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.
Smarsh DN, Kenny LB, Spindler M, Poh KC, Machtinger ET.There is limited data on current knowledge of Pennsylvania horse caretakers on tick-borne diseases (TBDs), tick identification, and tick management practices. This study aimed to determine tick knowledge, concern, and management among Pennsylvania equine caretakers using an online survey. Descriptive statistics and one-way ANOVA tests were used to analyze data. The survey received 894 responses (539 completed) from Pennsylvania equine owners and caretakers. The largest proportion of respondents cared for 3-5 horses (31%), followed by 2 horses (27%). Veterinarian-confirmed diagnosis rates of tw...
Normand C, Thieulent CJ, Fortier C, Sutton G, Senamaud-Beaufort C, Jourdren L, Blugeon C, Vidalain PO, Pronost S, Hue ES.Equid herpesvirus 4 (EHV-4) is a common respiratory pathogen in horses. It sporadically induces abortion or neonatal death. Although its contribution in neurological disorders is not clearly demonstrated, there is a strong suspicion of its involvement. Despite preventive treatments using vaccines against EHV-1/EHV-4, the resurgence of alpha-EHV infection still constitutes an important threat to the horse industry. Yet very few studies have been conducted on the search for antiviral molecules against EHV-4. A screening of 42 antiviral compounds was performed in vitro on equine fibroblast cells ...
Barradas PF, Marques J, Tavares C, Brito NV, Mesquita JR.The Garrano is a semi-feral horse breed native to several mountains in the northern Iberian Peninsula. Despite being endangered, this unique breed of pony has managed to survive in the wild and continues to be selectively bred, highlighting their remarkable resilience and adaptability to harsh environments. Wildlife plays a critical role in the survival of tick vectors in their natural habitats and the transfer of tick-borne pathogens, as they can serve as reservoir hosts for many agents and amplifiers for these vectors. The semi-feral lifestyle of the Garrano horses makes them particularly vu...
Soliman R, Yousef M, Gelil SA, Aboul-Ella H.Strangles is a highly contagious disease of the equine upper respiratory tract caused by Streptococcus equi subspecies. Streptococcus equi subsp. equi (S. equi) and Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) was isolated, as local, hot, and field strains, from horses clinically suffering from respiratory distress. The isolated Streptococci were identified using bacteriological and molecular techniques. Four formulations of inactivated S. equi vaccines were developed and evaluated. The first formulation was prepared using the S. equi isolates, adjuvanted with MONTANIDE GEL adjuv...
Akbari H, Basaki M, Imani Baran A, Akbarzadeh Z.Anaplasmosis, a tick-borne disease with worldwide distribution, impacts ruminants, equines, carnivores, and humans. This study aimed to investigate Anaplasma phagocytophilum in horses from Ardabil province and Anaplasma ovis in small ruminants from East Azerbaijan province using the Nested Polymerase Chain Reaction (PCR) method. Blood samples were taken from the jugular vein of 100 healthy horses in the Ardabil province and 156 healthy sheep and goats (116 sheep and 40 goats) in the East Azerbaijan province during the spring and summer seasons of 2016 in northwest Iran. The collected blood sam...
Sun J, Xu X, Gao S, Pan Q, Liu Z, Huang Y, Lian Y.Prevotella heparinolytica is a Gram-negative bacterium that is commonly found in the oral, intestinal, and urinary tracts. It has been extensively studied in lower respiratory tract infections in horses, which has heparinolytic activity and can secrete heparinase and further induces virulence factors in cells and causes disease. However, no such cases have been reported in humans. Methods: A 58-year-old male patient from China presented to the respiratory clinic in Suzhou with a productive cough producing white sputum for 20 days and fever for 3 days. Prior to this visit, a chest computed to...
Altay K, Erol U, Sahin OF, Ulucesme MC, Aytmirzakizi A, Aktas M.Tick-borne pathogens (TBP) are an important group of organisms that can affect animals and humans all over the world. Equine piroplasmosis (EP), caused by and , is considered one of the most important tick-borne diseases and can cause significant clinical symptoms and mortality in horses. Moreover, EP plays a restrictive role in international horse traditions and transportation. Although these species can cause similar symptoms, there are different 18S rRNA genotypes of (five genotypes) and (three genotypes). Besides piroplasma species, and hemotropic mycoplasmas (HM) are known as other im...
