Single-Cell Transcriptomics and Development of Gametocyte-Specific Molecular Markers for Avian Malaria Parasites

Area of Science:

• * Parasitology
• * Molecular Biology
• * Ornithology

Background:

• * Avian malaria, caused by Plasmodium parasites, threatens global bird populations, especially in island ecosystems.
• * Understanding transmission is limited by a lack of molecular tools to quantify and sex parasite gametocytes.
• * Nucleated erythrocytes in birds and lack of in vitro culture hinder molecular studies.

Purpose of the Study:

• * To develop and validate the first molecular markers to differentiate asexual, male, and female gametocytes of Plasmodium relictum.
• * To enable sensitive quantification and sex determination of transmissible avian malaria stages.
• * To provide tools for improved avian malaria transmission dynamics research.

Main Methods:

• * Utilized single-cell RNA sequencing to identify conserved, stage-specific transcripts.
• * Employed orthology-guided stage mapping for marker development.
• * Validated markers for two Plasmodium relictum cyt-b lineages (pSGS1 and pDELURB4).

Main Results:

• * Developed molecular markers capable of quantifying and distinguishing male and female gametocytes.
• * Markers demonstrated higher sensitivity and earlier, longer detection than microscopy.
• * Revealed higher male-to-female gametocyte ratios compared to blood smear estimates.

Conclusions:

• * Novel molecular markers offer a sensitive method for studying avian malaria transmission.
• * These tools overcome limitations posed by avian host erythrocytes and culture systems.
• * Conserved marker sequences suggest potential applicability across diverse Plasmodium species.