Transmission-blocking activities of artesunate, chloroquine, and methylene blue on Plasmodium vivax gametocytes

is now the main cause of malaria outside Africa. The gametocytocidal effects of antimalarial drugs are important to reduce malaria transmissibility, particularly in low-transmission settings, but they are not well characterized for . The transmission-blocking effects of chloroquine, artesunate, and...

Full description

Saved in:

Bibliographic Details
Published in:	Antimicrobial agents and chemotherapy Vol. 68; no. 9; p. e0085324
Main Authors:	Chaumeau, Victor, Wasisakun, Praphan, Watson, James A, Oo, Thidar, Aryalamloed, Sarang, Sue, Mu Phang, Htoo, Gay Nay, Tha, Naw Moo, Archusuksan, Laypaw, Sawasdichai, Sunisa, Gornsawun, Gornpan, Mehra, Somya, White, Nicholas J, Nosten, François H
Format:	Journal Article
Language:	English
Published:	United States 04-09-2024
Subjects:	Animals Anopheles - drug effects Anopheles - parasitology Antimalarials - pharmacology Antimalarials - therapeutic use Artemisinins - pharmacology Artemisinins - therapeutic use Artesunate - pharmacology Artesunate - therapeutic use Chloroquine - pharmacology Chloroquine - therapeutic use Humans Malaria, Vivax - drug therapy Malaria, Vivax - parasitology Malaria, Vivax - transmission Methylene Blue - pharmacology Methylene Blue - therapeutic use Oocysts - drug effects Plasmodium vivax - drug effects Sporozoites - drug effects Plasmodium vivax transmission gametocytes Anopheles dirus antimalarials membrane-feeding assay Thailand
Online Access:	Get more information
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	is now the main cause of malaria outside Africa. The gametocytocidal effects of antimalarial drugs are important to reduce malaria transmissibility, particularly in low-transmission settings, but they are not well characterized for . The transmission-blocking effects of chloroquine, artesunate, and methylene blue on gametocytes were assessed. Blood specimens were collected from patients presenting with vivax malaria, incubated with or without the tested drugs, and then fed to mosquitos from a laboratory-adapted colony of (a major malaria vector in Southeast Asia). The effects on oocyst and sporozoite development were analyzed under a multi-level Bayesian model accounting for assay variability and the heterogeneity of mosquito infection. Artesunate and methylene blue, but not chloroquine, exhibited potent transmission-blocking effects. Gametocyte exposures to artesunate and methylene blue reduced the mean oocyst count 469-fold (95% CI: 345 to 650) and 1,438-fold (95% CI: 970 to 2,064), respectively. The corresponding estimates for the sporozoite stage were a 148-fold reduction (95% CI: 61 to 470) and a 536-fold reduction (95% CI: 246 to 1,311) in the mean counts, respectively. In contrast, high chloroquine exposures reduced the mean oocyst count only 1.40-fold (95% CI: 1.20 to 1.64) and the mean sporozoite count 1.34-fold (95% CI: 1.12 to 1.66). This suggests that patients with vivax malaria often remain infectious to anopheline mosquitos after treatment with chloroquine. Use of artemisinin combination therapies or immediate initiation of primaquine radical cure should reduce the transmissibility of infections.
ISSN:	1098-6596
DOI:	10.1128/aac.00853-24