Chen L, Li S, Li W, Yu Y, Sun Q, Chen W, Zhou H, Wang C, Li L, Xu M, Khan MZ, Li Y, Wang T.The Nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway has been extensively studied for its role in regulating antioxidant and antiviral responses. The Equid herpesvirus type 8 (EqHV-8) poses a significant threat to the equine industry, primarily manifesting as respiratory disease, abortions, and neurological disorders in horses and donkeys. Oxidative stress is considered a key factor associated with pathogenesis of EqHV-8 infection. Unfortunately, there is currently a dearth of therapeutic interventions available for the effective control of EqHV-8. R...
de la Cuesta-Torrado M, Velloso Alvarez A, Neira-Egea P, Cuervo-Arango J.Equine herpesvirus myeloencephalopathy (EHM) has severe impact on the sport horse population. Objective: Study the influence of EHM on the likelihood of affected horses to return to their previous performance and investigate the association of clinical variables with prognosis. Methods: Twenty-six horses positive for equine herpesvirus type 1 (EHV-1) were admitted to a veterinary teaching hospital (VTH) during a natural EHM outbreak at an international jumping event. Methods: Data collected from the VTH, the International Equestrian Federation, and surveys completed by the riders and horse own...
Villalba R, Tena-Tomás C, Ruano MJ, Valero-Lorenzo M, López-Herranz A, Cano-Gómez C, Agüero M.The African horse sickness virus (AHSV) belongs to the Genus Orbivirus, family Sedoreoviridae, and nine serotypes of the virus have been described to date. The AHSV genome is composed of ten linear segments of double-stranded (ds) RNA, numbered in decreasing size order (Seg-1 to Seg-10). Genome segment 2 (Seg-2) encodes outer-capsid protein VP2, the most variable AHSV protein and the primary target for neutralizing antibodies. Consequently, Seg-2 determines the identity of the virus serotype. An African horse sickness (AHS) outbreak in an AHS-free status country requires identifying the seroty...
Mai Z, Fu H, Miao R, Lu C, Zhang X, Yuan Z, Ji P, Hua Y, Wang C, Ma Y, Deng H, Wei Y.Salmonella enterica subspecies enterica serovar abortus equi (S. abortus equi) is one of the main pathogens that causes abortion in pregnant horses and donkeys, which was highly infectious and greatly restricts the healthy development of the horse industry. Objective: In order to investigate the prevalence and biological characteristics of S. abortus equi in different regions and breeds of horses in Xinjiang. Methods: This study conducted ELISA detection of S. abortus equi antibodies on serum samples of 971 horses collected from three large-scale horse farms and five free-range horse farms in ...
Emiru AY, Regassa F, Endebu Duguma B, Kassaye A, Desyebelew B.Effective therapy for many infections is becoming difficult due to the evolutionary development of drug resistance, and hence, the development of alternative treatment options mainly from herbs is crucial. The objective of this study was to investigate the antibacterial effects of ethanol extracts of stem bark, leaves and roots of Combretum molle against Streptococcus equi isolated from clinical cases of strangles using in vitro tests. Methods: Plant extraction was performed using a maceration technique with 80% ethanol. The mean zone of inhibition was determined using the agar well diffusion ...
Muroni G, Serra E, Biggio GP, Sanna D, Cherchi R, Taras A, Appino S, Foxi C, Masala G, Loi F, Chisu V.The members of the family are important pathogens that infect a wide range of vertebrate hosts, including humans. Among them, , historically considered as an avian agent, has recently been identified in livestock, primarily sheep and cattle, but also in horses, with the infection being linked to reproductive disorders, such as abortion, absorption of embryos, stillbirth, and the birth of weak foals. Much less is known about chlamydial infections in the Sardinian equine population. This study aimed to identify the chlamydial diversity in genital samples from asymptomatic Sardinian horses. Howe...
Hassanien RT, Thieulent CJ, Carossino M, Li G, Balasuriya UBR.(1) Background: equid alphaherpesvirus-1 (EHV-1) is a highly contagious viral pathogen prevalent in most horse populations worldwide. Genome-editing technologies such as CRISPR/Cas9 have become powerful tools for precise RNA-guided genome modifications; (2) Methods: we designed single guide RNAs (sgRNA) to target three essential (ORF30, ORF31, and ORF7) and one non-essential (ORF74) EHV-1 genes and determine their effect on viral replication dynamics ; (3) Results: we demonstrated that sgRNAs targeting essential lytic genes reduced EHV-1 replication, whereas those targeting ORF74 had a negligi...
