Infectious diseases in horses encompass a range of illnesses caused by bacteria, viruses, fungi, or parasites. These diseases can affect various systems within the equine body, leading to symptoms that range from mild discomfort to severe systemic illness. Common infectious diseases in horses include equine influenza, strangles, equine herpesvirus, and West Nile virus. These diseases can be transmitted through direct contact with infected animals, contaminated surfaces, or vectors such as insects. Understanding the mechanisms of transmission, pathogenesis, and immune response is essential for effective prevention and control. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, diagnosis, treatment, and management of infectious diseases in horses.
Yao Q, Ma J, Wang X, Guo M, Li Y, Wang X.Tetherin (BST-2) is an important host restriction factor that can inhibit the release of a diverse array of enveloped viruses from infected cells. Conversely, to facilitate their release and spread, many viruses have evolved various strategies to overcome the antiviral effect of tetherin in a species-specific manner. During the development of an attenuated equine infectious anemia virus (EIAV) vaccine in our laboratory, we found that serial passage of a field-isolated virulent EIAV strains in horse and donkey as well as the cultivated donkey cells, produces several typical EIAV strains, includ...
of surveillance testing, April to June 2016Continuing reports of abortion due to equine herpesvirus type 1 infectionInternational disease occurrence in the second quarter of 2016These are among matters discussed in the most recent quarterly equine disease surveillance report, prepared by Defra, the Animal Health Trust and the British Equine Veterinary Association.
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...
Deng L, Li W, Zhong Z, Gong C, Liu X, Huang X, Xiao L, Zhao R, Wang W, Feng F, Zhang Y, Hu Y, Fu H, He M, Zhang Y, Wu K, Peng G.Enterocytozoon bieneusi is one of the most prevalent causative species of diarrhea and enteric diseases in various hosts. E. bieneusi has been identified in humans, mammals, birds, rodents and reptiles in China, but few studies have reported E. bieneusi in horses. Therefore, the present study was conducted to assess the prevalence, molecular characteristics and zoonotic potential of E. bieneusi among horses in southwestern China. Three hundred and thirty-three fecal specimens were collected from horses on five farms in the Sichuan and Yunnan provinces of southwestern China. The prevalence of E...
Efforts to detect West Nile virus (WNV) in the Vojvodina province, northern Serbia, commenced with human and mosquito surveillance in 2005, followed by horse (2009) and wild bird (2012) surveillance. The knowledge obtained regarding WNV circulation, combined with the need for timely detection of virus activity and risk assessment resulted in the implementation of a national surveillance programme integrating mosquito, horse and bird surveillance in 2014. From 2013, the system showed highly satisfactory results in terms of area specificity (the capacity to indicate the spatial distribution of t...
Lia RP, Mutafchiev Y, Veneziano V, Giannelli A, Abramo F, Santoro M, Latrofa MS, Cantacessi C, Martin C, Otranto D, Bertuglia A, Riccio B.Equids can be infected by a range of skin-dwelling filarial nematodes, including four species of the genus Onchocerca. Current literature on equine onchocercosis is fragmentary and often limited to isolated case reports. The present study aimed to describe a clinical case of equine onchocercosis caused by Onchocerca boehmi (Supperer, 1953) (syn. Elaeophora boehmi) in an 8-year-old gelding Belgian show jumper from northern Italy. The horse was presented with a firm and painless mass on the proximal third of the right metacarpal region. Ultrasound examination showed a peritendinous enlargement a...
Kupke A, Wenisch S, Failing K, Herden C.The olfactory epithelium (OE) is the only body site where neurons contact directly the environment and are therefore exposed to a broad variation of substances and insults. It can serve as portal of entry for neurotropic viruses which spread via the olfactory pathway to the central nervous system. For horses, it has been proposed and concluded mainly from rodent studies that different viruses, e.g., Borna disease virus, equine herpesvirus 1 (EHV-1), hendra virus, influenza virus, rabies virus, vesicular stomatitis virus can use this route. However, little is yet known about cytoarchitecture, p...
Stringer AP, Christley RM, Bell CE, Gebreab F, Tefera G, Reed K, Trawford A, Pinchbeck GL.Working horses, donkeys and mules suffer from numerous diseases and clinical problems. However, there is little information on what owners perceive as important health concerns in their working animals. Objective: To identify and prioritise with owners the diseases and other health concerns in working equids in central Ethiopia using participatory methodologies. Methods: Participatory situation analysis (PSA). Methods: The study was conducted with carthorse- and donkey-owners in 16 sites in central Ethiopia. Multiple participatory methodologies were utilised, including ranking, matrices and fo...
