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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.
Benefit-cost analysis of vaccination of horses as a strategy to control equine monocytic ehrlichiosis. To determine whether horses in New York should be vaccinated against equine monocytic ehrlichiosis (EME). Methods: Decision-tree analyses of data from a cross-sectional study and a case-control study. Methods: Horses in New York. Methods: Annual expected monetary loss per horse attributable to EME was calculated for vaccinated and nonvaccinated horses in New York. Because risk of being seropositive was dependent on county in which the horse was located, farm elevation, and use of each horse, decision-tree analyses were stratified by these factors. Results: Annual expected monetary loss per hor...
Assessment of the effect of three treatments to remove intrauterine fluid on pregnancy rate in the mare. The effects on pregnancy rate of three different treatments to remove intrauterine fluid were assessed in 1267 mares. The mares were mated and allocated, in strict rotation, to four treatment groups: 1) untreated controls, 2) intrauterine infusion of broad spectrum antibiotics, 3) intravenous injection of oxytocin, 4) intravenous injection of oxytocin followed by intrauterine antibiotics. The pregnancy status of the mares was determined 13 to 15 days and 27 to 30 days after ovulation by transrectal ultrasonography. The pregnancy rate of group 4 (72 per cent) was higher than that of group 2 (64...
Adverse drug reactions: report of the Australian Veterinary Association Adverse Drug Reaction Subcommittee, 1994. Seventy-seven reports of suspected adverse drug reactions (ADRs) were received by the Adverse Drug Reaction Subcommittee (ADRSc) of the Australian Veterinary Association from April 1993 to December 1994 inclusive. The number of reports received/number of animals involved per species were: dogs (32/44), cats (18/31), horses (17/48), and cattle (10/21). Of these, 49 (64%) were classified as definite ADRs and 9 (12%) as probable ADRs. In 11 (14%) reports an ADR could not be substantiated or there was insufficient information available to make a decision. Eight reports were not classified because ...
Methods for the Detection of Trichinellosis in Horses. Twelve horses were infected with various doses of Trichinella spiralis and then tested for infection using direct (artificial digestion) and indirect (enzyme immunoassay) methods. Horses became infected in a dose-dependent manner. Larvae accumulated preferentially in the tongue, followed by the masseter, neck, supraspinatus, trapezius, and diaphragm. At lower infection levels, the tongue harbored several times more parasites than were found in other tissues. The sensitivity of artificial digestion methods for detecting infections was directly related to sample size. One-gram samples were not r...
Antigenic and genetic evolution of equine H3N8 influenza A viruses. Evolution of equine influenza a H3N8 viruses was examined by antigenic and genetic analysis of a collection isolates from around the world. It was noted that antigenic and genetic variants of equine H3N8 viruses cocirculate, and in particular that variants currently circulating in Europe and the USA are distinguishable from one another both in terms of antigenic reactivity and genetic structure of the HA1 portion of the haemagglutinin (HA) molecule. Whilst the divergent evolution of American and European isolates may be due to geographical isolation of the two gene pools, some mixing is believ...
Horseback-riding-associated traumatic brain injuries–Oklahoma, 1992-1994. Each year, traumatic brain injury (TBI) is associated with 52,000 deaths and accounts for one third of all injury deaths in the United States; in addition approximately 80,000 persons who survive TBI incur some loss of function, residual disability, and increased medical-care needs because of these injuries. Major causes of TBI are motor-vehicle crashes, falls, assaults, and sports and recreational activities. During 1992-1993 in Oklahoma, horseback riding was the leading cause of sports-related TBI. To further characterize horseback-riding-associated TBIs, the Oklahoma State Department of Hea...
Comparison of the reappearance of strongyle eggs on foals, yearlings and adult horses after treatment with ivermectin or pyrantel. The reappearance of strongyle eggs in faeces after treatment with ivermectin or pyrantel embonate was investigated in 22 foals, 36 yearlings, and 45 adult horses on five Dutch horse farms. The results confirmed earlier studies which showed an egg reappearance period of 9 and 6 weeks after ivermectin and pyrantel treatment, respectively. There were no differences between the egg reappearance periods of foals, yearlings, and adult horses. The mean egg counts of the yearlings were, however, consistently higher than the mean egg counts of the adult horses and foals in both ivermectin- and pyrantel...
Anomalous inheritance of a paternally derived trophoblast antigen. Recurrent spontaneous abortion occurs in 1 in 500 random matings and usually results in abortion of all pregnancies. If absence of antibody to a paternally derived antigen caused abortion, the woman would be expected to make antibody to the other paternal antigen and abort only half her pregnancies. Methods: Microvesicles were prepared from equine placentae. Acid-eluted IgG antibody was eluted from the polymorphic R80K antigen and used to type the residual R80K antigen on vesicles or on peripheral blood leucocytes. Results: In several equine sibships all the half-sibs had the same paternal R80...
