Malaria (Plasmodium spp.)
- Plasmodium falciparum: Highest mortality, common in sub-Saharan Africa, Southeast Asia, and South America.
- Rationale: Drug resistance (e.g., to chloroquine, mefloquine) is a major concern in this region.
- Plasmodium vivax: Widespread in Southeast Asia, often relapsing due to hypnozoites.
- Rationale: Chloroquine resistance is emerging; primaquine is needed for radical cure.
- Plasmodium knowlesi: Zoonotic, transmitted by macaques, common in Malaysia, Indonesia, and Thailand.
- Rationale: Rapid 24-hour cycle, can cause severe disease; artemisinin-based therapy is first-line.
- Soil-Transmitted Helminths (STHs)
- Ascaris lumbricoides, Trichuris trichiura, Ancylostoma duodenale, Necator americanus
- Rationale: Poor sanitation; common in rural areas; mass drug administration (albendazole, mebendazole) is key.
- Schistosomiasis (Schistosoma spp.)
- Schistosoma mekongi: Mekong River basin (Laos, Cambodia)
- Rationale: Snail intermediate hosts; chronic fibrosis is a concern.
- Foodborne Trematodes
- Opisthorchis viverrini (liver fluke): Thailand, Laos, Cambodia, Vietnam
- Rationale: Raw fish consumption; linked to cholangiocarcinoma.
- Fasciolopsis buski (giant intestinal fluke): Rural areas, poor sanitation
- Rationale: Watercress transmission; can cause intestinal obstruction.
- Lymphatic Filariasis (Wuchereria bancrofti, Brugia malayi)
- Rationale: Mosquito vectors; elimination programs (diethylcarbamazine + albendazole) ongoing.
Key Considerations for Southeast Asia:
- Drug resistance: Malaria (artemisinin resistance in the Greater Mekong Subregion).
- Zoonotic potential: Many parasites (e.g., P. knowlesi, O. viverrini) have animal reservoirs.
- Climate change: Altered vector distribution