RNA extraction and reverse transcription-polymerase chain reaction (RT-PCR) were performed as previously described (4) . Primers used for the amplification of the RSV L gene were as follows: forward primer 5′-GGTA-GAATCTACATATCCTTACCTAAGTG-3′ (genome location 14881-14909, [reference strain RSV A Melbourne, Australia/2/'61] GenBank accession no. M74568), reverse primer 5′-CGAGATATTAGTTTTTGACAC-3′ (genome location 15190-15210, GenBank accession no. M74568). The HMPV forward primer, 5′-GCGCGTTCTGAG-GACAGGTTGG-3′ (HMPV genome location 3163-3180, GenBank accession no. AF371367, G/C clamps are underlined) and reverse primer, 5′-GCGCTCAAGCCGGATG-GTTTTGG-3′ (3425-3444, GenBank accession no. AF371367, G/C clamps are underlined) used for the amplification of the HMPV F gene were based on regions of the F gene conserved in New Haven, Netherlands, and Australian strains (4). PCR reactions were performed by using HotStar (Qiagen, Inc., Valencia, CA) and amplification cycles were as follows: 95°C for 15 min followed by 35 cycles of 94°C for 1 min, 55°C for 1 min, and 72°C for 1 min, and a final 10-min cycle at 72°C. Each set of reactions contained appropriate negative (water) and positive control samples for the RT (HMPV-positive nasal wash) and the PCR (HMPV cDNA) steps.