Assessment of malaria-induced anaemia and parasite cytoadhesion phenomenon on Plasmodium vivax pathogenesis and transmission

• Grant number: 13/05613-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2013
• End date: May 31, 2015
• Field of knowledge: Biological Sciences - Parasitology - Protozoology of Parasites
• Principal Investigator: Fabio Trindade Maranhão Costa
• Grantee: Omaira Vera Lizcano
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Plasmodium vivax is responsible for almost 90% of malaria in Brazil. Although anaemia is the most common complication of vivax malaria, its pathogenesis is still poorly understood. Despite malaria patients with gametocytes had lower hemoglobin concentrations in comparison patients without gametocytes, there are no yet studies to confirm the impact of anaemia on gametocytogenesis. However, it is believed that rosette formation (adhesion of P. vivax-infected to uninfected erythrocytes) might be one of the mechanisms responsible for anaemia. In fact, recently it has been shown that red blood cells parasitized by asexual forms of Pv are able to cytoadhere to different receptors in the host. Moreover, preliminary data obtained by our group showed that Pv sexual forms could also adhere to the dermal microvasculature. Thus, we believe that these factors may contribute to increase the efficiency of parasite transmission during the mosquito meal, and mosquito's saliva components could lead to de-sequestration of gametocytes. This proposal aims to: (1) verify the impact of anaemia due to vivax malaria on gametocytes production; (2) determine the gametocytes ability to adhere to the dermal microvasculature cells; (3) evaluate whether Pv asexual forms are capable of rosetting and its association with anaemia; (4) evaluate the relationship of the previous factors on infectivity in the mosquito vector. The study will be carried out by performing ex vivo functional with Pv gametocytes and asexual forms harvested from patients diagnosed with vivax malaria attended at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, a referral center for the study of tropical diseases located in the Amazonas state (endemic area for vivax malaria).