South Asian Journal of Parasitology

Ascariasis, caused by the giant intestinal roundworm Ascaris lumbricoides, remains one of the most prevalent helminthic infections of humankind despite decades of preventive chemotherapy and substantial gains in global sanitation. The parasite's direct, faecal–soil–oral life cycle, the extraordinary environmental resilience of its embryonated eggs, and the social and ecological determinants of transmission combine to sustain endemicity across much of sub-Saharan Africa, South and Southeast Asia, and parts of Latin America. This critical review synthesises contemporary evidence on the epidemiology, transmission dynamics, life cycle biology, global disease burden, diagnostic and therapeutic landscape, and prevention strategies relevant to A. lumbricoides infection, while paying particular attention to emerging challenges such as anthelmintic resistance, zoonotic spillover from the closely related pig parasite Ascaris suum, diagnostic insensitivity of conventional coprological methods, and the possible influence of climate change on transmission suitability. The review draws on a structured narrative synthesis of peer-reviewed literature, integrating epidemiological, parasitological, immunological, and policy-relevant evidence. Findings indicate that, although mass drug administration has reduced moderate-to-heavy intensity infections in many settings, rapid post-treatment reinfection, suboptimal efficacy of benzimidazoles against co-endemic helminths, incomplete coverage of adults and pre-school children, and the persistence of poor water, sanitation, and hygiene infrastructure continue to undermine progress towards the World Health Organization's 2030 elimination targets. Genomic and molecular epidemiological tools are beginning to clarify fine-scale transmission networks and the zoonotic potential of pig-associated ascarids, while candidate vaccines remain at an early developmental stage. We conclude that durable control of ascariasis will require integrated, context-specific strategies that combine optimised preventive chemotherapy, strengthened water and sanitation infrastructure, improved diagnostics, and sustained surveillance for drug resistance and zoonotic transmission, situated within a One Health framework.