Hellman S, Martin F, Tydén E, Sellin ME, Norman A, Hjertner B, Svedberg P, Fossum C.Stem cell-derived organoid cultures have emerged as attractive experimental models for infection biology research regarding various types of gastro-intestinal pathogens and host species. However, the large size of infectious nematode larvae and the closed structure of 3-dimensional organoids often hinder studies of the natural route of infection. To enable easy administration to the apical surface of the epithelium, organoids from the equine small intestine, i.e. enteroids, were used in the present study to establish epithelial monolayer cultures. These monolayers were functionally tested by s...
Hamad MH, Islam SI, Jitsamai W, Chinkangsadarn T, Naraporn D, Ouisuwan S, Taweethavonsawat P.Mixed strongylid infections significantly impact equine health and performance. Traditional microscopy-based methods exhibit limitations in accurately identifying strongylid species. Nemabiome deep amplicon sequencing approach previously succeeded in describing the strongylid communities in livestock including equids. However, there are no available studies that describe the structural communities of strongylid parasites in horses in Thailand. Therefore, this study was undertaken encompassing the ITS-2 rDNA metabarcoding assay to characterize strongylid species within horse fecal samples colle...
Pelzel-McCluskey AM.Vesicular stomatitis (VS) is a vector-borne livestock disease caused by either VS New Jersey virus or VS Indiana virus. The disease circulates endemically in northern South America, Central America, and Mexico and only occasionally causes outbreaks in the United States. During the past 20 years, VS outbreaks in the southwestern and Rocky Mountain regions occurred periodically with incursion years followed by virus overwintering and subsequent expansion outbreak years. Regulatory response by animal health officials prevents spread from lesioned animals and manages trade impacts. Recent US outb...
Equine influenza (EI) is a highly contagious viral disease of equids characterized by pyrexia and respiratory signs. Like other influenza A viruses, antigenic drift or shift could lead to a vaccine-induced immunity breakdown if vaccine strains are not updated. The aim of this study was to genetically characterize EIV strains circulating in Italy, detected in PCR-positive samples collected from suspected cases, especially in the absence of formal active surveillance. Methods: Between February and April 2019, blood samples and nasal swabs collected from each of the 20 symptomatic horses from Nor...
Rodrigues VS, Trevisan LAC, Cintra BS, Pires RH, Ribeiro AB, Tavares DC, Oberhaus E, Ferreira JC.Cutaneous pythiosis is a life-threatening infectious disease. Low-level laser therapy (LLLT) and ozone (O3) have been used individually in the treatment of infected wounds. The goals of the study were a) to characterize the antimicrobial action of the photo-ozone therapy (LLLT-O3) against equine Pythium insidiosum, and b) to assess the cytotoxic potential of the LLLT-O3 in keratinocytes. Specimens of pathogen were isolated from 10 horses. After culturing, 120 hyphae plugs were distributed among four groups (n=30 hyphae plugs/group): LLLT (laser irradiation for 160 sec;), O3 (exposition to O3 f...
Julia M, Felippe B.The clinical manifestation of recurrent fevers and infections alerts the clinician to the possibility of an underlying immunodeficiency. Common variable immunodeficiency (CVID) in the horse is a rare late-onset, non-familial immunologic disorder of B cell depletion and/or dysfunction with resultant inadequate antibody production. The most common clinical presentations in horses with CVID are recurrent upper and/or lower respiratory infections, meningitis and/or ataxia, cholangiohepatitis, infectious colitis, infectious dermatitis, and severe gastrointestinal parasitism. Immune-mediated and lym...
Hüttl J, Reitt K, Meli ML, Meili T, Bönzli E, Pineroli B, Ginders J, Schoster A, Jones S, Tyson GB, Hosie MJ, Pusterla N, Wernike K....Horses and cattle have shown low susceptibility to SARS-CoV-2, and there is no evidence of experimental intraspecies transmission. Nonetheless, seropositive horses in the US and seropositive cattle in Germany and Italy have been reported. The current study investigated the prevalence of antibodies against SARS-CoV-2 in horses and cattle in Switzerland. In total, 1940 serum and plasma samples from 1110 horses and 830 cattle were screened with a species-specific ELISA based on the SARS-CoV-2 receptor-binding domain (RBD) and, in the case of suspect positive results, a surrogate virus neutralizat...
