First Report of Isolation and Molecular Characterization of Felid Herpesvirus-1 from Symptomatic Domestic Cats in Egypt

Abstract

Feline herpesvirus 1 (FHV-1) is one of the main causes of upper respiratory tract infection in cats. Despite its veterinary importance, no previous studies investigated the occurrence of this virus in Egypt. In the present work, a total number of one hundred forty (N = 140) conjunctival and/or oropharyngeal swabs were collected from symptomatic cats during veterinary clinic visits located in two Egyptian provinces. Virus isolation was performed in the Chorioallantoic membranes (CAMs) of 12-days-old SPF eggs. Interestingly, the embryos showed stunting growth and abnormal feathering and infected CAMs showed edematous thickening and cloudiness with characteristic white opaque pock lesions. Polymerase chain reaction (PCR) amplification of the thymidine kinase gene (TK) was successful in 16/140 (11.4%) of the suspected cases. Two of the amplified genes were sequenced and the TK gene sequences of the FHV-1 isolates were highly similar to other reference strains in the GenBank database. Given the above information, the present study represents the first report of feline herpesvirus type 1 (FHV-1) in domestic cats in Egypt. Further studies on the causes of upper respiratory tract infections in cats as well as vaccine efficacy are needed.

Epidemiological Investigation of Feline Upper Respiratory Tract Infection Encourages a Geographically Specific FCV Vaccine

“…The third factor that might account for such a large range is the testing protocol, which can differ based on the presence or absence of an infection, i.e., the population being tested, the kind of specimen, and the technique of testing [ 30 ]. The low prevalence of FHV-1 may also be attributable to the chronicity of the disease in cats [ 31 , 32 ]; it was found to be 15.5% with fewer symptoms than FCV.…”

“…All these clinical signs are similar, as observed in a previous study [ 9 ]. Moreover, it has been revealed that the frequent high fever and corneal ulcers in FHV-1, and FCV refer to throat, tongue, and palate ulcers [ 32 ]. Clinically, URTD is linked with various symptoms, but none can be singled out as the pathognomic indicator of a specific infection.…”

Identification, Genetic Characterization, and Pathogenicity of Three Feline Herpesvirus Type 1 Isolates from Domestic Cats in China

“…We conducted phylogenetic analyses of FHV utilizing various genes, including gB, gD, gE, TK, or whole genome sequences [8,25]. Previous reports have indicated a close relationship among FHV-1 strains and a low relationship with CHV-1 isolates.…”

“…The clinical manifestation of FHV-1 infection can vary from mild, self-limiting cases to severe, life-threatening conditions, contingent upon factors such as the virulence of the viral strain, the immune status of the host, age, and environmental conditions [7]. Common clinical presentations include sneezing, fever, nasal and ocular discharge, conjunctivitis, keratitis, lethargy, anorexia, and coughing [8]. FHV-1 exhibits the capability to establish latency within the trigeminal ganglia [9], with periodic reactivation leading to recurrent episodes of clinical disease, particularly in instances of stress or immunosuppression.…”