Disease outbreaks in horses refer to the occurrence and spread of infectious diseases within equine populations. These outbreaks can be caused by various pathogens, including bacteria, viruses, and parasites, and can lead to significant health issues in affected horses. Common diseases that may result in outbreaks include equine influenza, equine herpesvirus, strangles, and equine infectious anemia. The transmission of these diseases can occur through direct contact, environmental exposure, or vectors such as insects. Disease outbreaks can have substantial impacts on horse health, welfare, and the equine industry as a whole. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, transmission dynamics, and management strategies associated with disease outbreaks in equine populations.
Zhao S, Smits C, Schuurman N, Barnum S, Pusterla N, Kuppeveld FV, Bosch BJ, Maanen KV, Egberink H.Equine coronavirus (ECoV) is considered to be involved in enteric diseases in foals. Recently, several outbreaks of ECoV infection have also been reported in adult horses from the USA, France and Japan. Epidemiological studies of ECoV infection are still limited, and the seroprevalence of ECoV infection in Europe is unknown. In this study, an indirect enzyme-linked immunosorbent assay (ELISA) method utilizing ECoV spike S1 protein was developed in two formats, and further validated by analyzing 27 paired serum samples (acute and convalescent sera) from horses involved in an ECoV outbreak and 1...
Rossi TM, Moore A, O'Sullivan TL, Greer AL.Infectious respiratory disease is common in young horses and can impact athletic performance and long-term health. Significant variation in the duration of clinical disease has been observed, even in the absence of secondary complications. The determination of factors associated with disease chronicity may facilitate clinical decision-making and the development of improved biosecurity protocols. Objective: To investigate contact network characteristics, and demographic variables associated with time to clinical recovery from Equine Rhinitis A virus respiratory disease. Methods: Prospective coh...
Ikhuoso OA, Monroy JC, Rivas-Caceres RR, Cipriano-Salazar M, Barbabosa Pliego A.Although the strangles disease of Streptococcus equi was discovered many decades ago in 1,251 by Jordanus Ruffus, it has still remained a major frequently diagnosed infection in horses all over the world. The S. equi subspecies pathogen is known to be often resistant to antibiotic treatment, and it makes the antibiotics inefficient; hence, this review was conducted to study how the disease can be managed. The age-long sign of this infection is the oozing of pus through the mucous and skin membranes. Affected horses lose appetite, develop fever, and become depressed, which result in them losin...
Li J, Li Y, Moumouni PFA, Lee SH, Galon EM, Tumwebaze MA, Yang H, Huercha , Liu M, Guo H, Gao Y, Benedicto B, Zhang W, Fan X, Chahan B, Xuan X.Q fever, spotted fever rickettsioses and equine piroplasmosis, are some of the most serious equine tick-borne diseases caused by Coxiella burnetii, Rickettsia spp., Babesia caballi and/or Theileria equi. This study surveyed and molecularly characterized these pathogens infecting horses in ten ranches from XUAR, China using molecular technology. Among 200 horse blood samples, 163 (81.5%) were infected with at least one of the pathogens. Rickettsia spp. was the most prevalent pathogen (n = 114, 57.0%), followed by C. burnetii (n = 79, 39.5%), T. equi (n = 79, 39.5%) and B. caballi (n = 4...
Zimmerli U, Thür B.Equine infectious anaemia (EIA) is a sporadic viral disease in many countries. Every single case has, however, a dramatic impact: infected animals have to be put down, and quarantine restrictions on horse movements lasting three months lead to substantial economic losses. In Switzerland, the mandatory notification was introduced in 1994 in order to facilitate international traffic. A year later, the "new" Ordinance on epizootics of 1995 classified EIA as a "disease to be eradicated". An infected polo horse in the canton of Argovia in summer 2017 thus represented Switzerland's first official ca...
Lohmann KL, James CR, Higgins SN, Howden KJ, Epp T.This retrospective study describes the detection of equine infectious anemia (EIA) during Canadian Food Inspection Agency (CFIA) disease investigations in Canada, examines aspects of importance for disease control, and evaluates potential animal-level risk factors for EIA in high-risk horses. Based on review of all EIA-positive samples and all samples collected during disease investigations (N = 4553) over a 4-year period (2009 to 2012), 409 EIA cases were detected. Horse owners with EIA cases owned between 1 and 60 affected animals, and 49 horses seroconverted during a disease investigation p...
