Disease transmission in horses refers to the spread of infectious agents such as bacteria, viruses, fungi, and parasites among equine populations. These pathogens can be transmitted through various routes, including direct contact, vector-borne transmission, or environmental exposure. Factors influencing disease transmission include horse density, management practices, and biosecurity measures. Understanding the mechanisms and conditions that facilitate the spread of diseases is essential for developing effective prevention and control strategies. This page compiles peer-reviewed research studies and scholarly articles that investigate the modes of transmission, risk factors, and management practices related to infectious diseases in horses.
El Brini Z, Cullinane A, Garvey M, Fassi Fihri O, Fellahi S, Amraoui F, Loutfi C, Sebbar G, Paillot R, Piro M.This study aimed to investigate the molecular prevalence and genetic characterization of EHV-1 and EHV-4 in equid populations in Morocco. A total of 154 equids (114 horses, 9 donkeys, and 31 mules) were sampled, with nasal swabs and tissue samples subjected to multiplex real-time PCR for the detection of EHV-1 and EHV-4. Additionally, an isolate from the tissue of an aborted horse fetus was included in the analysis. A subset of EHV-positive samples underwent virus isolation followed by whole-genome sequencing. PCR assays revealed that 42 samples (27%) tested positive for EHV-4, while only 3 sa...
Houben RMAC, van Maanen C, Newton JR, van den Broek J, Sloet van Oldruitenborgh-Oosterbaan MM, Heesterbeek JAP.Equine herpesvirus 1 (EHV-1) infection is the cause of high impact disease syndromes, affecting the global horse industry. The effect of vaccination on transmission dynamics of EHV-1 in naturally occurring outbreaks is not quantified. Our aims were to estimate R for EHV-1 in equine populations from outbreak data, and evaluate the effect of vaccination status of the herd on R through a systematic review, model-based estimations and meta-analysis. A literature search for outbreak reports was carried out. Depending on available data, the early epidemic growth rate (GR) or final attack rate (AR) a...
Cutarelli A, De Falco F, Serpe F, Izzo S, Fusco G, Catoi C, Roperto S.BPV1, BPV2, BPV13, and BPV14 are all genotypes of bovine delta papillomaviruses (δPV), of which the first three cause infections in horses and are associated with equine sarcoids. However, BPV14 infection has never been reported in equine species. In this study, we examined 58 fresh and thawed commercial semen samples from healthy stallions. In 34 (58.6%), bovine δPV DNA was detected and quantified using droplet digital polymerase chain reaction (ddPCR). Real time quantitative PCR (qPCR) was able to identify bovine δPV DNA in 5 samples (8.6%). Of the BPV-infected semen samples, 15 were posi...
Jouglin M, Bonsergent C, de la Cotte N, Mège M, Bizon C, Couroucé A, Lallemand ÉA, Leblond A, Lemonnier LC, Leroux A, Marano I, Muzard A....Equine piroplasmosis is a worldwide tick-borne disease caused by the parasites Theileria equi sensu lato and Babesia caballi, with significant economic and sanitary consequences. These two parasites are genetically variable, with a potential impact on diagnostic accuracy. Our study aimed to evaluate the frequency of asymptomatic carriers of these parasites in France and describe the circulating genotypes. We developed a species-specific nested PCR protocol targeting the 18S small sub-unit (SSU) rRNA gene and used it on blood samples collected from 566 asymptomatic horses across four National V...
Sobhy NM, Refaai W, Kumar R, Bottros Youssef CR, Goyal SM.Bovine papillomaviruses (BPVs) commonly cause sarcoids in equines worldwide. Equine sarcoids (ESs) reduce the working ability of draft animals and produce untoward cosmetic changes in racing and dancing equine. In this study, nine horses and 16 donkeys with sarcoids were presented to Zagazig University Veterinary Clinic, Zagazig, Egypt. Of these, eight horses and six donkeys were found to be infected with BPV. On sequencing, all 14 viruses were found to be BPV1, which were distributed in two clades without specific differentiation among papillomaviruses (PVs) of donkeys, horses, and cattle. Co...
Hrala M, Andrla P, Bosák J, Fedrová P, Mugutdinov A, Karpíšková R, Nedbalcová K, Raichová J, Faldyna M, Hořín P, Šmajs D.Taylorella equigenitalis is the causative agent of sexually transmitted contagious equine metritis. Infections manifest as cervicitis, vaginitis and endometritis and cause temporary infertility and miscarriages of mares. While previous studies have analyzed this organism for various parameters, the evolutionary dynamics of this pathogen, including the emergence of antibiotic resistance, remains unresolved. The aim of this study was to isolate contemporary strains, determine their genome sequences, evaluate their antibiotic resistance and compare them with other strains. We determined nine comp...
