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Topic:Disease Transmission
Disease transmission in horses refers to the spread of infectious agents such as bacteria, viruses, fungi, and parasites among equine populations. These pathogens can be transmitted through various routes, including direct contact, vector-borne transmission, or environmental exposure. Factors influencing disease transmission include horse density, management practices, and biosecurity measures. Understanding the mechanisms and conditions that facilitate the spread of diseases is essential for developing effective prevention and control strategies. This page compiles peer-reviewed research studies and scholarly articles that investigate the modes of transmission, risk factors, and management practices related to infectious diseases in horses.
Recent advances in molecular epidemiology and detection of Taylorella equigenitalis associated with contagious equine metritis (CEM). In the present review article, recent molecular advances relating to studies with Taylorella equigenitalis, as well as the recently described second species of the genus Taylorella, namely Taylorella asinigenitalis, have been described. Molecular genotyping of T. equigenitalis strains by pulsed-field gel electrophoresis (PFGE) after digestion with the suitable restriction enzyme(s) enabled the effective discrimination of strains, thus allowing the examination of the scientific mechanism(s) for its occurrence and transmission of contagious equine metritis (CEM). Alternatively, polymerase chain ...
Digenetic trematodes, Acanthatrium sp. and Lecithodendrium sp., as vectors of Neorickettsia risticii, the agent of Potomac horse fever. Neorickettsia (formerly Ehrlichia) risticii, the agent of Potomac horse fever (PHF), has been recently detected in trematode stages found in the secretions of freshwater snails and in aquatic insects. Insectivores, such as bats and birds, may serve as the definitive host of the trematode vector. To determine the definitive helminth vector, five bats (Myotis yumanensis) and three swallows (Hirundo rustica, Tachycineta bicolor) were collected from a PHF endemic location in northern California. Bats and swallows were dissected and their major organs examined for trematodes and for N. risticii DNA...
Lateral transmission of equine arteritis virus among Lipizzaner stallions in South Africa. A serological study conducted in 1995 revealed that 7 stallions at the Lipizzaner Centre, Gauteng, South Africa, were seropositive for antibody to equine arteritis virus (EAV). A Lipizzaner stallion imported into South Africa from Yugoslavia in 1981 had previously (1988) been confirmed to be an EAV carrier. Despite being placed under life-long breeding quarantine, EAV had been transmitted between stallions at the Lipizzaner Centre. Objective: To investigate the phylogenetic relationships between the strain of EAV shed in the semen of the original carrier stallion and strains recovered from the...
Small-world topology of UK racing: the potential for rapid spread of infectious agents. The topology of the network of contacts between individuals has important effects on infectious disease dynamics within a population. Here we examine for the first time a network of contacts between training yards that occurred through racing. Objective: To explore the topology of this network and to consider the effects of the network on the potential for disease transmission. Methods: Race data from one week was analysed. Contacts were defined as occurring between trainers that raced horses in the same race and hence one trainer could contact another trainer several times. A connection was s...
Case-control study of factors associated with fibrinous pericarditis among horses in central Kentucky during spring 2001. To identify factors significantly associated with an epidemic of fibrinous pericarditis during spring 2001 among horses in central Kentucky. Methods: Case-control study. Methods: 38 horses with fibrinous pericarditis and 30 control horses examined for other reasons. Methods: A questionnaire was developed to solicit information regarding a wide range of management practices and environmental exposures from farm owners or managers. Results: The following factors were found in bivariate analyses to be significantly associated with an increased risk of pericarditis: being from a farm with mares an...
Surveillance results from the first West Nile virus transmission season in Florida, 2001. After West Nile virus (WNV) was first detected in Florida in July 2001, intensive surveillance efforts over the following five months uncovered virus activity in 65 of the state's 67 counties with 1,106 wild birds, 492 horses, 194 sentinel chickens, and 12 people found infected with the virus. Thirteen of 28 mosquito isolations came from Culex mosquitoes. As seen in the northeastern United States, wild bird mortality was the most sensitive surveillance method. However, unlike the predominantly urban 1999 and 2000 epizootics, the Florida transmission foci were rural with most activity detected ...
Risk factors for fecal shedding of Salmonella from horses in a veterinary teaching hospital. Identification of risk factors for horses shedding Salmonella in their feces helps identify patients at-risk of infection and protect the overall population through heightened biosecurity. Fecal samples from 230 hospitalized horses were cultured for Salmonella spp. Historical data were collected on 21 putative risk factors and assessed for association with the risk of a horse being culture positive using forwards stepwise logistic regression. Salmonella was isolated from 13 horses--most commonly from either the first (n=5) or second (n=4) sample collected. Only presenting complaint (confounded...
