Eimeria media: Selection and characterization of a precocious line

Abstract

A precocious line of Eimeria media was obtained by selection for early development of oocysts in rabbits. The prepatent period was reduced from 108 to 72 h. The precocious line was less pathogenic than the original strain, and its multiplication rate was lower. Rabbits given oocytes of the precocious line were totally immune to challenge with the original strain as assessed by change in weight gain but were partially protected as assessed by oocyst output. Selection for precocious development was accompanied by morphological changes in the sporulated oocytes; each sporocyst contained only one large refractile body instead of the two smaller bodies seen in the original strain.

Dependence of the immune response to coccidiosis on the age of rabbit suckling

“…Until recently, attenuated lines have been selected in six rabbit coccidia: E. coecicola , E. flavescens (Pakandl 2005), E. intestinalis, Eimeria magna, Eimeria media (Licois et al 1990(Licois et al , 1994, and Eimeria piriformis (Pakandl and Jelínková 2006). Thus, attenuated lines are available in all relevant species, perhaps with exception of less frequent and rather moderately pathogenic species Eimeria irresidua.…”

“…Thus, attenuated lines are available in all relevant species, perhaps with exception of less frequent and rather moderately pathogenic species Eimeria irresidua. Very effective protection against challenge with wild strains was elicited by precocious lines of E. media (Licois et al 1994) and E. magna (Drouet-Viard et al 1997). To finish development of a vaccine against rabbit coccidiosis, further testing of protective immunity induced by precocious lines, including field trials, and safety of the vaccine is needed.…”

Electron microscopic study on sporocysts and sporozoites of parental strains and precocious lines of rabbit coccidia Eimeria intestinalis , E. media and E. magna

“…In parent strains, the morphology is as usual, with a single refractile body (RB) in each sporozoite. In contrast, there is only one extremely large RB in every sporocyst in the precocious lines of E. magna and E. media (Licois et al 1994. In the precocious line of E. intestinalis, two of the four sporocysts have this appearance, i.e.…”

“…Precocious lines were derived from three species of rabbit coccidia: Eimeria intestinalis (Licois et al 1989(Licois et al , 1990, E. magna and E. media (Licois et al 1994) in the Rabbit Pathology Unit, INRA, Tours, France. These strains are characterized by a shortened prepatent period and the terminal merogonies are absent from the life cycle of E. magna (Pakandl et al 1996a) and E. media (Pakandl et al 1996b), whereas the third of four asexual generations is lacking in E. intestinalis (Licois et al 1989(Licois et al , 1992.…”

Selection of a precocious line of the rabbit coccidium Eimeria flavescens Marotel and Guilhon (1941) and characterisation of its endogenous cycle

“…Although precocious lines have been already selected in four rabbit coccidia: Eimeria coecicola, E. intestinalis, E. magna and E. media (Licois et al 1990(Licois et al , 1994, a precocious line has not yet been derived in E. flavescens, which is, next to E. intestinalis, the most pathogenic rabbit coccidium. The endogenous cycle of the original strain (OS) was already described (Pakandl et al 2003).…”