Figure 4. Human metapneumovirus (HMPV) transmission network among the adults and children in Kuala Lumpur between February 2012 and May 2014.

The transmission network was inferred from the newly-sequenced F (n = 85) and G (n = 82) genes based on the Tamura-Nei 93 (TN93) pairwise distance estimates⁵¹ performed using a custom script in Python (release 3.2.6) with 1,000 bootstrap replicates. (A) The monthly distribution of transmission clusters inferred for F and G genes at the genetic distance cutoffs of 0.2% and 1.2%, respectively. The three common transmission clusters identified in both genes were highlighted in circles (dotted lines). Probable direction of disease transmission within a cluster was estimated by placing a directed edge from the putative “donor” node to the “recipient” node(s), where the estimated date of infection, EDI_donor is older than the EDI_recipient¹⁸. (B) The monthly frequency (in absolute numbers of samples/individuals) of HMPV sub-lineages co-circulating in the study population. HMPV sub-lineages A2b, B1, B2, and the novel sub-lineage of A2 were indicated by their respective colours.