Infectious diseases in horses encompass a range of illnesses caused by bacteria, viruses, fungi, or parasites. These diseases can affect various systems within the equine body, leading to symptoms that range from mild discomfort to severe systemic illness. Common infectious diseases in horses include equine influenza, strangles, equine herpesvirus, and West Nile virus. These diseases can be transmitted through direct contact with infected animals, contaminated surfaces, or vectors such as insects. Understanding the mechanisms of transmission, pathogenesis, and immune response is essential for effective prevention and control. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, diagnosis, treatment, and management of infectious diseases in horses.
Banks KL.The monocytes of horses infected with equine infectious anemia virus were shown by their failure to migrate from capillary tubes and their increased adherence to erythrocytes to be activated.
Vanderwagen LC, Pearson JL, Franti CE, Tamm EL, Riemann HP, Behymer DE.As a result of the continuing threat of Venezuelan equine encephalomyelitis (VEE), a study was made to determine if revaccination against VEE (TC-83 vaccine) was feasible and if revaccination could be incorporated into other routine vaccination practices. Of the horses given annual vaccination with bivalent western equine encephalomyelitis (WEE) and eastern equine encephalomyelitis (EEE) vaccine, 57% retained detectable serum-neutralizing (SN) antiboyd titers for VEE 18 months after the initial VEE vaccination was given. Of horses with no record of WEE-EEE vacinnation, 100% retained detectable...
Drudge JH, Lyons ET, Wyant ZN, Tolliver SC.The occurrence of 2nd and 3rd instars of Gasterophilus intestinalis and Gasterophilus nasalis was determined in 476 horses during the 22-year period from 1951 to 1973. Overall, G intestinalis infected 98.7% of the horses and averaged 168/horse; whereas G nasalis infected 80.7% of the horses and averaged 52/horse. Aggregate average total numbers for G intestinalis ranged from a low of 50 in September to a high of 229 in March, and for G nasalis, from a low of 14 in September to a high of 82 in February. Horses were infected by 2nd or 3rd instars of both species on a year-round basis. Differenti...
Zafracas AM.This paper describes sixteen cases of Candida infection of the genital tract in Thoroughbred mares. Clinical signs and histopathological lesions of the disease are described and the results of treatment with Lugol's solution and Nystatin are given.
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.
Trexler PC, Thomson GR.A method of rearing germ-free gnotobiotic foals is described. To date, four foals have been infected with rhinopneumonitis and the only clinical signs of infection have been a transient fever and leukopaenia; no detailed results are, as yet, available.
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.
Clark TL.The rarity of equine ovarian neoplasms is attested to by the lack of reports in the literature. However, sixteen cases have been diagnosed at the Iowa State University Veterinary Hospital in the last 3 years and, of these, the granulosa-cell tumour was the most common. A study of the clinical and subsequent histories of these and other mares reveals some common findings as to age, breed, reproductive status, clinical signs, and post-surgical reproductive capability.
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...
Burrows R, Goodridge D.The EHV-1 viruses of fetal origin grew better and had a wider tissue culture host range than those isolated from horses with respiratory diseases. Comparisons of a fetal isolate (F/304) and a respiratory disease isolate (R/NM-3) in partly immune horses showed that the F/304 virus infected horses more readily, grew better in the nasopharynx, was more likely to cause abortion, and was excreted to a greater extent into the environment.
Platt H.Many infections of the equine placenta and fetus result from ascending spread along the cervical canal. Most abortions due to infection occur during the later stages of pregnancy and the possible effects of intrauterine infection on the developing fetus and young foal are discussed.
Barban PS, Gol'din RB, Misenzhnikov AV, Prusakova ZM, Pantiukhina AN.The authors present the results of immunization of horses-producers with a commercial antigen and the yolk culture of the living R. sibericus (strain K1) for the purpose of obtaining specific immune sera for many purposes. It was shown that the original combined scheme of immunization and reimmunization of horses, successfully approved in the preparation of immune sera to Rickettsia prowazeki also proved to be highly effective for obtaining the antisera to R. sibericus. Sera obtained after the primary immunization of horses could be successfully used as diagnostic sera, but they were of no use...
