Disease transmission in horses refers to the spread of infectious agents such as bacteria, viruses, fungi, and parasites among equine populations. These pathogens can be transmitted through various routes, including direct contact, vector-borne transmission, or environmental exposure. Factors influencing disease transmission include horse density, management practices, and biosecurity measures. Understanding the mechanisms and conditions that facilitate the spread of diseases is essential for developing effective prevention and control strategies. This page compiles peer-reviewed research studies and scholarly articles that investigate the modes of transmission, risk factors, and management practices related to infectious diseases in horses.
Gibbs EP.The most important neurotropic viral infections of the horse are the arthropod-borne encephalitides. These include Venezuelan encephalitis (VE), eastern encephalitis (EE) and western encephalitis (WE), which are found in the Americas, and Japanese B encephalitis which occurs in the Far East. All the viruses cause encephalitis in man. Between 1969 and 1972 an epidemic of VE occurred in Central America. In 1971 the disease was reported in Texas, where it was brought under control by the vaccination of susceptible horses with an attenuated live virus vaccine and by the reduction of the mosquito p...
Morse EV, Duncan MA, Page EA, Fessler JF.Salmonellosis in Equidae is a serious global problem. The prevalence may range from 0.36% to 27%. Probably 5% to 10% of the equine population in the U.S. is or has been infected. Over 40 serotypes of Salmonella have been cultured from Equidae. S. typhimurium (66.31%), S. enteritidis (9.6%), S. newport (5.16%) and S. heidelberg (4.89%) have been the most common equine isolates. The clinical and bacteriological studies of 23 naturally occurring infections in a large veterinary hospital were studied. Nine patients were infected with S. typhimurium, 8 with S. anatum, 1 with S. newport, 4 with dual...
Ordonez JV, Scherer WF, Dickerman RW.During the wet seasons of 1972 and possibly 1971, sentinel horses became infected by Venezuelan encephalitis (VE) virus in a temporally and geographically progressive manner inland from an enzootic marsh focus of virus on the Pacific couast of southeastern Guatemala. During the wet seasons of 1972 and 1973, VE virus was detected by sentinel horses (and a sentinel hamster in 1972) in a small woods 10 km north of the marsh, but virus was undetectable there during the dry seasons of 1973 and 1974 and the wet season of 1974. Culex (Melanoconion) mosquitoes were found in this woods and at the marsh...
Hawkins JA, Adams WV, Wilson BH, Issel CJ, Roth EE.The mechanical transmission of equine infectious anemia (EIA) virus by Tabanus fuscicostatus was investigated. In 1 of 7 transmission trials, a single horsefly transmitted EIA virus from an acutely infected pony to a susceptible pony. Groups of horseflies isolated for 3, 10, or 30 minutes before refeeding transmitted EIA virus, whereas those isolated for 4 or 24 hours did not. Data from field studies indicate that the home range or flight distance of horseflies may exceed 4 miles. That information together with our observations suggest that segregation of infected horses (usually defined as at...
Genchi C, Malnati G.Strongyloides westeri larvae transmission by mare milk in foals has been studied; the results show the importance of this route for parasite penetration.
Boudreault A, Boulay G, Marois P, Pavilanis V.Live human and equine influenza virus strains modified by serial passage on allantois-on-shell system (AOS) in the presence of normal horse serum were administered orally or intranasally to volunteers or horses. Mostly mild clinical short-lasting reactions, replication in nasal mucosae, transmission to placebo recipients and significant local or circulating antibody rises were observed following administration to volunteers of strains modified by five or less serial passages on AOS in the presence of normal horse serum (NHS). Milder clinical reactions, no replication, no viral transmission and...
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.
Pascoe RR, Bagust TJ.Equine coital exanthema can be produced experimentally in stallions by inoculation with an equine herpesvirus (strain 65/61) and be transmitted during coitus with an infected mare. Serological responses to this infection include the production of complement-fixing and serum-neutralizing antibodies which reach maximum levels 14 to 21 days after infection. Complement-fixing antibodies decline rapidly and are usually not detectable by 60 days after infection, whereas serum-neutralizing antibody activity is maintained for at least 1 year. This disparity provides a useful method for the diagnosis o...
