Protozoa are single-celled eukaryotic organisms that can interact with horses in various ways, including as parasites. In equine health, protozoal infections can lead to significant diseases, such as equine protozoal myeloencephalitis (EPM), which is caused by the protozoan Sarcocystis neurona. These organisms can affect the central nervous system and other bodily systems, leading to a range of clinical symptoms in horses. Understanding the life cycle, transmission, and impact of protozoa is important for managing and preventing infections. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, pathogenesis, and diagnostic approaches related to protozoal interactions in horses.
McQueary CA, Worley DE, Catlin JE.Of 22 foals from 4 localities in southwestern Montana, 59% were found to be infected with Eimeria leuckarti. Oocysts collected from feces of 4 positive horses were sporulated and subsequently administered to a 5- to 6-month-old foal. The prepatent period was 31 days and the patent period was between 5 and 10 days.
Lee CG, Ross AD.Klossiella equi in the kidney of a horse is described. Gametocytic and sporogonic stages were observed in the epithelium of the collecting tubules in association with schizonts in the glomeruli and proximal convoluted tubules. The condition was asymptomatic and caused only minor renal damage and inflammation.
Damron GW.A survey of horses for gastrointestinal trichomonads was conducted to determine the organism's role in equine diarrhea and to establish its proper identity and morphology. Trichomonads were found by cultural examination of feces of 101 (35%) of 289 apparently healthy horses. At necropsy, trichomonads were cultured from 11 (37%) of another 30 horses which showed no signs of diarrhea at the time of death. In 4 of the 11 horses, colonies of trichomonads numbered 30,000 to 150,000/ml of cecal fluid. Diarrhea was induced in 1 of 6 horses, with the fecal fluid containing 10,000 to 110,000 trichomona...
Sutoh M, Saheki Y, Ishitani R, Inui S, Narita M, Hamazaki H, Yokota T.This is the first report on Eimeria leuckarti infection in foals in Japan. Seven Thoroughbred or Angloarabian foals 2 to 7 months of age raised in the Hidaka district, Hokkaido, were infected with E. leuckarti. They died of severe alterations caused by the larval migration of Strongylus vulgaris, and were examined over a period from 1970 to 1973. Protozoa of this species were observed in the small intestine in all the foals. They were found mostly in vacuoles of the cytoplasm of monoclear cells in the lamina propria at or near the tip of villi. Various stages of gametocytes, oocysts, and micro...
Erbsloh JK.A short account is given of babesiosis (equine biliary fever) caused by the tick-borne protozoan Babesia equi and B. caballi, endemic in the Cape Province of South Africa. The clinical picture, diagnosis and treatment are described. In the absence of any prophylactic measures, prognosis is poor; control of the parasites in the tick-infested areas is essential.
Vetterling JM, Thompson DE.Kidneys from 5 of 40 ponies (Equus caballus) and from 3 of 14 burrows (Equus asinus) were found infected with Klossiella equi. In addition to previously reported sporogonous stages in epithelial cells of Henle's loop, schizogonic stages in endothelial cells of Bowman's capsule and epithelial cells of the proximal convoluted tubules are described. The association of macro- and micro-gametocytes in syzygy is discounted, and a microgametocyte with 8 to 10 microgametes is characterized. Microgametes in the process of migrating to macro gametes are reported. A life cycle for this parasite is propos...
ADAMS KM.The ciliate population of the large intestine of the horse shows large, daily variations. The ventral colon is the site where the ciliate fauna varies most. Two species, Cycloposthium edentatum and C. dentiferum, became established in the large intestine after passage through the stomach and small intestine. The introduction of new species into the ventral colon caused significant changes in the fauna of that part of the gut.
Balantidium coli is a ciliated protozoan that inhabits the large intestine of swine, man, rodents, and nonhuman primates. Frequently this organism is associated with enteric diseases in man and nonhuman primates, with rare manifestations of disease in swine and other mammalian species. This report describes a case of B. coli-induced enteric disease in a 15-yr-old, mare, Finnish Horse after an acute onset of colic. Severe hemorrhagic and eosinophilic colitis with intense infiltration of intralesional B. coli-like ciliated protozoan were found histologically.
Gürelli G, Canbulat S, Aldayarov N.Species composition and distribution of intestinal ciliates were investigated in the feces from 15 domestic horses living in Bishkek, Kyrgyzstan. Twenty-three species belonging to 14 genera were identified. This is the first study on intestinal ciliates in domestic horses living in Kyrgyzstan. The mean number of ciliates was 14.1 ± 6.8 x10(4) cells ml(-1) of feces and the mean number of ciliate species per host was 6.0 ± 3.2. No endemic or new species were detected. Blepharocorys was the major genus as these ciliates were detected in high proportions. In contrast Holophryoides, Allantosoma w...
