Epidemiology in horses involves the study of the distribution and determinants of health-related states and events in equine populations. It encompasses the investigation of patterns, causes, and effects of diseases and health conditions within horse populations. This field of study aims to identify risk factors for disease and targets for preventive healthcare. Key components of equine epidemiology include disease surveillance, outbreak investigation, and the study of disease dynamics within herds or regions. Research in this area often focuses on infectious diseases, zoonotic diseases, and the impact of environmental factors on equine health. This page compiles peer-reviewed research studies and scholarly articles that explore various aspects of epidemiology in horses, including disease prevalence, transmission pathways, and strategies for disease prevention and control.
Solbrig MV.Borna disease (BD), caused by the neurotropic RNA virus, Borna Disease virus, is an affliction ranging from asymptomatic to fatal meningoencephalitis across naturally and experimentally infected warmblooded (mammalian and bird) species. More than 100 years after the first clinical descriptions of Borna disease in horses and studies beginning in the 1980's linking Borna disease virus to human neuropsychiatric diseases, experimentally infected rodents have been used as models for examining behavioral, neuropharmacological, and neurochemical responses to viral challenge at different stages of lif...
Hayama Y, Kobayashi S, Nishida T, Nishiguchi A, Tsutsui T.For determining surveillance programs or infectious disease countermeasures, risk evaluation approaches have been recently undertaken in the field of animal health. In the present study, to help establish efficient and effective surveillance and countermeasures for equine infectious diseases, we evaluated the potential risk of equine infectious disease transmission in non-race horses from the viewpoints of horse movements and health management practices by conducting a survey of non-race horse holdings. From the survey, the non-race horse population was classified into the following five secto...
Viljoen A, Saulez MN, Donnellan CM, Bester L, Gummow B.Medical records of equine after-hours admissions from 1998 to 2007 are reviewed. Data extracted from the medical records included signalment, reason for admission, pre-admission treatment, clinical presentation, procedures performed, final diagnoses, complications occurring in hospital, length of stay and outcome. Eight hundred and twenty after-hours admissions were available of which 75% were classified as emergencies. Most horses originated from Gauteng province (82%), with Thoroughbred, Arabian, and Warmbloods representing 46%, 10% and 7% of horses. Horses had a median age of 7 years and we...
Chevalier V, Dupressoir A, Tran A, Diop OM, Gottland C, Diallo M, Etter E, Ndiaye M, Grosbois V, Dia M, Gaidet N, Sall AA, Soti V, Niang M.In 2005, a serological study was carried out on horses in five ecologically contrasted zones of the Senegal River basin (Senegal) to assess West Nile virus (WNV) transmission and investigate underlying environmental risk factors. In each study zone, horses were randomly selected and blood samples taken. A land-cover map of the five study areas was built using two satellite ETM+ images. Blood samples were screened by ELISA for anti-WNV IgM and IgG and positive samples were confirmed by seroneutralization. Environmental data were analysed using a principal components analysis. The overall IgG se...
Matayoshi M, Kudaka J.Between 1992 and 2007, a total of 86 isolates of Salmonella enterica Weltevreden were obtained from clinical human samples (n = 41), 45 farm animals and their environment on 20 farms, including poultry (n = 25), beef cattle (n = 5), swine (n = 5), dairy cattle (n = 3), mice (n = 2), pony (n = 1), fly (n = 1) and feed samples (n = 3), in Okinawa Prefecture, Japan. Only seven isolates (8.1%) of the isolates were resistance to one or more antimicrobial agents tested; six streptomycin (7.0%), six oxytetracycline (7.0%), two ampicillin (2.3%), two kanamycin, (2.3%), two chloramphenicol (2.3%), two ...
Güiris AD, Rojas HN, Berovides AV, Sosa PJ, Pérez EM, Cruz AE, Chávez HC, Moguel AJ, Jimenez-Coello M, Ortega-Pacheco A.A cross sectional survey was performed to identify gastrointestinal helminths and protozoans in naturally infected horses from the biosphere reserve known as "La Sierra Madre de Chiapas", Mexico (El Triunfo and La Sepultura). During a three-year survey, fecal samples from 90 horses and parasites from 2 necropsied animals were collected. Five families from the Nematoda class: Ascaridae, Kathlanidae, Oxyuridae, Strongylidae and Trichostrongylidae were found, whereas, only one family from the class Cestoda, was observed: Anoplocephalidae. One family from the class Insecta, was observed: Gasteroph...
