Studies on the influence of age in the infection of caged chickens by Raillietina laticanalis and on the susceptibility to reinfection.
The aim of the experiments was to explain the high number of worms found in chickens from a poultry facility. Infections by Raillietina laticanalis were achieved in chickens kept in the laboratory. Thirty cysticercoids obtained from beetles (Dermestes ater) caught at the poultry facility were administered by pipette to each chicken. The rate of recovered worms was employed to evaluate the persistence of the infection, the influence of bird age on susceptibility to infection, and the possibility of reinfection. To verify the persistence of the infection, a group of ten chickens was infected. At each of five different intervals, two chickens were necropsied. Tapeworms were recovered up to the 46th day. To verify the influence of bird age on susceptibility to infection, three different age groups were used in the experimental design: 3-4 weeks, 6-9 weeks, and 17-20 weeks. There was no difference in susceptibility to the infections across the groups. To investigate the possibility of reinfection, a group of birds received an additional dose of cysticercoids a few days after the first doses. Another group received the second dose only after the worms had already been established. There was a significant increase in the number of recovered worms in both groups when compared with the control. The short worms found in some experiments may be due to natural destrobilization. Thus, the high number of worms found in chickens from the poultry facility could result from both infections being acquired earlier and infections acquired at the laying stage, since we demonstrated the possibility of reinfection and the long lifespan of the worm.(ABSTRACT TRUNCATED AT 250 WORDS)
Ueta
M T
MT
Department of Parasitology, Institute of Biology, UNICAMP, Campinas (SP), Brazil.
Avancini
R M
RM
D000367:Age Factors; D000818:Animals; D002590:Cestode Infections / Q000276:immunology / Q000662:veterinary*; D002645:Chickens / Q000469:parasitology*; D004198:Disease Susceptibility; D011201:Poultry Diseases / Q000276:immunology*; D012008:Recurrence