Longevity of Toxocara cati larvae and pathology in tissues of experimentally infected chickens

Abstract

This study was conducted to determine the distribution patterns and duration of stay of Toxocara cati larvae in organs of chickens and to investigate chronic phase and potential zoonotic risk of toxocariasis in chickens. Chickens were orally infected with 1,000 embryonated T. cati eggs and necropsied 240 days post-infection. Organs of the chickens were examined at gross and microscopic levels; tissues were digested to recover larvae. Peribronchiolitis with infiltration of lymphocytes, and hyperplasia of bronchiolar associated lymphatic tissues (BALT) and goblet cells, were evident in the lungs of infected chickens. There were mild hemorrhages and infiltration of lymphocytes and a few eosinophils in the meninges. Larvae were recovered from 30% of the exposed chickens. Larvae recovery indicated that T. cati larvae stay alive for at least 240 days in the chicken brain. Therefore, chickens may potentially act as a paratenic host in nature and transfer T. cati larvae to other hosts.

Keywords: Toxocara cati; chicken; pathology.

Fig. 1

Peribronchiolitis, hyperplasia of the bronchiolar associated lymphatic tissues (white arrow) and goblet cells (black arrow) in the parenchyma of the lungs from a chicken infected with 1,000 Toxocara cati eggs on day 240 PI. H-E stain. Scale bar = 135 µm).

Fig. 2

Congestion (arrow) and infiltration of lymphocytes (arrow head) in the meninges of the brain from a chicken infected with 1,000 T. cati eggs on day 240 PI. H-E stain. Scale bar = 175 µm).