Decoding the DNA of the tsetse fly could save millions of lives
Genetic research opens promising new doors
The infamous tsetse fly’s days may be numbered. In a multi-million dollar effort spanning several years and nations, researchers have sequenced the genetic code of one of Africa’s most reviled and dangerous pests.
“Decoding the tsetse fly’s DNA is a major scientific breakthrough that opens the way for more effective control of trypanosomiasis, which is good news for millions of herders and farmers in sub-Saharan Africa,” said Kostas Bourtzis of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture.
An end to deadly sleeping sickness
Trypanosomiasis, better known as sleeping sickness, poses a significant threat to the welfare of rural Africans. Although sleeping sickness is curable with medication, it can be fatal if left untreated. According to the Center for Disease Control, about 10,000 new cases of sleeping sickness—all caused by the tsetse fly—are reported to the World Health organization each year, though it is believed that many cases go undiagnosed and unreported. John Reeder, who leads the World Health Organisation’s (WHO) programme for research into tropical diseases suggests that “many of the affected populations live in remote areas with limited access to adequate health services, which complicates the surveillance and therefore the diagnosis and treatment of cases.”
In addition to causing physical sickness and possible death among humans, the disease borne by the tsetse fly threatens the livelihood of rural African farmers as it infects their livestock. A single tsetse bite can lead to infertility, weight loss, and a reduction in milk production in animals, often rendering them too weak for productive ploughing or transport, and eviscerating the farmers’ source of food and income.
Until now, very few options have been available to combat the deadly parasite, which has developed sophisticated means to evade mammals’ immune systems. Moreover, as Reeder notes, “detection and treatment of trypanosomiasis is expensive, difficult and dangerous for the livestock, as it often involves toxic drugs.”
The hope is that cracking the genetic code will deliver valuable insight into the nature of the tsetse fly, and perhaps into its achilles heel. Reeder is optimistic that “this new knowledge will accelerate research on tsetse control methods and help scientists develop new and complementary strategies to reduce the use of costly drugs and insecticides.”
Learning from Aedes aegypti and dengue?
Genetic intervention may also raise the opportunity for more extreme interventions. As Michael Specter in The New Yorker explains, Aedes aegypti mosquitoes are among the deadliest creatures on earth, transmitting dengue, one of the most rapidly spreading viral diseases in the world. Oxitec, a British biotechnology company, is developing a genetic modification of the host mosquitoes with the hope of stemming the tide of dengue.
The idea, Specter explains, is to “modify the genetic structure of the male Aedes mosquito, essentially transforming it into a mutant capable of destroying its own species.” Could a similar strategy work for the tsetse fly? It is not known at this stage, though it is clear that a better understanding of the tsetse’s genetics is the right place to start.
