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.
Callow LL, McGregor W, Rodwell BJ, Rogers RJ, Fraser GC, Mahoney DF, Robertson GM.An indirect fluorescent antibody (IFA) test for the diagnosis of Babesia equi infections was evaluated. Antigen prepared by conventional methods was of high quality in one instance and of lesser quality in a second when possible autofluorescence of the horse blood caused inconvenience in reading tests. Tests on 14 horses shown by parasitological means to be either infected (9) or uninfected (5) produced reactions at dilutions of 1/270 to 1/7290 for infected and at 1/10 to 1/90 for uninfected animals. The accuracy of the test was further demonstrated during investigations of 701 horses in 3 sta...
Hartley WJ, Dixon RJ.Twenty-nine cases of EHV1 infection occurred on a property, mainly in full term foals. Some foals were stillborn, some were born alive but weak and soon died and others were healthy at birth, became ill and died within 3 days of birth. Apart from voluminous, oedematous and atelectic lungs there were no gross lesions. Microscopically the lungs showed oedema, pneumonitis and bronchiolitis with intranuclear inclusions and, in many of the foals that survived over 6 hours, there was also hyaline membrane formation. Microscopic lesions were also seen in the liver, adrenal, thymus and spleen of some ...
Haliburton JC, Vesonder RF, Lock TF, Buck WB.Signs and lesions characteristic of equine leucoencephalomalacia were produced in one of two donkeys given corn cultured with Fusarium moniliforme Sheldon. Gross and histopathologic lesions of the cerebrum included an extensive necrotic cavitation within one cerebral hemisphere, disruption and rarefication of the subcortical white matter, prominent perivascular hemorrhage, and some mononuclear cell perivascular cuffing. Another donkey and three rabbits fed the cultured corn did not develop characteristic signs or lesions of the toxicosis. Chick bioassay studies indicated that the cultured corn...
Prescott JF, Markham RJ, Johnson JA.Transformation of peripheral blood lymphocytes from pony foals vaccinated and subsequently infected with Corynebacterium equi was studied. Three foals were vaccinated on two occasions using a formalinized C. equi vaccine with aluminum hydroxide as an adjuvant. Three nonvaccinated foals served as controls. Foals were challenged intratracheally with 9 x 10(9) C. equi six weeks after the initial vaccination. Foals survived this infection for one to two weeks. Significant lymphocyte transformation in response to C. equi antigens was detected in two vaccinated foals at the third week after initial ...
Murphy J, Young S.Sudden unilateral blindness occurred in a 7-year-old grey gelding Quarterhorse. Ophthalmoscopy revealed a pigmented mass arising from the nasal ciliary body of the right eye and extending around the posterior surface of the lens, and there were pigmented particles in the vitreous. Examination of the enucleated globe showed a circumscribed, black, dense and symmetrically ovoid mass with sessile attachment to the nasal ciliary region and extension to posterior lens capsule, vitreous and along the vitreal face of the detached retina to the optic papilla. The mass was composed of heavily pigmented...
Pascoe RR.The epidemiology of dermatomycocis due to Trichophyton equinum var autotrophicum was studied in a number of thoroughbred stables in south-east Queensland. The significant factors in the epidemiology were defined. The infection was readily transmitted, particularly by infected saddle-girths, on which the fungus could survive for 12 months. Mild abrasion from the saddle during work favoured the development of lesions and prolonged the recovery period. A pronounced age and seasonal incidence of the disease was demonstrated as young horses under the age of 3 years were most susceptible, and the ma...
Hirsh DC, Smith BP.Horses in a riding stable sporadically excreted Salmonella agona, S anatum, and S newington in the feces. The three serotypes were isolated from apparently normal horses. The horses were sampled (the number sampled varied between 10 and 21) six times throughout a 13-month period. The greatest percentage of the horses (12 of 19, or 63%) were found to be excreting salmonella in September. Among the 12 horses excreting salmonella during this month, 8 (67%) were found to be excreting S agona.
Moreland AF, Gaskin JM, Schimpff RD, Woodard JC, Olson GA.Pregnant Rhesus monkeys were infected via instillation of influenza, mumps and western equine encephalomyelitis viruses respectively into the amniotic sacs at approximately 90 days gestation to determine if fetal infections would occur. Virus was recovered from fetal tissues after seven days in 100% of the exposed animals. Thus, the viruses are capable of causing fetal infection. Rhesus monkey fetuses were inoculated with influenza, mumps and WEE viruses by the direct intracerebral route at approximately 90 days gestation to determine possible teratogenicity of the viruses. influenza virus cau...
