Fig. 1

Yearly distribution of pvama1 _I-II haplotypes in southern Mexico during 19 years. Of 213 DNA sequences, 15 haplotypes were resolved (denominated H1-H15). The proportion of each haplotype in each year is represented by the size of the oval (only those representing ≥ 0.10 are indicated). Some haplotypes were highly frequent in a particular period and existed in samples collected from different years. There were variations in haplotype frequency. It is possible that certain haplotypes alternated with one another. For instance, H1 was present for almost the entire study, having an increased frequency during 2008–2009 and in 2011. This haplotype seemed to alternate with H8, which had a greater proportion in 2007 and in 2010. No samples from 1996 were tested