Pyrexia, commonly referred to as fever, is an elevation in body temperature that occurs as a physiological response to various stimuli, including infection, inflammation, or other underlying medical conditions in horses. It is a common clinical sign observed in equine practice and can indicate the presence of an underlying health issue. The regulation of body temperature is controlled by the hypothalamus, and pyrexia results when this regulatory center adjusts the set point to a higher temperature in response to pyrogens, which can be endogenous or exogenous. Monitoring and assessing pyrexia in horses are important for diagnosing and managing potential health problems. This page compiles peer-reviewed research studies and scholarly articles that explore the causes, mechanisms, and implications of pyrexia in equine health, as well as its role in disease processes and treatment considerations.
Morgan JM, Aceto H, Manzi T, Davidson EJ.Complications are a practical consideration for elective magnetic resonance imaging (MRI) studies performed under general anaesthesia but relatively little is known about their distribution and risk factors. Objective: To describe the incidence of complications associated with MRI performed under general anaesthesia at a large referral facility and evaluate potential risk factors for these complications. Methods: Retrospective case-control study. Methods: Patient information and details of the MRI procedure were collected retrospectively from medical records of all horses that had undergone an...
Osterrieder K, Dorman DC, Burgess BA, Goehring LS, Gross P, Neinast C, Pusterla N, Hussey GS, Lunn DP.Equine herpes virus type 1 (EHV-1) infection in horses is associated with respiratory and neurologic disease, abortion, and neonatal death. Objective: Vaccines decrease the occurrence of clinical disease in EHV-1-infected horses. Methods: A systematic review was performed searching multiple databases to identify relevant studies. Selection criteria were original peer-reviewed research reports that investigated the in vivo use of vaccines for the prevention of disease caused by EHV-1 in domesticated horses. Main outcomes of interest included pyrexia, abortion, neurologic disease, viremia, and n...
Hoblick S, Denagamage TN, Morton AJ, McCarrel TM.Post-anaesthetic fever is a known complication of general anaesthesia, however, its incidence in horses undergoing elective magnetic resonance imaging (MRI) is unknown. Objective: To determine the incidence of post-anaesthetic fever in horses undergoing elective orthopaedic MRI and determine whether prophylactic antimicrobial therapy would be associated with a reduction in the incidence of post-anaesthetic fever. We hypothesised that prophylactic antimicrobials would be associated with a reduction in the incidence of post-anaesthetic fever. Methods: Retrospective cross-sectional study. Methods...
Scala E, van Galen G, Skärlina EM, Durie I.Pyelonephritis is a serious condition that is rarely described in horses. In contrast, urinary tract infections are common in humans and small animals, and multi-drug-resistant urinary infections are an emerging threat. In this report, we describe a horse with unilateral pyelonephritis caused by extended-spectrum beta-lactamase-producing bacteria belonging to the Enterobacter cloacae complex. [Correction added on 9 August 2023, after first online publication: The preceding sentence was corrected.] An 11-year-old Swedish warmblood gelding was diagnosed with a cystolith and a cystotomy through a...
Gold JR, Grubb T, Court MH, Villarino NF.Acetaminophen is utilized in human infants for pain management and fever. Neonatal foals might benefit from administration of acetaminophen but effective and safe dosage regimens for neonatal foals remains to be determined. Unassigned: The objective was to determine the plasma pharmacokinetics of acetaminophen following oral administration of a single dose of 20 mg/kg or 40 mg/kg to neonatal foals. A secondary objective was to evaluate any changes in hematology and biochemistry profiles. Unassigned: Randomized study. Unassigned: Eight clinically healthy 7-9-day old Quarter Horse foals (3 c...
Linn-Peirano SC, Hepworth-Warren K, Kinsella H, Diaz-Campos D, Brenseke BM, Cianciolo RE, Schroeder E, Schreeg ME.Equine ingesta-associated choledocholithiasis is a rare cause of morbidity and mortality. We describe here the clinical, gross, histologic, and microbiologic features of this condition in 2 horses and compare the features to 2 previous cases. Case 1 was a 4-y-old Thoroughbred mare with colic. Case 2 was an 18-y-old American Paint Horse mare with colic, chronic weight loss, and inappropriate mentation. Both had elevated biochemical markers of hepatocellular injury and cholestasis and were euthanized given a poor prognosis. Case 1 had a well-formed 5-cm choledocholith surrounding a piece of hay,...
Dehghan Rahimabadi P, Nazari A, Kamyabi M, Mosavari N.Glanders is the oldest and very contagious disease among horses caused by Burkholderia mallei. The disease occurs as a chronic form in horses. Hence, because of the prolonged shedding, numerous horses can potentially get infected by one horse with glanders. Glanders is endemic in Iran and this causes occasional occurrence in horse population of the country. The aim of this study was to determine the incidence of B.mallei infection in horses in two central provinces of Iran. A total of 517 serum samples were collected from stable horses in Tehran and Alborz provinces. Among the studied horses, ...
