Climate change research to prevent sleeping sickness outbreaks in Tanzania

TDR news item
1 December 2015

An innovative research approach is underway in Tanzania that may help communities adapt to the devastating effects of climate change. Unexpected weather patterns, such as increasing temperatures, late rainfall onset and droughts are affecting livelihoods, food security and health.

According to WHO estimates, climate change is already causing tens of thousands of deaths every year - from shifting patterns of disease, from extreme weather events, such as heat waves and floods, and from the degradation of air quality, food and water supplies, and sanitation.

One of the country’s most vulnerable populations to climate change is the Maasai pastoralists living near the border of Tanzania and Kenya. TDR is working with the International Development Research Centre of Canada to coordinate research that brings together the pastoralists with international and national scientists to identify sustainable solutions.

The Maasai pastoralists in northern Tanzania are particularly vulnerable to the combined effects of climate change and zoonotic diseases (diseases that can be passed from animals to humans) because they live close to large wildlife populations that can act as reservoirs of infection, and compete for access to water and food for their cattle.

Cattle are the lifeblood of the Maasai tribe. Their milk is a critical source of income and nutrition. However, persistent droughts have reduced pasture growth in recent years leaving the fields dry and dusty. As a result men are taking their herds further and further away to get good pasture.

The Maasai are migrating to northern Tanzania’s woodlands where large wildlife live and are exposing their cattle to human African Trypanosomiasis or sleeping sickness, which has been dormant for years. Sleeping sickness can dry up the cattle’s milk permanently, and impact the community’s health.

Human African Trypanosomiasis or sleeping sickness threatens millions of people in 36 sub-Saharan Africa countries where there are tsetse flies that transmit the disease. Like the Maasai, the people most exposed to these flies and therefore the disease, live in remote rural areas and depend on agriculture, fishing, animal husbandry or hunting.

Beyond sleeping sickness, rabies, bacterial infections and diseases carried by ticks are also impacting the Maasai. Yet, these zoonotic diseases do not get much attention. Merging the sciences of the flies, parasites, the environment, water and climate, TDR is working with the community to research and develop solutions.

The study, launched in 2013, is working to identify the safest areas for Maasai to take their cattle. Data collected shows that up to 29% of the flies carry the parasite causing sleeping sickness, but this varies by season and location. However, blood samples from cattle that graze in these areas will show how this translates into infection rates.

Tsetse flies from a wide geographic range are collected during both the dry and wet months, and then identified in the laboratory. Molecular tools are used for analysis to identify the numbers of the flies and the infection rates.

The Maasai have always known they need to move their cattle away from grazing areas for a period of time so that the grasses can recover. However, more land is being taken over by farms, and expanding populations and wildlife are increasing the competition for grazing areas. As a result, pastoralists have seen a large number of their cattle die, and their incomes reduced.

The community is a key link in both the research and the solutions. All data are presented to community groups, and potential adaptations are discussed and developed together. The goal is targeted and sustainable solutions that can be integrated into daily life long after the research is completed.

Results from the Tanzania study and 4 others that look at additional diseases impacted by climate change, like malaria, will be finalized at the end of 2016. By working with communities directly impacted by climate change, the studies will offer a new model of approaching the complicated issue that touches on land use, water, animal and human health.


For more information, contact Bernadette Ramirez.

Photo credit: WHO/TDR/ Andy Craggs

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