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Topic:Epidemiology
Epidemiology in horses involves the study of the distribution and determinants of health-related states and events in equine populations. It encompasses the investigation of patterns, causes, and effects of diseases and health conditions within horse populations. This field of study aims to identify risk factors for disease and targets for preventive healthcare. Key components of equine epidemiology include disease surveillance, outbreak investigation, and the study of disease dynamics within herds or regions. Research in this area often focuses on infectious diseases, zoonotic diseases, and the impact of environmental factors on equine health. This page compiles peer-reviewed research studies and scholarly articles that explore various aspects of epidemiology in horses, including disease prevalence, transmission pathways, and strategies for disease prevention and control.
Jean-François Bouley (Bouley jeune). Pioneer investigator in intermittent claudication. Reports of pathologic investigations as to the cause of intermittent claudication in horses were made in France in October, 1831, by veterinarian Jean-François Bouley. Obstructive clots in the femoral arteries were found to be responsible for the muscular changes causing limping. Bouley's work in the horse was used by Charcot in 1858 to understand the mechanism of claudication in the case of a soldier with gunshot wound in whom a traumatic aneurysm, clotting, and ischemia of the legs developed. This was not, however, the first medically reported case of human claudication from vascular occlus...
Echinococcus granulosus (Taeniidae) and autochthonous echinococcosis in a North American horse. We report the first documented case of autochthonous echinococcosis in a horse of North American origin. Three fully mature and viable unilocular hydatid cysts of Echinococcus granulosus (Batsch, 1786) were an incidental finding at necropsy in the liver of a 14-yr-old gelding thoroughbred that had been foaled in Virginia and raised in Maryland. Protoscolices were armed with 2 rows of 28-37 rostellar hooks; small hooks measured 23-30 microns; large hooks measured 26-33 microns. Morphologically, these were compatible with rostellar armature considered typical for the equine strain of E. granulos...
Enterolithiasis in two zebras. Enterolithiasis, as a cause of colic, was diagnosed and treated during surgical intervention in 2 Grant's zebras (Equus burchelli bohmi). The zebras were part of a wild herd in a zoo in the western United States. The clinical signs of enterolithiasis in both zebras were similar to those reported for horses. Analysis of the enterolith from 1 zebra revealed a composition identical to enteroliths that have been analyzed from horses. Three other zebras from this herd had enteroliths at necropsy. Enterolithiasis should be considered as a differential diagnosis for zebras with low-grade obstructive ...
Characterization of A/eq-1 virus isolated during the equine influenza epidemic in India. The equine influenza virus, Ludhiana/5/87, isolated from the clinical material during the epidemic of equine influenza in India in 1987 was inhibited in haemagglutination-inhibition test by the antiserum against the prototype A/eq/Prague/1/56 (H7N7) virus and by post-epidemic horse sera. In haemagglutinin and neuraminidase analysis, the A/eq/Ludhiana/5/87 isolate appeared similar to the prototype A/eq/Prague/1/56 virus and was characterized as the H7N7 subtype.
Diagnosis of the African horse sickness virus serotype 4 by a one-tube, one manipulation RT-PCR reaction from infected organs. A single tube reverse transcription-polymerase chain reaction (RT-PCR) method for detection of African horse sickness virus (AHSV) in splenic tissues from infected horses is described. Double stranded RNA was extracted from infected organs of horses and used to produce complementary DNA (cDNA) with the two primers selected for the PCR. The 1179 bp amplified product (the segment 7 which encodes for VP 7), detected by electrophoresis on agarose gel and ethidium bromide staining, was hydrolysed with eight restriction endonucleases for characterization of the AHSV. The sensitivity of this method i...
[An outbreak of equine arteritis virus infection in a riding school]. A major part of the residing horses and ponies of a riding school in Noord-Holland became affected by a febrile disorder that included anorexia, depression, conjunctivitis, urticaria, edema of the legs and laborious locomotion. All remaining horses fell ill within one week. Based on the clinical symptoms the disorder was diagnosed as vasculitis. With serology the causative agent of the disorder appeared to be equine arteritis virus.
