Molecular size variation and RFLP patterns of the csp gene of Plasmodium vivax isolates from the central Pacific Ocean coast region of the Americas A and B, PCR amplified product size. A) Mexican samples; ~700 pb -vk210a (lane 1) and ~700 pb -vk210b (lane 2) had the same molecular size. Lane 3 and 4, show mixed genotype infections: (vk210b and ~500 pb- vk210c) and (>700 pb-vk247 and vk210c), respectively. B) Nicaraguan and Mexican samples; fragments of ~700 bp (lanes 4, 5 and 8; Nir1), ~650 bp (lanes 1, 3 and 9; Nichn), ~600 bp (lanes 2 and 7) and vk210a from Mexico (lane 6) are shown.RFLP patterns: C) Mexican samples; vk210d (lane 1–2), vk210b ( Lane 3–4), vk210c +vk247 (lane 5–6), and vk247+vk210a (lane 7–8). D) Mexican and Peruvian samples; vk210a (lanes 1–4, two samples), vk247 (lanes 5–8, two samples: Mexican and Peruvian); and mixed infection Vk210a-vk247 (lane 9–10). E) Nicaraguan samples; vk210a like - Nir1 isolate (lane 1 and 2), vk210e - Nichn isolate (lane 3–4), vk210f - Nir2 isolate (lane 5 and 6) are shown. C, D and E: odd numbers indicate Alu1 digestion and round numbers indicate BstI digestion. 1% agarose gels and ethidium bromide for staining were used. M, marker 1 kb.