Determinants of symptomatic giardiasis in childhood.

Giardia has been frequently implicated as a causative agent for acute as well as chronic diarrheal diseases in children. The present study was aimed at exploring the determinants of manifestations of Giardiasis in childhood, in relation to various host and parasite related factors. A total of 200 children with acute (100), chronic (50) or without (50) diarrhea in last 15 days were recruited for the study and evaluated with regards to nutritional status, serum immunoglobulins, secretory IgA levels, presence of Giardia in stool/duodenal aspirate/duodenal biopsy specimen and for associated infections. Lysates from acute giardiasis cases were further studied for zymodeme (banding) pattern. After correlation of all investigations, humoral immune defect in the host was found to be the major determinant of whether the Giardial infestation would be symptomatic or not, while associated bacterial infections and zymodeme patterns were not found to be important in determining the pathogenicity or presentation of giardiasis.

Assessment of the immune and nutritional status of the host in childhood diarrhoea due to cryptosporidium.

Cryptosporidium oocysts were detected microscopically in the concentrated faecal smears (stained by modified kinyoun's acid fast stain) in 13 out of 100 (13 per cent) cases of acute diarrhoea (AD < 2 weeks duration), 7 out of 50 (14 per cent) cases of chronic diarrhoea (CD > 2 weeks duration) and none in 50 age matched controls. The grades of malnutrition of the cases and controls were calculated by the weight for age criteria and the immune status assessed by the levels of serum immunoglobulins and SIgA in duodenal fluids. Malnutrition was observed in 6 out of 13 cases (46.1 per cent) in acute and 6 out of 7 cases (85.71 per cent) in chronic cryptosporidial diarrhoeas. There was no significant statistical difference (P > 0.05) in serum immunoglobulins and SIgA levels in chronic cryptosporidiosis. SIgA was significantly reduced (P > 0.05) in cases of acute cryptosporidiosis. Cryptosporidium is an important cause of symptomatic infection in apparently immunocompetent children not having been detected in a single non-diarrhoeal control. Further a low SIgA could contribute to acute symptomatic cryptosporidiosis by favouring colonization with the parasite.