[Detection of syncytial respiratory virus in clinical samples using a RT-PCR technique]

From November 2000 to May 2001, 208 clinical samples were analyzed for respiratory infection. Parallel to the detection of the syncytial respiratory virus (SRV) by solid phase immunoassay (EIA) and rapid culture in shell-vial or conventional tube, a reverse transcription polymerase chain reaction (RT-PCR) technique was developed. The procedures were complimentary and useful in the diagnosis of respiratory infections due to SRV, both in children and adults.

Safety, immunogenicity, and protective efficacy of one and three doses of the tetravalent rhesus rotavirus vaccine in infants in Lima, Peru

An oral rhesus-human rotavirus tetravalent (RRV-TV) vaccine (10(4) pfu of rhesus rotavirus [type G3] and of 3 human-rhesus reassortants [G1, G2, and G4]) was evaluated in a field trial in Lima, Peru. At 2, 3, and 4 months of age, infants received either a dose of RRV-TV, an initial dose of vaccine followed by a dose of placebo at 3 and 4 months, or a dose of placebo. Rotavirus-specific IgA responses were detected by ELISA in 75% of the three-dose vaccine group, 59% of the one-dose vaccine group (P = .05), and 24% of the placebo group (P < .001): 64%, 48%, and 12% of each group, respectively, had a neutralizing antibody response to at least 1 serotype. Both one and three doses of vaccine failed to induce a significant level of protection against rotavirus diarrhea; however, they did provide some protection (range, 35%-66%) against more severe rotavirus diarrhea, especially for episodes caused by type G1.

Incidence of Vibrio cholerae O1 diarrhea in children at the onset of cholera epidemic in periurban Lima, Peru

OBJECTIVE

To determine the incidence of Vibrio cholerae O1-associated diarrhea in children during the onset of the 1991 cholera epidemic in Peru.

METHODS

Stool cultures were obtained from children (mean age, 26 months) participating in a prospective community-based study of diarrhea in a periurban community in Lima between February and May, 1991.

RESULTS

Of the 409 diarrheal episodes cultured V. cholerae O1 was isolated in 14 (3.4%) episodes. This represented an incidence of 0.11 episode per child year, higher than previously reported rates in children from endemic cholera areas. Most cases were mild; only 1 case required hospitalization.

CONCLUSIONS

Our study indicates that from the beginning of this epidemic, V. cholerae O1 caused diarrhea in children as well as adults and should therefore be considered as one of the possible pathogens when children from a cholera-affected area develop diarrhea.

Immunogenicity, safety and protective efficacy of one dose of the rhesus rotavirus vaccine and serotype 1 and 2 human-rhesus rotavirus reassortants in children from Lima, Peru

In a four cell trial, a single 10(4) plaque-forming unit dose of rhesus rotavirus (RRV) vaccine (serotype G3), a human rotavirus-rhesus rotavirus reassortant vaccine with serotype G1 specificity, a similar vaccine with serotype G2 specificity, or a placebo was administered with buffer orally at 2 months of age to 800 Peruvian infants. Only the RRV vaccine was associated with a febrile response (< 38 degrees C) that occurred in 9% of the infants on day 4 after vaccination. Diarrhea or other side-effects were not associated with administration of vaccine. Vaccine strains were shed by only 12-18% of the infants as determined by examination of a single stool specimen obtained on days 4 or 5 after vaccination. Fifty per cent of vaccines developed an IgA ELISA seroresponse; however, a serotype-specific seroresponse by plaque reduction neutralization was demonstrated in < 20% of the participants against each of the three candidate vaccine strains. Vaccine efficacy was evaluated by twice-weekly home surveillance for diarrheal diseases during 24 months post-immunization. Rotavirus diarrheal episodes were identified by ELISA. Only the RRV vaccine had a significant protective efficacy (29%, p = 0.03, chi-square test) against rotavirus diarrhea. Analysis of vaccine efficacy against rotavirus episodes of any severity in which no other enteropathogen was isolated showed a trend towards higher vaccine efficacy. In addition, a similar trend was observed in rotavirus-only episodes in which there was some degree of dehydration or when health services were utilized. Serotype G1 or G2 rotavirus strains were most prevalent during surveillance. Neither serotype G1 or serotype G2 vaccines were protective against serotype 1 or 2 rotavirus diarrhea, respectively. The serotype G2 vaccine was 84% protective against serotype 1 and 2 dehydrating rotavirus diarrhea in the small numbers of individuals evaluated. We conclude that one dose of 10(4) p.f.u. of the RRV, serotype G1, or serotype G2 rotavirus vaccine failed to induce either an adequate serotype-specific seroresponse or serotype-specific protection in children immunized at 2 months of age. Only the RRV vaccine induced a low level of protection against rotavirus diarrhea mainly of serotype G1 specificity. Future studies need to explore whether higher vaccine dose and/or more than one dose would increase the immunogenicity and efficacy of the rotavirus vaccine, especially in developing countries with a high level of baseline rotavirus antibodies.