Mirabal B, Andrade BS, Souza SPA, Oliveira IBDS, Melo TS, Barbosa FS, Jaiswal AK, Seyffert N, Portela RW, Soares SC, Azevedo V, Meyer R, Tiwari S....Equine strangles is a prevalent disease that affects the upper respiratory in horses and is caused by the Gram-positive bacterium . In addition to strangles, other clinical conditions are caused by the two subspecies, and , which present relevant zoonotic potential. Treatment of infections caused by has become challenging due to the worldwide spreading of infected horses and the unavailability of effective therapeutics and vaccines. Penicillin treatment is often recommended, but multidrug resistance issues arised. We explored the whole genome sequence of 18 isolates to identify candidate p...
Carossino M, Vissani MA, Barrandeguy ME, Balasuriya UBR, Parreño V.Group A rotaviruses are a well-known cause of viral gastroenteritis in infants and children, as well as in many mammalian species and birds, affecting them at a young age. This group of viruses has a double-stranded, segmented RNA genome with high genetic diversity linked to point mutations, recombination, and, importantly, reassortment. While initial molecular investigations undertaken in the 1900s suggested host range restriction among group A rotaviruses based on the fact that different gene segments were distributed among different animal species, recent molecular surveillance and genome c...
Gholmohammadi S, Malekifard F, Yakhchali M.Ticks are important ectoparasites in equids, causing economic losses in animal husbandry in Iran and worldwide. This study was aimed to determine frequency and species diversity of hard ticks in equids in Ardabil province, during the four seasons in 2021. A total of 240 equids (187 horses, 53 donkeys) were randomly selected and examined. Ixodid ticks were collected from body surface of examined animals and identified. Of all examined equids, 32.5% horses, and 4.58% donkeys were infested with a total number of 412 ixodid ticks. Tick indices (tick number per animal) were 4.62. There was signific...
Hifumi T, Tanaka T, Suzu I, Sato M, Akioka K, Fujimata C, Shinkai R, Maeda T, Kusakisako K, Ikadai H, Miyoshi N.Alveolar echinococcosis is a zoonotic disease caused by a larval-stage infection. Geographical haplotyping targeting the parasite's mitochondrial cytochrome () gene has been reported for isolates from definitive and intermediate hosts (wild canids and rodents); however, there are limited reports on strain typing for the dead-end host, the horse, which could act as a sentinel for E. Accordingly, we investigated the diversity of in isolates obtained from slaughtered Japanese and Canadian horses originating from the Iburi and Hidaka regions in Hokkaido and from Alberta, respectively, with PCR ...
Lebrasseur O, More KD, Orlando L.Equine viral outbreaks have disrupted the socio-economic life of past human societies up until the late 19th century and continue to be of major concern to the horse industry today. With a seroprevalence of 60-80 per cent, equine herpesvirus 4 (EHV-4) is the most common horse pathogen on the planet. Yet, its evolutionary history remains understudied. Here, we screen the sequenced data of 264 archaeological horse remains to detect the presence of EHV-4. We recover the first ancient EHV-4 genome with 4.2× average depth-of-coverage from a specimen excavated in the Southeastern Urals and dated ...
West Nile virus (WNV) is a globally significant mosquito-borne Flavivirus that causes West Nile disease (WND). In Libya, evidence of WNV circulation has been reported in humans but never in animals. The aim of this study was to determine the seroprevalence of WNV infection in horses and dogs in Libya. In total, 574 and 63 serum samples were collected from apparently healthy, unvaccinated horses and dogs, respectively, between 2016 and 2019. A commercially available competitive enzyme-linked immunosorbent assay (c-ELISA) kit was initially used to test the collected samples for the presence of W...
Elliott S, Olufemi OT, Daly JM.Vaccines against equine influenza have been available since the late 1960s, but outbreaks continue to occur periodically, affecting both vaccinated and unvaccinated animals. The aim of this study was to systematically evaluate the efficacy of vaccines against influenza A virus in horses (equine IAV). For this, PubMed, CAB abstracts, and Web of Science were searched for controlled trials of equine IAV vaccines published up to December 2020. Forty-three articles reporting equine IAV vaccination and challenge studies in previously naïve equids using an appropriate comparison group were included ...