Prevalence and factors associated with development of laminitis in horses with duodenitis/proximal jejunitis: 33 cases (1985-1991). Medical records of 116 horses admitted to the Texas Veterinary Medical Center between Jan 1, 1984 and Dec 31, 1991 with duodenitis/proximal jejunitis (DPJ) were reviewed. The prevalence of laminitis was 28.4% (33/116; 95% confidence interval: 20.2 to 36.6%). The prevalence of DPJ and DPJ-associated laminitis did not appear to vary significantly by year during the study period. Anamnesis, physical examination, clinicopathologic data, and initial treatment recorded at the time of admission were reviewed to determine risk factors associated with development of laminitis associated with DPJ. A tre...
Epidemiology of equine motor neuron disease. Equine motor neuron disease (EMND) is a newly recognized neurodegenerative disorder of bulbospinal motor neurons in the horse. We conducted a case-control study to identify intrinsic factors associated with the risk of this disorder. Seventy-four cases and 160 controls were assembled. Controls included horses diagnosed with equine protozoal myelitis, equine degenerative myeloencephalopathy, and cervical stenotic myelopathy during the same time period as the cases. Logistic regression analysis was used to evaluate the association of each hypothesized factor while simultaneously controlling for ...
Is horse riding a dangerous recreation for young girls? A study at emergency departments of Lahti City Hospital and Päijat-Häme Central Hospital, Lahti. Horse-related injuries form a notable part of sports and leisure time accidents. 54% of the injured were female riders under the age of 20 years. The most serious injuries were upper extremity ones. Over one third of the riders had suffered previously from horse-related injuries.
[Trichinellosis in slaughtered and wild animals in Switzerland using a digestion method and a serologic method (E/S-ELISA)]. For many decades trichinellosis has not been reported among Swiss domestic pigs. Considering the fact that Trichinella occurs in a sylvatic cycle in Switzerland, a study was designed to reevaluate the present epidemiologic situation by investigating 10,904 fattening pigs, 218 pigs with free access to pasturage or being kept on an alp, 104 domestic boars, 106 horses, 44 wild boars and 538 foxes using a direct and an indirect diagnostic technique (digestion method and serology with ELISA and an excretory/secretory antigen, respectively). The digestion method was performed according to EC-guideli...
Evolution of alphaviruses in the eastern equine encephalomyelitis complex. Evolution of viruses in the eastern equine encephalomyelitis (EEE) complex was studied by analyzing RNA sequences and oligonucleotide fingerprints from isolates representing the North and South American antigenic varieties. By using homologous sequences of Venezuelan equine encephalomyelitis virus as an outgroup, phylogenetic trees revealed three main EEE virus monophyletic groups. A North American variety group included all isolates from North America and the Caribbean. One South American variety group included isolates from the Amazon basin in Brazil and Peru, while the other included strain...
The development of Babesia (Theileria) equi (Laveran, 1901) in the gut and the haemolymph of the vector ticks, Hyalomma species. The development of the piroplasm Babesia equi was studied by light microscopy in the gut and the haemolymph of three different Hyalomma species during and after the nymphs had engorged on parasitaemic horses. The stock of B. equi used was isolated from a horse imported from Turkmenistan (CIS) in 1991. The existence of gamogony was identified by the occurrence of gamonts and gametes in the gut contents of the nymphs at between 3 and 4 days after infestation of the nymphs, before the ticks dropped off the experimentally infected horses. Zygotes and kinetes were observed in the intestinal cells f...
[Rhinopneumonia and equine viral arteritis: seroepidemiological study in the northeast of Tunisia]. A seroepidemiological survey was realized in the Nord-Est Tunisia to study the prevalence of complement fixing and neutralizing antibodies to equine rhinopneumonitis and viral arteritis of horse, respectively. Four hundred sera were tested, using complement fixation reaction and seroneutralization test. The results show that 8.75% of sera have antibodies to viral arteritis and only 1.25% are positive for equine rhinopneumonitis.