Effect of acute maternal infection on quantity and composition of breast milk

To investigate the potential effects of maternal infection during lactation on breast-milk quantity and composition, we examined low-income Peruvian women who had an acute febrile infection and were exclusively breast-feeding a child from 1 to 6 mo of age (n = 36). Women who were not ill (n = 38) served as controls; all women had body mass indexes (in kg/m2) > 19.5. Blood and milk samples were collected on days 1, 7, and 14 after identification of the episode of illness. C-reactive protein in maternal serum was significantly elevated by infection, whereas two other acute-phase reactants, ceruloplasmin and alpha 2-macroglobulin, showed no change. Serum zinc concentrations were significantly lower in ill women than in women who were not ill, whereas serum copper concentrations were elevated initially in ill women. Serum iron concentrations increased significantly with time, but there was no significant difference between groups. Milk intake, as assessed by 12-h test-weighing, was not affected by the infection. Concentrations of milk total protein, casein, and whey proteins were similar in the two groups and there was no significant effect of illness on milk trace element concentrations. Thus, acute maternal infections during established lactation did not affect milk volume, milk protein, or trace element concentrations, despite expected changes in serum protein and trace element concentrations.

Potential magnitude of the misclassification of a population's trace element status due to infection: example from a survey of young Peruvian children

To examine the effects of concurrent infection on population-based assessment of trace element status, we collected data on clinical signs and laboratory indicators of infection when obtaining blood for serum zinc, copper, and ferritin analyses in 153 Peruvian children aged 11-19 mo. Fifty-two (34.7%) of the children had some reported sign of infection and 43 (28.3%) had elevated C-reactive protein concentrations or leukocytosis. Children with any evidence of infection had marginally lower mean (+/- SD) serum zinc concentrations (7.0 +/- 2.3 vs 7.5 +/- 2.0 mumol/L, P = 0.16) and significantly greater serum copper (24.7 +/- 4.7 vs 22.7 +/- 4.2 mumol/L, P = 0.006) and serum ferritin concentrations (10.0 +/- 12.9 vs 3.9 +/- 4.4 micrograms/L, P < 0.001) than did those without infections. Infection caused an underestimation in the rate of low copper status by 1 percentage point and low iron status by 12 percentage points. Thus, the effect of concurrent infections is of variable magnitude and may differ by nutrient, nutritional status of the population, and prevalence and severity of infections.

Safety, immunogenicity, and excretion pattern of single-dose live oral cholera vaccine CVD 103-HgR in Peruvian adults of high and low socioeconomic levels

Groups of 122 Peruvian adults of low socioeconomic level (SEL) and 125 of high SEL received a randomly allocated 5 x 10(9)- or 5 x 10(8)-CFU dose of CVD 103-HgR live oral cholera vaccine or a placebo. The vaccine was well tolerated. Vibriocidal seroconversions occurred in 78% of high-SEL and 72% of low-SEL subjects who ingested the high dose and in 78 and 49%, respectively, of those who received the low dose.