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.
Science (New York, N.Y.)July 19, 1946
Volume 104, Issue 2690 53-54 doi: 10.1126/science.104.2690.53
Sulkin SE, Goth A, Zarafonetis C.Anesthesia, by ether, is effective in the treatment of western equine encephalomyelitis in mice. Of mice treated with deep ether anesthesia soon after the intracerebral injection of western equine virus, only 58 per cent developed the disease as compared with 92.4 per cent of control animals. When anesthesia was delayed the approximate length of the incubation period, 60 per cent of the animals developed the disease as compared with 92.4 per cent of the controls. In addition, ether anesthesia delays the development of central nervous system symptoms not only when administered soon after the in...
HENNING MW.1. Two outbreaks of infectious equine abortions are reported; both
with a very high abortion incidence.
2. In the majority of the abortions studied the foetal organs were found
to be extensively invaded by S. abortus-equi but in others this organism
could not be recovered from the foetus or after-birth.
3. Both donkey and horse mares were found to be susceptible, donkeys
being on the whole more resistant than horses.
4. Abortion was successfully produced in both horse and donkey mares
by means of (a) the oral administration of minced abortus-equi infected
foetal organs (4 cas...
Tarillion M, Hertzsch R, Richter A.Since 28.01.2022, veterinary medicinal products must be used in accordance with the conditions of authorization (Regulation (EU) 2019/6, Article 106). This entails further restrictions on therapeutic freedom, e. g., with regard to dose deviations. To date, there is no data available in equine medicine on the scope of off-label use as any use deviating from the expert information for antibiotics, on the basis of which the feasibility of implementing the new regulations in Germany can be assessed.To collect data on the off-label use of antibiotics, a Germany-wide anonymous online survey was th...
Baptiste KE, Kyvsgaard NC, Ahmed MO, Damborg P, Dowling PM.Rifampin is an enigma among antimicrobials. Blood and tissue compartment concentrations are a "moving target" along the treatment course due to the complex pharmacodynamic interactions within the body. Rifampin concomitant therapies are for the prevention and treatment of Rhodococcus equi infection in foals, for nearly 40 years. The necessity of rifampin concomitant therapies is based on beliefs that both antimicrobials (e.g., rifampin plus macrolide) penetrate into pulmonary abscesses and intracellular compartments above R. equi minimum inhibitory concentrations (MICs), as well as better ef...
Kutumbetov L, Myrzakhmetova B, Tussipova A, Zhapparova G, Tlenchiyeva T, Bissenbayeva K, Nurabayev S, Kerimbayev A.Equine rhinopneumonia, caused by equine herpesvirus types 1 and 4 (EHV-1 and EHV-4), continues to be a significant health and economic concern in the global equine industry, particularly in Kazakhstan. While vaccines targeting EHV-1 are available, there is currently no licensed monovalent vaccine for EHV-4, and existing formulations offer limited protection against this serotype. This study aimed to develop and evaluate a freeze-dried, live-attenuated EHV-4 vaccine with improved safety, stability, and immunogenicity. Methods: A field isolate of EHV-4 was attenuated through serial passaging in ...
Clarysse M, Bertier P, Verpaele S, Madsen AM, Vlaminck L.Equine dental disorders, such as sharp enamel points and focal overgrowths, are common in horses and are often treated with motorized dental grinding tools. These tools, while effective, produce dust and aerosols that may pose health risks to veterinarians and nearby individuals. This study aimed to assess the health risks associated with dental dust and aerosols generated during equine odontoplasty. Using a realistic setup, air concentrations of inhalable and respirable dust, crystalline silica, and airborne microorganisms and endotoxins were measured in 12 groups of horses undergoing odontop...
de Souza Lima E, de Oliveira Filho RB, Malta KC, Pires IC, Rosa DS, Chideroli RT, Aburjaile FF, de Jesus Sousa T, Ramos RTJ, Góes-Neto A....Corynebacterium pseudotuberculosis is a bacterium that causes significant economic damage to farmers, mainly in the semiarid region of Northeastern Brazil. In this context, only biovar ovis has been reported, and it is widespread in small ruminants. However, this report describes the first equine case in Brazil attributable to a biovar equi. Clinically, it is the causative agent of ulcerative lymphangitis, mastitis, necrotic and ulcerative dermatitis. A Quarter Horse from the semiarid Northeast presented ulcerative lymphangitis. Culture, nitrate reduction test, MALDI-TOF, and whole-genome sequ...
