Image courtesy Dr. Sadie Ryan
Image courtesy Dr. Sadie Ryan

GAINESVILLE, Fla. – A larger portion of Africa is currently at high risk for malaria transmission than previously predicted, according to a new University of Florida mapping study.

Under future climate regimes, the area where the disease can be transmitted most easily will shrink, but the total transmission zone will expand and move into new territory, according to the study, which appears in the current issue of the journal Vector-Borne and Zoonotic Diseases.

By 2080, the study shows, the year-round, highest-risk transmission zone will move from coastal West Africa, east to the Albertine Rift, between the Democratic Republic of Congo and Uganda. The area suitable for seasonal, lower-risk transmission will shift north into coastal sub-Saharan Africa.

Most striking, some parts of Africa will become too hot for malaria.

The overall expansion of malaria-vulnerable areas will challenge management of the deadly disease, said lead author Sadie Ryan, an assistant professor of geography at the University of Florida who also is affiliated with UF’s Emerging Pathogens Institute.

Malaria will arrive in new areas, posing a risk to new populations, she said, and the shift of endemic and epidemic areas will require public health management changes.

“Mapping a mathematical predictive model of a climate-driven infectious disease like malaria allows us to develop tools to understand both spatial and seasonal dynamics, and to anticipate the future changes to those dynamics,” Ryan said.

Cerebral malaria, caused by the parasite Plasmodium falciparum transmitted by the Anopheles gambiae mosquito, is the most deadly form of the disease, killing around 584,000 people each year. Malaria can cause organ failure, unconsciousness, and coma, if left untreated, and is a major cause of decreased economic productivity in affected regions.

The study uses a model that takes into account the real, curved, physiological responses of both mosquitoes and the malaria parasite to temperature. This model shows an optimal transmission temperature for malaria that, at 25 degrees Celsius, is 6 degrees Celsius lower than previous predictive models.

This work will play an important role in helping public health officials and NGOs plan for the efficient deployment of resources and interventions to control future outbreaks of malaria and their associated societal costs, Ryan said.

The collaborative research team includes experts in epidemiology, public health, ecology, entomology, mathematical modeling and geography. In addition to Ryan, other team members are Amy McNally (NASA), Leah Johnson (University of South Florida), Erin A. Mordecai (Stanford University), Tal Ben-Horin (Rutgers), Krijn Paaijmans (Universitat de Barcelona) and Kevin D. Lafferty (University of California, Santa Barbara).

The work expands upon the team’s prior work at the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara.

RYAN – Mapping Physiological Suitability Limits for Malaria in Africa Under Climate Change

Ryan Sadie J., McNally Amy, Johnson Leah R., Mordecai Erin A., Ben-Horin Tal, Paaijmans Krijn, and Lafferty Kevin

Article first published online: 18 Nov 2015 Vector-Borne and Zoonotic Diseases

DOI: 10.1089/vbz.2015.1822

ABSTRACT: We mapped current and future temperature suitability for malaria transmission in Africa using a published model that incorporates nonlinear physiological responses to temperature of the mosquito vector Anopheles gambiae and the malaria parasite Plasmodium falciparum. We found that a larger area of Africa currently experiences the ideal temperature for transmission than previously supposed. Under future climate projections, we predicted a modest increase in the overall area suitable for malaria transmission, but a net decrease in the most suitable area. Combined with human population density projections, our maps suggest that areas with temperatures suitable for year-round, highest-risk transmission will shift from coastal West Africa to the Albertine Rift between the Democratic Republic of Congo and Uganda, whereas areas with seasonal transmission suitability will shift toward sub-Saharan coastal areas. Mapping temperature suitability places important bounds on malaria transmissibility and, along with local level demographic, socioeconomic, and ecological factors, can indicate where resources may be best spent on malaria control.

Read the full publication at Vector-Borne and Zoonotic Diseases 

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GEO3250 GEO6255 Climatology

Learn the science behind climate change
Analyze data for past/future climates and extreme events
Create a video about climate change
Qualifies for the Certificate in Meteorology and Climatology
Good prep for MET 4532/6530 Hurricanes and/or MET 4572/6752 Atmospheric Data Analysis offered Fall 2016

GEO2242 Extreme Weather
GEO2242 Extreme Weather

This course will introduce students to the basic concepts of the science of weather and climate and current scientific developments in such areas as extreme weather prediction, global climate change, and improved forecasting of events. In addition, the course will address the impact of extreme climate and weather events on society and the environment. The goal of this course is to bring weather and climate alive through required readings, assignments, video presentations, satellite technologies, class activities and computer simulations. Weekly readings will be enhanced through the use of such multimedia products and class activities, reinforcing concepts related to extreme climate and severe weather events.