Malaria, one of the world's "big three" diseases, is a major health problem. Forty percent of the world's 6.5 billion people live in areas where malaria transmission occurs. As many as three million people are diagnosed with new cases of P. vivax malaria each year, which is one of the four types of malaria. "It will be imperative for the global health community to find ways to prevent the spread of these new strains of P. vivax to the continent of Africa," says Dr. Zimmerman.

In Madagascar, malaria is endemic to more than three-quarters of the island. With almost one million clinical cases reported each year, this disease is a major public health problem. Major efforts to fight malaria are focused on Plasmodium falciparum. While P. vivax is the second most prevalent malaria parasite, public health data on it is limited. "We did not anticipate such a widespread phenomenon when we started the study with our Malagasy colleagues from the National Malaria Control Programme. Finding vivax malaria in a group previously considered resistant adds yet another public health threat to this population. It was bad news. We need to understand how the parasite has evolved in Madagascar to spread disease to a broader population," says Dr. Didier M-nard from Pasteur Institute.

Dr. Odile Mercereau-Puijalon, Head of the Parasite Molecular Immunology Unit at the Pasteur Institute, commented, "The large numbers of P. vivax parasitized red blood cells in Duffy-negative patients shows an efficient invasion process in cells considered to be resistant to infection. This capacity is clearly not restricted to a single P. vivax strain in Madagascar and is a widespread phenomenon across the island. Our findings illustrate the extraordinary capacity of malaria parasites to overcome barriers. This calls for increased vigilance in the efforts to control malaria."

With these novel findings, the Case Western Reserve and Pasteur Institute researchers will examine how the malaria parasites successfully invade the cells and determine the molecular receptor involved in this process. Through their future studies the team hopes to determine how these parasites invade red blood cells and contribute to development of an effective vaccine against vivax malaria.

Source: Case Western Reserve University