Smith BP.Salmonellosis in horses may result in fever, anorexia, and depression without concurrent diarrhea or other obvious gastrointestinal abnormalities and should be considered in cases of fever of unknown origin. The syndrome also is characterized by neutropenia, usually with a left shift, and growth of small numbers of salmonella from feces cultured in selenite enrichment broth. Repeated culturing may be necessary to isolate the organism. All six affected horses of this report recovered in 3 to 7 days without specific therapy.
Ribeiro HS, Larangeira NL, Paiva F.The authors sacrificed fifty-five horses originated from the "Pantanal", lowlands in the State of Mato Grosso in two different periods, droughty period and flooded and they described for the first time the Dictyocaulus arnfieldi in Mato Grosso. Relationship between droughty and flooded periods proved not to occur.
Sahu SP, Dardiri AH, Rommel FA, Pierson RE.Survival of bacteria that cause contagious equine metritis (CEM) was evaluated in Amies modified transport (AMT) medium, in AMT medium with charcoal, and in Stuart transport medium at 37, 22, 4, and -70 C. The CEM bacteria suspended in transport media survived at 22, 4, and -70 C for longer periods in AMT medium with charcoal than they did in AMT and Stuart transport media. In 1 day, the number of bacteria in exudate stored in the absence of any transport medium decreased 15-fold at 22 C and twofold at 4 C. The CEM bacteria were isolated from exudate on cotton-tipped swabs from all three trans...
English AW.The seasonal changes in longevity on herbage of the infective larvae of strongylid nematodes of the horse were studied. During the summer months, 1% of the larvae survived on herbage for 2-3 weeks, with 0.2% still viable for a further 2-3 weeks. Equivalent survival periods in winter were 7-11 weeks and over 11 weeks respectively. During spring and autumn, larvae survived for periods varying from 3-8 weeks. On Rhodes grass (Chloris gayana) growing vigorously in the summer of 1976, the majority of larvae remained in the lowest layers of the pasture, within 10 cm of the soil surface. Very few rea...
Singh BR, Chandra M, Agrawal RK, Nagrajan B.The present study on antigenic competition among somatic 'O' antigens of different Salmonella groups (A, B, C1, C2, D and E1) in mares revealed that the immune response to most of the antigens was not (A, B, C2) or little (C1, D) affected by antigenic competition. However, E1 group antigen, which induced high antibody titres (Avg. 12967.3) when given alone, produced almost 3.5 log2 lower antibody titres on giving with other antigens, indicating the antigenic competition among some Salmonella group antigens. The antigenic competition varied for different antigens even of the similar chemical na...
Remzi M, Buchsteiner R, Djavan B, Hittmair A, Seitz C, Klingler C, Marberger M.Actinomycosis of the urogenital tract is rare and predominantly an infectious disease of horses, cattle, swine, and humans. This case report describes isolated actinomycosis of the hydrocele wall presenting as an inflamed right-sighted hydrocele.
Uppal PK, Yadav MP, Singh BK, Prasad S.A progenital disease encountered at one equine stud farm at Bangalore in Southern India during 1987 was investigated and confirmed as equine coital exanthema on the basis of characteristic lesions and clinical symptoms, isolation of equine herpes virus-3 (EHV-3) from the scabs collected from animals having active lesions and demonstration of neutralizing antibodies in the sera of recovered mares and stallion. This is the first authenticated report of the occurrence of equine coital exanthema in India due to EHV-3.
Hemida MG, Alhammadi M, Daleb A, Alnaeem A.African horse sickness virus (AHSV) is one of the most devastating viral diseases of the family Equidae. Infection with AHSV threatens not only the Saudi equine industry but also the equine industry worldwide. This is due to the high morbidity and mortality rates among the infected population of up to 100%. The World Organisation for Animal Health (OIE) lists AHSV among its notifiable diseases; this requires Member Countries to monitor the situation with regard to AHSV very carefully in order to avoid the spread of the virus. The OIE also suggests the systematic monitoring of AHSV in the equin...