Schistosomiasis, also known as Bilharzia, is a chronic parasitic disease that affects around 200 million people worldwide, causing liver damage and potentially death.
The Ugandan initiative is the first of four national programmes to reduce the prevalence of schistosomiasis in Sub-Saharan Africa supported by the Schistosomiasis Control Initiative (SCI) from Imperial College London and funded by the Bill and Melinda Gates Foundation. In Uganda, children and adults in affected areas will receive annual treatment for a period of 5 years. The Ugandan government will then assume responsibility for schistosomiasis control.
Dr Alan Fenwick, Director of the SCI, comments: "This programme is a great example of how the developing world is able to help itself with help from the developed world. Schistosomiasis is a visible and growing problem in sub-Saharan Africa and Uganda is the first African country to grasp the nettle, and attempt to tackle this disease on a national scale."
Professor Roy Anderson from Imperial College London based at St Mary's Hospital adds: "The programmes supported by the SCI have been made possible only by a dramatic reduction in the cost of praziquantel (PZQ), the drug used to treat schistosomiasis. Since 1990, the cost of PZQ has fallen by 94%, from $1 to around 6 cents per tablet."
This is partly due to expiry of the drug patent and the availability of generic PZQ. However, lobbying of drug manufacturers by the WHO and SCI has also had an important effect. In particular, the SCI initiative, involving annual mass treatment, has in effect created a new market for PZQ in Africa and gained influence with manufacturers.
Dr Fenwick adds: "If programmes such as these are to be successful, it is vital that Africa has access to cheap, widely available drugs. Through this initiative we have actually created a much larger market for praziquantel than previously existed."
Professor Anderson adds: "Although schistosomiasis is not an acute disease, it does eventually kill those suffering from it. In the past, most of the population in Africa did not live long enough for it to cause mortality, but now that the population is living for longer it is a growing problem."
Dr Regina Rabinovich from the Bill and Melinda Gates Foundation adds: "The Bill & Melinda Gates Foundation is very pleased to help support the work of the Government of Uganda to control schistosomiasis. By creating a successful prevention and treatment program that can be emulated in countries around the world, the Schistosomiasis Control Initiative has the opportunity to make a major impact in the fight against schistosomiasis worldwide. It is our hope that this partnership with Imperial College London, the World Health Organization and the Harvard School of Public Health, will result in many lives extended, and the prevention of unnecessary suffering and disability."
Schistosomiasis
Schistosomiasis is a chronic parasitic disease caused by infection with the blood fluke (worm) Schistosoma spp. It is one of the most common parasitic diseases in the world, affecting some 200 million people and causing severe disease in approximately 20 million people. In Africa, as illnesses such as polio and tuberculosis have been controlled, schistosomiasis has emerged as a major silent killer, typically striking around the age of 35.
The parasite, which multiplies in fresh water snails, enters the human body through the skin, when people come into contact with fresh water. After entering the body, the parasite travels to the liver, where it grows to a worm about a centimeter in length. Male and female worms pair up and then live for many years in the blood vessels around the bladder and intestine, feeding off the blood. Female worms lay many eggs per day, which escape from the body back to the water during urination and defecation.
In heavy infections, thousands of eggs escape from the body daily, but in doing so rupture capillary blood vessels causing heavy blood loss. Those eggs which do not escape become trapped in the liver, causing a blockage and extreme damage, eventually leading to death.
Those most at risk of schistosomiasis are school-age children, women, and those involved in occupations such as irrigation farming and fishing.