Meeting Abstract

P2.23  Friday, Jan. 4  Caloric Restriction of the Intermediate Host Increases the Infectivity of Rodentolepis microstoma Tapeworm in Their Definitive Host GRIFFING, Paulina*; KRISTAN, Deborah; California State University San Marcos; California State University San Marcos griff042@csusm.edu

Host conditions can influence susceptibility to parasites. For parasites with indirect life cycles, it is also plausible that conditions of one host may influence parasite infectivity of another host by altering some aspect of parasite morphology or physiology. It is not known if caloric restriction (CR) of an intermediate host can influence subsequent infectivity of tapeworm cysticercoids in their definitive host. Flour beetles (Tribolium confusum) were used as an intermediate host for the rodent bile duct tapeworm Rodentolepis microstoma. Adult male beetles were placed in plastic vials (n=8-10 per vial) which were subjected to a 36% CR diet or were fed ad libitum (AL) (n = 14 vials per food treatment). After 7 months, beetles were exposed to gravid R. microstoma proglottids for 24hrs to permit infection and then returned to their food intake protocol. At 15 days post-infection, the number of cysticercoids from each beetle was counted and 8 cysticercoids from 1 beetle per vial were used to infect one laboratory mouse (Mus musculus) by oral gavage (n=6 mice for CR beetles; n = 7 mice for AL beetles). Mice were dissected 15 days post-infection. Cysticercoids from CR beetles matured into more adult tapeworms than cysticercoids from AL beetles (p=0.039). After accounting for the number of worms in the mouse, tapeworms that developed from cysticercoids of CR beetles weighed 33% less than worms from AL beetles (p=0.059). CR did not affect susceptibility of beetles to R. microstoma or beetle survival. This study is the first to show that restricted calorie intake of the intermediate host can influence the ability of tapeworms to infect and grow in their definitive host.