EFFECTS OF PROTEIN-MALNUTRITION ON EXPERIMENTAL GIARDIASIS IN THE MONGOLIAN GERBIL

To determine the effects of protein malnutrition on the severity and d uration of infection with Giardia lamblia. Mongolian gerbils were pair -fed a pelleted control (C) dict (20% protein) and a low-protein (5%; LP) diet for 3 weeks before and after being infected with 100,000 cyst s orally. Weight loss, fecal fat, enteropooling, and the duration of c yst excretion were all greater in the infected LP than in the infected C animals. During peak infection the upper intestinal intraepithelial lymphocyte infiltration, crypt enlargement, and villus enterocyte mig ration were greater in C than in LP animals, as was the villus mast ce ll number at the end of the infection. It is concluded that in the pro tein-malnourished host the increased severity of Giardia infection cor relates with a reduction in enterocyte production and migration. proba bly secondary to a reduced lymphocyte infiltration, and the increased infection duration correlates with blunted mast cell migration into af fected villi.