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Topic:Disease Outbreaks
Disease outbreaks in horses refer to the occurrence and spread of infectious diseases within equine populations. These outbreaks can be caused by various pathogens, including bacteria, viruses, and parasites, and can lead to significant health issues in affected horses. Common diseases that may result in outbreaks include equine influenza, equine herpesvirus, strangles, and equine infectious anemia. The transmission of these diseases can occur through direct contact, environmental exposure, or vectors such as insects. Disease outbreaks can have substantial impacts on horse health, welfare, and the equine industry as a whole. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, transmission dynamics, and management strategies associated with disease outbreaks in equine populations.
Equine herpesvirus abortion in Australia 1977 to 1982. Until 1977 no case of abortion caused by equine herpesvirus 1 (EHV1) had been recorded in Australia although the virus, called equine rhinopneumonitis virus, had been known to have been present at least since 1962. Outbreaks of EHV1 abortion occurred in New South Wales in 1977 and in 1981. Sporadic cases of EHV1 abortion had been confirmed in some parts of Australia each year since 1975. It was concluded that an abortigenic subtype of EHV1 had been introduced to Australia in 1977 and that the previously endemic respiratory subtype occasionally caused abortion. Virus isolation in a variety of c...
Isolation of saprophytic Microsporum praecox Rivalier from sites associated with horses. Several M. praecox isolates of saprophytic origin were obtained in Belgium from horses and their surroundings. Visualization of macroconidia in dust collected in stables proved its saprophytic origin. A few strains were obtained from human cases of tinea corporis.
Outbreak of ragwort (Senecio jacobea) poisoning in horses. Five out of 20 horses (25 per cent) on one farm died from an acute hepatic encephalopathy typical of ragwort toxicosis. Circumstantial evidence implicated pasture rather than hay as the principal source of the toxic alkaloids. Plasma levels of gamma glutamyl transferase (GGT) were determined on three occasions in all surviving ragwort-exposed horses. Elevated GGT levels were a useful early indicator of hepatic damage although not all horses with this biochemical sign developed clinical disease.
Identification of carriers of Streptococcus equi in a naturally infected herd. During an outbreak of strangles in a population of research horses, 4 mares were identified as carriers of Streptococcus equi. Three of the mares had typical signs of strangles (severe regional lymphadenitis with or without rupture of abscessed lymph nodes). The 4th mare experienced episodes of serous to mucopurulent nasal discharge, but never had more than a mild degree of lymph node enlargement. Streptococcus equi was isolated from the abscessed lymph nodes and from nasopharyngeal swab specimens from the first 3 mares from 6 to 19 weeks after rupture of involved nodes. Streptococcus equi was...
Study of equine histoplasmosis farciminosi and characterization of Histoplasma farciminosum. A detailed clinical and mycological study of horse infections with Histoplasma farciminosum was conducted for the first time in the Middle East. The disease seems to prevail in endemic form in the region. In all of the cases studied the infection involved only the cutaneous lymphatics and skin tissue with extension to the regional draining lymph glands. The disease seems to impose serious economic impact in the infected areas. Full description and thorough characterization of both the mycelial form and the yeast phase of the causative fungus were made.
Laboratory investigations on equine influenza during the outbreak in Poland in 1980. Summary
The outbreak of equine influenza in Poland in 1980 was caused by an equine influenza virus antigenically related to the strain A/equine/Miami/63/Heq2, Neq2. This was confirmed by isolation of six strains of influenza virus from horses suffering from the acute form of the disease. About 45 % and 69 % of positive results were obtained in the HI test performed with sera taken from convalescent and affected animals, respectively. A relatively high level of antibodies against newly isolated equine influenza virus strains was found in 50 % of serum samples taken from the grooms. A relativ...
Caecal rupture in parturient mares. The pathology of 4 cases of caecal rupture in foaling mares is described. One of these animals died suddenly, probably when rupture occurred, and 3 survived for 5 to 8 h and died from acute peritonitis.
The pathogenesis of this type of injury is discussed and it is suggested that rupture may arise from the pressure of a foetal hind foot against the caecum when distended by local tympany.
