The World Health Organization (WHO) has announced that Colombia has become the world’s first country to eliminate river blindness. The achievement was made possible through the mass drug administration of anti-parasitic drug Mectizan (ivermectin) in affected parts of the South American nation, combined with a sustained health education campaign in local communities.
River blindness, also known as onchocerciasis, is caused when the roundworm Onchocerca volvulus is spread to humans by the bite of an infected black fly common in river areas. The parasite causes eye damage that can lead to skin disease and blindness. According to the WHO the disease is the second-leading infectious cause of blindness worldwide. It affects more than 18 million people across the world and has made 300,000 people blind.
On-going surveillance is now being encouraged in Colombia to ensure that predictions for the criteria for elimination are correct and there won’t be an unexpected resurgence, which is always going to be a risk when the black fly vectors and the risk of re-introduction of the disease remain.
Experts say river blindness is also set to be eliminated soon in Ecuador, Guatemala, and Mexico. All three countries halted drug treatment in 2012 and began the three-year post treatment surveillance process required by the WHO to verify elimination of the disease.
The major burden of river blindness (99%) however remains in Africa. Although similar strategies are working well in some African countries, others remain with significant barriers to overcome. This includes most of Central Africa where co-infection with another parasite, Loa loa, risks a severe adverse reaction to treatment. There is also the risk that the parasites may evolve resistance to ivermectin and there are some early warning signs that this may be happening. It is therefore important to sustain research and development of new drugs and control strategies to ensure the important success in Columbia can be enjoyed by people in Africa who remain afflicted by river blindness.
LSTM is leading drug discovery and development research against human filariasis – the parasitic worm infection which causes river blindness. The Anti-Wolbachia Consortium (A·WOL), led by LSTM’s Professor Mark Taylor, is targeting the symbiotic Wolbachia bacteria. Using combinations of existing drugs, A·WOL may be able to reduce the treatment time from weeks to days and in doing so bring forward the elimination of river blindness. Another A·WOL research programme is selecting a likely new drug candidate to progress to clinical trials. Its aim is to develop an effective new alternative use in mass drug administration that will tackle river blindness in large parts of Africa and South America.
In a response to these latest developments, Professor Taylor said: “The elimination of river blindness in Colombia is an important example of how partnerships between the pharmaceutical industry, academia and global health organisations can deliver a real impact on tackling the Neglected Tropical Diseases.”