The Western equine encephalitis virus is transmitted between mosquitoes and wild birds. Mosquitoes spread the virus to horses and human populations, causing severe encephalitis and death. The most recent large outbreak occurred in South America from November 2023 to April 2024. We identified and genetically characterized Uruguayan strains during this outbreak to understand their evolutionary trends and rapid expansion. We obtained genomes from 15 strains using a novel multiplex PCR assay combined with next-generation Illumina sequencing. The phylogenetic analysis revealed that viruses from Uru...
Hermans LM, Bonsergent C, Josson A, Rocafort-Ferrer G, Le Guyader M, Angelloz-Pessey S, Leblond A, Malandrin L.Equine piroplasmosis is a tick-borne disease mainly caused by Theileria equi and Babesia caballi. The objectives of this study were to analyse the frequency and routes of vertical transmission of these blood parasites from 179 asymptomatic mares to their foals. Foals were sampled within 72 h post-partum. The seroprevalences determined by Indirect Immunofluorescent Antibody Test (IFAT) and based on a subset sample of 107 couples, were 59.8% and 42.1% for T. equi and B. caballi, respectively in the mare population, and 54.2% and 40.2% in the foal population. A species-specific nested PCR was per...
Equine infectious anemia virus (EIAV) is the simplest described within the family, related to the human immunodeficiency viruses (HIV-1 and HIV-2). There is an important interplay between host cells and viruses. Viruses need to hijack cellular proteins for their viral cycle completion and some cellular proteins are antiviral agents interfering with viral replication. HIV cellular partners have been extensively studied and described, with a special attention to host proteins able to inhibit specific steps of the viral cycle, called restriction factors. Viruses develop countermeasures against ...
Frippiat T, van den Wollenberg L, van Erck-Westergren E, van Maanen K, Votion DM.Some respiratory viruses can affect equine athletes, with acute respiratory clinical signs leading to a reduced ability to perform. The direct association between equine respiratory viruses and athletic performance is unclear in subclinically affected horses. This narrative review summarises the current evidence on respiratory viruses most commonly detected in performing horses, including equine herpesviruses, equine influenza virus, equine rhinitis viruses, equine arteritis virus, and equine adenovirus 1. It covers their virology, clinical manifestations, epidemiology, pathogenesis, diagnosis...
Public healthDecember 24, 2024
Volume 239 1-8 doi: 10.1016/j.puhe.2024.12.031
Lorenz C, de Azevedo TS, Chiaravalloti-Neto F.The Western equine encephalitis virus (WEEV) is a globally relevant vector-borne pathogen that causes encephalitis. The role of environmental variables in the epidemiology of WEEV has become greater in the context of climate change. In December 2023, a significant resurgence of WEEV began in South America, with major ongoing outbreaks in Argentina and Uruguay. In this study, we employed a machine learning algorithm to model the distribution of WEEV in South America, considering both present and future scenarios. Methods: Ecological retrospective study. Methods: We conducted a modelling study t...
Smith MZ, York M, Townsend KS, Martin LM, Gull T, Coghill LM, Ericsson AC, Johnson PJ.Whereas restoration of fecal consistency after treatment with clioquinol for chronic diarrhea and free fecal water syndrome has been attributed to its antiprotozoal properties, actions of clioquinol on the colonic bacterial microbiota have not been investigated. Objective: Characterize the dynamics of fecal microbial diversity before, during, and after PO administration of clioquinol to healthy horses. Methods: Experimental prospective cohort study using a single horse group. Methods: Eight healthy adult horses received PO clioquinol (10 g, daily) for 7 days. Feces were obtained daily for ...
Pusterla N, Lawton K, Barnum S, Ross K, Purcell K.The objective of this study was to describe an outbreak of equine herpesvirus-1 myeloencephalopathy (EHM) in a population of aged equids. The outbreak was linked to the introduction of five healthy non-resident horses 15 days prior to the first case of acute recumbency. This fulminant EHM outbreak was predisposed by the grouping of the 33 unvaccinated animals in two large pens with shared water and feed troughs. Fourteen horses (42.4%) developed neurological deficits within the first week of the outbreak. Four additional equids developed fever and respiratory signs (EHV-1 infection), while fif...
Cabete A, Xufre Â, Padre L, Bettencourt E, Nunes T, Gomes J.Equine piroplasmosis (EP) is a tick-borne disease of equids caused by Theileria equi, Theileria haneyi, and Babesia caballi. EP is endemic in most tropical and subtropical regions worldwide, and there is a likelihood that it is also endemic in Portugal. This retrospective study aimed to determine the seroprevalence, prevalence, and potential risk factors of EP in our country over the past five years. A total of 3063 diagnostic test records were analysed. Results from the competitive enzyme-linked immunosorbent assay (cELISA) revealed a seroprevalence of 32.7 % and 15.7 % for T. equi and B....
