Avipoxvirus in Egypt and African continent: A review

Abstract

Fowl pox disease is a slow-spreading viral infection of wild and domesticated birds of both genders, all ages and breeds. The disease occurs in two distinct forms; the more common cutaneous or dry form and the less common diphtheritic form. Fowl poxvirus (FWPV) is a member of the Avipoxvirus (APV) and it is one of the greatest challenges facing the poultry industry, its incidence is higher in tropical and subtropical countries. It causes a significant level of morbidity and increased mortality, especially in the diphtheritic form which may reach to 50%. Avipoxvirus has been recorded in Egypt and Africa in the early of 1960, since then, it has been recorded in variable domesticated and wild bird species in different countries and Governorates. The free-living and wild birds represent a potential threat and source of infection for the domesticated poultry species. In the last ten years, the phylogenetic analysis of the partial genome sequences has gained insight into the evolutionary biology of APV in Africa. One of the main characters of APV is relative genetic stability, especially in fpv167 region of the genome. This area of the genome clustered the APV of chicken and turkey origin phylogenetically into fowl poxvirus subclade A1 together with other avipoxviruses (APVs) isolated from Galliformes worldwide. However, the pigeon poxviruses phylogenetically belong to subclade A2 with other APVs isolated from Columbiformes worldwide. The analysis of the fpv140 region provides a further comprehensive taxonomic classification based on the virus-host origin and distribution, especially in the case of the pigeon poxvirus (PGPV), which clustered separately into different subclades according to their geographical distribution. This review focus on the origin, distribution, classification and taxonomy of APVs circulating in Egypt mainly with a brief report on the situation of APVs in the other neighboring.

Molecular Detection of Reticuloendotheliosis Virus 5′ Long Terminal Repeat Integration in the Genome of Avipoxvirus Field Strains from Different Avian Species in Egypt

“…The molecular detection using PCR is widely accepted as a sensitive, specific, and rapid molecular tool for the detection of APV genomes [46,59]. In this regard, several studies have documented the isolation of APVs from poultry in Egypt [44,48,49]. Our present molecular findings revealed that the APV P4b gene was successfully amplified from all 40 tested isolates, which is in agreement with that obtained in previous studies [21,22].…”

“…In accordance with PGPV, it was considered to be different from FWPV, as they showed host specificity and different profiles with the nucleotide sequence analysis of the P4b gene [24,25,66]. Interestingly, the mans17P isolate identified in the present study showed 100% identity to other PGPVs obtained from GenBank, while the PGPV identified in this study was different from FWPV (mans17F), TKPV (mans17T), and CNPV (mans17C), with 91.7% identity and 44 nucleotide substitutions [4,22,44].…”

“…Taken into account, the acquired retroviral genes expression can alter the host's biological properties and results in a new modified virus emergency and the currently used vaccines, which in turn leads to inadequate protection and sometimes causes recurring infections [38,39,44]. It should be stressed that FWPV strains carrying REV sequences are more pathogenic to poultry [45].…”

“…It should be stressed that FWPV strains carrying REV sequences are more pathogenic to poultry [45]. Although several studies have been conducted on APVs in Egypt [44,[46][47][48][49], little is yet known about the integration of REV in the genome of APV field isolates in our country. To our knowledge, only one study has explored REV as a contaminant of fowlpox vaccines in Egypt [37].…”

Detection and molecular characterization of Avipoxvirus in Culex spp. (Culicidae) captured in domestic areas in Rio de Janeiro, Brazil

“…Avian pox is an important viral disease with a high incidence in tropical and subtropical countries 1 . Caused by a double-stranded DNA virus of the genera Avipoxvirus from the Poxviridae family, which infects and produces clinical signs in numerous domestic and wild birds 2 , 3 .…”