Session:

Virology and Viral Infections (Non-HIV)

Abstract No.:

40.079

Title:

Genotyping human metapneumovirus in a Bangladeshi urban pediatric population

Author(s):

M. Rahman¹, M. Alam¹, D. Goswami¹, D. D. Erdman², S. P. Luby¹, W. A. Brooks¹; ¹International Centre for Diarrheal Disease Research, Bangladesh, Centre for Communicable Diseases (CCD), Dhaka/BD, ²Centers for Disease Control and Prevention, Division of Viral Diseases, Atlanta, GA/US

Abstract:

Background: Human metapneumovirus (HMPV) was discovered in 2001 and has rapidly emerged as an important respiratory pathogen. Serological studies indicate that most children are infected with HMPV by 5 years of age. Despite the near universal HMPV exposure in childhood, new infection can occur throughout life due to incomplete protective immunity and exposure to new genotypes. Two major subtypes, A and B, which are further divided into subgroups A1, A2a, A2b, B1 and B2, have been reported. There are limited data on HMPV prevalence and no information about the circulating HMPV strains in Bangladesh.
Methods: Nasopharyngeal wash (NPW) from children <5 years were obtained from a community based febrile surveillance project in an urban population in Kamalapur, Dhaka during April 2004-Dec 2007. HMPV was detected by real-time RT-PCR. We performed genotyping of a subset of HMPV positive specimens by partial sequencing of the F gene and sequence comparison with available genetic data in GenBank. Phylogenetic analysis was conducted using the neighbor joining method.
Results: From April 2004 to December 2007, of 2362 NPW specimens collected from patients presenting with influenza-like illness (ILI), 249 (11%) tested positive for HMPV. HMPV was detected in 16.9%, 1.3 % and 17.4% in 2005, 2006 and 2007 respectively. The F genes of 37 HMPV were successfully typed, revealing that HMPV genotypes A2b (49%), B1 (41%), and B2 (10%) were circulating among the study population. In 2005, 75% of HMPV isolates were genotype A2b, but a switch to predominantly genotype B1 (64%) occurred in 2007. Phylogenetic analysis revealed that most of the HMPV Bangladeshi strains shared close genetic relationship with contemporaneously circulating strains in China, Japan, Taiwan and United Kingdom.
Conclusion: HMPV constituted a considerable proportion of ILI in our pediatric population. The clinical significance of the co-circulation of multiple genotypes of HMPV remains to be investigated.