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.
Reinecke RK, Loots LJ, Reinecke PM.Dichlorvos in a special slow release formulation at 31 mg/kg body mass in equines was highly effective against all adult strongyles and Oxyuris equi, Parascaris equorum, Probstmayria vivipara and bots of Gasterophilus spp. It has no effect on 4th stage larvae of Trichonema ssp. nor the stomach worms Draschia megastoma and Habronema spp. Doses of dichlorovos 10 and 20 times the therapeutic dose (310 and 620 mg/kg body mass) caused transient clinical signs but these disappeared 96 hours after dosing.
Sheahan BJ, Atkins GJ, Russell RJ, O'Connor JP.Two aged mares with histiolymphocytic lymphosarcoma had multiple rapidly proliferating tumours in the subcutis. Consistent haematological changes were absent. One mare had lymph node involvement but no neoplastic lesions in the viscera. Microbiological examination of tumour tissue showed coryneform bacteria; there was no evidence of C-type or lytic viruses or of reverse transcriptase. Prominent intramitochondrial crystalline inclusions were in histiocytic tumour cells.
Swerczek TW.Four experiments were performed to elucidate the pathogenesis of toxicoinfectious botulism in horses and foals. Groups of horses and foals were inoculated with one of the following: (1) crude toxin of Clostridium botulinum, type B, given IV, (2) C botulinum spores, given IM, (3) C botulinum spores, given IM, in necrotic lesions, and (4) C botulinum spores, given orally with and without dexamethasone. Toxin of C botulinum in minute amounts is toxic to horses. Clostridium botulinum spores produced toxicosis only when necrotic lesions were present. When C botulinum spores were given orally, they ...
Perryman LE, Liu IK.Nine foals with combined immunodeficiency were given hepatic and thymus cells from 68- to 110-day-old (gestational age) fetuses or peripheral blood lymphocytes from nonrelated horses. Clinical signs and lesions consistent with graft vs host reaction were observed in eight of the foals. Diarrhea was observed in these 8 foals, and ulcerative dermatitis, stomatitis, or glossitis was detected in 6 of the 8 foals. Histopathologic changes consisting of necrosis and lymphocyte infiltration were observed in liver, skin, alimentary tract, and less frequently in lymphoid tissues. Changes in complete blo...
Donnelly J, Joyner LP, Graham-Jones O, Ellis CP.The incidence of antibodies to Babesia equi and B. caballi in horses in the Royal Stables of His Majesty the Sultan of Oman was assessed by complement fixation (CF) and immunofluorescent antibody (IFA) tests. Two series of samples taken with a 2-year interval, mainly from animals reared in Oman, indicated a stable but high prevalence of antibodies. On the 2 occasions 94.6 and 97.7% respectively were positive to B. equi by IFA and 76.8 and 75.0% were positive by CF. For B. caballi the corresponding percentage figures were lower--67.9 and 40.9 by IFA and 30.4 and 40.9 by CF. A group of animals t...
Simpson CF, Neal FC.Four splenectomized ponies were infected with Babesia equi. Two ponies were not treated, and two were treated with 5 mg of imidocarb/kg of body weight when 20% of their erythrocytes were parasitized. The nucleus of the parasite in erythrocytes from blood smears of nontreated ponies was roundish, deep red-staining, and usually composed two-thirds of the organism. The parasite in erythrocytes from blood smears of treated ponies was swollen and vacuolated except for an area just beneath the plasma membrane where the compressed nucleus was marginated, elongated, and clumpy. Parasites in erythrocyt...
Smith BP, Timm K, Jahn S, Reina-Guerra M.Three of 33 ponies died after the herd had been moved to a new environment 3 months earlier. One mare died without premonitory signs of illness. Shortly thereafter, a 5-day-old foal and a 2-year-old gelding died after brief illness. Although cultures were not performed on the mare, Salmonella typhimurium was isolated from the feces and tissues of the foal and gelding. Lesions in the foal were confined to ecchymotic hemorrhages on the mucosal surface of the colon and petechial hemorrhages in the splenic capsule, with adhesions to the parietal peritoneum. The gelding had evidence of severe typhl...
Freeman DE, Donawick WJ.An intravascular procedure was used to occlude the internal carotid artery of two horses with epistaxis caused by guttural pouch mycosis. In each horse, the affected internal carotid artery was ligated close to its origin. A balloon-tipped catheter was introduced into the artery distal to the ligature, and its tip was advanced beyond the site of infection. The balloon was then inflated so that the infected segment of artery was isolated from the cerebral vascular system. The catheters were removed at 14 and 51 days, and both horses were returned to training and racing. Neither horse had furthe...
Swerczek TW.Toxicoinfectious botulism was proved to be the cause of a neuromuscular paralytic syndrome in foals and adult horses. In eight successive cases, Clostridium botulinum type B was isolated at necropsy. Foals were either found dead without premonitory signs of illness or, most often, they had signs of progressive and symmetric motor paralysis. Stilted gait, muscular tremors, and the inability to stand longer than 4 to 5 minutes were the salient clinical signs. Other clinical manifestations included dysphagia, constipation, mydriasis, and frequent urination. As the disease progressed, dyspnea with...
