Emelogu U, Lewin AC, Balasuriya UBR, Liu CC, Wilkes RP, Zhang J, Mills EP, Carter RT.Equid alphaherpesvirus 1 (EHV-1) is a global viral pathogen of domestic equids which causes reproductive, respiratory and neurological disease. Few isolates acquired from naturally infected USA-based hosts have been fully sequenced and analyzed to date. An ORF 30 (DNA polymerase) variant (A2254G) has previously been associated with neurological disease in host animals. The purpose of this study was to perform phylogenomic analysis of EHV-1 isolates acquired from USA-based hosts and compare these isolates to previously sequenced global isolates. Methods: EHV-1 was isolated from 23 naturally inf...
Kawanishi N, Kinoshita Y, Kambayashi Y, Bannai H, Tsujimura K, Yamanaka T, Cullinane A, Nemoto M.Equine influenza virus (EIV) infection is one of the most important respiratory diseases in the equine industry around the world. Rapid diagnosis, facilitated by point-of-care testing, is essential to implement movement restrictions and control disease outbreaks. This study evaluated a microfluidic immunofluorescence assay kit, which detects influenza virus and SARS-CoV-2 antigens in human specimens with a 12 min turnaround time, for its potential use in detecting EIV. The microfluidic immunofluorescence assay kit succeeded in detecting 11 EIV strains. Using the real-time reverse transcription...
Madrigal-Valencia TL, Saavedra-Montau00f1ez M, Pu00e9rez-Torres A, Hernu00e1ndez J, Segalu00e9s J, Hernu00e1ndez YD, Candanosa-Aranda IE....Ovine gammaherpesvirus 2 (OvHV-2), a member of the genus Macavirus, causes sheep-associated malignant catarrhal fever (SA-MCF), a fatal lymphoproliferative disease affecting a wide variety of ungulates in addition to horses. This study described an outbreak of SA-MCF in Mexico and the identification of the OvHV-2 virus in primary rabbit testis cultures through the generation of intranuclear inclusion bodies, syncytia, immunofluorescence (IF), immunocytochemistry (ICC), immunohistochemistry (IHC), endpoint polymerase chain reaction (PCR), and partial sequencing of the ORF75 gene. The animals in...
Virtanen J, Hautaniemi M, Dutra L, Plyusnin I, Hautala K, Smura T, Vapalahti O, Sironen T, Kant R, Kinnunen PM.We report a sequencing protocol and 121-kb poxvirus sequence from a clinical sample from a horse in Finland with dermatitis. Based on phylogenetic analyses, the virus is a novel parapoxvirus associated with a recent epidemic; previous data suggest zoonotic potential. Increased awareness of this virus and specific diagnostic protocols are needed.
Rockx B, Mire CE.Henipaviruses are emerging zoonotic viruses that can cause outbreaks of severe respiratory and neurological disease in humans and animals such as horses. The mechanism by which these viruses can cause disease remain largely unknown and to date there are no therapeutics or vaccines approved for use in humans. Nipah virus is listed on the World Health Organization R & D Blueprint list of epidemic threats. In order to advance the availability of effective therapeutics and vaccines and medicines that can be used to save lives and avert large scale crises, animal models are required which recap...
Knox A, Zerna G, Beddoe T.Horses play an important role throughout the world, whether for work, culture, or leisure, providing an ever-growing significant contribution to the economy. The increase in importation and movement of horses, both nationally and internationally, has inevitably allowed for the global equine industry to grow. Subsequently, however, the potential for transmission of fatal equine bacterial diseases has also escalated, and devasting outbreaks continue to occur. To prevent such events, disease surveillance and diagnosis must be heightened throughout the industry. Current common, or "gold-standard" ...
Bennet ED, Parkin TDH.Racehorse training and racing schedules in many parts of the United States and Canada were interrupted or otherwise reduced during the first three to six months of 2020. This was an indirect consequence of mitigations to prevent the spread of the pandemic virus COVID-19. Data from the Equine Injury Database, a census-level survey of all race starts made in the USA and Canada, were used to analyse the incidence of fatalities in 2009-2022 among three age cohorts of racehorses within each year. There was a statistically significant increase in the incidence of musculoskeletal fatalities among 2-y...
