Scientists Map Tsetse Fly Genome; Coming One Step Closer To Controlling Vector-Borne Diseases
According to the World Health Organization (WHO), vector-borne diseases are responsible for 17 percent of all global infectious diseases. Controlling them first, is a key step toward their elimination. So, after almost a decade, scientists have finally managed to sequence the genome of the tsetse fly. The fly is responsible for spreading diseases like human African trypanosomiasis - known as sleeping sickness - dengue, and malaria. Understanding the fly's genetic sequence can give scientists clues to the unique biology that makes it able to transmit diseases to all vertebrate animals, and is a crucial step toward controlling them.
Like Us on Facebook
The flies inhabit much of sub-Saharan Africa, and put an estimated 70 million people at risk of infection. The large, biting fly has highly-developed sensory organs that allow it to zero in on potential hosts, through either smell or sight.
The study was conducted by an international team of scientists from 78 research institutes across 18 countries. They analyzed the genome of the tsetse fly, honing in on almost 12,000 genes that control protein activity. By doing this, they were able to identify the specific parts of the fly's anatomy that allow it to spread the disease.
"Tsetse flies carry a potentially deadly disease and impose an enormous economic burden on countries that can least afford it by forcing farmers to rear less productive but more trypanosome-resistant cattle," said Dr. Matthew Berriman, co-senior author of the study from the Wellcome Trust Sanger Institute, in a press release. "Our study will accelerate research aimed at exploiting the unusual biology of the tsetse fly. The more we understand, the better able we are to identify weaknesses, and use them to control the tsetse fly in regions where human African trypanosomiasis is endemic."
The tsetse fly is related to the fruit fly but its genome is twice as large. They also have an unusual life cycle. Females fertilize a single egg at a time and retain the egg in their uterus. While inside, the mother secretes a substance from specialized glands that the fetal larva feeds on until it's almost fully grown - that's when it comes out.
When looking at the fly's sensory organs, the scientists found a set of proteins responsible for sight and smell, which help it with finding a host as well as a mate. The fly's attraction to blue or black colors was also traced to its photoreceptor gene rh5. Authorities have already begun implementing methods of trapping these flies by using these colors.
The researchers also analyzed the fly's salivary molecules, and found a family of genes known as tsal, which become active when feeding on blood by counteracting the host's response. "This information will be very useful to help develop new tools that could reduce or even eradicate tsetse flies," said Dr. John Reeder, director of the Special Programme for Research Training in Tropical Diseases at WHO, in the release. "African sleeping sickness is understudied, and we were very pleased to help bring together so many research groups to work collaboratively with the one shared goal in sight - the elimination of this deadly disease."
WHO lists human African trypanosomiasis as a neglected tropical disease, and since 2013, it has taken steps toward the disease's eradication.
© 2012 iScience Times All rights reserved. Do not reproduce without permission.