Figure 2.

MDV haplotypes present on Pennsylvanian poultry farms between October 2012 and September 2015. Individual farms are identified as A–M and the presence of multiple poultry houses on these farms as H1, H2, etc. Individual colored bars represent different haplotypes as described in Fig. 1. Split color bars for an individual month indicate the presence of multiple haplotypes present at that time within a single dust sample. The pale green bar with a ‘–’ indicates the presence of two forms of the Rispens haplotype: one with its characteristic meq gene that contains an insert not typically present in wild-type virus and a second form that has lost this insert (see main text). ‘c’ denotes a sample that had M5 cloned. The company (W–Z) affiliated with each farm is indicated by dotted, white, gray, or black-filled circles, respectively. The asterisks indicate the points where farm A and farm C switched company affiliation.