Barbosa Costa G, Marinho PES, Vilela APP, Saraiva-Silva AT, Crispim APC, Borges IA, Dutra AGS, Lobato ZIP, Dos Reis JKP, de Oliveira DB, Drumond BP....Saint Louis encephalitis virus (SLEV) is a mosquito-borne flavivirus that occurs throughout the Americas, and is considered a public health threat. In Brazil, SLEV has been detected from human cases associated with dengue-like disease, but no neurological symptoms were reported. Furthermore, the epidemiology of SLEV in human populations is still poorly explored in the country. We reported serological and molecular detection of SLEV in a healthy population of equids and humans from rural areas in Southeast Brazil. A plaque reduction neutralization test was applied, and neutralizing antibodies w...
Fougerolle S, Fortier C, Legrand L, Jourdan M, Marcillaud-Pitel C, Pronost S, Paillot R.Every year, several epizooties of equine influenza (EI) are reported worldwide. However, no EI case has been identified in France between 2015 and late 2018, despite an effective field surveillance of the pathogen and the disease. Vaccination against equine influenza virus (EIV) remains to this day one of the most effective methods to prevent or limit EI outbreaks and the lack of detection of the pathogen could be linked to vaccination coverage. The aim of this study was to evaluate EI immunity and vaccine coverage in France through a large-scale serological study. A total of 3004 archived sur...
Menezes RC, Campos MP, Popielarczyk M, Kiupel M.We report a new case of cutaneous leishmaniosis caused by Leishmania (Mundinia) martiniquensis in a horse in Florida, USA. A 10-year-old neutered male Quarter horse was presented with multifocal to coalescing, raised, ulcerated and oozing, non-healing wounds on both pinnae of several weeks' duration. After a few months, the lesions regressed spontaneously. Biopsies of the lesions were performed with microscopical findings of epidermal hyperplasia with multifocal ulceration and focally extensive, dermal pyogranulomatous inflammation with numerous intact and degenerate neutrophils being surround...
Porphyre T, Grewar JD.African horse sickness (AHS) is a disease of equids that results in a non-tariff barrier to the trade of live equids from affected countries. AHS is endemic in South Africa except for a controlled area in the Western Cape Province (WCP) where sporadic outbreaks have occurred in the past 2 decades. There is potential that the presence of zebra populations, thought to be the natural reservoir hosts for AHS, in the WCP could maintain AHS virus circulation in the area and act as a year-round source of infection for horses. However, it remains unclear whether the epidemiology or the ecological cond...
Schnabel CL, Babasyan S, Rollins A, Freer H, Wimer CL, Perkins GA, Raza F, Osterrieder N, Wagner B.Equine herpesvirus type 1 (EHV-1) outbreaks continue to occur despite widely used vaccination. Therefore, development of EHV-1 vaccines providing improved immunity and protection is ongoing. Here, an open reading frame 2 deletion mutant of the neuropathogenic EHV-1 strain Ab4 (Ab4ΔORF2) was tested as a vaccine candidate. Three groups of horses ( = 8 each) were infected intranasally with Ab4ΔORF2 or the parent Ab4 virus or were kept as noninfected controls. Horses infected with Ab4ΔORF2 had reduced fever and nasal virus shedding compared to those infected with Ab4 but mounted similar ada...
The UK has never experienced an outbreak of African horse sickness but, as Matthew Robin of the Fyrnwy Equine Clinic explains, there is still a risk of a case occurring.
Dahmani M, Davoust B, Sambou M, Bassene H, Scandola P, Ameur T, Raoult D, Fenollar F, Mediannikov O.Our study aimed to assess the diversity of the species of Anaplasmataceae in Senegal that infect animals and ticks in three areas: near Keur Momar Sarr (northern region), Dielmo and Diop (Sine Saloum, central region of Senegal), and in Casamance (southern region of Senegal). Methods: A total of 204 ticks and 433 blood samples were collected from ruminants, horses, donkeys and dogs. Ticks were identified morphologically and by molecular characterization targeting the 12S rRNA gene. Molecular characterization of species of Anaplasmataceae infecting Senegalese ticks and animals was conducted usin...
Hildebrandt M.The advanced therapy medicinal products (ATMPs) landscape is entirely different from classical drug development. Academia has been the major source of ATMP development, and academic hospitals act as trial sites for the clinical testing of ATMPs, including early academic-led trials as well as industry-sponsored trials that pursue the full developmental pathway to market authorization. The recent breakthrough developments in some ATMPs, such as genetically engineered immune cells, have confronted academic hospitals with a substantial amount of public demand, competitive pressure, and costs. At t...
