Achieving success in the global fight against the "big three" diseases - HIV/AIDS, tuberculosis and malaria, which together account for 5.6 million deaths a year - may well require a concurrent attack on the world's most neglected tropical diseases, says a team of researchers in the international open access journal PLoS Medicine.
The team presented their work at a meeting on malaria and the neglected tropical diseases at the Nobel Forum, Stockholm, on 30-31 January 2006, organized by the UN Millennium Project and hosted by Karolinska Institutet and the Nobel Forum.
The neglected tropical diseases, such as leprosy and sleeping sickness, are disabling infectious diseases (mostly due to parasites) affecting the world’s poorest people. The research team - Peter Hotez (Principal Investigator, Human Hookworm Vaccine Initiative), David Molyneux and Eric Ottesen (Global Alliance to Eliminate Lymphatic Filariasis), Alan Fenwick (Schistosomiasis Control Initiative), Jeffrey Sachs (Director of the UN Millennium Project and of the Earth Institute at Columbia University) and Sonia Sachs (Millennium Village Project) - argues that initiatives for tackling the big three would be far more effective if they also included control of the neglected tropical diseases.
"The evidence indicates that coinfection with one or more neglected tropical disease may profoundly affect the outcome of one or more of the big three," says the team. For example, people with HIV infection or TB who are also infected with helminth infections, such as hookworm and schistosomiasis, have a worse prognosis. There is also emerging evidence that people infected with the neglected tropical diseases are more susceptible to becoming infected with the big three.
In addition to these interactions, it is becoming clear that there is extensive geographic overlap between the big three and the neglected tropical diseases. "HIV/AIDS, TB, and malaria occur predominantly in populations who are polyparasitized," say Professor Hotez and colleagues. The public health community, they argue, must therefore begin to integrate neglected disease control with its worldwide efforts to tackle HIV, TB, and malaria.
"The neglected tropical diseases," they say, "must now join the big three to create a 21st century 'gang of four.' For too long, the public health community has been tackling each of these diseases in isolation."
It would cost just 40 cents per person per year - a total of just US$200 million annually - to deliver a package of four drugs to about 500 million Africans, which would control or eliminate seven neglected tropical diseases. "Given the compelling logic and the very modest costs of embracing neglected tropical disease control efforts," say the authors, "it is surprising that those aiming to control the big three have largely ignored these opportunities."
In a linked Perspective article commenting on Professor Hotez and colleagues’ paper, Juerg Utzinger and Don de Savigny (Swiss Tropical Institute) say that "it makes sense to integrate interventions for multiple diseases when those interventions share a common technical approach, a common target population, and a collectively high disease burden."