Prevalence of anti-Toxoplasma gondii antibodies in sport horses from Qazvin, Iran

Evidence of intrathecally-derived antibodies against Toxoplasma gondii in horses suspected of neurological disease consistent with equine protozoal myeloencephalitis

Among the recognized neurologic diseases in horses, equine protozoal myeloencephalitis (EPM) has been reported around the world and still presents challenges in diagnosis and treatment. Horses can present with clinical neurologic signs consistent with EPM while testing negative for the two main causative agents, Sarcocystis neurona or Neospora hughesi, and may still be clinically responsive to anti-parasitic drug therapy. This context led to our hypothesis that another protozoal parasite, Toxoplasma gondii, which is known to cause toxoplasmosis in other mammalian species, is a potential pathogen to cause neurologic disease in horses. To evaluate this hypothesis, serum and cerebrospinal fluid (CSF) were collected from 210 horses presenting with clinical signs compatible with EPM, and the indirect immunofluorescent antibody test (IFAT) was used to detect antibody titers for T. gondii, S. neurona, and N. hughesi. Additionally, the serum to CSF titer ratio was calculated for T. gondii, S. neurona, and N. hughesi infections, suggesting intrathecally-derived antibodies for each of the three agents if the serum:CSF ratio was ≤ 64. There were 133 (63.3%) horses positive for serum T. gondii antibodies using a cutoff titer of 160, and 31 (14.8%) positive for CSF T. gondii antibodies using a cutoff titer of 5. Overall, 21 (10.0%) of EPM-suspect horses had a serum:CSF ratio ≤ 64 for antibodies for T. gondii, while 43 (20.5%) and 8 (3.8%) horses had a serum to CSF ratio ≤ 64 for antibodies for S. neurona and N. hughesi, respectively. A total of 6 (2.9%) animals presented evidence of concurrent intrathecally-derived antibodies for T. gondii and at least one other apicomplexan parasite in this study. Signalment and clinical signs were not different across the groups aforementioned. These data provide evidence of intrathecal production of anti-T. gondii antibodies, indicative of T. gondii infection in the brain and/or spinal cord of horses with EPM-like disease.

Prevalence of endo- and ecto-parasites of equines in Iran: A systematic review

Equines are subject to infection with many parasites, which threaten their health. In the present study, we systematically reviewed existing literature on the prevalence of endo- and ectoparasites of equines in Iran. Major electronic databases, including PubMed, PubMed Central, Google Scholar, Science Direct and Scientific Information Database (SID), were searched (Last updated 11/05/2018) for relevant literature of parasites that have been identified from equines in Iran. Of the 1809 titles produced by bibliographic search, 38 were included in the review. Twenty-seven of the studies were on horses, six on donkeys, three on both horses and donkeys, and one study was on both horses and mules. Furthermore, 24 of the studies reported infections caused by protozoa, thirteen by helminths, two by ectoparasites, and one by both protozoa and helminths. The overall pooled prevalence of parasitic infection was 28.8% (95%CI: 22.9-35.7, I2  = 93.4%). Helminths were the most prevalent parasites 46.7% (95% CI: 24.1-70.7, I2  = 96.0%). Furthermore, donkeys were the most affected equine, with a prevalence of 70.7% (95% CI: 53.2-83.7, I2  = 92.5%). The protozoa frequently reported included nine species belonging to the genera: Neospora, Toxoplasma, Theileria, Babesia and Eimeria. Also, the helminths frequently reported included 21 species belonging to the genera: Strongylus, Dicrocoelium, Oxyuris, Habronema, Echinococcus, Dictyocaulus, Cyathostomum, Probstmayria, Anoplocephala, Setaria and Fasciola. Ticks were the only ectoparasites frequently reported. Parasitic fly species of the genera Gasterophilus were also reported. The study-level risk of bias was likely to be high because of differences in study design. Parasitic infections of equines in Iran are frequent and caused by a diversity of parasites, which threatens the health and well-being of these animals. Further research is needed in the area to identify the risk factors of infection for effective control of the parasites.

