No abstract

Abstract. Data from a six-year follow-up of Trypanosoma cruzi−infected adolescents enrolled in a randomized, double-blind, clinical trial of benznidazole showed successful chemotherapy in 64.7% (95% confidence interval [CI] ‫ס‬ 50.2−78.7) and 84.7% (95% CI ‫ס‬ 66.8−92.9), respectively, by intention-to treat and by per protocol analysis measured by seronegativity in a chemiluminescent enzyme-linked immunosorbent assay with a purified trypomastigote mucin antigen. No incident case of cardiomyopathy was detected by electrocardiogram assessment in this cohort of adolescents who had been infected in childhood. The persistent and consistently long-term negative serologic reactions suggest the absence of the parasite in the treated patients and reinforces the recommendation of early benznidazole chemotherapy for T. cruzi-infected infants as a public health policy in endemic areas.While the elimination of Chagas disease has been considered a reasonable public health goal, 1 controversies remain about the efficiency of trypanocidal chemotherapy, especially in chronic asymptomatic individuals. Currently, there is a need to find appropriate drugs or therapeutic regimens with existing drugs that can be used in Trypanosoma cruzi−infected individuals to prevent development of severe clinical forms of Chagas disease. In a previous randomized, double-blind, clinical trial carried out among infants in Brazil, we showed that a 60 day-course of benznidazole in patients with early chronic infections with T. cruzi was safe and effective in 55.8% of the children, as shown by seronegative conversion of specific antibodies after a 38-month follow-up, when compared with the placebo group.2 In addition, a short-term effect of benznidazole on the prevention of cardiac damage was also observed. A similar efficacy (62%) for benznidazole was also observed in a study conducted in Argentinean children.

Nasopharyngeal carriage of Streptococcus pneumoniae is a key factor in the development of invasive disease and the spread of resistant strains within the community. A single nasopharyngeal swab was obtained from 648 unvaccinated children aged <5 years, either healthy or with acute respiratory tract infection or meningitis, during the winters of 2000 and 2001. The overall pneumococcal carriage rate was 35.8% (95% CI 32.1-39.6). The pneumococcal serotypes found most frequently in the nasopharynx were 14, 6B, 6A, 19F, 10A, 23F and 18C, which included five of the seven serotypes in the currently licensed seven-valent conjugate vaccine (PCV7); serotypes 4 and 9V were less common. Serotypes 1 and 5 were isolated rarely from the nasopharynx. A comparison of 222 nasopharyngeal isolates with 125 invasive isolates, matched for age and time to the carrier isolates, showed a similar prevalence of penicillin non-susceptible pneumococci (PNSp) (19.8% and 19.2%, respectively). PNSp serotypes were similar (6B, 14, 19F, 19 A, 23B and 23F) for carriage and invasive disease isolates. The coverage of PCV7 for carriage isolates (52.2%) and invasive isolates (62.4%) did not differ significantly (p 0.06); similarly, there was no significant difference in PCV7 coverage for carriage isolates (34.5%) and invasive isolates (28.2%) of PNSp. These data suggest that PCV7 has the potential to reduce pneumococcal carriage and the number of carriers of PNSp belonging to vaccine serotypes.

A survey of nasopharyngeal (NP) carriage of penicillin nonsusceptible pneumococcal (PNSp) isolates was conducted among 1,192 children attending 62 day care centers in Brazil, where pneumococcal vaccination has still not been introduced routinely. NP pneumococcal carriage was detected in 686 (57.6%) infants, and 178 (25.9%) of them carried PNSp isolates. Being less than 24 months of age, hospitalization in the previous three months, and recurrent acute otitis media were independently associated with PNSp. Serotypes 14, 23F, 19A, 6A, 6B and 19F were the most common serotype isolated accounting for 80% of the PNSp. A high proportion (35/332) of non(sero)-typeable isolates was detected, 62.9% of them PNSp. Serotypes coverage projected for the PCV13-valent vaccine (72%) was significantly higher compared to PCV7 (58.4%) and PCV10-valent vaccine (59.3%).

Under programme conditions the effectiveness of Hib conjugate vaccine in infants with radiologically confirmed pneumonia was 31% (95% CI: -9%, 57%) showing the potential benefit of Hib immunization in the prevention of likely non-bacteraemic pneumonia.