Spence KL, Cardwell JM, Slater J, Rosanowski SM.The potential for an exotic disease incursion is a significant concern for the United Kingdom (UK) equine industry. Horse owners' perceptions of, and attitudes towards, exotic diseases can influence decisions to adopt disease preparedness strategies. The objectives of this study were to describe horse owners' 1) perceptions of the term 'exotic disease', and 2) attitudes towards their risk of being affected by an exotic disease. In order to address these objectives, qualitative content analysis was undertaken on data collected using two open-ended survey questions. Results: Horse owners (n =â€...
Olguin-Perglione C, Vissani MA, Alamos F, Tordoya MS, Barrandeguy M.Equine influenza is an important cause of respiratory disease of horses worldwide. The equine influenza virus (EIV) undergoes antigenic drift through the accumulation of amino acid substitutions in the viral proteins, which may lead to vaccine breakdown. Objective: To describe the epidemiological findings and the molecular characteristics of the EIV detected during the multifocal outbreak that occurred in Argentina between March and July 2018 and evidence a vaccine breakdown. Methods: Observational, descriptive study. Methods: Virus was detected in nasopharyngeal swabs using real-time reverse ...
Sutton G, Garvey M, Cullinane A, Jourdan M, Fortier C, Moreau P, Foursin M, Gryspeerdt A, Maisonnier V, Marcillaud-Pitel C, Legrand L, Paillot R....Equine herpesvirus 1 (EHV-1) is an Alphaherpesvirus infecting not only horses but also other equid and non-equid mammals. It can cause respiratory distress, stillbirth and neonatal death, abortion, and neurological disease. The different forms of disease induced by EHV-1 infection can have dramatic consequences on the equine industry, and thus the virus represents a great challenge for the equine and scientific community. This report describes the progress of a major EHV-1 outbreak that took place in Normandy in 2009, during which the three forms of disease were observed. A collection of EHV-1...
Browne C, Medlock JM.Last summer saw an unusually high number of cases of West Nile fever in horses and people in south and south-east Europe, but it is too early to tell if this was a one-off increase or a sign of things to come. Here, , , and discuss the various West Nile fever surveillance and control mechanisms in place in the UK.
Gill GS, Singh BB, Dhand NK, Aulakh RS, Sandhu BS, Ward MP, Brookes VJ.Rabies is a devastating zoonotic disease of mammals that causes encephalitis and death. It is endemic in India, with an estimated annual 20,000 human deaths (one-third of the global rabies burden). The magnitude of animal rabies incidence is unknown. In four sub-districts of Punjab, India, we monitored canine and livestock populations from August 15, 2016 to August 14, 2017. Demographic, clinical and rabies diagnostic laboratory (RDL) data were collected from suspected cases of rabies. The annual incidence rate / 10,000 animal years at risk (95% CI) in each sub-district was estimated for each ...
Tirosh-Levy S, Gottlieb Y, Arieli O, Mazuz ML, King R, Horowitz I, Steinman A.Equine piroplasmosis (EP) is an important tick-borne disease of equids, caused by Theileria equi and Babesia caballi. It is endemic in most parts of the world, including Israel, and has clinical and economic consequences. This study was set to evaluate the presence of EP parasites in domestic donkeys and in wild equids in Israel and the Palestinian Authority (PA). To assess subclinical EP infection in 98 domestic donkeys (Equus africanus asinus), 9 Asiatic wild donkeys (Equus hemionus), 8 zebras (Equus quagga), 7 African wild donkeys (Equus africanus) and 5 mules, were tested using PCR and qPC...
Selmi R, Dhibi M, Ben Said M, Ben Yahia H, Abdelaali H, Ameur H, Baccouche S, Gritli A, Mhadhbi M.Livestock constitute habitual hosts and carriers for several infectious pathogens which may represent a serious public health concern affecting the readiness of military forces and lead to wide economic losses. The present report aimed to investigate the prevalence of some haemopathogens infecting military livestock, particularly, dromedaries, sheep and horses using Giemsa-stained blood smears. A total of 300 animals (100 from each species) were selected, clinically examined and sampled. Trypanosoma spp. (22.0%), Anaplasma spp. (17.0%) and Babesia spp. (1.0%) were identified in camels' blood. ...
