Metabolic end products of helminths: their degradation and excretion by the host. Biochemical approach to the diagnosis of ascaridiasis and other helminthiases.

Accumulation, degradation and excretion by the host of helminth metabolic end products, such as branched-chain volatile fatty acids are poorly studied although they play an appreciable role in host-parasite interactions and, being detectable in excreta, provide a reliable diagnostic test for at least some helminthiases. The amount and the structure of the end products of intestinal Nematoda metabolism depend on pH, rH, pCO2, and composition of the media. In the human intestine Ascaris excretes 40-60 mmol volatile fatty acids/100 g wet weight daily, alpha-methylbutyric, alpha-methylvaleric and isovaleric acids are slowly degraded. In concentrations of 10(-3)--10(-4) M they exert an inhibitory effect on O2 consumption, oxydative phosphorylation and Mg2+-ATPase activity in mitochondria. Given by mouth to laboratory animals or injected intraperitoneally, 14C-labeled branched-chain volatile fatty acids rapidly appear in saliva and urine and are detectable by chromatography and IR spectrography.