Abstract: West Nile Virus (WNV), a member of the family Flaviviridae, was first isolated in 1937. Since the original isolation of the WNV outbreaks have occurred with increase in frequency of cases in humans and horses, apparent increase in severe human disease and high avian death rates. In 1999, 2000 and 2002 outbreaks of the WNV encephalitis were reported in horses, birds and humans from New York and Canada. Ornithophilic mosquitoes are the principal vectors of the WNV and birds of several species chiefly migrants appear to be the major introductory or amplifying host. The pattern of outbreaks in the old and new world suggests that viremic migratory birds may also contribute to movement of the virus. If so, Central America, Caribbean Islands and countries of South America including Venezuela, are in potential risk for suffering a severe outbreak for WNV, since several species of birds have populations that pass trough New York and cross the western north Atlantic or Caribbean Sea. It is important the knowledge of the ecology of WNV as well of the efficacy of control efforts in order to minimize the public health impact in these countries, where all population is susceptible to this infection.

Abstract: OBJECTIVE: To characterise and provide nationally representative estimates of persons with non-fatal horse related injuries treated in American emergency departments. METHODS: The National Electronic Injury Surveillance System All Injury Program (NEISS-AIP) is a stratified probability sample comprising 66 hospitals. Data on injuries treated in these emergency departments are collected and reported. NEISS-AIP data on all types (horseback riding and otherwise) of non-fatal horse related injuries from 2001 to 2003 were analysed. RESULTS: An estimated 102,904 persons with non-fatal horse related injuries (35.7 per 100,000 population) were treated in American emergency departments each year from 2001 to 2003 inclusive. Non-fatal injury rates were higher for females (41.5 per 100,000) than for males (29.8 per 100,000). Most patients were injured while mounted on a horse (66.1%), commonly from falling or being thrown by the horse; while not mounted, injuries most often resulted from being kicked by the horse. The body parts most often injured were the head/neck region (23.2%), lower extremity (22.2%), and upper extremity (21.5%). The most common principal diagnoses were contusions/abrasions (31.4%) and fractures (25.2%). For each year that was studied, an estimated 11 502 people sustained traumatic brain injuries from horse related incidents. Overall, more than 11% of those injured were admitted to hospital. CONCLUSIONS: Horse related injuries are a public health concern not just for riders but for anyone in close contact with horses. Prevention programmes should target horseback riders and horse caregivers to promote helmet use and educate participants about horse behaviour, proper handling of horses, and safe riding practices.

Abstract: Factors associated with the prevalence of osseous fragments (OF) in fetlock and hock joints were investigated in a population of young Hanoverian Warmblood horses selected for sale at auction from 1991 to 1998. The study was based on results of a standardized radiological examination of 3127 horses. The prevalences of OF in the two joints were significantly dependent on the date, type and quality of the auction, the region of origin and on the anticipated suitability of the horses for dressage and/or show-jumping. The probability of finding OF increased with wither-height. Furthermore, there was a significant association of the individual sire with the prevalence of OF in both fetlock and hock joints, and of the maternal grandsire with the prevalence of OF in the hock joints. Consequently, both non-genetic and genetic parameters should be taken into account in order to reduce the prevalence of OF in young Warmblood riding horses.

Abstract: African Horsesickness (AHS) is a controlled disease in South Africa. The country is divided into an infected area and a control area. An outbreak of AHS in the control area can result in a ban of exports for at least 2 years. A retrospective epidemiological study was carried out on data collected during the 2004 AHS outbreak in the surveillance zone of the AHS control area in the Western Cape Province. The objective of this study was to describe the 2004 outbreak and compare it with the 1999 AHS outbreak in the same area. As part of the investigation, a questionnaire survey was conducted in the 30 km radius surrounding the index case. Spatial, temporal and population patterns for the outbreak are described. The investigation found that the outbreak occurred before any significant rainfall and that the main AHS vector (Culicoides imicola) was present in abundance during the outbreak. Furthermore, 63% of cases occurred at temperatures < or = 15 degrees C, the Eerste River Valley was a high risk area, only 17% of owners used vector protection as a control measure and 70% of horses in the outbreak area were protected by means of vaccination at the start of the outbreak. The study revealed that the current AHS control measures do not function optimally because of the high percentage of vaccinated horses in the surveillance zone, which results in insufficient sentinel animals and the consequent failure of the early warning system. Alternative options for control that allow continued export are discussed in the paper.