The frequent occurrence of thyroid tumours in aged horses. Thyroid tumours have been described as "moderately common" in horses, but diseases associated with them are rare and the actual incidence has not been reported. A survey of thyroids from 29 horses aged 12 to 32 years revealed gross lesions in 11 animals, all older than 17. Most lesions were microfollicular adenomas. There was no evidence that the horses suffered from long-standing iodine deficiency or diffuse hyperplasia. Adenomas were more common than hyperplastic nodules and it is unlikely that the former arose from the latter. One thyroid adenocarcinoma was discovered. Progression from thyr...
[The genital microflora in the stallion–microbiological study of presecretion samples from 1972 to 1991]. From 1972 to 1991, presecretion on an average of 183 stallions per year had been examined. Facultatively pathogenic germs were ascertained in 13.5% of the samples. However, the portion showed considerable annual fluctuation, as did the percentage of the different kinds of germs. In most of the cases, only minimal growth had been observed in culture. Except for the total percentage, these results are contradictory to those we found during the examination of cervical swabs of mares. In order to ascertain the importance of the respective results and to render possible a correct interpretation, th...
Diagnosis of equine influenza by the polymerase chain reaction. Influenza A is a common respiratory infection of horses, and rapid diagnosis is important for its detection and control. Sensitive detection of influenza currently requires viral culture and is not always feasible. The polymerase chain reaction (PCR) was used to detect DNA produced by reverse transcription of equine influenza in stored nasal secretions, vaccines, and allantoic fluids. Primers directed at a target of 212 bp on conserved segment 7 (matrix gene) of human influenza A/Bangkok/1/79(H3N2) produced amplification products of appropriate size with influenza A/Equine/Prague/1/56 (H7N7), ...
Diagnosis of eastern equine encephalomyelitis virus infection in horses by immunoglobulin M and G capture enzyme-linked immunosorbent assay. Immunoglobulin M (IgM) and G (IgG) capture enzyme-linked immunosorbent assays (ELISAs) were used as possible adjuncts to hemagglutination inhibition (HI) and virus neutralization (VN) tests to differentiate between reaction to recent exposure to eastern equine encephalomyelitis (EEE) virus and those due to prior vaccination. Serum samples were evaluated by the IgM-capture ELISA, and the results were compared with those of HI and VN tests. Of 381 serum samples, 51% (195 samples) were positive by HI test (> or = 1:40) and 54% (205 samples) were positive by VN test (> or = 1:10), but only 3...
Inter- and intra-strain genomic variation in equine herpesvirus type 1 isolates. Restriction enzyme digests of DNA from 22 unselected isolates of EHV-1 were analysed by hybridization with cloned DNA fragments covering the genome. In addition to a small amount of inter-strain variation, heterogeneity within strains was observed, caused by loss of specific restriction endonuclease sites in the DNA of a proportion of the virus particles of any one stock. Fifteen strains demonstrated the same intra-strain variation involving loss of the BamHI L-M site which was shown to lie within coding sequence for the large subunit of ribonucleotide reductase. This particular mutation may t...
Medically important arboviruses of the United States and Canada. Of more than 500 arboviruses recognized worldwide, 5 were first isolated in Canada and 58 were first isolated in the United States. Six of these viruses are human pathogens: western equine encephalitis (WEE) and eastern equine encephalitis (EEE) viruses (family Togaviridae, genus Alphavirus), St. Louis encephalitis (SLE) and Powassan (POW) viruses (Flaviviridae, Flavivirus), LaCrosse (LAC) virus (Bunyaviridae, Bunyavirus), and Colorado tick fever (CTF) virus (Reoviridae, Coltivirus). Their scientific histories, geographic distributions, virology, epidemiology, vectors, vertebrate hosts, transm...