Levasseur A, Arsenault J, Paru00e9 J.West Nile virus (WNV) became notifiable in horses in 2003 in Canada and has been reported every year since. The objective of this study was to describe the spatiotemporal distribution of WNV in horses between 2003 and 2020 in Canada. Methods: The 848 symptomatic and laboratory-confirmed WNV cases in horses reported to the Canadian Food Inspection Agency between 2003 and 2020. Methods: Canada was divided into eastern and western regions for analysis. For each case, location and date of notification were captured. Triennial maps were made to describe the spatiotemporal distribution and expansion...
El-Hage C, Legione A, Devlin J, Hughes K, Jenkins C, Gilkerson J. is an important zoonotic pathogen. Although primarily a pathogen of birds, from which infection can spillover into humans and other mammalian hosts, the importance of as a cause of equine reproductive loss and the risk of infection to humans in contact with infected horses are increasingly being recognised in Australia and elsewhere. Despite the risks to both human and equine health, infection in horses is incompletely understood. This study aimed to update and summarise cases of equine psittacosis in Australia in the period 2018-2022, thus addressing a knowledge gap relating to recent case...
Li H, Kim JV, Pickering BS.Hendra virus (HeV) and Nipah virus (NiV) are biosafety level 4 zoonotic pathogens causing severe and often fatal neurological and respiratory disease. These agents have been recognized by the World Health Organization as top priority pathogens expected to result in severe future outbreaks. HeV has caused sporadic infections in horses and a small number of human cases in Australia since 1994. The NiV Malaysia genotype (NiV-M) was responsible for the 1998-1999 epizootic outbreak in pigs with spillover to humans in Malaysia and Singapore. Since 2001, the NiV Bangladesh genotype (NiV-B) has been t...
Sewgobind S, McCracken F, Schilling M.West Nile virus (WNV) is a positive-sense single-stranded RNA virus belonging to the Flaviviridae family and is maintained in an enzootic cycle between avian hosts and mosquito vectors. Humans, horses and other mammals are susceptible to infection but are dead-end hosts due to a low viraemia. The disease can manifest itself in a variety of clinical signs and symptoms in people and horses from mild fever to severe encephalitis and morbidity. There are no vaccines licensed for human protection, but parts of Europe, North America, Africa and Australia have vaccines commercially available for hors...
Gonzálvez M, Franco JJ, Barbero-Moyano J, Caballero-Gómez J, Ruano MJ, Martínez R, Cano-Terriza D, García-Bocanegra I.The largest epidemic of West Nile virus (WNV) reported ever in Spain in both humans and equines occurred in 2020, affecting 77 humans and 139 equine herds. Here, we aimed to monitor the outbreaks detected in equid herds in Andalusia (southern Spain), the Spanish region where 89.9% of the outbreaks were reported, and to evaluate the virus circulation and risk factor associated with WNV exposure in the affected herds. The first WNV case was detected in mid-July 2020, the number of outbreaks peaked in mid-August and the last one was confirmed on 26th October 2020. WNV lineage 1 was detected in 12...
Langsjoen RM, Key A, Shariatzadeh N, Jackson CR, Mahmood F, Arkun K, Alexandrescu S, Solomon IH, Piantadosi A.Eastern equine encephalitis virus (EEEV) is a relatively little-studied alphavirus that can cause devastating viral encephalitis, potentially leading to severe neurological sequelae or death. Although case numbers have historically been low, outbreaks have been increasing in frequency and scale since the 2000 s. It is critical to investigate EEEV evolutionary patterns, especially within human hosts, to understand patterns of emergence, host adaptation, and within-host evolution. To this end, we obtained formalin-fixed paraffin-embedded tissue blocks from discrete brain regions from five contem...
Nielsen MK.Anoplocephalid tapeworms are commonly occurring in grazing horses around the world. Two currently available anthelmintics have documented high efficacy against Anoplocephala perfoliata; praziquantel in various dosages ranging from 1.0 to 2.5 mg/kg and pyrantel pamoate administered at 13.2 mg base/kg. Anthelmintic resistance has not been reported in A. perfoliata, but anecdotal reports made during 2022 have suggested a possible loss of efficacy for both actives. This paper reports fecal egg count data from a Thoroughbred operation in Central Kentucky in 2023. Fifty-six yearlings were first de...
