In research supported by the National Institute of Allergy and Infectious Diseases (NIAID), David A. Fidock, has proved conclusively that the malaria-causing parasite "Plasmodium falciparum" became resistant to the anti-malarial drug chloroquine through mutations in a single parasite gene. Paradoxically, this gene acts as both a shield and a chink in the armor of "P. falciparum" by making the parasite less susceptible to chloroquine, but more susceptible to some other anti-malarials.

Chloroquine helped control or eliminate malaria throughout much of the world when it became widely used in the years following World War II. Chloroquine-resistant (CQR) "P. falciparum" emerged in Southeast Asia and South America in the 1950s and spread through much of Africa within two decades. Compared with chloroquine, drugs to treat CQR malaria are more expensive and cause more side effects while working less effectively. Resurgent malaria brings death and suffering to hundreds of millions and seriously impedes economic growth throughout malarious regions.

NIAID is a component of the National Institutes of Health (NIH). NIAID supports basic and applied research to prevent, diagnose, and treat infectious and immune-mediated illnesses, including HIV/AIDS and other sexually transmitted diseases, illness from potential agents of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma and allergies.