Prevalence of Giardia lamblia antibodies in serum and milk in lactating women from different social classes in Egypt.

Prevalence and levels of systemic and milk antibodies to G. lamblia in the different social classes of the population were studied using the IFAT and nor-partigen immunoglobulin plates. Blood and milk samples were collected simultaneously from lactating women in urban (Cairo) and rural (Benha) areas. Serum IgG was present in 90% of rural low standard mothers, 58% of urban moderate standard mothers, and 25% or urban high standard mothers (P less than 0.01, P less than 0.001 and P less than 0.01). Antilog of mean of antibody titers was significantly higher in the low standard rural mothers than in the urban moderate and high standard ones. Specific secretory IgA antibody in milk was found in 71% of rural low standard mothers, 31% of urban moderate standard mothers, and 16.6% of urban high standard mothers (P less than 0.001, P less than 0.01 and P greater than 0.05). The antilog of mean S-IgA titers was also higher in the low standard rural mothers. The titer levels of S-IgA in the three classes did not show any correlation with the quantitative levels of total IgA in milk, while specific IgG showed a positive correlation with the total serum IgG in the low standard rural mothers only (P less than 0.05). This study documented the widely different antibody response to G. lamblia in individuals living in different social classes.