MacKay RJ, Howe DK.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 EP...
Vianna AM, Santos AC, Cunha RC, de Souza Stori de Lara AP, Weege GB, Leivas Leite FP.Equine theileriosis is a severe equine disease caused by the protozoan Theileria equi, which is prevalent in tropical and subtropical areas. In this study, a recombinant equi merozoite antigen-2 (rEMA-2) of T. equi was used as an immunogen. Two groups of 10 mice each were divided into control and vaccinated groups. Sixty mares seronegative for theileriosis were divided in two groups, one vaccinated and another group as a control animal. Mice and mares of the vaccinated groups were inoculated with 150 μL of the vaccine containing 50 μg of rEMA-2 and 2 mL of the vaccine containing 200 ...
Kimble KM, Gomez G, Szule JA, Dubey JP, Buchanan B, Porter BF.An adult American Quarter Horse gelding with a history of weight loss presented with an acute onset of colic, fever, soft faeces and elevated liver enzymes. At necropsy, there were gastric mucosal masses and evidence of caecal necrosis. Histologically, the masses were lymph nodes with granulomatous inflammation and areas of liquefactive necrosis. Within and surrounding necrotic areas were free and intrahistiocytic clusters of protozoal tachyzoites. Similar but milder inflammation was evident in the spleen, lungs and liver. Necrotizing typhlitis was also evident. Immunolabelling for Toxoplasma ...
Parra N, Jaume M, Boscán K, Hernández A, Mijares A, González M, Alvarado Y, Restrepo J.Trypanosoma equiperdum is the causative agent of dourine, a venereal disease in horses and donkeys. This parasite has a widely distribution, is found in Africa, Asia, Southern and Eastern Europe, Russia, Mexico and Venezuela. The T. equiperdum is morphologically indistinguishable to other Trypanozoon species, however differs from other mammalian trypanosomes due to the fact that it is primarily a tissue parasite, generating cutaneous plaques, swelling of genitalia and neurological signs. The aim of this study was to evaluate the trypanocidal effectiveness of a set of derivatives of thiosemicar...
Hay AN, Witonsky SG, Lindsay DS, LeRoith T, Zhu J, Kasmark L, Leeth CM. is a ubiquitous parasite in the eastern United States, which is the principal causative agent in the neurologic disorder equine protozoal myeloencephalitis (EPM). While much is known about this protozoa's life cycle in its natural host, the opossum (), little is known of how it acts in the aberrant equine host, which displays a high incidence of exposure with a relatively low rate of morbidity. For this study, we employed the popular interferon gamma knockout mouse model to determine the potential for recrudescence of infection after treatment with the anticoccidial drug diclazuril. Mice wer...
Lauková A, Micenková L, Kubašová I, Bino E, Kandričáková A, Plachá I, Štrkolcová G, Gálik B, Kováčik A, Halo M, Simonová MP.The beneficial influence of bacteriocin-producing, probiotic, mostly non-autochthonous bacteria has already been reported in various animals. However, their use in horses provides limited information, and results with autochthonous bacteria have not been reported. Therefore, the main objective of this model study was to test the effect of autochthonous, bacteriocin-producing faecal strain Enterococcus faecium EF 412 application in horses. One gram of freeze-dried EF 412 strain (10 CFU/mL for 21 days) was applied to horses in a small feed ball. Clinically healthy horses (12), Slovak warm-blood ...
De Carli GA, Tasca T, Pires Borges F.The in vitro hemolytic activity of Tritrichomonas foetus was investigated. The parasite was tested against human erythrocytes of groups A, B, AB, and O, and against erythrocytes of nine adult animals of different species (the rabbit, rat, chicken, cat, dog, swine, horse, bovine, and sheep). The results showed that T. foetus strains (ATCC KV1, K, PAL, 5022, RJ, 90) did not present any hemolytic activity against any human erythrocyte group nor against rabbit, rat, chicken, cat, dog and swine erythrocytes. T. foetus strains, however, lysed horse, bovine, and sheep erythrocytes. No hemolysin relea...
French RA, Meier WA, Zachary JF.Tissues from a 9-year-old American Standardbred gelding with a history of anorexia, mild colic, and unexpected death were submitted to the Laboratories of Veterinary Diagnostic Medicine at the University of Illinois for histopathologic examination. Microscopic diagnoses were severe subacute, diffuse eosinophilic colitis with intralesional protozoa and a subacute to chronic eosinophilic portal hepatitis with granuloma formation. Two tissue-invading, ciliated protozoa were identified in large numbers within the colonic mucosa. The ciliates were Polymorphella ampulla and Cycloposthium sp., Phylum...