Paim WP, Weber MN, Cibulski SP, da Silva MS, Puhl DE, Budaszewski RF, Varela APM, Mayer FQ, Canal CW.Horses are often used as blood donors for commercial horse serum (HS) production and to manufacture biologicals. HS is an alternative for fetal bovine serum (FBS) used as a supplement for cell culture and vaccine production. Furthermore, HS is also frequently obtained in order to produce antisera toxins and pathogens. The advent of high-throughput sequencing (HTS) has promoted changes in virus detection, since previous knowledge of targets is not required. Thus, the present study aimed to describe the virome of five different batches of commercial HS from New Zealand (three batches) and Brazil...
With outbreaks of equine influenza continuing to be reported in the UK, Richard Newton and Fleur Whitlock of the Animal Health Trust discusses practical steps that vets can promote and practise to reduce the risk of the virus spreading.
May CE, Guthrie AJ, Schulman ML.We report herein the use of crude extracts obtained from samples of Taylorella equigenitalis-infected horses for the purpose of multi-locus sequence typing (MLST). Samples (n = 36) were collected from horses in South Africa from 1996 to 2017: 34 from genital swabs (stored at -20°C for 2-3 y) and 2 from cryopreserved raw semen aliquots (stored at -70°C for 18 y) prior to assay. The MLST assay showed a single sequence type (ST), designated ST4, that supported a point introduction and thus a common source for the South African outbreak of contagious equine metritis.
Dorey-Robinson DLW, Locker N, Steinbach F, Choudhury B.Equine infectious anaemia virus (EIAV) is a retrovirus with worldwide distribution which is notifiable to the OIE. Despite its importance to the equine industry, most information regarding its biology have been obtained using only two strains (EIAV and EIAV ) from the USA and China, respectively. Recently full genome sequences from Ireland, Italy and Japan have been published; however, this is still not representative of the number of EIAV outbreaks experienced globally each year. The limited availability of published sequences makes design of a universal EIAV PCR difficult, hence diagnosis is...
Bannai H, Tsujimura K, Nemoto M, Ohta M, Yamanaka T, Kokado H, Matsumura T.Equine herpesvirus type 1 (EHV-1) infection is a major cause of pyrexias in winter among Japanese racehorses. In 2014-2015, the Japan Racing Association (JRA) changed the EHV-1 vaccine from an inactivated vaccine to a live vaccine (both produced by Nisseiken). To evaluate the effect of changing the vaccines, the capacities of these vaccines to induce virus-neutralizing (VN) antibodies were compared, and an epizootiological investigation of EHV-1 was performed at the JRA Ritto Training Center during epizootic periods from 2010-2011 to 2016-2017. Results: Three-year-old horses that received the ...
Madani H, Casal J, Alba A, Allepuz A, Cêtre-Sossah C, Hafsi L, Kount-Chareb H, Bouayed-Chaouach N, Saadaoui H, Napp S.Antibodies against bluetongue virus were detected in cattle, sheep, goats, and camels in Algeria in 2008. Antibodies against epizootic hemorrhagic disease virus were detected in cattle, but antibodies against African horse sickness virus were not detected in horses and mules. Epizootic hemorrhagic disease in northern Africa poses a major risk for the European Union.
Dietz WH, Galindo P, Johnson KM.In late June 1973, a small outbreak of equine encephalitis caused by eastern equine encephalomyelitis (EEE) virus occurred in the Republic of Panama. At least 100 horses were affected by the disease and 40 died. More than 1,700 human sera were obtained from areas of virus activity but no serological evidence for infection was found. Four isolates of EEE virus were recovered, one of which was from a small pool of Culex taeniopus mosquitoes. Serologic studies of infected horses and classification by the short incubation hemagglutination-inhibition tests revealed that these isolates were South Am...
Friday PA, Scarratt WK, Elvinger F, Timoney PJ, Bonda A.An outbreak of neurologic disease associated with serologic evidence of equine herpesvirus type 1 (EHV-1) infection occurred in a herd of 46 riding school horses. Ataxia and paresis were observed in 14 geldings and 5 barren mares. Eight affected horses had distal limb edema, 1 horse had a head tilt, and 3 others had urinary incontinence. Other clinical signs included fever, depression, and inappetance in 30 horses. Seven horses with neurologic signs were treated with acyclovir. Serum neutralizing antibody titers against EHV-1 increased 4-fold between acute and convalescent samples or exceeded ...