Proft A, Spiesschaert B, Izume S, Taferner S, Lehmann MJ, Azab W.The serine-threonine protein kinase encoded by gene (pUS3) of alphaherpesviruses was shown to modulate actin reorganization, cell-to-cell spread, and virus egress in a number of virus species. However, the role of the US3 orthologues of equine herpesvirus type 1 and 4 (EHV-1 and EHV-4) has not yet been studied. Here, we show that is not essential for virus replication in vitro. However, growth rates and plaque diameters of a -deleted EHV-1 and a mutant in which the catalytic active site was destroyed were significantly reduced when compared with parental and revertant viruses or a virus in w...
Takahashi T, Unuma S, Kawagishi S, Kurebayashi Y, Takano M, Yoshino H, Minami A, Yamanaka T, Otsubo T, Ikeda K, Suzuki T.Most equine influenza A viruses (IAVs) show strong binding to glycoconjugates containing N-glycolylneuraminic acid (Neu5Gc) as well as N-acetylneuraminic acid (Neu5Ac). Therefore, the progeny of equine IAV is thought to be released from the infected cell surface through removal of sialic acids by the viral sialidase. In the present study, equine IAV sialidases showed significantly lower substrate affinity than that of human IAV sialidases to artificial and natural Neu5Gc-conjugated substrates. The substrate specificity of equine IAV sialidases is in disagreement with their binding specificity ...
Mayo C, Venter E, Steyn J, Coetzee P, van Vuuren M, Crafford J, Schütte C, Venter G.The seasonal abundance of Culicoides midges, the vector of Bluetongue and African horse sickness viruses (BTV/AHSV) and the presence of viruses in midges were determined in 3 geographic areas in South Africa. In the Onderstepoort area, more than 500,000 Culicoides midges belonging to 27 species were collected. Eighteen midge species were collected throughout Winter and the presence of AHSV and BTV RNA in midges was detected using real time reverse transcription quantitative polymerase chain reaction. The nucleic acid of AHSV was found in 12 pools out of total pools of 35 Culicoides. Twenty‑f...
Grewar JD.Bluetongue (BT) and African horse sickness (AHS) are considered the most important orbiviral diseases in Southern Africans countries. The general endemic status makes these diseases challenging to be quanti ed in terms of their economic impact. Using country reported data from BT and AHS outbreaks and cases, as well as international trade data, the economic impact of BT and AHS is evaluated on local, regional, and global scales. Local scale impact in the Southern African region is underestimated as shown by the underreporting of BT and AHS. Exceptions occur during epidemic cycles of the diseas...
Ojo KK, Dangoudoubiyam S, Verma SK, Scheele S, DeRocher AE, Yeargan M, Choi R, Smith TR, Rivas KL, Hulverson MA, Barrett LK, Fan E, Maly DJ....Sarcocystis neurona is the most frequent cause of equine protozoal myeloencephalitis, a debilitating neurological disease of horses that can be difficult to treat. We identified SnCDPK1, the S. neurona homologue of calcium-dependent protein kinase 1 (CDPK1), a validated drug target in Toxoplasma gondii. SnCDPK1 shares the glycine "gatekeeper" residue of the well-characterized T. gondii enzyme, which allows the latter to be targeted by bumped kinase inhibitors. This study presents detailed molecular and phenotypic evidence that SnCDPK1 can be targeted for rational drug development. Recombinant ...
Corbeil LE, Morrissey JF, Léguillette R.This report describes 5 horses in the southern Alberta region with typical and atypical external abscessation due to Corynebacterium pseudotuberculosis (pigeon fever). "Pigeon fever" has recently been diagnosed in new geographic regions in North America and should be kept as a differential diagnosis by practitioners when an external or internal abscess is identified in a horse. L’infection parCorynebacterium pseudotuberculosis(fièvre du pigeon) chez les chevaux est-elle une maladie émergente dans l’Ouest canadien? Ce rapport décrit cinq chevaux dans la région sud de l’Alberta atteint...
Welsh CE, Parkin TDH, Marshall JF.As antimicrobial resistant bacterial strains continue to emerge and spread in human and animal populations, understanding prescription practices is key in benchmarking current performance and setting goals. Antimicrobial prescription (AP) in companion veterinary species is widespread, but is neither monitored nor restricted in the USA and Canada. The veterinary use of certain antimicrobial classes is discouraged in some countries, in the hope of preserving efficacy for serious human infections. Objective: The aim of this study was to ascertain the rate of prescription of a number of 'reserved'...