Guayaquil G, Chávez C, Enríquez S, Arrivillaga-Henríquez J, Vaca F, Eleizalde MC, Mendoza M, Pedelini L, Martínez-Fresneda M, Uzcanga GL....Trypanosoma evansi, a protozoan parasite of the Trypanozoon subgenus, infects domestic and wild animals, and occasionally humans, worldwide. Despite its significant impact on livestock production, epidemiological studies and molecular analyses of T. evansi based on variant surface glycoproteins (VSG) remain limited in South America. We report the first molecular identification of T. evansi in two localities in the Ecuadorian Amazon and provide phylogenetic and structural analyses of the VSG RoTat 1.2 fragment. Using a retrospective biobank approach, we analyzed DNA from blood samples of dogs a...
Akinniyi OO, Lawal TR, Rufai N, Jolayemi KO, Amaje J.African horse sickness (AHS) is endemic in Nigeria. Despite this, little is known about the perspective of horse handlers in Nigeria regarding AHS. The study aimed to evaluate the knowledge, attitudes, and perceptions (KAP) of horse handlers in Southwest Nigeria regarding AHS. A cross-sectional survey study was conducted, which involved convenient sampling of 131 horse handlers in Lagos and Oyo States by February - April 2024. The pre-validated questionnaires were administered via face-to-face interviews, covering demographics, knowledge of AHS transmission, clinical signs, prevention and cont...
Hoxha I, Xhekaj B, Muja-Bajraktari N, Sekulin K, Unterköfler MS, Schlamadinger L, Situmorang T, Fuehrer HP, Obwaller AG, Camp JV, Walochnik J....West Nile virus (WNV, family Flaviviridae) is the most geographically widespread arbovirus affecting humans. It circulates between wild birds and mosquitoes, while humans and horses are dead-end hosts. In recent years, several outbreaks have been reported from European countries, including the Balkan Peninsula. In the Republic of Kosovo, a southern Balkan country, data on WNV are scarce, and neither mosquito monitoring nor WNV surveillance is established. To address this gap, we aimed to assess a first monitoring approach that should set the basis and support future large-scale activities in t...
Zhang XX, Huang X, Li XQ, Wang ZY, Jiang Y, Jiao X, Li Q, Wang J, Zhong FG.Salmonella enterica serovar Kentucky ST198 has been increasingly reported in diverse sources worldwide, emerging as a globally epidemic clone. In this study, we aim to characterise the first isolated S. Kentucky ST198 strain from a horse in China. Methods: Twelve faecal samples were collected from horses at a farm in Shihezi, Xinjiang Province, China, and investigated for the presence of Salmonella. The minimum inhibitory concentrations of 15 antimicrobial agents were determined using the broth microdilution method. The whole genome of Sal140 was sequenced using the Illumina Hiseq platform and...
Crisman EC, Furr M, Ramachandran A.To determine the seroprevalence of Francisella tularensis in horses in Oklahoma and to describe factors associated with seropositivity. Unassigned: In this observational study, 238 frozen equine serum samples were tested for F tularensis by microagglutination assay (MAT). Samples were collected from 36 of 77 Oklahoma counties from 2021 through 2023. Exclusion criteria included insufficient sample quantity, cross-reactivity to Brucella abortus, and county outside of Oklahoma. The Fisher exact test was used to compare the proportion of positive tests by year, river basin, and topographic region....
