Acta Veterinaria 22. (1972)
1. szám - MOSSALAM, I. - ATALLAH, O. A. - HOSNEY, Z.: Experimental studies on visceral larva migrans of Toxocara canis in laboratory animals
Acta Veterinaria Academiae Scientiarum Hungaricae, Tomus 22 (1), pp. 71—80 (1972) EXPERIMENTAL STUDIES ON VISCERAL LARVA MIGRANS OF TOXOCARA CANIS IN LABORATORY ANIMALS By I. MoSSALAM, 0. A. AtALLAH and Z. HoSNEY Pathology and Parasitology Department, Faculty of Veterinary Medicine, Cairo Universitv, U.A.R. (Received August 20, 1971) The term larva migrans refers in common use to the migration either of canine hookworm larvae in the human skin — cutaneous larva migrans, or of canine ascarides in the viscera — visceral larva migrans (Beaver et al., 1952). The latter condition occurs mainly among children under four years of age and is usually acquired by the ingestion of soil contaminated with faeces of infected dogs. After being swallowed the infective eggs hatch in the intestine, and the second stage larvae penetrate the intestinal wall to reach the liver. The majority of the larvae remain in the liver, but some pass on to the lungs and other organs. The histological changes in the liver of mice infected with T. canis were first described by Hoeppli et al. (1949). Done et al. (1960) found larvae of T. canis in the liver, brain, lungs and muscles of experimentally infected pigs, while Schaeffler (1960) recovered them from the liver, muscles and other tissues of sheep. Bisseru (1969) reported on the lesions caused by larvae of T. canis in the liver, lungs and brain of mice. The histopathological changes in the various host species have not been fully described, however. The present investigation was therefore undertaken to get more information about the tissue reaction caused by migrating larvae of T. canis in different organs of some laboratory animals and chickens. Material and methods Eggs of T. canis were obtained from the distal portion of the uterus by dissecting fresh adult female worms. They were cultivated in 0.5% formalin at 28—30 °C for four weeks. Prior to inoculation, the eggs were washed several times with tap water, and their number was estimated. Eight individuals each of 30-day-old mice, rats, guinea-pigs and 11-day-old chickens were experimentally infected with about 2000 embryonated eggs except the mice which received about 500 eggs. The eggs were introduced into the esophagus with the aid of a dropper. Two animals from each group were killed by cutting their throats 10, 20, 30 and 40 days after infection. Fresh samples taken from the lungs, kidneys, liver and brain were fixed in 10% formalin, embedded in paraffin, serially cut, and the sections stained with hematoxylin and eosin. Acta Veterinaria Academiae Scientiarum Hungaricae 22, 1972