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

## TL;DR

The study found that pregnant women in Colombia experience more frequent and genetically diverse recurrences of vivax malaria compared to non-pregnant individuals.

## Contribution

The study identifies higher recurrence rates and parasite genetic diversity in pregnant women with vivax malaria and links this to immune mediator expression.

## Key findings

- Pregnant women had a higher recurrence rate (41.6%) compared to non-pregnant individuals (8.7%).
- Parasite genetic diversity was higher in pregnant women, but no exclusive alleles were found.
- Fox-P3 immune mediator expression was significantly higher in primary infections in pregnant women.

## Abstract

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

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.

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.

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.

Identificar los genotipos de Plasmodium vivax en población gestante, y no gestante y explorar su asociación con mediadores inmunes.

Se siguieron durante 120 días dos cohortes de pacientes con malaria vivax no complicada en Puerto Libertador y Tierralta, Córdoba, Colombia: 41 gestantes y 46 no gestantes, todas tratadas con el tratamiento estándar. Se compararon los genotipos parasitarios (microsatélites Pv3.27, Pv3.502 y Pv1.501) y la expresión de mediadores inmunes del hospedero (IL-13, IL-10, TNF-alfa, IFN-gamma, IL-8, TGF-beta, Fox-P3, PD-L1) entre infecciones primarias y recurrentes.

La frecuencia de recurrencias fue mayor en gestantes (41,6%), que en no gestantes (8,7%). La diversidad genética parasitaria fue mayor en gestantes, aunque sin alelos exclusivos. Las recurrencias fueron genéticamente homólogas (mismos alelos) solo en 23% y 33% de los casos en gestante y no gestantes, respectivamente. En cuanto a los mediadores inmunes, solo la expresión de Fox-P3 varió significativamente en gestantes, con mayor expresión en el episodio primario que en el recurrente.

Las mujeres embarazadas están expuestas a una alta frecuencia de recurrencias de malaria vivax, con alta variación genética del parásito, lo que puede afectar el desarrollo de inmunidad protectora efectiva y favorecer desenlaces obstétricos adversos, tanto maternos como neonatales. Estos hallazgos plantean la necesidad de fortalecer y optimizar las acciones de prevención y tratamiento de la malaria vivax durante la gestación.