Human metapneumovirus (HMPV) – identified in the year 2001 in Netherlands [1] – is considered one of the important agents causing acute respiratory infection (ARI), especially in infants and young children [2]. However, limited information about HMPV is available in India. The aim of the present report was to provide the preliminary information on HMPV in a North-Eastern region of India.

Clinical specimens of nasopharyngeal/nasal and throat swabs were collected during 2009-12 with prior informed consent from outpatient attendees with clinical features suggestive of respiratory illness at three primary health centers (PHCs) in rural areas of Dibrugarh District of Assam. The samples were transported in viral transport media (Himedia, Mumbai, India) to the laboratory in vaccine carrier box maintaining cold chain. In the laboratory, viral RNA was extracted from 140µL of clinical specimens using commercially available Qiamp Viral RNA mini kit (Qiagen, Hilden Germany) followed by detection using one step RT-PCR kit (Qiagen, Hilden Germany), utilizing primers and methodology as described by Huck [3]. For confirmation and genetic analysis, a few viral isolates were subjected to partial nucleotide sequencing targeting F and N gene of HMPV. The study was approved by the Human Ethics Committee of Regional Medical Research Center, Dibrugarh.

A total of 1548 patients with Influenza-like illness (ILI) were recruited from three PHCs. Out of which, 493 were children aged 5 years or less. More than 50% of such patients (276/493) were included in the present study where HMPV was detected in about 7.2% (20/276). There were equal numbers of males and females (10 each) with mean (SD) age 2.2 (1.5) years. The most common clinical presentations were fever (100%), nasal discharge (100 %), cough (90%) and concomitant history of ILI in the family (50%). Highest prevalence of HMPV was detected in the month of January (46.7%) followed by December (16.7%). Genotyping data available for 3 out of 20 cases (15%) revealed the presence of both A (Subtype A2b) and B (Subtype B2) genotypes (KJ635573-75). The results were in congruence with N gene sequences (KJ635576-77). Genotype-specific amino acids as reported by Yang, et al. [4] were also observed in the sequences obtained in the present study.

In India, HMPV as a cause of ARI is underestimated due to limited data. Existing studies from India show variable prevalence of HMPV ranging from 1%-19% in different settings [5-10]. The prevalence of HMPV in Dibrugarh district of Assam was higher than reported earlier from Eastern India [8]. However, it was lower than reports from Pune and Delhi [5,6]. The circulation of both the detected genotypes of HMPV has previously been reported in India.

Community-based studies regarding the contribution of circulating viruses are scarce in India, where a substantial number of children die each year due to ARI. Evaluating the role of individual etiological agents is of prime importance for the development of effective therapy, and vaccine regimen.

Acknowledgement: The authors thank Mrs Moitreye Lahan for providing technical support in the study.

Contributors: DB, BB and JM conceptualized the study, KY performed RT-PCR, sequence analysis and drafted the manuscript; BB and JM were involved in the critical review of the manuscript.

Funding: Intramural fund of RMRC Dibrugarh; Competing interests: None stated.

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