Kydd JH, Townsend HG, Hannant D.Equine herpesvirus-1 (EHV-1) is an alphaherpesvirus which infects horses, causing respiratory and neurological disease and abortion in pregnant mares. Latency is established in trigeminal ganglia and lymphocytes. Immunity to EHV-1 lasts between 3 and 6 months. Current vaccines, many of which contain inactivated virus, have reduced the incidence of abortion storms in pregnant mares but individual animals, which may be of high commercial value, remain susceptible to infection. The development of effective vaccines which stimulate both humoral and cellular immune responses remains a priority. Uti...
Laus F, Veronesi F, Passamonti F, Paggi E, Cerquetella M, Hyatt D, Tesei B, Fioretti DP.In order to investigate the prevalence of tick-borne diseases, equine piroplasmosis, equine granulocytic anaplasmosis and Lyme borreliosis in Central Italy, blood samples from 300 horses were analyzed for the presence of antibodies against Babesia caballi, Theileria equi, Anaplasma phagocytophilum and Borrelia burgdorferi using the IFAT. The blood samples were also subjected to PCR assays in order to detect pathogen DNA. A total of 78 (26.0%) and 123 (41.0%) horses were found to be seropositive for B. caballi and T. equi, respectively, while 41 (13. 4%) and 21 (7.0%) horses were, respectively,...
Tenzin , Sharma B, Dhand NK, Timsina N, Ward MP.From January through July 2008, rabies reemerged in the Chhukha district of southwestern Bhutan. To clarify the distribution and direction of spread of this outbreak, we mapped reported cases and conducted directional tests (mean center and standard deviational ellipse). The outbreak resulted in the death of 97 animals (42 cattle, 52 dogs, and 3 horses). Antirabies vaccine was given free of charge to ≈674 persons suspected to have been exposed. The outbreak spread south to north and appeared to follow road networks, towns, and areas of high human density associated with a large, free-roaming...
Donadieu E, Bahuon C, Lowenski S, Zientara S, Coulpier M, Lecollinet S.West Nile virus (WNV) is a neurotropic flavivirus that cycles between mosquitoes and birds but that can also infect humans, horses, and other vertebrate animals. In most humans, WNV infection remains subclinical. However, 20%-40% of those infected may develop WNV disease, with symptoms ranging from fever to meningoencephalitis. A large variety of WNV strains have been described worldwide. Based on their genetic differences, they have been classified into eight lineages; the pathogenic strains belong to lineages 1 and 2. Ten years ago, Beasley et al. (2002) found that dramatic differences exist...
Greay TL, Zahedi A, Krige AS, Owens JM, Rees RL, Ryan UM, Oskam CL, Irwin PJ.Apicomplexan tick-borne pathogens that cause disease in companion animals include species of Babesia Starcovici, 1893, Cytauxzoon Neitz & Thomas, 1948, Hepatozoon Miller, 1908 and Theileria Bettencourt, Franca & Borges, 1907. The only apicomplexan tick-borne disease of companion animals that is known to occur in Australia is babesiosis, caused by Babesia canis vogeli Reichenow, 1937 and Babesia gibsoni Patton, 1910. However, no molecular investigations have widely investigated members of Apicomplexa Levine, 1980 in Australian ticks that parasitise dogs, cats or horses, until this present inves...
Kelly C, Bugg M, Robinson C, Mitchell Z, Davis-Poynter N, Newton JR, Jolley KA, Maiden MC, Waller AS.Improved understanding of the epidemiology of Streptococcus equi transmission requires sensitive and portable subtyping methods that can rationally discriminate between strains. S. equi is highly homogeneous and cannot be distinguished by multilocus enzyme electrophoretic or multilocus sequence-typing methods that utilize housekeeping genes. However, on sequence analysis of the N-terminal region of the SeM genes of 60 S. equi isolates from 27 strangles outbreaks, we identified 21 DNA codon changes. These resulted in the nonsynonymous substitution of 18 amino acids and allowed the assignment of...