Carrasco L, Utrilla MJ, Fuentes-Romero B, Fernandez-Novo A, Martin-Maldonado B.West Nile Virus (WNV) is a zoonotic, vector-borne pathogen affecting humans and animals, particularly in Europe. The virus is primarily transmitted through mosquitoes that infect birds, which serve as the main reservoirs. Humans and horses are incidental hosts. This review focuses on the epidemiology of WNV in southern Europe, particularly its increasing prevalence. Methods included an extensive literature review and analysis of recent outbreaks. WNV is largely asymptomatic in humans, but a small percentage can develop West Nile neuroinvasive disease (WNND), leading to severe neurological symp...
McCreight KA, Barbosa LN, Odoi A, Reed P, Rajeev S.We estimated the seroprevalence in dogs, cats, and horses from Tennessee, USA, using the microscopic agglutination test (MAT) against 12 serovars. We observed seropositivity in 110 of 374 (29.4%) dogs, 21 of 170 (12.4%) cats, and 42 of 88 (47.7%) horses. The highest seroprevalence was observed for serovars Autumnalis (74.6%) in dogs, and Bratislava in cats (42.9%) and horses (95.2%). We found a significant level of potential cross-reactivity between multiple serovars tested, with highest cross-reactivity to serovar Autumnalis in dogs. seroprevalence was significantly higher in vaccinated ...
Kordowitzki P.Eastern equine encephalitis virus (EEEV) is a mosquito-transmitted alphavirus that, among humans, can cause a severe and often fatal illness. The zoonotic EEEV enzootic cycle involves a cycle of transmission between and avian hosts, frequently resulting in spillover to dead-end vertebrate hosts such as humans and horses. Interestingly, it has been described that the W132G mutation of the very low-density lipoprotein receptor (VLDLR), the receptor of EEEV, significantly enhanced the VLDLR-mediated cell attachment of EEEV. The patient's metabolism plays a pivotal role in shaping the complex lan...
Haenni M, Châtre P, Drapeau A, Cazeau G, Troncy J, François P, Madec JY.Enterobacter hormaechei is an important pathogen in humans and animals, which, in addition to its intrinsic AmpC, can acquire a wide variety of genes conferring resistances to extended-spectrum cephalosporins (ESCs) and carbapenems (CPs). In France, human clinical outbreaks of E. hormaechei resistant to ESC or carbapenem were reported. Objective: To study E. hormaechei isolates from cats and dogs (=59) as well as from horses (n = 55) presenting a non-susceptible phenotype to beta-lactams in order to determine which clones, resistance genes and plasmids are circulating in France. Methods: E. ho...
Damdinjav B, Raveendran S, Mojsiejczuk L, Ankhanbaatar U, Yang J, Sadeyen JR, Iqbal M, Perez DR, Rajao DS, Park A, Viana M, Murcia PR.Recent outbreaks of influenza A(H5N1) have affected many mammal species. We report serologic evidence of H5N1 virus infection in horses in Mongolia. Because H3N8 equine influenza virus is endemic in many countries, horses should be monitored to prevent reassortment between equine and avian influenza viruses with unknown consequences.
Nassar AFC, Chiebao DP, Fava CD, Miyashiro S, Castro V, Ogata RA, Yamamora JM, Monteiro CAS, Monteiro EJB.Glanders is a zoonotic disease of equids caused by the bacterium Burkholderia mallei, responsible for considerable economic loss. This study aimed to describe the clinical manifestations, pathological findings, and also bacteriological and molecular methods for agent detection in naturally infected animals (16 adult horses and one fetus) detected by serological survey from three glanders outbreaks. Of the 16 horses, 6 (37.5%) did not show clinical signs. After necropsy,samples of organs, lymph nodes, lesions and secretions were collectedfor histopathology, bacterial isolation, and PCR. The cli...
Padalino B, Pellegrini F, Felici M, Zappaterra M, Catella C, Cordisco M, Lorusso E, Cirone F, Pratelli A.Respiratory disorders (RDs) are a common transport-related welfare consequence in horses. This prospective study described the journeys of horses transported to two slaughterhouses in Italy, documented the prevalence of potentially RD-related pathogens, and identified possible predisposing factors. Data were recorded from arrival until 48 h after arrival and included the collection of Deep Nasopharyngeal Swabs (DNS), journey details and welfare assessment of horses (n = 155). PCR was used to quantify the presence of influenza A virus, reovirus, equine herpesvirus type 1 and 4, adenovirus, r...