Parasitic diseases of equids in Iran (1931-2020): a literature review

Parasitic infections can cause many respiratory, digestive and other diseases and contribute to some performance conditions in equids. However, knowledge on the biodiversity of parasites of equids in Iran is still limited. The present review covers all the information about parasitic diseases of horses, donkeys, mules and wild asses in Iran published as articles in Iranian and international journals, dissertations and congress papers from 1931 to July 2020. Parasites so far described in Iranian equids include species of 9 genera of the Protozoa (Trypanosoma, Giardia, Eimeria, Klossiella, Cryptosporidium, Toxoplasma, Neospora, Theileria and Babesia), 50 helminth species from the digestive system (i.e., 2 trematodes, 3 cestodes and 37 nematodes) and from other organs (i.e., Schistosoma turkestanica, Echinococcus granulosus, Dictyocaulus arnfieldi, Parafilaria multipapillosa, Setaria equina and 3 Onchocerca spp.). Furthermore, 16 species of hard ticks, 3 mite species causing mange, 2 lice species, and larvae of 4 Gastrophilus species and Hippobosca equina have been reported from equids in Iran. Archeoparasitological findings in coprolites of equids include Fasciola hepatica, Oxyuris equi, Anoplocephala spp. and intestinal strongyles. Parasitic diseases are important issues in terms of animal welfare, economics and public health; however, parasites and parasitic diseases of equines have not received adequate attention compared with ruminants and camels in Iran. The present review highlights the knowledge gaps related to equines about the presence, species, genotypes and subtypes of Neospora hughesi, Sarcocystis spp., Trichinella spp., Cryptosporidium spp., Giardia duodenalis, Blastocystis and microsporidia. Identification of ticks vectoring pathogenic parasites, bacteria and viruses has received little attention, too. The efficacy of common horse wormers also needs to be evaluated systematically.

High Exposure to Toxoplasma gondii and Neospora Spp. in Donkeys in Israel: Serological Survey and Case Reports

Simple Summary

Toxoplasma gondii and Neospora spp. are major pathogenic parasites of animals worldwide, with the first also affecting humans. These parasites have two-host life cycles, with the cat and the dog being the definitive hosts of T. gondii and N. caninum, respectively. Both parasites can infect various animal species, as intermediate hosts, in which they form tissue cysts and may cause abortions and neurological disease. Both parasites have been reported in wild and domestic animals in Israel. This study aimed to evaluate the serologic exposure of donkeys to these parasites. A total of 98 donkeys were examined. Half of them (n = 49) were from animal shelters in Israel, and the rest (n = 49) were working donkeys from the Palestinian Authority. Anti-T. gondii antibodies and anti-Neospora spp. antibodies were found in 94% and in 70% of the donkeys, respectively. In addition, two cases of donkeys presenting N. caninum tissue cysts, which were detected during post-mortem examination, were described. This is the first report of the exposure of donkeys to Toxoplasma gondii and Neospora spp. in the area. The exposure of donkeys to both parasites was considerably higher than the exposure of other species in the area and may be the result of poor husbandry conditions and higher exposure to infection. These results indicate that donkeys may have an important role in the maintenance and transmission of these parasites.

Abstract

Toxoplasma gondii and Neospora spp. are closely related cyst-forming coccidian parasites, which infect various animal species and have considerable zoonotic and economic implications, respectively. Both parasites are endemic in Israel and have been reported to infect wild and domestic animals. This study was conceived to evaluate the serologic exposure of donkeys to these parasites. Serum samples were collected from 98 donkeys. Half of them (n = 49) were from animal shelters in Israel, and the rest (n = 49) were working donkeys from the Palestinian Authority. The donkeys were screened for the presence of anti-Toxoplasma and anti-Neospora antibodies by immunofluorescence antibody tests (IFATs). The seroprevalence of T. gondii and Neospora spp. was 94% and 70%, respectively, and 69% of the donkeys were exposed to both parasites. In addition, N. caninum tissue cysts were documented in two donkeys during post-mortem examination. This is the first report of the exposure of donkeys to T. gondii and Neospora spp. in the area. The high prevalence found in this study suggests that donkeys may have a role in the maintenance of these parasites in the area, thus serving as a source of infection for the definitive hosts.