Gimenez C, Casado N, Criado-Fornelio A, de Miguel FA, Dominguez-Peñafiel G.This study reports a molecular survey of Hepatozoon species and of the order Piroplasmida in the Province of Burgos, northern Spain. The diagnostic techniques employed included PCR and the sequencing of the 18S rRNA gene. Eighty-nine blood samples from domestic animals plus 138 blood/coagulated blood samples from wild mammals were examined. Theilerid protozoa were found at relatively high frequencies in bovines (14.6%) and horses (36%). Theileria buffeli, T. sergenti and T. annulata were diagnosed in cows. T. equi was common in horses and T. annae was found in a donkey for the first time. A ne...
Lu J, Guo Z, Pan X, Wang G, Zhang D, Li Y, Tan B, Ouyang L, Yu X.Avian influenza virus H5N1 has demonstrated considerable pandemic potential. Currently, no effective vaccines for H5N1 infection are available, so passive immunotherapy may be an alternative strategy. To investigate the possible therapeutic effect of antibody against highly pathogenic H5N1 virus on a mammal host, we prepared specific equine anti-H5N1 IgGs from horses vaccinated with inactivated H5N1 virus, and then obtained the F(ab')2 fragments by pepsin digestion of IgGs. Methods: The horses were vaccinated with inactivated H5N1 vaccine to prepare anti-H5N1 IgGs. The F(ab')2 fragments were p...
Collins PJ, Vachieri SG, Haire LF, Ogrodowicz RW, Martin SR, Walker PA, Xiong X, Gamblin SJ, Skehel JJ.In 2004 an hemagglutinin 3 neuraminidase 8 (H3N8) equine influenza virus was transmitted from horses to dogs in Florida and subsequently spread throughout the United States and to Europe. To understand the molecular basis of changes in the antigenicity of H3 hemagglutinins (HAs) that have occurred during virus evolution in horses, and to investigate the role of HA in the equine to canine cross-species transfer, we used X-ray crystallography to determine the structures of the HAs from two antigenically distinct equine viruses and from a canine virus. Structurally all three are very similar with...
Ripoll CM, Remondegui CE, Ordonez G, Arazamendi R, Fusaro H, Hyman MJ, Paddock CD, Zaki SR, Olson JG, Santos-Buch CA.Between November 1993 and March 1994, a cluster 6 pediatric patients with acute febrile illnesses associated with rashes was identified in Jujuy Province, Argentina. Immunohistochemical staining of tissues confirmed spotted fever group rickettsial infection in a patient with fatal disease, and testing of serum of a patient convalescing from the illness by using an indirect immunofluorescence assay (IFA) demonstrated antibodies reactive with spotted fever group rickettsiae. A serosurvey was conducted among 16 households in proximity to the index case. Of 105 healthy subjects evaluated by IFA, 1...
Arroyo LG, Kruth SA, Willey BM, Staempfli HR, Low DE, Weese JS.Molecular typing of Clostridium difficile isolates from animals and humans may be useful for evaluation of the possibility for interspecies transmission. The objective of this study was to evaluate C. difficile isolates from domestic animals and humans using PCR ribotyping. Isolates were also tested using PCR for the presence of genes encoding toxins A and B. One hundred and thirty-three isolates of C. difficile from dogs (n = 92), horses (n = 21) and humans (n = 20), plus one each from a cat and a calf, were evaluated. Overall, 23 ribotypes were identified. Of these, nine were identified from...
Maddox TW, Clegg PD, Diggle PJ, Wedley AL, Dawson S, Pinchbeck GL, Williams NJ.The increasing prevalence of antimicrobial-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and antimicrobial-resistant Escherichia coli represents a significant problem. However, the carriage of such bacteria by horses in the UK has not been well characterised. Objective: To estimate the prevalence of nasal carriage of MRSA and faecal carriage of antimicrobial-resistant E. coli amongst horses in the general equine community of the mainland UK. Methods: A cross-sectional study of horses recruited by 65 randomly selected equine veterinary practices was conducted, wi...
Wang LF, Michalski WP, Yu M, Pritchard LI, Crameri G, Shiell B, Eaton BT.In 1994, a new member of the family Paramyxoviridae isolated from fatal cases of respiratory disease in horses and humans was shown to be distantly related to morbilliviruses and provisionally called equine morbillivirus (K. Murray et al., Science 268:94-97, 1995). To facilitate characterization and classification, the virus was purified, viral proteins were identified, and the P/V/C gene was cloned and sequenced. The coding strategy of the gene is similar to that of Sendai and measles viruses, members of the Paramyxovirus and Morbillivirus genera, respectively, in the subfamily Paramyxovirina...
