Worm burden, pathophysiology and indirect nutritional effect of

Thirty-two rats infected with 500, 1 000 and 4 000 Nippostrongylus brasiliensis larvae generated different responses. Autopsies performed 48 hours post infections showed a retention of fewer worms in the lungs of moderate infections than the heavy infections. Moderate decreases in total protein were observed in sera of rats ni experiments B and D, except that the average found in experiment C was markedly lower than the control’s. The reduced levels varied from 23-37 per cent. Average diameter of muscularis externae in experiments D and E were almost twice or twofold the measurements found in experiments C and B compared with the control’s. The mean adult worm population recovered from each experiment appeared proportional to the larval dose given per infection. Infections with moderate and heavy burdens produced lower glucose figures in the serum compared with the control’s. The range of reduction was 40-68 per cent. Reduction in weight gains were more pronounced in the rats heavily infected than in the groups which were moderately inoculated. These qualitative and quantitative differences obtained in this study of light, moderate and crowed infections demonstrate that gradient and true competitions for the host’s diet by the worms existed. The decreased results collected from the biochemical tests were pathologically important and were consequently indirect results of reduced digestion and absorption rate of available food materials in the host’s intestine. The histo-pathological and physiological findings, and the poor weight gains shown by the infected rats were directly caused by the host-parasite interactions associated with the operating nutritional mechanism during the infection