Parenteral infection in mice with Baylisascaris transfuga (Nematoda: Ascaridae) infective eggs.

In order to investigate the ability of infective larvae of the nematode Baylisascaris transfuga (Rudolphi, 1819) Sprent, 1968 to hatch from the egg-shells and then to migrate in tissues, parenteral infections of mice with embryonated eggs were performed. Two groups of outbred albino mice were infected with approximately 3500 B. transfuga infective eggs subcutaneously (s.c.) or intraperitoneally (i.p.). B. transfuga larvae in the i.p. group rapidly hatched and migrated to the intestine, liver, lungs, brain and carcass. Subcutaneous inoculation of eggs was followed also by migration of hatched larvae in the examined organs. In the s.c. mice, extensive encapsulating reactions involving the subcutaneous tissues and carcass, and containing large numbers of hatched eggs and free motile larvae, were found at the sites of inoculation. Some differences in the migratory behaviour were observed between the two groups. It is shown that B. transfuga infective larvae are able to hatch and migrate in tissues of mice, and tend to settle and/or to be trapped in the intestinal wall and muscles, even after parenteral inoculations of embryonated eggs. These results could provide basic data for further investigations on the migratory pathways of B. transfuga larvae or to perform immunological and therapeutical studies.

Visceral larva migrans in mice experimentally infected with Baylisascaris transfuga (Ascarididae: Nematoda).

Laboratory bred albino mice, weighing 20 to 25 g, were orally infected with 2000 Baylisascaris transfuga infective eggs each. Mice were randomly chosen and sacrificed on days 1, 2, 3, 10, 15, 24 and 70 post-infection. Samples of intestine, mesenteric lymph nodes, liver, lungs, heart, spleen, kidneys, uterus, brain and skeletal muscles were collected and processed for conventional histopathology. In the early infection the major necropsy findings were focal haemorrhages on the intestinal wall, liver, lungs and brain. Histologically, larvae were found in haemorrhagic areas. In the subacute-chronic infection white nodules were scattered through all the examined organs, except the brain. Histologically, the white nodules corresponded to granulomas containing larvae surrounded by lymphocytes, eosinophil leukocytes and macrophages. The migration of B. transfuga larvae in spleen, kidneys and uterus of infected mice appears to have not been reported by previous workers. The possible role of B. transfuga larvae in the Visceral Larva Migrans syndrome is discussed.