Nielsen MK, Leathwick DM, Sauermann CW.Over the past three decades, equine strongylid egg reappearance periods (ERPs) have shortened substantially for macrocyclic lactone anthelmintics. The ERPs of ivermectin and moxidectin were originally reported in the 8-10 and 12-16 week ranges, respectively, but several recent studies have found them to be around 4-5 weeks for both actives. This loss of several weeks of suppressed strongylid egg output could have substantial implications for parasite control. This study made use of a computer simulation model to evaluate the impact of shortened ERPs on the anthelmintic performance of ivermecti...
Azhar M, Gadahi JA, Bhutto B, Tunio S, Vistro WA, Tunio H, Bhutto S, Ram T.Babesiosis is a protozoal disease affect livestock and pet animals such as cattle, buffaloes, sheep, goats, horses, donkeys, mules, dogs, and cats. It causes severe economic losses in livestock as well as in pet animals. A large number of dairy animals are imported in order to fulfill the demands of milk, milk, meat and its products. In addition, different pet animals are transported from Pakistan to various parts of the world, therefore, it is important to identify the current status and distribution of babesiosis throughout Pakistan in order to control the disease and draw attention for futu...
Couroucu00e9 A, Normand C, Tessier C, Pomares R, Thu00e9venot J, Marcillaud-Pitel C, Legrand L, Pitel PH, Pronost S, Lupo C.A total of 752 horses were involved in the CES Valencia Spring Tour 2021. Due to an equine herpesvirus-1 (EHV-1) outbreak, the competition was cancelled and the site was locked down. The objective of this study was to describe epidemiological, clinical, diagnostic, and outcome data of the 160 horses remaining in Valencia. Clinical and quantitative polymerase chain reaction (qPCR) data were analysed for 60 horses in a retrospective case-control observational study. The risk of developing clinical manifestations was explored using a logistic regression approach. EHV-1 was detected by qPCR, genot...
Gysens L, Vanmechelen B, Maes P, Martens A, Haspeslagh M.Infection with bovine papillomavirus (BPV) types 1 and 2 results in the most common skin tumor of horses, termed equine sarcoid. The persistent and recurrent nature of this tumor stands in contrast to the regressive nature of BPV-1/- 2 induced cutaneous papillomas in cattle. The circulation of horse-specific BPV-1/- 2 variants within equine populations has been suggested as a possible explanation for the difference in clinical presentation of BPV-1/- 2 infection between horses and cattle. In order to investigate this hypothesis, we identified 98 complete BPV-1/- 2 genomes using a Nanopore ...
Hill V, Koch RT, Bialosuknia SM, Ngo K, Zink SD, Koetzner CA, Maffei JG, Dupuis AP, Backenson PB, Oliver J, Bransfield AB, Misencik MJ, Petruff TA....Eastern equine encephalitis virus (EEEV) causes a rare but severe disease in horses and humans and is maintained in an enzootic transmission cycle between songbirds and Culiseta melanura mosquitoes. In 2019, the largest EEEV outbreak in the United States for more than 50 years occurred, centered in the Northeast. To explore the dynamics of the outbreak, we sequenced 80 isolates of EEEV and combined them with existing genomic data. We found that, similar to previous years, cases were driven by multiple independent but short-lived virus introductions into the Northeast from Florida. Once in the ...
Saklou N, Pleasant S, Lahmers K, Funk R.Equine Herpesvirus type 1 (EHV-1) typically causes mild respiratory disease, but it can also cause late-term abortion, neonatal foal death and neurologic disease. Once a horse is infected, the virus concentrates to local lymphoid tissue, where it becomes latent. The virus can be reactivated during times of stress, which can lead to the initiation of devastating outbreaks. Understanding the carriage rate of latent EHV-1 in different geographic regions is essential for managing the disease. The objective of the current study was to estimate the prevalence of latent EHV-1 and compare the frequenc...
Adam E.Emma Adam of the Gluck Equine Research Center at the University of Kentucky in the USA provides an update on rotaviruses, particularly the group B equine rotavirus identified in 2021.
