Plasmodium vivax resistance to chloroquine in Dawei, southern Myanmar

Abstract

Summaryobjective To assess the efficacy of chloroquine in the treatment of Plasmodium vivax malaria in in Dawei District, southern Myanmar.methods Enrolled patients at Sonsinphya clinic >6 months of age were assessed clinically and parasitologically every week for 28 days. To differentiate new infections from recrudescence, we genotyped pre-and post-treatment parasitaemia. Blood chloroquine was measured to confirm resistant strains.results Between December 2002 and April 2003, 2661 patients were screened, of whom 252 were included and 235 analysed. Thirty-four per cent (95% CI: 28.1-40.6) of patients had recurrent parasitaemia and were considered treatment failures. 59.4% of these recurrences were with a different parasite strain. Two (0.8%) patients with recurrences on day 14 had chloroquine concentrations above the threshold of 100 ng ⁄ ml and were considered infected with chloroquine resistant parasites. 21% of failures occurred during the first 3 weeks of follow-up: early recurrence and median levels of blood chloroquine comparable to those of controls suggested P. vivax resistance.conclusions Plasmodium vivax resistance to chloroquine seems to be emerging in Dawei, near the Thai-Burmese border. While chloroquine remains the first-line drug for P. vivax infections in this area of Myanmar, regular monitoring is needed to detect further development of parasite resistance.

Amplification of pfmdr1 , pfcrt , pvmdr1 , and K13 Propeller Polymorphisms Associated with Plasmodium falciparum and Plasmodium vivax Isolates from the China-Myanmar Border

“…Resistance to common antimalarial drugs has been reported for P. vivax in the GMS, including Myanmar and Vietnam, and also in Indonesia (38)(39)(40). A trend for a gradual decline in the in vitro sensitivity of this parasite to CQ had also been reported during 2005 to 2008 around the China-Myanmar border and in central China (41,42).…”

Efficacy of Dihydroartemisinin-Piperaquine for Treatment of Uncomplicated Plasmodium falciparum and Plasmodium vivax in Cambodia, 2008 to 2010

“…Although high treatment failure rates indicate reduced susceptibility, CQ resistance can only be confirmed when failure occurs with a CQ blood concentration of Ն100 ng/ml (30). CQ resistance has also been reported in Myanmar and Thailand (31,32). Since the treatment failure rates were observed to be Ͼ10% in two of the study sites (Preah Vihear and Ratanakiri), a new treatment policy is needed.…”

Resistance to Therapies for Infection by Plasmodium vivax

“…Accepting that the data provide at best a rough sketch of risk by geographic zone, it seems clear that eastern Indonesia represents the most advanced resistance problem, with a Ͻ50% probability of therapeutic success apparently being the norm (12,14,15,180,210,211 (95,167,219). A number of reliable studies involving large numbers of patients in both Thailand (59,125,136,217,229) and India have shown almost uniform susceptibility to chloroquine in vivax malaria (154,226), although very recent work from the Gujarat State in western India found a 91% success rate among 65 evaluated patients (209).…”