Basile RC, Yoshinari NH, Mantovani E, Bonoldi VN, Macoris DD, Queiroz-Neto A.Borreliosis caused by Borrelia burgdorferi sensu lato is a cosmopolitan zoonosis studied worldwide; it is called Lyme disease in many countries of the Northern Hemisphere and Lyme-like or Baggio-Yoshinari Syndrome in Brazil. However, despite the increasing number of suspect cases, this disease is still neglected in Brazil by the medical and veterinary communities. Brazilian Lyme-like borreliosis likely involves capybaras as reservoirs and Amblyomma and Rhipicephalus ticks as vectors. Thus, domestic animals can serve as key carriers in pathogen dissemination. This zoonosis has been little studi...
Sting R, Seeh C, Mauder N, Maurer M, Loncaric I, Stessl B, Kopp P, Banzhaf K, Martin B, Melzer F, Raßbach A, Spergser J.A total of 124 Taylorella (T.) equigenitalis and five T. asinigenitalis field isolates collected between 2002 and 2014 were available for genotyping using REP- (repetitive extragenic palindromic) PCR and PFGE (pulsed-field gel electrophoresis). The study comprised 79 T. equigenitalis field isolates originating from ten defined breeds of German horses and revealed a spectrum of five REP (rep-E1-E4, rep-E3a) and 15 PFGE (TE-A1-A9, TE-B1-B3, TE-C, TE-E1, and TE-E2) genotypes. T. equigenitalis field isolates (n=40) obtained from Austrian Lipizzaner horses were differentiated into three REP (rep-E1...
Anagha G, Gulati BR, Riyesh T, Virmani N.Equine herpesvirus 1 (EHV1) is a common pathogen of horses that causes upper respiratory tract disease, abortion, neonatal death and neurological disease. The neurological form of disease is called equine herpesvirus myeloencephalopathy (EHM). During the past decade, the incidence of EHM has been on the rise in Europe, North America, Australia and Asia. Some EHV1 isolates causing EHM exhibit a single-nucleotide polymorphism (SNP) in the DNA polymerase gene (ORF30) at position 2254 (A to G). Further, based on polymorphism in the ORF68, EHV1 isolates have been classified into different groups. T...
Chapman GE, Archer D, Torr S, Solomon T, Baylis M.There is growing concern about the increasing risk of disease outbreaks caused by arthropod-borne viruses (arboviruses) in both human beings and animals. There are several mosquito-borne viral diseases that cause varying levels of morbidity and mortality in horses and that can have substantial welfare and economic ramifications. While none has been recorded in the UK, vector species for some of these viruses are present, suggesting that UK equines may be at risk. The authors undertook, therefore, the first study of mosquito species on equine premises in the UK. Mosquito magnet traps and red-bo...
Meseko CA, Ehizibolo DO, Nwokike EC, Wungak YS.Equine influenza virus (EIV) is a major cause of acute respiratory diseases in horses in most parts of the world that results in severe economic losses. Information on the epidemiology of EIV in tropical Africa is scanty. An enzyme-linked immunosorbent assay (ELISA) was used to detect the presence of influenza A virus nucleoprotein (NP) in 284 horse sera in Kaduna State, Northern Nigeria. The ELISA-positive sera were further examined for hemagglutination inhibition (HI) antibodies to two strains each of H3N8 and H7N3 subtypes of influenza A virus. The results showed that antibodies against inf...
Rizzo C, Napoli C, Venturi G, Pupella S, Lombardini L, Calistri P, Monaco F, Cagarelli R, Angelini P, Bellini R, Tamba M, Piatti A, Russo F, Palù G....In Italy a national Plan for the surveillance of imported and autochthonous human vector-borne diseases (chikungunya, dengue, Zika virus disease and West Nile virus (WNV) disease) that integrates human and veterinary (animals and vectors) surveillance, is issued and revised annually according with the observed epidemiological changes. Here we describe results of the WNV integrated veterinary and human surveillance systems in Italy from 2008 to 2015. A real time data exchange protocol is in place between the surveillance systems to rapidly identify occurrence of human and animal cases and to de...