Soza-Ossandón P, Rivera D, Tardone R, Riquelme-Neira R, GarcÃa P, Hamilton-West C, Adell AD, González-Rocha G, Moreno-Switt AI. is a highly infectious microorganism responsible for many outbreaks reported in equine hospitals. Outbreaks are characterized by high morbidity and mortality rates, nosocomial transmission to other patients, zoonotic transmission to hospital personnel, and even closure of facilities. In this study, 545 samples (environmental and hospitalized patients) were collected monthly during a 1-year period from human and animal contact surfaces in an equine hospital that received local and international horses. A total of 22 isolates were obtained from human contact surfaces (e.g., offices and pharmac...
Bunpapong N, Charoenkul K, Nasamran C, Chamsai E, Udom K, Boonyapisitsopa S, Tantilertcharoen R, Kesdangsakonwut S, Techakriengkrai N, Suradhat S....To investigate an outbreak of African horse sickness (AHS) on a horse farm in northeastern Thailand, we used whole-genome sequencing to detect and characterize the virus. The viruses belonged to serotype 1 and contained unique amino acids (95V,166S, 660I in virus capsid protein 2), suggesting a single virus introduction to Thailand.
Schwarz ER, Long MT.West Nile virus (WNV) neuroinvasive disease threatens the health and well-being of horses and humans worldwide. Disease in horses and humans is remarkably similar. The occurrence of WNV disease in these mammalian hosts has geographic overlap with shared macroscale and microscale drivers of risk. Importantly, intrahost virus dynamics, the evolution of the antibody response, and clinicopathology are similar. The goal of this review is to provide a comparison of WNV infection in humans and horses and to identify similarities that can be exploited to enhance surveillance methods for the early dete...
Vaneechoutte M, Devriese LA, Dijkshoorn L, Lamote B, Deprez P, Verschraegen G, Haesebrouck F.Acinetobacter baumannii was isolated from tips clipped from seven intravenous jugular catheters collected from horses in the Ghent University equine clinic. They originated from seven different horses. Three of the seven showed evidence of local infection.
Patterson-Kane JC, Carrick JB, Axon JE, Wilkie I, Begg AP.The first outbreak of equine influenza virus (EIV) infection was confirmed in Australia in 2007. Some EIV-positive young foals died with bronchointerstitial pneumonia, an rare disease process in this age group that is often postulated to be caused by viral infection. Objective: The aim of this study was to describe post mortem lesions in EIV-infected foals. Methods: Post mortem examinations were conducted on 11 young foals (age 2-12 days) submitted to the Scone Veterinary Hospital, NSW over a 2-month period in 2007. The foals had presented with or developed fatal pneumonia, and were known or s...
Barbić L, Listeš E, Katić S, Stevanović V, Madić J, Starešina V, Labrović A, Di Gennaro A, Savini G.West Nile virus (WNV) is an emerging zoonotic pathogen with rapid global expansion. The virus circulation is confirmed in many countries of Mediterranean Basin and Southern and Central Europe. In our study detection of specific WNV antibodies was performed in horses and cattle sera samples collected from October 2010 to April 2011. Serum samples were randomly taken from different parts of Croatia and tested by IgG and IgM ELISA. Positive serological results were confirmed by virus neutralization assay (VN-assay) and plaque reduction neutralization test (PRNT). Results showed that WNV antibodie...
Pusterla N, Hussey SB, Mapes S, Johnson C, Collier JR, Hill J, Lunn DP, Wilson WD.Recrudescence of latent equine herpesvirus 1 (EHV-1) with subsequent viral shedding via nasal secretions is a potential source of infection for susceptible horses and has been implicated in outbreaks occurring in closed populations. Objective: To describe the viral kinetics of reactivated EHV-1 in blood and nasal secretions from latently infected horses after administration of corticosteroids, and to study the infectious nature of reactivated EHV-1 to sentinel horses. Methods: Eight healthy horses. Methods: Four horses infected 4 months previously with EHV-1 received dexamethasone on 5 consecu...