Epidemiology of equine Cryptosporidium and Giardia infections. Prevalence and infection patterns of Cryptosporidium and Giardia infections in horses were studied by a direct immunofluorescence staining method. Faecal examinations of 222 horses of different age groups revealed Cryptosporidium infection rates of 15-31% in 66 foals surveyed in central Ohio, southern Ohio and central Kentucky, USA. Only 1 of 39 weanlings, 0 of 46 yearlings, and 0 of 71 mares were positive. Giardia infection was found in all age groups, although the infection rates for foals were higher (17-35%). Chronological study of infection in 35 foals showed that foals started to excrete...
[Seroepidemiological survey of influenza and infectious anemia in Equidae in northeastern Tunisia]. Using the haemagglutination inhibition and immunodiffusion tests, a national serological survey was carried out to detect antibodies to equine influenza (EI) (A/equi/1/Prague 56 and A/equi/2/Miami 63) and equine infectious anaemia (EIA) in horse sera collected in northeastern Tunisia. 533 samples were analysed for EIA antibodies. All were negative. 13.6% of 433 equine sera tested for EI antibodies were positive. These results are discussed and compared with others obtained in Tunisia and bordering countries.
Preventive administration of bovine colostral immunoglobulins for foal diarrhea with rotavirus. Foal diarrhea due to serotype 3 rotavirus broke out on a foal-raising farm in the years 1987 and 1989. In 1989, all of the foals, regardless of whether or not they suffered from diarrhea, received bovine colostral immunoglobulin (Ig) powder orally for 3 to 5 days during the epidemic. The morbidity of the diarrhea was lower than that observed in 1987, when the Ig powder was not administered to foals. These data suggested that the administration of Ig powder might partially prevent foal diarrhea with rotavirus infection.
Equine plasminogen polymorphism: allelic frequencies in 23 breeds. A modified procedure for detection of the two alleles of equine plasminogen using Western blotting methods following polyacrylamide gel isoelectric focusing is described. Gene frequencies in 23 breeds and Equus przewalskii are provided.
Eastern equine encephalitis (EEE): a description of the 1989 outbreak, recent epidemiologic trends, and the association of rainfall with EEE occurrence. An Eastern equine encephalitis (EEE) outbreak in 1989 led to nine human and 196 equine cases, chiefly in coastal Atlantic and Gulf Coast counties. In the past two decades, EEE age-specific incidence and mortality rates have declined compared with earlier years. Analysis of rainfall patterns in areas where human EEE cases occurred between 1983 and 1989 revealed an association between occurrence of human cases and excess rainfall. The association was stronger with data from local weather stations than from statewide rainfall averages and the predictive models were best when applied to northern s...
A rapid diagnostic assay for eastern equine encephalomyelitis viral RNA. Eastern equine encephalomyelitis virus (EEEV) has been a low-frequency, but serious human and veterinary health problem. Increased frequency of this mosquito-borne virus is anticipated as wetlands are maintained and re-established. Control of EEEV has depended on mosquito abatement in response to increasing frequency of EEEV in the environment. A coupled reverse transcription/polymerase chain reaction assay was designed to rapidly, sensitively, and specifically detect EEEV RNA. The assay successfully detected the viral RNA in a single-blind study of a set of field samples composed of either po...
The outbreak of equine influenza (H3N8) in the United Kingdom in 1989: diagnostic use of an antigen capture ELISA. In July 1989 influenza A/equine-2 (H3N8) was isolated from a nasopharyngeal swab taken from a non-thoroughbred horse exhibiting acute clinical respiratory disease. This was the first isolation of equine influenza virus in the United Kingdom since 1981. Subsequent investigations of acute respiratory disease in horses indicated that the infection was dispersed throughout the UK. However, unlike the previous epidemic of 1979, the first horses from which the virus was isolated had been vaccinated. This outbreak of influenza provided an opportunity to evaluate an antigen capture ELISA, directed aga...