Evaluation of travel and use as a risk factor for seropositivity to Ehrlichia risticii in horses of New York state. To determine whether mean annual frequency and destination of equine travel was associated with exposure to Ehrlichia risticii and whether these associations were modified by horses' place of residence. Methods: Cross-sectional study. Methods: 511 equine operations containing 2,587 horses were visited in New York state from a target population of 39,000 operations. Methods: Each horse was tested for serum antibodies against E risticii, using indirect fluorescent antibody. Information on the horse's travel history, farm's management practices, and surrounding ecology was obtained by personal in...
Cross-sectional evaluation of environmental, host, and management factors associated with risk of seropositivity to Ehrlichia risticii in horses of New York state. To locate counties within New York state with a high seroprevalence among the equine population, to determine host, management, and environmental factors that were associated with seropositivity to Ehrlichia risticii, and to determine evidence for arthropod- or helminth-mediated transmission of E risticii to horses. Methods: Cross-sectional study. Methods: A random sample of 3,000 of the 39,000 equine operations in New York state was selected, and 2,587 horses from 511 operations were tested. Methods: Blood samples were collected from horses and tested for seropositivity, using the indirect fl...
Alterations in the equine herpesvirus type-1 (EHV-1) strain RacH during attenuation. The equine herpesvirus type-1 modified live-vaccine strain RacH (256th passage on porcine embryonic kidney cells) was investigated by restriction-enzyme analysis and compared to representative plaque isolates of the 12th passage (RacL11, RacL22) and 185th passage (RacM24, RacM36). The restriction patterns of all Rac plaque isolates differed compared with reference strain Ab4. The left UL terminus was shortened by 0.1 kbp and a missing BamHI site led to the fusion of the f and t fragments. In some Rac derivatives, losses of restriction sites without deletions were observed: 1. One BamHI site lo...
Prevalence of sarcocysts in livestock of northwest Ethiopia. A survey of Sarcocystis was conducted in cattle, sheep, goats, donkeys and chickens. A total of 671 haematoxylin-eosin (H-E) stained muscle tissue samples, including diaphragm, masseter, cardiac and oesophageal musculatures were examined. Additionally, cardiac muscle samples from 40 fetuses were included. An infestation rate of 93% in sheep, 82% in cattle, 81% in goats, 16.6% in donkeys and 6.6% in chickens was noted. The infestation rate of diaphragm, masseter, cardiac and oesophageal musculatures seems to be similar. None of the 40 fetal heart muscle samples from bovine, ovine, caprine and d...
Risk factors for history of previous colic and for chronic, intermittent colic in a population of horses. To identify risk factors for recurrent colic and chronic, intermittent colic in horses. Methods: Case control study. Methods: The population included 768 horses examined by veterinarians for emergencies other than colic (control group). Methods: Horses with colic that had history of colic (n = 232) were compared with those without such history (n = 536), using logistic regression analysis to identify risk factors for history of previous colic and to determine odds ratios (OR) for these associations. Among the 232 horses in the history of colic group, 58 horses that had chronic, intermittent co...
Accidents with horses: what has changed in 20 years? Horse riding is a dangerous pastime with more accidents occurring per hour than during motor-cycling. Since a prospective survey of horse-related injuries conducted at a major centre in 1971-1972, equestrian groups and the medical profession have encouraged improvements in training and protective riding wear. By conducting a similar study at the same centre 20 years later we hoped to assess the effects of these measures on the pattern of injuries resulting from contact with horses. Patient and injury details were recorded prospectively for all those presenting to the Accident Service at Oxford...
Risk factors associated with the incidence of foal mortality in an extensively managed mare herd. The purpose of this study was to determine the incidence of neonatal mortality in a large, extensively managed mare herd and what risk factors were involved in foal mortality. For a 6 wk period between April 18, 1994, and May 31, 1994, 334 foals were born, of which 74 died before reaching 10 d of age, giving an overall mortality of 22% for this period. Seventy four percent of the foal deaths occurred within 48 h of parturition. The major causes of foal mortality included starvation/exposure 27%, septicemia 26%, and dystocia 20%. Weekly incidences varied significantly, ranging from 67% for week...
Correlation between DNA restriction fragment length polymorphisms in Leptospira interrogans serovar pomona type kennewicki and host animal source. Isolates (n = 147) of Leptospira interrogans serovar pomona type kennewicki from cattle, swine, horses, and wildlife were analyzed by DNA restriction endonuclease analysis. Restriction fragment length polymorphisms were identified in DNA digested with HpaII, and the restriction fragment length polymorphisms were correlated with the host animal source of the isolates. These results will be useful in understanding the epidemiology of serovar pomona infections in livestock.
Intestinal ciliates found in the feces of Japanese native Tokara pony, with the description of a new genus and a new species. The composition of intestinal ciliates excreted in the feces of 20 Tokara native ponies kept in Iriki farm of Kagoshima University was surveyed. Eleven genera consisting of 18 species were identified based on the description of Strelkow. One new genus including a new species, Wolskana tokarensis n. gen., n. sp., of the family Buetschliidae was recognized and described. The average ciliate density of all horses was 13.8 x 10(3)/ml. Those of stallions (n = 5), mares (n = 11) and foals (n = 4) were 3.9, 16.1 and 43.3 x 10(3)/ml respectively. The value of stallions was significantly lower and that...
