| How the stink of a waterbuck could prevent sleeping sickness in Kenya|
|The tsetse fly, found in 37 countries in sub-Saharan Africa, can be a curse for smallholder farmers and their families. The flies carry the trypanosome parasite that can cause sleeping sickness in humans and nagana in livestock. But a group of scientists in Nairobi is developing a powerful insect repellent using the stench of waterbucks, a type of large antelope.|
About two-thirds of Africa's population depend on small-scale agriculture, many of whom are livestock farmers. For these farmers, tsetse flies are a serious threat to economic development and food security. The economic loss in Africa's cattle production as a result of nagana is an estimated $4bn (£2.5bn) each year, according to the Stamp out sleeping sickness campaign.
With funding from the European Commission, ICIPE (International Centre for Insect Physiology and Ecology), a pan-African research organisation that investigates tropical insect science for development, has produced groundbreaking collars for livestock that contain the waterbuck smell, which tsetse flies do not like.
"Every year we lose three million cows because of the disease; 60 million cows are also affected. The flies are one of the main reasons why 80% of the land in Africa is tilled by hand – simply because we don't have enough animal power," says Dr Rajinder Saini, head of ICIPE's animal health division and principal scientist. "Fewer livestock also leads to less manure that could be used as organic fertiliser, which leads to lower yields of crop and fodder plant.
"Our approach has been to look at the ecology, biology and behaviour of the fly in detail, to look at the interaction between the parasite and the host, trying to develop a simple technology that farmers can use themselves instead of the top-down approach where everybody is dependent on foreign aid."
ICIPE is carrying out a two-year trial with farmers in Mombasa. They are 16 months into the trial, which includes 15,000 cows and 300 pastoralists.
"The first solution we came up with was NGU traps, which attract and trap the flies," says Saini. "But while working with the Masai, we found they needed more of a mobile technology; traps are stuck in the ground, these people move with their animal, so we started thinking of repellents. We looked at repellent from two different sources: synthetic sources and from animals that the fly does not like to feed upon, such as waterbucks."
ICIPE scientists studied why these animals are not attacked and have isolated powerful fly repellents from waterbuck skin, which reduce tsetse bites by up to 90%.
"Waterbucks stink; lions leave them alone because of the smell and flies leave them alone because of the sweat. We identified the pertinent odour of waterbucks and brought it down to a handful of chemical components that are responsible for keeping the flies at bay. We put the chemical into a dispenser tube that can be tied into the neck of a cow," says Professor Christian Borgemeister, director general at ICIPE. "The collar puts a coat of a waterbuck over a cow; as the herd moves along, the flies sense the cow as a waterbuck and stay away."
For the farmers in the trial, just outside of the Shimba Hills game reserve in Mombasa, the collars are a big hit. Farmers can graze their animals early in the morning and late in the evening when flies are most active, and no longer need to light fires to keep away the flies.
"One of my farms is near the national park where there are a lot of flies. A lot of my animals were infected. I might have been forced to sell my farm and move, but these collars have helped me a lot. Right now, they are free. After the trial ends we have been told they could be sold for 400 Kenyan shillings ($3, £1.90), but even if they sell them for 5,000 shillings, I am happy to pay for them because they work," says Joshua Wambua.
Another farmer, Jhapat Mwongela, says the collars have not only increased the productivity of his animals but improved his family's quality of life. "I am now able to plant different things – cassava, corn, sweet potatoes – which require the land to be tilled quite a bit. Because my cows were not sick this year, I have made significant profit. I am able to pay for my children's school and medical fees. Even their diet has been diversified because whatever I am not growing, I can now afford to buy."
Pharmaceutical companies have been slow in developing drugs to tackle diseases carried by tsetse flies because of the perception that it is not a profitable market. According to Saini, most of the drugs in the market are 60-70 years old, and humans and cattle are becoming resistant.
As a not-for-profit organisation, ICIPE hopes that producing collars on a larger scale would makeprices even lower, meaning the technology would be available to a higher number of beneficiaries. However, as this is beyond their scope of work they are seeking public-private partnerships to develop the technology.
Borgemeister is not surprised by farmers' willingness to pay for the collars. He urges pharmaceutical companies to reassess their outlook and recognise a viable market in developing drugs and technology to tackle tsetse flies.
"At the end of the day, farmers buy drugs. If this is your only source of livelihood, you're going to spare [cut back] even from your food [budget] to make this [sick] cow better. Billions of dollars are lost in the African livestock industry due to trypanosomiasis ever year; there is a market for a superior technology if we can provide it at a competitive price."