Sigg L, Gerber V, Gottstein B, Doherr MG, Frey CF.In Switzerland, the prevalence and incidence of equine piroplasma parasite (EPP) infections are unknown. In order to obtain a first insight into the prevalence, a representative sample of 689 sera of horses from Switzerland was serologically tested for the presence of antibodies directed against T. equi and B. caballi using the Indirect Fluorescence Antibody Test (IFAT). A total of 50 (7.3%) horses were seropositive for EPP: overall, the seroprevalence of T. equi was significantly higher than that of B. caballi (p=0.002). The seropositivities in indigenous horses (animals bred and raised in Sw...
Katić I, Bajt VV.Transport of animals by water is a very old way of transport because it is relatively cheap and safe, with a minimum loss of animals. Waterways have been used for the transport of living animals and various goods from ancient times, for example in Ancient Egypt and the Roman Empire. Later, Vikings were so successful in their conquests because they always had trained horses aboard. It is believed that the colonization of America was possible because Spaniards were also bringing many horses with them. Danish possessions in the Caribbean owe much of their economic success in the period between 18...
Ramzan PH, Palmer L.Fissures of the occlusal surface of the equine cheek tooth are poorly understood and their association with dental disease is unknown. Objective: To describe the prevalence and location of occlusal fissures in the cheek teeth (CT) of a group of horses referred for dental investigation/treatment, and determine association with intercurrent dental disease. Methods: Digital video recordings of oral endoscopic examinations for all horses referred to the Rossdales Equine Hospital for dental investigation from November 2006 to June 2009 were reviewed. Location of occlusal fissures in relation to bot...
Wright A, Beard L, Bawa B, Bras J.Equine dysautonomia, also known as equine grass sickness (EGS), is a well documented disease in several countries. To the authors' knowledge, EGS has not been reported previously in North America. This report describes EGS in a 6-year-old female mule in the USA. Failure initially to consider EGS resulted in a delayed diagnosis. EGS should be considered as a differential diagnosis and appropriate diagnostic tests performed in similar cases in North America.
Collins JA, Hanlon A, More SJ, Wall PG, Kennedy J, Duggan V.Significant potential threats to the health and welfare of horses exist in Ireland when supply exceeds demand and the identification system for horses is not yet robust. Objective: To secure engagement with stakeholder groups and determine their perception of equine welfare in Ireland and encourage the development of inclusive, rather than imposed, policy solutions. Methods: A 3 round, web-based Policy Delphi incorporating novel vignette methodology was conducted from November 2007-March 2008 to canvass opinion (in both quantitative and qualitative forms) on the perceived most significant equi...
Quinlivan M, Maxwell G, Lyons P, Arkins S, Cullinane A.Equine rhinitis viruses (ERV) cause respiratory disease and loss of performance in horses. It has been suggested that the economic significance of these viruses may have been underestimated due to insensitive methods of detection. Objective: To develop a sensitive, rapid, real-time RT-PCR (rRT-PCR) assay suitable for the routine diagnosis and epidemiological surveillance of the A and B variants of ERV. Methods: TaqMan primer probe sets for ERAV and ERBV were designed from conserved regions of the 5' UTR of the ERV genome. Over 400 samples from both clinically affected and asymptomatic horses w...
Thorpe CT, Clegg PD, Birch HL.Tendon injury is one of the most common causes of wastage in the performance horse; the majority of tendon injuries occur to the superficial digital flexor tendon (SDFT) whereas few occur to the common digital extensor tendon. This review outlines the epidemiology and aetiology of equine tendon injury, reviews the different functions of the tendons in the equine forelimb and suggests possible reasons for the high rate of failure of the SDFT. An understanding of the mechanisms leading to matrix degeneration and subsequent tendon gross failure is the key to developing appropriate treatment and p...
Lotfollahzadeh S, Mokhber-Dezfouli MR, Tajik P, Bokaie S, Watson DG.The present survey evaluated the use of prohibited substances cases in the first 2 years of medication regulation in horseracing in Iran so that the impact of these regulations on the level of positive cases over the period could be assessed. Objective: To determine the prevalence of positive tests for prohibited substances in horse races during 2 years of a drugs testing programme in Iran. Methods: A total of 656 horses that were winners or second in races were tested during the 2 year study. In the first year 354 horses (209 males and 145 females) and in the second year 302 horses (155 males...