Curto E, Messenger KM, Salmon JH, Gilger BC.To determine whether horses with clinically diagnosed Equine Recurrent Uveitis (ERU) and those with Leptospirosis infection have a specific cytokine profile in their aqueous humor (AH) and serum that differs from horses with uveitis secondary to other ocular inflammatory processes and from horses with normal eyes. Methods: Twenty-five client-owned horses with uveitis that were presented to the North Carolina State University Ophthalmology Service, and four University-owned horses without history or clinical signs of ocular disease. Methods: Samples of AH and serum were obtained from horses wit...
Simbizi V, Saulez MN, Potts A, Lötter C, Gummow B.Most leptospiral infections in horses are asymptomatic; however, acute disease manifestations as well as reproductive failure and recurrent uveitis have been reported. In South Africa, the epidemiology of the disease in horses is not well documented. A serosurvey to determine what serovars were present in horses from Gauteng, KwaZulu-Natal and Western Cape Provinces and to get an estimate of the seroprevalence of leptospirosis was carried out from January 2013 until April 2014 with the assistance of four large equine hospitals located in these provinces. Furthermore, associations between poten...
Faverjon C, Leblond A, Lecollinet S, Bødker R, de Koeijer AA, Fischer EAJ.African horse sickness (AHS) and equine encephalosis (EE) are Culicoides-borne viral diseases that could have the potential to spread across Europe if introduced, thus being potential threats for the European equine industry. Both share similar epidemiology, transmission patterns and geographical distribution. Using stochastic spatiotemporal models of virus entry, we assessed and compared the probabilities of both viruses entering France via two pathways: importation of live-infected animals or importation of infected vectors. Analyses were performed for three consecutive years (2010-2012). Se...
Ayala-Valdovinos MA, Lemus-Flores C, Galindo-García J, Bañuelos-Pineda J, Rodríguez-Carpena JG, Sánchez-Chiprés D, Duifhuis-Rivera T.Theileria equi infection prevalence was calculated from 1000 blood samples obtained from apparently healthy horses in western Mexico. Samples were sent to the Animal Biotechnology Laboratory of the University of Guadalajara (Mexico) for T. equi diagnosis. Nested polymerase chain reaction (nPCR) was used as a diagnostic method to detect pathogen DNA. Using primers for the merozoite antigen-1 (EMA-1) gene, 19.70±2.47% of the horses (95% CI, 17.23-22.17%) tested positive for T. equi. There was no significant association between gender and T. equi infection. However, prevalence was higher among s...
Hu Z, Chang H, Chu X, Li S, Wang M, Wang X.The equine infectious anemia virus (EIAV) capsid protein (p26) is one of the major immunogenic proteins during EIAV infection and is widely used for the detection of EIAV antibodies in horses. However, few reports have described the use of EIAV-specific monoclonal antibodies (MAbs) in etiological and immunological detection. Previously, we developed an antigen capture enzyme-linked immunosorbent assay (AC-ELISA) for the quantification of the EIAV p26 protein level. However, the epitopes recognized by the MAbs were not identified, and the utilization of the MAbs needs to be evaluated. In this ...
Gather T, Walter S, Pfaender S, Todt D, Feige K, Steinmann E, Cavalleri JM.The recently discovered nonprimate hepacivirus (NPHV) naturally infects horses and is the closest known homolog of hepatitis C virus to date. Within a follow-up study acute field infections were monitored in four young Thoroughbred horses until the ages of 12-13 months. Serum samples were analyzed for the presence of NPHV RNA and anti-NPHV NS3 antibodies and liver specific parameters were evaluated. The four young horses were not able to clear infection, but remained chronically infected for the entire monitored time period despite the presence of NPHV specific antibodies.
Walter J, Seeh C, Fey K, Bleul U, Osterrieder N.Equine herpesvirus myeloencephalopathy (EHM) is a severe manifestation of equine herpesvirus 1 (EHV-1) infection. Prevention and treatment of EHM during EHV-1 outbreaks is critical, but no reliable and tested specific medication is available. Due to the thromboischemic nature of EHM and due to the fact that EHV-1 entry in cells is blocked by heparin, it was hypothesized that this compound may be useful in reduction of EHM incidence and severity. Therefore, during an acute EHV-1 outbreak with the neuropathogenic G/D Pol variant, metaphylactic treatment with heparin to prevent EHM was initiated....
Velineni S, Timoney JF.Immunogenic proteins of Leptospira interrogans serovar Pomona type kennewicki (Lk) including Sph1, LigA, Hsp15 and LipL45 (Qlp42) are up-regulated in infected horses but are undetectable or expressed in trace amounts on cultured organisms. In contrast, LipL32 is abundant on cultured Lk and elicits infection antibody responses. The aim of this study was to develop an ELISA based on LipL32 or Lk sonicate and host-induced proteins to differentiate vaccine from infection serum antibody. IgG specific for recombinant Sph1, LigA, Lk90 (LigA; 379-1225 a.a), Hsp15, LipL45 and LipL32 of Lk were assayed ...
