Two-year study of the protective efficacy of the oral whole cell plus recombinant B subunit cholera vaccine in Peru.

The protective efficacy of an oral inactivated whole cell Vibrio cholerae plus recombinant B subunit cholera vaccine was determined against El Tor cholera among Peruvian children and adults (2-65 years old) in a randomized, double-blind manner. Study subjects received 2 doses of vaccine or placebo 2 weeks apart, followed by a booster dose 10 months later. Surveillance for cholera was performed actively, with 2 visits per week to each household, and passively, at a local hospital. Stool samples were collected during diarrhea episodes and were cultured for V. cholerae. A total of 17,799 persons received 2 doses of vaccine or placebo, and 14,997 of these persons received the booster dose. After 2 doses (first surveillance period), V. cholerae biotype O1 was isolated from 17 vaccinees and 16 placebo recipients, demonstrating vaccine efficacy (VE) of -4%. After 3 doses (second surveillance period), V. cholerae O1 was isolated from 13 vaccinees and 32 placebo recipients, demonstrating VE of 61% (95% confidence interval ¿CI, 28%-79%). In the second surveillance period, the VE for illness requiring hospitalization was 82% (95% CI, 27%-96%). VE was also higher for persons >15 years old (VE, 72%; 95% CI, 28%-89%).

Nutritional status of Helicobacter pylori-infected children in Guatemala as compared with uninfected peers.

The effect of Helicobacter pylori infection on the nutritional status of children in a developing country was studied using a cross-sectional design. Children attending an all-girl public school in inner Guatemala City, Guatemala were evaluated to acquire sociodemographic information and anthropometric nutritional parameters (weight-for-height [WFH] and height-for-age [HFA]), and detect H. pylori-specific serum IgG antibodies. Of 211 children 5-10 years of age, 107 (51%) were infected. The WFH values were not different between infected and uninfected subjects, and were not affected by the sociodemographic variables. The HFA values decreased significantly with age (P = 0.008), lower income (P = 0.04), and H. pylori infection (P = 0.05). When controlled for age and income level, the effect of infection on HFA became nonsignificant (P = 0.30). Helicobacter pylori appeared to have no effect on the nutritional status of the studied children; the differences detected were small and likely due to sociodemographic factors.

Dietary risk factors associated with the transmission of Helicobacter pylori in Lima, Peru.

The factors influencing the risk of acquisition of Helicobacter pylori infection are not well established. One hundred four children (0-17 years of age) requiring an endoscopy for the evaluation of gastrointestinal symptoms had demographic and dietary data collected and biopsy specimens of the gastric antrum stained for the identification of H. pylori. The 52 (50%) infected subjects were significantly older than the uninfected ones with no difference in gender, crowding, source of drinking water, or exposure to domestic animals. Increased prevalence of infection was associated with increased consumption of food from street vendors, and decreased consumption of fruits in the subgroup that denied consuming food from street vendors. No association was found with consumption of fish, chicken, beef, beans, vegetables, rice, cheese, milk, and unboiled water. These findings support the role of food prepared under unhygienic conditions as a probable mechanism of transmission of H. pylori in developing countries.

Helicobacter pylori infection in children with abdominal ailments in a developing country.

Helicobacter pylori commonly infects children in developing countries. To determine the frequency of this infection and its potential role in specific gastrointestinal entities, all patients requiring upper gastrointestinal endoscopy for the evaluation of abdominal ailments in a gastroenterology practice in Lima, Peru, were evaluated during a 1-year period. Gastric biopsies were obtained for each child and were stained with hematoxylin-eosin and Warthin-Starry stains. Of the 107 evaluable patients (mean age 7.4 years, 58% boys), 52 (49%) were infected. The infection rate increased with older patients (P = 0.004). Children with recurrent abdominal pain (P = 0.04), an endoscopic finding of nodular gastritis (P = 0.007), and a histologic finding of chronic active gastritis (P < 0.0001) were infected more commonly.

Treatment of cutaneous sporotrichosis with one daily dose of potassium iodide.

BACKGROUND: Recommended treatment for cutaneous sporotrichosis consists of a saturated solution of potassium iodide (SSKI) administered in three daily doses (tid). Because compliance with this regimen has been a problem in our previous experience, we evaluated the use of one daily (qd) full dose of SSKI. METHODS: Patients with culture-confirmed cutaneous sporotrichosis were entered in a randomized, nonblinded study to compare the safety and efficacy of qd vs. tid dosage of SSKI. RESULTS: Fifty-seven patients were enrolled to receive either qd (29) or tid (28) SSKI. Three (1 in the qd and 2 in the tid group) were not compliant with the assigned regimen. Side effects were common but mild in both treatment groups (61% in the qd and 42% in the tid group, P = 0.17); treatment had to be discontinued because of side effects in 3 cases (2 in the qd and 1 in the tid group). Overall 26 (89.6%) and 25 (89.2%) of the individuals initially assigned to the qd and tid dosing schedule, respectively, were cured by the treatment. No relapse was detected after 45 days of follow-up. CONCLUSION: These findings suggest that a single daily full dose of SSKI appears to be appropriate therapy for cutaneous sporotrichosis; further studies with larger numbers of patients are required.

