DAVID H MOLYNEUX, of the Lymphatic Filariasis Support Centre, Liverpool School of Tropical Medicine, UK, tells VIBHA VARSHNEY that public health policy should focus on neglected diseases, for they are easy to control:
Are some diseases more neglected?
Some good examples of neglected diseases are Chagas' disease, Guinea worm, leprosy, lymphatic filariasis and onchocerciasis. These affect a large number of people in poor and developing countries. They are "neglected" because the donor agencies from the developed world have limited interest in them. Unfortunately, with more emphasis being on the big three killer diseases such as aids, tb and malaria and emerging and re-emerging diseases like Ebola, West Nile virus and Nipah virus, less donor money is available for the neglected diseases. After all, global funds are made up of donor money and are cash limited. If more money is given to one, less money is going to be available for the other.
Why focus on neglected diseases?
If money were spent on areas where success is more likely and not where success is less likely, millions more people would benefit and much disablement would be prevented. These neglected diseases are easy to control: the public health imperative here is simply to stop transmission. This is far cheaper and also in accordance with public health principles.
By ignoring these diseases, policy makers are forgetting scientific and operational evidence that interventions against "other diseases" are very effective. Many of the world's poorest people remain afflicted or are at risk from this group of diseases, though they need not be. By concentrating on so few agents, current policies perpetuate inequity, disrupt health finance policies, divert human resources from achievable goals, and deny opportunities for impoverished health systems to improve. Investing in neglected diseases would also strengthen the health system. Funds should be provided for both broad health sector support and disease-specific interventions.
By doing this, is success in controlling neglected diseases assured?
There are sufficient examples to prove that this works. Lymphatic filariasis has been removed from China, Chagas' disease from five South American countries; onchocerciasis from West African countries and Guinea worm from India and Pakistan. Neglected diseases are easier to control as they are transmitted by stable pathogens, which do not mutate easily. It is cost-effective, the estimated annual rates of return on investment being in the order of 14 to 30 per cent. For example, onchocerciasis control in West Africa has been described by the World Bank as one of the most effective investments in any development sector. Likewise, each us $1 invested in control of Chagas' disease in Brazil, and lymphatic filariasis in China, has produced returns of us $716 and us $15, respectively.
The problem is that influential policy makers do not promote these successes. We know that using Albendazole to control hookworm infections in Senegal could reduce the incidence of malaria by 10 times. But when we talk about malaria control, nobody even mentions it. Impregnated bed nets have effects not only on malaria but also on other vectors, such as those transmitting the pathogens causing leishmaniasis, lymphatic filariasis, Chagas' disease, and tick-borne relapsing fever.
We do not know how to treat or control "the big three". Doesn't this justify more emphasis on them?
Diseases like aids, tb and malaria are spread by pathogens that are biologically unstable and show rapid evolution of drug resistance. If the governments and researchers want to focus on the big three diseases, they will have to ensure that they produce new drugs faster than the rate at which the organisms develop resistance. Health systems cannot match this speed.
Take the case of malaria, associated with rapid development of resistance by both parasites and vectors. This challenge presented by the biology of malaria is yet to be fully appreciated or overcome -- in stark contrast with the experiences of many neglected diseases, where the biology of the organisms causing the diseases often helps health systems achieve their aims. Tackling malaria requires constantly changing tactics and policies. The costs involved in policy change are themselves substantial, and policies often cannot be implemented because of the role of the private sector in the provision of antimalarials.
What should be done?
To efficiently benefit from the substantial resources needed to reduce morbidity and mortality associated with hiv/aids, tuberculosis and malaria, a small investment should be made in the proven, cost-effective interventions against "other diseases". This could be from the Global Fund resources and would achieve broader public health goals. It would bring sustainable public-health benefits, integrate with and strengthen the health system, reduce disabling conditions and bring collateral benefits to the health of the poorest nations. The Millennium Development Goals would not be achieved if neglected diseases were not taken care of.
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