Faecal egg counts and expulsion dynamics of the whipworm, Trichuris trichiura following self-infection

Abstract

More than 400 million humans are estimated to be infected with the intestinal helminth parasite, Trichuris trichiura. The infection is chronic in nature and high-intensity infection can lead to colitis, anaemia, Trichuris Dysentery Syndrome and reduced cognitive performance. Single doses of 400 mg albendazole or 500 mg mebendazole (MBZ) are used in mass drug administration programmes, but this has been shown to be insufficient. In this study, worm expulsion dynamics are described after MBZ treatment, given as a multi-dose and single-dose treatment in two separate T. trichiura self-infection studies. Worm expulsion dynamics post-treatment showed a similar pattern regardless of the dose regime, with the first worms observed on day 2 and the last worms expelled on days 9 and 13 post-treatment. Establishment of a chronic infection was observed following the inefficient single-dose treatment. The prepatent period was 13-16 weeks in both studies and worms were found to have a lifespan of at least 1 year and 10 months. These self-infection studies provide key information on the chronicity of T. trichiura infections, expulsion dynamics after anthelmintic treatment and the prepatent period, as well as the fecundity of female worms, which was around 18,000 eggs/female per day.