There is considerable interest in understanding the mechanisms and function of mosquito innate immunity, with recent research in this area identifying important immune genes and metabolic pathways that appear to influence the ability of mosquitoes to transmit malaria. However nearly all such studies have been conducted under highly controlled lab environments, which is not what mosquitoes and Plasmodium parasites experience in the field. Natural malaria transmission occurs across a temperature range of 15-35 0 C, with the potential for considerable variation in conditions across temporal and spatial scales. We wish to test the hypothesis that temperature has significant impacts on mosquito immune function and vector competence, and to explore whether the insights gained under one set of controlled conditions are sufficient to understand variation in mosquito resistance/refractoriness in nature. We argue that mosquito immune function should be affected by environmental temperature because mosquitoes are small-bodied and cold-blooded. In other insect-parasite systems temperature has profound effects on parasite development and overall host resistance. Whether such effects occur with mosquitoes and malaria and if so, whether these effects are due to impacts of temperature on the parasite, on host immunity, or some combination of both, remains unclear. If temperature does affect mosquito immune function, then temperature may be a potent environmental parameter describing variation in mosquito resistance / refractoriness in natural vector populations and might also explain the disparities in immune responses to different Plasmodium parasites (in particular between some rodent malaria parasites and P. falciparum). More fundamentally, if mosquito immune response exhibits thermal sensitivity, the current approach of outlining immunological mechanism under standard lab conditions is insufficient for understanding natural or transgenic vector competence.

Public Health Relevance

Current understanding of mosquito innate immunity derives almost exclusively from studies conducted under standard laboratory conditions. Yet in nature, mosquitoes and parasites interact across a range of environments. We wish to test the hypothesis that environmental temperature significantly shapes mosquito immune function and determine whether notional resistance mechanisms revealed in the lab can explain variation in mosquito resistance to malaria in the field.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI096036-02
Application #
8267001
Study Section
Vector Biology Study Section (VB)
Program Officer
Costero, Adriana
Project Start
2011-06-01
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2014-05-31
Support Year
2
Fiscal Year
2012
Total Cost
$147,400
Indirect Cost
$47,400
Name
Pennsylvania State University
Department
Zoology
Type
Schools of Earth Sciences/Natur
DUNS #
003403953
City
University Park
State
PA
Country
United States
Zip Code
16802
Brock, Patrick M; Murdock, Courtney C; Martin, Lynn B (2014) The history of ecoimmunology and its integration with disease ecology. Integr Comp Biol 54:353-62
Murdock, Courtney C; Blanford, Simon; Hughes, Grant L et al. (2014) Temperature alters Plasmodium blocking by Wolbachia. Sci Rep 4:3932
Murdock, Courtney C; Blanford, Simon; Luckhart, Shirley et al. (2014) Ambient temperature and dietary supplementation interact to shape mosquito vector competence for malaria. J Insect Physiol 67:37-44
Murdock, Courtney C; Moller-Jacobs, Lillian L; Thomas, Matthew B (2013) Complex environmental drivers of immunity and resistance in malaria mosquitoes. Proc Biol Sci 280:20132030
Cator, Lauren J; George, Justin; Blanford, Simon et al. (2013) 'Manipulation' without the parasite: altered feeding behaviour of mosquitoes is not dependent on infection with malaria parasites. Proc Biol Sci 280:20130711