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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.
Vaccine failure caused an outbreak of equine influenza in Croatia. In April 2004 an outbreak of equine influenza occurred at the Zagreb hippodrome, Croatia. Clinical respiratory disease of the same intensity was recorded in vaccinated and non-vaccinated horses. The equine influenza vaccine used in Croatia at the time of the outbreak contained the strains A/equine/Miami/63 (H3N8), A/equine/Fontainebleau/79 (H3N8) and A/equine/Prague/56 (H7N7). At the same time, the usual strains in vaccines used in Europe were, in accordance with the recommendation of the World Organisation for Animal Health (OIE) Expert Surveillance Panel on equine influenza, A/equine/Newmark...
Henipaviruses: a new family of emerging Paramyxoviruses. Paramyxoviruses have been implicated in both animal and human infections. Some viruses, such as Morbilliviruses are responsible for large-scale epidemics. However, there are limited observations of these viruses crossing the host species barrier in nature. In 1994, in Australia a fatal infection in horses and humans was identified to be caused by a new Paramyxovirus, Hendra virus (HeV), and in 1998 in Malaysia, a closely related virus, Nipah virus (NiV) was responsible for fatal infections in pigs and humans. These two viruses were sufficiently different from previously described Paramyxovirus...
Endemic status of Trypanosoma evansi infection in a horse stable of eastern region of India–a field investigation. Diagnosis of Trypanosoma evansi infection in a horse stable of Eastern Region of India on the basis of examination of Giemsa stained blood smears have been done. A high percentage (12.74%) of horses of this stable was found suffering from T evansi infection. This high prevalence of T evansi in horses, in this area could be considered as an alarming situation which has never been explored previously in horses of Eastern Region of India. After a period of 2 months and 18 days of treatment with quinapyramine sulphate and quinapyramine chloride, reinfection with T evansi in treated horses of this ...
Genetic diversity and zoonotic potential of Cryptosporidium parvum causing foal diarrhea. Cryptosporidium isolates from diarrheic foals in New Zealand (n = 9) were identified as C. parvum, subtyped at two polymorphic loci, and compared with human (n = 45) and bovine (n = 8) isolates. Foal C. parvum isolates were genetically diverse, markedly similar to human and bovine isolates, and carried GP60 IIaA18G3R1 alleles, indicating a zoonotic potential.
Equine viral arteritis: current status and prevention. Recently, there has been increased interest in equine viral arteritis (EVA) among veterinarians and horse owners. Outbreaks of the disease were identified initially in New Mexico, USA in 2006, and in the Normandy region of France in the summer of 2007. Both occurrences were associated with AI of cool-shipped semen. Each was linked to respiratory illness, neonatal death, abortion, development of carrier stallions, and cancellation of equestrian events. In light of the increased interest, this paper will present a brief case history, followed by a review addressing common concerns regarding EVA,...
Persistently infected horses are reservoirs for intrastadial tick-borne transmission of the apicomplexan parasite Babesia equi. Tick-borne pathogens may be transmitted intrastadially and transstadially within a single vector generation as well as vertically between generations. Understanding the mode and relative efficiency of this transmission is required for infection control. In this study, we established that adult male Rhipicephalus microplus ticks efficiently acquire the protozoal pathogen Babesia equi during acute and persistent infections and transmit it intrastadially to naïve horses. Although the level of parasitemia during acquisition feeding affected the efficiency of the initial tick infection, infected t...
Peripheral blood mononuclear cells represent a reservoir of bovine papillomavirus DNA in sarcoid-affected equines. Bovine papillomaviruses of types 1 and 2 (BPV-1 and -2) chiefly contribute to equine sarcoid pathogenesis. However, the mode of virus transmission and the presence of latent infections are largely unknown. This study established a PCR protocol allowing detection of <or=10 copies of the BPV-1/-2 genes E5 and L1. Subsequent screening of peripheral blood mononuclear cell (PBMC) DNA derived from horses with and without BPV-1/2-induced skin lesions demonstrated the exclusive presence of E5, but not L1, in PBMCs of BPV-1/2-infected equines. To validate this result, a blind PCR was performed from ...