Gillen A, Catherine Archer D.Epidemiologic studies are essential for the generation of evidence-based, preventive health care strategies. This includes ways to minimize colic risk and assist informed decision making concerning diagnosis, treatment, and likely outcomes. It is important to consider that colic is not a simple "disease" but is a syndrome of abdominal pain that encompasses multiple different disease processes, and which is multifactorial in nature. This review focuses on prevention and diagnosis of colic, including specific forms of colic, communications with owners/carers concerning colic risk and management,...
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...
Kozytska T, Bassiouny M, Chechet O, Ordynska D, Galante D, Neubauer H, Wareth G.Anthrax is an acute infectious zoonotic disease caused by that mostly affects grazing livestock and wildlife. Furthermore, is considered one of the most important biological agents of bioterrorism that could also be potentially misused in biological weapons. The distribution of anthrax in domestic animals and wildlife in Europe with a particular focus on Ukraine as a country of war was analyzed. Between 2005 and 2022, 267 anthrax cases were registered at the World Organization of Animal Health (WOAH) in animals in Europe, including 251 cases in domestic animals and 16 in wildlife. The highes...
Mendes Junior AAV, Filgueira CPB, Miranda LFC, de Almeida AB, Cantanhu00eade LM, Fagundes A, Pereira SA, Menezes RC, Cupolillo E.Epidemiological data related to leishmaniases or Leishmania infection in horses are scarce. However, studies carried out in different regions in the world showed equids parasitised by Leishmania braziliensis, L. infantum and L. martiniquensis. Objective: Identify the Leishmania species causing cutaneous leishmaniasis in a mare, living in Rio de Janeiro State (Brazil), and search the presence of Leishmania viruses in the isolated parasite. Methods: Isoenzymes and polymerase chain reaction (PCR) targeting ITSrDNA region followed by sequencing were conducted for typing the isolated parasite. A se...
Kamyingkird K, Choocherd S, Chimnoi W, Klinkaew N, Kengradomkij C, Phoosangwalthong P, Thammasonthijarern N, Pattanatanang K, Inpankaew T, Phasuk J....African horse sickness (AHS) was reported as an outbreak in Thailand in 2020. Hematophagous insects from the genus are the suspected vector responsible for AHS transmission. Horses in Hua Hin district, Prachuab Khiri Khan province, Thailand, were affected and died from AHS in 2020. However, the potential species and its host preference blood meal in the affected areas are unknown. To investigate the potential vectors of AHS, were collected using ultraviolet light traps placed near horse stables. Six horse farms, including five farms with AHS history and one farm without AHS history, were in...
Berman N, Tirosh-Levy S, Steinman A, Minderigiu A, Blinder E, Leszkowicz Mazuz M. is a tissue cyst forming coccidia, which affects multiple host species worldwide. Equine besnoitiosis is characterized mainly by generalized skin lesions and cysts in the scleral conjunctiva. Recent reports revealed exposure to in equines in Europe and the United States. However, the exposure to spp. in the Israeli equine population was never investigated. The aim of this study was to evaluate the seroprevalence and associated risk factors for besnoitiosis in equids in Israel. A cross-sectional serosurvey was performed using serum samples of apparently healthy horses ( = 347), donkeys ( = 9...
Pellegrini F, Buonavoglia A, Omar AH, Diakoudi G, Lucente MS, Odigie AE, Sposato A, Augelli R, Camero M, Decaro N, Elia G, Bu00e1nyai K, Martella V....Massive sequencing techniques have allowed us to develop straightforward approaches for the whole genome sequencing of viruses, including influenza viruses, generating information that is useful for improving the levels and dimensions of data analysis, even for archival samples. Using the Nanopore platform, we determined the whole genome sequence of an H3N8 equine influenza virus, identified from a 2005 outbreak in Apulia, Italy, whose origin had remained epidemiologically unexplained. The virus was tightly related (>99% at the nucleotide level) in all the genome segments to viruses identif...
