Larval distribution in different organs of ICR strain mice infected with Toxocara canis

In this study 80 ICR mice were infected per os with 260 embryonated Toxocara canis eggs each through a stomach tube. Ten mice were sacrificed at weekly intervals over an eight-week period. Internal organs including livers, lungs, hearts, spleens, kidneys, brains, and carcasses were pooled separately and T.canis larvae from each category treated with artificial digestive fluid were recovered and later collected by the Baermann technique. Larval distributions at a given week in different organs or in a given organ at different weeks were compared and analyzed. Results revealed that total larval recovery increased from week one (11.6%) to four(19.7%); thereafter it decreased gradually and dropped to 13.4% by week eight. Larval distribution in different organs varied with time. No larvae were recovered from the heart or spleen during the study period, except for a small number recovered from the spleen in the 4th and 5th weeks after infection. In general, the larvae were recovered mainly from the brain, carcass and liver. Larval recovery from the liver was high in the first two weeks (4.5% and 3.6%, respectively) and in week 4(5.6%). Recovery from the brain increased drastically in week 4(6.8%) and remained high. Recovery from the carcass increased with time. In the case of the lungs, a sharp peak was observed in week 3(4.8%), but recovery from the kidneys was low (0.7-1.6%). Our results indicated that the ICR strain mouse is also a suitable animal model for the study of toxocariasis in paratenic hosts.