title: Analysis of the trap gene provides evidence for the role of elevation and vector abundance in the genetic diversity of Plasmodium relictum in Hawaii.
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.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, University of Hawaii at Hilo, Hilo, HI 96720, USA.
authors.forename: Margaret E M
authors.initials: ME
authors.lastname: Farias
authors.forename: Carter T
authors.initials: CT
authors.lastname: Atkinson
authors.forename: Dennis A
authors.initials: DA
authors.lastname: LaPointe
authors.forename: Susan I
authors.initials: SI
authors.lastname: Jarvi
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000469:parasitology*; D015815:Cell Adhesion Molecules / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D006254:Hawaii; D008288:Malaria / Q000469:parasitology / Q000662:veterinary*; D046109:Passeriformes; D010961:Plasmodium / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D020641:Polymorphism, Single Nucleotide; D015800:Protozoan Proteins / Q000235:genetics*
chemical_list: D015815:Cell Adhesion Molecules; D016054:DNA, Protozoan; D015800:Protozoan Proteins