Transmission dynamics and changing epidemiology of West Nile virus. West Nile virus (WNV) is a flavivirus that is maintained in a bird-mosquito transmission cycle. Humans, horses and other non-avian vertebrates are usually incidental hosts, but evidence is accumulating that this might not always be the case. Historically, WNV has been associated with asymptomatic infections and sporadic disease outbreaks in humans and horses in Africa, Europe, Asia and Australia. However, since 1994, the virus has caused frequent outbreaks of severe neuroinvasive disease in humans and horses in Europe and the Mediterranean Basin. In 1999, WNV underwent a dramatic expansion of ...
Health management of horses under high challenge from trypanosomes: a case study from Serengeti, Tanzania. Horses kept for recreational riding purposes by a wildlife tourism company in a heavily tsetse fly-infested region of north-western Tanzania were systematically monitored to investigate the occurrence, presentation and management of tsetse-transmitted trypanosomosis. During a 23-month period, 18 clinical cases were diagnosed (Trypanosoma brucei or Trypanosoma congolense were identified) and treated and trypanosomes were implicated of involvement in four deaths. Pyrexia consistently aided early detection (17 cases). Ataxia, weight loss and anaemia were seen in chronic cases and conferred a poor...
American cutaneous leishmaniasis in horses from endemic areas in the north-central mesoregion of Paraná state, Brazil. American cutaneous leishmaniasis (ACL) is an endemic disease in the north-west of Paraná state, Brazil, where it occurs in humans and dogs. Few studies have been undertaken on the occurrence of the disease in other domestic animals and horses. In this study we investigated the infection of horses by Leishmania in ACL-endemic rural areas. Direct agglutination test (DAT) and polymerase chain reaction (PCR) were employed. Fifty-five horses from rural areas in the municipalities of Doutor Camargo, Ourizona, São Jorge do Ivaí, Ivatuba and Santa Fé (Agua do O) were analysed. DAT-detected antibod...
Association of soil concentrations of Rhodococcus equi and incidence of pneumonia attributable to Rhodococcus equi in foals on farms in central Kentucky. To determine whether soil concentrations of total or virulent Rhodococcus equi differed among breeding farms with and without foals with pneumonia caused by R equi. Methods: 37 farms in central Kentucky. Procedures-During January, March, and July 2006, the total concentration of R equi and concentration of virulent R equi were determined by use of quantitative bacteriologic culture and a colony immunoblot technique, respectively, in soil specimens obtained from farms. Differences in concentrations and proportion of virulent isolates within and among time points were compared among farms. Resul...
Estimation of the transmission dynamics of Theileria equi and Babesia caballi in horses. For the evaluation of the epidemiology of Theileria equi and Babesia caballi in a herd of 510 horses in SW Mongolia, several mathematical models of the transmission dynamics were constructed. Because the field data contain information on the presence of the parasite (determined by PCR) and the presence of antibodies (determined by IFAT), the models cater for maternal protection with antibodies, susceptible animals, infected animals and animals which have eliminated the parasite and also allow for age-dependent infection in susceptible animals. Maximum likelihood estimation procedures were used...
Hematophagous Diptera collected from a horse and paired carbon dioxide-baited suction trap in southern California: relevance to West Nile virus epizootiology. Hematophagous Diptera landing on a horse were removed by vacuum, and their numbers were related to a paired carbon dioxide-baited suction trap at three locations in southern California where West Nile virus activity was high during the preceding year. Insects collected from the horse included mosquitoes (nine species), biting midges (Culicoides sonorensis Wirth & Jones), and black flies (Simulium bivittatum Malloch). Mosquitoes were predominantly collected from the head, crest, withers, neck, chest, and shoulders of the horse, whereas biting midges and black flies were predominantly collected ...
Equine rhinosporidiosis in United Kingdom. We report 4 cases of equine rhinosporidiosis in the United Kingdom. These cases provide evidence of spread of infectious agents from rhinosporidiosis-endemic areas to nonendemic areas by increased international movement of livestock. Surveillance should continue for this infective agent of potential relevance for numerous species, including humans.
Venezuelan equine encephalitis virus capsid protein inhibits nuclear import in Mammalian but not in mosquito cells. Venezuelan equine encephalitis virus (VEEV) represents a continuous public health threat in the United States. It has the ability to cause fatal disease in humans and in horses and other domestic animals. We recently demonstrated that replicating VEEV interferes with cellular transcription and uses this phenomenon as a means of downregulating a cellular antiviral response. VEEV capsid protein was found to play a critical role in this process, and its approximately 35-amino-acid-long peptide, fused with green fluorescent protein, functioned as efficiently as did the entire capsid. We detected a...
