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Topic:Infectious Disease
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.
Suspected red maple (Acer rubrum) toxicosis with abortion in two Percheron mares. Horses develop severe and often fatal hemolytic anemia after ingesting dried leaves from red maple (Acer rubrum) trees. Toxicosis appears related to an unknown oxidant present in the dried or wilted leaves. This case report describes 2 horses that aborted and developed fatal hemolytic anemia after consuming wilted leaves from red maple (Acer rubrum). While an absolute diagnosis was not confirmed due to lack of proper antemortem and postmortem examinations, red maple toxicosis appeared a reasonable diagnosis based on clinical signs and laboratory findings. Other differentials include equine inf...
Besnoitiosis in a horse. Besnoitiosis was confirmed in a pony which presented with inspiratory dyspnoea, scleroderma and ventral oedema. Numerous cysts were visible in the sclerae. Histological examination of the skin confirmed the presence of numerous cysts. The parasite could not be transmitted by subcutaneous injection of homogenised skin from the infected horse to rabbits and a horse. Ultrastructural morphology of the crescent-shaped bradyzoites was not compatable with Besnoitia besnoiti or B. jellisoni and it is proposed that the infection was caused by B. bennetti.
An occurrence of equine transport pneumonia caused by mixed infection with Pasteurella caballi, Streptococcus suis and Streptococcus zooepidemicus. An acute death occurred in a racehorse with pneumonia after long-distance transportation in December, 1990. Pasteurella caballi, Streptococcus suis and Streptococcus zooepidemicus were isolated from the lung at high rate. Specific antigens of these bacteria were also demonstrated immunohistologically in the pneumonic lesion. These findings indicated that the disease is equine transport pneumonia caused by a mixed infection of the three bacterial species. This is the first report on the isolation of P. caballi and S. suis from a racehorse in Japan.
Serological evidence of equine arteritis virus in donkeys in South Africa. This paper reports the first serological evidence of exposure of donkeys to equine arteritis virus. Seven hundred and thirty-four serum samples collected between 1989 and 1992 from donkeys in different areas of South Africa were examined for the presence of antibodies against this virus by a microneutralization test. Seventeen percent of serum samples tested positive. The distribution of seropositive animals varied from none in the western Cape Province and the Transvaal Highveld to 30% in the northern Transvaal. The country-wide distribution of serologically positive donkeys suggests a longst...
Equine influenza virus from the 1991 Swedish epizootic shows major genetic and antigenic divergence from the prototype virus. The antigenic properties of H3N8 equine influenza virus from the Swedish epizootic of 1991 differ from those of A/eq 2/Fontainebleau/79 (representative of the Swedish vaccine strain) in hemagglutination inhibition tests. The amino acid sequence of the hemagglutinin (HA) of an isolate from the 1991 outbreak was deduced from the nucleotide sequence and comparison was made to the A/eq 2/Fontainebleau/79 strain. Twenty-three amino acid substitutions were found, 10 mapping onto areas of the HA known to bind antibodies in human H3 influenza viruses. The amino acid changes together with the serologic...
[Foal diseases and foal loss]. An investigation was carried out upon occurrence and course of infectious and non infectious diseases as well as the mortality in foals born and raised at the State Stud Marbach/Lauter between 1982 and 1991. The foals have been investigated from birth to weaning, they consisted of 177 Thoroughbred Arabians and 285 German Warmblood foals (total 462 foals). The diseases were divided into pre-, peri- and postnatal according to their known or assumed cause and onset. There was a preponderance of prenatal diseases (11.25%) whereas the perinatal rate was 1.30% and the postnatal rate of diseases was ...
[Equine rhinopneumonitis: molecular epidemiology and diagnosis by molecular probes prepared from organs]. The authors briefly review the clinical forms of equine rhinopneumonitis and indicate changes in the nomenclature of equine herpesviral infections. The value of restriction profiles for epidemiological studies is described, taking as an example the strains of virus isolated in France. A technique is given for preparing molecular probes, as well as the application of these probes in direct diagnosis from biological specimens.
An outbreak of strangles in young ponies. A natural outbreak of strangles occurred in a group of 19 young experimental ponies. The disease was diagnosed in 11 of them within two days of their arrival at Glasgow University veterinary school and five others developed clinical signs within a further four days, a morbidity rate of 84 per cent. All of the affected ponies had typical signs of strangles including dullness, anorexia, pyrexia, regional lymphadenitis, occasionally with rupture of the lymph node, conjunctivitis and a mucopurulent nasal discharge. Nine of the affected ponies were destroyed during the clinical phase of the disease...
