Specific IgG and IgA Antibody Reactivities in Sera of Children by Enzyme-Linked Immunoassay and Comparison With Giardia duodenalis Diagnosis in Feces.

BACKGROUND: Giardia duodenalis is conventionally diagnosed in fecal samples using parasitological methods. However, sensitivity is poor when only a single sample is analyzed, due to intermittent excretion of cysts in feces. Alternatively, the serum antibodies to G. duodenalis can be used for parasite diagnosis and epidemiological studies to determine previous exposure. We compared the rate of G. duodenalis infection between serum anti-Giardia IgG and IgA antibodies and fecal examination in Brazilian children. METHODS: Fecal and serum samples were tested from 287 children at a clinical laboratory and from 187 children at daycare centers. Fecal samples were processed using conventional parasitological methods and coproantigen detection for Giardia diagnosis. Serum samples were tested using an in-house ELISA for detection of anti-Giardia IgG and IgA. RESULTS: G. duodenalis was found in 8.2% (N=39) of the 474 children analyzed. The sensitivity and specificity of ELISA were 80.0% and 90.0% for IgG and 80.0% and 83.3% for IgA, respectively. The total positivity rate of anti-Giardia IgG and IgA in the sera was 13.9% (N=66) and 23.6% (N=112). The agreement between the positivity of specific antibodies and the detection of G. duodenalis in feces was moderate for ELISA-IgG, kappa index (95% CI)=0.543 (0.422-0.664), and mild for ELISA-IgA, kappa index (95% CI)=0.283 (0.162-0.404). Among the children infected with other enteroparasites, 11.6% (N=10) and 24.4% (N=21) showed reactivity to anti-Giardia IgG and to IgA, respectively. This cross-reactivity was more frequent in samples from children infected with Endolimax nana and Entamoeba coli. CONCLUSIONS: The higher frequency of specific antibody reactivity compared with G. duodenalis diagnosis in feces could reflect continuous exposure of children to G. duodenalis infection, resulting in long-lasting immunological memory and/or cross-reactivity with other intestinal amoebas.

Normal Growth of Healthy Infants Born from HIV+ Mothers Fed a Reduced Protein Infant Formula Containing the Prebiotics Galacto-Oligosaccharides and Fructo-Oligosaccharides: A Randomized Controlled Trial.

OBJECTIVE: The aim of the current study was to evaluate the safety of a new reduced protein (2.1 g/100 kcal) infant formula containing 4 g/L of 90% galacto-oligosaccharides (GOS) and 10% fructo-oligosaccharides (FOS). METHODS: Healthy term infants from Brazil were enrolled. Those born to human immunodeficiency virus (HIV)-positive mothers were randomized to a test (n = 65) or control (n = 63) formula group. Infants born to HIV-negative mothers were either exclusively breast-fed (n = 79) or received a mixed diet (breast milk and test formula, n = 65). Between 2 weeks and 4 months of age, infants were exclusively fed according to their assigned group. Anthropometric measurements were taken at baseline, 1, 2, 3, 4, 6, 8, 10, and 12 months. Digestive tolerance was evaluated during the first 4 months. The primary outcome was mean daily weight gain between 2 weeks and 4 months in the test formula and breast-fed groups. RESULTS: Data from all infants (N = 272) were used in the intention-to-treat (ITT) analysis and data from 230 infants were used in the per-protocol (PP) analysis. The difference in mean daily weight gain between 2 weeks and 4 months in the test formula and breast-fed groups was 1.257 g/day (one-sided 95% confidence interval [CI]: -0.705 to inf, P < 0.001) in the PP analysis, showing that the lower bound of the 95% CI was above the -3.0 g/day non-inferiority margin. Results were similar in the ITT analysis. Symptoms of digestive tolerance and frequency of adverse events were similar in the two groups. CONCLUSIONS: The formula containing 2.1 g/100 kcal protein and GOS and FOS was safe and tolerated well.

Cosavirus infection in persons with and without gastroenteritis, Brazil.

To determine possible cosavirus association with clinical disease, we used real-time reverse transcription PCR to test children and HIV-positive adults in Brazil with and without gastroenteritis. Thirteen (3.6%) of 359 children with gastroenteritis tested positive, as did 69 (33.8%) of 204 controls. Low prevalence, frequent viral co-infections, and low fecal cosavirus RNA concentrations argue against human pathogenicity.