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.
Carvalho M, Derse D.Equine infectious anemia virus (EIAV) is a lentivirus that causes a chronic disease of horses characterized by cyclic episodes of fever, anemia, and viremia. Although the genome and promoter of EIAV are much less complex than those of its relatives the primate immunodeficiency viruses, the cellular proteins that activate and regulate transcription of EIAV have not yet been identified. In this report, we show by electrophoretic mobility shift assays and DNase I footprinting that the EIAV promoter contains multiple binding sites for ubiquitous, cell type-specific, and inducible cellular proteins...
McClure SR, Hooper RN, Watkins JP.A 13-month-old Quarter Horse colt sustained a puncture wound to the frog region of the foot, which penetrated the navicular bursa and distal interphalangeal joint, 7 days prior to examination. A street-nail procedure was performed to debride the tract and provide drainage of the navicular bursa and distal interphalangeal joint. An indwelling lavage system was placed through the dorsal aspect of the joint and antimicrobials were infused intermittently to supply a high local concentration of drug and to frequently lavage the distal interphalangeal joint and navicular bursa.
Holman PJ, Frerichs WM, Chieves L, Wagner GG.Culture of horse blood for Babesia caballi identified four carrier horses among nine previously infected horses. Three of the carriers had no detectable parasitemias on stained blood smears, and sera from two carrier horses were complement fixation test negative. Three cultures were continuously cultivated. Cryopreserved fourth-passage B. caballi was successfully reestablished in vitro. Blood from a 10th horse previously subinoculated with blood from a suspected carrier was cultured, with negative results.
Meireles MC, Riet-Correa F, Fischman O, Zambrano AF, Zambrano MS, Ribeiro GA.Equine pythiosis was studied in five animals from two farms located in a swampy region of southern Brazil (Rio Grande do Sul State). Granulomatous lesions exuding necrotic material and containing a central yellow and firm tissue core, the 'kunker', were observed on the top of the nose of one horse, on the abdomen of two horses and on the hind limbs of two other animals. Direct microscopic preparations, histopathological examination of lesion material, and macroscopic and microscopic characteristics of the isolates confirmed the diagnosis of pythiosis. Surgical intervention of the inflammatory ...
Gupta AK, Yadav MP, Uppal PK, Mumford JA, Binns MM.Two A/Equi-2 (H3N8) isolates were obtained during the 1987 Indian equine influenza epizootic. The sequence of the Ludhiana/87 HA1 gene revealed that this isolate was very similar to recent European and North American isolates of equine influenza. In contrast, the Bhiwani/87 HA1 gene was nearly identical to the Miami/63 prototype H3 sequence. These results support the antigenic analysis previously carried out on these isolates using monoclonal antibodies. However, the finding that Bhiwani/87 is so similar to Miami/63, coupled with the finding that equine H3N8 influenza viruses have previously b...
Monzón CM.A direct agglutination test is described to diagnose 'Mal de Caderas' caused by Trypanosoma evansi. The antigen used was a suspension of trypsin-treated parasites stabilized with formalin. The test was evaluated in horses with both natural and experimental infections. Test sensitivity and specificity were 94 and 97%, respectively. Treatment of serum with 2-mercaptoethanol before testing permitted the differentiation of IgM and IgG antibodies, and possible differentiation of current infection from past exposure to the parasite. The antigen was stable over a 6-month evaluation period and also sh...
Smith KC, Tearle JP, Boyle MS, Gower SM, Mumford JA.Equid herpesvirus-1 (EHV-1; Ab4 isolate) was inoculated unilaterally into the cavum vaginale of four pony colts under general anaesthesia. The animals were monitored daily for evidence of scrotal or testicular swelling and euthanased electively on days 3, 4, 6 and 12 after infection. Detailed pathological examination of the male genital tract was carried out. In animals examined at days 3 and 4 after infection, replication of EHV-1 was detected bilaterally in mesothelial and endothelial cells of the parietal and visceral vaginal tunics. The mesothelial infection had resolved by day 12 after in...
