THE HOST-PARASITE RELATIONSHIPS IN PYRIDOXINE (VITAMIN-B6) DEFICIENT COTTON RATS INFECTED WITH LITOMOSOIDES-CARINII (NEMATODA, FILAROIDEA)

This paper demonstrates that the establishment and growth of the filar ial nematode parasite, Litomosoides carinii, is reduced in pyridoxine- deficient cotton rats. Young cotton rats were assigned to one of three dietary groups: vitamin B6-deficient cotton rats (B6-AL) were fed a p yridoxine-free diet ad libitum; pair-fed controls (B6+PF) were fed the same amount of pyridoxine-free diet as animals in the deficient group and given daily oral supplements of 100 mu g pyridoxine; and pyridoxi ne-sufficient controls (B6+AL) were fed the pyridoxine-free diet ad li bitum and supplemented daily with 100 mu g pyridoxine. Half of each gr oup was infected with 50 L(3) of L. carinii by subcutaneous injection 8 weeks after the start of the experimental feeding period. B6-deficie nt cotton rats ate less (P < 0.001) and gained less weight (P < 0.001) than B6-supplemented controls. The levels of microfilaraemia in defic ient animals, measured weekly throughout the experiment by taking bloo d smears, was significantly lower than in supplemented animals (P < 0. 001). The deficient rats became latent for L. carinii at 20 weeks post -infection, whereas there was patent microfilaraemia in rats in the ot her dietary groups until the end of the experiment. Smaller (P < 0.001 ) and fewer (P < 0.05) adult worms were recovered from the pleural and abdominal cavities of deficient animals than from either pair-fed or sufficient controls at autopsy 28 weeks post-infection.