Moura I, Radhouani H, Torres C, Poeta P, Igrejas G.Lusitano horses were investigated in order to detect the presence of vancomycin-resistant enterococci. vanA isolates showed high level vancomycin (Minimum inhibitory concentration; MIC > or = 128 mg/l) and teicoplanin resistance (MIC 64 mg/l), as well as resistance to ciprofloxacin, erythromycin and tetracycline. The tet(L) and erm(B) genes, associated with tetracycline and erythromycin resistance, respectively, were found in all vanA isolates. The intestinal tract of Lusitano horses can be a potential reservoir for vanA-containing enterococci.
Nemoto M, Imagawa H, Tsujimura K, Yamanaka T, Kondo T, Matsumura T.Reverse transcription loop-mediated isothermal amplification (RT-LAMP) was applied to detection of equine rotavirus. Because equine rotavirus of the single P genotype, P[12], is predominant in the equine population worldwide, an RT-LAMP primer set was designed to target the genotype P[12] sequence and thus detect equine rotavirus. The detection limit of the RT-LAMP assay was 10(3) copies of viral RNA, whereas that of semi-nested RT-PCR for genotype P[12] was 10(5) copies. The RT-LAMP assay specifically amplified genotype P[12] but did not amplify the other P genotype strains. The RT-LAMP assay...
Kouam MK, Diakou A, Kanzoura V, Papadopoulos E, Gajadhar AA, Theodoropoulos G.The role of horses in the transmission of parasitic zoonoses either as a source of infection to vectors or through contamination of definitive hosts is gaining importance worldwide. For this reason sera from 773 equids including 753 horses, 13 mules and seven ponies in four regions of Greece were investigated by ELISA for the presence of IgG antibodies against Toxoplasma, Leishmania, Echinococcus and Trichinella. Anti-Toxoplasma antibodies were detected in all regions with an overall prevalence of 1.8%. In contrast, antibodies to Leishmania, Echinococcus, and Trichinella were present only in h...
Rejmanek D, Miller MA, Grigg ME, Crosbie PR, Conrad PA.Sarcocystis neurona is a significant cause of neurological disease in horses and other animals, including the threatened Southern sea otter (Enhydra lutris nereis). Opossums (Didelphis virginiana), the only known definitive hosts for S. neurona in North America, are an introduced species in California. S. neurona DNA isolated from sporocysts and/or infected tissues of 10 opossums, 6 horses, 1 cat, 23 Southern sea otters, and 1 harbor porpoise (Phocoena phocoena) with natural infections was analyzed based on 15 genetic markers, including the first internal transcribed spacer (ITS-1) region; the...
Haridy FM, Shoukry NM, Hassan AA, Morsy TA.Toxoplasma gondii is one of the important zoonotic parasites of worldwide. In this paper the seroprevalence of T. gondii in draught horses (3-15 years) including 90 males and 10 females in the first half of the year 2009 was studied. The result showed that the overall ELISA-T. gondii antibodies were 25% of the horses in Greater Cairo, 50% (females) and 22.2% (males).
Chung TH, Park GB, Lim CY, Park HM, Choi GC, Youn HY, Chae JS, Hwang CY.Identification of the species and strain of dermatophyte can play an effective role in control of disease outbreaks by establishing the source of infection. Current methods of identification are based on cultural and microscopic methods, often involving weeks before a positive identification are made. A rapid molecular diagnostic method would therefore be an important laboratory technique, but requires confirmation in equine clinical practice. Objective: To test the sensitivity and specificity of molecular diagnostic methods applied to a racehorse herd from the Korean Racehorse Authority (KRA)...
Casey MB, Tremaine WH.With the advent of detailed oral examination in horses using dental mirrors and rigid endoscopy, secondary dentinal lesions are observed more frequently. More information regarding the association of secondary dentinal defects with apical dental disease would improve the sensitivity of oral examination as a diagnostic aid for pulpitis. Objective: To assess prevalence and severity of secondary dentinal defects observed on examination of occlusal surfaces of cheek teeth (CT) from horses showing clinical signs of pulpitis compared to asymptomatic controls. Methods: Records from all cases of equin...