Jung C, Gentil M, Müller E.The objective of the study was to investigate the age dependent occurrence of different infectious agents in foals with diarrhea. Methods: Fecal samples, which were submitted to a commercial laboratory for a PCR-profile "Foal Diarrhea Pathogens" from 01.01.2021 up to 31.12.2022 (n=144), were examined for Equine Coronavirus (ECoV), , (), toxin-encoding genes , , , and , toxin-encoding genes and , as well as Rotavirus A via PCR. Results: Pathogens could be detected in a high proportion (42.9%) of the samples. Rotavirus A was the most prevalent pathogen in the current study, followed by clos...
Axt CW, Springer A, von Luckner J, Naucke TJ, Müller E, Strube C, Schäfer I.Equine piroplasmosis (EP) is caused by (.) and (.) and is transmitted by hard ticks. Predominantly, the Mediterranean region is known as being endemic for both pathogens in Europe. However, autochthonous infections in central European countries such as Germany can no longer be ruled out due to individual case reports in horses without any stays abroad as well as the geographical expansion of the habitats of different tick species. The case reports presented underline the risk of infection for horses travelling to endemic areas and in horses imported from such areas to non-endemic countries...
Solbach V, Grabatin M, Zablotski Y, Fux R, Zerbe H, Witte TS.Contagious Equine Metritis (CEM) caused by the bacterium Taylorella equigenitalis (T. equigenitalis), is a venereal infection of equids which is of international concern to the equine breeding industry. A recent study showed a high prevalence of T. equigenitalis in Icelandic stallions when compared to stallions of other breeds also using for natural breeding. Consequently, the objectives of the present study were to investigate the prevalence of T. equigenitalis in Icelandic mares and geldings and to determine factors associated with a T. equigenitalis-positive qPCR result. In total, 361 Icela...
Suganuma K, Fujita G, Macalanda AMC, Regilme MAF, Izumida H, Inoue N, Acosta TJ.Horseflies are pests that cause discomfort from blood-sucking and disease transmission, and economic losses in the equine industry. This study evaluated the efficacy of horsecloth impregnated with icaridin in reducing horsefly attacks and deterring horseflies. Repellent activities were evaluated under three conditions: treatment 1 (no horsecloth), 2 (horsecloth without icaridin), and 3 (horsecloth impregnated with icaridin), using three native Hokkaido horses (Dosanko) and three mixed-breed horses (Dosanko and Haflinger) in July 2023 at a riding horse club in Hokkaido, Japan. Treatment 3 signi...
Alayil AL, Horwood PF, Gummow B, Picard JA, Joone CJ.Leptospira species are found worldwide, favouring tropical regions, and infect a wide range of animal species. Although renal persistence in infected individuals and excretion in urine is thought to be the primary mechanism of disease transmission, recent reports have suggested that persistence in the reproductive tract may be a feature in certain species, including the horse. The aim of this study was to investigate leptospiral infection, particularly within the reproductive tract, in healthy, non-breeding mares. Serum and endometrial swab samples were collected from 50 mares from the James C...
Matsumura R, Bannai H, Nemoto M, Higa Y, Kai I, Sasaki T, Futami K, Yoshikawa A, Fujita R, Hino M, Nagata K, Kuwata R, Kaku Y, Kobayashi D....Getah virus (GETV), belonging to the genus Alphavirus within the family Togaviridae, is a mosquito-borne virus that causes fever, rash, edema in horses, fatalities, and pregnancy disorders in pigs. It has caused occasional outbreaks in horse populations in Japan, China, and India, and the endemic areas are gradually expanding, particularly in Asia and Oceania. In this study, we isolated a new GETV strain from Culex tritaeniorhynchus mosquitoes collected in Nagasaki Prefecture, Japan, in 2022. Phylogenetic analysis demonstrated that this new strain, 22IH8, was more closely related to previous C...
Soutello RVG, Romão DS, do Carmo TA, de Favare GM, Pagnozzi FC, de Almeida Cipriano I.Helminthiasis in horse breeding stands out due to the damage caused by this infection, which is mainly controlled by anthelmintic drugs. Knowing the population dynamics of helminths in a given region is therefore essential, as environmental conditions have a major impact on the development of these parasites in pastures. The aim of this study was to assess the influence of seasonality on helminths. It was carried out between October and September of the years 2015/2016, 2018/2019 and 2021/2022. A total of 147 animals were used, 64 females and 83 males, all from the same herd. Fecal samples wer...
is a tick-borne hemoparasite that causes equine piroplasmosis. It has a significant economic impact, decreasing performance and affecting animal welfare. This study aimed to identify DNA in the blood of horses from households in the southwestern and western regions of Romania. We included 310 animals, from which blood was collected via EDTA. To test the samples for the parasite genome, we used real-time PCR and conventional PCR. The prevalence of was 5.81% (18/310) in apparently healthy horses, suggesting that this parasite is enzootic in the regions studied, although veterinarians did not...