Carossino M, Lee PY, Nam B, Skillman A, Shuck KM, Timoney PJ, Tsai YL, Ma LJ, Chang HF, Wang HT, Balasuriya UB.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory and reproductive disease of horses. Most importantly, EAV induces abortion in pregnant mares and can establish persistent infection in up to 10-70% of the infected stallions, which will continue to shed the virus in their semen. The objective of this study was to develop and evaluate a reverse transcription insulated isothermal polymerase chain reaction (RT-iiPCR) for the detection of EAV in semen and tissue samples. The newly developed assay had a limit of detection of 10 RNA copies and a 10-fol...
Snyder RE, Feiszli T, Foss L, Messenger S, Fang Y, Barker CM, Reisen WK, Vugia DJ, Padgett KA, Kramer VL.The California Arbovirus Surveillance Program was initiated over 50 years ago to track endemic encephalitides and was enhanced in 2000 to include West Nile virus (WNV) infections in humans, mosquitoes, sentinel chickens, dead birds and horses. This comprehensive statewide program is a function of strong partnerships among the California Department of Public Health (CDPH), the University of California, and local vector control and public health agencies. This manuscript summarizes WNV surveillance data in California since WNV was first detected in 2003 in southern California. From 2003 through ...
Lubelczyk C, Mutebi JP, Robinson S, Elias SP, Smith LB, Juris SA, Foss K, Lichtenwalner A, Shively KJ, Hoenig DE, Webber L, Sears S, Smith RP.From July to September, 2009, an outbreak of eastern equine encephalitis virus (EEEv) occurred in five counties in Maine. The virus was isolated from 15 horses, 1 llama, and pheasants in three separate captive flocks. One wild turkey, screened before translocation, also showed exposure to the virus in January 2010. Two pools of Culiseta melanura (Coquillett) tested positive for EEEv during routine seasonal surveillance in York County in September, but none of the mosquitoes collected during rapid response surveys tested positive. There were more Cs. melanura in July, August, and September 2009...
Azab W, Bedair S, Abdelgawad A, Eschke K, Farag GK, Abdel-Raheim A, Greenwood AD, Osterrieder N, Ali AAH.Equid herpesviruses (EHVs) threaten equine health and can cause significant economic losses to the equine industry worldwide. Different equid herpesviruses, EHV-1, EHV-2, EHV-4 and EHV5 are regularly detected among horse populations. In Egypt, monitoring is sporadic but EHV-1 or EHV-4 have been reported to circulate in the horse population. However, there is a lack of reports related to infection and health status of horses, likely due to the absence of regular diagnostic procedures. In the current study, the circulation of four infectious equid herpesviruses (EHV-1, EHV-2, EHV-4 and EHV-5) am...
HAMMON WM, REEVES WC.In three cases of encephalitis in humans that occurred in the area where the newly described California virus was isolated from mosquitoes, serological evidence seemed to indict the California virus as the etiological agent. In the case of an infant with very severe disease, the serological evidence was convincing; the evidence was almost as strong in the case of a seven-year-old boy; the results in an adult were equivocal. Inapparent infection in man is quite common as indicated by neutralization tests on the sera of nearly 600 residents of California, but encephalitic manifestations of infec...
Kaczensky P, Ganbataar O, Altansukh N, Enkhsaikhan N, Stauffer C, Walzer C.Large mammals re-introduced into harsh and unpredictable environments are vulnerable to stochastic effects, particularly in times of global climate change. The Mongolian Gobi is home to several rare large ungulates such as re-introduced Przewalski's horses (Equus ferus przewalskii) and Asiatic wild asses (Equus hemionus), but also to a millennium-old semi-nomadic livestock herding culture.The Gobi is prone to large inter-annual environmental fluctuations, but the winter 2009/2010 was particularly severe. Millions of livestock died and the Przewalski's horse population in the Gobi crashed. We u...
Endo A, Pecoraro R, Sugita S, Nerome K.The nucleotide and deduced amino acid sequences of the haemagglutinin genes coding for the HA 1 domain of H3N8 equine influenza viruses isolated over wide regions of the world were analyzed in detail to determine their evolutionary relationships. We have constructed a phylogenetic model tree by the neighbour-joining method using nucleotide sequences of 15 haemagglutinin genes, including those of five viruses determined in the present study. This gene tree revealed the existence of two major evolutionary pathways during a twenty five-year period between 1963 to 1988, and each pathway appeared t...
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.
