Research published, co-authored by staff at the development charity Sightsavers, evidences that the blinding disease onchocerciasis may be eliminated through ivermectin treatment over a sustained period. The findings show the disease may already be eliminated in one Nigerian state1 - a significant milestone on the road towards the end of this blinding neglected tropical disease (NTD) in Africa.
Globally the World Health Organization (WHO) estimates that 120 million people2 are at risk from, and 37 million3 people are already infected with, onchocerciasis (also known as river blindness), a parasitic disease transmitted by the bite of the black simulium fly which breeds in fast-flowing water.
The disease is treated by Mectizan® (ivermectin*), which is donated by global pharmaceutical company MSD, (known as Merck in the US and Canada) and distributed to individuals by NGOs such as Sightsavers.
The research confirms that ivermectin treatment can eliminate onchocerciasis infection and probably disease transmission in endemic African countries. It does this by killing the larval stage of the parasite. It is also thought that repeated treatment may affect the fertility and longevity of adult worms, increasing the feasibility of eliminating infection and transmission long-term. This enhances a study in Senegal and Mali which indicated that ivermectin taken six monthly or annually for 15 to 17 years3 could help control the disease. Both studies were supported by the African Programme for Onchocerciasis Control (APOC), Sightsavers’ key partner in fighting onchocerciasis.
Commenting on the findings, Simon Bush, Sightsavers’ Director of Neglected Tropical Diseases and an author of the research said: “Onchocerciasis needlessly devastates the lives of individuals, families and whole communities, which is why the research findings are significant not just for those living in Kaduna, but for those at risk across Africa. This research strongly suggests elimination has been achieved in two foci areas of Kaduna State. If we can start declaring areas disease-free, and help rid Africa of this parasitic disease, we would not just eliminate one of the NTDs but would reduce levels of avoidable blindness and alleviate the negative impact on economic productivity. This move to elimination will be followed in many Sightsavers-supported projects.”
The epidemiological evaluation using the skin snip parasitological diagnostic method was carried out in two onchocerciasis foci areas in Kaduna State, examining 3,703 people in 27 communities. Comparison of the findings with a 1987 Sightsavers’ baseline survey revealed that the median prevalence pre-treatment infection levels of 52 per cent were, after almost 20 years of treatment, reduced to 0 per cent. All individuals examined were skin snip negative for the prevalence of O.volvulus microfilia in the skin1.
Kaduna State is one of 32 states where onchocerciasis is a public health problem in Nigeria. The main strategy for control of the disease is by mass distribution of Mectizan® (ivermectin). To ensure the tablets reach the remote communities, Sightsavers has helped to pioneer the community-based distribution system which uses trained village volunteers to hand out the drugs at a local level. Large-scale distribution of this treatment was started by Sightsavers in Kaduna State in 1991 with support of the Ministry of Health.
The next step is an entomological evaluation of residual onchocerciasis transmission levels during a full season required by APOC to confirm if elimination can be declared and treatment in this area ceased. Sightsavers is working with APOC to support this surveillance.
Onchocerciasis is one of 17 NTDs identified by the WHO4 which are believed to affect one billion of the poorest and most vulnerable people in the world. Sightsavers maintains that treating such diseases is one way to help alleviate poverty in some of the world's poorest communities. Last month it launched its plan to invest more than £27 million over the next decade to help combat this NTD across Africa. It is also investing in programmes to support the elimination of the blinding NTD trachoma across Africa and Asia by 2020.
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This press release is reprinted by Alanna Shaikh out of an obscure sense of guilt. It does not represent the opinions of Alanna Shaikh or any of her employers.
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