Migratory Behavior of Toxocara canis Lavae in the Brain of Mice with Special Reference to Distribution

The present study was undertaken to get further information on the migratory gehavior of Toxocara canis larvae in the central nervous system in eperimentally infected mice. Mice were infected with approximately 500 of infective eggs of T.canins. According to the schedule, mice, 5 males and 5 females, were sacrificed at 2,3,5,7,14,21,28 and 56 days after injection and the brain tissue was extracted from each mouse and devided into six parts ; cerebrum, cerebellum, medulla oblongata, olfactory bulb, potuitary and spinal cord. Number of the larvae was counted qualitatively and quantitatively. The results are summarized as follows : 1. Total recovery rate(in average) of the larvae in the brain at the various intervals gradually inceased from 0.4% to 10.6% with the highest rate on the 28th day of post-infection. 2. Total recoery rates(in average) of the larvae obtained throughout the study were 54.2% in male and 45.8% in female, out of 504 larvae. 3. Distribution rates of the larvae were revealed as high as 57.5% in cerebrum and 32.5% in cerebellum, and 4.4% in medulla oblongata, 2.8% in spinal cord, 2.0% in olfactory bulb and 1.6% in pituitary in decreasing order. 4. Number of the larvae per mg of wet weight of the brain found was 0.06 in cerebrum and cerebellum, 0.03 in olfactory bulb and pituitary, 0.02 in medulla oblongata and 0.01 in spinal cord, respectively.