Dr. Peter Waylen saw the first fruits of a collaboration with Dr. Chris Annear (Anthropology, Hobart and William Smith Colleges, Geneva, NY) in a paper entitled Socializing the rain: human adaptation to ecological variability in a fishery, Mweru-Luapula, Zambia, which appeared during the summer in the Journal of Political Ecology. Chris is a young Anthropologist who studied the fishers and fish trader on Lake Mweru and their families. Pete was able to help Chris better understand the fluctuations in lake level and the number and variety of fish caught by considering long term changes in rainfall inputs to the upstream basin. This is a nice example of two people from very disparate disciplinary backgrounds coming together to work on a problem combining both the human and physical dimensions. The second coauthored paper, Interannual Hydroclimatic Variability of the Lake Mweru Basin, Zambia, dealing more with the hydroclimatological characteristics of the basin was published in the journal Water, and brought UF Geography alumna Dr. Erin Bunting into the collaboration.
Christopher M. Annear, Peter R. Waylen
Article first published online: 23 AUG 2019 Journal of Political Ecology
ABSTRACT: Rainfall drives fishery fertility in Mweru-Luapula, thus rainfall variability contributes to frequent changes in fishing catches. Fishers and traders have adapted their institutions to this variable ecology in a variety of ways, including learning to read the fishery for productive periods and practicing multiple modes of income procurement. By accurately identifying inter-annual, inter-decadal, and longer spans of rainfall trends, future high and low yields can be forecast. This article presents and analyzes annual rainfall in the fishery from 1916-1992 and quantitative fish market data comprised of observed fish catch numbers by species in three markets from September 2004 to September 2005. It uses political ecology to better understand fish production, trade, and subsistence in this South-Central African freshwater fishery. We combine qualitative analysis of fisher and marketer perceptions of the fishery and knowledge of rainfall patterns to show how human behavior is not “tragically” driven, but instead based on the state of the ecological, sociocultural, and socioeconomic environment at a given time.
Read the full publication at Journal of Political Ecology
GAINESVILLE – Blood sucking insects such as the Yellow fever mosquito, Aedes aegypti, are more than just a nuisance in Ecuador, they also spread diseases such as dengue fever, chikungunya and Zika. A warming world means that public health officials must decide where to direct surveillance and mosquito control efforts not only today, but also decades down the road given dramatic shifts in mosquito habitat that will take place thanks to climate change.
Ecuadorian agencies now have a powerful helping hand: a recent paper in PLoS Neglected Tropical Diseases provides detailed maps forecasting where mosquitoes – and diseases – are likely to be in a warmer future.
The new work from the University of Florida’s Quantitative Disease Ecology & Conservation Lab Group (QDEC Lab) and the Emerging Pathogens Institute assesses the current and future geographic distribution of Ae. aegypti throughout Ecuador. The study was led by PhD Candidate Ms. Cat Lippi and is the result of a long-term collaboration with SUNY Upstate Medical University and the Ecuadorian Ministry of Health. Lippi’s committee chair, EPI researcher and QDEC founder Dr. Sadie Ryan, also contributed to the project, as did EPI investigator Dr. Jason Blackburn.
The research team repurposed historic larval mosquito surveillance data collected by the Ministry of Health between 2000 and 2012 in Ecuadorian households to predict where Ae. aegypti may occur in areas that have not yet been surveyed. Aedes aegypti mosquitoes are important because they are a vector for several different mosquito-borne diseases and are able to reproduce in small quantities of standing water, making them common in urban settings. The research team used environmental and climate modeling to analyze how areas currently suitable for the mosquito may shift in the future as a result of climate change.
“We wanted to show the Ministry of Health in Ecuador where disease-carrying mosquitoes might occur in the future,” Lippi says. By analyzing the environmental and climactic characteristics associated with where mosquitoes occur in Ecuador today, the team extrapolated where mosquitoes may occur in 2050 under a range of climate change scenarios and used the presence of these mosquitoes as a proxy for where disease would occur.
