Analysis of the trap gene provides evidence for the role of elevation and vector abundance in the genetic diversity of Plasmodium relictum in Hawaii

• Published in: Malaria Journal
• Main Authors: Farias Margaret E M, Atkinson Carter T, LaPointe Dennis A, Jarvi Susan I
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2012
• Subjects: Plasmodium relictum; trap; SNP; Amakihi; Diversity; Hawaiian honeycreepers; Mosquitoes; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/1475-2875-11-305; https://doaj.org/article/d0802fcc6b7c43659bd3327b35362df6

Abstract Background The avian disease system in Hawaii offers an ideal opportunity to investigate host-pathogen interactions in a natural setting. Previous studies have recognized only a single mitochondrial lineage of avian malaria ( Plasmodium relictum ) in the Hawaiian Islands, but cloning and sequencing of nuclear genes suggest a higher degree of genetic diversity. Methods In order to evaluate genetic diversity of P. relictum at the population level and further understand host-parasite interactions, a modified single-base extension (SBE) method was used to explore spatial and temporal distribution patterns of single nucleotide polymorphisms (SNPs) in the thrombospondin-related anonymous protein ( trap ) gene of P. relictum infections from 121 hatch-year amakihi ( Hemignathus virens ) on the east side of Hawaii Island. Results Rare alleles and mixed infections were documented at three of eight SNP loci; this is the first documentation of genetically diverse infections of P. relictum at the population level in Hawaii. Logistic regression revealed that the likelihood of infection with a rare allele increased at low-elevation, but decreased as mosquito capture rates increased. The inverse relationship between vector capture rates and probability of infection with a rare allele is unexpected given current theories of epidemiology developed in human malarias. Conclusions The results of this study suggest that pathogen diversity in Hawaii may be driven by a complex interaction of factors including transmission rates, host immune pressures, and parasite-parasite competition.