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Topic:Infectious Disease
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.
Localised mitogenic activity in horses following infection with Streptococcus equi. Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, a highly contagious upper respiratory disease of equids. Streptococcus equi produces superantigens (sAgs), which are thought to contribute to strangles pathogenicity through non-specific T-cell activation and pro-inflammatory response. Streptococcus equi infection induces abscesses in the lymph nodes of the head and neck. In some individuals, some abscess material remains into the guttural pouch and inspissates over time to form chondroids which can harbour live S. equi. The aim of this study was to determine...
Malignant seminoma in two unilaterally cryptorchid stallions. Two unilateral cryptorchid stallions were referred to the clinic because of chronic debilitating condition with emaciation. Rectal examination, and ultrasound and gross examination revealed in both animals an abdominal mass, caudally of the kidney, and multiple nodules spread over the abdomen. Histologic analysis revealed an intra-abdominal malignant seminoma with intraperitoneal and renal metastasis. Interestingly, a seminoma was also present in the descended testis of the draught horse.
First report of junctional epidermolysis bullosa (JEB) in the Italian draft horse. Epitheliogenesis imperfecta in horses was first recognized at the beginning of the 20th century when it was proposed that the disease could have a genetic cause and an autosomal recessive inheritance pattern. Electron microscopy studies confirmed that the lesions were characterized by a defect in the lamina propria and the disease was therefore reclassified as epidermolysis bullosa. Molecular studies targeted two mutations affecting genes involved in dermal-epidermal junction: an insertion in LAMC2 in Belgians and other draft breeds and one large deletion in LAMA3 in American Saddlebred. Metho...
Group C Streptococcus dysgalactiae subsp. equisimilis in south-east Brazil: genetic diversity, resistance profile and the first report of human and equine isolates belonging to the same multilocus sequence typing lineage. Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates are the most common group C streptococci in humans and reports of invasive infections associated with SDSE have been increasing. Molecular epidemiology studies are an important strategy to trace the emergence and spread of possible well-fit bacterial pathogens of humans and animals. In this work, we analysed the antimicrobial and clonal profiles of 115 SDSE infection and colonization isolates of human and equine origin. PFGE revealed the spread of two main clusters: clone A (57.4%) and clone A (26.1%). Remarkably, two isolates from ...
Molecular identification of Cryptosporidium spp. and Giardia duodenalis in grazing horses from Xinjiang, China. A total of 262 fecal specimens collected from grazing horses at five locations in Xinjiang, China were examined by PCR for Cryptosporidium spp. and Giardia duodenalis. The Cryptosporidium and G. duodenalis infection rates were 2.7% and 1.5%, respectively. Seven Cryptosporidium-positive specimens were found in foals (16.3%), and four G. duodenalis-positive specimens were found in mares (2.5%). Sequence analyses of 18S rRNA and gp60 genes revealed that seven animals were positive for the subtype VIaA15G4 of Cryptosporidium horse genotype. G. duodenalis assemblages A and B were identified by mole...
The efficacy of ELISA commercial kits for the screening of equine infectious anemia virus infection. The most used and reliable indicator of Equine infectious anemia virus (EIAV) infection is the detection of its specific antibodies in horse serum. In the present study, the performance of two commercial ELISA tests for the detection of EIAV antibodies as well as the potential advantages of their use as an EIAV infection screening tool were evaluated in 302 horse serum samples. Both ELISA assays showed 100% diagnostic sensitivity, and 92.3-94.3% diagnostic specificity. Discordant results were analyzed by immunoblot. The results showed that both ELISA tests are very efficient at detecting EIAV ...
Genetic diversity of Cryptosporidium spp. including novel identification of the Cryptosporidium muris and Cryptosporidium tyzzeri in horses in the Czech Republic and Poland. Faecal samples were collected from 352 horses on 23 farms operating under six different management systems in the Czech Republic and Poland during 2011 and 2012. Farms were selected without previous knowledge of parasitological status. All faecal samples were screened for Cryptosporidium spp. presence using microscopy, following aniline-carbol-methyl violet staining and PCR analysis of the small-subunit (SSU) rRNA and the 60-kDa glycoprotein (gp60) genes. Cryptosporidium muris-positive samples were additionally genotyped at four minisatellite markers: MS1 (encoding a hypothetical protein), MS2...
Whole-genome sequence analysis of G3 and G14 equine group A rotaviruses isolated in the late 1990s and 2009-2010. Equine group A rotavirus (RVA) G3P[12] and G14P[12] strains cause gastroenteritis in foals worldwide. Both of these strains have been co-circulating in Japan since G14P[12] strains emerged in the late 1990s. Although it is important to comprehensively understand the evolution of RVA strains, whole-genome sequence data on recent equine RVA strains in Japan are lacking. Therefore, in this study, whole-genome analysis of 23 equine RVA isolates from the late 1990s and 2009-2010 and the vaccine strain RVA/Horse-tc/JPN/HO-5/1982/G3P[12] (HO-5) was performed. The G3 strains, including strain HO-5, sh...