Moretti A, Mangili V, Salvatori R, Maresca C, Scoccia E, Torina A, Moretta I, Gabrielli S, Tampieri MP, Pietrobelli M.Babesia caballi and Theileria equi are the causative agents of equine piroplasmosis. In this preliminary epidemiological study, 412 horses reared in central and northern Italy were sampled and three diagnostic methods compared, namely, the microscopy, the indirect fluorescent antibody test (IFAT) and a PCR. Possible risk factors (such as area, season, breed, activity, sex, age, and grazing) associated with serological positivity were evaluated. A seroprevalence of 68.4% was found: 12.4% of the animals had anti-T. equi antibodies, 17.9% anti-B. caballi antibodies and 38.1% had antibodies agains...
Lyons S, Kapoor A, Schneider BS, Wolfe ND, Culshaw G, Corcoran B, Durham AE, Burden F, McGorum BC, Simmonds P.Non-primate hepacivirus (NPHV), equine pegivirus (EPgV) and Theiler's disease associated virus (TDAV) are newly discovered members of two genera in the Flaviviridae family, Hepacivirus and Pegivirus respectively, that include human hepatitis C virus (HCV) and human pegivirus (HPgV). To investigate their epidemiology, persistence and clinical features of infection, large cohorts of horses and other mammalian species were screened for NPHV, EPgV and TDAV viraemia and for past exposure through serological assays for NPHV and EPgV-specific antibodies. NPHV antibodies were detected in 43% of 328 ho...
Harris SR, Robinson C, Steward KF, Webb KS, Paillot R, Parkhill J, Holden MT, Waller AS.Strangles, the most frequently diagnosed infectious disease of horses worldwide, is caused by Streptococcus equi. Despite its prevalence, the global diversity and mechanisms underlying the evolution of S. equi as a host-restricted pathogen remain poorly understood. Here, we define the global population structure of this important pathogen and reveal a population replacement in the late 19th or early 20th Century. Our data reveal a dynamic genome that continues to mutate and decay, but also to amplify and acquire genes despite the organism having lost its natural competence and become host-rest...
Lyons ET, Tolliver SC, Drudge JH.Small strongyles are highly prevalent in horses and can be found worldwide. Even though over 50 species of these parasites have been described, about 10 species comprise the bulk of the total number present in horses. Efforts to control small strongyles and other equine internal parasites have been undertaken for many years. Some of the early medications and control measures provided questionable activity against endoparasites; whether effective or not, they could be detrimental to the horse. Beginning in the early 1900s, scientific effort was used to evaluate activity of antiparasitic compoun...
Rizk MA, El-Sayed SA, Terkawi MA, Youssef MA, El Said el Sel S, Elsayed G, El-Khodery S, El-Ashker M, Elsify A, Omar M, Salama A, Yokoyama N....A rapid and accurate assay for evaluating antibabesial drugs on a large scale is required for the discovery of novel chemotherapeutic agents against Babesia parasites. In the current study, we evaluated the usefulness of a fluorescence-based assay for determining the efficacies of antibabesial compounds against bovine and equine hemoparasites in in vitro cultures. Three different hematocrits (HCTs; 2.5%, 5%, and 10%) were used without daily replacement of the medium. The results of a high-throughput screening assay revealed that the best HCT was 2.5% for bovine Babesia parasites and 5% for equ...
Turner CE, Kurupati P, Wiles S, Edwards RJ, Sriskandan S.Currently there is no licensed vaccine against the human pathogen Streptococcus pyogenes. The highly conserved IL-8 cleaving S. pyogenes cell envelope proteinase SpyCEP is surface expressed and is a potential vaccine candidate. A recombinant N-terminal part of SpyCEP (CEP) was expressed and purified. AntiCEP antibodies were found to neutralize the IL-8 cleaving activity of SpyCEP. CEP-immunized mice had reduced bacterial dissemination from focal S. pyogenes intramuscular infection and intranasal infection. We also identified a functional SpyCEP-homolog protease SeCEP, expressed by the equine p...
