Parasite genotypes and host immune mediators in primary and recurrent episodes of vivax Malaria in Colombia.

[OBJECTIVES.] To identify Plasmodium vivax genotypes in the pregnant and non-pregnant population and explore their association with immune mediators.

[MATERIALS AND METHODS.] Two cohorts of patients with uncomplicated vivax malaria were followed for 120 days in Puerto Libertador and Tierralta, Cordoba, Colombia: 41 pregnant women and 46 non-pregnant individuals, all treated with standard treatment. Parasite genotypes (microsatellites Pv3.27, Pv3.502, and Pv1.501) and the expression of host immune mediators (IL-13, IL-10, TNF-alpha, IFN-gamma, IL-8, TGF-beta, Fox-P3, PD-L1) were compared between primary and recurrent infections.

[RESULTS.] The frequency of recurrences was higher in pregnant women (41.6%) than in non-pregnant individuals (8.7%). Parasite genetic diversity was higher in pregnant women, although without exclusive alleles. Recurrences were genetically homologous (same alleles) in only 23% and 33% of cases in pregnant and non-pregnant individuals, respectively. Regarding immune mediators, only Fox-P3 expression varied significantly in pregnant women, with higher expression in the primary episode than in the recurrent one.

[CONCLUSIONS.] Pregnant women are exposed to a high frequency of vivax malaria recurrences, with high parasite genetic variation, which may affect the development of effective protective immunity and favor adverse obstetric outcomes, both maternal and neonatal. These findings raise the need to strengthen and optimize prevention and treatment actions for vivax malaria during pregnancy.