Infections in horses encompass a range of diseases caused by various pathogens, including bacteria, viruses, fungi, and parasites. These infections can affect different systems within the horse, such as the respiratory, gastrointestinal, and integumentary systems, leading to a variety of clinical signs depending on the pathogen and the severity of the infection. Common infectious diseases in horses include equine influenza, strangles, and equine herpesvirus. Diagnosis often involves clinical examination, laboratory testing, and sometimes imaging, to identify the causative agent and assess the extent of the disease. Treatment strategies may include antimicrobial therapy, supportive care, and preventive measures such as vaccination and biosecurity practices. This page aggregates peer-reviewed research studies and scholarly articles that explore the pathogenesis, diagnosis, treatment, and prevention of infectious diseases in equine populations.
Gay CC, Lording PM.Actinobacillus equuli was the cause of peritonitis in 5 horses. In 3 the onset was sudden with intestinal stasis and acute abdominal pain as predominant findings. Two others presented with chronic disease and weight loss. Characteristically the peritoneal fluid had a high nucleated cell count with non-degenerate neutrophils as the predominant cell type. Four horses were treated and recovered.
Perryman LE, Torbeck RL.A 3-year prospective breeding trial was designed to verify the mode of inheritance of combined immunodeficiency (CID) in Arabian horses. Twenty-six mares that had previously produced foals with CID were mated to a stallion that had sired foals with CID. Of 53 foals obtained, 15 (28.3%) had CID. The ratio of female to male foals was 28:25, and the ratio of female CID to male CID foals was 8:7. The results of this trial confirmed a suggestion that CID in Arabian horses is inherited as an autosomal recessive trait.
Tinling SP, Cardinet GH, Blythe LL, Cohen M, Vonderfecht SL.The structure of sarcocysts in a horse is presented. Light microscopic examination revealed that the maximum cyst dimensions were 136 X 990 micrometers and the cyst walls were striated and 1 to 3 micrometers thick. Electron microscopic examination revealed that the "cyst wall" was formed by villuslike protrusions of the parasitophorous vacuole's primary wall. A unique feature was the presence and arrangement of microtubules within the parasitophorous vacuole. Thirty-four to 55 microtubules extended from the apical tips and sides of each villus and passed through the ground matrix to form junct...
Merritt AM, Smith DA.The concentrations of acetate (C2), propionate (C3), isobutyrate (iC4), butyrate (nC4), isovalerate (iC5), and valerate (nC5) were measured in the feces of 16 clinically normal horses and 44 horses with chronic diarrhea of at least 1-month's duration. The diarrheal horses were categorized diagnostically as: (1) no discernible clinical abnormalities other than diarrhea and in some cases, weight loss (open); (2) clinical evidence of strongyle larval migrans; and (3) Salmonella organisms recovered from the feces. Osmolarity of the feces of 14 of the normal and 15 of the sick horses also was measu...
McGowan JJ, Allen GP, Barnett JM, Gentry GA.Infection of horse KyED cells with equine herpesvirus type 3 (EHV-3) resulted in a sevenfold increase in cytosol deoxythymidine kinase (dTK) activity. The EHV-3 dTK was purified from KyED cytosol dTK by affinity chromatography on deoxythymidine-Sepharose and characterized with respect to its electrophoretic mobility, molecular weight, substrate specificity, phosphate donor specificity, and immunological specificity. The purified EHV-3 dTK migrated in polyacrylamide gels with an Rf of 0.30 and sedimented in glycerol gradients with an S value of 5.13, corresponding to a molecular weight of 83,00...
Fernie DS, Batty I, Walker PD, Platt H, Mackintosh ME, Simpson DJ.The vaccination of four ponies on two occasions with a formolised culture of Haemophilus equigenitalis produced a high circulating antibody titre to the organism in each pony. Three out of four vaccinated and all of three unvaccinated ponies developed typical symptoms of contagious equine metritis (CEM) when subsequently challenged with a vaginal exudate containing H equigenitalis. Similarly, three ponies which had previously been infected with H equigenitalis and which had recovered spontaneously also developed contagious equine metritis when rechallenged with the organism. The clinical and b...
Miller R, Pott B.A case of subcutaneous phycomycosis of a horse from which Basidiobolus haptosporu was isolated is described. Although some clinical signs were similar to the disease caused by Hyphomyces destruens, the gross and microscopic pathology were different in several respects. Main characteristics of the histopathology were the narrow eosinophilic sleeve around wide, frequently septate hyphae scattered throughout the affected tissue and found commonly at the advancing border of the lesion. A retrospective study of 63 cases of phycomycosis diagnosed at this laboratory since 1970 indicated a further 11 ...
