# Genomic surveillance of malaria parasites in an indigenous community in the Peruvian Amazon

## TL;DR

This study examines malaria parasite transmission in a remote indigenous community in the Peruvian Amazon, finding high transmission rates and genetic differences that suggest imported infections.

## Contribution

The study provides genomic insights into malaria transmission dynamics and drug resistance in a remote, high-mobility indigenous community.

## Key findings

- Persistent Plasmodium vivax transmission was observed with high detection rates over the study period.
- Plasmodium falciparum parasites showed low genetic diversity and a distinct cluster linked to an outbreak.
- Common drug resistance markers and high rates of pfhrp2/3 gene deletions were detected in P. falciparum.

## Abstract

Hard-to-reach communities represent Peru’s main challenge for malaria elimination, but information about transmission in these areas is scarce. Here, we assessed Plasmodium vivax (Pv) and P. falciparum (Pf) transmission dynamics, resistance markers, and Pf hrp2/3 deletions in Nueva Jerusalén (NJ), a remote, indigenous community in the Peruvian Amazon with high population mobility.

We collected samples from November 2019 to May 2020 by active (ACD) and passive case detection (PCD) in NJ. Parasites were identified with microscopy and PCR. Then, we analyzed a representative set of positive-PCR samples (Pv = 68, Pf = 58) using highly-multiplexed deep sequencing assays (AmpliSeq) and compared NJ parasites with ones from other remote Peruvian areas using population genetics indexes.

The ACD intervention did not reduce malaria cases in the short term, and persistent malaria transmission was observed (at least one Pv infection was detected in 96% of the study days).

In Nueva Jerusalen, the Pv population had modest genetic diversity (He = 0.27). Pf population had lower diversity (He = 0.08) and presented temporal clustering, one of these clusters linked to an outbreak in February 2020. Moreover, Pv and Pf parasites from NJ exhibited variable levels of differentiation (Pv Fst = –0.52 & Pf Fst = 0.11–0.58) with parasites from other remote areas.

No artemisin resistance mutations but chloroquine (57%) and sulfadoxine-pyrimethamine (35–67%) were detected in NJ’s Pf parasites. Moreover, pfhrp2/3 gene deletions were common (32–50% of parasites with one or both genes deleted).

The persistent Pv transmission and the detection of a Pf outbreak with parasites genetically distinct from the local ones highlight the need for tailored interventions focusing on mobility patterns and imported infections in remote areas to eliminate malaria in the Peruvian Amazon.