed horses in Portugal. A total of 385 animals were screened by the Indirect Fluorescent Antibody Test at the cut-off value 1:50 and positive results were confirmed by Western blot. Exposure to Neospora spp. and Besnoitia spp. was confirmed in 9.1% (95% Confidence Interval [CI]: 6.6-12.4%) and 0.3% (95% CI: 0.0-1.5%) of horses, respectively. Considering the putative economic and animal health impact of neosporosis in horses and the consequences of a possible spread of equine besnoitiosis in Europe and elsewhere, more comprehensive studies are needed to characterize the species detected in serological surveys, evaluate the geographical distribution and assess possible risk factors that could favor transmission.

Seroprevalence of Toxoplasma gondii in horses: A global systematic review and meta-analysis

Toxoplasmosis, one of the most common zoonoses worldwide, is caused by Toxoplasma gondii. T. gondii can infect almost all warm-blooded animals, including humans. Horses are an intermediate host of T. gondii, representing a potential risk for humans. To determine the T. gondii seroprevalence in horses worldwide, a global meta-analysis was conducted. A total of 35 publications were obtained by searching the PubMed, ScienceDirect, Chinese Web of knowledge (CNKI) and Wanfang databases. A total of 12,354 horses were assessed, of which 1580 were positive for T. gondii. The pooled overall seroprevalence of horses infected by T. gondii was 11.29%. No significant difference of T. gondii seroprevalence was observed between male and female horses. The seroprevalence of T. gondii in horses from different countries varied. Our findings suggest that toxoplasmosis is prevalent in horses worldwide. Therefore, it is necessary to implement continuous monitoring of the status of T. gondii seroprevalence in horses. Moreover, powerful regulatory measures should be implemented to prevent and control the spread of toxoplasmosis.

Detection of Toxoplasma gondii antibodies in trade donkeys (Equus asinus) at Ganawuri district market, Riyom Local Government area, Plateau State, North Central Nigeria

Background and Aim: Toxoplasma gondii is a parasite of public health significance due to its possible transmission to humans through ingestion of tissue cysts in raw or undercooked meat or food or water contaminated with oocysts shed by felids and transplacental transmission. This study was carried out to provide information on the possible risk of transmission through eating undercooked donkey meat by conducting a market based cross-sectional study design to determine the presence of T. gondii antibodies in trade donkeys in Ganawuri district, Riyom Local Government Area, Plateau State, North Central, Nigeria. Materials and Methods: One hundred and thirteen serum samples were collected from trade donkeys at the market and analyzed for T. gondii antibodies using latex agglutination test (LAT). Serum samples with LAT titer >10 μl/ml were considered positive. Results: The distribution of the donkeys based on their sources showed that greater proportions (61.1%) were from North Eastern part of the country. The study showed that 31 of the serum samples collected and analyzed were positive for T. gondii antibodies given an overall prevalence of 27.4%. The prevalence ranges between 22.2 and 33.3% across the states where the donkeys were sourced. The study showed that seropositivity increases with age (p=0.003; OR=11.8) and ranges between 12.5 and 47.2%. The prevalence did not vary significantly based on sex and source/location (p=0.494, OR=0.05; 0.920, 1.45, respectively). Conclusion: This study showed that trade donkeys at Ganawuri district market have antibodies to T. gondii and suggest a public health risk from the consumption of undercooked donkey meat.

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 of Toxoplasma gondii infection and variables associated with seropositivity in donkeys in eastern China

Donkeys (Equus asinus) are widely distributed throughout China; they are used for their meat, as food, and certain donkey-derived items are also important for traditional Chinese medicinal purposes. However, only limited information is available on Toxoplasma gondii infection in donkeys in China, especially the eastern region, which is one of the largest production areas. Thus, the present study was conducted to detect specific anti-T. gondii antibodies using a commercially available indirect hemagglutination test (IHA) kit and to evaluate the risk factors that are associated with seroprevalence in the Shandong province of eastern China. A total of 213/1278 (17%) donkeys tested from Shandong province were positive for T. gondii antibodies. Statistical analysis revealed that gender and feeding habits of the animal are associated with T. gondii infection. These results provide information for the prevention and control of toxoplasmosis in donkeys, other animals, and humans in this region and elsewhere.

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.

Prevalence of Neospora spp. in donkeys in China

This study was conducted to detect specific anti-Neospora antibodies using a commercial competitive-inhibition ELISA kit, and to evaluate the risk factors for Neospora spp. infection. Out of a total of 2,228 donkey sera collected in three provinces in China, 211 (9.5%) were found to be positive for anti-Neospora antibodies. Statistical analysis revealed that age (p = 0.019, OR = 1.62, 95%CI: 1.08-2.44), feeding status (p < 0.001, OR = 3.79, 95%CI: 2.65-5.43), miscarriage history (p = 0.006, OR = 2.56, 95%CI: 1.27-4.01), and contact with dogs (p < 0.001, OR = 2.69, 95%CI: 1.86-3.88) were significant risk factors for Neospora spp. infection. This is the first evidence of Neospora infection in donkeys in China.