Kang H, Zsoldos RR, Sole-Guitart A, Narayan E, Cawdell-Smith AJ, Gaughan JB.Healthy adult horses can balance accumulation and dissipation of body heat to maintain their body temperature between 37.5 and 38.5 °C, when they are in their thermoneutral zone (5 to 25 °C). However, under some circumstances, such as following strenuous exercise under hot, or hot and humid conditions, the accumulation of body heat exceeds dissipation and horses can suffer from heat stress. Prolonged or severe heat stress can lead to anhidrosis, heat stroke, or brain damage in the horse. To ameliorate the negative effects of high heat load in the body, early detection of heat stress and im...
Mercer MA, Davis JL, McKenzie HC, Messenger KM, Schaefer E, Council-Troche RM, Werre SR.Acetaminophen has been evaluated in horses for treatment of musculoskeletal pain but not as an antipyretic. Objective: To determine the pharmacokinetics and efficacy of acetaminophen compared to placebo and flunixin meglumine in adult horses with experimentally induced endotoxemia. Methods: Eight university owned research horses with experimentally induced endotoxemia. Methods: Randomized placebo controlled crossover study. Horses were treated with acetaminophen (30 mg/kg PO; APAP), flunixin meglumine (1.1 mg/kg, PO; FLU), and placebo (PO; PLAC) 2 hours after administration of LPS. Plasma ...
Acevedo HD, Hassebroek AM, Leventhal HR, Duhamel GE, Carvallo FR.A 17-y-old Rocky Mountain gelding was presented to the Virginia-Maryland Veterinary Teaching Hospital because of a 4-wk history of anorexia, weight loss, lethargy, and fever of unknown origin. Abdominal ultrasound revealed lymphadenomegaly of the abdominal and colonic lymph nodes, thickening of the wall of the large colon, and a mass associated with the large colon. The horse was euthanized given a poor prognosis. On autopsy, an ~20-cm diameter mass was found within the mesocolon between the right ventral and right dorsal colon. The mass had invaded through the colonic walls and formed a fistu...
Oliver A, Conrado FO, Nolen-Walston R.Equine granulocytic anaplasmosis is a clinically significant and common disease of equids that has a broader prevalence than was once thought. The most common clinical signs include high fever and edema, with mild to mderate thrombocytopenia and lymphopenia typically noted on complete blood count. Subclinical cases are reported and many are self-limiting. Rare clinical presentations include neurologic disease, vasculitis, dysphagia, rhabdomyolysis, or bicavitary effusion. Most cases resolve rapidly with appropriate antimicrobial intervention.
Taylor SD.Potomac horse fever (PHF) is a common cause of equine colitis in endemic areas. Until recently, the only causative agent known to cause PHF was Neorickettsia risticii. However, N. findlayensis has been isolated from affected horses. Horses typically become infected upon ingestion of Neorickettsia spp.-infected trematodes within aquatic insects. The most common clinical signs include diarrhea, fever, anorexia, lethargy and colic. The diagnostic test of choice for PHF is PCR of blood and feces. Tetracyclines remain an effective treatment. Supportive care, including fluid therapy, colloid ad...
Jaramillo-Morales C, James K, Barnum S, Vaala W, Chappell DE, Schneider C, Craig B, Bain F, Barnett DC, Gaughan E, Pusterla N.This study aimed to describe selected epidemiological aspects of horses with acute onset of fever and respiratory signs testing qPCR-positive for and to determine the effect of vaccination against on qPCR status. Horses with acute onset of fever and respiratory signs from all regions of the United States were included in a voluntary biosurveillance program from 2008 to 2020 and nasal secretions were tested via qPCR for and common respiratory viruses. A total of 715/9409 equids (7.6%) tested qPCR-positive for , with 226 horses showing coinfections with EIV, EHV-1, EHV-4, and ERBV. The median...
Gold JR, Grubb T, Court M, Villarino NF.Acetaminophen is a common analgesic and antipyretic drug used in human medicine and might be an alternative to nonsteroidal anti-inflammatory drugs for treating pain and pyrexia in foals. The pharmacokinetics and safety of differing doses of acetaminophen have not been investigated in foals. Objective: To determine the plasma pharmacokinetics and any changes in haematology and biochemistry profiles following oral administration of single doses of acetaminophen at 10, 20, and 40 mg/kg to foals. Methods: Randomised cross-over pharmacokinetic study. Methods: Six Quarter Horse (two colts and fou...