Fritzen B, Rohn K, Schnieder T, von Samson-Himmelstjerna G.Increasing prevalence of anthelmintic resistance in equine nematodes calls for a reexamination of current parasite control programmes to identify factors influencing control efficacy and development of resistance. Objective: To investigate if associations occur between prevalence of parasitic nematodes and management practices. Methods: German horse farms (n = 76) were investigated in 2003 and 2004. Information on farm and pasture management with respect to endoparasite control measures obtained using a questionnaire survey. Faecal examinations were performed in parallel. Results: Horses (n = ...
Horváth G, Blahó M, Kriska G, Hegedüs R, Gerics B, Farkas R, Akesson S.White horses frequently suffer from malign skin cancer and visual deficiencies owing to their high sensitivity to the ultraviolet solar radiation. Furthermore, in the wild, white horses suffer a larger predation risk than dark individuals because they can more easily be detected. In spite of their greater vulnerability, white horses have been highly appreciated for centuries owing to their natural rarity. Here, we show that blood-sucking tabanid flies, known to transmit disease agents to mammals, are less attracted to white than dark horses. We also demonstrate that tabanids use reflected pola...
Field H, Schaaf K, Kung N, Simon C, Waltisbuhl D, Hobert H, Moore F, Middleton D, Crook A, Smith G, Daniels P, Glanville R, Lovell D.To determine the epidemiologic and clinical features of a 2008 outbreak of Hendra virus infection in a veterinary clinic in Australia, we investigated the equine case-series. Four of 5 infected horses died, as did 1 of 2 infected staff members. Clinical manifestation in horses was predominantly neurologic. Preclinical transmission appears likely.
Tokateloff N, Manning ST, Weese JS, Campbell J, Rothenburger J, Stephen C, Bastura V, Gow SP, Reid-Smith R.This study estimated the prevalence of methicillin resistant Staphylococcus aureus (MRSA) in nasal swabs of 458 horses in western Canada. The rate of colonization was 1.3% +/- 5.84% [95% confidence interval (CI)], a rate similar to those reported elsewhere. Colonization tended to be transient and seemed unrelated to stress or administration of antimicrobials. Five of the 6 isolates were Canadian epidemic MRSA-5, a human clone that appears to predominate in horses in North America. The other isolate was spa type 539 (t034), a sequence type 398 strain, and this is the first report of this clone ...
Ntafis V, Fragkiadaki E, Xylouri E, Omirou A, Lavazza A, Martella V.Severe outbreaks of diarrhoeic syndrome occurred in young foals at the same stud farm during two consecutive breeding periods namely spring 2006 and 2007. Rotavirus-like particles were detected by electron microscopy in the faeces of the affected foals and group A rotavirus infection was confirmed by Reverse-Transcription (RT)-PCR with selected sets of rotavirus-specific primers. Sequence analysis of the genes encoding the outer capsid rotavirus proteins VP7 and VP4 enabled classification of the viruses as G3AP[12] and revealed that the viruses were highly similar to recently reported equine r...
Martina BE, Koraka P, Osterhaus AD.West Nile virus (WNV) is a neurotropic Flavivirus that was associated with sporadic outbreaks of meningoencephalitis in Africa and the Middle East until 1999, when a more virulent strain emerged in the US that caused thousands of infections among humans and horses, with reported fatality rates between 10 and 50%. Although the epidemiology of WNV is changing into a more endemic pattern in the US, and the incidence of neuroinvasive disease is decreasing, the long-term effects of resolved WNV infections in humans, characterized as persistent movement disorders and various functional disabilities,...
Nemoto M, Matsumura T.This review briefly describes the virus classification, clinical signs, epidemiology, diagnosis, disinfection, and vaccines related equine group A rotavirus (RVA) infection. Equine RVA is one of the most important pathogens causing diarrhoea in foals. The main transmission route is faecal-oral, and the clinical signs are diarrhoea, fever, lethargy, and anorexia (decreased suckling). Some human RVA rapid antigen detection kits based on the principles of the immunochromatographic assay are useful for the diagnosis of equine RVA infection. The kits are used in daily clinical practice because of t...
