Morbidity and mortality due to ascariasis: re-estimation and sensitivity analysis of global numbers at risk

This paper presents estimates of the global numbers of people at risk from morbidity related to infection with Ascaris lumbricoides and the numbers of deaths from this infection. Morbidity is classified into 4 types: deficits in growth and fitness which are contemporaneous with infection, or permanent, overt acute illness of mild to moderate severity, and complications involving hospitalization. The estimation of morbidity is based on theoretical models of parasite distributions developed in previous papers. A sensitivity analysis is carried out in which parameters of the model are varied using a Latin hypercube sampling technique. The results estimate approximately 1300 million infections globally with 59 million at risk of some morbidity. The estimate for acute illness is 12 million cases per year with approximately 10,000 deaths. Most morbidity is in children. Sensitivity analysis suggests that infection estimates will not vary greatly with changes in parameter values but that morbidity estimates may be highly variable.