High subclinical West Nile virus incidence among nonvaccinated horses in northern California associated with low vector abundance and infection. Although horse cases frequently are reported during West Nile virus (WNV) outbreaks, few investigations have focused on the epidemiology of this transmission. From April to October 2003 to 2005, mosquito abundance and infection were monitored 3 days per week at an equine research facility at the University of California, Davis. Thirty-two nonvaccinated horses enrolled as controls in a vaccine study were bled monthly, and their serum was tested for evidence of WNV infection by plaque reduction neutralization test (PRNT). In 2004, one positive Culex pipiens pool was associated with a single hors...
Veterinary management of horse transport. Enormous numbers of horses are transported locally, nationally and internationally every year. National legislation and international guidelines set standards for the health and welfare of animals during transport. As a consequence, equine clinicians have major responsibilities in safeguarding the horse industry against the spread of disease and in being aware of the problems inherent in horse transport. The authors explore road, sea and air transport and their effect on horses. Various types of road transport are available and there are various sources of impact on horses. These include loadi...
Brown-headed cowbirds (Molothrus ater) harbor Sarcocystis neurona and act as intermediate hosts. We tested the hypothesis that brown-headed cowbirds (Molothrus ater) harbor Sarcocystis neurona, the agent of equine protozoal myeloencephalitis (EPM), and act as intermediate hosts for this parasite. In summer 1999, wild caught brown-headed cowbirds were collected and necropsied to determine infection rate with Sarcocystis spp. by macroscopic inspection. Seven of 381 (1.8%) birds had grossly visible sarcocysts in leg muscles with none in breast muscles. Histopathology revealed two classes of sarcocysts in leg muscles, thin-walled and thick-walled suggesting two species. Electron microscopy sh...
Virus recovery rates for wild-type and live-attenuated vaccine strains of African horse sickness virus serotype 7 in orally infected South African Culicoides species. Previously reported virus recovery rates from Culicoides (Avaritia) imicola Kieffer and Culicoides (Avaritia) bolitinos Meiswinkel (Diptera, Ceratopogonidae) orally infected with vaccine strain of African horse sickness virus serotype 7 (AHSV-7) were compared with results obtained from concurrently conducted oral infections with five recent AHSV-7 isolates from naturally infected horses from various localities in South Africa. Culicoides were fed sheep bloods spiked with 10(7.6) TCID(50)/mL of a live-attenuated vaccine strain AHSV-7, and with five field isolates in which virus titre in the blo...
Equine travellers to the Olympic Games in Hong Kong 2008: a review of worldwide challenges to equine health, with particular reference to vector-borne diseases. The past 10-20 years have seen exponential growth in the volume of trade in horses and equine germplasm; and the extent of global horse movements has increased significantly in the last 4 years. In preparing for the transport of elite Olympic horses to Hong Kong in 2008, it will be very important to be as fully informed as possible of the disease situation in both the exporting and importing country, import and re-entry requirements, as well as having a vaccination strategy to protect against particular diseases. In this context the review describes the equine vector-borne disease situation in...
The relationship between equine and human West Nile virus disease occurrence. Cases of human and equine West Nile virus (WNV) disease reported in Texas in 2002 were analyzed to assess their temporal relationship. For each human case with a known residential location, the closest equine case (within a 5 km radius) was selected. A total of 80 human-equine case pairs were identified, 51 (64%) of which were located in urban areas. Dates-of-onset of human and equine cases were positively correlated (r(SP)=0.494, P<0.001). Although overall there was no significant (P=0.207) difference between the dates-of-onset of human and equine cases, in urban areas of Texas equine case...
Glanders: off to the races with Burkholderia mallei. Burkholderia mallei, the etiologic agent of the disease known as glanders, is primarily a disease affecting horses and is transmitted to humans by direct contact with infected animals. The use of B. mallei as a biological weapon has been reported and currently, there is no vaccine available for either humans or animals. Despite the history and highly infective nature of B. mallei, as well as its potential use as a bio-weapon, B. mallei research to understand the pathogenesis and the host responses to infection remains limited. Therefore, this minireview will focus on current efforts to elucida...
