Molecular Detection and Epidemiology of Equine Herpesvirus 2 and 5 in Working Equids in Central Ethiopia
Background: Equine respiratory illness is a common problem that impacts the performance of the working capacity of equids. In Ethiopia, respiratory disease is the most common presenting complaint at veterinary clinics and a priority concern for equid owners and veterinary practitioners. Although studies had been conducted in EHV-2 and EHV-5 elsewhere in the world, many unknowns remained. Thus, a detailed study is needed to understand more about the epidemiology of the viruses. This study aimed to detect EHV-2 and EHV-5 from working equids in central Ethiopia.
Methods: Nasopharyngeal swabs were collected from 58 horses and donkeys to detect EHV-2 and EHV-5 using PCR. Viral DNA was extracted and PCR amplification was performed using virus-specific primers 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%) diseased equids. EHV-2 was detected in a significantly higher proportion (P = 0.002) in horses (54.5%; n = 18) than donkeys (4%; n = 1). In contrast, a significantly higher (P = 0.004) proportion of EHV-5 was detected in donkeys (56%; n =14) than horses (18.2%; n = 6). EHV-2 was detected in a significantly higher (P = 0.006) proportion in equids displaying signs of respiratory disease (16/33; 48.5%) compared to those without disease (3/25; 12%). EHV-2 positive equids were seven times more likely to display clinical signs of respiratory disease than EHV-2-negative equids (OR = 6.9; 95% CI: 1.72-27.60). For EHV-5, the observed difference was not statistically significant (P = 0.832). A significantly higher (P = 0.041) proportion of EHV-2 was detected in equids living in midland (52.9%; n = 9) compared with highland (24.4%; n = 10). Equids residing in the midland were four times more likely to be exposed to EHV-2 than highland equids (OR = 3.97; 95% CI: 1.05 - 14.89).
Conclusion: EHV-2 and EHV-5 are highly prevalent both in horses and donkeys residing in central Ethiopia. Species-specific susceptibility differences in EHV-2 and EHV-5 infection are observed. The observed causal association between EHV-2-test-positive and the appearance of clinical signs of respiratory disorders should be further investigated.
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Posted 07 Jan, 2021
On 05 Mar, 2021
On 05 Mar, 2021
Invitations sent on 12 Jan, 2021
On 05 Jan, 2021
On 05 Jan, 2021
On 05 Jan, 2021
On 17 Dec, 2020
Molecular Detection and Epidemiology of Equine Herpesvirus 2 and 5 in Working Equids in Central Ethiopia
Posted 07 Jan, 2021
On 05 Mar, 2021
On 05 Mar, 2021
Invitations sent on 12 Jan, 2021
On 05 Jan, 2021
On 05 Jan, 2021
On 05 Jan, 2021
On 17 Dec, 2020
Background: Equine respiratory illness is a common problem that impacts the performance of the working capacity of equids. In Ethiopia, respiratory disease is the most common presenting complaint at veterinary clinics and a priority concern for equid owners and veterinary practitioners. Although studies had been conducted in EHV-2 and EHV-5 elsewhere in the world, many unknowns remained. Thus, a detailed study is needed to understand more about the epidemiology of the viruses. This study aimed to detect EHV-2 and EHV-5 from working equids in central Ethiopia.
Methods: Nasopharyngeal swabs were collected from 58 horses and donkeys to detect EHV-2 and EHV-5 using PCR. Viral DNA was extracted and PCR amplification was performed using virus-specific primers 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%) diseased equids. EHV-2 was detected in a significantly higher proportion (P = 0.002) in horses (54.5%; n = 18) than donkeys (4%; n = 1). In contrast, a significantly higher (P = 0.004) proportion of EHV-5 was detected in donkeys (56%; n =14) than horses (18.2%; n = 6). EHV-2 was detected in a significantly higher (P = 0.006) proportion in equids displaying signs of respiratory disease (16/33; 48.5%) compared to those without disease (3/25; 12%). EHV-2 positive equids were seven times more likely to display clinical signs of respiratory disease than EHV-2-negative equids (OR = 6.9; 95% CI: 1.72-27.60). For EHV-5, the observed difference was not statistically significant (P = 0.832). A significantly higher (P = 0.041) proportion of EHV-2 was detected in equids living in midland (52.9%; n = 9) compared with highland (24.4%; n = 10). Equids residing in the midland were four times more likely to be exposed to EHV-2 than highland equids (OR = 3.97; 95% CI: 1.05 - 14.89).
Conclusion: EHV-2 and EHV-5 are highly prevalent both in horses and donkeys residing in central Ethiopia. Species-specific susceptibility differences in EHV-2 and EHV-5 infection are observed. The observed causal association between EHV-2-test-positive and the appearance of clinical signs of respiratory disorders should be further investigated.
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Figure 3