Murray K, Selleck P, Hooper P, Hyatt A, Gould A, Gleeson L, Westbury H, Hiley L, Selvey L, Rodwell B.A morbillivirus has been isolated and added to an increasing list of emerging viral diseases. This virus caused an outbreak of fatal respiratory disease in horses and humans. Genetic analyses show it to be only distantly related to the classic morbilliviruses rinderpest, measles, and canine distemper. When seen by electron microscopy, viruses had 10- and 18-nanometer surface projections that gave them a "double-fringed" appearance. The virus induced syncytia that developed in the endothelium of blood vessels, particularly the lungs.
Weaver SC, Ferro C, Barrera R, Boshell J, Navarro JC.Venezuelan equine encephalitis virus (VEEV) remains a naturally emerging disease threat as well as a highly developed biological weapon. Recently, progress has been made in understanding the complex ecological and viral genetic mechanisms that coincide in time and space to generate outbreaks. Enzootic, equine avirulent, serotype ID VEEV strains appear to alter their serotype to IAB or IC, and their vertebrate and mosquito host range, to mediate repeated VEE emergence via mutations in the E2 envelope glycoprotein that represent convergent evolution. Adaptation to equines results in highly effic...
Plowright RK, Foley P, Field HE, Dobson AP, Foley JE, Eby P, Daszak P.Anthropogenic environmental change is often implicated in the emergence of new zoonoses from wildlife; however, there is little mechanistic understanding of these causal links. Here, we examine the transmission dynamics of an emerging zoonotic paramyxovirus, Hendra virus (HeV), in its endemic host, Australian Pteropus bats (fruit bats or flying foxes). HeV is a biosecurity level 4 (BSL-4) pathogen, with a high case-fatality rate in humans and horses. With models parametrized from field and laboratory data, we explore a set of probable contributory mechanisms that explain the spatial and tempor...
In the last 30 years several cases of West Nile (WN) virus infection were reported in horses and humans in Europe and in the Mediterranean Basin. Most of them were determined by strains of the Lineage 1 included in the European Mediterranean/Kenyan cluster. Strains of this cluster are characterised by a moderate pathogenicity for horses and humans and limited or no pathogenicity for birds. In recent years, however, WN cases determined by strains grouped in the Israeli/American cluster of Lineage 1 or in the lineage 2 have been reported in Hungary and Austria. The role of migrating birds in int...
Zeller HG, Schuffenecker I.West Nile (WN) virus is a mosquito-transmitted flavivirus. It is widely distributed in Africa, the Middle East, Asia, and southern Europe and was recently introduced to North America. Birds are involved in the cycle of transmission as amplifying hosts. Humans and horses are considered accidental dead-end hosts. WN fever was initially considered a minor arbovirosis, usually inducing a nonsymptomatic or a mild flu-like illness in humans, but some cases of encephalitis associated with fatalities were reported in Israel in the 1950s. After two silent decades, several human and equine outbreaks of ...
Selvey LA, Wells RM, McCormack JG, Ansford AJ, Murray K, Rogers RJ, Lavercombe PS, Selleck P, Sheridan JW.To describe the clinical and epidemiological features of an outbreak of a viral infection affecting humans and horses. Methods: Stables in Hendra, a suburb of Brisbane. Methods: Affected horses and humans, and at-risk human contacts. Results: A pregnant mare died two days after arrival from a paddock elsewhere in Brisbane. Eight to 11 days later, illness (depression, anorexia, fever, dyspnoea, ataxia, tachycardia, tachypnoea and nasal discharge) was reported among 17 other horses from the same or an adjoining stable. Fourteen horses died or were put down. Five and six days after the index mare...
Weaver SC, Salas R, Rico-Hesse R, Ludwig GV, Oberste MS, Boshell J, Tesh RB.Venezuelan equine encephalomyelitis (VEE) virus has caused periodic epidemics among human beings and equines in Latin America from the 1920s to the early 1970s. The first major outbreak since 1973 occurred in Venezuela and Colombia during 1995, and involved an estimated 75,000 to 100,000 people. We report an epidemiological and virological investigation of this epidemic. Methods: Virus isolates were made in cell culture from human serum, human throat swabs, and brain tissue from aborted and stillborn human fetuses, as well as from horse brain tissue and pooled mosquito collections. Human sera ...