Lewis GE, Huxsoll DL, Ristic M, Johnson AJ.Dogs (German Shepherd Dogs and Beagles), cates, rhesus macaques (Macaca mulatta), and baboons (Papio anubis) were inoculated with Whrlichia equi, the etiologic agent of equine ehrlichiosis. Within 3 to 7 days after inoculation, morulae were observed in the eosinophils of cats, neurtrophils of macaques and baboons, and in both neutrophils and eosinophils of dogs. The severe disease produced in horses by this agent was not a feature of E equi infection in dogs, cats, macaques, and baboons. However, a susceptible horse, inoculated with the pooled blood of 2 infected macaques, developed severe cli...
McGuire TC, Poppie MJ, Banks KL.Measurement of serum immunoglobulins in 46 foals less than 2 weeks old revealed 9 foals with hypogammaglobulinemia. The hypogammaglobulinemia was attributed to failure in transfer of immunoglobulins from dam to foal via colostrum. Three of the affected foals did not nurse at all, or only slightly, and 2 of these died of infections within a few days after birth, whereas the 3rd foal did not grow as well as normal foals. Six of the affected foals nursed in an apparently normal manner, and 5 of these had nonfatal respiratory infections between 2 and 5 weeks of age. Analysis of serum samples from ...
Whitlock F, Grewar J, Newton R.The epidemiology of equine influenza (EI) in the United Kingdom has not been systematically described since the 2019 epidemic. Objective: To summarise UK EI surveillance (2020-2024), quantify outbreak seasonality and assess movement-related sources. Methods: Retrospective observational analysis of national surveillance and horse importation data. Methods: Epidemiological data for laboratory-confirmed EI cases in the United Kingdom were collated. Outbreaks (EI-infected premises) were defined as one or more laboratory-confirmed cases on the same premises within a 4-week period. Monthly outbreak ...
Kydd J, Nielsen M, Waller A.Julia Kydd, Martin Nielsen and Andrew Waller highlight some of the key presentations given at last year's 11th International Equine Infectious Diseases Conference, which was held virtually.
Malek IA, Baharudin F, Peng TL, Sabri J.Equine strongyles are harmful gastrointestinal parasites affecting horses' health and productivity. In tropical regions, environmental conditions, including temperature and soil type, significantly influence the development and survivability of strongyle larvae. This study aims to assess the development and survival of third-stage larvae (L3) of strongyles under different temperatures and soil types commonly found in Malaysia. Faecal samples from five adult horses aged between 22-24 years that were kept under a semi-intensive management system and had no history of recent anthelmintic treatmen...
Germann JA, O'Sullivan TL, Greer AL, Spence KL.This study aimed to describe implementation of biosecurity practices by Ontario horse owners and investigate whether biosecurity implementation was associated with horse-owner demographic characteristics and personality traits. Unassigned: A cross-sectional questionnaire was administered to a convenience sample of horse owners in Ontario to collect data on demographics, personality traits, risk comprehension, and biosecurity practices. Hierarchical cluster analysis was used to identify clusters of participants with shared personality traits, and univariable associations between clusters and de...
Soni S, Eertink LG, Shuisong N, Loynachan A, Barnum SM, Adam EN, Kennedy MA, Wang D, Li F.Rotaviral diarrhea in foals is caused by two dominant G3P[12] and G14P[12] genotypes of equine rotavirus A (ERVA). Protection of foals against ERVA infection and disease is achievable by passive antibody transfer through colostrum from mares receiving inactivated monovalent G3P[12] vaccine. Simian rotavirus SA11 G3P[2] is also included in ERVA vaccines to protect foals. Here, we characterized cross-neutralization and protection among three distinctive rotaviruses carrying the same or different G (defined by VP7) or P (defined by VP4) genotype by using a rabbit and equine monospecific antisera ...
Romaniuk K.The Diptera attacked domestic animals in Poland are: Simuliidae, Culicidae, Tabanidae, Gasterophilidae, Hypoder-matidae and Muscidae. The insect assail the crazing animals, mostly during sunny day dna at close of day. Lack of effective repelents and also difficulties with their usage, makes it impossible to complete extermination of parasitic insects in the environment. It is posible to effectively fight against Hypoderma bovis and Gasterophilus spp.
Hale D.West Nile Virus is the most frequent cause of arboviral disease in the United States. It was first identified in the United States in 1999. Since that time, each of the 48 contiguous states in the United States has seen the disease, and it has been found in 96% of the U.S. counties in infected humans, mosquitoes, birds, horses, or other mammals. Although most often the disease resolves on its own, patients can develop serious and life-threatening complications, and may need further monitoring and treatment. This article reviews the prevalence, transmission, signs and symptoms, complications, t...