The models show that Ae. aegypti are likely to expand their range into regions of transitional elevation along the Andes mountain range by midcentury. The expanded habitat includes the portion of mountainous area where valley floors give way to a mountain’s lower slopes. The higher reaches of the Andes famed peaks are expected to remain protected pockets that will still be too cool, even with extreme warming, for Ae. aegypti to survive. At the same time, changing climate will reduce the mosquito’s range in the eastern portion of the country’s Amazon.
“When there is a population that has never been exposed to pathogens like dengue or Zika, they don’t have any immunity, and that population will be vastly more susceptible to an acute outbreak,” Lippi says. “There are thousands of Ecuadorians who will be exposed to mosquitoes in the future who have never had to deal with them before.”
The team will share their results with the Ecuadorian Ministry of Health, which will use the data to prepare for the future. Previous work through the team’s collaboration with Ecuador’s Ministry of Health showed that local knowledge and attitudes are significantly associated with the risk of Ae. aegypti mosquitoes in households in Ecuador, although effects on actual dengue fever risk are less clear. Mosquito-borne diseases pose a serious threat to public health throughout Ecuador and Latin America, where dengue alone accounts for an estimated 16 million infections occurring in the Americas each year.
“Our work gives their health department good forewarning of where to focus their preparations to prevent future outbreaks, and this will help them to conserve limited resources,” Lippi says. Preparations may include educational campaigns on using insect repellent, and window and door screens, as well as how to safely store household water in covered containers. The government can also coordinate spraying efforts to reduce mosquito larvae in the environment.
“Of course we expect to see changes in habitat and species’ ranges due to future climate change,” Lippi says. “But what this study addresses is the question of where those changes will occur, and how severe those changes may be, all within the context of disease risk to people.”
Un nuevo estudio de la Universidad de Florida (Estados Unidos) sugiere que los mosquitos que transmiten enfermedades podrían infectar a poblaciones humanas en Los Andes ecuatorianos debido al cambio climático
Comunidades en Latino América tienen el desafío de reducir la exposición a mosquitos que transmiten enfermedades, como el Aedes aegypti. En Ecuador, este mosquito es más que una molestia. El Aedes aegypti trasmite víruses que causan enfermedades de alta consideración para la salud pública incluyendo dengue, chikungunya y Zika. Dónde el Ministerio de Salud Publica (MSP) podría enfocar los esfuerzos de vigilancia y control de estos mosquitos, hoy y en el futuro, tomando en cuenta el cambio climático?
Un nuevo estudio del grupo, Ecología de Enfermedades y Conservación Cuantitativa (QDEC), de la Universidad de Florida, analiza la distribución geográfica del Aedes aegypti a través de todo Ecuador. El proyecto fue dirigido por Cat Lippi, estudiante de PhD de QDEC, y es el resultado de una colaboración a largo plazo con la Universidad del Estado de New York y Universidad Médica de “Upstate” (SUNY UPSTATE) y el MSP del Ecuador. El equipo de investigadores usó datos históricos de vigilancia de mosquitos recolectados por el MSP para predecir lugares donde Aedes aegypti podría estar presente. Áreas que no se ha inspeccionado de una manera activa y áreas donde podría estar presente en el futuro bajo condiciones de cambio climático. Modelos de “nicho ecológico” fueron creados usando información sobre lugares con la presencia actual del moquito y con variables básicos del ambiente. Los modelos fueron desarrollados usando condiciones climatológicas actuales y futuras, hasta el año 2050.
Este estudio muestra que lugares con elevaciones intermedias a lo largo de Los Andes pueden convertirse en zonas mas asequibles para la presencia de Aedes aegypti en el año 2050. Este descubrimiento sugiere que la población que actualmente viven en estas zonas de transición puede correr el riesgo, en el futuro, de ser expuesto a enfermedades transmitidas por mosquitos, como resultado de cambio climático. Los autores reportan que aumentará la población con riesgo de exposición por más de 12,000 personas bajo los escenarios extremos de cambio climático. Al mismo tiempo, los investigadores identificaron áreas que pueden ser menos propicias para los mosquitos, como la cuenca de la Amazonia.