Lohmann KL, Sieg M, Landmann M, Ganzenberg S, Arnold C, Vahlenkamp T, Ulrich RG.The presenting complaints, clinical signs, diagnostic evaluation, therapy, and outcome of 12 horses with clinically apparent West-Nile-Virus (WNV) infection are described. Methods: Case series RESULTS: The adult horses (age 6-18 years, 7 mares, 5 geldings) from Saxony and Saxony-Anhalt were presented with various clinical histories between September 2018 and September 2020. All horses were presented in August or September and no horse was vaccinated against WNV. Fever as the most common general clinical sign was present in 8/12 horses. The most common neurological signs were muscle fascicula...
Pusterla N.Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In equids, equine coronavirus has been associated with diarrhea in foals and lethargy, fever, anorexia, and occasional gastrointestinal signs in adult horses. Although horses seem to be susceptible to the human severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) based on the high homology to the ACE-2 receptor, they seem to be incidental hosts because of occasional SARS-CoV-2 spillover from humans. However, until more clinical and seroepidemiological data are available, it remains important to m...
Fouché N, Remy-Wohlfender F, Blau D, Franzen J, Gurtner C, Seuberlich T, Unger L, Gerber V.Outbreaks of equine coronavirus (ECoV) infections have been described in different parts of the world including Europe. The aim of this report was to describe clinical signs, diagnostic work-up and outcome of the first documented outbreak of ECoV in Switzerland in order to raise the awareness for the disease and its various clinical presentations. The outbreak occurred on a farm with 26 horses. Of these, seven horses developed clinical disease ranging from mild signs such as fever and anorexia to severe signs of acute colitis. One horse died due to severe endotoxemia and circulatory shock seco...
Ohta M, Kambayashi Y, Mita H, Kuroda T, Bannai H, Tsujimura K, Yamanaka T, Garvey M, Cullinane A, Yamayoshi S, Kawaoka Y, Nemoto M.Updating vaccine strains is essential to control equine influenza. We evaluated the protective efficacy of an inactivated equine influenza vaccine derived from viruses generated by reverse genetics (RG) in horses in an experimental viral challenge study. Wild-type (WT) virus (A/equine/Tipperary/1/2019) and virus generated by RG (consisting of hemagglutinin and neuraminidase genes from A/equine/Tipperary/1/2019 and six other genes from high-growth A/Puerto Rico/8/34) were inactivated by formalin for vaccine use. Twelve 1-year-old naïve horses with no antibodies against equine influenza virus w...
Fourie I, Snyman J, Williams J, Ismail A, Jansen van Vuren P, Venter M.Although Old World alphaviruses, Middelburg- (MIDV) and Sindbis virus (SINV), have previously been detected in horses and wildlife with neurologic disease in South Africa, the pathogenesis and clinical presentation of MIDV and SINV infections in animals are not well documented. Clinical samples from horses across South Africa with acute or fatal neurologic and febrile infections submitted between 2014-2018 were investigated. In total, 69/1084 (6.36%) and 11/1084 (1.01%) horses tested positive for MIDV and SINV, respectively, by real-time reverse transcription (RT) PCR. Main signs/outcomes for ...
Kambayashi Y, Nemoto M, Tsujimura K, Ohta M, Bannai H.Equine coronavirus (ECoV) causes fever, lethargy, anorexia and gastrointestinal signs in horses. There has been limited information about the prevalence and seasonality of ECoV among Thoroughbreds in Japan. Objective: To understand the epidemiology and to evaluate the potential risk of ECoV infection to the horse industry in Japan. Methods: Longitudinal. Methods: The virus-neutralisation (VN) test was performed using sera collected three times a year at 4 months intervals from 161 yearlings and at 6-7 months intervals from 181 active racehorses in Japan in 2017-2018, 2018-2019 and 2019-2020....
Moolla N, Adler D, Blumberg L, Glass A, Grobbelaar A, Le Roux C, Paweska J, Weyer J.Haemorrhagic fever with renal syndrome (HFRS) is caused by hantavirus infection. Hantaviruses are not endemic to South Africa, and we report the first detection of an imported case of HFRS in the country. The case involved a traveller from Croatia who presented to a Johannesburg hospital with an acute febrile illness with renal dysfunction. The patient reported visiting rurally located horse stables in Croatia before falling ill, and that a worker in the stables with similar illness was diagnosed with HFRS. Given the exposure history and clinical findings of the case, a clinical diagnosis of H...
Straticò P, Razzuoli E, Hattab J, Guerri G, Celani G, Palozzo A, Bonanni D, Fruscione F, Varasano V, Petrizzi L, Marruchella G.A 7-year-old Friesian stallion with a history of oesophageal stenosis, weight loss, inappetence, and recurrent hyperthermia was referred for gastroscopy. The stomach mucosa surrounding the oesophageal opening showed a large, necrotic, and ulcerated mass. On post-mortem examination, a very large, cauliflower-like neoplasm was seen, affecting non-glandular gastric mucosa. Nodular lesions were observed, scattered on the omentum, the spleen, and the liver. Microscopic findings allowed the diagnosis of gastric squamous cell carcinoma with abdominal metastasis. Biomolecular investigations demonstrat...
