This year on World Health Day -- Monday, April 7 -- the World Health Organization (WHO) is emphasizing the prevention and control of vector-borne diseases. Vector-borne diseases mostly refer to malaria and other neglected tropical diseases that are transmitted by mosquitoes, sandflies, and other insects, as well as schistosomiasis, which is transmitted by snails.
These vector-borne diseases are some of the most common diseases on our planet and most of them disproportionately affect people living in extreme poverty. The link to poverty reflects the fact that poor people often live in low-quality housing without window screens or air conditioning and are exposed more frequently to the bites of insects. They also live in areas of environmental degradation where vectors flourish.
Almost one billion people each year are infected with a vector-borne tropical disease, and according to new information based on a recently released study, more than 1.2 million people die every year from vector-borne diseases. To put this number in perspective, the number of people who die annually from vector-borne diseases is almost as high as those who die from HIV/AIDS.
Among those most vulnerable to vector-borne tropical infections are people who live in conflict zones such as in Syria or Sudan where they acquire leishmaniasis transmitted by sandflies. Over the last few decades, leishmaniasis has killed or disfigured hundreds of thousands of people in these war-torn areas.
Vector-borne diseases can also strike the poor living in tropical and substropical areas of wealthy countries including the southern United States. At our Houston-based National School of Tropical Medicine at Baylor College of Medicine, our faculty have found high rates of transmission of several tropical infections including dengue fever and West Nile virus infection, and are on the hunt for Chikungunya virus in Houston and our region.
The global health community has a huge task ahead in order to control or eliminate the worst neglected tropical diseases transmitted by insects or snails. Insecticidal spraying and other vector-control measures have gone a long way, for example, to eliminate Chagas disease transmission in Brazil and adjacent areas of the southern cone of South America. In addition, through vector control and use of insecticide treated nets and other measures, malaria has been controlled or even eliminated in several countries in the Middle East, North Africa, and Central Asia, while in sub-Saharan Africa, use of insecticide treated nets is reducing the mortality of this disease substantially.
Ultimately, the control and elimination of vector-borne disease will likely require the development of new technologies including a new generation of vaccines. Through Gates Foundation support, a new malaria vaccine has been developed by the pharmaceutical company GSK, and several pharmaceutical companies are competing to develop the first vaccine for dengue fever.
For other vector-borne NTDs such as Chagas disease, leishmaniasis, and schistosomiasis there is no traditional commercial market for investing in new vaccines because these diseases exclusively affect the poorest of the poor. Accordingly, several non-profit product development partnerships are working to develop vaccines to combat these orphaned NTDs, including our Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development .
The WHO is recommending we use this World Health Day to remember the devastating impact of vector-borne diseases, especially on the world's poor. The good news is that there is cause for optimism that through new technologies we might one day dramatically improve global health through disease control and elimination.
Peter Hotez is president of the Sabin Vaccine Institute, Texas Children's Hospital Endowed Chair in Tropical Pediatrics, and dean of the National School of Tropical Medicine at Baylor College of Medicine. He is also Baker Fellow in Disease and Poverty at Rice University.