Treatment of respiratory infections in horses with ceftiofur sodium. Ceftiohr sodium was evaluated as a therapy for respiratory
infections in horses. This cephalosporin antimicrobial was
administered intramuscularly every 24 h and at a dose of 2.2
mglkg (1.0 mgllb) of body weight. The efficacy of ceftiofur
sodium was compared with that of a positive control drug,
ampicillin sodium (recommended dose of 6.6 mg/kg [3 mg/lb],
given every 12 h). Both treatments were continued for 48 h
after clinical symptoms were no longer evident (maximum of
10 days). Fifty-five (55) horses with naturally acquired
respiratory infections were included in the study; 28 were
...
Proceedings of the John P. Hughes International Workshop on Equine Endometritis. Davis, California, August 1992. The paper is a report from a workshop discussing equine endometritis, a condition affecting horse fertility. The event was held in honor of Professor John Hughes and his significant contributions […]
Responses of ponies to equid herpesvirus-1 ISCOM vaccination and challenge with virus of the homologous strain. An experimental (ISCOM) vaccine previously shown to protect hamsters from lethal challenge with equid herpesvirus-1 (EHV-1), was tested in horses. Vaccination with EHV-1 ISCOMs induced serum antibodies to the major virus glycoproteins gp10, 13, 14, 17, 18 and 21/22a, whereas antibody responses to gp2 were weak or absent. High levels of virus neutralising antibody of long duration were induced, but did not prevent challenge infection with virus of the homologous strain. However, in the vaccinated ponies there was a significant reduction in clinical signs, nasal virus excretion and cell associat...
Pathogenicity of a thymidine kinase-deficient mutant of equine herpesvirus 1 in mice and specific pathogen-free foals. Both intranasal (i.n.) and intracerebral (i.c.) inoculation of mice with wild-type equine herpesvirus type 1 (wt EHV-1) caused clinical signs and mortality. Virus could be recovered from target organs (turbinates, lungs and blood) for several days. By contrast, the thymidine kinase (TK)-deficient deletion mutant PR1 produced markedly less clinical disease following both i.n. and i.c. inoculation, and, in particular, no mortality occurred. PR1 did, however, establish productive infections following either route of inoculation. High titres of virus were recovered from target organs although viru...
Characterization of equine infectious anemia virus dUTPase: growth properties of a dUTPase-deficient mutant. The putative dUTPase domain was deleted from the polymerase (pol) gene of equine infectious anemia virus (EIAV) to produce a recombinant delta DUpol Escherichia coli expression cassette and a delta DU proviral clone. Expression of the recombinant delta DUpol polyprotein yielded a properly processed and enzymatically active reverse transcriptase, as determined by immunoblot analysis and DNA polymerase activity gels. Transfection of delta DU provirus into feline (FEA) cells resulted in production of virus that replicated to wild-type levels in both FEA cells and fetal equine kidney cells. In con...
Leptospiral abortion and leptospiruria in horses from the same farm. Leptospirosis was documented as the cause of abortion in a 5-year-old mare. Leptospires were detected in tissue specimens from fetal kidneys and from placenta by histologic evaluation of silver-stained sections. Antibodies against Leptospira interrogans serovar pomona were detected in fetal serum at a titer of 1,600 by use of a microscopic agglutination test. The mare had serum titers of 6,400; 0; 400; 800; 3,200; and 6,400 to L interrogans serovars bratislava, canicola, grippotyphosa, hardjo, icterohaemorrhagiae, and pomona, respectively. A serologic survey identified titers of at least 6,400...
Studies on the substrate specificity of the proteinase of equine infectious anemia virus using oligopeptide substrates. The proteinase of the equine infectious anemia virus (EIAV), a lentivirus closely related to human immunodeficiency virus (HIV), was purified from concentrated virus. The specificity of the enzyme was characterized using oligopeptides representing naturally occurring cleavage sites in the Gag and Gag-Pol polyproteins. The length of the substrate binding pocket was found to be 1-2 residues longer than that of HIV proteinases. Although the EIAV and HIV proteinases cleaved most of the peptides at the same bond, some were hydrolyzed by only the EIAV enzyme. Oligopeptides representing cleavage site...
[Equine influenza outbreaks with viral antigenic drift in Berlin 1988-1991]. 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...
