Isolation and Molecular Characterization of Huma Metapneumovirus from Children with Acute Respiratory Tract Infections at Kenyatta National Hospital, Kenya in 2008

Abstract

Human metapneumovirus (hMPV) is a respiratory viral pathogen that is associated with acute respiratory tract infections (ARTI) in very young children, elderly persons, and immunocompromised patients. Two subtypes of hMPV exist (A and B) which are further divided into subgroups (A1 and A2, and B1 and B2). South Africa is the only African country where hMPV has been isolated and studied Important questions remain on the contribution of hMPV to ARTIs in Kenya .This study aimed at to detect and study the molecular characterization of hMPV from children with ARTI at KNH, in 2008. One hundred and fifty archived nasopharyngeal aspirates from hospitalized children below 5 years with ARTI at Kenyatta National Hospital in 2008 were used. The samples were cultured on LLC-MK2 cells and viral RNA extracted from CPE positive cells. Conventional PCR and sequencing was done for F and G genes. Phylogenetic analysis of the F gene was done by neighbor-joining algorithm using MEGA version (5.02). Of the 150 samples, 7 (4.67%) were PCR positive for both F and G gene proteins. Pylogenetic analysis of the F gene showed that two subtypes; A2b and B2 were in circulation. Subtype A2 accounted for 83.3 % of the isolates. All the Kenyan isolates were closely related to the Chinese isolates suggesting that they had a common origin. The detection of hMPV suggests its involvement in pediatric pneumonia in Kenya The presence of two subtypes (A2 and B2) during the same epidemic period (2008) might suggest that the epidemic was shifting to favor either A2 or B2 strains in the subsequent seasons