Taking a Bite Out of Mosquito Research

November 27, 2012

Newcomer to the Department of Environmental Science and Technology and a native of New Zealand or Kiwi, Dr. Paul Leisnham brings his latest research on mosquitoes and human health from ‘down under’ to Maryland. Human-induced environmental changes, such as land use modification and climate change, have been linked to the reemergence of major diseases carried by mosquitoes. These offer classic examples of how disrupted ecosystems adversely affect human health.

Why Mosquitoes?

“I became interested in mosquitoes because... they bite me!” says Dr. Leisnham, an assistant professor, whose research is centered on the ecology of native and invasive mosquitoes in water-filled containers, wetlands, and drainage systems. “Aside from being a nuisance and health threat, mosquitoes became a fascination to me when I better understood their lifecycle. ”The mosquito lifecycle is complex with different life stages: eggs, aquatic larvae, and flying adults. Each of these stages has very different interactions with their environment, explains Dr. Leisnham, and by studying these interactions we can better understand how they affect human health. From over 2500 different species of mosquitoes throughout the world of which 150 occur in the United States, Dr. Leisnham’s favorite is the Aedes tormentor. Aedes is originally found in tropical and subtropical zones, but has spread by human activity everywhere excluding Antarctica. The name comes from the Greek meaning "unpleasant" or "odious", so called because of the diseases this type of mosquito transmits, including dengue fever and yellow fever.

Mosquitoes and Human Health

It’s not a secret that mosquitoes transmit some of the most serious diseases worldwide. Some of these including malaria, dengue, and West Nile virus, which cause millions of deaths, drive cycles of poverty, and contribute to dramatic socio-economic disruption. Additionally, many diseases that are transmitted by mosquitoes are becoming more intense and spreading due to environmental changes, including climate change, urbanization, and the invasion of exotic pests. “Diseases that are spread by mosquitoes are among human's deadliest foes and have changed human history,” says Dr. Leisnham. He has explored these ecological, social, and economic mechanisms by which invasive mosquitoes can swarm new areas and expose human populations to an increased risk of disease.

Avoid How Humans get Infected by Mosquitoes

Females of most mosquito species have to bite animals to get protein so that they can develop eggs. Many pathogens have evolved to happily hitch a ride with mosquitoes in order to spread and reproduce. “When a female mosquito bites you after biting an animal or another human that is infected with these pathogens, explains Dr. Leisnham, there is a chance you could be infected. Humans are quite easy targets for many mosquitoes because they don't have feathers or thick fur. “The best ways to avoid getting bitten by mosquitoes is wear long pants, long-sleeve shirt and hat when outdoors, and minimize time outside at dawn and dusk when mosquitoes are most active” says Dr. Leisnham.

Maryland- Place to Study Exotic Mosquitoes

Dr. Leisnham is currently studying the interactive effects of climate change, land use, and invasive species on mosquito communities in Maryland. He contends that human-induced land use and climate changes often erode natural ecological processes that prevent the invasion of exotic mosquitoes, and that the erosion of these processes can lead to increased numbers of unwanted mosquito pests. Dr. Leisnham’s research studying mosquito among urban forests and residential yards is shedding light on the effects of land cover changes on the spread of invasive mosquito pests, and Maryland is an ideal location to do it. “The Eastern United States has experienced successful invasions of exotic mosquito species that transmit a range of human and animal diseases, including West Nile virus and Eastern Equine Encephalitis,” explains Dr. Leisnham. Moreover, Maryland consists of a patchwork of different land uses and will experience considerable climate change in the coming years. Dr. Leisnham’s research will seek to understand how native and exotic biodiversity affect the invasion success or failure of exotic species across environmental conditions that change with land use and climate and food resources. 

Mosquito Research Benefits

  • Help control and manage key mosquito species of public health importance. 
  • Identify human populations at particularly high risk from mosquito-borne disease. 
  • Increase our understanding of important processes helping or acting as a barrier to the invasion of exotic organisms. 
  • Shed light on how fundamental interactions between species change of environ mental gradients.