Plagiorchis noblei (Plagiorchiidae) in Aedes aegypti: Parasite Acquisition and Host Mortality in Trickle Infections

Abstract

The prevalence and intensity of experimental infections of Aedes aegypti with the digenean Plagiorchis noblei increased significantly with the level of trickle exposure to cercariae. Daily exposure to doses of 16 cercariae/day yielded a mean infection intensity of 13.0 metacercariae; doses of 1 cercaria/day resulted in only 2.4 metacercariae per infected mosquito larva. The prevalence of infection rose from 46% at an exposure of 1 cercaria/day to 99% at 16 cercariae/day. Host mortality rose concomitantly from 25% to 88%. Host mortality and parasite acquisition were independent of environmental temperatures (21-29 C), despite the fact that developmental times, and consequently the number of daily exposures, were more than 50% greater at the low end of the temperature scale. This may be attributable to low activity of mosquito larvae and the resulting decrease in the number of encounters with cercariae.

Experimental Infection of Radix Natalensis and Culiseta Longiareolata Larvae With Plagiorchiid Xiphidiocercariae in Egypt

“…Haematoloechus, Plagiorchis and Prosthogonimus xiphidiocercariae could successfully encyst in mosquito larvae such as Aedes aegypti, Ae albopictus, Anopheles quadrimaculatus and Culex quinquefasciatus. These entomophilic cercariae could be also considered as an efficient mean of biological control for mosquito larvae (Rao et al, 1985;Webber et al, 1987;Dempster and Rau, 1991;Lacy and Orr, 1994;Carvalho et al, 2001). Infection by encysted xiphidiocercariae could have an influence on the usual larval development of these mosquitoes.…”