Guthrie AJ, Quan M, Lourens CW, Audonnet JC, Minke JM, Yao J, He L, Nordgren R, Gardner IA, Maclachlan NJ.We describe the development and preliminary characterization of a recombinant canarypox virus vectored (ALVAC) vaccine for protective immunization of equids against African horse sickness virus (AHSV) infection. Horses (n=8) immunized with either of two concentrations of recombinant canarypox virus vector (ALVAC-AHSV) co-expressing synthetic genes encoding the outer capsid proteins (VP2 and VP5) of AHSV serotype 4 (AHSV-4) developed variable titres (<10-80) of virus-specific neutralizing antibodies and were completely resistant to challenge infection with a virulent strain of AHSV-4. In contra...
Beck C, Leparc Goffart I, Franke F, Gonzalez G, Dumarest M, Lowenski S, Blanchard Y, Lucas P, Lamballerie X, Grard G, Durand GA, Zientara S....Since 2015, annual West Nile virus (WNV) outbreaks of varying intensities have been reported in France. Recent intensification of enzootic WNV circulation was observed in the South of France with most horse cases detected in 2015 ( = 49), 2018 ( = 13), and 2019 ( = 13). A WNV lineage 1 strain was isolated from a horse suffering from West Nile neuro-invasive disease (WNND) during the 2015 episode in the Camargue area. A breaking point in WNV epidemiology was achieved in 2018, when WNV lineage 2 emerged in Southeastern areas. This virus most probably originated from WNV spread from Northern Ital...
Nielsen MK, Kaplan RM, Thamsborg SM, Monrad J, Olsen SN.Development of resistance to anthelmintic drugs by horse strongyles constitutes a growing threat to equine health because it is unknown when new drug classes can be expected on the market. Consequently, parasite control strategies should attempt to maintain drug efficacy for as long as possible. The proportion of a parasite population that is not exposed to anthelmintic treatment is described as being "in refugia" and although many factors affect the rate at which resistance develops, levels of refugia are considered the most important as these parasites are not selected by treatment and so pr...
Reed SM, Toribio RE.Equine herpesvirus infections in horses remain a significant cause of abortion and neurologic disease. These viruses are also responsible for mild signs of respiratory disease. The ability to establish latent infections with periodic reactivation or transmission to other horses is an important feature of these herpesviruses. One of the most unique aspects of this report is the description of horses demonstrating neurologic signs serving as the source of infection for other horses. Accurate diagnosis and better means of protection for horses remain problems facing veterinarians and horse owners...
Knowles DP, Kappmeyer LS, Stiller D, Hennager SG, Perryman LE.Horses infected with Babesia equi were previously identified by the presence of antibodies reactive with a merozoite surface protein epitope (D. P. Knowles, Jr., L. E. Perryman, L. S. Kappmeyer, and S. G. Hennager. J. Clin. Microbiol. 29:2056-2058, 1991). The antibodies were detected in a competitive inhibition enzyme-linked immunosorbent assay (CI ELISA) by using monoclonal antibody 36/133.97, which defines a protein epitope on the merozoite surface. The gene encoding this B. equi merozoite epitope was cloned and expressed in Escherichia coli. The recombinant merozoite protein, designated equ...
Rushton JO, Lecollinet S, Hubálek Z, Svobodová P, Lussy H, Nowotny N.An unexpectedly high infection rate (26.1%) of tick-borne encephalitis virus (TBEV) was identified in a herd of 257 horses of the same breed distributed among 3 federal states in Austria. Young age (p<0.001) and male sex (p=0.001) were positively associated with infection.
Roy MF, Kwong GP, Lambert J, Massie S, Lockhart S.Despite its widespread use in equine medicine, the clinical value of the systemic inflammatory response syndrome (SIRS) concept in horses remains unknown. Objective: To study the prognostic value of measures of SIRS in horses and identify the best model of severe SIRS to predict outcome. Methods: A total of 479 consecutive adult horse emergency admissions to a private primary referral practice. Methods: Prospective observational study. All adult horses admitted for emergency treatment over the study period were included. Multivariate logistic regression and stepwise model selection were used. ...
Frederick J, Giguère S, Sanchez LC.Diarrhea is common in foals but there are no studies investigating the relative prevalence of common infectious agents in a population of hospitalized diarrheic foals. Objective: To determine the frequency of detection of infectious agents in a population of hospitalized foals with diarrhea and to determine if detection of specific pathogens is associated with age, outcome, or clinicopathologic data. Methods: Two hundred and thirty-three foals < or = 10 months of age with diarrhea examined at a referral institution. Methods: Retrospective case series. Each foal was examined for Salmonella s...