Imagawa H, Ishida S, Uesugi S, Masanobu K, Fukunaga Y, Nakagomi O.Serotype G3 equine rotaviruses isolated in Japan made up a common genogroup and were classified into two different genotypes. The genomes of serotype G3 equine rotaviruses with an identical electropherotype (isolated from 1982 to 1989) were very closely related to each other regardless of the year in which they were isolated. Serotype G3 equine rotavirus BI originating from England belonged to the same genogroup of serotype G3 equine rotaviruses isolated in Japan, although BI was classified as having a different genotype. The genomes of both serotype G10 equine rotavirus R-22 and serotype G10 ...
Paweska JT, Venter GJ.Field-collected Culicoides species (Diptera: Ceratopogonidae) were fed on horse blood-virus mixtures containing one of the six serotypes of equine encephalosis virus (EEV1 to EEV6). The virus mean titres in the bloodmeals varied between 6.1 and 7.0 log10TCID50/mL. Of 19 Culicoides species assayed after 10 days extrinsic incubation at 23.5 degrees C, five yielded the challenge virus, namely Culicoides (Avaritia) imicola Kieffer (EEV1-6), C. (A.) bolitinos Meiswinkel (EEV1, 2, 4, 6), C. (Meijerehelea) leucostictus Kiefer (EEV1, 2), C. (Culicoides) magnus Colaço (EEV1) and C. (Hoffmania) zuluens...
McGlennon A, Waller A, Verheyen K, Slater J, Grewar J, Aanensen D, Newton R.Previously national surveillance data for monitoring strangles (Streptococcus equi infection) in UK horses was limited. Improved awareness and knowledge of positive diagnoses would permit the optimisation of biosecurity protocols, decreasing the prevalence of strangles. Methods: Seven UK laboratories reported positive strangles diagnoses between 1 January 2015 and 31 December 2019 based on identifying Streptococcus equi via agent detection assays from field-based practitioner-submitted samples. Associated clinical history and animal signalment were collected where provided, and descriptive ana...
Yoshikawa H, Yasu T, Ueki H, Oyamada T, Oishi H, Anzai T, Oikawa M, Yoshikawa T.To evaluate the possibility that Streptococcus equi subsp. zooepidemicus (S.z) the causative bacterial agent of equine shipping fever pneumonia (ESFP), as well as to investigate its pathogenesis, 10 horses (seven Thoroughbreds and three Anglo-Arab species, ranging from 2-4 years in age) were experimentally inoculated, via an endoscope, into bronchus of the lung lobe with a dose of 30 ml of 1-7 x 10(8) CFU/ml of S.z. After inoculation, autopsy and pathological examinations were sequentially conducted 30 min, 1, 2, 3, 4, 17, 20 hr and 2 weeks later. Pneumonia induced by the intrapulmonary inocul...
Cantú-Martínez MA, Segura-Correa JC, Silva-Páez ML, Avalos-Ramírez R, Wagner GG.The objective of this study was to obtain an estimate for seroprevalences of Theileria equi (Babesia equi) and Babesia caballi in horses from northeastern Mexico. Sera were collected in spring of 2007 in 248 clinically healthy horses used for different purposes. Antibodies were detected by the indirect immunofluorecent technique. The overall seroprevalence was 61.7% and those for T. equi and B. caballi were 45.2% and 27.4%, respectively. Horse purpose, sex, and age group were not associated with infection with Theileria equi or Babesia caballi.
Higgins R, Cayouette P, Hoquet F, De LaSalle F.During a period of 30 months, from January 1977 to June 1979, Leptospira agglutinins were detected in 355 (6%) of 5841 bovine sera, 52 (10.1%) of 511 porcine sera, one (5%) of 20 equine sera and one (12.5%) of eight canine sera. Bovine, porcine and equine sera reacted predominantly with L. pomona. Reactors to L. hardjo/sejroe, L. icterohaemorrhagiae and L. grippotyphosa were also detected in cattle. One porcine serum reacted with L. grippotyphosa and one canine serum with L. icterohaemorrhagiae. Al the sera originated from suspected cases of leptospirosis.