Nemoto M, Kawanishi N, Kambayashi Y, Bannai H, Yamanaka T, Garvey M, Cullinane A, Yamayoshi S, Kawaoka Y, Tsujimura K.Reverse genetics (RG) technology is useful for quickly updating influenza vaccine strains. A high-yield backbone (i.e., six segments other than hemagglutinin and neuraminidase) derived from A/Puerto Rico/8/1934 (PR8) has been developed to improve the growth of avian and human influenza viruses. However, for equine influenza virus (EIV), an EIV-derived backbone may have better growth properties due to more-natural segment combinations. We compared the growth properties in eggs between the PR8 backbone and an EIV backbone from A/equine/Ibaraki/1/2007, a vaccine strain in Japan. The results showe...
Hildebrandt D, Venner M, Hart KA, Berghaus L.Early and specific diagnosis of bronchopneumonia in foals is important to prevent severe disease. In human medicine, C-reactive protein (CRP) and interleukin-6 (IL-6) are important diagnostic and prognostic biomarkers in neonatal pneumonia in other species. Evaluation of these markers in foals with naturally occurring respiratory diseases is lacking. Objective: To determine if CRP and IL-6 were useful predictors of respiratory disease in foals from birth to weaning. Methods: Prospective cohort study. Methods: Periodic blood samples from 200 initially healthy foals were collected from birth to ...
Golen GS, Erganiş O, Balevi A. is an important bacterial pathogen and causes severe chronic granulomatous pneumonia in foals below 6 months of age. It has also become an opportunistic and emerging pathogen in immunocompromised humans. Vaccination is the most cost-effective strategy for controlling and preventing this infection. Although several potential virulence genes and candidate immunogens have been identified over the years, no effective vaccine is currently available to prevent disease in horses. Recently, bacterial vector vaccines have been shown to be promising for In this study, the gene of was cloned into P...
Celik F, Karabulut B, Uslug M, Cankaya E, Eroksuz Y, Simsek S. is a parasitic cestode primarily maintained within an equine-canine life cycle, with horses, donkeys, mules, and other ungulates serving as intermediate hosts. Although has historically been considered non-zoonotic, recent molecular studies suggest that this assumption may need to be reevaluated. This study aimed to investigate the presence and molecular characterization of in equids from Türkiye. A retrospective analysis of 52 equine necropsies performed between 2020 and 2025 identified hydatid cysts in one Arabian horse and two donkeys. Gross and histopathological examination confirmed t...
Duaso J, Perez-Ecija A, Navarro A, Martínez E, De Las Heras A, Mendoza FJ.Equine piroplasmosis (EP), caused by and , is a worldwide tick-borne disease with severe economic, commercial, and sanitary implications for equids. Although diagnosis is based on direct (blood smear or PCR) or indirect (serology) methods, these techniques are expensive, laborious, and false-negative and false-positive results can be yielded. Biochemistry blood profiles are routinely performed in horses. Biochemical parameters and ratios could be a reliable complementary diagnostic tool to assist clinicians in EP diagnosis, mainly in endemic areas, or for discarding similar disorders (piro-li...
Silva VVD, Leite DPSBM, Gonçalves LMT, Oliveira PRF, Junior JWP, Mota RA.Glanders, caused by Burkholderia mallei, is a zoonotic disease with profound socioeconomic and public health implications, affecting equines and humans. This study investigated glanders cases in Brazil from 2006 to 2023 to identify persistent clusters and analyze temporal trends, providing a foundation for the formulation of effective control policies. Official data were obtained from the National Animal Health Information System (SIZ) and Brazilian Institute of Geography and Statistics (IBGE), encompassing case notifications and equine population statistics by state and year. The incidence ri...
Scupham AJ.Many viruses mutate rapidly to adapt to host defenses, and for some of these viruses, the result is long-term infection in individual hosts. The work described here examines the infection and long-term maintenance of a newly identified virus, equine parvovirus-hepatitis (EqPV-H), in an individual horse. This description is possible because of a hypervariable region in the capsid gene; sequence variants were tracked by high-throughput sequencing of serum samples taken over a 16-year period. The data support the hypothesis that EqPV-H infection resulted in a sequence variant bottleneck. The cont...
