Molecular detection and assessment of the epidemiological risk factors associated with equine herpesvirus 2 and 5 in working equids in central Ethiopia.

Background: Respiratory disease is the most common presenting complaint at veterinary clinics and a priority concern for equid owners and veterinary practitioners in Ethiopia.

Objectives: This study aimed to report the molecular detection of EHV-2 and EHV-5 and to assess the risk factors associated with infection in working equids in central Ethiopia.

Methods: Nasopharyngeal swabs were collected from 58 horses and donkeys to detect EHV-2 and EHV-5 using PCR targeting the conserved region of glycoprotein B (gB) genes.

Results: From 58 equids, EHV-5 and EHV-2 were detected in 20 (34.5%) and 19 (32.8%) equids, respectively. Concurrent infection with EHV-2 and EHV-5 was found in 6 (10.3%) equids who exhibited respiratory clinical signs. EHV-2 was detected in a significantly higher (p = 0.002) proportion of horses (54.5%; n = 18) than donkeys (4%; n = 1). In contrast, EHV-5 was detected in a significantly higher (p = 0.004) proportion of donkeys (56%; n = 14) compared to horses (18.2% n = 6). EHV-2-positive equids were seven times more likely to display clinical signs of respiratory disease than EHV-2-negative equids (Odds ratio (OR) = 6.9; 95%CI: 1.72-27.60). However, statistically significant (p = 0.832) difference was not observed for EHV-5. EHV-2 was detected in a significantly higher (p = 0.004) proportion of female (50%; n = 16) compared to male equids (11.5%; n = 3).

Conclusions: This study revealed the molecular detection of EHV-2 and EHV-5 in horses and donkeys residing in central Ethiopia. The association between EHV-2-test-positive equids and displaying of clinical signs of respiratory disease was observed, which suggests EHV-2 involvement in the development of respiratory disease; however, it deserves further investigation.