Woolcock JB, Mutimer MD, Farmer AM.Using a selective medium, the epidemiology of Corynebacterium equi in horses was studied. Twelve horse studs in different geographical locations were investigated. In addition, a group of horses was monitored over a period of time to determine whether faecal carriage of C equi is constant or intermittent. It was found that C equi could be recovered from every property tested and from all horse breeds. The organism was found in mares, stallions, yearlings and two year olds, and foals aged from 10 days to several months. It appears that C equi is widespread and that its occurrence is not related...
Dabernat HJ, Tainturier D, Delmas C, Ferney J, Lareng MB.The cultural, biochemical, antigenic and antibiotic susceptibility characteristics of 17 strains of Haemophilus equigenitalis, the causative organism of contagious equine metritis (CEM), were studied. Biochemical characteristics were investigated using both conventional method and the API ZYM system of enzyme detection. The biochemical profile of the H. equigenitalis strains was unique and differed from the other bacterial species studied under the same experimental conditions (H. influenzae and H. parainfluenzae, B. abortus and B. melitensis, P. multocida, A. calcoaceticus). The required X an...
Dietz WH, Galindo P, Johnson KM.In late June 1973, a small outbreak of equine encephalitis caused by eastern equine encephalomyelitis (EEE) virus occurred in the Republic of Panama. At least 100 horses were affected by the disease and 40 died. More than 1,700 human sera were obtained from areas of virus activity but no serological evidence for infection was found. Four isolates of EEE virus were recovered, one of which was from a small pool of Culex taeniopus mosquitoes. Serologic studies of infected horses and classification by the short incubation hemagglutination-inhibition tests revealed that these isolates were South Am...
Clayton HM, Duncan JL, Dargie JD.The mechanisms involved in the pathophysiological disturbances associated with the presence of mature Parascaris equorum in the small intestine were investigated with radioisotopic techniques. The results suggested that, compared with worm-free controls, infected foals had a reduction in gut motility, an increase in the body solids ratio, a lowering of the body pool of albumin and a decreased ability to incorporate dietary methionine into plasma protein.
Turner WH, Pickard DJ.A new haemolysin from Staphylococcus aureus produced opaque zones of haemolysis on horse blood agar but did not lyse equine erythrocytes suspended in phosphate-buffered saline. The haemolysin was not neutralized by normal rabbit serum and was distinct from alpha-, beta- and delta-haemolysins as well as human leucocidin. Partially purified preparations produced erythema when injected intradermally into rabbit skin.
van Veenendaal JC, Speirs VC, Harrison I.A surgical technique of open drainage, using penrose drains and pressure bandages, was used for the treatment of hygromata in four horses. In 3 cases with hygroma of the carpus, one with a secondary infection, there was complete resolution of the condition whereas in the one case with hygroma of the elbow resolution was more protracted because of difficulties in bandaging. The cosmetic and functional results after operation were most satisfactory.
Obuch-Woszczatyński P, Pituch H, Martirosian G, Silva J, Meisel-Mikołajczyk F, Łuczak M.Seven Bacteroides fragilis strains were cultured from samples collected from horses. From all the tested strains, as well as from the reference B. fragilis strains: enterotoxigenic NCTC 11925 and nonenterotoxigenic IPL 323 strain, DNA was isolated using Genomic DNA PREP PLUS isolation kit manufactured by A&A Biotechnology (Poland). To detect the enterotoxin (fragilysin) gene, polymerase chain reaction (PCR) was applied, using the following starters: 404 (GAG CCG AAG ACG GTG TAT GTG ATT TGT) and 407 (TGC TCA GCG CCC AGT ATA TGA CCT AGT). DNA obtained from bacterial cells was amplified in a ...
Belloli C, Badino P, Carcano R, Odore R, Arioli F, Caloni F, Re G.The affinity and functional effects of isoxsuprine enantiomers were investigated to determine the enantiospecificity of the beta-agonistic and alpha-blocking effects. Functional assays on isolated smooth muscle preparations from equine common digital artery were performed to determine the apparent affinity (pD(2)) and intrinsic activity (alpha(E)) of (-)erythro-isoxsuprine (alphaS, betaR, gammaR) and (+)erythro-isoxsuprine (alphaR, betaS, gammaS). The affinity of two enantiomers for the different adrenoceptor types was studied by radioligand binding assays on membrane preparations from the sam...
Lee HF, Lee JD, Lee YC.In course of immunizing horses with snake venoms, tetanus and diphtheria toxoids, a new serum component, T-globulin, was formed and migrated between the beta- and gamma-globulins. The T-globulin content was parallel with the antibody titre after the middle course of immunization. There were many components in snake antivenin and T-globulin was composed of most of those components. The components of diphtheria T-globulin were the same as those of crude antitoxin and tetanus T-globulin except one precipitin.
Alexander GR, Gibson KT.Two mares presented with life-threatening rectal tears were successfully treated with intensive medical management. Although surgery has been regarded as mandatory for grade 3 or 4 rectal tears in the past, recent reports have indicated the value of medical management alone. The case reports presented in this article detail the use of antibiotics, flunixin meglumine, laxative diets and faecal softeners in the medical management of two mares presented with grade 3 rectal tears.