Mohamed E, Van Cleemput J, Şahin B, Van den Broeck W, Boyen F, Nauwynck H.The equine respiratory and reproductive tract microbiomes are complex and subject to constant fluctuations. Among the microbial inhabitants, subsp. (SEZ) is recognized as the dominant bacterium. It is an opportunistic pathogen that may occasionally lead to various types of infections. A key virulence factor of SEZ is the streptolysin S (SLS) toxin, which is responsible for the characteristic β-hemolysis on blood agar and tissue damage. Viruses and bacteria may interact and aggravate lesions and disease. This study aimed to evaluate the impact of an SLS-containing supernatant from SEZ on the...
Andreas C.The virus that causes African horsesickness does not affect any indigenous species, but produces high mortality among horses, a species introduced by the Dutch East India Company in 1653. While the insect-borne disease did not occur in the immediate vicinity of the Cape Peninsula, horsesickness could have constituted an endemic disease barrier to the horse-based expansion of the colonial sphere into the hinterland, where it was seasonally prevalent. That it did so to only a limited extent is due to a substantial alteration of the ecology of the disease that largely resulted from inadvertent si...
Wilson CS, Carrick J, Begg A, Shearer P, Stewart M, Brookes VJ.Despite emerging disease syndromes in Australian Thoroughbred horses in recent years, there is no formal surveillance for fetal loss in the industry. This study aimed to characterise the distribution of equine pregnancy loss > 45 days of gestation in a major Thoroughbred breeding region to provide insights into causes, prevention, and surveillance feasibility. Methods: Data were collected from 574 fetal loss submissions to veterinary pathology services between February 2015 and November 2021. Variables included date of fetal loss, gestational age, diagnosis, foal weight, and mare age. Dia...
Symoens A, Gauthier ML, Paillette L, Allano M, Lavoie JP, Leclère M.This study aimed to document antimicrobial resistance patterns of bacteria frequently isolated at a referral equine hospital between 2020 and 2022 and to compare these results to those of studies carried out in previous decades at the same reference center. Unassigned: Using the Kirby-Bauer method, 340 tests were completed on bacterial isolates and compared to 233, 255, and 396 tests carried out in 1986 to 1988, 1996 to 1998, and 2007 to 2013, respectively. Data were analyzed with tests for trends, followed by pairwise Fisher tests and Bonferroni corrections. Unassigned: Increasing resistanc...
Chatanga E, Ahedor B, Atabek B, Kainga H, Kapalamula T, Razemba T, Nakao R, Nonaka N, Sivakumar T, Yokoyama N.Equine piroplasmosis (EP) is a tick-borne disease caused by Theileria equi, Theileria haneyi, and Babesia caballi in equids, such as horses, donkeys, mules, and zebras. A comprehensive understanding of the epidemiology of T. equi and B. caballi is vital for EP management. The present study surveyed T. equi and B. caballi infections in donkeys and horses in Malawi. Blood samples were collected from 185 equines, including 178 donkeys in Lilongwe (n = 136) and Dedza (n = 42) districts, and seven horses in Lilongwe district. The blood samples were used to measure hematocrit values and prepare ...
Ganbaatar O, Batbaatar V, Kimura T, Ganzorig S, Tseren-Ochir EO, Suzuki Y, Takai S.ELISA antibody titers against Rhodococcus equi strain ATCC 6939 were measured in serum samples collected from 644 horses aged 1-21 years at 13 provinces and the capital of Mongolia, of which 631 (98%) samples showed values of approximately zero. The mean antibody titers in the 14 areas ranged from -0.08 to -0.01. Nine samples (1.4%) exhibited titers of 0.1-0.2, and surprisingly, four horses (0.6%) each aged 2, 5, 8, and 9 years demonstrated positive values in the range of 0.3-0.8. Considering the age resistance characteristic of this disease, the positive horses were hypothesized to exhibit no...