Desquesnes M, Holzmuller P, Lai DH, Dargantes A, Lun ZR, Jittaplapong S.Trypanosoma evansi, the agent of "surra," is a salivarian trypanosome, originating from Africa. It is thought to derive from Trypanosoma brucei by deletion of the maxicircle kinetoplastic DNA (genetic material required for cyclical development in tsetse flies). It is mostly mechanically transmitted by tabanids and stomoxes, initially to camels, in sub-Saharan area. The disease spread from North Africa towards the Middle East, Turkey, India, up to 53° North in Russia, across all South-East Asia, down to Indonesia and the Philippines, and it was also introduced by the conquistadores into Latin ...
Woldehiwet Z.Anaplasma phagocytophilum is the recently designated name replacing three species of granulocytic bacteria, Ehrlichia phagocytophila, Ehrlichia equi and the agent of human granulocytic ehrlichiosis, after the recent reorganization of the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales. Tick-borne fever (TBF), which is caused by the prototype of A. phagocytophilum, was first described in 1932 in Scotland. A similar disease caused by a related granulocytic agent was first described in horses in the USA in 1969; this was followed by the description of two distinct granulocy...
Letchworth GJ, Rodriguez LL, Del cbarrera J.Vesicular stomatitis is a disease of livestock caused by some members of the Vesiculovirus genus (Family Rhabdoviridae), two of which are called 'vesicular stomatitis virus'. Clinical disease presents as severe vesiculation and/or ulceration of the tongue, oral tissues, feet, and teats, and results in substantial loss of productivity. Except for its appearance in horses, it is clinically indistinguishable from foot-and-mouth disease. Unlike foot-and-mouth disease, it is very infectious for man and can cause a temporarily debilitating disease. Vesicular stomatitis occurs seasonally every year i...
Marasas WF.This article describes the events leading to the discovery of the fumonisins in South Africa in 1988 and highlights the first 10 years (1988-1998) of fumonisin research. The predominant fungus isolated from moldy corn implicated in a field outbreak of equine leukoencephalomalacia (ELEM) in South Africa in 1970 was Fusarium verticillioides (F. moniliforme). This fungus was also prevalent in moldy home-grown corn consumed by people in high-incidence areas of esophageal cancer (EC) in the Transkei region of South Africa. Culture material on corn of F. verticillioides strain MRC 826, which was iso...
O'Sullivan JD, Allworth AM, Paterson DL, Snow TM, Boots R, Gleeson LJ, Gould AR, Hyatt AD, Bradfield J.In September, 1994, an outbreak of severe respiratory disease affected 18 horses, their trainer, and a stablehand in Queensland, Australia. Fourteen horses and one human being died. A novel virus was isolated from those affected and named equine morbillivirus (EMV). We report a case of encephalitis caused by this virus. Results: A 35-year-old man from Queensland had a brief aseptic meningitic illness in August, 1994, shortly after caring for two horses that died from EMV infection and then assisting at their necropsies. He then suffered severe encephalitis 13 months later, characterised by unc...
Murgue B, Murri S, Zientara S, Durand B, Durand JP, Zeller H.On September 6, 2000, two cases of equine encephalitis caused by West Nile (WN) virus were reported in southern France (Hérault Province), near Camargue National Park, where a WN outbreak occurred in 1962. Through November 30, 76 cases were laboratory confirmed among 131 equines with neurologic disorders. The last confirmed case was on November 3, 2000. All but three cases were located in a region nicknamed "la petite Camargue," which has several large marshes, numerous colonies of migratory and resident birds, and large mosquito populations. No human case has been confirmed among clinically ...
Ching PK, de los Reyes VC, Sucaldito MN, Tayag E, Columna-Vingno AB, Malbas FF, Bolo GC, Sejvar JJ, Eagles D, Playford G, Dueger E, Kaku Y....During 2014, henipavirus infection caused severe illness among humans and horses in southern Philippines; fatality rates among humans were high. Horse-to-human and human-to-human transmission occurred. The most likely source of horse infection was fruit bats. Ongoing surveillance is needed for rapid diagnosis, risk factor investigation, control measure implementation, and further virus characterization.