[Spectrum of species and incidence of endoparasites in foals and their mother mares from breeding farms with and without anthelmintic prophylaxis in upper Bavaria]. In this epidemiological study 37 foals and mares were included, which have been coproscopically examined in regular intervals over a period lasting up to 13 months. The animals derived from nine breeding farms. In three of these farms no anthelmintics were used before this investigation, whereas in six farms at least three years before regular prophylactic treatments with anthelmintics have been carried out. This investigation revealed no differences in the species spectrum of endoparasites as well as in the incidence of infections as regards to the breeding farms with and without anthelmintic...
Chronic obstructive pulmonary disease in horses in Louisiana. To evaluate chronic obstructive pulmonary disease of horses in Louisiana by assessing the signalment, history, environmental factors, clinical signs, and treatment of such horses. Methods: Epidemiologic mail survey. Methods: 83 of 240 veterinarians contacted by mail agreed to take part in the survey. Veterinarians contacted were listed as mixed-animal or equine practitioners in the 1991/1992 directory of the Louisiana Veterinary Medical Association or had submitted a specimen from a horse to the Louisiana Veterinary Medical Diagnostic Laboratory within the past 2 years. Methods: The survey con...
Occupational Exposures and Risks of Spontaneous Abortion among Female Veterinarians. Associations between occupational exposures and spontaneous abortion (SA) in a cohort of female veterinarians were studied with pregnancy and job-exposure history data collected as part of a mixed-mode survey of all women graduating from U.S. veterinary colleges during the 11-year period 1970-1980 (N = 2,997; response rate 85.0%). Data analysis focused on SA risks among postgraduation pregnancies in relation to 1) type of clinical practice at the time of conception and 2) self-reported occupational exposures to 13 exposure entities. Multiple logistic regression was used to control for the pote...
[Occurrence of Parascaris equorum in foals and adult horses under different breeding conditions]. Autopsies and analyses of faecal samples from working horses have shown common occurrence of ascarids in foals, whereas 19.6% of adult horses have been found infected. No influence of season on EPG in adult horses has been found. Study based on faecal samples from stud horses has shown that 5-6-month old animals were most susceptible to the infection. 50% of foals have been found infected in spite of deworming with the use of bezimidazole compounds. It has been stated that the proper dose of an anthelminthic is a basic problem in the control of ascarids.
Nationwide serological survey of equine influenza in Nigeria. The objective of this work was to examine the incidence of equine influenza viruses in the equine population of an area of tropical Africa where equine influenza virus activity has recently been reported for the first time. A serological survey of sera from horses and donkeys from regions of Nigeria taken from 1990 to 1993 was carried out and the results obtained were com-pared with equine sera from Western Europe (Ireland). The sera were assayed for presence of antibodies by both haemagglutination inhibition (HI) and ELISA using a monoclonal antibody to the prototype H3 equine influenza virus...
Rapid diagnosis of African horse sickness. The rapid diagnosis of African horse sickness (AHS) during the incubation period using virus antigens in peripheral blood mononuclear cells (PBMC) and red blood cells (RBC) in a sandwich indirect enzyme-linked immunosorbent assay (ELISA) is reported. PMBC consistently gave higher positive ELISA results than RBC from blood collected during viraemia from clinically affected horses. The potential of the method described for wider application in rapid diagnosis and virus surveillance in susceptible equine populations, particularly in AHS-free and in enzootic areas, for effective control strategies...
Differences between Taylorella equigenitalis strains in their invasion of and replication in cultured cells. The ability of Taylorella equigenitalis, the causative agent of contagious equine metritis, to invade and replicate in equine derm cells was studied. The kinetics of invasion and replication were determined for four T. equigenitalis strains. On the basis of these experiments, a simpler assay in which the invasive as well as the replicative properties of a particular strain could be determined was developed. This assay was used to characterize 32 strains, which had previously been typed by field inversion gel electrophoresis of genomic restriction fragments. The invasiveness of T. equigenitalis...
The effect of arthritis in the carpal joint on performance in Norwegian cold-blooded trotters. The purpose of this study was to evaluate the impact of arthritis of the carpal joint on performance of Norwegian cold-blooded trotters. Two performance variables were used in the analyses. The first was the start status, for which horses that had started in one or more races within a certain age received the value 1, and horses that had not raced were correspondingly assigned the value 0. The second variable was the accumulated, transformed and standardized earnings (ATSE), which is the power transformation of earnings (earnings .2, with unraced horses assigned a value of zero) expressed as a...
Ixodes pacificus (Acari: Ixodidae) as a vector of Ehrlichia equi (Rickettsiales: Ehrlichieae). Ehrlichia equi, a rickettsia described from horses in California 30 yr ago, causes equine granulocytic ehrlichiosis throughout the Americas and possibly Europe. Here, we report experimental transmission of E. equi from infected to susceptible horses through bites of western blacklegged ticks, Ixodes pacificus (Cooley & Kohls). In preliminary field studies, only I. pacificus consistently infested horses and vegetation at 3 locations with contemporary cases of equine ehrlichosis, and in particular, I. pacificus was the only species found attached to all of the infected horses. Exposure to bites ...
