SAEVA Proceedings 2014 | Page 125

46TH  ANNUAL  CONGRESS  OF  THE  SAEVA        SKUKUZA      16-­‐20  FEBRUARY  2014   125     antibody concentrations due to vaccination or previous exposure was strongly protective and a higher qPCR detection rate for EHV-1 and -4 was reported during winter months. These have been postulated to be associated with management practices e.g. a higher density of young animals kept indoors for training and sales purposes. Arguably, one of the most important risk factors associated with respiratory infections, is physiological stress. Stress has been associated with recrudescence and shedding of latent EHV-1 and -4 infections and additionally the immunosuppressive influence of stress on the body increases the susceptibility of naive animals to new respiratory infections. Transport, confinement, handling and management at a sales complex may contribute greatly to the physiological stress experienced by young animals. Information about the prevalence of important equine respiratory pathogens and nasal shedding and any association with health, vaccination status or management factors, will increase understanding of the risks to horses attending sales events in South Africa and enhance the ability to design risk mitigation and management strategies. Prospective cohort studies in Thoroughbred horses < 2 years-old consigned to bloodstock sale aimed to determine: • Prevalence of EHV-1 and -4 shedding by serial nasal swab collection for qPCR testing in suspect cases of infection; and • Facility of early detection of possible respiratory infections by monitoring horses for elevated rectal temperature and nasal discharge; Materials and methods Data was collected at two separate Thoroughbred Breeders Association (TBA) National Two Year-Old Sales during August of 2011 and 2013 at the Gosforth Park Sales Complex in Germiston, Gauteng Province. The horses’ stay following arrival at the Complex consisted of an approximately weeklong pre-sales preparation followed by the actual sales occurring over the final 2 days before departure. The study populations’ were colts and fillies selected from the TBA’s Sales Catalogue and based on stud farm owners’ willingness to participate in the study and previous experience regarding the availability of accurate records from these farms. In 2011, preliminary data was obtained from 35 animals originating from one farm in the Eastern Cape (n=19 horses) and one in KwaZulu-Natal (n=16 horses) Provinces, respectively. In 2013, a more extensive study observed 93 animals from 8 farms situated in the Western Cape (n=3 farms; 31 horses), Eastern Cape (n=2 farms; 18 horses) and KwaZulu-Natal (n=3 farms; 44 horses) Provinces, respectively. Upon arrival at the sales complex, nasal swabs for molecular detection of viral nucleic acid using a duplex quantitative-polymerase chain reaction (qPCR) for EHV-1 and EHV-4 were collected. Duplicate 15 cm metal shaft rayon-tipped swabs were advanced simultaneously into the ventral meatus of either the horse’s left or the right nostril and gently rotated against the mucous membranes. Following this, each swab was placed in a sterile, dry, 15 ml conical tube, refrigerated at 4–6 °C and transported on ice to Faculty of Veterinary Science, University of Pretoria and a qPCR analysis was performed according to the method of Diallo et al, (2007). Thereafter, twice-daily monitoring for clinical evidence of pyrexia and nasal discharge   125