The only study of its kind in Sub-Saharan Africa is based on three
decades of historical data and has important implications for arid
countries around the world struggling with poverty and increasing health
Katherine Alexander, a veterinarian, teaches in
Virginia Tech's College of Natural Resources and Environment and
conducts research at the Blacksburg, Va., campus and at her non-profit
research center, the Center for African Resources: Animals, Communities,
and Land Use(CARACAL), in Chobe, Botswana.
study, "Climate Change Is Likely to Worsen the Public Health Threat of
Diarrhoeal Disease in Botswana," was published today in the
International Journal of Environmental Research and Public Health.
and colleagues analysed data on diarrhoeal disease from 1974, eight
years after Botswana gained independence from British rule, through
"Botswana proactively set up a health surveillance program
shortly after it became independent. Over such a long time period,
however, it was not easy locating all the historical documents
pertaining to diarrhoea case incidence," Alexander said.
such data in Africa is difficult, and this explains why long-term
studies of climate and health interactions are uncommon," she continued.
"Our work indicates that there is a critical need to identify
climate-health interactions across the continent and develop appropriate
adaptive strategies in response."
The Botswana Ministry of
Health and the Ministry of Environment Wildlife and Tourism provided
research assistance. The Wildize Foundation, an African conservation
organization, supplemented funding. Researchers Marcos Carzolio and Eric
Vance from Virginia Tech and Douglas Goodin from Kansas State
University co-authored the study.
Main cause of childhood deaths
disease is an important health challenge, accounting for the majority
of childhood deaths globally and the second highest in Botswana,"
Alexander said. "Our findings suggest that climate change will increase
the occurrence of diarrhoea and the burden of disease among vulnerable
populations in Botswana and similarly affected regions."
is an arid, landlocked country in southern Africa with a subtropical
climate of distinct wet and dry seasons. Alexander and her co-authors
evaluated monthly reports of diarrhoeal disease among patients treated
at Botswana health facilities since 1974 and compared that data with
climatic variables over that same period.
"Our analysis suggests
that forecasted climate change increases in temperature and decreases in
precipitation for the region are likely to increase dry season
diarrhoeal disease incidence, while diarrhoeal disease incidence in the
wet season is likely to decline," Alexander explained.
Diarrhoeal disease peaks in hot, dry weather
case incidence peaks in both the wet and dry seasons in Botswana with
mean case incidence 20% higher on average in the dry season over the wet
"We were not expecting diarrhoeal disease to be worse in the dry season," Alexander pointed out.
dry season diarrhoeal disease peaks occur during the hottest and driest
times of the year, conditions that can increase fly activity and
density. This is significant, as flies can be important in the
transmission of diarrhoeal-disease-causing microorganisms."
believes flies may provide an important dry season amplifying influence
on factors already contributing to diarrhoeal disease. "It is an
important area of research that we will be pursuing," she added.
results identify significant climate-health interactions and highlight
the need for an escalated public health focus on controlling diarrhoeal
disease in Botswana," she continued. "Understanding the potential health
impacts of climate change in low-income countries will be essential to
developing mitigation and adaptive strategies designed to protect these
vulnerable populations expected to be impacted the hardest but least
able to adapt."
"While our work identifies important
climate-health interactions and increased vulnerability of Botswana to
forecasted changes in regional climate," Alexander cautioned, "it is
important to remember that this does not account for affects of
non-climatic factors such as future improvements in sanitation
infrastructure and hygiene. The impact of forecasted climate change on
this disease syndrome is likely to be significantly reduced if present
day public health deficiencies are fully identified and addressed."
is essential, however, that we include affected communities in
identifying climate change preparedness," Alexander emphasized. "Lack of
socio-cultural considerations in public health planning can result in
locally applied interventions being non-sustainable."
Poor vulnerable to environmental change
climate variability as a determinant of infectious disease is
increasingly seen as a cornerstone of climate change preparedness and an
urgent area of need in Africa and elsewhere around the world.
of the threat of climate change on health results from our
vulnerabilities to environmental change. These vulnerabilities are
primarily associated with the poor, who are most dependent on the
environment and least able to adapt to changes in these systems," she
explained. "If we address current community health deficiencies now,
climate change impacts are not likely to have such important and
potentially devastating consequences in the future."
the magnitude of Alexander's work in Botswana, she is one of three
scholars selected as an African regional expert by the World Health
Organization and the Convention on Biological Diversity secretariat to
participate in a regional workshop in Mozambique April 2-5. As a
specialist in disease ecology with associated ecological and human
dimensions, she will make a presentation to leaders from various African
countries on integrating health and biodiversity in policy and planning
"Kathy is a brilliant scholar who successfully connects
her many skills to people in Botswana," said Paul Winistorfer, dean of
Virginia Tech's College of Natural Resources and Environment. "She
recognizes that her most important goal is to improve the lives and
livelihood of these people, while respecting the human-wildlife
interaction that is coupled to environmental sustainability."