Evidence for a new field Culicoides vector of African horse sickness in South Africa. Between February and May 1998, approximately 100 horses died of African horse sickness (AHS) in the cooler, mountainous, central region of South Africa. On 14 affected farms, 156,875 Culicoides of 27 species were captured. C. imicola Kieffer, hitherto considered the only field vector for AHS virus (AHSV), constituted <1% of the total Culicoides captured, and was not found on 29% of the farms. In contrast, 65% of the Culicoides were C. bolitinos Meiswinkel, and was found on all farms. Five isolations of AHSV were made from C. bolitinos, and none from 18 other species of Culicoides (including C....
Transmission of eastern equine encephalomyelitis virus in central Alabama. A site near Tuskegee, Alabama was examined for vector activity of eastern equine encephalomyelitis (EEE) virus in 2001. More than 23,000 mosquitoes representing 8 genera and 34 species were collected during a 21-week period, and five species, Culiseta melanura, Aedes vexans, Coquillettidia perturbans, Culex erraticus, and Uranotaenia sapphirina, were examined for the presence of virus using a nested reverse transcriptase-polymerase chain reaction for EEE virus. Each species was infected at various times of the mosquito season (May-September) with different minimum infection rates (MIRs). Culis...
A survey of equine abortion, stillbirth and neonatal death in the UK from 1988 to 1997. A detailed review of laboratory records for equine abortion is fundamental in establishing current disease trends and suggesting problems important for further research. Objective: To review the causes of abortion and neonatal death in equine diagnostic submissions to the Animal Health Trust over a 10 year period. Methods: The diagnoses in 1252 equine fetuses and neonatal foals were reviewed and analysed into categories. Results: Problems associated with the umbilical cord, comprising umbilical cord torsion and the long cord/cervical pole ischaemia disorder, were the most common diagnoses (38....
Mosquitoes captured in a horse-baited stable trap in southeast Louisiana. A mosquito study based on collections from horse-baited stable traps was conducted in 1993 and 1994 at 3 sites in geographically and ecologically distinct areas of St. Tammany Parish (southeastern Louisiana) to determine the major horse-feeding mosquito species that could be possible bridging and epidemic vectors of eastern equine encephalomyelitis virus. A total of 4,535 mosquitoes in 1993 and 23,906 in 1994 involving 26 species were collected, of which, depending on the site, Culex salinarius, Cx. (Melanoconion) spp., Aedes vexans, Psophora ferox, Coquillettidia perturbans, Anopheles quadrim...
The prevalence and transmission to exotic equids (Equus quagga antiquorum, Equus przewalskii, Equus africanus) of intestinal nematodes in contaminated pasture in two wild animal parks. Wild equids maintained in large enclosures may suffer from helminth diseases because common hygiene practices have only limited effects on parasite populations. Weekly monitoring of helminth prevalences and pasture infestation was performed for 1 yr in several extensive maintenance systems of two wildlife parks with similar climates to determine when veterinary intervention to control parasites would be useful. We also sought evidence of natural immunogenic reactions among herds of Chapman zebras (Equus quagga antiquorum), Przewalski's horses (Equus przewalskii) and dwarf donkeys (Equus asinus...
Collaborative study for the establishment of a European Pharmacopoeia Biological Reference Preparation for Clostridia antiserum for serological potency testing of veterinary clostridial vaccines. The European Directorate for the Quality of Medicines (EDQM) has organised an international collaborative study, divided in two phases, aimed at producing and establishing a suitable reference serum for serological potency testing of clostridial vaccines for batch consistency demonstration. In phase 1 a series of pools produced from sera provided by each manufacturer and raised against the broadest range of antigens possible were blended to obtain TN titres which were representative of the range normally elicited by the vaccines under test. Detailed statistical analysis of the data was not pos...
The Australian paralysis tick may be the missing link in the transmission of Hendra virus from bats to horses to humans. Hendra virus is a new virus of the family Paramyxoviridae. This virus was first detected in Queensland, Australia, in 1994; although, it seems that the virus has infected fruit-eating bats (flying-foxes) for a very long time. At least 2 humans and 15 horses have been killed by this virus since it first emerged as a virus that may infect mammals other than flying-foxes. Hendra virus is thought to have moved from flying-foxes to horses, and then from horses to people. There is a reasonably strong hypothesis for horse-to-human transmission: transmission of virus via nasal discharge, saliva and/or...