Bucknell D, Hoste H, Gasser RB, Beveridge I.The community structure exhibited by strongyloid nematodes from the large intestines of horses was examined using data from autopsies of 150 horses. Thirty-one species of nematodes were encountered, but they were not clearly divisible into core and satellite species. Multiple congeneric, consubfamilial and confamilial species were a prominent feature of the community and were more common than singleton infections. Multivariate analyses provided evidence of a stable community of helminths dominated by positive interactions but with few negative interactions, suggesting the absence of competitio...
TSUJIMURA K, SHIOSE T, YAMANAKA T, NEMOTO M, KONDO T, MATSUMURA T.An equine herpesvirus type 1 (EHV-1) mutant, DeltagE, defective in glycoprotein E (gE) was evaluated as a modified live virus (MLV) vaccine. Colostrum-deprived Thoroughbred foals inoculated intranasally (i.n.) or intramuscularly (i.m.) with DeltagE did not exhibit any clinical signs of respiratory disease except for a mild nasal discharge in 1 i.n. inoculated foal on Days 1 and 3 post-infection. In contrast, the intranasal inoculation of foals with the revertant of DeltagE resulted in biphasic pyrexia, mucopurulent nasal discharge and swelling of submandibular lymph nodes. These results indica...
Hagiwara K, Kamitani W, Takamura S, Taniyama H, Nakaya T, Tanaka H, Kirisawa R, Iwai H, Ikuta K.A pregnant mare showing pyrexia, reduced appetite, ataxia and paresis was euthanized and examined for the presence of Borna disease virus (BDV). Her brain, showing multiple neuronal degeneration and necrosis with hemorrhage, and the histologically normal brain of the fetus were both positive for BDV RNA. The BDV nucleotide sequences were identical in the mare and fetus in the second open reading frame (ORF). This is the first report of the possible vertical transmission of BDV in a horse.
Smith M, Tzipori S.Rotavirus RNA prepared from calf, pig, mouse, deer, foal and dog-adapted human isolates was compared using polyacrylamide gel electrophoresis. Reproducible differences in the RNA migration patterns were found between all isolates. There were 11 clearly resolved segments in the pig, mouse and foal samples. The calf rotavirus RNA and deer rotavirus RNA separated into 9 bands and 10 bands, respectively. The dog-adapted human virus migrated in 12 bands, and this probably results from the complex passage history of the original human rotavirus isolate.
Paterson DL, Murray PK, McCormack JG.Twenty-three horses and three humans in Queensland, Australia, were infected with a novel member of the Paramyxoviridae family of viruses in two geographically distinct outbreaks. Two of the humans died-one died of rapid-onset respiratory illness, and the other died of encephalitis. The third infected human developed an influenza-like illness and made a complete recovery. All infected humans had close contact with sick horses. Since the two outbreaks occurred at sites 1,000 km apart and no known contact between the two groups of humans and horses occurred, extensive testing of animals and bird...
Nielsen MK, Olsen SN, Lyons ET, Monrad J, Thamsborg SM.Strongyle parasites are ubiquitous in grazing horses, and the large strongyle Strongylus vulgaris is considered the most pathogenic helminth parasite of horses. Recent investigations have suggested an association between occurrence of this parasite and usage of selective therapy based on regular fecal egg counts. The established diagnostic method for S. vulgaris involves larval culture and subsequent morphological identification of third stage larvae under the microscope. Recently, a real-time PCR assay was developed and validated for the detection and semi-quantification of S. vulgaris eggs i...
Malalana F, Blundell RJ, Pinchbeck GL, Mcgowan CM.Equine recurrent uveitis (ERU) is a common cause of ocular pain and blindness in horses. Leptospira spp. have been commonly implicated in the pathophysiology of ERU in mainland Europe and the USA. No recent studies have been carried out in the UK, but Leptospira is reported not to be a major factor in the aetiology of ERU in the UK. Objective: To establish the prevalence of Leptospira-associated ERU in the UK and to identify the serovars involved in these cases; to compare serum vs. aqueous humour antibody levels in cases and controls in order to confirm the diagnosis of Leptospira-associated ...
Robb LL, Hartman DA, Rice L, deMaria J, Bergren NA, Borland EM, Kading RC.Western equine encephalitis (WEE) was once prevalent and routinely isolated from mosquitoes in Colorado; however, isolations of Western equine encephalitis virus (WEEV) have not been reported from mosquito pools since the early 1990s. The objective of the present study was to test pools of Culex tarsalis (Coquillett) mosquitoes sampled from Weld County, CO, in 2016 for evidence of WEEV infection. Over 7,000 mosquitoes were tested, but none were positive for WEEV RNA. These data indicate that WEEV either was not circulating enzootically in Northern Colorado, was very rare, and would require muc...
