Maureen Long, DVM, PhD, DACVIM

Maintenance of excellent health and biosecurity standards at the level of the farm is the MOST effective way of maintaining an outbreak-free industry. All disease outbreaks have an index case and all index cases have a point of origin. Because horses are usually maintained at a "home" farm, then the origin of any outbreak should be traced back to the farm level.

Infectious and non-infectious hemolymphatic diseases generally present with the same clinical symptoms due to cardiovascular insult, lack of tissue oxygenation and possible impending cardiovascular collapse.

The main advantage of genomic strategies for testing is that a live organism is not necessarily needed for diagnosis. While the fact that diagnosis based on molecular techniques does not require live organism, DNA and RNA are subject to the same microbiological, biochemical and physical factors as live organism for degradation.

Staphylococcus aureus is an important human pathogen and is a significant cause of hospital acquired (nosocomial) infection of surgical wounds and infections associated with indwelling medical devices. Staphylococcus aureus can colonize the skin and nares of humans which facilitate its transmission, particularly in the healthcare setting.

Salmonella enteriticus, Neorickettsia risticii (Potomac Horse Fever), Clostridium difficile and Clostridium perfringens are most commonly associated with infectious diarrhea in adults. Foals can have a variety of agents including viral causes and bacterial such as Lawsonia intracellularis.

Neurological disease represents 0.3% (affecting between 0.2 and 0.5% of horses depending on age) of all health problems identified by owners in the latest 2005 Equine National Animal Health and Monitoring Study (NAHMS).14 Likely this is much higher given losses in young horses due to non-infectious neurological causes, in all ages of horses from underreporting of encephalitis, and misdiagnoses of these diseases as lameness and trauma.