Fecal blood loss measured with Cr51 was estimated in nine children with various degrees of infection with Trichuris trichiura. They were found to lose about 0.005 ml of blood per worm per day, about 6 to 10 times less than from Necator americanus and 30 to 50 times less than from Ancylostoma duodenale. Patients lose about 0.8 ml of blood per million eggs per day and about 0.25 ml per thousand eggs per gram of feces. The last parameter is only approximate because of the variability in the consistency of the feces.
It was estimated that infections of over 800 parasites—producing more than 5 million eggs per day—induce anemia in children.