Khan I, Wieler LH, Melzer F, Gwida M, Santana VL, de Souza MM, Saqib M, Elschner MC, Neubauer H.The sensitivity and specificity of three commercially available complement fixation test (CFT) antigens from c.c.pro (c.c.pro), Central Veterinary Institute of Wageningen UR (CIDC) and the United States Department of Agriculture (USDA) were comparatively evaluated by testing 410 sera collected from glanders-endemic and non-endemic areas (200 true-negative randomly collected sera and 210 sera collected from experimentally immunised animals (12 rabbits, 19 horses), clinically positive (135) and culture-positive (44) horses, donkeys and mules). Immunoblotting (IB) was used as the gold standard te...
Carvelli A, Nielsen SS, Paillot R, Broglia A, Kohnle L.Equine herpesvirus-1 (EHV-1) can affect the entire equine sector in EU, and the large outbreak reported in 2021 in Spain drew attention to the needs of the European Commission for scientific advice for the assessment of EHV-1 infection within the framework of Animal Health Law. EHV-1 is considered endemic in the EU; its main risk is linked to the characteristic of producing latent life-long infections. These can reactivate producing clinical disease, which can include respiratory, abortive and possibly fatal neurological forms. From the epidemiological and genomic viewpoint, there are no speci...
Khurelbaatar N, Krueger WS, Heil GL, Darmaa B, Ulziimaa D, Tserennorov D, Baterdene A, Anderson BD, Gray GC.In recent years, Mongolia has experienced recurrent epizootics of equine influenza virus (EIV) among its 2·1 million horses and multiple incursions of highly pathogenic avian influenza (HPAI) virus via migrating birds. No human EIV or HPAI infections have been reported. In 2009, 439 adults in Mongolia were enrolled in a population-based study of zoonotic influenza transmission. Enrollment sera were examined for serological evidence of infection with nine avian, three human, and one equine influenza virus strains. Seroreactivity was sparse among participants suggesting little human risk of zoo...
Issel CJ, Cook RF, Mealey RH, Horohov DW.In the absence of an effective vaccine, the success of the test and removal approach for the control of equine infectious anemia (EIA) cannot be overstated, at least in those areas where testing has been traditionally routine. This article addresses 4 main aspects: what has been learned about EIA virus, host control of its replication, and inapparent carriers; international status regarding the control of EIA; diagnostic and laboratory investigation; and reducing the spread of blood-borne infections by veterinarians. An attempt is made to put these issues into practical contemporary perspectiv...
Blackhall WJ, Kuzmina T, von Samson-Himmelstjerna G.Resistance to benzimidazoles (BZ) in the gastrointestinal nematodes of livestock is characterised by the presence of specific polymorphisms in the β-tubulin isotype 1 protein, a component of microtubules. The most prevalent polymorphism associated with resistance in nematodes infecting cattle, sheep, and goats is found at codon 200, with minor occurrences of polymorphisms at codons 167 and 198. In the cyathostomins that infect horses, however, a polymorphism at codon 167 appears to be more common than the codon 200 polymorphism. In the present study, a focussed analysis of PCR-amplified β-tu...
Chanter N, Talbot NC, Newton JR, Hewson D, Verheyen K.The M-protein genes of Streptococcus equi isolated from 17 outwardly healthy horses after 4 strangles outbreaks had ended, including a quarantined animal, were compared with those of S. equi isolates from 167 active cases of strangles across 4 countries. The healthy horses included 16 persistent S. equi carriers, at least one from each of the four outbreaks. These carriers, despite being outwardly healthy, had empyema of the guttural pouch(es), an enlargement of the equine Eustachian tube. A persistent carrier from two of these outbreaks, the quarantined animal and a healthy animal with normal...
Na W, Yeom M, Yuk H, Moon H, Kang B, Song D.This study provides information regarding vaccine research and the epidemiology of influenza virus in neglected hosts (horses and dogs). Equine influenza virus (EIV) causes a highly contagious disease in horses and other equids, and outbreaks have occurred worldwide. EIV has resulted in costly damage to the horse industry and has the ability of cross the host species barrier from horses to dogs. Canine influenza is a virus of equine or avian origin and infects companion animals that live in close contact with humans; this results in possible exposure to the seasonal epizootic influenza virus. ...
