The emergence of subclades A1 and A3 avipoxviruses in India

During the years 2010-2018, avipoxvirus (APV) outbreaks were observed in the domestic chickens and pigeons present in the eastern Indian state of Odisha. Based on typical pox lesions, followed by molecular techniques, the overall morbidity was found to be 18%-19.23% and 16.92%-23% in chickens and pigeons, respectively. The cutaneous forms of the disease were observed with varied rates of mortality, being 47.36%-52.77% in chickens and 39.13%-92% in pigeons. PCR amplification targeting the viral P4b core protein-coding gene and the DNA polymerase gene confirmed the presence of APV strains in 10 birds. Subsequent phylogenetic analysis of these two genes confirmed that the circulating strains were members of APV clade A. The subclade analysis revealed the introduction of A1 and A3 subclades in Indian chickens and pigeons, respectively. This study is the first molecular record of APVs circulating in eastern Indian birds (Odisha) and involves the first use of the polymerase gene to reveal the circulating clades of Indian APVs.

Insights into pathological and molecular characterization of avipoxviruses circulating in Egypt

1. Avipoxvirus (APV) infections are one of many threats inflicting economic losses within the poultry industry, particularly in tropical and subtropical countries. A proper and comprehensive study for APVs is needed to increase the knowledge concerning the diversity and evolution of the virus.2. For this purpose, 136 bird flocks of different species and breeding types were examined for APV infection between October 2016 and November 2017. One hundred and thirty samples had visible pocks on the chorioallantoic membrane (CAM) which were designated as fowl pox-like viruses via amplification of 578 bp from the P4b gene and 1800 bp from the fpv140 locus.4. A comprehensive phylogenetic analysis of fpv167 locus (P4b), fpv140 locus (fpv139 and fpv140) and fpv94 (DNA polymerase) revealed that all the analysed strains belong to fowl pox-like viruses (clade A; subclade A1 and A2). Based on the fpv140 locus full nucleotide sequence, three turkey originated strains were seen to be divergent from chicken originated sequences and branched into novel subclade A1.b.5. Trees comparison, within the term of speculation of virus-host specificity, clearly highlighted a high order specific subgrouping among subclades in the case of the fpv140 locus (including fpv139 and fpv140). Hence, the fowl poxvirus, turkey poxvirus and pigeon poxvirus strains clustered into distinct host-specific subclades A1a, A1.b and A2, respectively, which could not be seen in the FWPV-P4b and DNA polymerase phylogeny.

Occurrence and phylogenetic analysis of avipoxvirus isolated from birds around Jammu

Domesticated fowls, pigeons and turkey birds were screened for avipoxvirus infection from different areas in Jammu region. Based on typical pox lesions the overall occurrence in fowl was found to be 18.52%, 17.03% in pigeons and 57.14% in turkeys. Mortality recorded in chicks was 41.96%, 45.36% in squabs, 100% in poults, and 20.00% in adult turkeys. Both cutaneous and diphtheritic forms of the disease was observed of which the latter was particularly prevalent in young birds. One sample of putative fowlpox virus (FWPV) from skin lesions of a fowl, and two samples of putative pigeonpox virus (PGPV) from skin and diphtheritic lesions each were inoculated on chorio-allantoic membrane (CAM) of 10-12 days old chicken embryonated eggs. A confirmatory diagnosis was made by PCR amplification of a highly conserved P4b gene locus detected in tissue samples from skin, diphtheritic membrane and virus inoculated CAM yielding a predicted 578 bp product. Phylogenetic analysis based on the same P4b gene locus revealed FWPV and turkeypox virus (TKPV) to be 99% related and belonging to clade 1, while PGPV was found to belong to clade 2. All three isolates illustrate considerable heterogeneity within the conserved P4b gene locus. The study indicates that the closely related FWPV and TKPV isolates may have the potential of cross infection between fowls and turkeys and therefore cross transmission studies are suggested.

Multiple gene typing and phylogeny of avipoxvirus associated with cutaneous lesions in a stone curlew

Avipoxvirus (APV) infections have been observed in a wide variety of wild, captive and domestic avian hosts, recently including a range of island endemic and endangered species. However, not enough is known about genome diversity and phylogenetic relationships of APVs, as well as their host-range specificity. A wild stone curlew (Burhinus oedicnemus) was recovered in Sardinia (Italy), showing large wart-like lesions and nodules on both legs and toes, which resulted positive to poxvirus by PCR. Histopathological examination of the lesions showed ballooning degeneration and large intracytoplasmic inclusion bodies consistent with APV infection. A multiple gene sequencing approach was applied to highlight the phylogenetic relationships of this virus with a panel of selected APVs at the clade and subclade levels. This novel isolate was characterized by sequencing partial 4b core protein, P35 (locus fpv140) and DNA polymerase genes and phylogenetic analyses assigned it to clade A, (Fowlpox virus, FWPV), subclade A2. Conservation implications of avian pox presence in Sardinian stone curlews and possibly in other island bird species are discussed.