Pusterla N, James K, Barnum S, Bain F, Barnett DC, Chappell D, Gaughan E, Craig B, Schneider C, Vaala W.A voluntary biosurveillance program was established in 2008 in order to determine the shedding frequency and prevalence factors for common respiratory pathogens associated with acute onset of fever and/or respiratory signs in equids from the USA. Over a period of 13 years, a total of 10,296 equids were enrolled in the program and nasal secretions were analyzed for the qPCR detection of equine influenza virus (EIV), equine herpesvirus-1 (EHV-1), EHV-4, equine rhinitis A and B virus (ERVs), and subspecies (). Single infections with respiratory pathogens were detected in 21.1% of the submission...
Budachetri K, Lin M, Yan Q, Chien RC, Hostnik LD, Haanen G, Leclère M, Waybright W, Baird JD, Arroyo LG, Rikihisa Y.Potomac horse fever (PHF) is an acute and potentially fatal enterotyphlocolitis of horses with clinical signs that include anorexia, fever, diarrhea, and laminitis. Its incidence is increasing despite a commercially available vaccine. PHF is caused by Neorickettsia risticii, and the recently rediscovered and classified . PHF diagnosis is currently accomplished using serology or nested PCR. However, both methods cannot distinguish the two species that cause PHF. Further, the current real-time PCR test fails to detect Thus, in this study, two species-specific real-time PCR assays based on a...
Orellana-Guerrero D, Dini P, Santos E, de la Fuente A, Meyers S, Koshak S, Dujovne G.Transvaginal aspiration of oocytes (TVA) is a commonly used clinical procedure to obtain oocytes for in vitro production of embryos in horses. The goal of this study was to evaluate the effect of the TVA procedure on blood and peritoneal parameters, and to investigate the association of these findings with variables such as use of antibiotics, number of ovarian punctures, and length of the procedure. Physical examination was performed and blood and peritoneal fluid were obtained from 14 mares before they underwent TVA and the same parameters were assessed 24 hours after the procedure. On exami...
McGlennon A, Waller A, Verheyen K, Slater J, Grewar J, Aanensen D, Newton R.Previously national surveillance data for monitoring strangles (Streptococcus equi infection) in UK horses was limited. Improved awareness and knowledge of positive diagnoses would permit the optimisation of biosecurity protocols, decreasing the prevalence of strangles. Methods: Seven UK laboratories reported positive strangles diagnoses between 1 January 2015 and 31 December 2019 based on identifying Streptococcus equi via agent detection assays from field-based practitioner-submitted samples. Associated clinical history and animal signalment were collected where provided, and descriptive ana...
Michishita M, Shibata R, Machida Y, Matsumoto M, Ochiai K, Azakami D.A 20-year-old Dutch Warmblood gelding was referred with clinical signs of anorexia, weight loss, intermittent fever, cough, subcutaneous oedema and exercise intolerance. Haematological examination revealed the presence of blast cells, decreased lymphocytes, mild thrombocytopenia and anaemia but no leucocytosis. Serum analyses detected elevated aspartate aminotransferase and gamma-glutamyl transferase activities and triglyceride concentrations. Twenty-two days after the initial visit, the horse died after showing clinical signs of decreased appetite, increased body temperature, tachypnoea and t...
Längerer L.Bernardino P, James K, Barnum S et al. What have we learned from 7 years of equine rhinitis B virus qPCR testing in nasal secretions from horses with respiratory signs. Vet Rec 2021; 188 (10): e26. DAS EQUINE RHINITIS-B-VIRUS (ERBV) HAT EINE HOHE INZIDENZ, IST IN SEINER BEDEUTUNG JEDOCH NUR WENIG ERFORSCHT. EINE INFEKTION MIT DEM ERBV äUßERT SICH IN SYMPTOMEN WIE FIEBER, ANOREXIE, LETHARGIE, NASENAUSFLUSS, HUSTEN, LYMPHADENOPATHIE UND ÖDEMEN DER DISTALEN GLIEDMAßEN. AUßERDEM TRETEN HäUFIG SUBKLINISCHE INFEKTIONEN AUF. DAS ZIEL DIESER STUDIE WAR, DIE HäUFIGKEIT DES NACHWEISES VON ERBV IM...
Trachsel DS, Drozdzewska K, Bergmann F, Ziegler U, Gehlen H.West Nile virus (WNV) is a mosquito-borne viral pathogen of global importance and is considered to be the most widespread flavivirus. In Germany, first infections with WNV were detected in 2018 and it is expected for these to become more frequent in consequence to warmer winters followed by a rainy/humid springtime. WNV is maintained in an enzootic cycle between ornithophilic mosquitoes and certain wild bird species. Humans and horses are so-called "dead-end hosts" of a WNV infection. They frequently do not fall ill, however occasionally develop overt infections ranging from mild febrile sympt...