High genetic diversity of equine infectious anaemia virus strains from Slovenia revealed upon phylogenetic analysis of the p15 gag gene region. The equine infectious anaemia virus (EIAV), which belongs to the Retroviridae family, infects equids almost worldwide. Every year, sporadic EIAV cases are detected in Slovenia. Objective: To characterise the Slovenian EIAV strains in the p15 gag gene region phylogenetically in order to compare the Slovenian EIAV strains with EIAV strains from abroad, especially with the recently published European strains. Methods: Cross-sectional study using material derived from post mortem examination. Methods: In total, 29 EIAV serologically positive horses from 18 different farms were examined in this stu...
Anthrax as an example of the One Health concept. Anthrax is a peracute, acute or subacute multispecies bacterial infection that occurs on many continents. It is one of the oldest infectious diseases known; the biblical fifth and sixth plagues (Exodus chapters 7 to 9) that affected first livestock and then humans were probably anthrax. From the earliest historical records until development of an effective vaccine midway through the 20th Century, anthrax was one of the foremost causes of uncontrolled mortality in cattle, sheep, goats, horses and pigs, with 'spill over' into humans, worldwide. With the development of the Sterne spore vaccine, a...
A case of Murray Valley encephalitis in a 2-year-old Australian Stock Horse in south-east Queensland. This report summarises the findings from a case of naturally-occurring Murray Valley encephalitis in a 2-year-old filly presenting with acute onset of depression and weakness. Serum samples tested at the onset of clinical signs were negative for Hendra and Kunjin virus antibodies, but positive for Murray Valley encephalitis virus (MVEV) using IgM-capture ELISA (1 : 300 dilution). A virus neutralisation assay performed 4 weeks later confirmed a titre of 1 : 160. Sera collected in the weeks preceding neurological signs returned a negative titre for MVEV 2 weeks prior followed by a titre ...
Comparative evaluation of three surveillance systems for infectious equine diseases in France and implications for future synergies. It is necessary to assess surveillance systems for infectious animal diseases to ensure they meet their objectives and provide high-quality health information. Each system is generally dedicated to one disease and often comprises various components. In many animal industries, several surveillance systems are implemented separately even if they are based on similar components. This lack of synergy may prevent optimal surveillance. The purpose of this study was to assess several surveillance systems within the same industry using the semi-quantitative OASIS method and to compare the results of t...
PinR mediates the generation of reversible population diversity in Streptococcus zooepidemicus. Opportunistic pathogens must adapt to and survive in a wide range of complex ecosystems. Streptococcus zooepidemicus is an opportunistic pathogen of horses and many other animals, including humans. The assembly of different surface architecture phenotypes from one genotype is likely to be crucial to the successful exploitation of such an opportunistic lifestyle. Construction of a series of mutants revealed that a serine recombinase, PinR, inverts 114 bp of the promoter of SZO_08560, which is bordered by GTAGACTTTA and TAAAGTCTAC inverted repeats. Inversion acts as a switch, controlling the tra...
Eastern equine encephalitis: a classical case. We present the case of a 40-year-old man with rapidly deteriorating acute meningoencephalitis, finally diagnosed as eastern equine encephalitis (EEE). The course and timing in this patient are quite characteristic. EEE is an arthropod borneviral illness in which the mosquito serves as the vector. It is amongst the most severe of the arbovirus encephalitides and has a high mortality and morbidity. In nonfatal cases, residual neurological deficits are often severe and permanent. North American lineage of EEE is mainly found in the northeast especially along the coastal areas. EEE is primarily fo...
West Nile Virus Infection in Horses: Detection by Immunohistochemistry, In Situ Hybridization, and ELISA. This study describes the clinicopathologic findings in naturally occurring West Nile virus (WNV) infection in horses. WNV was diagnosed in a foal by immunohistochemical and in situ hybridization methods, and the presence of WNV antibodies was detected in 5 other horses with clinical signs suggestive of WNV infection. At necropsy of the foal, lymph nodes were edematous and enlarged, and the intestines showed diffuse congestion and focal hemorrhages. The most significant histologic lesions in this case were nonsuppurative meningoencephalomyelitis, particularly in the brainstem and spinal cord. I...
Rapid detection of equine coronavirus by reverse transcription loop-mediated isothermal amplification. A reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for the rapid detection of equine coronavirus (ECoV). This assay was conducted at 60 °C for 40 min. Specificity of the RT-LAMP assay was confirmed using several equine intestinal and respiratory pathogens in addition to ECoV. The novel assay failed to cross-react with the other pathogens tested, suggesting it is highly specific for ECoV. Using artificially synthesized ECoV RNA, the 50% detection limit of the RT-LAMP assay was 10(1.8)copies/reaction. This is a 50-fold greater sensitivity than conventio...