Touratier L.There is increasing interest in many parts of the world in trypanosomoses other than those transmitted by tsetse flies, as shown by numerous research projects and field studies. The refinement of techniques for studying the behaviour of trypanosomes (techniques of molecular biology) in axenic culture or in the parasitised host has led to progress in diagnosis and immunology, and a rational approach to chemotherapy and chemoprophylaxis of these infections. Field trials of enzyme-linked immunosorbent assays in Africa, Asia and South America have shown that these tests may now be regarded as reli...
Hoffman DW, Colvin RA, Garcia-Blanco MA, White SW.A 25-nucleotide RNA with the sequence of the trans-activation response (TAR) element of equine infectious anemia virus (EIAV) was analyzed by biochemical methods and by one- and two-dimensional NMR spectroscopy. NMR, nuclease probing, and polyacrylamide gel migration rates show that the RNA consists of an A-helical stem capped by two non-Watson-Crick U-G base pairs and a compact four-nucleotide loop. The loop is stabilized by base stacking, with loop nucleotides C12 and C15 stacked upon U11 and G16, respectively. Near the 5' end of the molecule, the stem contains a bulge at nucleotide C2, most...
Sinclair R, Binns MM, Chirnside ED, Mumford JA.The N-terminal fragment comprising residues +1 to +50 (gB1-50) of equine herpesvirus type 1 (EHV-1) glycoprotein B was expressed as a glutathione S-transferase fusion protein in Escherichia coli. Recombinant gB1-50 (rgB1-50) was recognized in immunoblots by sera from rabbits immunized with EHV-1 and by convalescent-phase sera from horses with natural EHV-1 infections. An enzyme-linked immunosorbent assay (ELISA) for monitoring antibody levels against EHV-1 was developed by using rgB1-50, and its specificity was assessed with a panel of reference antisera against other equine viruses. A specifi...
Lun ZR, Fang Y, Wang CJ, Brun R.Trypanosomiasis caused by Trypanosoma evansi (surra) is a problem of great economic importance in livestock in China because it affects important working animals: buffaloes in the south and east, and horses and cattle in the north and west. In addition, buffaloes are an important source of meat and leather for the Chinese population. In the north and west, T. evansi is found mainly in camels, whereas in the east, the south and the southwest, it is primarily buffaloes, cattle and horses that are affected by this parasitic flagellate. Although trypanosomiasis is one of the most important parasit...
Rode HJ, Janssen W, Rösen-Wolff A, Bugert JJ, Thein P, Becker Y, Darai G.A gene was identified within the DNA sequences of the EcoRI DNA fragment N (4.3 kbp) of the genome of equine herpesvirus type 2 (EHV-2) coding for a protein (179 amino acid residues) homologous to the cytokine synthesis inhibitory factor (CSIF; interleukin 10) of the human and mouse, and to the Epstein-Barr virus (EBV) protein BCRF1. This finding is further significant evidence that the interleukin 10 (IL-10) and/or IL-10-like gene can indeed be present in the genomes of members of the herpesviral family.
Orino K, Saji M, Ozaki Y, Ohya T, Yamamoto S, Watanabe K.The effects of horse serum on the immunoassay of horse ferritin were investigated using two sandwich enzyme-linked immunosorbent assay (ELISA) systems. In System A, affinity-purified antibody to horse spleen ferritin and its conjugate with alkaline phosphatase were used as the first and second antibodies, respectively. In System B, whole antiserum and its conjugate with the enzyme were used. The recoveries of horse spleen ferritin added to horse sera were very low in either system (50-71% in System A; 42-79% in System B). However, heat treatment of the sera at 75 degrees C for 15 min improved ...
Ali S, Sugimoto C, Matsuda M, Sugiura T, Kanemaru T, Onuma M, Kamada M.Proteins of Babesia equi piroplasms were characterized. The piroplasms of B. equi were purified by lysis of infected horse erythrocytes with N2 gas cavitation followed by separation in Percoll density-gradient centrifugation. The relative molecular weights (Mr) of major proteins separated by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 18, 28, 30, 41, 43, 54, 66.5, and 96 kDa. Immunoblot analysis using serum from an experimentally infected horse revealed six immunodominant proteins of 15, 18, 28, 30, 41, and 96 kDa. Two immunodominant proteins of 18 and 28 kDa...
