The life cycle of Nematodiroides zembrae (Nematoda, Trichostrongylina) in the rabbit.

The morphogenesis and the chronology of the life cycle of Nematodiroides zembrae (Bernard, 1965), a parasite of Oryctolagus cuniculus from Spain, were studied in detail in its natural host. For each experiment a morphological description of the different stages of the life cycle is provided. The free-living larvae developed in eggs until infective stage. First hatching began at 10 days. Twenty-one, worm-free rabbits were each infected per os with N. zembrae larvae and killed 3 days after infection (DAI) and every day from 4 to 22 DAI. By 3 DAI all recovered larvae were exsheathed and present in the small intestine. The third moult occurred between 6 and 7 DAI. The last moult occurred between 11 and 19 DAI. The prepatent period lasted for 21-22 days. The distribution of N. zembrae along the small intestine of the rabbit is described. Significantly different distributions of the parasite along the small intestine indicated that migrations occurred during the development of N. zembrae in the rabbit. The life cycle of N. zembrae is compared with the 5 known life cycles of Nematodirus spp. in ruminants. The biological data are very similar in both groups except for the prepatent period.