Actualmente, la mayor parte de las personas que viven en Los Andes están protegidos por las enfermedades transmitidos por mosquitos debido a las altas elevaciones, lo que produce un ambiente frio y no apto para los moquitos. En situaciones extremas de cambio climático, los mosquitos pueden invadir nuevas lugares con elevación de 900 metros más alto que los lugares en actuales condiciones climatológicas. “Las personas que vivan en esta zona de expansión de enfermedades pueden ser más susceptibles a futuros brotes de enfermedades debido a varios factores, incluyendo falta de inmunidad debido a exposición previa al patógeno y falta de conocimiento y costumbres asociados con la prevención de mosquitos y costumbres de protección personal, como el uso de repelente,” indica Lippi. Estudios previos en colaboración con el MSP del Ecuador mostraron que el conocimiento y actitudes de las poblaciones locales están asociados con el riesgo de la presencia de Aedes aegypti en hogares en Machala. Se recomienda estudios en estos nuevas áreas de futuro riesgo.
Las enfermedades transmitidas por mosquitos son una amenaza para la salud pública en toda Latinoamérica, donde dengue causa aproximadamente 16 millones de infecciones anualmente. Estudios como éstos enfatizan la importancia de incorporar la ciencia de “Geografía de la salud” dentro de los estándares de la práctica de la educación pública, proveyendo información más precisa a las agencias de salud pública para mejorar el uso de escasos recursos para el de control de estas enfermedades y para desarrollar intervenciones de control vectorial y de educación pública en lugares específicos.
Media contact: Mike Ryan Simonovich
Over the past 25 years that I have been conducting environmental research in the Amazon, I have witnessed the the ongoing destruction of the world’s biggest rainforest. Twenty percent of it has been deforested by now – an area larger than Texas.
I therefore grew hopeful when environmental policies began to take effect at the turn of the millennium, and the rate of deforestation dropped from nearly 11,000 square miles per year to less than 2,000 over the decade following 2004.
But a new political climate in Brazil, which set in even before President Jair Bolsonaro took office in January 2019, has led to a recent increase in the pace of rainforest felling. And Bolsonaro, a former army officer, made Amazonian development a core campaign pledge.
Read the whole story in The Conversation.
Will the Extreme Rain Fall Mainly on the Plains? Rainfall Scenarios Under Climate Change for Oklahoma and Texas
Speaker: Dr. Esther Mullens
Assistant Professor, Department of Geography, University of Florida
Thursday, September 20, 2018
2:50-3:50 PM (Period 8)
Turlington Hall Room 3012
University of Florida
All are welcome to attend.
Marta Strecker Shocket, Sadie J Ryan, Erin A Mordecai
Article first published online: 28 AUG 2018 eLife
ABSTRACT: Thermal biology predicts that vector-borne disease transmission peaks at intermediate temperatures and declines at high and low temperatures. However, thermal optima and limits remain unknown for most vector-borne pathogens. We built a mechanistic model for the thermal response of Ross River virus, an important mosquito-borne pathogen in Australia, Pacific Islands, and potentially at risk of emerging worldwide. Transmission peaks at moderate temperatures (26.4°C) and declines to zero at thermal limits (17.0 and 31.5°C). The model accurately predicts that transmission is year-round endemic in the tropics but seasonal in temperate areas, resulting in the nationwide seasonal peak in human cases. Climate warming will likely increase transmission in temperate areas (where most Australians live) but decrease transmission in tropical areas where mean temperatures are already near the thermal optimum. These results illustrate the importance of nonlinear models for inferring the role of temperature in disease dynamics and predicting responses to climate change.
Read the full publication at eLife.
GAINESVILLE, FL – New model that accurately predicts patterns of mosquito-borne Ross River virus epidemics could help prepare for the impact of climate change.
