SUMMARY Kinetics of gut lymphocyte subpopulations were studied in normal and malnourished groups of mice infected with Giardia lamblia. The maximum parasite load was observed at second, third, and first week of postinfection in normal controls, moderate (8%) and severe (30/?) protein deficient groups respectively. The number of G lamblia trophozoite in 3% protein deficient group was low compared with control groups. A significant increase in T cell population of intraepithelial lymphocytes and lamina propria in normal and moderate protein deficient groups was observed with the development of infection. It was less marked, however, in the severely malnourished group. Interplay of mucosal immune status with nutrition and G lamblia infection is discussed.Infection with Giardia lamblia in man sometimes results in diarrhoea and malabsorption.i Histopathological abnormalities2 such as mild villous atrophy with mononuclear cell infiltration and decrease in the villous crypt ratio in small intestine have been reported. The infection is more severe in malnourished3 or hypogammaglobulenaemic children.' Wright et al reported that the degree of malabsorption is dependent on the intraepithelial lymphocyte counts. They did not, however, study the nutritional status of these subjects. Protein deficiency is known to increase the risk of infection5 probably through its deleterious effect on the host's humoral and cellular responses.6 Ganguly et a17 reported no change in the splenic T lymphocytes but an increase in B lymphocytes in a mouse model established for G lamblia infection.8 The recovery from G lamblia infection correlated with the splenic T cell number in thymectomised mice. Increased intraepithelial lymphocyte counts in the mice infected with G muris have been reported.9 As lymphocytes in G lamblia infection have been both linked with immunity and pathogenesis, there is need to examine the mucosal immune status in normal and immunosuppressed giardia infected mice.

The effect of malnutrition on the uptake of nutrients was studied in Swiss albino mice infected with Giardia lamblia. The moderate deficiency (8 % protein-deficient diet) was observed to enhance the uptake of nutrients like glucose and alanine, whereas in severely malnourished (3% protein-deficient diet) animals the uptake was significantly decreased (p < 0.001). G. lamblia infection in mice decreased the uptake of nutrients and this recovered slightly with the recovery of infection. The combined effect of moderate protein deficiency and infection lowered the enhanced uptake observed in moderately malnourished animals to a significant level (p < 0.001). In severely malnourished animals, infection with G. lamblia showed further deleterious effects on the uptake of nutrients.