Mycobacterium bovis infection in a horse with granulomatous enterocolitis. A 2-year-old dappled Percheron horse had a wasting condition that did not respond to antibiotic treatments and ultimately resulted in death. Thickening of the wall of the large colon and enlargement of the mesenteric lymph nodes were observed at postmortem examination, along with the presence of pinpoint whitish foci in the liver. Microscopic examination of affected tissues revealed diffuse chronic granulomatous enterocolitis, granulomatous mesenteric lymphadenitis, and multifocal granulomatous hepatitis. The DNA extracted from paraffin-embedded intestinal and lymph node samples was analyzed u...
An outbreak of Arthroderma vanbreuseghemii dermatophytosis at a veterinary school associated with an infected horse. We report a case of an outbreak of inflammatory dermatophytoses caused by Arthroderma vanbreuseghemii (formally Trichophyton mentagrophytes pro parte) that involved an infected horse, the owner and at least 20 students, staff and stablemen at a veterinary school in Bern (Switzerland) that presented highly inflammatory dermatitis of the body and the face. Transmission from human to human was also recorded as one patient was the partner of an infected person. Both the phenotypic characteristics and ITS sequence of the dermatophytes isolated from the horse and patients were identical, consistent ...
Hendra virus survival does not explain spillover patterns and implicates relatively direct transmission routes from flying foxes to horses. 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...
Structural characterisation of the virulence-associated protein VapG from the horse pathogen Rhodococcus equi. Virulence and host range in Rhodococcus equi depends on the variable pathogenicity island of their virulence plasmids. Notable gene products are a family of small secreted virulence-associated proteins (Vaps) that are critical to intramacrophagic proliferation. Equine-adapted strains, which cause severe pyogranulomatous pneumonia in foals, produce a cell-associated VapA that is necessary for virulence, alongside five other secreted homologues. In the absence of biochemical insight, attention has turned to the structures of these proteins to develop a functional hypothesis. Recent studies have ...
Freedom from equine infectious anaemia virus infection in Spanish Purebred horses. No cases of equine infectious anaemia (EIA) have been reported in Spain since 1983. Factors that could increase the risk of reintroducing equine infectious anaemia virus (EIAV) into Spain include the recent occurrence of the disease in Europe and the absence of compulsory serological testing before importation into Spain. Objective: Given the importance of the Spanish Purebred (SP) horse breeding industry in Spain, the aim of this cross-sectional study was to provide evidence of freedom from EIAV in SP stud farms in Central Spain. Methods: Serum samples from 555 SP horses, collected between Se...
An update on Sarcocystis neurona infections in animals and equine protozoal myeloencephalitis (EPM). Equine protozoal myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treat...
Emergence of Equine West Nile Encephalitis in Central Macedonia, Greece, 2010. During the summer of 2010, an outbreak of West Nile virus (WNV) infections attributed to a lineage 2 WNV strain was reported among humans and horses in Central Macedonia, Northern Greece. Here, the clinical and laboratory investigation of horses that showed severe neurological signs due to WNV infection is being described. Specifically, between August and September 2010, 17 horses with neurological signs were detected. WNV infection was confirmed in all 17 clinical cases by applying laboratory testing. The duration of WNV-specific IgM antibodies in sera obtained from seven of the clinically af...
Occurrence of antibodies against Toxoplasma gondii and its isolation and genotyping in donkeys, mules, and horses in Brazil. The occurrence of antibodies against Toxoplasma gondii was determined in donkeys, mules, and horses from different regions of Brazil. Serum samples from 304 donkeys (67.11%), 118 horses (26.05%), and 31 mules (6.84%) were analyzed by means of the indirect fluorescent antibody test (cutoff=64). Antibodies against T. gondii were detected in 129 equids (28.47%) (82 donkeys, 32 horses, and 15 mules). Tissue samples from 19 seropositive and 50 seronegative animals were obtained in order to isolate the parasite by means of mouse bioassay, and T. gondii was isolated from a donkey. Through genotypic c...
Necrotizing Enteritis and Hyperammonemic Encephalopathy Associated With Equine Coronavirus Infection in Equids. Equine coronavirus (ECoV) is a Betacoronavirus recently associated clinically and epidemiologically with emerging outbreaks of pyrogenic, enteric, and/or neurologic disease in horses in the United States, Japan, and Europe. We describe the pathologic, immunohistochemical, ultrastructural, and molecular findings in 2 horses and 1 donkey that succumbed to natural infection with ECoV. One horse and the donkey (case Nos. 1, 3) had severe diffuse necrotizing enteritis with marked villous attenuation, epithelial cell necrosis at the tips of the villi, neutrophilic and fibrinous extravasation into th...