Dávila AM, Silva RA.Animal trypanosome species of economical importance in South America include T. vivax and T. evansi. Both species are described in Brazil, Bolivia, Colombia, French Guyana, Peru, Suriname, and Venezuela. In Argentina and Guyana, only T. evansi and T. vivax are found, respectively. Our studies on T. vivax indicated that the parasite was spreading around 1.3 km per day in Bolivia. We found severe leukopenia in bovines from Pantanal (Brazil) and the Department of Santa Cruz (Bolivia). Because it can cause immunosuppression, the importance of trypanosomiasis control in ensuring success of vaccinat...
Archer DC, Pinchbeck GL, Proudman CJ, Clough HE.Colic is an important cause of mortality and morbidity in domesticated horses yet many questions about this condition remain to be answered. One such question is: does season have an effect on the occurrence of colic? Time-series analysis provides a rigorous statistical approach to this question but until now, to our knowledge, it has not been used in this context. Traditional time-series modelling approaches have limited applicability in the case of relatively rare diseases, such as specific types of equine colic. In this paper we present a modelling approach that respects the discrete nature...
Gildea S, Garvey M, Lyons P, Lyons R, Gahan J, Walsh C, Cullinane A.Equine influenza (EI) outbreaks occurred on 19 premises in Ireland during 2014. Disease affected thoroughbred (TB) and non-TB horses/ponies on a variety of premises including four racing yards. Initial clinical signs presented on 16 premises within a two-month period. Extensive field investigations were undertaken, and the diagnostic effectiveness of a TaqMan RT-PCR assay was demonstrated in regularly-vaccinated and sub-clinically-affected horses. Epidemiological data and repeat clinical samples were collected from 305 horses, of which 40% were reported as clinically affected, 39% were identif...
Browning GF, Studdert MJ.The epidemiology of equine herpesvirus 2 was examined by using restriction endonuclease DNA fingerprints to distinguish viruses isolated from two groups of horses. The first group consisted of three yearlings isolated from other horses but in contact with each other for 418 days, whereas the second comprised seven mares and their foals, which were sampled at monthly intervals from parturition until the foals were about 180 days old. There was a complex pattern of transmission, with 15 different viruses isolated from both groups. Four distinguishable viruses were isolated from the three yearlin...
Park AW, Wood JL, Daly JM, Newton JR, Glass K, Henley W, Mumford JA, Grenfell BT.We assess the effects of strain heterology (strains that are immunologically similar but not identical) on equine influenza in a vaccinated population. Using data relating to individual animals, for both homologous and heterologous vaccinees, we estimate distributions for the latent and infectious periods, quantify the risk of becoming infected in terms of the quantity of cross-reactive antibodies to a key surface protein of the virus (haemagglutinin) and estimate the probability of excreting virus (i.e. becoming infectious) given that infection has occurred. The data suggest that the infectio...
Wang T, Hu L, Liu M, Wang T, Hu X, Li Y, Liu W, Li Y, Wang Y, Ren H, Zhang W, Wang C, Li L.The equine herpesvirus type 8 (EHV-8) can cause significant economic losses in the global horses and donkey industry. The disease has been associated with abortion and respiratory symptoms. However, it is rare for a study to be reported about donkeys with neurological diseases induced by EHV-8 infection. In the present study, one 2-year-old male donkey, from a large-scale donkey farm in China, died with a severe neurological disorder. The causative agent, donkey/Shandong/10/2021 (GenBank accession: OL856098), was identified and isolated from the brain tissue of the dead donkey. Meanwhile, BALB...
Woodward A, Rash AS, Medcalf E, Bryant NA, Elton DM.Equine influenza is a major cause of respiratory infections in horses and causes widespread epidemics, despite the availability of commercial vaccines. Antigenic drift within the haemagglutinin (HA) glycoprotein is thought to play a part in vaccination breakdown. Here, we carried out a detailed investigation of the 1989 UK outbreak, using reverse genetics and site-directed mutagenesis, to determine the individual contribution of amino acid substitutions within HA. Mutations at positions 159, 189 and 227 all altered antigenicity, as measured by haemagglutination-inhibition assays. We also compa...
Boden LA, Parkin TD, Yates J, Mellor D, Kao RR.Robust demographic information is important to understanding the risk of introduction and spread of exotic diseases as well as the development of effective disease control strategies, but is often based on datasets collected for other purposes. Thus, it is important to validate, or at least cross-reference these datasets to other sources to assess whether they are being used appropriately. The aim of this study was to use horse location data collected from different contributing industry sectors ("Stakeholder horse data") to calibrate the spatial distribution of horses as indicated by owner lo...