Leventhal HR, Hassebroek AM, Carvallo F, McKenzie HC.A 14-y-old pony mare was referred after 30-d duration of intermittent pyrexia, anorexia, weight loss, and change in manure consistency. Physical examination revealed a palpable but reducible ventral abdominal mass. Transabdominal ultrasonography revealed multiple distended, hypomotile, and thickened small intestinal loops in close approximation with numerous, well-defined, hyperechoic masses. There was a large amount of echogenic peritoneal fluid; abdominocentesis revealed a neutrophilic and macrophagic inflammatory exudate, and a mixed bacterial population was cultured. Given the poor prognos...
Pusterla N, Vin R, Leutenegger CM, Mittel LD, Divers TJ.A new enteric virus of adult horses, equine coronavirus (ECoV), has recently been recognized. It is associated with fever, lethargy, anorexia, and less frequently, colic and diarrhea. This enteric virus is transmitted via the feco-oral route and horses become infected by ingesting fecally contaminated feed and water. Various outbreaks have been reported since 2010 from Japan, Europe and the USA. While the clinical signs are fairly non-specific, lymphopenia and neutropenia are often seen. Specific diagnosis is made by the detection of ECoV in feces by either quantitative real-time PCR, electron...
Fukunaga Y, Kumanomido T, Kamada M.Getah virus is a member of the genus Alphavirus in the family Togaviridae and has been frequently isolated from mosquitoes. Seroepizootiologic studies indicate that the virus is mosquito-borne and widespread, ranging from Eurasia to southeast and far eastern Asia, the Pacific islands, and Australasia. The natural host animal of the virus was not known until the first recognized occurrence of Getah virus infection among racehorses in two training centers in Japan in 1978. Outbreaks of clinical disease due to Getah virus infection occur infrequently, and only one outbreak has been reported outsi...
Oue Y, Morita Y, Kondo T, Nemoto M.Equine coronavirus (ECoV) outbreaks have occurred three times at Obihiro Racecourse in Hokkaido, Japan. The third ECoV outbreak occurred between late February and early April 2012. The main clinical signs of affected horses were anorexia, pyrexia and leucopenia; gastrointestinal disease was observed in about 10% of affected horses. Two ECoV strains were isolated from diarrheal samples. All paired sera (9/9) collected from febrile horses showed seroconversion by neutralization test. Sequence and phylogenetic analysis of the ECoV isolated showed that putative amino acid sequences in S and N gene...
Burrell MH, Wood JL, Whitwell KE, Chanter N, Mackintosh ME, Mumford JA.A longitudinal study of respiratory disease in racehorses was carried out to assess its relative associations with different infectious agents and to examine any role that the environmental conditions might play. The relationships between coughing, nasal discharge, pyrexia and lower respiratory tract disease were also examined to provide information for improving clinical diagnosis, particularly of disease of the lower respiratory tract. Lower airway disease was closely associated with infection with Streptococcus zooepidemicus. It was also found that equine herpesvirus seroconversions and S p...
Padalino B, Hall E, Raidal S, Celi P, Knight P, Jeffcott L, Muscatello G.Equine transportation is associated with a variety of serious health disorders causing economic losses. However; statistics on horse transport are limited and epidemiological data on transport related diseases are available only for horses transported to abattoirs for slaughter. This study analysed reports of transport related health problems identified by drivers and horse owners for 180 journeys of an Australian horse transport company transporting horses between Perth and Sydney (~4000 km) in 2013-2015. Records showed that 97.2% (1604/1650) of the horses arrived at their destination with no...
Orrego A, Issel CJ, Montelaro RC, Adams WV.Five serial passages of a cell-adapted strain of equine infectious anemia (EIA) virus were conducted in Shetland ponies. The 13 recipient ponies became agar-gel immunodiffusion test-positive by 25 days after they were inoculated. The virulence of the cell-adapted strain of EIA virus markedly increased through 3 serial passages, although individual variation within passages was high. The 1st serial-passage recipient remained afebrile through 200 days, whereas a febrile episode occurred about every 185, 44, 35, and 33 days in the 2nd, 3rd, 4th, and 5th serial-passage recipients, respectively. Se...
Mumford JA, Hannant D, Jessett DM.Infection of seronegative Welsh mountain ponies was established by intranasal instillation or exposure to nebulised aerosol of egg grown H3N8 viruses. Pyrexia and coughing were noted following intranasal instillation and high titres of virus were recovered from the nasopharynx. Exposure to aerosol resulted in more severe clinical signs characterised by high temperatures, dyspnoea, anorexia and coughing; lower levels of virus were recovered from the nasopharynx. The severity of clinical signs and the kinetics of virus shedding were dose-related with the minimal infectious dose being 10(2)EID50/...
