The World Health Organisation (WHO) has published a technical brief on the control and elimination of Plasmodium vivax malaria. Owing to the particular biological characteristics of P. vivax (one of the four species responsible for malaria in humans), specific strategies are needed to combat this parasite. Several ISGlobal malaria specialists participated in the creation of this brief: Quique Bassat was a member of the Steering Committee responsible for leading the documentation effort, and Ivo Mueller and Mar Velarde were on the Writing Committee. The work was carried within the framework of ISGlobal's designation as a WHO Collaborating Centre for Malaria Control, Elimination and Eradication.
P. vivax is the most common human malaria species outside Africa. In 2013, the WHO estimated that the parasite was responsible for 16 million cases of malaria, accounting for almost half of the global burden of the disease outside Africa. Moreover, many of the countries where P. vivax predominates are closer than others to completely eliminating malaria from their territories. Strategies specifically targeting this species must therefore be developed if we are to reach the international goals set for this disease. In the words of Pedro Alonso, Director of the WHO Global Malaria Programme, "If we beat P. vivax malaria, we will not only achieve the international goal of eliminating malaria from 35 countries by 2030, we will also lay the groundwork for the future eradication of this ancient disease."
One of the challenges that make P. vivax malaria particularly difficult to control and eliminate is the fact that the mosquitoes that transmit the parasite usually bite people outdoors rather than indoors where they sleep. As a result, indoor spraying and insecticide-impregnated bed nets, the two vector control methods most often used against P. falciparum (the predominant human malaria species in Africa) are less effective against P. vivax. Furthermore, the lifecycle of P. vivax includes a dormant liver stage that is undetectable with current diagnostic methods. This characteristic gives rise to a pool of people who carry the infection but are asymptomatic and may not receive any treatment until they relapse months or even years later.
Besides providing detailed guidelines on the best strategies for vector control and the prevention, diagnosis, treatment and monitoring of P. vivax malaria, the technical brief calls upon researchers to focus on developing new tools to address the problems specific to the fight against this species. In conclusion, the report emphasises the close link between the fight against P. vivax and poverty reduction, development, and equity. While the risk of infection is higher in the most marginalized groups, these are precisely the populations that have the least access to services aimed at preventing, diagnosing and treating the disease.