Scott DW, Wolfe MJ, Smith CA, Lewis RM.In a review of non-viral bullous skin diseases of domestic animals and a 4-year study of cases presented to the New York State College of Veterinary Medicine, we found 15 diseases: pemphigus vulgaris, pemphigus vegetans, pemphigus foliaceus, pemphigus erythematosus, bullous pemphigoid, systemic lupus erythematosus, dermatitis herpetiformis, toxic epidermal necrolysis, drug eruption, epidermolysis bullosa, epidermolysis bullosa simplex, familial acantholysis, bovine congenital porphyria, impetigo and subcorneal pustular dermatosis. The 15 diseases were placed in five categories: autoimmune, imm...
Makinde AA.The reverse single radial immunodiffusion technique was used to detect Dermatophilus congolensis antibody in sera collected from animals previously infected to varying levels with D congolensis. Ammonium sulphate and trichloroacetic acid extracts of five different strains of D congolensis obtained from different geographical locations were used as antigens. All the extracts showed variations in their sensitivities in detecting D congolensis antibody in the various serum samples. Multiple antibodies were detected by some extracts while some showed negative antibody reaction to all extracts. Two...
Gibbons DF.Salmonellosis in Equidae occurs sporadically throughout the world; the incidence recorded ranges from less than 1 per cent to as much as 27 per cent. In 1976 there was a significant increase in disease and mortality caused by salmonellosis in horses in Britain and treatment was less successful than with other species. Data revealed a general progressive shift away from species specific salmonella serotypes towards the ubiquitous but less discerning strains of Salmonella typhimurium. The role of predisposing causes is assessed and treatment, prevention and zoonitic importance commented upon.
Duncan JL, McBeath DG, Preston NK.The efficacy of a fenbendazole divided dose regime against immature stages of Trichonema spp, Strongylus vulgaris and Strongylus edentatus was evaluated. A group of 8 naturally infected 30 to 36-month-old ponies was divided into 2 equal groups on the basis of previous treatment and faecal egg counts, one group being treated with 7.5 mg/kg bwt of fenbendazole daily for 5 days. This treatment regime removed 80 per cent of migrating S vulgaris larvae, 100 per cent of migrating S edentatus larvae and 95 per cent of the mucosal stages of Trichonema spp. In addition, a virtual 100 per cent eliminati...
Urch DL, Allen WR.The efficacy of orally administered fenbendazole on lung and intestinal parasitism in equids was investigated in a mixed herd of pony mares, jenny donkeys and foals. A single dose of 7.5 mg fenbendazole/kg body weight effectively removed intestinal parasites from the ponies, donkeys and foals, but higher doses and repeated treatments failed to eliminate lungworm infections in donkeys. The finding of eosinophilia proved useful in detecting lungworm infections in donkeys.
Willeberg P, Ruppanner R, Behymer DE, Haghighi S, Kaneko JJ, Franti CE.The prevalence of agglutinating serum antibodies against Coxiella burnetii, the cause of Q fever in humans, was tested in a hospital population of companion animals and livestock in California during 1973--1975. A sample of stray dogs was also tested. Among the hospitalized animals 346 (48%) of 724 dogs, 7 (9%) of 80 cats, 9 (32%) of 28 cattle and 31 (26%) of 121 horses had antibodies against C. burnetii. Of 316 stray dogs 208 (66%) were seropositive. The overall prevalence of 53% among 1040 dogs tested was comparable to the 63% antibody prevalence found in an earlier survey among coyotes and ...
England JJ, Reed DE.Negative contrast electron microscopy (NCEM) was utilized as a routine tool in the diagnosis of viral infections of domestic and wild animals. Viruses identified by this technique were observed in infected culture systems or clinical specimens from several species including horses, cattle, sheep, dogs, cats, pigs, deer, Rocky Mountain bighorn sheep, antelope, and several avian species. Viruses were identified by NCEM based on their size, morphology, and symmetry and consisted of adenoviruses, herpesviruses, paramyxoviruses, myxoviruses, picornaviruses, parvoviruses, coronaviruses, reoviruses, ...
Breukink HJ, Németh F, van Dieten JS.The clinical examination, anaesthesia and surgery in a gelding with an incarcerated scrotal hernia are described. The results of examination of the blood at regular intervals are shown in a table. Surgery was performed without enterectomy. The postoperation course was uneventful. It is concluded that the possibility of scrotal hernia should be borne in mind, even in geldings with colic. The incarcerated portion of the small intestine is usually found to be the jejuno-ileal junction. The anaesthesiological and surgical features of equine scrotal hernia are discussed.
