Dispersion and infectivity of Toxocara canis eggs after passage through chicken intestine

Yslla Fernanda Fitz Balo Merigueti, Ricardo da Silva Raposo, Bianca Pelegi Zampieri, Letícia Maria de Lima Cerazo, Ludimilla Pereira, Vamilton Alvares Santarém

Toxocariasis is an important, but neglected, worldwide zoonosis. It is considered a primarily soil-transmitted disease, but food-borne transmission has been associated with the consumption either of raw or undercooked meat of paratenic hosts, including birds. Despite the number of experimental studies carried out to evaluate the behavior of Toxocara spp. larvae in birds, their role in the dispersion of eggs into the environment remains unclear. Thus, this study aimed to evaluate the potential of broiler chickens to release Toxocara canis eggs into the environment, and the infectivity of eggs after passage through the intestine. Forty commercial broiler chickens, aged 60 days, were randomly distributed into three groups. Groups 1 (n = 16) and 2 (n = 16) were orally infected with 5000 embryonated and 5000 unembryonated T. canis eggs, respectively. Group 3 (n = 8) served as a control. Following infection, fecal samples from each chicken were examined using a centrifuge-sedimentation technique. At 24-h, 72-h, and 7-day post-infection (PI), four chickens each from the G1 and G2 groups, and two from the G3 group were killed. After euthanasia, the intestinal content and liver were collected for recovery of T. canis larvae. Results revealed that broiler chickens have the potential to disperse both embryonated and unembryonated T. canis eggs, following 2- to 6-h PI. In addition, the eggs shed into the feces of the G2 birds, after incubation in laboratorial conditions, were infective when they were tested in a bioassay using mice. In conclusion, broiler chickens have the potential of dispersing Toxocara spp. eggs into the environment and the eggs passed through the intestine are infective after being incubated in experimental conditions.