High seroprevalence of antibodies against dengue virus in a prospective study of schoolchildren in Managua, Nicaragua

Abstract

SummaryTo investigate the incidence of dengue virus (DENV) infection in Nicaragua, a 2-year prospective study was conducted in schoolchildren 4-16 years old in the capital city of Managua. Blood samples were collected before the rainy season in 2001, 2002 and 2003, and were assayed for DENV-specific antibodies. Participants were monitored for dengue-like illness, and acute and convalescent blood samples were collected from suspected dengue cases. In 2001 and 2002, 602 and 397 students were recruited, respectively, and paired annual serum samples were available from 467 and 719 participants in 2001-2002 and 2002-2003, respectively. The overall seroprevalence of anti-DENV antibodies was 91%, increasing from 75% at age 4 to 100% at age 16. The incidence of DENV infection was 12% in Year 1 and 6% in Year 2 (P < 0.001). During Year 1, four laboratory-confirmed dengue cases were detected, with one DENV2 isolate; during Year 2, there were six confirmed dengue cases, with one DENV1 isolate. These and additional circulating serotypes were confirmed by plaque reduction neutralisation test. This study demonstrates surprisingly high transmission of DENV in urban Nicaragua.

Incidence of Dengue Virus Infection in School-Aged Children in Puerto Rico: A Prospective Seroepidemiologic Study

“…Our seroincidence rate was also comparable with the rates found in prospective cohort studies conducted in Central and South America (5.8-11.1%). 29,31,33 The similarity between our 1-year DENV seroincidence rates and other study populations suggests that Patillas and likely, Puerto Rico can also experience higher rates of DENV transmission.…”

“…[27][28][29]31 The reason for these differences is multifactorial and likely related to host population immune profile, DENV transmission patterns, DENV serotype/strain differences, and intensity of AFI monitoring. 34 For example, it seems that AFI detection methods used in studies may affect estimation of symptomatic-to-inapparent DENV infection ratios, because studies that used active AFI monitoring methods (e.g., school absence monitoring with student and parent follow-up) tended to report higher symptomaticto-inapparent DENV infection ratios (1:0.9-1:2.9) than studies using passive AFI monitoring methods (e.g., instructing participants to visit the study clinic when ill/no active followup; ratio = 1: 1.3-1:18).…”

Index Cluster Study of Dengue Virus Infection in Nicaragua

“…DENV-specific IgM was detected by using a single-dilution IgM-capture enzyme-linked immunosorbent assay (ELISA), 13 and total antibodies to DENV were measured by using an inhibition ELISA 4,14,15 and analyzed using the method of Reed and Muench 16 to confirm serologic diagnosis and to distinguish primary and secondary DENV infections. Both serologic assays were performed on paired day 1 and day 14 serum samples.…”

“…A primary DENV infection was defined when the antibody titer was < 10 in the day 1 sample and/or < 2,560 in the day 14 sample as determined by inhibition ELISA. 4 Secondary DENV infection was defined by inhibition ELISA as an antibody titer ≥ 10 in the day 1 sample and/or ≥ 2,560 in the day 14 sample. 15,22 Symptomatic cases were those meeting the World Health Organization definition (as described above) or with fever without a defined focus (undifferentiated febrile illness), as determined by signs and symptoms collected by field teams at enrollment and follow-up and by study physicians at the HCSFV, together with complete blood count results.…”

“…However, data from several studies around the world, [1][2][3] including Nicaragua, 4,5 indicate that 50-90% of dengue virus (DENV) infections are inapparent. An ongoing pediatric cohort study in Managua, Nicaragua, enables detection of the number of inapparent DENV infections that occur each year by analyzing titers of antibodies to DENV in yearly blood samples, but does not permit their identification at the moment that they occur.…”