Figure 4.

Alternate possibilities for distribution of genetic variation in parasites within a hypothetical country. (A) Haplotype frequencies (each unique sequence has a different color) from three locations within one country where nematodes were collected, and from a second country (haplotypes in grey), indicate all three locations are genetically distinct. The resulting haplotype network indicates sequence divergence between haplotypes. Taken together, these results would support the conclusion that there are three transmission zones in which parasites persist. (B) Haplotype frequencies in three locations where nematodes were collected indicate that they are genetically similar. The resulting haplotype network supports the conclusion that there is one transmission zone, and that recrudescence is local. (C) Haplotype frequencies in three locations indicate that they are genetically similar. The haplotype network indicates that recrudescence may have come from a migrant source, because haplotypes are shared between countries (1 and 2).