[Rayer’s studies on the contagion of glanders (1837-1843)]. P. Rayer (1795-1867) had never thoroughly published his experimental studies on the contagion of glanders. His recently un-earthed hand written papers allow us to depict his experimental approach and its results. He was not the first who transmitted glanders from a patient to horses or donkeys. But he did it systematically with glander secretions from acute and chronic cases. Whatever was the disease of the donors the transmitted forms were unpredictably either chronic or acute. His conclusion was that the two forms were two symptomatic aspects of a unique disease. Clinically dormant states we...
Relationship of the livestock trade to schistosomiasis transmission in mountainous area. To study the relationship between the livestock trade and schistosomiasis transmission and to provide an evidence for making a strategy of schistosomiasis control in mountainous areas. Methods: A retrospective survey and analysis was conducted to investigate the prevalence of schistosomiasis in both humans and livestock (cattle, horses, mules, donkeys and pigs), and the number and migration of livestock in Weishan County, Yunnan Province in 1980-1991. Results: A positive correlation was found between the infection rate of residents and the numbers of livestock migration (R = 0.9151, P < 0.0...
A comparison of the vector competence of the biting midges, Culicoides (Avaritia) bolitinos and C. (A.) imicola, for the Bryanston serotype of equine encephalosis virus. Equine encephalosis virus (EEV) is widespread and prevalent in southern Africa. In this study, the oral susceptibility of Culicoides (Avaritia) imicola Kieffer (Diptera: Ceratopogonidae) to EEV was confirmed. In addition, C. (A.) bolitinos Meiswinkel, collected in the high-lying eastern Free State, South Africa, was systemically infected with the Bryanston serotype of EEV after feeding through a membrane on artificially infected equine blood containing 4.7 log10 PFU/mL of EEV. The mean infectivity of Bryanston virus in C. bolitinos increased from 1.2 log10 PFU/midge, in midges assayed for viru...
Transmission of Anaplasma phagocytophila (human granulocytic ehrlichiosis agent) in horses using experimentally infected ticks (Ixodes scapularis). Most human granulocytic ehrlichiosis (HGE) studies carried out in horses use needle inoculation of infected leucocytes or cell cultures. This route of inoculation does not accurately reflect natural infection of the tick-borne agent. To investigate whether tick transmission influences the course of granulocytic ehrlichiosis in the horse model, experimental transmission through infected laboratory-reared Ixodes scapularis ticks was attempted into two healthy horses. One additional horse served as negative control and was exposed to uninfected ticks. Eleven days after exposure to nymphal or adul...
Survival of equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus in multidose ophthalmic solutions. To determine survival over time of infectious equine herpesvirus-4, feline herpesvirus-1, and feline calicivirus in three commercially available and commonly used ophthalmic solutions (eyewash, fluorescein, and proparacaine HCl). Methods: Viruses used in this study were originally isolated from eyes of animals referred to the University of Illinois. Equine herpesvirus-4 was propagated in MDBK cells and feline herpesvirus-1 and feline calicivirus in CRFK cells. Methods: After separately inoculating a designated solution with a specific titer of an individual virus, solutions were incubated per ...
Distribution of mecA-harboring staphylococci in healthy mares. The prevalence of staphylococci that harbor the mecA gene responsible for methicillin resistance was examined in healthy breeding mares. Staphylococci often cause diseases of horses such as metritis, keratitis, and abscess. Methicillin-resistant staphylococci would make antibiotic treatments ineffective, so it may be significant to know the distribution of mecA-harboring staphylococci in mares. Isolation of mecA-harboring staphylococci was achieved from nares and pasterns of 100 mares in Hokkaido, Japan. From 13% of the mares, mecA-harboring staphylococci, including 15 isolates of Staphylococc...
Detection of equine Babesia spp. gene fragments in Dermacentor nuttalli Olenev 1929 infesting mongolian horses, and their amplification in egg and larval progenies. Babesia equi (EMA-1) and Babesia caballi (BC48) gene fragments were amplified by polymerase chain reaction (PCR), in blood samples, and partially fed-females and egg and larval progenies of Dermacentor nuttalli, collected from horses in Altanbulag, Tuv Province, Mongolia. While Babesia parasite DNA was detected in some horse blood samples during the first PCR, all positive cases in partially fed-female ticks, eggs and larvae were confirmed by nested PCR. Present study reinforces earlier similar findings in unfed D. nuttalli ticks collected from an open space vegetation in Bayanonjuul, Tuv Prov...
