Carole A. were an important component of the total dengue immunity profile. Introduction Dengue is an acute, arthropod-borne, flavivviral disease that occurs in a global belt of tropical and subtropical countries. Illness is caused by one of four serotypes of dengue virus (DENV) and spread by species mosquitoes, most commonly malaria as described.18 This antigen is a marker of prior exposure to malaria,17 a commonly postulated cause of febrile illness in children in Haiti. All serum samples were screened by using rapid whole blood HIV antibody tests (Determine HIV 1/2; Abbott Laboratories, Abbott Park, IL or Capillus HIV 1 and 2; Trinity Biotech, Bray, Ireland). Data analysis. For purpose of analysis, the children were divided into six-month age blocks (7C12 months, 13C18 months, etc.). The frequency and magnitude of strain-specific antibody to DENV were the primary data for analysis. Results The GHESKIO Center, located in a densely populated, low-lying, urban area in Port-au-Prince, Haiti, serves primarily as a site for HIV counseling, testing, and treatment of local populations. Housing was marginal even before the earthquake of January 12, 2010; many of the GHESKIO patients lived in adjacent slums (Cite de L’Eternal and Cite de Dieu) that had no electricity or sanitation, inadequate nutrition, and frequent flooding. Voluntary HIV testing performed for more than 27,000 persons per year demonstrates a 15% prevalence of HIV infection in the population served. More than 8,000 persons are currently being treated with highly active antiretroviral therapy within the GHESKIO network. A special emphasis is placed on the prevention of mother-to-child transmission of HIV, and children born to HIV-infected mothers are carefully followed postpartum for evidence of HIV infection.19 Participants and study design. The age range of the children was 7C36 months (mean age = 18.6 months, median age = 16.9 months, and intraquartile age range = 11.9C24.3 months). Of the 166 children, 76 were girls and 90 were boys. The children had recorded addresses throughout Port-au-Prince. Use of these U-101017 samples, originally obtained to determine HIV status, for assays of DENV and malaria antibody and review of clinical histories was reviewed and approved by the GHESKIO, Vanderbilt University, and Cornell Institutional Review Boards under conditions in which the identity of the child remained anonymous. Only two of the 166 patients were ultimately shown to have HIV. Thus, perinatally acquired HIV infection in the children did not substantially influence the results, although HIV infection is often a marker in a family in Haiti for poverty and sub-standard living conditions. Seroprevalence of neutralizing antibodies to DENV. A total of 108 (65%) of 166 infants and young children had serum antibody to at least one DENV serotype (Figure 1 and Table 1). Twenty-six (53%) of 49 infants tested who were 7C12 months of age had already been infected. However, the percentage infected did not increase asymptotically and had reached only 10 (65%) of 16 children who were 30C36 months of age. The pattern of acquisition raises the possibility that there had been lower levels of DENV transmission in the period 2C3 years prior to sampling, and that virtually all infections had occurred in the previous year. Open in a separate window Figure 1. Antibody to dengue virus within each age group during the period sampled, Haiti. Each line represents the prevalence of the serotype indicated, and the top line represents the combined U-101017 prevalence of antibody to any dengue serotype. Table 1 Serotype-specific antibody to dengue virus as a function of age, Haiti* malaria in the age group and during the seasons studied. This finding is corroborated by the rarity with which positive malaria smears are seen at GHESKIO. In spite of requesting 5C7 smears a week from the pediatric population, a positive malaria smear is definitely reported less than once a month. Conversation A well-standardized and quantified serotype-specific DENV plaque neutralization assay was performed on cautiously stored medical samples from pediatric sera and shown that DENV illness in the urban poor in Haiti is definitely hyperendemic. Most children 7C12 months of age experienced already experienced a DENV illness with one of at least three types, DENV types 1, 2, and 3. Illness with a strain gave not only high strain-specific antibody but appears to induce cross-reactive neutralizing antibody to the one or more additional DENV serotypes. There was no significant increase in U-101017 geometric mean titer with age. This finding, coupled with the rare instances in which Rabbit polyclonal to TNFRSF10D equivalent titers were seen against more than one strain, suggests that broad immunity may be induced by main illness no matter strain. If reinfection having a heterotypic disease occurred individually of initial illness, one might have expected to observe multiple comparably high antibody titers. Thus, one probability raised by this survey is that frequent early exposure to DENV with resultant broadly cross-neutralizing.