Last Updated: 17/03/2025
Evaluation of humoral immune response against Plasmodium vivax antigens in patients with malaria relapses
Objectives
*Original title in Portuguese: Avaliação da resposta imune humoral contra antígenos de Plasmodium vivax em pacientes com recaídas de malária
This project intends to characterize the dynamics of the antibody response against blood antigens of P. vivax in individuals with vivax malaria admitted to the Fundação de Medicina Tropical (Manaus-AM) who presented, or did not present, recurrences of malaria over a 90-day follow-up. The antibody response against P. vivax blood antigens (AMA-1, MSP1-19 and CSP vk210) will be determined by conventional ELISA serology in plasma samples collected during follow-up and correlated with clinical, demographic, epidemiological and parasitological data of patients admitted to the cohort, including parasite biomass through quantification of pLDH.
Plasmodium vivax is the most prevalent species that causes human malaria outside of Africa, and its biology poses a challenge for eradicating the disease. Among the characteristics of this species is its ability to cause recurrences, which correspond to the reappearance of clinical signs and peripheral parasitemia weeks to months after diagnosis and treatment of the initial infection. Recurrences can have several causes, among which the most prominent is the reactivation of latent hepatic forms of the parasite, the hypnozoites, which is called relapse. In the context of disease control and elimination, the identification of individuals carrying hypnozoites, which occur silently and are undetectable by conventional diagnostic methods, is crucial for controlling this disease. Approximately 250 patients have been recruited to date, with a recurrence frequency of 19.7%, occurring between 31-90 days after admission to the study. However, as a genuine reference for relapses, we will also analyze samples from individuals who presented recurrences outside the malaria endemic area admitted to FIOCRUZ-RJ. The results obtained in this study will be useful to identify a biomarker signature capable of detecting individuals at high risk of presenting relapse episodes, which can be used in epidemiological surveillance and as a guiding tool for intervention.
May 2024 — Apr 2025
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