First Record of HAdV-D20 Among Keratoconjunctivitis Patients in Iraq

Human Adenovirus species D (HAdV-D) was common human viral pathogen especially in eye infection, consists of several types of which HAdV-D8, -D19 and -D37 were common in eye infection. This study includes detection of HAdV-D types implicated in conjunctivitis based on L2 (Penton protein) gene similarity.

Conjunctival swabs were collected from Keratoconjunctivitis patients as eye infection related to adenovirus. Viral nucleic acids were extracted and specific primer pairs for HAdV-D L2 gene (encoding for penton base protein) was used to amplify the target gene and only positive samples were sent to sequencing.

The results revealed that only 6 samples give positive results for L2 gene amplification and then sent for sequencing for L2 (penton protein) gene-based typing. The results show that 4 local isolates (S1, S2, S3, S6) were similar to HAdV-D8 and 2 local isolates (S4, S5) were similar to HAdV-D20. Also the results display that the HAdV-37, prominent HAdV-D type of human eye infection, may be variant of HAdV-D20 due to that six variation were seen in S4and S5 local isolates nucleotide sequence in relation to HAdV-D37: T>C at position 14364, A>C at position 14411, T>C at position 14427, C>A at position 14448, G>A at position 14540 and T>C at position 14617, leading to only 2 amino acid change in resulted penton protein: T (Threonine) instead of K (Lysine) at position 204 and N (Asparagine) instead of D (Aspartic acid) at position 247.

The current study concludes the possibility of implication of HAdV-D20 in eye infections especially conjunctivitis.