Komar N, Clark GG.West Nile virus (Flavivirus: Flaviviridae; WNV) has spread rapidly throughout the Caribbean Basin since its initial detection there in 2001. This report summarizes our current knowledge of WNV transmission in tropical America. Methods: We reviewed the published literature and consulted with key public health officials to obtain unpublished data. Results: West Nile virus infections first appeared in human residents of the Cayman Islands and the Florida Keys in 2001, and in apparently healthy Jamaican birds sampled early in 2002. Serologic evidence of WNV infection in 2002 was detected in horses...
Lunn DP, Davis-Poynter N, Flaminio MJ, Horohov DW, Osterrieder K, Pusterla N, Townsend HG.Equine herpesvirus-1 is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). In recent years, there has been an apparent increase in the incidence of EHM in North America, with serious consequences for horses and the horse industry. This consensus statement draws together current knowledge in the areas of pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment.
Murray KO, Mertens E, Despres P.Zoonotic West Nile virus (WNV) circulates in natural transmission cycles involving certain mosquitoes and birds, horses, humans, and a range of other vertebrates are incidental hosts. Clinical infections in humans can range in severity from uncomplicated WNV fever to fatal meningoencephalitis. Since its introduction to the Western Hemisphere in 1999, WNV had spread across North America, Central and South America and the Caribbean, although the vast majority of severe human cases have occurred in the United States of America (USA) and Canada. By 2002-2003, the WNV outbreaks have involved thousa...
Sangioni LA, Horta MC, Vianna MC, Gennari SM, Soares RM, Galvu00e3o MA, Schumaker TT, Ferreira F, Vidotto O, Labruna MB.We compared the rickettsial infection status of Amblyomma cajennense ticks, humans, dogs, and horses in both Brazilian spotted fever (BSF)-endemic and -nonendemic areas in the state of Sao Paulo, Brazil. Most of the horses and few dogs from BSF-endemic areas had serologic titers against Rickettsia rickettsii antigens. In contrast, no dogs or horses from BSF-nonendemic areas had serologic titers against R. rickettsii antigens, although they were continually exposed to A. cajennense ticks. All human serum samples and ticks from both areas were negative by serologic assay and polymerase chain rea...
Mellor PS, Hamblin C.African horse sickness virus (AHSV) causes a non-contagious, infectious insect-borne disease of equids and is endemic in many areas of sub-Saharan Africa and possibly Yemen in the Arabian Peninsula. However, periodically the virus makes excursions beyond its endemic areas and has at times extended as far as India and Pakistan in the east and Spain and Portugal in the west. The vectors are certain species of Culicoides biting midge the most important of which is the Afro-Asiatic species C. imicola. This paper describes the effects that AHSV has on its equid hosts, aspects of its epidemiology, a...
Nugent J, Birch-Machin I, Smith KC, Mumford JA, Swann Z, Newton JR, Bowden RJ, Allen GP, Davis-Poynter N.Equid herpesvirus 1 (EHV-1) can cause a wide spectrum of diseases ranging from inapparent respiratory infection to the induction of abortion and, in extreme cases, neurological disease resulting in paralysis and ultimately death. It has been suggested that distinct strains of EHV-1 that differ in pathogenic capacity circulate in the field. In order to investigate this hypothesis, it was necessary to identify genetic markers that allow subgroups of related strains to be identified. We have determined all of the genetic differences between a neuropathogenic strain (Ab4) and a nonneuropathogenic ...
Autorino GL, Battisti A, Deubel V, Ferrari G, Forletta R, Giovannini A, Lelli R, Murri S, Scicluna MT.During the late summer of 1998, veterinary authorities in Tuscany, Italy, received reports of cases of neurologic disease among horses residing in a large wetland area located in the provinces of Florence and Pistoia. West Nile virus was isolated from two of the six horses that died or were euthanized. A retrospective epidemiologic study identified 14 clinical neurologic cases that occurred from August 20 to October 6 (attack rate of 2.8%). A serologic survey conducted over a 700-km2 area in stables with and without apparent clinical cases confirmed a wider spread of the infection, with an ove...
