title: Rhythmic egg release by Heligmosomoides polygyrus (= Nematospiroides dubius), parasitic Trichostrongylida of the murine gut.
abstract: Heligmosomoides polygyrus is a strongyle parasite of the murine small intestine. The existence of a daily rhythm of parasite egg production was sought. Two series of measurements were analyzed, one lasting 3 days, the other 4. Variables measured were faecal weight emitted hourly and the density of parasite eggs/h/g faecal matter. Results show a very significant rhythm of egg production, with a 12 h period and variable amplitude. A peak of excretion was recorded between 0500 and 0600 and another between 1700 and 1800, followed by a greater peak corresponding to egg release between 0000 and 0100 or 1200 and 1300. There also exists a negative influence of the phenomenon on itself: a peak of production is followed by a highly reduced excretion 6-h later. The analysis of faecal production showed the existence of a 12-h cycle and of a 24-h cycle independent of the former. As in the case of egg production, the same negative influence of faecal production on itself was observed with a 6-h delay. The peaks of faecal matter and egg excretions do not coincide but there are certain similarities between the two phenomena. Crossed correlations between the faecal production and egg production series show instantaneous relations or those with a 4-5 or 6 h delay. This is consistent with an effect of faecal production, thus intestinal transit, on egg excretion, but this remains to be confirmed by subsequent work.
mesh_terms: D000818:Animals; D005243:Feces / Q000469:parasitology; D005260:Female; D007422:Intestines / Q000469:parasitology*; D051379:Mice / Q000469:parasitology*; D008815:Mice, Inbred Strains; D010060:Ovulation; D010507:Periodicity; D013223:Statistics as Topic; D014251:Trichostrongyloidea / Q000502:physiology*