Wohlfender FD, Barrelet FE, Doherr MG, Straub R, Meier HP.Neonatal diseases have been grouped and analysed but up-to-date statistically significant information about the incidence and prevalence of diseases in foals is limited. Since the 1950s it has been a common management practice to administer a 3 day course of antimicrobial drugs to neonatal foals. This was shown to significantly reduce the incidence of infections (Platt 1977). Since then management practices have improved and it is widely believed that prophylactic antimicrobial drugs are no longer necessary in foal rearing. Objective: To determine the 30 day incidences or prevalences (dependin...
Spence KL, O'Sullivan TL, Poljak Z, Greer AL.Identifying the contact structure within a population of horses attending a competition is an important element towards understanding the potential for the spread of equine pathogens as the horses subsequently travel from location to location. However, there is limited information in Ontario, Canada to quantify contact patterns of horses. The objective of this study was to describe the network of potential contacts associated with an equestrian show to determine how this network structure may influence potential disease transmission. Results: This was a descriptive study of horses attending an...
Coultous RM, McDonald M, Raftery AG, Shiels BR, Sutton DGM, Weir W.Theileria equi, one of the primary pathogens causing equine piroplasmosis, has previously been sub-classified into a number of clades on the basis of 18S SSU rRNA gene sequence diversity. This partitioning of the parasite population has potential implications for host immunity, treatment and vaccine development. To detect and identify different clade genotypes among and within individual equine blood samples, a novel PCR-based technique was designed and optimized. Theileria equi has only recently been described in The Gambia, and the developed genotyping technique was used to analyse blood sam...
Dutta SK, Vemulapalli R, Biswas B.Ehrlichia risticii is the causative agent of Potomac horse fever (PHF), which continues to be an important disease of horses. Commercial inactivated whole-cell vaccines are regularly used for immunization of horses against the disease. However, PHF is occurring in large numbers of horses in spite of vaccination. In a limited study, 43 confirmed cases of PHF occurred between the 1994 and 1996 seasons; of these, 38 (89%) were in horses that had been vaccinated for the respective season, thereby clearly indicating vaccine failure. A field study of horses vaccinated with two PHF vaccines indicated...
Bell KS, Philp JC, Christofi N, Aw DW.Two regions in the gene coding for 16S rRNA in Rhodococcus equi were selected as species-specific primer sequences for the polymerase chain reaction (PCR). PCR using these primers was tested against 10 strains of R. equi (including the type strain) and gave positive results for all but was negative for all other tested species of Rhodococcus; representatives of the most closely related genera and a number of other bacterial species. This method could therefore be used to identify this species which can infect the lungs or other organs of horses, pigs, humans and other animals.
Murray DR, Ladds PW, Campbell RS.Lesions encountered in a clinicopathological study of cutaneous lesions resembling 'swamp cancer' from horses in North Queensland included 37 cases of subcutaneous phycomycosis, 5 of which were also infected with Habronema sp larvae. In addition 9 cases of primary cutaneous habronemiasis, 58 sarcoids, 12 fibromas, 8 fibrosarcomas, 10 squamous cell carcinomas, 4 haemangiomas, 3 melanomas, 1 papilloma, 1 palpebral adenocarcinoma and 7 cases of simple granulation were diagnosed. Subcutaneous phycomycosis resulted in the most extensive lesions. These were rapidly growing and provided the poorest p...
Mumford EL, Traub-Dargatz JL, Salman MD, Collins JK, Getzy DM, Carman J.To develop a system to monitor and detect acute infections of the upper respiratory tract (i.e., nares, nasopharynx, and pharynx) in horses and to assess the association among specific viral infections, risk factors, and clinical signs of disease. Methods: Prospective study. Methods: 151 horses with clinical signs of acute infectious upper respiratory tract disease (IURD) from 56 premises in Colorado. Methods: Health management data, blood samples, and nasal or nasopharyngeal swab samples were obtained for 151 horses with clinical signs of acute IURD. Of these horses, 112 had an additional blo...
Hardy JL, Apperson G, Asman SM, Reeves WC.After prolonged selection, two hybrid strains of Culex tarsalis were evolved that were highly resistant to infection following ingestion of western equine encephalomyelitis virus. These strains were greater than 25,000-fold more resistant than the most susceptible parental strain when fed on viremic chicks. Resistance was associated with a mesenteronal barrier since both refractory and parental strains were equally susceptible to infection by intrathoracic inoculation. Susceptibility was dominant, possibly incompletely dominant, over resistance. Inheritance was probably polyfactorial but this ...
