Onchocerciasis, most commonly known as river blindness, is an eye and skin infection that is predominant in sub-Saharan Africa. Blackflies live and breed on their river banks and streams, and they typically bite humans to transmit the tiny parasitic worm responsible for river blindness, Onchocerca volvulus. The worms reproduce inside the body, and their offspring migrate to the skin, where they cause intense itching and rashes, and to the eye where they cause ocular symptoms and, ultimately, blindness. A complete cure requires decades of treatment, and it can get complicated if Loa loa, another parasitic worm infection, is also involved. The World Health Organization (WHO) estimates that river blindness currently affects an approximate 18 million people worldwide. Researchers are concerned that the recent widespread use of the anti-parasitic medication ivermectin may cause the worms to eventually develop resistance to the drug.
The research initiative, The Onchocerciasis Vaccine for Africa (TOVA), was launched as a result of the London Declaration on Neglected Tropical Diseases, which called for tools to eliminate river blindness from Africa.
In the newly published research, the scientists describe sequencing the complete genome of O. volvulus worms gathered from Ecuador, Uganda and West Africa and reconstructing the genetic makeup of Wolbachia, the symbiotic bacteria that lives within the worms. The researcher identified genes that coded for common proteins and molecular reactions essential to infection. The authors noted the significance of their study towards developing potential new treatments for diseases associated with parasitic worm infections, specifically, river blindness.
The research, published this week in Nature Microbiology, was conducted in part by scientists of the National Institute of Allergy and Infectious Diseases (NIAID). Their work has revealed insights into the workings of the parasite, and they’re now working towards designing better treatments. Ideally, they're expecting to develop a preventive vaccine. So far, they've identified 16 different proteins that could be used towards developing potential new medications to combat the disease. The researchers state that their findings will support future basic and translational onchocerciasis research.
It's amazing that the genome sequencing of the worm and of its symbiotic bacteria are being utilized as a tool for the development of a vaccine. A lot can be learned about the biological makeup of a species simply by analyzing their full genome. This can allow us to see the problem from a fundamental perspective, or even to strategize a different approach. Optimistically, a successful vaccine will be developed from these studies, and it'd be awesome to see the disease fully eradicated.