Date of Award


Document Type


Degree Name

Master of Science




Twenty rats (Rattus norvegicus) received infective inocula of 5, 10, 20, and 40 third-stage larvae of Angiostrongylus cantonensis. The effects of varying doses of larvae on prepatent period larval production, worm establishment, worm size, and fertility were studied. The aquatic gastropod Biomphalaria glabratta was the experimental intermediate host.

The duration of the prepatent period varied from 37 to 45 days. The shortest prepatent period was observed in animals that received the highest infective inoculum. The prepatent period showed a significant inverse relationship with increasing inoculum size. Larval production increased logarithmically, followed by a plateau phase. The number of larvae per gram of feces (52,000 and 40,000) was highest in animals receiving infections of 20 or 40 larvae, respectively. The percentage establishment of worms in rats increased as infection levels increased. Effects of crowding on A. cantonensis were not observed in females; however, a significant positive relationship in body volume was observed for males. There was no relationship between fertility (number of larvae per gram of feces per female) and population density.

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