Malmquist WA, Becvar CS.Equine infectious anemia (EIA) cell antigens prepared from infected equine spleen, equine leukocyte cultures or a persistently infected equine dermis cell line contained at least two serologically reacting components. For convenience one component was designated as soluble antigen (SA) and the other as cell-associated antigen (CAA). The SA appeared as a single component when it was prepared from EIA virus precipitated from infectious tissue culture fluid with polyethylene glycol and ether treated but it was mixed with CAA when the source was infected cells. Cytolytic or mechanical disruption o...
Rott R, Becht H, Orlich .Influenza virus Equine 1 (A/equine/Prague/56) has a hemagglutinin which is antigenically related to the hemagglutinin of fowl plague virus strain Rostock (FPV) and a neuraminidase which cross-reacts with the enzyme of virus N (A/chick/Germany/49). After a single injection of chickens with Equine 1 virus no hemagglutination inhibiting (HI) and neutralizing antibodies against FPV can be demonstrated, although the birds are fully protected against a lethal dose of FPV. HI and neutralizing antibodies against FPV appear after a second injection of Equine 1 virus several weeks after the first one. L...
Harrington R.During 2 years (fiscal years 1973 and 1974), microscopic agglutination tests were performed on 12,565 serums from cattle, swine, horses, deer, sheep, and goats for the detection of leptospiral antibodies. The most frequent presumptive infecting serogroups were Hebdomadis, Pomona, Autumnalis, Ballum, Australis, and Canicola.
Calisher CH, Maness KS.During the summer and fall of 1971, epizootic and epidemic Venezuelan equine encephalitis was detected in Texas. Isolates of epizootic (IB) and vaccine (TC-83) strains were distinguished by virulence of the former for guinea pigs. Vaccine virus was isolated from 1 to 14 days after vaccination and neutralization tests demonstrated the appearance of antibody about a week after vaccination. Viremia titers of subtype IB in horses ranged from 2.2 to 8.3 log10 suckling mouse intracranial 50% lethal doses per ml. Of 101 equines from which Venezuelan equine encephalitis virus (IB or TC-83) strains wer...
Jaeschke G, Lange W.In this paper three outbreaks of equine influenza in Berlin (Germany) in the years of 1988, 1989 and 1991 are discussed, reporting mainly clinical, hematological, virological and some epizootiological aspects. We have detected variations from the traditional pattern of equine influenza, whereby the main clinical symptoms like cough or fever were absent in several cases. If cough was found, it was moist. Furthermore a mucous nasal discharge was present in a number of cases for a period of 4-5 days. Extreme neutropenia, lymphocytosis and predominantly an unchanged level of monocytes were observe...
Allen BV, Frank CJ.MOST viral infections in animals, including man, have been
shown to alter the absolute and relative numbers of circulating
leucocytes. This usually causes a lymphopenia or neutropenia
but, occasionally, a lymphocytosis occurs (Gresser and Lang
1966). Several studies and reviews of respiratory viral
infections in horses have noted changes in the blood pictures
of infected animals, particularly during the early stages of the
disease (Steck and Gerber 1965; Gerber 1966, 1969; Bryans
and Gerber 1972; Hofer, Steck and Gerber 1978). The
transient nature of the leucocyte response is, probabl...
Hollyer JA, McGuinness E, Bowers LC, Didier ES, Giudice C, Perl DP, Fogarty U.A case of encephalitis of unknown origin in the horse was investigated. Postmortem examination findings revealed a nonsuppurative granulomatous meningoencephalitis in the right hemisphere of the cerebral cortex. Testing for West Nile virus, equine herpes virus, equine infectious anemia, , , and were negative. The horse had a titer for , and sections from the affected area of the brain tested positive for the organism using both polymerase chain reaction (PCR) and immunohistochemistry. Amplicons generated using PCR were sequenced, and genotype II was identified. This is the first case of gen...
Brumbaugh GW.The goal of antimicrobial drug use is quite specific. Consideration of many microbe-related, host-related, and drug-related factors is necessary for appropriate selection and use of antimicrobial drugs in equine patients. The concepts and data presented in this article demonstrate that fact. At the risk of oversimplification, "The bug denotes the drug, and the horse directs the course."