Editor's note: This is part one of a two-part series on neglected tropical diseases. Part two will run in Friday's issue.
If necessity were the only mother of invention, there would be no neglected tropical diseases.
There are 2.7 billion people worldwide infected with the group of 13 bacterial and parasitic infections that are collectively known as neglected tropical diseases (NTD). (See list of diseases, p. 4.) "In the aggregate, they are as important as AIDS or malaria," in terms of both the health and the economic havoc they wreak, Peter Hotez, chairman of the department of microbiology and tropical medicine at George Washington University, told BioWorld Today.
But for medical innovation to address those diseases, good science needs to meet a financially viable way to bring eventual products to the people who need them.
There currently is plenty of research done on the scientific side of that equation for neglected tropical diseases; one researcher told BioWorld Today that it is currently something of a "Golden Age" for the study of parasitic diseases. Tools and technologies have allowed the sequencing of many parasites, and the technology to generate transgenic parasites is up and running, which has allowed new types of studies in the biology of the pathogens and also of their host-parasite interactions.
But neither the obvious need nor the high-quality research translates easily into therapeutics, in part due to the lack of a viable market for the for-profit sector.
Part of the reason is the poverty of those affected: neglected tropical diseases affect the rural poor in the developing world - people who by and large live on less than $2 a day, Hotez said. There may be close to 3 billion of them, but "they don't have two nickels to rub together," he added.
Even currently available off-patent drugs to treat the NTDs are unaffordable to those who need them, as would be the yet-to-be-developed recombinant vaccines necessary to prevent re-infection with some of the parasitic NTDs.
Nevertheless, there is optimism that longstanding, persistent industry concerns about investment returns can be overcome. It's happening with malaria, which also primarily affects those who lack purchasing power, and together with HIV and tuberculosis, is one of the "Big Three" diseases that primarily affect the poor of the developing world, but have nevertheless managed to become a priority for Western efforts to treat and prevent them.
There are economic reasons that the Big Three receive more attention than the neglected tropical diseases. But Hotez also attributes their disproportionate share of the attention to several documents published around 2000 which caused a "big paradigm shift." He specifically mentioned the United Nations' Millennium Development Goals, which were published in 2000. According to the Millennium Project's web site, these are "the world's time-bound and quantified targets for addressing extreme poverty in its many dimensions." The Millennium goals stress that health is not just a health problem, but an economic problem as well.
In fact, funding for the Big Three, compared to the death and disability they cause, is roughly 100 times that for the neglected tropical diseases together, despite the fact that "a body of evidence exists indicating that the control of neglected tropical diseases would greatly reduce the morbidity and mortality of malaria and reduce the transmission of HIV/AIDS," according to the Global Network for Neglected Tropical Diseases Control's website.
Hotez said the goal of those working on NTDs is to raise awareness of the enormous burden they pose for developing countries, both in and of themselves and by aiding and abetting the Big Three. Fighting NTDs would be a highly effective strategy to fight the Big Three and the misery and poverty they cause, he said, adding that the Millennium Development Goals will not be met without tackling NTDs as well as the Big Three.
"It's not the Big Three," he said. "It's the Gang of Four."