Aspergillosis granuloma in the mediastinum of a non-immunocompromised horse. A National Show Horse with a mediastinal granuloma was presented with clinical signs which included fever, nasal discharge and cough. The mediastinal mass was identified radiographically and ultrasonographically. A presumptive diagnosis of aspergillosis was made following isolation of Aspergillus spp. from both transtracheal aspirate and bronchoalveolar lavage fluid samples and agar gel immunodiffusion (AGID) identification of serum antibody to Aspergillus spp. The diagnosis was confirmed by histopathologic examination of the mediastinal mass obtained at necropsy examination.
Seroepidemiological survey of chlamydial infections in light horses in Japan. To investigate the overall prevalence of chlamydial infections in light (i.e. non-draught) horses in Japan, 599 sera obtained from 12 localities in 1991 were tested for complement fixation antibodies. The mean antibody positive rates of the all sera were 15.2% (91/599) and the regional positive rates were higher in Honshu (19.1%, 48/251) and Kyushu (20.0%, 20/100) than in Hokkaido (9.3%, 23/248). In Honshu, the highest rate (56.0%, 28/50) was observed in Utsunomiya. Analysis of the positive rate in different age groups showed that the 2-5 years age-group had the highest prevalence of chlamydia...
Characterization of serum lysosomal enzymatic activities. III. Effect of infectious influenza in Egyptian equines. An outbreak of infectious influenza was recognized in Menofeia governorate in October 1989. Eight naturally influenza infected as well as 8 healthy control horses, mules and donkeys were selected for collection of blood and sera separation to estimate four lysosomal enzymatic activities and to describe the clinical findings, which were fever, congested nasal, conjunctival membranes and cough. Bronchopneumonia followed later with bilateral purulent nasal discharge as a complication in 2 donkeys. Thereafter laboured breathing occurred. Therefore a therapeutic penicillin-streptomycin dose was inj...
[Post-epizootic activity of Western equine encephalitis virus in Argentina]. It is shown here the WEE virus activity in ARgentina in 1983-1986 post-epizootic period. A surveillance system was established by the equine case notification and the sentinel animal method. Among the thirteen equine focus notified between September 1983-September 1985 in Córdoba and Santa Fe Provinces, 5 presumptive cases out of 16 sick horses were confirmed by the hemagglutination inhibition test for WEE epizootic virus. Twenty eight notified human cases were studied with negative results. The neutralizing antibody (Ac NT) prevalence among sentinel horses in Córdoba Province (4%) was lower...
Effect of influenza A/equine/H3N8 virus isolate variation on the measurement of equine antibody responses. This study has tested the effect of using homologous or heterologous equine influenza A virus isolates to evaluate serum antibody levels to influenza A virus in vaccinated and naturally-infected horses. In addition, the potential effect of antigenic selection of virus variants in egg versus tissue culture propagation systems was studied. Serum antibody levels in samples from horses recently infected with a local influenza A virus isolate (A/equine 2/Saskatoon/1/90) or recently vaccinated with a prototype isolate (A/equine 2/Miami/1/63) were assessed by hemagglutination inhibition and by single...
The identification of equid herpesvirus 1 in paraffin-embedded tissues from aborted fetuses by polymerase chain reaction and immunohistochemistry. Paraffin-embedded organ samples from 28 aborted fetuses and three foals, partly archival and partly sampled in 1991, were examined by polymerase chain reaction (PCR) and immunohistochemistry for the presence of DNA and antigens, respectively, specific for equine herpesvirus 1 (EHV-1). Virologic examination had been performed on 23 of the aborted fetuses. DNA fragments specific for EHV-1 were identified by PCR, and EHV-1 antigens were identified in situ by immunohistochemistry, with an agreement between the methods of 94% (kappa = 0.85). Compared with virus isolation, PCR agreement was 87% (kap...
Clostridium septicum septicemia in a neonatal foal with hemorrhagic enteritis. Clostridium septicum was isolated by anaerobic culture of blood collected from a 3-day-old foal with hemorrhagic enteritis and signs suggestive of septicemia. The foal responded well to treatment with intravenous fluids, antibiotics, plasma, and oral gastrointestinal protectants. One month after apparent complete recovery from the septicemia and hemorrhagic enteritis, the foal was euthanized during an acute episode of colic that was caused by severe, strangulating intestinal adhesions, thought to have formed as a result of peritonitis secondary to the hemorrhagic enteritis. The value of anaero...