Chandriani S, Skewes-Cox P, Zhong W, Ganem DE, Divers TJ, Van Blaricum AJ, Tennant BC, Kistler AL.Theiler's disease is an acute hepatitis in horses that is associated with the administration of equine blood products; its etiologic agent has remained unknown for nearly a century. Here, we used massively parallel sequencing to explore samples from a recent Theiler's disease outbreak. Metatranscriptomic analysis of the short sequence reads identified a 10.5-kb sequence from a previously undescribed virus of the Flaviviridae family, which we designate "Theiler's disease-associated virus" (TDAV). Phylogenetic analysis clusters TDAV with GB viruses of the recently proposed Pegivirus genus, altho...
Ewers C, Bethe A, Stamm I, Grobbel M, Kopp PA, Guerra B, Stubbe M, Doi Y, Zong Z, Kola A, Schaufler K, Semmler T, Fruth A, Wieler LH, Guenther S.To discern the relevance of ST648 extended-spectrum β-lactamase (ESBL)-producing Escherichia coli as a putative new group of multiresistant and extraintestinal pathogenic strains in animals, its frequency, ESBL types, antimicrobial resistance patterns and virulence gene (VG) profiles should be determined and compared with ST131 strains from the same collection of strains. Methods: ESBL-producing E. coli isolates (n = 1152), consecutively sampled from predominantly dogs, cats and horses between 2008 and 2011, were assigned to a phylogenetic group by PCR. Partial multilocus sequence typing was ...
Wise LN, Kappmeyer LS, Mealey RH, Knowles DP.Equine piroplasmosis is caused by one of 2 erythrocytic parasites Babesia caballi or Theileria equi. Although the genus of the latter remains controversial, the most recent designation, Theileria, is utilized in this review. Shared pathogenesis includes tick-borne transmission and erythrolysis leading to anemia as the primary clinical outcome. Although both parasites are able to persist indefinitely in their equid hosts, thus far, only B. caballi transmits across tick generations. Pathogenesis further diverges after transmission to equids in that B. caballi immediately infects erythrocytes, wh...
Rivas F, Diaz LA, Cardenas VM, Daza E, Bruzon L, Alcala A, De la Hoz O, Caceres FM, Aristizabal G, Martinez JW, Revelo D, De la Hoz F, Boshell J....In 1995, the first Venezuelan equine encephalitis (VEE) outbreak in Colombia in 22 years caused an estimated 75,000 human cases, 3000 with neurologic complications and 300 fatal, in La Guajira State. Of the state's estimated 50,000 equines, 8% may have died. An epizootic IC virus, probably introduced from Venezuela, was rapidly amplified among unvaccinated equines. Record high rainfall, producing high densities of vector Aedes taeniorhynchus, led to extensive epidemic transmission (30% attack rate) in the four affected municipalities. Native Wayuu Indians, constituting 24% of the state's popul...
Murcia PR, Baillie GJ, Daly J, Elton D, Jervis C, Mumford JA, Newton R, Parrish CR, Hoelzer K, Dougan G, Parkhill J, Lennard N, Ormond D, Moule S....Determining the evolutionary basis of cross-species transmission and immune evasion is key to understanding the mechanisms that control the emergence of either new viruses or novel antigenic variants with pandemic potential. The hemagglutinin glycoprotein of influenza A viruses is a critical host range determinant and a major target of neutralizing antibodies. Equine influenza virus (EIV) is a significant pathogen of the horse that causes periodical outbreaks of disease even in populations with high vaccination coverage. EIV has also jumped the species barrier and emerged as a novel respirator...
Frost MJ, Zhang J, Edmonds JH, Prow NA, Gu X, Davis R, Hornitzky C, Arzey KE, Finlaison D, Hick P, Read A, Hobson-Peters J, May FJ, Doggett SL....To determine the cause of an unprecedented outbreak of encephalitis among horses in New South Wales, Australia, in 2011, we performed genomic sequencing of viruses isolated from affected horses and mosquitoes. Results showed that most of the cases were caused by a variant West Nile virus (WNV) strain, WNV(NSW2011), that is most closely related to WNV Kunjin (WNV(KUN)), the indigenous WNV strain in Australia. Studies in mouse models for WNV pathogenesis showed that WNV(NSW2011) is substantially more neuroinvasive than the prototype WNV(KUN) strain. In WNV(NSW2011), this apparent increase in vir...
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