Karamendin K, Kydyrmanov A, Sayatov M, Strochkov V, Sandybayev N, Sultankulova K.A retrospective phylogenetic characterization of the hemagglutinin, neuraminidase and nucleoprotein genes of equine influenza virus A/equine/Kirgizia/26/1974 (H7N7) which caused an outbreak in Kirgizia (a former Soviet Union republic, now Kyrgyzstan) in 1977 was conducted. It was defined that it was closely related to the strain London/1973 isolated in Europe and it shared a maximum nucleotide sequence identity at 99% with it. This Central Asian equine influenza virus isolate did not have any specific genetic signatures and can be considered as an epizootic strain of 1974 that spread in Europe...
Nyaga PN, Wiggins AD, Priester WA.Three hundred and sixty cases of diagnosed equine influenza reported to the Veterinary
Medical Data Program (VMDP) of the National Cancer Institute, U.S.A., were tested for the
independent effects of age, breed and sex, relative to a reference clinic-hospital population of 84,562
equine patients. Horses of age category 2-6 months showed a significant risk above unity for
infection with equine influenza virus whereas, horses in age category 7-10 yr showed a significant,
low and sparing risk. Horses under two months or over 10 years, as well as those in ages from 6
months to 7 yr had non-s...
Gudmundsdottir KB, Svansson V, Aalbaek B, Gunnarsson E, Sigurdarson S.Twenty isolates of Listeria monocytogenes associated with five confirmed and four suspected incidents of listeriosis in horses in Iceland were characterised by serotyping, pulsed-field gel electrophoresis and ribotyping. Semiquantitative estimates of the numbers of L monocytogenes were made on faeces from horses with clinical signs of listeriosis and on grass silage fed to them. Large numbers of L monocytogenes were often found in the faeces of horses with severe signs of disease. The 20 isolates could be divided into six genotypes, each incident involving only one genotype. One serovar 1/2a g...
Konishi E.The literature on natural infections with Japanese encephalitis virus in Japan and subclinical:clinical infection rates was summarized. To detect natural infections, conventional serologic methods were used in the past, while nonstructural 1 protein-based methods have been used recently. Annual infection rates in humans and horses indicated the status of natural virus activity in Japan.
Crafford JE, Lourens CW, Gardner IA, Maclachlan NJ, Guthrie AJ.African horse sickness is an insect-transmitted, noncontagious disease of equids caused by African horse sickness virus (AHSV). Mortality can exceed 90% in fully susceptible horse populations. A live-attenuated (modified live) cell-culture-adapted (MLV) polyvalent AHSV vaccine is widely used to control African horse sickness in endemic areas in southern Africa. Field studies detailing antibody responses of vaccinated horses are lacking. Objective: To determine antibody titres to the 9 known serotypes of AHSV in a cohort of broodmares that were regularly vaccinated with the MLV AHSV vaccine and...
Chen Y, Cai S, Zhang Y, Lai Z, Zhong L, Sun X, Li S, Lu G.Equine hepacivirus (EqHV) is a newly discovered hepatitis C virus-like virus that can infect equines. EqHV strains circulating worldwide have been classified into subtypes 1-3. In previous studies, we detected the presence of EqHV strains of subtype 1 and 3 in China. To determine whether EqHV strains of subtype 2 are prevalent in China, serum samples were collected from 133 racehorses in Guangdong province in 2021 and were tested for EqHV RNA by RT-PCR, and the positive rate was 9% (12/133). Sequencing of the NS3 gene revealed that one field strain (GD2021) had a high degree of genetic similar...
Weiss R, Böhm KH, Mumme J, Nicklas W.Over a thirteen year period (1965 to 1977) a total of 4790 skin scrapings and hair samples of animals were examined mycologically. 887 strains of dermatophytes were isolated out of 885 of these samples (= 18,5%). Most frequently Trichophyton verrucosum was identified in samples from cattle, followed by Microsporum canis isolated from cats, dogs and zoo animals. T. mentagrophytes was mainly found on guinea pigs, chinchillas and dogs and T. equinum on horses. Although the total number of the samples examined within the last 8 years increased, the total of the dermatophytes isolated remained prop...
