الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The present study was carried out to evaluate the percent of EHVs infection that menace among working equid populations in Egypt during the period of investigation (13 months) from different localities in four Egyptian provinces including: El-Menia, Assiut, Sohage and Luxor. A total number of 115 working equids (92 horses and 23 donkeys) were clinically examined and sampled from November 2018 till November 2019 for study. These equids sampled in different months of the year, with different ages, and different in sex for epidemiological studies. Two samples were collected from each animal (nasal swab and blood sample) and were subjected to multiplex-PCR for detection of different EHVs infection among equids.
Out of 115 examined equids, 82 cases showed clinical abnormalities and 89.02% of them were PCR-positive for at least one EHVs strain when both samples were considered. Similarly, the remained 33 cases appeared to be apparently healthy and 57.57% of them were PCR-positive for at least one EHV infections when both samples were considered. The clinical signs of the examined equids infected by EHVs and PCR- positive in the current study can be summarized as follow, a higher percentage of EHV infections were detected among equids with acute onset of signs (59.78%), pyrexia (57.61%) and/or systemic illness (45.65%), ocular signs (35.87%) with or without respiratory signs (56.52%). Moreover, EHV-1 PCR-positive horses and donkeys appeared with neurological signs (4.35%) and abortion (1.09%). Also, EHV-5 PCR-positive foal appeared to have large discrete nodules of fibrosis in lungs when grossly postmortem examination was done which may be indicated as equine multinodular pulmonary fibrosis.
In the current study, overall prevalence of EHVs infection among working equids in Egypt was 80.00% (84.78% horses and 60.87% donkeys). The remained cases (n=23, 20.00%) were EHVs free. The most prevalent virus among equids was EHV-2 (61.74%), followed by EHV-5 (43.48%), EHV-1 (20.00%) and EHV-4 (13.04%). Moreover, a higher prevalence of EHV-1 (26.09%) and EHV-4 (17.39%) infections were recorded in donkeys compared to EHV-1 (18.48%) and EHV-4 (11.96%) prevalence in horses. On the other hand, a higher prevalence of EHV-2 (71.74%) and EHV-5 (47.83%) were recorded in horses when compared to an EHV-2 (21.74%) and EHV-5 (26.09%) prevalence in donkeys. Finally, the incidence of gammaherpesviruses (EHV-2 and EHV-5) infection were much higher than that of alphaherpesviruses (EHV-1 and EHV-4).
Regarding to equids health status in this study, of 82 of clinically suspected cases, EHV‐1, -4, -2 and ‐5 infections were observed in 23.17%, 18.29%, 73.17%, and 47.56%, respectively. Also, of 33 apparently healthy equids, EHV‐1, -2 and ‐5 was observed in 12.12%, 33.33%, and 33.33%. EHV‐4 was not detected among apparently healthy horses. Besides, apparently healthy working donkeys were not harbored any of EHVs infection.
Regarding to samples type collected from examined equids, 73.04% and 69.56% of them were PCR-positive in at least one of four EHVs in nasal swabs and blood samples, respectively, of which 78.26% were detected in both samples. The highest prevalence of EHV-4 (10.43%), EHV-2 (51.30%) and EHV-5 (33.04%) was recorded in nasal swab samples compared EHV-4 (8.69%), EHV-2 (46.09%) and EHV-5 (26.09%) prevalence in blood samples, while EHV-1 prevalence was 14.78% either in nasal swabs or blood samples. Unique detection of EHV infections was observed either from 40.87% in nasal swabs or 48.69% in blood samples. Co-infections of alpha and gamma EHV strains were recorded either in clinically suspected or apparently healthy equids. Double detection of EHV infections were observed in 27.83% in nasal swabs and 15.65% in blood samples of examined equids. Besides, triple detection of EHV infections were observed 4.35% in nasal swabs and 5.22% in blood samples of examined equids.
Concerning to different epidemiological data in the current study, a higher prevalence of EHV-1 and EHV-5 was recorded at an age 1 - 5 years compared to the other age groups. While a higher prevalence of EHV-2 and EHV-4 was recorded at an age less than one year compared to the other age groups. Also, the highest prevalence of EHV-1 and EHV-4 was recorded in autumn. While the highest prevalence of EHV-2 was recorded in spring and the highest prevalence of EHV-5 was recorded in winter. Moreover, the highest prevalence of EHV-1 and EHV-2 was detected in males, while the highest prevalence of EHV-4 and EHV-5 was detected in females.
The results in the current study obviously signalize that EHVs are pervasive among equid populations in Egypt so that there is an instant necessity for introduction of active regular surveillance measures to investigate the presence of different EHVs, and other equine viral pathogens in various equid populations around Egypt and to establish a standardized cataloging of equine health status.