Evaluation of Non-Invasive Sampling Techniques for the Molecular Surveillance of Equid Herpesviruses in Yearling Horses.

BACKGROUND: Equid alphaherpesvirus 1 (EHV-1) is a highly contagious respiratory tract pathogen of horses, and infection may be followed by myeloencephalopathy or abortion. Surveillance and early detection have focused on PCR assays using less tolerated nasal swabs. Here, we assess non-invasive non-contact sampling techniques as surveillance tools in naturally equid gammaherpesvirus 2-shedding horses as surrogates for EHV-1. METHODS: Horses were individually housed for 10 h periods on 2 consecutive days. Sampling included nasal swabs, nostril wipes, environmental swabs, droplet-catching devices, and air sampling. The latter was completed via two strategies: a combined air sample collected while going from horse to horse and a collective air sample collected at a stationary central point for 6 h. Samples were screened through quantitative PCR and digital PCR. RESULTS: Nine horses on day 1 and 11 horses on day 2 were positive for EHV-1; overall, 90.9% of the nostril wipes, 81.8% of the environmental surfaces, and 90.9% of the droplet-catching devices were found to be positive. Quantitative analysis showed that the mean DNA copies detection per cm2 of nostril wipe sampled concentration (4.3 × 105 per day) was significantly (p < 0.05) comparable to that of nasal swabs (3.6 × 105 per day) followed by environmental swabs (4.3 × 105 per day) and droplet catchers (3.5 × 103 per day), respectively. Overall, 100% of the air samples collected were positive on both qPCR and dPCR. In individual air samples, a mean concentration of 1.0 × 104 copies of DNA were detected in per m3 air sampled per day, while in the collective air samples, the mean concentration was 1.1 × 103. CONCLUSIONS: Environmental samples look promising in replacing direct contact sampling. Environmental and air sampling could become efficient surveillance tools at equestrian events; however, it needs threshold calculations for minimum detection levels.

Taylorella equigenitalis in Icelandic intact males compared with other horse breeds using natural cover.

BACKGROUND: Contagious equine metritis (CEM) is caused by Taylorella equigenitalis. It is a venereal disease that is detected in some breeds more than others and can cause temporary infertility with substantial costs for regular testing, sanitation and retesting. There was a perceived increase in T. equigenitalis-positive cases in Icelandic intact males where natural cover is common. OBJECTIVES: We aimed to investigate the prevalence of T. equigenitalis in Icelandic intact males and compare to draught horse and Haflinger intact males. We hypothesised that prevalence of T. equigenitalis is higher in Icelandic compared with draught and Haflinger intact males. STUDY DESIGN: Cross sectional. METHODS: Swabs from 76 Icelandic, 35 Haflinger, and 51 draught horse intact males were collected on 38 different farms and analysed by qPCR. Animals were further stratified into active breeding and non-breeding animals and age groups (1.5-7.0 and 8.0-26.0 years). Fisher's exact tests and mixed effect logistic regression with 'farm' as random effect were used to estimate differences in odds for T. equigenitalis-positive test results. RESULTS: The overall prevalence of T. equigenitalis in included intact males was 16.7% (27/162). The odds for T. equigenitalis-positive intact males were significantly higher in Icelandic compared with draught and Haflinger intact males (Odds ratio [OR] = 6.42, 95% confidence interval (CI) = 1.43-28.8, p = 0.02). Odds for T. equigenitalis-positive intact males were significantly lower in active breeding compared with non-breeding animals (OR = 0.09, 95% CI = 0.01-0.54, p = 0.009). Age had no significant influence on test results. MAIN LIMITATIONS: Convenience sampling with regional restrictions to Southern Germany and Austria, small sample size. CONCLUSIONS: Significantly higher odds for T. equigenitalis-positive intact males were found within Icelandic over draught and Haflinger and within non-breeding animals compared with active breeding animals. Findings suggest that non-breeding animals could be a reservoir for T. equigenitalis. Testing for CEM should therefore be routinely performed in Icelandic horses prior to breeding and investigations into epidemiology and reservoirs on affected farms should be initiated.

Updated ACVIM consensus statement on equine herpesvirus-1.

Equine herpesvirus-1 (EHV-1) is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). The previous consensus statement was published in 2009 and considered pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment. A recent survey of American College of Veterinary Internal Medicine large animal diplomates identified the need for a revision to this original consensus statement. This updated consensus statement is underpinned by 4 systematic reviews that addressed key questions concerning vaccination, pharmaceutical treatment, pathogenesis, and diagnostic testing. Evidence for successful vaccination against, or effective treatment of EHV-1 infection was limited, and improvements in experimental design and reporting of results are needed in future studies of this important disease. This consensus statement also updates the topics considered previously in 2009.