American Journal of Tropical Medicine and Hygiene 2003-11-01

Transmission-blocking activity of tafenoquine (WR-238605) and artelinic acid against naturally circulating strains of Plasmodium vivax in Thailand.

Narong Ponsa, Jetsumon Sattabongkot, Pattamaporn Kittayapong, Nantana Eikarat, Russell E Coleman

Index: Am. J. Trop. Med. Hyg. 69(5) , 542-7, (2003)

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Abstract

The sporontocidal activity of tafenoquine (WR-238605) and artelinic acid was determined against naturally circulating isolates of Plasmodium vivax in western Thailand. Primaquine was used as a negative control and a dihydroacridine-dione (WR-250547) was used as a positive control. Laboratory-reared Anopheles dirus mosquitoes were infected with P. vivax by allowing mosquitoes to feed on blood (placed in an artificial-membrane feeding apparatus) collected from gametocytemic volunteers reporting to local malaria clinics in Tak province, Thailand. Four days post-infection, mosquitoes were refed on uninfected mice treated 90 minutes earlier with a given drug. Drug activity was determined by assessing oocyst and sporozoite development. Neither primaquine nor artelinic acid affected oocyst or sporozoite development at a dose of 100 mg of base drug/kg of mouse body weight. In contrast, tafenoquine and WR-250547 affected sporogonic development at doses as low as 25.0 and 0.39 mg/kg, respectively. The potential role of these compounds in the prevention of malaria transmission is discussed, as are alternative strategies for the use of transmission-blocking antimalarial drugs.