Schistosoma mansoni oviposition in vitro reflects worm fecundity in vivo: individual-, parasite age- and host-dependent variations.
In an attempt to determine whether in vitro oviposition of adult S. mansoni reflects the fecundity status of worms in vivo, Mongolian gerbils and ICR, BALB/c and SCID mice were infected with about 100 cercariae and examined on an individual basis, 5-12 weeks later, for worm burden, counts of eggs in liver and small intestine, and for the rate of egg deposition of ex-vivo female worms cultured in vitro, singly or in pairs, over a 3-5 day incubation period. The percentage of egg-laying female worms and the number of eggs laid/female after 3 days in culture showed, like worm fecundity in vivo, wide inter-worm variability, especially in 5-, 6- and 12-week-old worms; varied significantly with the age of the parasite with a maximum level attained by worms of approximately 8 weeks of age; and differed in worms recovered from different host species and strains. The data taken together indicate that measuring the egg-producing ability of S. mansoni in vitro reflects the fecundity status of worms in vivo and additionally provides likely explanations for hitherto poorly understood findings on schistosome fecundity.
el Ridi
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R
Department of Parasitology, Hirosaki University School of Medicine, Aomori, Japan.
Ozaki
T
T
Inaba
T
T
Ito
M
M
Kamiya
H
H
D000818:Animals; D005260:Female; D005298:Fertility; D005849:Gerbillinae; D006790:Host-Parasite Interactions; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D016513:Mice, SCID; D010058:Oviposition; D012550:Schistosoma mansoni / Q000502:physiology*; D012555:Schistosomiasis mansoni / Q000469:parasitology*