Johnson A, Karam B, Schroeder O, McKaig L, Loesch K.A 12-month-old miniature horse filly was presented because of laminitis, suspected lymphangitis, and pyrexia. Although the filly's initial physical examination and diagnostic tests suggested an infectious etiology, ultrasonographic findings were suspicious for generalized steatitis. This was confirmed histopathology. The filly experienced full recovery with continued resolution of clinical signs at 18 mo after presentation. This case included aspects similar to those of previously reported clinical presentations, as well as long-term follow-up in a breed that is not overrepresented, providing...
Cooper CJ, Arroyo LG, Hammermueller JD, Botts MM, Pearl DL, Wootton SK, Lillie BN.Equine herpesvirus-1 (EHV-1) is ubiquitous in the horse population, but prevalence estimates have ranged from 3 to 88% depending on the population and method of sampling. No prevalence studies have been carried out in Ontario, Canada. The objective of this study was to measure the prevalence of EHV-1 shedding in healthy broodmares in Ontario. A total of 381 mares from 42 farms in Ontario were sampled, including pregnant and barren broodmares. Samples were collected from the nose, vagina, and blood of each mare up to 6 times from December 2016 through October 2017 using a cross-sectional study ...
Sjolin E, Espinosa D, Arroyo L, Kenney D, Lack A, Baird J.Listeriosis is caused by , a Gram-positive, facultative anaerobic, intracellular rod bacterium that can infect a wide variety of species. Listeriosis occurs in a diverse range of domestic and wild animals but is most commonly a disease of ruminants. Clinical signs include meningoencephalitis, typhlocolitis, septic arthritis, and abortions. Listeriosis in horses has been reported in several countries but is an uncommon diagnosis. This report describes clinical, bacteriological, histopathological, and immunohistochemical findings in 6 foals with neonatal septicemia from which was isolated. Key ...
Planes P, Arsenault J, Allano M, Sauvé F.Biosecurity measures are recommended in stables housing meticillin-resistant Staphylococcus aureus (MRSA)-positive horses, but their feasibility and acceptability, as well as their implementation barriers, remain unclear. Methods: A cross-sectional study was conducted among clients of a veterinary teaching hospital using an online questionnaire. Information on horse activities, stable characteristics and perceptions (feasibility and acceptability scores) of recommended biosecurity measures for MRSA-positive horses was collected. Results: Fifty-seven horse and/or stable owners completed the que...
Almaqhawi AA, El-Jalii IM, Al-Sabi MNS, Al-Ali A, Khalid AM, Abduljawad M, Shawaf T.Equine babesiosis is a widespread protozoan disease in Saudi Arabia. The most common finding of clinical babesiosis is splenomegaly, which can be detected using non-invasive splenic ultrasonography. Unassigned: This study aimed to investigate changes in the spleen size in horses infected with babesiosis using ultrasonography before and after treatment. Unassigned: This study employed 15 male and female Arabian horses. Each animal was examined clinically for clinical signs, and blood samples were collected in plain tubes to detect antibodies against . The spleens of healthy and affected horses ...
Motta D, Aymée L, Roussouliéres I, Di Azevedo MIN, Jacob JCF, Lilenbaum W.Leptospirosis is a zoonotic disease caused by spirochetes of the genus Leptospira. Equine genital leptospirosis (EGL) has been described as a chronic and silent syndrome, presenting reproductive alterations such as abortion, stillbirth, placentitis, embryonic loss, repeat breeding syndrome, and subfertility. This study aimed to investigate the genital Leptospira infection in naturally infected mares with poor reproductive performance, as well as to genetically characterize the agents. A total of 41 mares with a history of poor reproductive performance were selected. Sera were collected for ser...
Healy SR, Yaffy D, Miller HG.Setaria equina is a species of filarial nematode parasite transmitted by mosquitoes, which infects horses and other equids. Adult worms reside in the abdominal cavity with apparently little pathogenic significance, but larvae can migrate to other regions of the body with resulting clinical disease. Cases in the UK are rare, with the last published report in 2001. A recent case of S. equina infection was detected in a 13-year-old, UK-resident mare during postmortem examination in Hertfordshire, UK. Adult worms were collected from the abdominal cavity, their DNA extracted and subjected to PCR an...