Immunogenicity in Peruvian volunteers of a booster dose of oral cholera vaccine consisting of whole cells plus recombinant B subunit.

Forty-nine subjects received two doses of oral cholera vaccine consisting of whole cells plus recombinant B subunit; this was followed by a booster dose one year later. After the primary series, a significant (greater than twofold) increase in the levels of vibriocidal, anti-cholera toxin immunoglobulin G and anti-cholera toxin immunoglobulin A antibodies occurred in 54, 88, and 81% of the subjects, respectively. Within one year, titers decreased to levels close to baseline. A booster dose then induced rises to those which occurred after the initial vaccination. The results suggest that 1-year booster doses may be necessary to maintain immunity against cholera in Latin America.

Community-based assessment of safety and immunogenicity of the whole cell plus recombinant B subunit (WC/rBS) oral cholera vaccine in Peru.

Every year since its introduction in 1991, there have been epidemics of cholera in Lima, Peru. Vaccination is one approach to the control of cholera. A pilot study was conducted to assess the safety and immunogenicity of a whole cell plus recombinant B subunit (WC/rBS) cholrea vaccine in Lima, Peru. Five hundred and forty-one volunteers aged 2-65 years received two doses two weeks apart of WC/rBS vaccine or Escherichia coli K12 placebo administered in bicarbonate buffered water. Symptoms were monitored on all subjects and blood was collected from 102 persons before the first dose and two weeks after the second dose. Mild post-vaccination gastrointestinal symptoms were reported with equal frequency for both the vaccine and placebo recipients. Among 51 vaccines, 49% had a twofold or greater increase in serum vibriocidal titers (GMT = 78; range < 1:10 to 1:5120); and 92% and 82% developed a twofold or greater serum anti-cholera toxin IgG and IgA response, respectively. Persons with elevated prevaccination vibriocidal titers had a decreased response to the WC/rBS. Age and blood group did not affect the immune response. The WC/rBS vaccine was safe and immunogenic in a group of native Peruvians.

Diarrheal disease in Peru after the introduction of cholera.

Surveillance was conducted one day each week from December 1992 through May 1993 to determine the clinical features and etiology of diarrhea among a population in a suburban community of Lima, Peru. Patients who had had three or more loose stools during the previous 24 hr were enrolled at a clinic located in the community or at a nearby regional hospital. A total of 143 cases of diarrhea were detected for an overall rate of 7.1 cases per 1,000 population. The enteropathogens isolated were Vibrio cholerae 01 (31%), enterotoxigenic Escherichia coli (22%), and Salmonella, Shigella, Campylobacter, and Aeromonas species (10%). Specimens from the remaining cases were negative for enteropathogens. All isolates of V. cholerae were susceptible to tetracycline, doxycycline, nalidixic acid, norfloxacin, trimethoprim-sulfamethoxazole, trimethoprim, gentamicin, chloramphenicol, and cephalothin. Cases of diarrhea associated with V. cholerae were more common among adults, and more likely to experience severe dehydration and require hospitalization than the non-cholera cases. Data indicated that among the cases diagnosed, V. cholerae and enterotoxigenic E. coli were the more common causes of diarrhea in a suburban community of Lima during the summer season.

Protective efficacy of oral whole-cell/recombinant-B-subunit cholera vaccine in Peruvian military recruits.

The cholera epidemic in South America has reinforced the need for safe and effective oral vaccines. In a randomised, double-blind, placebo-controlled efficacy trial among 1563 Peruvian military recruits we have investigated the protective efficacy of an oral inactivated whole-cell/recombinant-B-subunit (WC/rBS) cholera vaccine. Participants were given two oral doses of cholera vaccine or Escherichia coli K12 placebo, with an interval of 7-14 days. 1426 (91%) subjects received the two prescribed doses and were followed up for a mean of 18 weeks (median 21 weeks). After vaccination, Vibrio cholerae O1 El Tor Ogawa was isolated from 17 subjects with diarrhoea. 16 of the cholera cases occurred 2 weeks or longer after the second dose of vaccine (14 placebo recipients, 2 vaccinees). We also detected 14 symptomless infections (11 [7 placebo recipients, 4 vaccinees]) 2 weeks or longer after the second dose. The vaccine had significant protective efficacy against cholera (86% [95% CI 37-97], p < 0.01) but not against symptomless infection (42% [-96 to 85]). All cholera cases were in people of blood group O, who made up 76% of the study population (p < 0.01). Two doses of WC/rBS vaccine, given 1 to 2 weeks apart, provide rapid, short-term protection against symptomatic cholera in adult South Americans, who are predominantly of blood group O. Long-term efficacy studies in Peruvian adults and children are under way.