Duncan JL, Pirie HM.The clinical signs, pathology and clinical pathology associated with single experimental infections of Strongylus vulgaris in worm-free pony foals are described. The major clinical signs which became apparent in the infected foals during the first three weeks were pyrexia, anorexia, dullness and abdominal pain. Within the first two weeks of infection lesions were confined to the intestine and terminal branches of the intestinal arteries and consisted of mucosal, submucosal and serosal haemorrhage together with arteritis of submucosal and serosal arteries and also a marked inflammatory reaction...
Maxwell LK, Bentz BG, Gilliam LL, Ritchey JW, Pusterla N, Eberle R, Holbrook TC, McFarlane D, Rezabek GB, Meinkoth J, Whitfield C, Goad CL, Allen GP.OBJECTIVE To determine whether prophylactic administration of valacyclovir hydrochloride versus initiation of treatment at the onset of fever would differentially protect horses from viral replication and clinical disease attributable to equine herpesvirus type-1 (EHV-1) infection. ANIMALS 18 aged mares. PROCEDURES Horses were randomly assigned to receive an oral placebo (control), treatment at detection of fever, or prophylactic treatment (initiated 1 day prior to viral challenge) and then inoculated intranasally with a neuropathogenic strain of EHV-1. Placebo or valacyclovir was administered...
Pusterla N, Huder JB, Feige K, Lutz H.This case report describes a 12-year-old Arabian mare with granulocytic ehrlichiosis. Clinical signs included fever, apathy, anorexia, icterus, limb edema, and reluctance to move. Examination of buffy coat smears revealed Ehrlichia organisms in neutrophils and eosinophils. A band of 1,428 bp was amplified from DNA of leukocytes via nested PCR and was identified as part of the Ehrlichia 16S rRNA gene. It differed from the gene sequences of Ehrlichia phagocytophila and E. equi at two and three positions, respectively. Interestingly, the nucleotide sequence of the 16S rRNA was 100% identical to t...
Giguère S, Jacks S, Roberts GD, Hernandez J, Long MT, Ellis C.The objective of this retrospective study was to compare the efficacy of azithromycin-rifampin, clarithromycin-rifampin, and erythromycin-rifampin for the treatment of pneumonia caused by Rhodococcus equi in foals. Eighty-one foals with naturally acquired pneumonia caused by R. equi were included in the study. Information on age, sex, breed, physical examination findings, laboratory testing, and thoracic radiography was abstracted from each medical record. Foals were divided in 3 groups based on the antimicrobial agent selected for therapy. Short-term (discharge from the hospital) and long-ter...
Madigan JE.Equine ehrlichiosis is a seasonal disease of horses first reported in 1969. Clinical signs in horses include high fever, depression, partial hypophagia, anorexia, limb edema, petechiation, icterus, ataxia, and reluctance to move. Hematologic changes include leukopenia, thrombocytopenia, icterus, anemia, and inclusion bodies, principally in neutrophils and occasionally in eosinophils. Diagnosis is made by clinical signs and observing characteristic morulae in a blood smear with standard Wright's stain. Mortality is low unless secondary infection develops or injury occurs as a result of incoordi...
Burrows R, Goodridge D, Denyer MS.Vaccinated yearlings , two-year-old and in-foal pony mares with appropriate controls were exposed to aerosols of a subtype 1 virus one to two months after two or three vaccinations; all became infected. No obvious differences in the febrile responses, clinical signs and subsequent abortions were found between vaccinated and control mares. All vaccinated yearlings and two-year-old ponies developed a febrile respiratory disease but this was less severe than that suffered by the controls and the amounts and duration of virus shedding were reduced.
Freeman KD, Southwood LL, Lane J, Lindborg S, Aceto HW.Infections are common complications in post operative colic patients. It is the impression of some surgeons that pyrexia in the early post operative period is a sign of infection and appropriate timing of perioperative antimicrobials will decrease the incidence of post operative infection. Objective: To determine the association between 1) post operative pyrexia and development of infection and 2) perioperative antimicrobial drug use and infection rate in post operative colic patients. Methods: Medical records of patients undergoing surgical treatment for colic were reviewed. Horses recovering...
Ito M, Nagai M, Hayakawa Y, Komae H, Murakami N, Yotsuya S, Asakura S, Sakoda Y, Kida H.In August 2007, an outbreak of equine influenza occurred among vaccinated racehorses with Japanese commercial equine influenza vaccine at Kanazawa Racecourse in Ishikawa prefecture in Japan. Apparent symptoms were pyrexia (38.2-41.0 degrees C) and nasal discharge with or without coughing, although approximately half of the infected horses were subclinical. All horses had been shot with a vaccine that contained two inactivated H3N8 influenza virus strains [A/equine/La Plata/93 (La Plata/93) of American lineage and A/equine/Avesta/93 (Avesta/93) of European lineage] and an H7N7 strain (A/equine/...
