51S The public health importance of Ascaris lumbricoides

summary Numerous studies have shown that anthelminthic treatment can be effective in improving growth rates when given to malnourished children with ascariasis. Recent investigations have also indicated that Ascaris infections can affect mental processing in some school children. Poor socio-economic conditions are among the key factors linked with higher prevalences of ascariasis, as are defaecation practices, geophagia, cultural differences relating to personal and food hygiene, occupational necessity, agricultural factors, housing style, social class and gender. Chemotherapy is currently the major tool used for the strategic control of ascariasis as a short-term goal. In the long term, improvements in hygiene and sanitation are thought to aid long-term control considerably. Targeted treatment, especially when aimed at schoolchildren, has been a major focus of recent control efforts in some areas. Universal treatment reaches more people and thus decreases further aggregate morbidity, especially in nutritionally vulnerable preschool-age children. Selective treatment requires technical effort to identify heavily infected individuals; acceptance by the community may vary in less educated popu-lations when some individuals receive treatment and others do not. Child-targeted treatment may be more cost-effective than population treatment in reducing the number of disease cases and, in high transmission areas, expanding coverage of a population can be a more cost-effective strategy than increasing the frequency of treatment. Key words: Ascaris lumbricoides, child growth, cognitive performance, chemotherapy control strategies, cost effectiveness. introduction public health relevance and recent global estimates Ascaris lumbricoides is a remarkably infectious and persistent parasite that infects a quarter of the world’s population (Pawlowski & Arfaa, 1984; Crompton, 1994). It has been widely recognized that ascariasis plays a major role in the aetiology of childhood malnutrition (Crompton, 1992). Global numbers of infections have been estimated to b