Hain-Saunders N, Knight DR, Bruce M, Riley TV.Recent increases in community-associated Clostridioides difficile infections have highlighted the importance of monitoring toxigenic C. difficile from animal and environmental sources. We provide the complete circularized genomes of two toxigenic C. difficile strains isolated from feral horse faeces. Genome N64 (sequence type 964) consists of a single chromosome of 4,078,791 bp, while genome H251 (sequence type 963) comprises one chromosome (4,304,722 bp) and three plasmids (150,942 bp, 11,534 bp, and 9,074 bp).
Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging problem in horses; however, the epidemiology of infection and colonization is poorly understood. This study evaluated factors associated with MRSA colonization at the time of admission to a veterinary teaching hospital. A case-control study evaluating historical factors was performed. Previous colonization of the horse, previous identification of colonized horses on the farm, antimicrobial administration within 30 days, admission to the neonatal intensive care unit, and admission to a service other than the surgical service were...
Espinoza JR, Terashima A, Herrera-Velit P, Marcos LA.Fasciola hepatica is the causative agent of fasciolosis in Peru; the disease is an important public health problem by the high prevalence of the human infection affecting mainly children and a major veterinary problem by the high rates of infected livestock. The human disease is endemic in the Sierra and the Coast but sporadic in the Amazonia, and reported in 18 Departments, while the animal infection in 21 of 24 Departments of Peru. Transmission occurs in Andean rural populations engaged in agriculture, but recently an increasing number of people became infected in the cities. The epidemiolog...
de Paula LGF, do Nascimento RM, Franco AO, Szabó MPJ, Labruna MB, Monteiro C, Krawczak FDS.Amblyomma sculptum is a hard tick that is associated with domestic animals and the transmission of Brazilian spotted fever. This association has motivated several field studies on this ixodid tick within its distribution area in South America. Thorough knowledge of the seasonal dynamics of A. sculptum in different ecological scenarios is required in order to better understand the biological characteristics of this tick and develop techniques for the control and prevention of diseases transmitted by this vector. In this article, we systematically review the seasonal dynamics of A. sculptum and ...
Cordeiro Rde A, de Oliveira JS, Castelo-Branco Dde S, Teixeira CE, Marques FJ, Bittencourt PV, Carvalho VL, Bandeira Tde J, Brilhante RS, Moreira JL....Candida tropicalis has been associated with invasive candidiasis, being the first or second most common non-Candida albicans Candida species isolated in humans with candidemia and candiduria, as well as being frequently isolated from healthy animals. This study aimed to characterize C. tropicalis isolates (n = 64) obtained from several animal species regarding antifungal susceptibility and production of virulence factors. The isolates were obtained from the microbiota of healthy animals (goats, n = 25; sheep, n = 6; psittacines, n = 14; rheas, n = 6; horses, n = 2; sirenians, n = 5; shrimp, n ...
Young JJ, Coulombier D, Domanović D, Zeller H, Gossner CM.West Nile virus (WNV) infection is notifiable in humans and equids in the European Union (EU). An area where a human case is detected is considered affected until the end of the mosquito transmission season (week 48) and blood safety measures have to be implemented. We used human and equine case notifications between 2013 and 2017 to define the WNV distribution in the EU and to investigate the relevance of using equine cases as a complementary trigger for blood safety measures. Adding areas with equine cases to the definition of an affected area would have a major impact on blood safety measur...
Vittecoq M, Lecollinet S, Jourdain E, Thomas F, Blanchon T, Arnal A, Lowenski S, Gauthier-Clerc M.In recent years, the number of West Nile virus (WNV) cases reported in horses and humans has increased dramatically throughout the Mediterranean basin. Furthermore, the emergence of Usutu virus (USUV) in Austria in 2001, and its subsequent expansion to Hungary, Spain, Italy, Switzerland, the United Kingdom, and Germany, has given added cause for concern regarding the impact of the spread of flaviviruses on human and animal health in western Europe. Despite frequent detection of WNV and USUV cases in neighboring countries, no case of WNV has been detected in France since 2006 and USUV has never...
Kaspar U, von Lützau K, Schlattmann A, Rösler U, Köck R, Becker K.Colonization with multidrug-resistant organisms (MDROs) belonging to the genus Staphylococcus and the order Enterobacterales poses a particular threat to populations at risk. While previous studies focused on MDRO carriage among livestock or companion animals, respective epidemiological data on the general equine population are limited. Here, carriage of methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum beta-lactamase (ESBL) producing Enterobacteriaceae (ESBL-E) in non-hospitalized horses living on private farms in the rural area in Northwest Germany was assessed. Intran...