Dutta SK, Penney BE, Myrup AC, Robl MG, Rice RM.Fifty-five horses were inoculated IV and/or SC with materials containing Ehrlichia risticii, ie, infected whole blood, buffy coat cells, or cell culture, to study clinical and hematologic features of equine monocytic ehrlichiosis (Potomac horse fever). Major clinical and hematologic features of induced E risticii infection were biphasic increase in rectal temperature with peak increases of 38.9 C and 39.3 C on postinoculation days (PID) 5 and 12, respectively; depression; anorexia; decreased WBC count (maximal decrease of 47% on PID 12); and diarrhea from PID 14 to PID 18. Increased WBC count ...
Mumford JA, Jessett DM, Rollinson EA, Hannant D, Draper ME.Seven previously untreated five-month-old New Forest ponies received two doses of equine influenza immunostimulating complex vaccines, one with and one without an immunopurified tetanus toxoid component, given by deep intramuscular injection six weeks apart, followed by a booster dose without tetanus toxoid five months later. Fifteen months after the third dose of vaccine, the ponies were challenged by exposure to an aerosol of influenza A/Equine 2/Sussex/89 (H3N8), a virus isolated from a recent outbreak of influenza A/equine 2 in Britain. The challenge produced severe clinical signs of influ...
Pusterla N, James K, Barnum S, Bain F, Barnett DC, Chappell D, Gaughan E, Craig B, Schneider C, Vaala W.A voluntary biosurveillance program was established in 2008 in order to determine the shedding frequency and prevalence factors for common respiratory pathogens associated with acute onset of fever and/or respiratory signs in equids from the USA. Over a period of 13 years, a total of 10,296 equids were enrolled in the program and nasal secretions were analyzed for the qPCR detection of equine influenza virus (EIV), equine herpesvirus-1 (EHV-1), EHV-4, equine rhinitis A and B virus (ERVs), and subspecies (). Single infections with respiratory pathogens were detected in 21.1% of the submission...
Walton TE, Alvarez O, Buckwalter RM, Johnson KM.Ten horses (Equus caballus) were vaccinated with strain TC-83 Venezuelan equine encephalomyelitis (VEE) virus vaccine. Febrile responses and leukopenia due to a reduction of lymphocytes and neutrophils were observed in all animals. Viremias were demonstrable in eight horses, with a maximum of 10(3.5) median tissue culture infectious dose units per ml of serum in two horses. Clinical illness with depression and anorexia were observed in five horses. Neutralizing (N), hemagglutination-inhibiting, and complement-fixing antibodies to the vaccine virus were demonstrable by 5, 6.5, and 7 days, respe...
Kang H, Zsoldos RR, Sole-Guitart A, Narayan E, Cawdell-Smith AJ, Gaughan JB.Healthy adult horses can balance accumulation and dissipation of body heat to maintain their body temperature between 37.5 and 38.5 °C, when they are in their thermoneutral zone (5 to 25 °C). However, under some circumstances, such as following strenuous exercise under hot, or hot and humid conditions, the accumulation of body heat exceeds dissipation and horses can suffer from heat stress. Prolonged or severe heat stress can lead to anhidrosis, heat stroke, or brain damage in the horse. To ameliorate the negative effects of high heat load in the body, early detection of heat stress and im...
Hailat NQ, Lafi SQ, al-Darraji AM, al-Ani FK.Clinical, haematological and pathological studies were undertaken in Jordan in a stud of 103 racing horses clinically suffering from babesiosis and apparently healthy animals. Out of 47 horses which participated in strenuous exercise, three mares showed sudden onset of immobility and reluctance to move and two mares died. Clinical examination revealed that these five horses (group 1) had fever, anorexia, weakness and severe icterus and, in two mares, haemoglobinuria. Haematological examination revealed that all five horses were heavily parasitized with Babesia equi. This was also found in four...
Matsumura T, O'Callaghan DJ, Kondo T, Kamada M.The virulence of the cell culture adapted KyA strain of equine herpesvirus type 1 (EHV-1), which lacks at least six genes by deletions in its genome, was assessed by intranasal inoculation of six young horses that were serologically negative for EHV-1. No horses showed clinical signs, and a neutralizing antibody response against EHV-1 was detected in two horses which had antibodies against EHV-4 prior to the inoculation. A challenge experiment using a highly virulent strain of EHV-1 conducted 4 weeks later against 4 of the 6 horses inoculated intranasally with the KyA strain and 2 control hors...
