Date of Award

January 2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biology

First Advisor

Jefferson Vaughan

Abstract

Avian malaria is a disease caused by intracellular parasites transmitted by mosquitoes and is detrimental to individual birds and their populations. Although it is sub-lethal in most instances, avian malaria can result in anemia, lower fertility, and reduced migration ability. The Turtle Mountains is a unique ecoregion in North Dakota and provides habitat for various bird and mosquito species that differ from other parts of the state. Previous research has defined the mosquito fauna and occurrence of avian malaria in the Red River Valley region of eastern North Dakota and Northwest Minnesota; however, no research has been conducted in the Turtle Mountains. Mosquito population dynamics are vital to understanding the transmission dynamics of malaria. This research had three objectives. First, the species composition, seasonal abundances, and malaria infection status of host-seeking mosquitoes were determined throughout two summer seasons. Abundances and species compositions of mosquitoes differed from 2019 to 2020, but there were no haemosporidian infections identified. Second, blood from local and migrating birds in the Turtle Mountains was collected to establish the occurrence of avian malaria in the region. This study determined the prevalence of avian haemosporidian parasites in both migratory birds and birds that remain permanent residents throughout the seasons. Avian haemosporidians were present in both local and migratory birds captured in the Turtle Mountains. Based on this research in the Turtle Mountains, it appears that the avian haemosporidian transmission occurs for migratory birds prior to their arrival the Turtle Mountain ecoregion. Third, laboratory studies determined the relative competencies of different mosquito species to support the development of Plasmodium. Despite successful infection of Plasmodium in some Culex pipiens, the parasite was unable to fully develop into sporozoites within the vector. Plasmodium was unable to develop into oocysts in Aedes aegypti or Culex tarsalis. Future studies should focus on climate change and its impact on the mosquito populations of the Turtle Mountains. The introduction of a new competent vector or the increase of a current competent vector would greatly influence the transmission of avian parasites. Increased transmission of current parasites or the introduction of a new parasite species would negatively impact bird populations of the area.

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