Bravo-Ramos JL, Sánchez-Montes S, Sánchez-Otero MG, Ballados-Gonzalez GG, Gamboa-Prieto J, Romero-Salas D, Olivares-Muñoz A.Equine piroplasmosis is a parasitic illness caused by various protozoa of the Babesia and Theileria genera, which parasitize within red blood cells. The transmission of these pathogens occurs through certain genus of ticks, including Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus. In recent times, an increase in the identification of new Theileria species and genotypes has been observed. This is further complicated by the presence of mixed Theileria infections in both mammals and tick vectors, particularly in regions where wildlife and livestock share habitats and vectors. Therefore, th...
Rar V, Marchenko V, Suntsova O, Epikhina T, Tikunov A, Meltsov I, Fedorets V, Igolkina Y, Kozlova I, Tikunova N.Equine piroplasmosis (EP) is a global worldwide infection, which can lead to the death of animals. Despite the causative agents of EP being well studied, there are no data on the distribution and genetic characteristics of EP agents in any region of Russia. In this study, blood samples from 750 horses from Novosibirsk province, Irkutsk province, and Altai region of Russian Siberia were examined for the presence of EP agents. Theileria equi and Babesia caballi were detected in all examined regions, with mean prevalence rates of 60.4% and 7.2%, respectively. The identified pathogens were genetic...
Shams F, Jokar M, Abdous A, Mohammadi P, Abbassioun A, Seuberlich T, Rahmanian V.Neospora spp. and Toxoplasma gondii are two closely related protozoan parasites that are widely distributed throughout the world. Horses can act as intermediate hosts for both parasites and can acquire disease. Blood samples were taken from 487 clinically healthy horses from 17 different mechanized stables in Tehran, the capital of Iran, during September and November of 2022. IFAT and ELISA were employed to detect antibodies directed against Neospora spp. and T. gondii. The anti-N. caninum antibodies were detected in 52 of the horses (10.67%) based on IFAT and in 86 of the 487 horses (17.65%) ...
Lacante SA, Jiang C, Mustamir AA, Mizuno T, Bi X, Syafruddin D, Tokoro M., a human intestinal protozoan parasite of the diplomonad group, has been overlooked because of its commensal features; therefore, molecular studies on this parasite are limited. To address this gap, we designed a molecular screening protocol using polymerase chain reaction (PCR) and DNA sequencing targeting the 18S small subunit ribosomal RNA gene and applied this screening method to the molecular epidemiological analysis of spp. in humans and various livestock. We validated our methodology using stool samples collected from 215 humans and 270 animal hosts (buffaloes, pigs, dogs, goats, hors...
Ungri AM, Dos Santos Sabatke BF, Rossi IV, das Neves GB, Marques J, Ribeiro BG, Borges GK, Moreira RS, Ramírez MI, Miletti LC.Trypanosoma evansi is a unicellular protozoan responsible for causing a disease known as "surra," which is found in different regions of the world and primarily affects horses and camels. Few information is known about virulence factors released from the parasite within the animals. The organism can secrete extracellular vesicles (EVs), which transport a variety of molecules, including proteins. Before being considered exclusively as a means for eliminating unwanted substances, extracellular vesicles (EVs) have emerged as key players in intercellular communication, facilitating interactions be...
Paulino PG, Amaral FB, de Oliveira RT, de Andrade SG, Rabello CA, Meirelles N, de Souza Santana M, Galdino KCP, Jacob JCF, Peckle M, Massard CL....Equine piroplasmosis, a tick-borne disease caused by hemoparasites of the Babesia and Theileria genera, has significant clinical and economic impacts worldwide. This study aims to characterize the heat shock protein 70 kDa (hsp70) gene sequences of Theileria equi from naturally infected horses across the five geographic regions in Brazil, and to analyze the phylogenetic relationships between T. equi and other parasites within the order Piroplasmida. Primers specific to T. equi were designed through in silico analysis of hsp70 gene sequences available in GenBank. Forty samples of equine whole ...
Benitez-Ibalo AP, Debárbora VN, Mangold AJ, Nava S, Sebastian PS.After the previous description and characterization of Theileria equi sensu stricto (Genotype A) in Argentina, the aim of the present study was to investigate the possible heterogeneity of 18 S rDNA genotypes circulating in this country. Therefore, blood samples from 18 horses from two different neighborhoods of Corrientes City, Corrientes Province, were analyzed for infection with Theileria species. Theileria DNA was detected in five samples (27.8%). Four nearly complete 18 S rDNA gene sequences were obtained and phylogenetic analyses were carried out. The maximum likelihood tree constructe...
de Oliveira UV, Varjão JL, de Jesus Deiró AG, Maciel BM, Silva FL, Pinheiro AM, Gondim LFP, Munhoz AD.The aim of this study was to isolate from equids destined for slaughter in a Brazilian slaughterhouse. A total of 354 equids were analyzed, with blood samples collected from all the animals and samples of masseter muscle and brain tissue collected from 319 animals. A serological test was conducted to detect equids with specific antibodies for . Molecular detection of by nested PCR was performed on the tissue samples collected. Tissue samples were tested by murine bioassay in an attempt to isolate either the parasite or the parasite DNA. Real-time PCR was performed on the brain samples from 1...