Oikawa M, Takagi S, Anzai R, Yoshikawa H, Yoshikawa T.Eight young thoroughbred horses, taken 1858 km by road (travelling time, 41 h), were examined to assess the pathological nature of respiratory disease associated with transport. Three of the horses showed clinical abnormalities including pyrexia, coughing, leucocytosis and neutrophilia after the first 20 h of transportation. Endoscopical examination of the trachea revealed exacerbation of airway inflammation as a result of transport in two of the three affected horses. A consistent finding in the affected horses was focal serous neutrophilic pneumonia affecting the cranio-ventral portion of th...
Yamanaka T, Tsujimura K, Kondo T, Yasuda W, Okada A, Noda K, Okumura T, Matsumura T.Japanese encephalitis (JE) developed in an unvaccinated half-bred horse kept in Tottori Prefecture, Japan. The animal showed ataxia with pyrexia and low appetite, and ultimately died. A viral strain was isolated from the cerebrum of the horse and was identified as JE virus (JEV) by RT-PCR using JEV specific primers. The isolated JEV was classified into genotype I by nucleotide sequence analysis of the viral envelope gene. We believe that this is the first report of the genotype I strain being isolated from a horse.
Lyons ET, Drudge JH, Tolliver SC.Over the past few years, cyathostomiasis has become increasingly recognized as a clinical problem of horses in the United States. Clinical cyathostomiasis has been reported frequently in Europe for a considerable time. This clinical syndrome is usually related to the sudden release of large numbers of the larval stages of small strongyles from the mucosa of the large intestine. Typical clinical signs include diarrhea, ventral abdominal edema, pyrexia, colic, weight loss, and poor body condition. Hypoalbuminemia and the presence of large numbers of small strongyles being passed in the feces are...
Taniguchi A, Fukushi H, Matsumura T, Yanai T, Masegi T, Hirai K.Pathogenicity of equine herpesvirus 9 (EHV-9), a new type of equine herpesvirus isolated from Gazella thomsoni, in horses was investigated by intranasal inoculation of EHV-9 (10(7) pfu) to two conventionally reared 8-months old half-bred weanling horses. Fever higher than 39 degrees C was recorded. Virus was recovered from nasal swabs and peripheral blood mononuclear cells. Both horses developed neutralizing antibody to EHV-9. Perivascular infiltration of mononuclear cells and glial reaction were found in the olfactory and limbic systems. The results suggested that EHV-9 has a pathogenicity in...
McCollum WH, Little TV, Timoney PJ, Swerczek TW.Twelve geldings all became infected when inoculated intranasally with the KY-84 strain of equine arteritis virus (EAV), a strain previously shown to be capable of establishing the carrier state in the stallion. With the exception of one animal that showed no effects other than pyrexia, all of the geldings developed clinical signs characteristic of equine viral arteritis (EVA). The geldings were febrile for varying periods within the range of 2-10 days after inoculation. Viraemia occurred from day 2 onwards, for periods varying from 9 to at least 19 days. Nasal shedding of virus began 2-4 days ...
Morris DD, Crowe N, Moore JN.Serum tumor necrosis factor (TNF) activity was quantitated in 8 horses given an IV infusion of endotoxin (0.03 micrograms of lipopolysaccharide/kg of body weight, from Escherichia coli 055:B5) in 0.9% NaCl solution over 1 hour. Serum TNF activity was likewise measured in 6 horses given only 0.9% sterile NaCl solution at the same rate. The duration of serum TNF activity was determined, and serum TNF activity was correlated with clinical and laboratory changes during the induced endotoxemia. Horses had no serum TNF activity prior to endotoxin administration, but geometric mean serum TNF activity...
Traub-Dargatz JL, Salman MD, Jones RL.A study was designed to identify epidemiologic factors associated with the development and spread of salmonellae in horses in a veterinary teaching hospital, through a case-control study and a longitudinal follow-up prospective study. In the case-control study, 44 horses shedding salmonellae in feces were compared with 99 control horses not shedding salmonellae in feces; regarding breed, sex, age and initial diagnosis, none of the odds ratios for study factors was significant. The factors found to be associated with fecal shedding of salmonellae in the prospective study included diarrhea at th...
Takai S, Anzai T, Fujita Y, Akita O, Shoda M, Tsubaki S, Wada R.Rhodococcus equi strains of intermediate virulence (IMV) for mice possess a 20kDa protein designated Virulence Associated Protein B (VapB) and a virulence plasmid of 79-100kb, and can be recovered from the submaxillary lymph nodes of pigs. The pathogenicity of such R. equi strains for foals is unknown. In this study, two foals, 42 and 43 days of age, were infected intratracheally with 10(6) and 10(9) cells of R. equi IMV strain A5, respectively. The foal infected with 10(9) cells of strain A5 became clinically ill, with the onset of illness (pyrexia and depression) occurring 21 days after inoc...
