Climate change responsible for diarrhoe-study

OARABILE MOSIKARE
Staff Writer | Thursday April 4, 2013 00:00

The study was led by Associate Professor Kathleen Alexander of Virginia Tech who found that climate drives a large part of diarrheal disease and exposes vulnerable communities to infection. Funded by the US National Science Foundation, it is one of a kind for Sub-Saharan Africa and is based on three decades of historical data. It has important implications for arid countries that struggle with poverty and increasing health challenges.

Alexander, a veterinarian, teaches at Virginia Tech's College of Natural Resources and Environment and conducts research at the Blacksburg, Virginia campus as well as at her nonprofit research centre, the Centre for African Resources: Animals, Communities, and Land Use (CARACAL), in Botswana's Chobe.

Alexander's research study, 'Climate Change is Likely to Worsen the Public Health Threat of Diarrheal Disease in Botswana,' was published last week in the International Journal of Environmental Research and Public Health.Alexander and colleagues analysed data on diarrheal disease from 1974, through to 2003. 'Botswana proactively set up a health surveillance programme shortly after it became independent,' Alexander said.

'Over such a long period, however, it was not easy locating all documents pertaining to diarrhoea case incidence.Finding such data in Africa is difficult, and this explains why long-term studies of climate and health interactions are uncommon.' She said their work indicates that there is a critical need to identify climate-health interactions across the continent and develop appropriate adaptive strategies in response.

The ministries of health and the environment, wildlife and tourism provided research assistance. The Wildlife Foundation, an African conservation organisation, supplemented funding.Researchers Marcos Carzolio and Eric Vance from Virginia Tech and Douglas Goodin from Kansas State University co-authored the study.

'Diarrheal disease is an important health challenge, accounting for the majority of childhood deaths globally and the second highest in Botswana,' said Alexander. '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.'

Alexander and her co-authors evaluated monthly reports of diarrheal 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 diarrheal disease incidence, while diarrheal disease incidence in the wet season is likely to decline,' Alexander explained.

Diarrheal case incidence peaks in both the wet and dry seasons in Botswana, with mean case incidence 20 percent higher on average in the dry season over the wet season. 'We were not expecting diarrheal disease to be worse in the dry season,' Alexander pointed out. 'These dry season diarrheal 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 diarrheal disease-causing microorganisms.'

Alexander believes flies may provide an important dry season amplifying influence on factors already contributing to diarrheal disease. 'It is an important area of research that we will be pursuing,' she added.'Our results identify significant climate-health interactions and highlight the need for an escalated public health focus on controlling diarrheal disease in Botswana.

'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.'

The study has identified 'important climate-health interactions and increased vulnerability of Botswana to forecasted changes in climate'. Because of the magnitude of Alexander's work in Botswana, she is one of three scholars selected as an African regional expert by the World Health Organisation and the Convention on Biological Diversity secretariat to participate in a regional workshop in Mozambique that began on April 2 until April 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 efforts.'Kathy is a brilliant scholar who connects her many skills to people in Botswana,' said Paul Winistorfer, dean of Virginia Tech's College of Natural Resources and Environment.

'She recognises that her most important goal is to improve the livelihood of these people, while respecting the human-wildlife interaction that is coupled with environmental sustainability.'