Zolzaya B, Selenge T, Narangarav T, Gantsetseg D, Erdenechimeg D, Zinsstag J, Schelling E.Mongolia implemented a brucellosis livestock mass vaccination campaign from 2000 to 2009. However, the number of human cases did not decline since 2004 and the current epidemiological situation in Mongolia was uncertain. The objective of this study was to estimate the representative seroprevalences of humans and livestock in two provinces in view of their comparison with officially reported data. A representative cross-sectional study using cluster sampling proportional to size in humans, sheep, goats, cattle, yaks, horses, camels and dogs was undertaken to assess the apparent seroprevalence i...
Wilson WD.Myeloencephalopathy is an uncommon manifestation of equine herpesvirus 1 (EHV-1), but it can cause devastating losses during outbreaks on individual farms. Clinical signs of neurologic disease reflect a diffuse multifocal hemorrhagic myeloencephalopathy secondary to vasculitis and thrombosis. Sudden onset and early stabilization of signs, including ataxia, paresis, and urinary incontinence; involvement of multiple horses on the premises; and recent history of fever, abortion, or viral respiratory disease in the affected horse or herdmates are typical features, although there is considerable va...
Gilkerson JR, Whalley JM, Drummer HE, Studdert MJ, Love DN.The prevalence of EHV-1 and EHV-4 antibody-positive horses was determined using a type specific ELISA on serum samples collected from 229 mares and their foals resident on a large Thoroughbred stud farm in the Hunter Valley of New South Wales in February 1995. More than 99% of all mares and foals tested were EHV-4 antibody positive, while the prevalence of EHV-1 antibody positive mares and foals were 26.2 and 11.4%, respectively. Examination of the ELISA absorbance data for the individual mares and foals suggested that the EHV-1 antibody positive foals had been infected recently with EHV-1 and...
Riet-Correa F, Rivero R, Odriozola E, Adrien Mde L, Medeiros RM, Schild AL.In the current study, mycotoxicoses of ruminants and horses are reviewed, with an emphasis on the occurrence of these diseases in South America. The main mycotoxicoses observed in grazing cattle include intoxications by indole-diterpenoid mycotoxins (Paspalum spp. contaminated by Claviceps paspali, Lolium perenne infected by Neotyphodium lolii, Cynodon dactylon infected by Claviceps cynodontis, and Poa huecu), gangrenous ergotism and dysthermic syndrome (hyperthermia) caused by Festuca arundinacea (syn. Festuca elatior) infected by Neotyphodium coenophialum (syn. Acremonium coenophialum), and ...
Nielsen MK, Banahan M, Kaplan RM.Anthelmintic resistance in equine cyathostomins is both widespread and highly prevalent in the benzimidazole and tetrahydropyrimidine classes; however, reports of resistance to macrocyclic lactone (ML) drugs are sparse and sporadic. This study reports a case of clear ML resistance in a group of Thoroughbred yearlings imported from Ireland to the US in 2019. Fecal egg count reduction (FECR) following ivermectin administered in February 2020 demonstrated 100% reduction in the US bred yearlings, but 93.5%, 70.5%, and 74.5% reduction in three groups of the imported yearlings. The two former groups...
Dayaram A, Franz M, Schattschneider A, Damiani AM, Bischofberger S, Osterrieder N, Greenwood AD.For viruses to utilize environmental vectors (hard surfaces, soil, water) for transmission, physical and chemical stability is a prerequisite. There are many factors including pH, salinity, temperature, and turbidity that are known to contribute to the ability of viruses to persist in water. Equine herpesvirus type-1 (EHV-1) is a pathogenic alphaherpesvirus associated with domestic horses and wild equids. EHV-1 and recombinants of EHV-1 and EHV-9 are able to cause infections in non-equid animal species, particularly in captive settings. Many of the captive non-equid mammals are not naturally s...
Issel CJ, Foil LD.There are several factors involved in the mechanical transmission of equine infectious anemia (EIA) virus by insects. Large hematophagous insects, especially tabanids, which feed from extravascular sites (ie, pool feeding) appear to be the most efficient vectors. The biology of the host-seeking and blood-feeding behavior of the vectors are important variables that have been overlooked in the mechanical transmission of pathogens like EIA virus. The biology, population levels, and diversity of the vectors, in addition to the clinical status and proximity of EIA virus-infected horses maintained w...
Ulbert S.West Nile virus (WNV) is a zoonotic virus that circulates in birds and is transmitted by mosquitoes. Incidentally, humans, horses and other mammals can also be infected. Disease symptoms caused by WNV range from fever to neurological complications, such as encephalitis or meningitis. Mortality is observed mostly in older and immunocompromised individuals. In recent years, epidemics caused by WNV in humans and horses have become more frequent in several Southern European countries, such as Italy and Greece. In 1999, WNV was introduced into the USA and spread over North America within a couple o...