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.

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.

Factors associated with the distribution of natural Toxoplasma gondii infection among equids in Northeastern Brazil

The aim of this study was to determine the frequency and factors associated with Toxoplasma gondii in naturally infected equids in northeastern Brazil. Serum samples from 569 equids (528 horses, 8 mules and 33 donkeys) were subjected to the indirect fluorescent antibody test. Generalized linear models were used to evaluate associated factors. Among the 569 animals sampled, 118 (30.6%) living in rural areas and 14 (26.42%) in urban areas were seropositive (p>0.05). Seropositive animals were observed on 95% of the farms and in all the municipalities. Donkeys/mules as the host, presence of domestic cats and rats on the farm, ingestion of lagoon water and goat rearing remained in the final model as factors associated with infection. Preventive measures such as avoiding the presence of domestic cats close to rearing areas, pastures and sources of water for the animals should be adopted. The wide-ranging distribution of positive animals also indicated that infection in other domestic animals and in humans, through the contaminated environment, was possible. It should be highlighted that there was the possibility that donkeys and mules would continue to have detectable titers for longer, thus explaining the prevalence found. Further studies are needed to confirm this possibility.

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.

Prevalence of anti-Toxoplasma gondii antibody in domestic horses in Japan

The present study is the first report that investigated the seroprevalence of Toxoplasma gondii infection in domestic horses in various prefectures of Japan and analyzed risk factors for seropositivity. We performed a latex agglutination test for riding/racing horses from 11 prefectures in Japan (783 samples) and 4 groups of Japanese native horses (254 samples). The total seroprevalence of anti-T. gondii antibody in horses examined in this study was 4.24% (44/1037). As for riding/racing horses, we did not find a statistically different T. gondii seroprevalence between sampling prefectures. In contrast, seroprevalence of T. gondii in older horses (>21 years) was significantly higher than that in younger horses (<5 years and 11-15 years). There was no significant difference in T. gondii seroprevalence between riding/racing horses and Japanese native horses. Logistical regression analysis revealed that age, but not sex and usage, is a significant risk factor of T. gondii infection for domestic horses in Japan. These findings suggest that domesticated horses in Japan can be horizontally infected with T. gondii by ingestion of food or water contaminated with oocysts.

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.

Seroprevalence of Toxoplasma gondii and Neospora spp. Infections in Arab Horses, Southwest of Iran

BACKGROUND

Because of the economic importance of the Arab race horses and also the role of Toxoplasma gondii and Neospora spp. in abortion and reproductive failure of these animals, we decided to perform this study.

OBJECTIVES

We designed this study to investigate the seroprevalence of anti-Toxoplasma gondii and anti-Neospora spp. antibodies in Arab horses from 12 cities of Khuzestan province in southwest of Iran.

MATERIALS AND METHODS

From October 2009 to March 2011, a total of 235 blood samples were collected from jugular veins of Arab horses of different ages and genders from 12 cities of Khuzestan province. All the sera were tested for anti-Toxoplasma antibodies using the modified agglutination test (MAT) and the existence of anti-Neospora antibodies were tested using N-MAT for Neospora spp.

RESULTS

According to the MAT results, antibodies to T. gondii were found in 114 (48.5%) of 235 sera with titers of 1:20 in 84, 1:40 in 19, 1:80 in four, 1:160 in four, and 1:320 in three horses. According to the N-MAT results, antibodies to Neospora spp. were found in 47 (20%) of 235 sera with titers of 1:40 in 39, 1:80 in five, and 1:160 in three horses. We did not observe any statistically significant differences regarding age groups and genders between seropositive and seronegative horses for Neospora spp. using chi-square (χ(2)) test, but it seemed that anti-Toxoplasma antibodies were more prevalent in older horses (≥ 10 years old).

