Pathogenicity of hookworms. The significance of population regression for the pathogenicity of hookworms.

A method is described to estimate the reduction of the hookworm population in the host during the infection period (population regression). A formula is proposed to estimate the average worm population during the infection period, on the assumption that a decreasing hookworm population causes a decrease in daily blood loss. Daily blood loss per worm was calculated for Ancylostoma caninum: 43 microliters; for A. ceylanicum: 14 microliters for A. braziliense: 5 microliters. Accordingly hookworms cause blood loss one half to two thirds smaller than formerly assumed.