Tanzania is enlisting climate data in a new approach to curbing malaria.
Enhancing National Climate Services (ENACTS), a system established by the Tanzania Meteorological Agency in conjunction with the US-based International Research Institute for Climate and Society, is designed to identify long-term drivers of the disease by compiling historical climate data and making it available for analysis by health policy-makers.
Malaria is a major public health concern in Tanzania. More than 10 million cases are still reported annually among the population of about 48 million. This is despite the government's efforts to scale up preventive measures over the past decade, which contributed to a declining trend of the disease in children under five years old. In 2007, 18 percent of those under five contracted the disease; in 2011 it was 10 percent.
Augustine Kanemba, the Tanzania Meteorological Agency's principal meteorologist, said climate variability is an important driver of malaria because variations in rainfall, temperature and humidity affect the spread of the disease.
"Malaria breeding grounds are often wet areas, so reproduction of mosquitoes very much depends on the availability of water and temperature ranging between 25 and 30 degrees Celsius," he said.
According to Kanemba, it has been difficult to use climate data in Tanzania to track health threats because of a decline in the number of weather stations. Those that remain are unevenly distributed, with most of them located along main roads.
"Lack of coverage tends to be worse in rural areas where livelihoods are the more vulnerable to climate variability," he said. "We hope that this platform will bring relevant information close to the people."
ENACTS combines ground observations of rainfall and temperature with monitoring by remote-sensing satellite technology to create records which can be analysed to understand the climatic conditions in which outbreaks of diseases have occurred, and to help predict new outbreaks.
30 YEARS OF RAINFALL AND TEMPERATURES
The programme has produced an unprecedented 30-year historical series of rainfall and temperature data - with ten measurements per day - for every 10km grid across the country to help health experts track malaria distribution.
The meteorological agency also has created three online "map rooms" which provide user-friendly tools for seeing and analysing the information.
Kanemba said climate information has the potential to inform a wide range of health decisions by improving understanding of how diseases are transmitted and helping to prevent them.
Many parts of Africa with tropical climates and high rainfall variability are susceptible to malaria. Recent studies suggest the pattern of disease transmission varies considerably when extreme climatic events occur.
Agnes Kijazi, the meterological agency's director general, said increasingly unusual weather circumstances in areas susceptible to malaria highlight the growing need for early warning systems to help health authorities respond quickly.
"Because malaria is highly associated with climate, weather-based epidemic warning systems can help to reduce the impacts," she said.
BED NETS AND SPRAYING
According to officials from the National Malaria Control Programme, which is under the Ministry of Health, climate information linked to the spread of vector-borne diseases would help the government to carefully plan public health interventions such as distributing insecticide-treated bed nets in new malaria breeding grounds as well as embarking on insecticide spraying campaigns.
Malaria remains a major cause of death and illness worldwide. It is widely identified as one of the diseases most likely to be affected by changes in climate variables because its transmission dynamics are particularly sensitive to environmental conditions.
According to the World Health Organization, around 219 million people worldwide caught the disease in 2010, the majority in sub-Saharan Africa. Of those infected, 660,000 died.
Analysts say that while the usefulness of understanding climate conditions in health decision-making is increasingly being recognised, few African countries have the capability to routinely provide the health community with information that can be integrated into decision-making.
That means services often don't reach areas "where such services are often needed most," said Kanemba.
According to an IRI study published in February, the ENACTS approach may increase Tanzania's capacity to identify long-term drivers of disease and support prevention measures.
Sonia Altizer, a researcher at the University of Georgia in the United States, said that modelling how disease systems respond to climate factors could help public health officials and environmental managers predict and mitigate the spread of deadly diseases.
"We'd like to be able to predict, for example, that if the climate warms by a certain amount, then in a particular host-parasite system we might see an increase from one to two transmission cycles per year," Altizer wrote in Science magazine, adding that "we'd also like to try to tie these predictions to actions that might be taken."
According to Zul Premji, a malaria researcher at Muhimbili University of Health and Allied Sciences in Dar es Salaam, understanding the factors that contribute to the load of disease cases is critical to efforts to roll back diseases.
"A more effective way of merging climate information into malaria policy-making could help us solve these challenges," he said.
Kizito Makoye is a journalist based in Dar es Salaam.