Sequence and Phylogenetic analysis of the VP1 segment of chicken infectious anemia virus (CIAV) during an outbreak in Palestine

Abstract

In this study, chicken infectious anemia virus (CIAV) was detected in two unvaccinated commercial broiler flocks,
showing clinical signs relevant to Chicken infectious anemia (CIA) disease. The clinical signs included subcutaneous
hemorrhage, depression and death. Necropsy findings were pale liver, severe atrophy of bursa of the Fabricius and
thymus and discoloration of the bone marrow. DNA was extracted from the livers of the infected birds and the VP1
gene was detected by polymerase chain reaction. The virus strains were detected and genetically characterized in
almost the whole VP 1 gene (1338 base pairs). The nucleic acid analysis showed that the two Palestinian strains had
99.9% similarity and 98.7% similarity to a strain from chickens in Bangladesh (Accession no. AF395114) and 98.5% to a
strain from a human fecal sample (Accession no. JQ690762) from China in the same cluster. The lowest similarity
(94.7%) was with a strain isolated from chickens in China (Accession no. KU645525). Alignment of the deduced VP1
amino acids showed that the two Palestinian strains shared 100% homology (with one silent mutation encoded Leucine
at residue no 97(97L)), classified as high pathogenicity based on glutamine at residue in position 394 (394Q). The highest
similarity was with the Bangladesh 99.8% (AAM20899), Brazil 99.5% (APQ44719) and China (AAZ40209) 99.5% strains,
while the lowest was with the China strain (AFR46599) 96.6%. The study provided valuable information on the
molecular characterization of CIAV strains in Palestine for the first time.