Elimination of blinding disease in sight for Nigeria

* Any views expressed in this article are those of the author and not of Thomson Reuters Foundation.

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. 

Ends/

1. Impact of long-term treatment of onchocerciasis with ivermectin in Kaduna State, Nigeria: first evidence in the operational area of the African Programme for Onchocerciasis Control, February 2012. Authored by: Afework H Tekle, Elizabeth Elhassan, Sunday Isiyaku, Uche V. Amazigo, Simon Bush, Mounkaila Noma, Simon Cousens, Adenike Abiose and Jan H. Remme  http://www.parasitesandvectors.com/content/5/1/28/abstract
2. Yaounde Declaration on Onchocerciasis Control in Africa. (2006); A Declaration of African Ministers of Health on the future of onchocerciasis in Africa and report of the meeting
3. Senegal & Mali Studies, Diawara et al, 2009- http://www.who.int/mediacentre/news/releases/2009/river_blindness_20090721/en/
4. Accelerating work to overcome the global impact of neglected tropical diseases: A roadmap for implementation, WHO, 2012

http://whqlibdoc.who.int/hq/2012/WHO_HTM_NTD_2012.1_eng.pdf

*'Mectizan'® (ivermectin) is not licensed for use in the UK.

For interviews with Simon Bush please contact the Sightsavers media team on 01444 446754, press@sightsavers.org.  For media enquiries out of hours, call 07775 928253. Further press information, including case studies, pictures and factsheets regarding river blindness and the NTDs, are also available.

Notes to editors/

About Sightsavers:

1. Sightsavers is a registered UK charity (Registered charity numbers 207544 and SC038110) that works in more than 30 developing countries to prevent blindness, restore sight and advocate for social inclusion and equal rights for people who are blind and visually impaired.  www.sightsavers.org
2. There are 39 million blind people in the world; 80% of all blindness can be prevented or cured.
3. In the six decades since its foundation, Sightsavers has:

-       Treated over 206.8 million people for blinding and potentially blinding conditions

-       Carried out over 7.1 million operations to restore sight

-       Trained almost 0.5 million primary eye care workers

-       Carried out rehabilitation training to 91,000 people

About onchocerciasis:

1. Onchocerciasis (river blindness) is a parasitic disease transmitted by the bite of the black simulium fly which breeds in fast-flowing water
   1. It is endemic in 37 countries, 30 of which are in Africa and account for more than 99 per cent of cases.  37 million people are infected³.  Over 300,000 people have already gone blind.
   2. In addition to blindness, river blindness creates nodules on the skin and severe itching, this results in damage to the pigment and over time the skin becomes mottled.
   3. In onchocerciasis endemic areas social implications include children missing out on education as they act as full-time carers for older relatives who have become blind.  People also flee areas of fertile land, closest to the river with high levels of infection.
   4. Evidence from the African Programme for Onchocerciasis Control (APOC), has found that 'Mectizan'® (ivermectin)* taken six monthly or annually for 15 to 17 years³ can help control the disease. It does this by killing the larval stage of the parasite (the medicine does not kill the adult worm, which continues to produce larvae after mating).
   5. Sightsavers’ founder Sir John Wilson first noted the devastating effects of the disease when he visited Ghana in 1947, and coined the name "river blindness" to describe it. 
   6. Sightsavers is the leading NGO supporting onchocerciasis in Africa – working in 13 countries (Nigeria, Cameroon, Sierra Leone, Liberia, Uganda, Tanzania, Malawi, Ghana, Togo, Benin, Mali, Guinea and Guinea Bissau)
   7. It costs Sightsavers as little as 5p per person to distribute 'Mectizan'® to communities using trained local volunteers.