Rodriguez M, Hooghuis H, Castaño M.African horse sickness (AHS) is an infectious, non-contagious, highly fatal viral disease of Equidae, transmitted by arthropod vectors of the genus Culicoides, and endemic in Africa south and east of the Sahara. The disease is caused by a virus of the Reoviridae family, genus Orbivirus, and 9 serotypes have been recognized. Recent outbreaks of AHS in the Iberian peninsula and Northern Africa emphasize the need for accurate diagnosis and rapid implementation of control measures. In this paper, the epizootiological factors, clinical signs and necropsy findings of AHS are discussed, and an update...
Lew AM, Thomas LM, Huntington PJ.Sera of sixteen horses with clinical signs of EIA from six different outbreaks and sera of 100 uninfected horses were used to validate an ELISA for EIA diagnosis. The antigen used was a recombinant protein derived from the amino-terminal portion of the transmembrane envelope protein of EIA (gp45). Reactivity between positive and negative sera could be clearly distinguished. Comparison with the traditional agar gel immunodiffusion test (commonly called the Coggins test) showed that the ELISA was superior in sensitivity. Comparison of this ELISA with the FAST-ELISA system showed that the latter ...
Kita J.Epidemiological observations on the course and spread of equine influenza in Poland during the 1969 epizootic were carried out. The dynamics of the spread of the disease in the country are shown graphically by voivodship. The disease incidence and mortality rates for the entire country are also shown. The highest incidence of disease and mortality rates were found to be in November 1969. A/equi-2/Warsaw/69 was identified as the causal virus. It caused the largest epizootic in the country since 1954.
Beveridge WI.For 20 years after the influenza A virus was discovered in the early 1930s, it was believed to be almost exclusively a human virus. But in the 1950s closely related viruses were discovered in diseases of horses, pigs and birds. Subsequently influenza A viruses were found to occur frequently in many species of birds, particularly ducks, usually without causing disease. Researchers showed that human and animal strains can hybridise thus producing new strains. Such hybrids may be the cause of pandemics in man. Most pandemics have started in China or eastern Russia where many people are in intimat...
Corstvet RE, Gaunt SD, Karns PA, McBride JW, Battistini RA, Mauterer LA, Austin FW.An enzyme-linked immunosorbent assay (ELISA) was used to detect antigen in plasma and antibody in serum of 3 horses inoculated with Ehrlichia equi. Clinical signs, including rectal temperature, were correlated with the antigen and antibody detection. ELISA was very efficient in detection of serum antibody. Antigen detection using monoclonal antibodies to E. equi and ELISA should be considered as a diagnostic method.
DeVico AL, Issel CJ, Le Grice SF, Payne SL, Montelaro RC, Sarngadharan MG.The immunogenicity of the equine infectious anemia virus (EIAV) reverse transcriptase (RT) was examined by immunoblot assay with recombinant EIAV RT. All of the 19 sera from EIAV-infected horses tested contained antibodies that recognized EIAV RT and directly inhibited the polymerase activity of the enzyme. An examination of sera obtained sequentially from two experimentally infected animals revealed that anti-RT antibodies arise early in infection and increase in level. The appearance of the antibodies correlated with progression toward the asymptomatic period of infection.
Gautsch S, Beckmann G, Amtsberg G, Dieckmann M, Deegen E.100 faecal samples from clinically healthy horses of different age groups and feeding habits, 50 samples of faeces from horses suffering from enteropathy accompanied by diarrhoea and small and/or large intestine from 25 horses that had died after an intestinal disease were examined for the presence of Clostridium (Cl.) perfringens. The frequency with which Cl. perfringens was detected was 22% in clinically healthy horses, 32% in horses with diarrhoea and 52% in the dead horses. In two faecal samples from the horses with diarrhoea the microbial count of Cl. perfringens was ca. 10(6) cfu/g faece...
