This study investigated the effect of breast-feeding in protection against protozoan infection in infants with persistent diarrhea. Infants were classified into 2 groups; 161 breast-fed infants and the same number of non-breast-fed infants. Microscopic examinations of stool were done for detection of parasites and measuring the intensity of infection. Moreover, serum levels of IgE and TNF-alpha were measured by ELISA. Cryptosporidium spp., Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Blastocystis sp. were demonstrated in infants with persistent diarrhea. The percentage of protozoan infections was significantly lower in breast-fed infants than that in the non-breast-fed infants. The levels of IgE and TNF-alpha were significantly lower in the breast-fed group than in the non-breast-fed group. There were significant positive associations between the serum levels of IgE and TNF-alpha and the intensity of parasite infection in the breast-fed group. It is suggested that breast-feeding has an attenuating effect on the rate and intensity of parasite infection.
Antigens, Protozoan/analysis/*immunology ; Diarrhea, Infantile/*diagnosis/parasitology ; Entamoeba ; Entamoeba histolytica/*isolation & purification ; Entamoebiasis/*diagnosis/parasitology ; Enzyme-Linked Immunosorbent Assay ; Feces/parasitology ; Female ; Giardia lamblia ; Giardiasis/*diagnosis/parasitology ; Humans ; Infant ; Intestines/parasitology ; Protozoan Infections/*diagnosis/parasitology ; Tumor Necrosis Factor-alpha/metabolism

The alpha/beta-tubulin heterodimer is the basic subunit of microtubules in eukaryotes. Polyclonal antibodies specific to recombinant alpha-tubulin of Giardia lamblia were made, and found effective as a probe to specifically detect G. lamblia by immunofluorescence assays. Nucleotide sequences of alpha-tubulin genes were compared between G. lamblia WB and GS strains, prototypes of assemblage A and assemblage B, respectively. A set of primers was designed and used to amplify a portion of the alpha-tubulin gene from G. lamblia. PCR-RFLP analysis of this alpha-tubulin PCR product successfully differentiated G. lamblia into 2 distinct groups, assemblages A and B. The results indicate that alpha-tubulin can be used as a molecular probe to detect G. lamblia.
Animals ; Antigens, Protozoan/*genetics/immunology ; Base Sequence ; Giardia lamblia/genetics/immunology/*isolation & purification ; Giardiasis/*diagnosis/immunology/parasitology ; Humans ; Molecular Probes/genetics/immunology ; Molecular Sequence Data ; Polymerase Chain Reaction/*methods ; Polymorphism, Restriction Fragment Length ; Protozoan Proteins/*genetics/immunology ; Sequence Alignment ; Tubulin/*genetics/immunology