River blindness has been banished from key areas of Nigeria where it was once endemic, bringing the disease one step closer to being eliminated.

Nigeria’s ministry of health has announced that more than 4.2 million people have been freed from the threat of the disease in Plateau, Nasarawa and Kaduna states.

According to the ministry of health, surveys show that the transmission of river blindness has now been interrupted. No new cases of the disease have been found in the region, and there is now no evidence of the parasite in the black flies that spread it.

While there are still challenges to be faced before it is confirmed that the disease has been eliminated, this achievement means the infection is no longer being spread in these areas and that treatment can be stopped.

Globally, river blindness is a problem in 37 countries, with more than 205 million people at risk of infection. About a quarter of them – some 50 million people – live in Nigeria. Kaduna was one of the first areas to treat river blindness in the 1980s because it was one of the worst hit. The state previously made headlines at the end of 2017 when seven-year-old Dorcas received the billionth treatment for neglected tropical diseases, delivered by Sightsavers and its partners in Kaduna.

Sightsavers Nigeria country director Sunday Isiyaku said: “Kaduna was one of the most endemic areas in the most endemic country in the world. If we can remove river blindness here, we should be able to remove it anywhere.

“When we first started working in Kaduna there were so many people suffering. Just over 20 years later, we couldn’t find one single case. Just think if we can make that happen everywhere.”