Jiménez D, Romero-Zuñiga JJ, Dolz G.Blood samples from 181 equines from the Central Valley of Costa Rica were collected in the year 2012 to determine the presence of antibodies against selected infectious agents in horses and to determine the risk factors associated with these agents. The presence of antibodies against Equine Infectious Anemia Virus (EIAV), Equine Herpes Virus 1 and 4 (EHV-1 and EHV-4), West Nile Virus (WNV), Influenza A Virus (IAV), Equine Viral Arteritis Virus (EVAV), Babesia caballi, Theileria equi, Neospora caninum and Chlamydia abortus was determined using commercial assays, and risk factors associated with...
Laabassi F, Amelot G, Laugier C, Zientara S, Nasri AM, Hans A.In order to determine the prevalence of equine viral arteritis in Algeria, 268 sera from non-vaccinated horses were collected from the western and eastern regions. Serological analysis of the sera, which were collected from 2009 to 2011, was performed using the virus neutralisation test, as described by the World Organisation for Animal Health. Overall, 20 sera (7.46%) were seropositive, 152 (56.71%) were negative and 96 sera (35.82%) were cytotoxic. Equine arteritis virus (EAV) seroprevalence was significantly higher in the western region (Tiaret) than in the eastern region (Barika and El-Eul...
Tantely ML, Guis H, Randriananjantenaina I, Raharinirina MR, Velonirina HJ, Cardinale E, Raveloarijaona N, Cêtre-Sossah C, Garros C, Girod R.In Madagascar, the high West Nile virus (WNV) antibody prevalence reported in horse populations suggests a high level of vector-horse contact. This study aims to characterize the mosquito species usually involved in WNV transmission in horse stables in Madagascar. Five horse stables were investigated in October and November 2016 in five distinct inland areas. Mosquitoes were collected using double net traps baited with human, poultry or horse as well as light traps. Blood meal identification from engorged females was performed using host-specific PCRs. A total of 2898 adult mosquitoes were col...
Al-Obaidi QT, Mohd Mokhtar A, Al-Sultan II, Azlinda AB, Mohd Azam KGK.Equine piroplasmosis (EP) is global disease of equids affect the international movement of horses and their industry. This work was conducted on a random collection of blood samples from a total of 306 equids (horses and ponies) comprising both clinically healthy (n=276) and clinically suspected animals (n=30) for EP from 53 stables in eight districts at Kelantan, Malaysia. Competitive-inhibition enzyme linked immunosorbent test (cELISA) was applied to detect the antibodies for Theileria equi and Babesia caballi and their titers in the serum. Hemato-biochemical parameters were analyzed from bl...
Qiu X, Cao X, Shi N, Zhang H, Zhu X, Gao Y, Mai Z, Jin N, Lu H.Getah virus (GETV) disease is a mosquito-borne infectious disease that causes fever, aseptic meningitis, and abortion in a variety of animals. Currently, the epidemic trend of GETV disease increases seriously worldwide, especially in China, posing a potential threat to animal safety and public health. However, there are few reports about the epidemiological investigation of GETV disease in China as well as a lack of commercial diagnostic kit for GETV antibody. Therefore, the establishment of a rapid, sensitive and suitable GETV antibody detection method for large-scale samples is an urgent req...
Merkt H, Klug E, Bohm KH, Weiss R.A high incidence of Klebsiella contamination in German 'Warmblut' and Thoroughbred stallions is reported. The organism was recovered from the nostrils, prepuce, pre-ejacultory secretion and, in some cases, on the body surface, in the faeces and on the ground of the covering (mating) yard. Fertility was not affected. However, differences of virulence were observed and Type 5 proved to be the most pathogenic.
Costa VMD, Cursino AE, Franco Luiz APM, Braz GF, Cavalcante PH, Souza CA, Simplício KMMG, Drumond BP, Lima MT, Teixeira BM, Kroon EG.Equine infectious anemia (EIA) is listed by the World Organization for Animal Health (OIE) as one of the equine diseases that must be notified. No effective treatment or vaccine is available. EIA control is based on segregation and euthanasia of positive equids. The disease is caused by the equine infectious anemia virus (EIAV), a member of the genus Lentivirus of the Retroviridae family. Despite the importance of this disease in equids, EIA has been poorly studied in donkeys (Equus asinus). We evaluate the sanitary conditions related to EIAV in donkeys from a shelter of abandoned animals capt...