Mellor PS.African horse sickness (AHS) virus causes a non-contagious, infectious, arthropod-borne disease of equines and occasionally of dogs. The virus is widely distributed across sub-Saharan African where it is transmitted between susceptible vertebrate hosts by the vectors. These are usually considered to be species of Culicoides biting midges but mosquitoes and/or ticks may also be involved to a greater or lesser extent. Periodically the virus makes excursions beyond its sub-Saharan enzootic zones but until recently does not appear to have been able to maintain itself outside these areas for more t...
Bitsch V.A venereal disease usually designated equine coital exanthema (ECE) has been observed in horses all over the world. In a very few oases a virus, claimed to be the causative agent of the disease, has been isolated.
Nerren JR, Payne S, Halbert ND, Martens RJ, Cohen ND.Rhodococcus equi is an intracellular pathogen of macrophages that causes rhodococcal pneumonia in foals and immunocompromised people. Evidence exists that neutrophils play a vital role in resistance to infection with R. equi; however, the means by which neutrophils exert their effects have not been clearly defined. In addition to directly killing bacteria, neutrophils also may exert a protective effect by linking innate and adaptive immune responses. In the present study we evaluated the cytokine expression profiles of adult equine neutrophils in response to stimulation with isogenic strains o...
Pampiglione S, Baldelli R, Corsini C, Mari S, Mantovani A.The occurrence of a trichinellosis epidemic in the province of Reggio Emilia in 1975, the source of which was attributed to horse meat, led the authors to use this animal for experimental infections. By using the trichina strain isolated from the above outbreak, 4 horses were infected orally. All 4 animals became infected. The most affected muscles were the lingual, masticatory and neck ones. Meat from the 4 horses was subsequently fed to laboratory animals (rats, mice, guineapigs) and other domestic species (cats, dogs, pigs) and further infections were obtained. An attempt to infect also a s...
Finney S, Collins JA, Duggan V.The number of abandoned or otherwise neglected donkeys has significantly increased in Ireland in the recent past. The real or perceived capacity of the donkey to act as a reservoir of equine infectious disease, and thus pose an increased risk of disease transmission to horses and ponies, may be a factor in this increased abandonment and neglect. The authors here report on a field study exploring the infectious disease transmission threat the donkey poses to the general equine industry in Ireland through an examination of biosecurity standards and the views of horse and donkey exhibitors at nin...
Mawhinney I.Taylorella equigenitalis, the cause of contagious equine metritis (CEM), can be detected by culture but in recent years polymerase chain reaction (PCR) has also been used. In 2008, the World Organisation for Animal Health (OIE) Reference Laboratory for CEM in the United Kingdom set up a ring trial for laboratories to assess their ability to identify T. equigenitalis in laboratory-prepared samples because the identification of T. equigenitalis in the laboratory was recognised to be difficult. Freeze-dried culture suspensions in various combinations of any of T. equigenitalis, Taylorella asinige...
Bromberger CR, Costa JR, Herman M, Hernandez JM, Albertino LG, Alves CEF, Borges AS, Oliveira-Filho JP.Aural plaques have been linked to Equus caballus papillomavirus (EcPV). Ten types of EcPVs have already been described; however, only EcPVs 1, 3, 4, 5, and 6 have been observed in association with aural plaques. Accordingly, the objective of this study was to evaluate the presence of EcPVs in equine aural plaque samples. A total of 29 aural plaque samples (from 15 horses) were collected and assessed for the presence of the DNA of these EcPVs by PCR. Additionally, 108 aural plaque samples used in previous research were evaluated for the presence of EcPVs 8 and 9. Previously described primers we...
Clayton HM, Duncan JL.From June to October 1978 four pony mares and foals and two donkey mares and foals grazed a paddock contaminated with Dictyocaulus arnfieldi larvae. No signs of respiratory disease were seen in the foals but within 11 weeks of exposure to the paddock all six developed patent lungworm infections. In October 1978 one donkey and two pony foals were killed. At post mortem examination parasites in various stages of development and measuring up to 8 cm in length were found in the lungs. At this time the three surviving foals were stabled for the remainder of the experiment. Two of these ceased passi...