# Evaluation of Malaria Parasite Transmission Competency Using a Nanozyme-Based Immunodiagnostic Targeting Female Gamete Antigen Release

## TL;DR

A new test detects malaria transmission capability by measuring a specific antigen released during parasite activation.

## Contribution

A novel nanozyme-based immunoassay was developed to detect PfG377, a marker of malaria transmission competency.

## Key findings

- PfG377 levels were higher in activated parasite cultures compared to nonactivated ones.
- PQ-treated patient samples showed significantly reduced PfG377 signals, indicating drug efficacy.
- The assay shows potential for field use in identifying transmission-competent malaria cases.

## Abstract

Preventing malaria parasite transmission to the mosquito
vector
is a key elimination challenge that could benefit from a diagnostic
test that can identify transmission-competent individuals. Only sexual
parasite forms, called gametocytes, which activate into gametes (gametogenesis)
upon mosquito uptake or blood sampling are responsible for transmission.
Herein, we devised a nanozyme-based immunoassay to detect the Plasmodium falciparum female gametocyte activation
antigen PfG377, which is released during gametogenesis.
Initial validation of our nanozyme assay with cultured parasites demonstrated
that levels of PfG377 were higher in supernatants
of activated versus nonactivated cultures and those treated with transmission
blocking drugs. To define the field potential of this approach, patient
samples from a clinical transmission-focused trial were used, including
those receiving treatment with the gametocytocidal drug primaquine
(PQ) that sterilizes gametocytes and blocks transmission. PQ-treated
patient samples showed significantly lower signals of PfG377 2 days after treatment, consistent with an inability of PQ-treated
gametocytes to activate and release antigen upon blood sampling. This
study serves as a pathfinder for field transmission rapid diagnostics
to detect transmission-competent individuals, which could help revive
malaria elimination strategies.