Nav: Home

In urban Baltimore, poor neighborhoods have more mosquitoes

June 30, 2017

(Millbrook, NY) A new study published in the Journal of Medical Entomology reports that in Baltimore, Maryland, neighborhoods with high levels of residential abandonment are hotspots for tiger mosquitoes (Aedes albopictus). This environmental injustice may leave low-income urban residents more vulnerable to mosquito-borne disease.

Shannon LaDeau, a disease ecologist at the Cary Institute of Ecosystem Studies and senior author on the paper, explains, "We are interested in how land cover, microclimate, and socioeconomics influence the distribution of tiger mosquitoes. In Baltimore and other temperate cities, the interplay of these factors determines when and where mosquitoes emerge and the extent to which they pose a risk to people."

Native to Asia, tiger mosquitoes arrived in the US in the 1980s, likely as stowaways on imported tires. They have quickly spread throughout the South and Northeast, where they thrive in cities. Unlike native mosquitoes, they feed during daylight hours and are known for living in close association with people.

Lead author Eliza Little, a doctoral candidate in the Department of Environmental Health Sciences at Columbia University, explains, "Tiger mosquitoes are highly tolerant and can reproduce in very small pools of water; a cap of water will suffice. They are known to transmit diseases such as dengue and chikungunya, with documented cases in Asia and Europe. They also have the potential to spread Zika."

The research team, which included scientists from the University of Maryland and Rutgers University, spent three years monitoring mosquito activity in five west Baltimore neighborhoods. Study sites spanned a gradient of low, medium, and high socioeconomic status neighborhoods. At each site, 33 blocks were identified as predominantly residential, excluding businesses, schools, and large apartment complexes.

Block-scale surveillance of mosquito breeding habitat was conducted three times during each season (in June, July, and September). Every three weeks, from May to September, adult mosquitoes were also sampled. Climate data from a NOAA station at the Maryland Science Center was used to track how rainfall influenced the development of larval mosquitoes.

To reveal how landscape features and vegetation influence mosquito prevalence, target neighborhoods were mapped using block-by-block surveys and Landsat satellite imagery. During ground surveys, researchers counted trees, abandoned buildings (officially condemned or with 148 boarded-up entry), parks, vacant lots, grassy areas, and trash with the potential to serve as breeding habitat.

High vegetation cover was found in both low and high income neighborhoods, but its impact on mosquito abundance differed. More mosquitoes were found in lower socioeconomic areas because vacant lots and abandoned buildings provide more breeding sites. Infrequent garbage removal is another issue, giving rise to semi-permanent dumping sites that attract mosquitoes.

The correlation between a neighborhood's socioeconomic status and mosquito abundance wasn't static. In low-income areas, rain-filled trash, abandoned and decaying properties, and overgrown lots create mosquito breeding habitat. In higher socioeconomic areas, mosquitoes are supported by residents who water their plants and lawns during the summer.

LaDeau explains, "In a city like Baltimore, hot, dry conditions should cause mosquito populations to decline. Instead, in higher income neighborhoods, residents water their yards and enable mosquito populations to survive. That said, overall, our surveys found much larger mosquito populations in lower income neighborhoods."

"This study highlights the dual needs for personalized mosquito control on a lot-by-lot basis and public education across different socioeconomic neighborhoods to implement effective control strategies," Little notes. Adding, "Our work can also inform urban greening strategies. There can be unintended consequences when green spaces are added to cities without first removing mosquito-sustaining containers."

By understanding the environmental conditions that give rise to mosquito populations, researchers can better predict and manage mosquitoes in urban areas, reducing environmental injustices and protecting public health.

LaDeau concludes, "This summer, if you want to reduce mosquito numbers, one the best things you can do is reduce water-holding containers in your community. After a rainfall, do a quick survey of your yard or neighborhood and address sites where water pools. Planters, clogged gutters, neglected pet dishes and bird baths, and trash all provide great tiger mosquito breeding grounds."
-end-
This study was made possible, in part, by support from the National Science Foundation, the Parks & People Foundation, the US Department of Agriculture, and the National Institutes of Health. It is a contribution to the Baltimore Ecosystem Study Long Term Ecological Research (BES LTER) Program.

Citation

E. Little, D. Biehler, P. T. Leisnham, R. Jordan, S. Wilson, S. L. LaDeau; Socio-Ecological Mechanisms Supporting High Densities of Aedes albopictus (Diptera: Culicidae) in Baltimore, MD. J Med Entomol 2017 tjx103. doi: 10.1093/jme/tjx103

The Cary Institute of Ecosystem Studies is one of the world's leading independent environmental research organizations. Areas of expertise include disease ecology, forest and freshwater health, climate change, urban ecology, and invasive species. Since 1983, Cary Institute scientists have produced the unbiased research needed to inform effective management and policy decisions.

Cary Institute of Ecosystem Studies

Related Mosquitoes Articles:

In Baltimore, lower income neighborhoods have bigger mosquitoes
Low-income urban neighborhoods not only have more mosquitoes, but they are larger-bodied, indicating that they could be more efficient at transmitting diseases.
Mosquitoes more likely to lay eggs in closely spaced habitats
Patches of standing water that are close together are more likely to be used by mosquitoes to lay eggs in than patches that are farther apart.
Why do mosquitoes choose us? Lindy McBride is on the case
Most of the 3,000+ mosquito species are opportunistic, but Princeton's Lindy McBride is most interested in the mosquitoes that scientists call 'disease vectors' -- carriers of diseases that plague humans -- some of which have evolved to bite humans almost exclusively.
Biting backfire: Some mosquitoes actually benefit from pesticide application
The common perception that pesticides reduce or eliminate target insect species may not always hold.
What makes mosquitoes avoid DEET? An answer in their legs
Many of us slather ourselves in DEET each summer in hopes of avoiding mosquito bites, and it generally works rather well.
How mosquitoes smell human sweat (and new ways to stop them)
Female mosquitoes are known to rely on an array of sensory information to find people to bite, picking up on carbon dioxide, body odor, heat, moisture, and visual cues.
Forecasting mosquitoes' global spread
New prediction models factoring in climate, urbanization and human travel and migration offer insight into the recent spread of two key disease-spreading mosquitoes -- Aedes aegypti and Aedes albopictus.
Medicating mosquitoes to fight malaria
Mosquitoes that landed on surfaces coated with the anti-malarial compound atovaquone were completely blocked from developing Plasmodium falciparum, the parasite that causes malaria, according to new research led by Harvard T.H.
Mosquitoes can hear from longer distances than previously thought
While most hearing experts would say an eardrum is required for long distance hearing, a new study from Binghamton University and Cornell University has found that Aedes aegypti mosquitos can use their antennae to detect sounds that are at least 10 meters away.
Urbanization changes shape of mosquitoes' wings
Research shows that rapid urbanization in São Paulo City, Brazil, is influencing wing morphology in the mosquitoes that transmit dengue and malaria.
More Mosquitoes News and Mosquitoes Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.