Seo MG, Lee SH, Ouh IO, Lee GH, Goo YK, Kim S, Kwon OD, Kwak D.Members of the genus Coxiella can be transmitted from ticks to humans during contact with animals; Coxiella may thus spread from the infected horses or ticks to humans. In this study, the presence of Coxiella burnetii and Coxiella-like endosymbionts (CLE) in ticks found on infested horses was determined using PCR and genotyping. A total of 213 ticks were randomly collected from 51 horses (4-5 ticks per horse) raised on Jeju Island, Korea, between 2009 and 2013. All ticks were morphologically identified as adult Haemaphysalis longicornis, a predominant tick species widespread in Korea. Based on...
Hoet AE, Johnson A, Nava-Hoet RC, Bateman S, Hillier A, Dyce J, Gebreyes WA, Wittum TE.Concurrent to reports of zoonotic and nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary settings, recent evidence indicates that the environment in veterinary hospitals may be a potential source of MRSA. The present report is a cross-sectional study to determine the prevalence of MRSA on specific human and animal contact surfaces at a large veterinary hospital during a nonoutbreak period. A total of 156 samples were collected using Swiffers(®) or premoistened swabs from the small animal, equine, and food animal sections. MRSA was isolated and identifi...
Guidi E, Pradier S, Lebert I, Leblond A.Theileria equi (Laveran 1901) and Babesia caballi (Nuttall and Strickland 1910) are the causative agents of Equine Piroplasmosis (EP), a severe and problematic disease compromising international movement of horses. Infected horses usually become asymptomatic carriers and, for this reason, their movement across borders may become restricted. The aim of this study was to assess the seroprevalence of EP in Southern France and to evaluate risk factors associated with these parasites. In 2002, we performed a complement fixation test (CF) with blood samples from 443 horses stabled at 95 different fa...
Armstrong PM, Andreadis TG.In the current review, we examine the regional history, ecology, and epidemiology of eastern equine encephalitis virus (EEEV) to investigate the major drivers of disease outbreaks in the northeastern United States. EEEV was first recognized as a public health threat during an outbreak in eastern Massachusetts in 1938, but historical evidence for equine epizootics date back to the 1800s. Since then, sporadic disease outbreaks have reoccurred in the Northeast with increasing frequency and northward expansion of human cases during the last 20 yr. Culiseta melanura (Coquillett) (Diptera: Culicidae...
Martella V, Elia G, Decaro N, Di Trani L, Lorusso E, Campolo M, Desario C, Parisi A, Cavaliere N, Buonavoglia C.In December 2005, equine influenza virus infection was confirmed as the cause of clinical respiratory disease in vaccinated horses in Apulia, Italy. The infected horses had been vaccinated with a vaccine that contained strains representatives from both the European (A/eq/Suffolk/89) and American (A/eq/Newmarket/1/93) H3N8 influenza virus lineages, and the H7N7 strain A/eq/Praga/56. Genetic characterization of the hemagglutinin (HA) and neuraminidase (NA) genes of the virus from the outbreak, indicated that the isolate (A/eq/Bari/2005) was an H3N8 strain closely related to recent representative...
Crans WJ, Caccamise DF, McNelly JR.Eastern equine encephalomyelitis virus (EEEV) is perpetuated in eastern North America in a mosquito-wild bird maintenance cycle that involves Culiseta melanura (Coquillett) as the principal enzootic vector and passerine birds as the primary amplifying hosts. We examined the role of birds in the EEEV cycle at a site in southern New Jersey where EEEV cycles annually at high levels. Birds and mosquitoes were sampled during three epiornitics and one season of limited virus activity. We examined antibody prevalence in birds in relation to eight physical and natural history characteristics. Our goal...
Firestone SM, Cogger N, Ward MP, Toribio JA, Moloney BJ, Dhand NK.The influences of relative humidity and ambient temperature on the transmission of influenza A viruses have recently been established under controlled laboratory conditions. The interplay of meteorological factors during an actual influenza epidemic is less clear, and research into the contribution of wind to epidemic spread is scarce. By applying geostatistics and survival analysis to data from a large outbreak of equine influenza (A/H3N8), we quantified the association between hazard of infection and air temperature, relative humidity, rainfall, and wind velocity, whilst controlling for prem...