Talib MT, Nasir A, Kashif M, Rahman A, Rehman AU, Akbar H, Nadeem A, Howe DK, Azam MN.The aim of this study was to determine the prevalence of anti-Neospora (N.) caninum and anti-N. hughesi antibodies in horses and to appraise the associated risk factors in the two central districts (Jhang and Toba Tek Singh) of Punjab Province, Pakistan. A total of 300 horse sera were analyzed for the presence of antibodies to Neospora spp. using a competitive ELISA. The overall prevalence of antibodies against Neospora species in horses was 25 % (75/300; 95 % CI 20.1-29.9). The prevalence of antibodies to N. caninum and N. hughesi species was 12.3 % (37/300; 95 % CI 8.6-16) and 19.3 % (5...
Bhoora RV, Mbaba TV, Troskie M, Ackermann RE, Collins NE.Theileria haneyi is an apicomplexan parasite closely related to Theileria equi, a known causative agent of equine piroplasmosis. The molecular distinction between these parasites relies on a nested polymerase chain reaction (PCR) assay, which has been reported to be unreliable. A recently reported indirect ELISA based on equi merozoite antigen 11 (Thema-11) of T. haneyi can detect geographically diverse T. haneyi strains. Since the ema-11 gene is exclusive to T. haneyi, it was chosen as the target for developing a TaqMan minor groove binder (MGB™) quantitative real-time PCR (qPCR). Published...
Granella MCS, Mendes RP, da Silva Casa M, Ribeiro GSN, Sangioni LA, Vogel FSF, Braünig P, Ferian PE, Salbego FZ, Schwarz DGG, Fonteque JH.Protozoan Neospora spp. is known to negatively affect horses reared in rural and urban environments, being studied for causing abortion, neonatal mortality and central nervous system disorders in horses. This study aimed to verify the occurrence of anti-Neospora spp. antibodies in horses bred in rural and urban areas from southern Brazil and the risk factors associated with infection. The study consisted of 400 horses, which 241 were bred in rural areas and 159 in urban areas. The detection of serum anti-Neospora spp. antibodies was determined using Immunofluorescence Antibody Test (IFAT). The...
Elmahallawy EK, Hassan MF, Cano-Terriza D, Albalawi NO, Fajardo T, Gouda AA, Atiba A, Hendawy A, Villena I, Barakat AM, Alzaylaee H, Almería S....Toxoplasmosis, caused by the intracellular protozoan (), continues to be a widespread parasitic zoonotic disease globally. The seroepidemiology of infection in Egyptian equids, particularly donkeys, remains insufficiently explored. The present study was designed to assess the seroprevalence of in equines from Northern Egypt. Unassigned: A total of 360 serum samples from two equine species (157 horses and 203 donkeys) were obtained during 2023. The Modified Agglutination Test (MAT, cut-off of 1:25) was used to screen for the anti- antibodies. The study also analyzed potential risk factors th...
Firdausy LW, Fikri F, Wicaksono AP, Çalışkan H, Purnama MTE.Trypanosomiasis is a vector-borne parasitic disease with significant implications for animal health and rural livelihoods in Indonesia. Despite surveillance efforts, comprehensive national-level estimates of its prevalence in domesticated animals remain lacking. This study aimed to synthesize the pooled prevalence of trypanosomiasis across Indonesian provinces, identify contributing factors, and assess trends over time using a systematic review and meta-analysis. Unassigned: A systematic search was conducted in seven electronic databases (PubMed, Scopus, Web of Science, ScienceDirect, Cochrane...
Guayaquil G, Chávez C, Enríquez S, Arrivillaga-Henríquez J, Vaca F, Eleizalde MC, Mendoza M, Pedelini L, Martínez-Fresneda M, Uzcanga GL....Trypanosoma evansi, a protozoan parasite of the Trypanozoon subgenus, infects domestic and wild animals, and occasionally humans, worldwide. Despite its significant impact on livestock production, epidemiological studies and molecular analyses of T. evansi based on variant surface glycoproteins (VSG) remain limited in South America. We report the first molecular identification of T. evansi in two localities in the Ecuadorian Amazon and provide phylogenetic and structural analyses of the VSG RoTat 1.2 fragment. Using a retrospective biobank approach, we analyzed DNA from blood samples of dogs a...