Scientists have built a model that predicts how temperature affects the spread of Ross River virus, a common mosquito-borne virus in Australia, according to a report in the journal eLife.
The research demonstrates the importance of using temperature to predict epidemics of mosquito-borne diseases and could help public health bodies prepare for the impact of climate change on the spread of tropical diseases worldwide.
“Scientists are realising that warmer temperatures mean longer mosquito seasons and mosquitoes entering new regions where it was previously too cold for them to survive,” says senior author Erin Mordecai, Assistant Professor in Biology at Stanford University’s School of Humanities and Sciences. “Warm temperatures also speed up the biological processes that help mosquitoes spread viruses. But working out the precise effect of temperature on different stages of mosquito growth and spread of viruses is tricky, because so many factors are involved.”
Australia and the Ross River virus (RRV) offer an ideal opportunity to study the effects of temperature on disease transmission. RRV infects between 2,000–9,000 people each year in Australia and causes long-term joint pain and disability. Most people live in cities ranging in latitude from the north to the south of the country. Each season, as the temperature rises, RRV epidemics move from the subtropical north to temperate south.
The team used two species of mosquito most responsible for RRV outbreaks in Australia to build a model using laboratory data on traits such as mosquito growth, survival, bite rate and infectiousness in response to different temperatures. “Our model correctly predicted that RRV is endemic across tropical Northern Australia year-round, and is seasonally epidemic in the cooler regions of Southern Australia,” explains Sadie Ryan, Associate Professor of Medical Geography at the University of Florida, and second author of the study. “When human population data was added into the model, its prediction of seasonal patterns matched recorded human cases of RRV.”
The model determined that the optimal temperature for RRV spread was 26°C (80°F) and transmission would be limited at temperatures below 17°C (63°F) and above 32°C (89°F), which matches current patterns of disease. Mosquito lifespan was the most important temperature-dependent factor limiting transmission, and fertility and survival were prohibiting factors at temperatures that were too low or high for transmission. As transmission is limited by temperatures that are too cold and too hot, it may increase in some locations as a result of climate warming, while decreasing in others.
“Our study provides strong evidence that temperature drives infection patterns at the continent-wide and seasonal levels,” says first author Marta Shocket, Postdoctoral Scientist in Stanford’s Biology Department. “In the short term, our work will help researchers build better statistical models for RRV which can be used to make more specific predictions based on climate change. In the long term, it should help mosquito control agencies better plan for the future and may provide further evidence of the need to combat climate change.”
Blanka Tesla, Leah R. Demakovsky, Erin A. Mordecai, Sadie J. Ryan, Matthew H. Bonds, Calistus N. Ngonghala, Melinda A. Brindley, Courtney C. Murdock
Article first published online: 15 AUG 2018 Proceedings of the Royal Society B
ABSTRACT: Temperature is a strong driver of vector-borne disease transmission. Yet, for emerging arboviruses we lack fundamental knowledge on the relationship between transmission and temperature. Current models rely on the untested assumption that Zika virus responds similarly to dengue virus, potentially limiting our ability to accurately predict the spread of Zika. We conducted experiments to estimate the thermal performance of Zika virus (ZIKV) in field-derived Aedes aegypti across eight constant temperatures. We observed strong, unimodal effects of temperature on vector competence, extrinsic incubation period and mosquito survival. We used thermal responses of these traits to update an existing temperature-dependent model to infer temperature effects on ZIKV transmission. ZIKV transmission was optimized at 29°C, and had a thermal range of 22.7°C–34.7°C. Thus, as temperatures move towards the predicted thermal optimum (29°C) owing to climate change, urbanization or seasonality, Zika could expand north and into longer seasons. By contrast, areas that are near the thermal optimum were predicted to experience a decrease in overall environmental suitability. We also demonstrate that the predicted thermal minimum for Zika transmission is 5°C warmer than that of dengue, and current global estimates on the environmental suitability for Zika are greatly over-predicting its possible range.
Read the full publication at Proceedings of the Royal Society B