Background
Plasmodium vivax malaria remains a major public health concern in many tropical regions, including Cambodia. One of the key challenges in controlling P vivax is its ability to form dormant liver stages called hypnozoites, which can reactivate and cause relapses weeks to months after the initial infection. Primaquine is currently the only widely available antimalarial drug effective in eliminating hypnozoites, thus preventing relapse. Most malaria-endemic countries, including Cambodia, have traditionally used a total primaquine dose of 3.5 mg/kg administered over 14 days. However, emerging evidence indicates that this dose may be insufficient to fully clear hypnozoites in tropical P vivax strains, especially in Southeast Asia. The World Health Organization (WHO) now recommends a higher total dose of 7.0 mg/kg in most endemic regions to enhance radical cure.