Dieleman EF.This review describes research conducted from 1900-1983 on trypanosomiasis due to Trypanosoma evansi in Indonesia. Clinical signs and post-mortem findings in horses, cattle, buffaloes, pigs and dogs, experimental transmission tests to establish possible surra vectors in Indonesia, and research on chemotherapy and chemoprophylaxis are discussed.
Britton AL, Major DA, Perry GH, Read AJ.The interaction and stabling of horses at equine events may have a substantial impact on the spread of a zoonotic disease. This study aimed to investigate the spread of equine influenza (EI) at an equestrian event at the start of the Australian outbreak. Around one-third of the competing horses were stabled overnight at the event and, of these, 70% developed symptoms of EI within 7 days. The index case was never positively identified, but stabling position and disease onset provided clues to its potential identity.
García Sánchez A, Zurita SG, Gil Molino M, Martin Cano FE, Barraso Gil C, Hermoso de Mendoza Salcedo J.The aim of this study is to describe an outbreak of dermatophilosis at an equestrian center in Castilla la Mancha (central Spain), which affected 16.6% (5/30) of the animals. Research was carried out to establish the mode of transmission and spread to other horses in the herd. Clinical features, diagnostic methods and treatment are also described. O objetivo deste estudo é descrever um surto de dermatofilose em um centro equestre em Castilla la Mancha (centro da Espanha), no qual 16,6% (5/30) dos animais foram afetados. Foi realizada uma pesquisa para estabelecer o modo de transmissão e a di...
Hain-Saunders N, Knight DR, Bruce M, Riley TV.Recent increases in community-associated Clostridioides difficile infections have highlighted the importance of monitoring toxigenic C. difficile from animal and environmental sources. We provide the complete circularized genomes of two toxigenic C. difficile strains isolated from feral horse faeces. Genome N64 (sequence type 964) consists of a single chromosome of 4,078,791 bp, while genome H251 (sequence type 963) comprises one chromosome (4,304,722 bp) and three plasmids (150,942 bp, 11,534 bp, and 9,074 bp).
Hara Y, Nakajima T, Akamatsu M, Yahiro M, Kagawa S, Petry S, Matsuda M, Moore JE.Contagious equine metritis is a bacterial infectious disease of horses caused by Taylorella equigenitalis, a Gram-negative eubacterium. The disease has been described in several continents, including Europe, North America and Asia. A novel molecular method was developed to detect clustered regularly interspaced short palindromic repeats (CRISPRs), which were separated by non-repetitive unique spacer regions (NRUSRs) of similar length, in the Taylorella equigenitalis EQ59 strain using a primer pair, f-/r-TeCRISPR-ladder, by PCR amplification. In total, 31 Taylorella isolates (17 T. equigenitali...
Hosseinzadeh S, Nofouzi K, Hasanzadeh F, Esmaeili S, Ayen E.Q fever is a frequently occurring illness that is induced by the bacterium ) that can infect humans and various animals. It targets the macrophage cells in the tissues, and circulating monocytes. Unassigned: This study was conducted between 2022 and 2023 in the West Azerbaijan and Ardabil provinces of northwestern Iran to examine the presence infection of . Specimens were obtained by swabbing from 140 mares (70 from each province) and 20 stallions (10 from each province) which were apparently healthy, and their DNA was analyzed using quantitative PCR assay detecting the element of the bacteri...
MacNeill AL, Micheloud JF, Parvin R, Gjessing M, Airas NA, Sant'Ana FJF, Adamek M.Zoonotic poxviruses, including monkeypox virus (MPV), the causative agent for Mpox disease, have gained significant media and scientific attention due to recent outbreaks in human populations across the globe. The increase in human cases of poxvirus infection is not unexpected, as routine vaccination against smallpox (a disease caused by the poxvirus variola virus, which cross protects against other orthopoxviruses) was discontinued in the 1980s after its eradication. Large numbers of vertebrate and invertebrate species are susceptible to infection by . Clinical signs and histologic lesions ca...
Sillence MN, Holt K, Li FI, Harris PA, Coyle M, Fitzgerald DM.Ecdysterone controls moulting and reproduction in insects, crustaceans, and helminths. It is also produced by many plants, probably as an insect deterrent. The steroid is not made by vertebrates but has anabolic effects in mammals and could be useful for treating sarcopenia in aged horses. However, ecdysterone is banned in horseracing and equestrian sports, and with no limit of reporting, the risk of unintended exposure to this naturally occurring prohibited substance is a concern. To explore this risk, pasture plants and hay samples were analysed for ecdysterone content, as well as samples of...