CONCLUSIONS

The results indicated that Arab horses are exposed to these parasites in southwest of Iran. Further research is required to determine the genomic structures of these parasites in Arab horses in southwest of Iran.

Serological study of Toxoplasma gondii infection in Turkoman horses in the North Khorasan Province, Iran

Toxoplasmosis is an important zoonotic disease with worldwide distribution. The infection is observed in an unusually wide range of warm-blooded animals, including most of the livestock and humans. Many studies have shown high prevalence of toxoplasmosis in man and animals in Iran. The present study was conducted to investigate the seroprevalence of toxoplasmosis in Turkoman horses in the North Khorasan Province. During 2011-2012, 100 blood samples from horses were collected and tested for antibodies against toxoplasmosis using indirect fluorescent antibody test. The seroprevalence of toxoplasmosis was detected in 14 % (14) horses. The antibodies titres were detected in the range of 1:20-1:160 dilution. The lowest and highest frequencies of toxoplasmosis were observed in the age groups of <1 year and 1-10 years, respectively (P < 0.05). No significant difference was observed between toxoplasmosis frequencies and gender and usage of horses. With regard to the high frequency of toxoplasmosis in the sampled horses, attention must be paid to the animal health for the control and prophylaxis of the disease.

Molecular and Serological Evaluation of Toxoplasma gondii Infection in Reared Turkeys in Fars Province, Iran

Background:

Toxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii. This parasite infects most of warm-blooded animals, including birds. Turkeys are one of these animals which might be infected by this parasite. Little is known about the prevalence of T. gondii in turkeys in Iran.

Objectives:

The current study aimed to evaluate the rate of Toxoplasma infection in turkeys in Fars Province, Southern Iran.

Materials and Methods:

Sera and tissues (brain, neck and tongue) of 54 turkeys were collected from Shiraz slaughterhouse in Fars province. Anti-Toxoplasma antibodies were assessed in the collected sera using modified agglutination test (MAT), while tissues were evaluated by polymerase chain reaction (PCR) and bioassay methods.

Results:

T. gondii antibodies (MAT titer: ≥ 1:40) were found in 89.8% of turkeys. T. gondii DNA was detected in 61.6% of turkey tissues and brain had the highest rate of infection. Brain tissues from each animal were bioassayed and Toxoplasma tissue cysts were found in 11.5% and Toxoplasma DNA in 62% of inoculated mice.

Conclusions:

Results of this study validated a relatively high level of Toxoplasma infection in reared turkeys and turkey meat might be considered as an infection sources for human.

Seroprevalence of Toxoplasma gondii in horses and donkeys in Yunnan Province, Southwestern China

Background

Toxoplasma gondii is an intracellular protozoan parasite that infects almost all warm-blooded animals, including humans, with a worldwide distribution. There have been limited reports about the seroprevalence of T. gondii infection in equids around the world and little is known about the seroprevalence of T. gondii in equids in southwestern China, in particular in Yunnan Province. The objective of the present investigation was to estimate the seroprevalence of T. gondii infection in equids in this area.

Methods

A total of 399 serum samples (266 from horses and 133 from donkeys) were collected in 2012, and assayed for T. gondii antibodies by Indirect Haemagglutination (IHA) test using a commercially available kit.

Results

A total of 108 (27.1%) equids, including 81 (30.5%) horses and 27 (20.3%) donkeys were positive for T. gondii antibodies, and the seroprevalence ranged from 18.8% to 37.5% among different sampling areas. The seroprevalence was 27.4% and 26.8% for male and female equids, respectively, and the difference was not statistically significant (P > 0.05). The seroprevalence ranged from 21% to 32.9% among different age groups, and the difference was not statistically significant (P > 0.05).

Conclusions

The results of the present survey indicated the existence of high T. gondii seroprevalence in Yunnan Province, southwestern China, which has significant public health concern. Therefore, it is imperative that improved integrated measures be carried out to prevent and control T. gondii infection in equids in the studied region.