Isgren CM, Edwards T, Pinchbeck GL, Winward E, Adams ER, Norton P, Timofte D, Maddox TW, Clegg PD, Williams NJ.This study investigated changes over time in the epidemiology of extended-spectrum β-lactamase (ESBL) producing Escherichia coli within a single equine referral hospital in the UK. Faecal samples were collected from hospitalised horses in 2008 and 2017, processed using selective media and standard susceptibility laboratory methods. A novel real-time PCR with high resolution melt analysis was used to distinguish bla and bla within CTX-M-1 group. Results: In 2008, 457 faecal samples from 103 horses were collected, with ESBL-producing E. coli identified in 131 samples (28.7, 95% CI 24.6-33.1). I...
Martin G, Plowright R, Chen C, Kault D, Selleck P, Skerratt LF.Hendra virus (HeV) is lethal to humans and horses, and little is known about its epidemiology. Biosecurity restrictions impede advances, particularly on understanding pathways of transmission. Quantifying the environmental survival of HeV can be used for making decisions and to infer transmission pathways. We estimated HeV survival with a Weibull distribution and calculated parameters from data generated in laboratory experiments. HeV survival rates based on air temperatures 24 h after excretion ranged from 2 to 10 % in summer and from 12 to 33 % in winter. Simulated survival across the distri...
Dhondt KP, Horvat B.The Henipavirus genus contains two highly lethal viruses, the Hendra and Nipah viruses and one, recently discovered, apparently nonpathogenic member; Cedar virus. These three, negative-sense single-stranded RNA viruses, are hosted by fruit bats and use EphrinB2 receptors for entry into cells. The Hendra and Nipah viruses are zoonotic pathogens that emerged in the middle of 90s and have caused severe, and often fatal, neurologic and/or respiratory diseases in both humans and different animals; including spillover into equine and porcine species. Development of relevant models is critical for a ...
West Nile virus (WNV) is a member of the Japanese encephalitis serocomplex, which was first described in 1937 as neurotropic virus in Uganda in 1937. Subsequently, WNV was identified in the rest of the old-world and from 1999 in North America. Birds are the primary hosts, and WNV is maintained in a bird-mosquito-bird cycle, with pigs as amplifying hosts and humans and horses as incidental hosts. WNV transmission is warranted by mosquitoes, usually of the spp., with a tendency to spill over when mosquitoes' populations build up. Other types of transmissions have been described in endemic areas...
Wild TF.Paramyxoviruses have been implicated in both animal and human infections. Some viruses, such as Morbilliviruses are responsible for large-scale epidemics. However, there are limited observations of these viruses crossing the host species barrier in nature. In 1994, in Australia a fatal infection in horses and humans was identified to be caused by a new Paramyxovirus, Hendra virus (HeV), and in 1998 in Malaysia, a closely related virus, Nipah virus (NiV) was responsible for fatal infections in pigs and humans. These two viruses were sufficiently different from previously described Paramyxovirus...
Adams AP, Navarro-Lopez R, Ramirez-Aguilar FJ, Lopez-Gonzalez I, Leal G, Flores-Mayorga JM, Travassos da Rosa AP, Saxton-Shaw KD, Singh AJ....Venezuelan equine encephalitis virus (VEEV) has been the causative agent for sporadic epidemics and equine epizootics throughout the Americas since the 1930s. In 1969, an outbreak of Venezuelan equine encephalitis (VEE) spread rapidly from Guatemala and through the Gulf Coast region of Mexico, reaching Texas in 1971. Since this outbreak, there have been very few studies to determine the northward extent of endemic VEEV in this region. This study reports the findings of serologic surveillance in the Gulf Coast region of Mexico from 2003-2010. Phylogenetic analysis was also performed on viral is...
Walther B, Klein KS, Barton AK, Semmler T, Huber C, Merle R, Tedin K, Mitrach F, Lübke-Becker A, Gehlen H.Continuing introduction of multi-drug resistant, zoonotic pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) in horse clinics challenges the biosafety of employees and animal patients. This study was aimed to determine the occurrence of mobile genetic elements facilitating survival in the early stages of invasive infection in different host species, including humans and horses, in MRSA carried by equine patients admitted to a large horse clinic. A total of 341 equine patients were investigated for carriage of MRSA by hygiene screening directly at hospital admission. MRSA were...
Matsuo K, Kamai R, Uetsu H, Goto H, Takashima Y, Nagamune K.The presence of antibodies to Toxoplasma gondii in livestock and poultry was investigated by latex agglutination tests; samples that agglutinated at dilutions of 1:64 or higher were regarded as positive. Sera were collected from fattening beef cattle (102 Japanese black, 105 crossbreeds and 114 castrated Holstein), culled dairy cattle (101 Holstein), 100 horses, 115 fattening pigs and 235 chickens (163 free-range and 72 broilers) at abattoirs in Gifu Prefecture, Japan, from August 2012 to August 2013. Antibodies to T. gondii were found in 7.3% (31/422) in cattle, 5.2% (8/155) in pigs, but not ...
