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Recommendations for Enhancing P. vivax Research (2002)

Approximately 100 participants from 25 countries attending the conference "P. vivax Research: 2002 and Beyond" February 3-8 met in small groups on the final day to draft recommendations to specifically enhance P. vivax research in the areas of pathology and morbidity; immunity, antigens and vaccines; drug treatment, resistance and development; epidemiology and transmission; and the P. vivax genome. Participants included researchers from P. vivax endemic areas and representatives from malaria research and control funding organizations.

Several research needs were identified by multiple groups suggesting their fundamental importance to enhance all P. vivax research:

  • Analysis presented from many endemic regions showed that P. vivax infections are significantly underdiagnosed microscopically. Inexpensive, rapid and accurate P. vivax specific diagnostic tools capable of detection of low parasitemias in mixed malaria infections would contribute to both research and control efforts.
  • Basic research and intervention assessment would be greatly enhanced by improved in vitro culture and cryopreservation methods for all P. vivax life cycle stages and host cells and better utilization of available primate models.
  • P. vivax specific standardized reagents (molecular markers, recombinant antigens, monoclonal antibodies, etc.) need to be made widely available.
  • The paucity of basic knowledge about some of the unique biological characteristics of the P. vivax parasite, such as relapse, reticulocyte infection and early gametocytemia, needs to be addressed in order to serve as a foundation for the development of new drugs, vaccines and other interventions.
  • Increased collaboration between endemic area and non-endemic area scientists and training a new generation of P. vivax researchers is critical to sustained, productive P. vivax research.
  • Unique public health interventions and strategies are needed to control P. vivax malaria.

Pathology and morbidity research

  • Clinical epidemiological studies in different transmission settings are needed to measure the spectrum and magnitude of P. vivax disease manifestations and immunity with specific attention to the contributions of relapsing infections and emerging drug resistance.
  • Research on the human and parasite molecular mechanisms involved in P. vivax associated pathology and morbidity, especially related to fever, anemia and pregnancy is needed.
  • Interactions during P. vivax and P. falciparum co-infections (i.e. cross-protection and pathophysiology) should be examined.
  • The socioeconomic burden of P. vivax acute and chronic disease needs to be defined in order to advocate for greater focus on its control.

Immunity, antigen and vaccine research

  • The global goal of a combined P. vivax-P. falciparum combined vaccine needs to be strongly established based on the fact that in most malaria endemic regions of the world, including parts of Africa, P. vivax transmission co-exists with P. falciparum transmission.
  • P. vivax vaccine candidate antigen discovery and development pipeline that does not necessarily depend on the lead of P. falciparum vaccine research is needed.
  • Studies of natural P. vivax diversity, immunity and markers of protection using standardized reagents.
  • Extensive discussion and analysis of how and where to test P. vivax vaccines alone and/or in combination with P. falciparum vaccines is required.

Drug treatment, resistance and development research

  • Methods to assess drug susceptibility in vitro and in vivo need to be improved and standardized.
  • The epidemiology and mechanisms of P. vivax chloroquine and primaquine resistance need to be examined.
  • Clinical trials of safety and efficacy of shorter courses of high dose primaquine treatment are needed to replace current ineffective lower dose and long regimens.
  • Simple, rapid and inexpensive G6PG deficiency assays are needed for use in conjunction with primaquine treatment decisions.
  • Curative, anti-P. vivax liver stage drug discovery research should be significantly increased.

Epidemiology and transmission research

  • Epidemiological understanding of P. vivax transmission would be greatly enhanced by analysis of personal infection risk factors and mapping small and large geographic scale risk factors over time.
  • Studies of the impact of human movement on P. vivax transmission are needed.
  • The need for widely and systematically gathering of P. vivax epidemiological data in standardized, shared databases was recognized.
  • Research on P. vivax interactions with vector mosquitoes and the dynamics of transmission are needed.

Genetic diversity and genomic studies

  • A number of reagents were identified as of paramount importance for genomic and genetic diversity studies (P. vivax genomic DNA, stage specific cDNA libraries, pulse field gel chromosome blots, genomic DNA libraries of major mosquito vectors).
  • Training and training resources in bioinformatics and epidemiological analysis methods are needed.
  • Due to the lack of parasite material, requirements for good quality DNA sequence data and supportive documentation deposited in public databases are needed.
  • It was suggested that a network or consortium be formed of those researchers in developed and developing countries interested in P. vivax diversity and population genetics studies.