Using indirect ELISA and PCR for the diagnosis of equine herpes virus-1 (EHV-1) infection in Egypt

Abstract

The present study was carried out for studying the prevalence of equine herpes virus-1 infection among equines in different Governorates of Egypt. One hundred eighty two equines of different ages, sexes, localities and breeds showing signs of fever, respiratory manifestations, abortions, ataxia, dog sitting position, limb edema, foal depression and death were examined for the isolation of EHV-1 on both embryonated chicken eggs and baby hamster kidney (BHK) cell culture, the aborted fetuses were histologically examined for the detection of inclusion bodies. Serum samples were collected to detect immunoglobulin-G specific to EHV-1 by using ELISA. Nasopharyngeal swabs isolated virus and the aborted fetal tissues were tested by PCR using specific primers to prove the infection with EHV-1. The prevalence of EHV-1 infection in the examined animals was recorded as 4.94%. It was prevalent in Cairo, Giza, Kafr Elsheikh, Monofeia, El Sharkia Governorates. The EHV-1 was isolated on the embryo chicken eggs and the pock lesion was appeared on the chorio-allantoic membranes. The cytopathic effects were also observed in tissue cultures. The Liver of aborted fetuses showed necrosis of all hepatic tissue and activation of Kupffer cells with hemosiderin and the detection of eosinophilic intranuclear inclusion bodies. Indirect ELISA could detect IgG in all infected equines (n=9) from which EHV-1 isolated. PCR proved the infection with EHV-1 in the aborted fetal (n=3) tissues and gave similar results by using the horses nasopharyngeal swabs isolated virus where 489 bp PCR products were detected in both. In conclusion, EHV-1 is prevalent in different Governorates in Egypt. EHV-1 infection could be diagnosed by intranuclear eosinophilic inclusion bodies in the aborted fetal tissues. The indirect ELISA could diagnose EHV-1 infection in all ages and sexes groups. PCR applied on aborted fetal tissues is better for the diagnosis of EHV-1 infection than that based on the horse nasopharyngeal swabs isolated virus due to saving time and money.