The Plasmodium vivax genome provides new routes and challenges in the global fight against malaria

Institutions from around the world join forces in the Global Fight Against Malaria. While most research into controlling malaria has focused on the parasite Plasmodium falciparum, which is responsible for the most virulent form of the disease, there are other parasites of the same genus which, despite producing a milder form of malaria, are gaining notoriety. This is the case of Plasmodium vivax, to which is attributed almost 300 million cases of malaria each year, severe forms of the disease and resistance to some drugs. In its next issue, the journal Nature publishes a study, led by The Institute for Genomic Research (TIGR), in which it presents, for the first time, the genetic code of P vivax and draws some conclusions about the biology of this parasite and how to combat it in the future. Dr. Hernando del Portillo and Dr. Carmen Fernandez-Becerra, the only authors from a Spanish centre, have led the effort to understand and combat P vivax for many years - first from Brazil and now from the Barcelona Centre for Research on International Health (CRESIB), directed by Dr. Pedro Alonso, who is also the head of the International Health Service at Hospital Clínic of Barcelona and Chair of Public Health at the University of Barcelona. The researchers from this centre have contributed their experience in studying the virulence of the parasite in order to validate and analyse the data obtained in the sequencing carried out by the TIGR. They were pioneers in this field when they discovered the largest family of genes controlling the virulence of this parasite in a study also published in Nature in 2001. The principal author of the study is Dr. Jane M. Carlton, Associate Professor of the Department of Medical Parasitology of the New York University Medical Center, and formerly of TIGR. The main institution funding the study was the National Institute of Allergy and Infectious Diseases (National Institutes of Health), together with other funding institutions such as the Burroughs Wellcome Fund, the US Department of Defense and the National Institute of General Medical Science (National Institutes of Health).

The P vivax genome has turned out to be far more similar to that of P falciparum than was expected. The study published in Nature identifies only 150 genes specific to P vivax. Another important result of the research refers to the routes of infection of the parasite, as analysis of the genome indicates that P vivax should have alternative mechanisms for infecting the erythrocytes - the human blood cells in which the parasite resides and multiplies during its complex life cycle. These alternative routes of infection have not been observed in previous research and we now know that the genetic information necessary for this to happen is written in the genome. The scientific community must find the way to make use of these findings to fight the malaria.

Although P vivax has rarely been fatal, an increasing number of published work shows that this is not a benign parasite, since it causes severe disease and even death - something that had previously only been attributed to malaria caused by P falciparum. Furthermore, the larger public health problem in controlling P vivax lies in the fact that this parasite can reside in the liver in latent form and, months or years later, when the primary infection has been overcome, can cause clinical relapses. P vivax therefore has serious consequences for the health and economy of the countries in which it occurs, such as Papua New Guinea, India and Brazil. Despite this fact and despite the 300 million cases it causes each year, there has been a tendency to underestimate the importance of research into this form of malaria. For this reason, the authors of the study published in Nature are arguing for research into P vivax to be included in the funding schedules of the countries leading the global fight against malaria. There are still many questions to be answered and political will is as important as scientific effort in the fight against this disease. The CRESIB represents a clear example of joint effort and its commitment to research into P vivax is firm; it has created a strong group, led by Dr. del Portillo, ICREA Professor (Institució Catalana de Recerca i Estudis Avançats) who, from CRESIB and with the support of the Cellex Foundation and Dr. Alonso, pushed for the creation of an international consortium against malaria caused by P vivax and, with Dr. Clara Menendez, gained the support of the European Union to carry out a multicentre study on malaria due to P vivax and pregnancy.

Source: IDIBAPS - Institut d'Investigacions Biomèdiques August Pi i Sunyer