McCool CJ, Gilfedder J.This study explores a rare case where an equine disease was found to be caused by Salmonella anatum, an organism typically associated with cattle, in a week-old foal and its […]
Liefman CE.The protection afforded by active, passive and combined active-passive methods of immunisation against tetanus was examined in previously unimmunised horses. Three groups of horses were injected; one with tetanus toxoid alone, one with tetanus antitoxin alone and one in which the tetanus toxoid and tetanus antitoxin were injected simultaneously. The protection afforded was determined by monitoring the levels of antitoxin achieved in the horses by each of these methods. The results obtained demonstrated the effectiveness of the combined active-passive method in affording rapid and prolonged pro...
Timoney PJ.The usefulness of the double immunodiffusion test for the diagnosis of louping ill infection was investigated. Whereas louping ill viral antigen was not detected in brain material from field cases of the infection, its presence was readily confirmed in suckling mouse brain isolates of the virus. The double immunodiffusion test was found to be unreliable as a serological test for the retrospective diagnosis of louping ill infection in the horse.
Wood JL, Kelly L, Cardwell JM, Park AW.The transmission of contagious equine metritis (CEM) on stud farms in Britain, Ireland and other European countries is prevented by following the recommendations in the Horserace Betting Levy Board's Code of Practice on CEM. A quantitative risk assessment was undertaken to estimate the likely impact of removing the recommendation, from the 2002 code, to culture endometrial or cervical swabs microaerophilically for the presence of Taylorella equigenitalis, the causative organism. The scientific literature was reviewed for evidence about the anatomical distribution of T. equigenitalis at differe...
Coignoul FL, Bertram TA, Cheville NF.Three pony mares and 4 pony foals were inoculated with a subtype 2 strain of equine herpesvirus 1. Foals had periods of fever 12 h and 2.5 days after inoculation and leukopenia, involving both neutrophils and lymphocytes, followed by leukocytosis. Mares had transient fever and leukopenia 24 hours after inoculation that were less severe than in foals. An increase in circulating virus-neutralizing antibody was seen in 2 of 3 inoculated mares, but not in foals. Attempts to isolate virus from blood were unsuccessful. These studies show that equine herpesvirus 1 subtype 2 is a mild pathogen for pon...
Norman TE, Chaffin MK, Perris EE, Edwards JF, David JB, Cohen ND, Reuss S.This report involves 6 cases in which medical records and post mortem findings were reviewed leading to the diagnosis of massive pulmonary thromboembolism (MPTE). All horses were mature and MPTE has not been recognised previously as a sequel to generalised systemic illness in mature horses. The clinical data and pathological findings of the cases are reported and the authors conclude that MPTE is an uncommon but important complication of medical and surgical disorders in mature horses. In 3 of the cases, the condition was nonfatal suggesting that some horses having developed PTE survive and th...
Breuhaus BA.To determine whether ingestion of fescue seed infected with the endophyte Neotyphodium coenophialum would alter thyroid function in adult horses. Methods: Original study. Methods: 4 adult mares that were not pregnant and 6 adult geldings. Methods: Thyrotropin releasing hormone stimulation tests were performed while horses received a standard diet and after infected seed (2.3 kg/d [5 lb/d]) had been fed for 1 and 2 months. Serum prolactin concentrations were measured to verify endophyte absorption. Results: Serum prolactin concentrations indicated that at least 8 of 10 horses absorbed the endop...
Smith RD.In this article, I have discussed the principles and methods of outbreak investigation, reinforcing important concepts with examples from the veterinary literature. The approach presented is applicable to outbreaks caused by any agent whether it is infectious versus noninfectious or contagious versus noncontagious. The solutions vary. The experience of others presented with similar situations may be especially helpful. Because of their nature, outbreaks are difficult to prepare for. When faced with a potential outbreak, the best strategy is to approach it scientifically, systematically, and wi...
Egerton JR.Until the latter part of the nineteenth century, there were no domestic animals other than pigs, dogs and poultry in the island of New Guinea. From 1889 onwards, occupying authorities, missionaries and settlers from Germany, the UK, Japan and Australia imported ruminants, pigs and horses. Some of these importations were from Asia. This paper describes some outcomes of those importations and the potential hazards for Australia entailed in them.
Brown AE, Hansen PJ, Asbury AC.Uterine flushings collected from mares before and after bacterial-induced inflammation were assayed for ability to opsonize Streptococcus zooepidemicus for phagocytosis by polymorphonuclear leukocytes. Opsonization was measured as the peak phagocytic rate of bacteria preincubated with uterine flushings relative to the peak phagocytic rate of unopsonized bacteria. Flushings from four mares with noninfected uteri were unable to opsonize bacteria regardless of whether uteri were flushed at estrus or on day 10 postovulation. In a second experiment, 7 X 10(9) live S. zooepidemicus were inoculated i...