Sensitivity of Plasmodium vivax to chloroquine in Sa Kaeo Province, Thailand

Neglect of Plasmodium vivax malaria

“…However, sustained survey work measuring risk of CQ failure in vivax malaria has been done only in Indonesia, Thailand and India. In Thailand, a thorough examination of several thousand infections revealed almost no evidence of resistance [36][37][38][39][40]. Among 869 subjects evaluated in three separate studies in India, none showed evidence of resistance to CQ [41][42][43].…”

Chloroquine Resistance inPlasmodium vivax

“…However, Thailand represents the only one of these nations in which adequate surveys have been conducted (38,72,103): 1,046 subjects were reliably evaluated, and only 4 (0.4%) had recurrent parasitemia within 28 days after infection (and these responded to a second round of CQ therapy). No reports of CQ efficacy against P. vivax were found from Cambodia, Laos, China, or the Koreas.…”

Current Malaria Status and Distribution of Drug Resistance in East and Southeast Asia with Special Focus to Thailand

“…Since then, antimalarial drug resistant malaria has posed a major problem in malaria control. However, chloroquine is still the drug of choice for eliminating P. vivax blood stages (Congpuong et al 2002;Tasanor et al 2006).…”

“…Reverse ratio of P. vivax/P. falciparum of 60 : 40 was however reported during (Congpuong et al 2002. Such an increase in P. vivax prevalence is even more dramatic in certain geographical areas, i.e., Sa Kaeo, a province in eastern Thailand bordering Cambodia, which could be due to changes in vector potential (Limrat et al 2001).…”

“…Since the appearance of chloroquine-resistant P. falciparum strains in the 1960s, multidrug resistant P. falciparum has emerged and spread to most areas of the country (Harinasuta et al 1965;Hall et al 1975; Malikul 1 9 8 8 ; K a r b w a n g a n d H a r i n a s u t a 1 9 9 2 ; Charoenviriyaphap et al 2000). In contrast, drug resistance in P. vivax has not been reported in Thailand (Congpuong et al 2002;Tasanor et al 2006). The Southeastern border of Thailand and Cambodia has long been known as the epicenter and established multidrug resistance areas to chloroquine, sulfadoxine/pyrimethamine and diminished sensitivity to quinine Wongsrichanalai et al 2001Wongsrichanalai et al , 2002.…”