Marker characteristics of Venezuelan encephalitis virus strains isolated before and after epidemics and equine epizootics in Middle America. Ninety-four strains of Venezuelan encephalitis (VE) virus isolated from sentinel hamsters exposed in the Middle American countries of Mexico, Guatemala, Belize, and Honduras were examined for the presence of virions with marker characteristics of strains that cause large epidemics and equine epizootics. Thirty-four strains came from before and 60 strains came from after the Middle American epidemics and equine epizootics of 1966 and 1969-1972. Twenty-three virion clones that resembled epizootic strains by hydroxylapatite chromatography and Vero monkey kidney cell plaque size determinations wer...
[Progressive course of spinal cord tumors]. The main clinical varieties of spinal cord and equine tail tumors are reviewed. Of 221 cases, the progressive course of the disease was recorded in 76,9%, slow-progressive course was observed in 68,1% and rapid-progressive in 8,8% of cases. It is stressed that in the presence of the progressive course of the disease there may occur different manifestations of the tumorous process of the spinal cord, the examination of which makes it possible to improve the diagnosis, particularly in the early stage of the spinal oncological process.
Analysis of antigenic variation in equine 2 influenza A viruses. Influenza outbreaks involving viruses of the H3N8 subtype (equine 2) often occur in vaccinated horses. For this reason, a series of influenza viruses of the H3N8 subtype were examined to determine if antigenic variation could be detected in isolates during the period 1963-81. Antigenic analyses with post-infection ferret sera and monoclonal antibodies showed that the haemagglutinins of recent isolates were antigenically distinguishable from the prototype A/eq/Miami/1/63 and that antigenically distinguishable groups of equine 2 viruses co-circulate in the horse population. Based on these studie...
Restriction endonuclease DNA fingerprinting of respiratory, foetal and perinatal foal isolates of equine herpesvirus type 1. DNA was prepared from 43 equine herpesvirus type 1 (EHV 1) isolates, 11 of which were from horses with respiratory disease, 22 from aborted equine foetuses, and 10 from foals that died perinatally. The restriction endonuclease DNA fingerprints of 10 of the 11 respiratory isolates, known with certainty to have been recovered from horses with respiratory disease, were entirely different from all but 3 of the 32 foetal or perinatal foal isolates. The exceptional respiratory isolate, EHV 1 Army 183, had a foetal (F) strain fingerprint but this virus cannot be said with certainty to have been isola...
Isolation of the contagious equine metritis organism from colts and fillies in the United Kingdom and Ireland. Between January 1978 and August 1982 the streptomycin resistant strain of the contagious equine metritis organism (CEMO) was isolated from 15 colts and two fillies in the United Kingdom and Ireland. A first season stallion was also suspected of having initiated an outbreak of contagious equine metritis (CEM) at the beginning of the 1982 breeding season. A detailed investigation of the breeding history of the dams and sires of each positive individual indicated that in a number of cases the CEMO was acquired either in utero or following transmission at the time of parturition. In several other ...
Variation in arbovirus infection rates in species of birds sampled in a serological survey during an encephalitis epidemic in the Murray Valley of South-eastern Australia, February 1974. There was extensive and exuberant breeding of waterbirds before and during an epidemic of arboviral encephalitis in the Murray Valley of south eastern Australia in 1974. As estimated by haemagglutination inhibition tests on 432 bird sera collected between 4th and 13th February, 1974, infection with Murray Valley encephalitis virus, Kunjin virus and possibly other flaviviruses was concentrated in species of the Order Ciconiiformes (55% positive) and Pelecaniformes (41%), compared with only 5% in Anseriformes. Although Sindbis virus infections were also highest in these 2 Orders (56% and 46%, re...
Horse erythrocyte glycoprotein-latex reagent that reacts with infectious mononucleosis heterophile antibody. A sialoglycoprotein from horse erythrocytes was isolated in essentially homogeneous form and found to contain the neuraminidase-sensitive determinant of the horse erythrocyte for Paul-Bunnell heterophile antibodies of infectious mononucleosis. This reactivity was retained after covalent coupling of the antigen to latex particles. The latex reagent has greater stability (greater than 3 years) than either fresh or preserved horse erythrocytes. It can be used in a direct slide test; no absorption of the serum is necessary. The new test compared favorably with some standard tests for infectious mo...
