Incidence of confirmed and suspected dengue cases and expansion factors.

1<p>2–9 years old in 2004–5, 2–10 in 2005–6, 2–11 in 2006–7 and 2–12 in 2007–9 (the cohort aged by one year each year).</p>2<p>Includes all subjects active in the cohort for at least half of the study year, whether or not an annual sample was taken at the end of the year.</p>3<p>1–14 years old in 2004–5 and 2–14 years old for all other years.</p>4<p>Expansion factor  =  PDCS incidence of confirmed dengue/Managua NES incidence of confirmed dengue.</p>5<p>Includes suspected cases that met WHO criteria (see <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000633#s2" target="_blank">Materials and Methods</a>); cases of undifferentiated fever, which account for 25% of laboratory-confirmed dengue cases in the PDCS, are not included in this figure.</p>6<p>Suspected dengue cases are defined by the NES according to WHO criteria (see <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0000633#s2" target="_blank">Materials and Methods</a>).</p>7<p>Expansion factor  =  PDCS incidence of suspected dengue/Managua NES incidence of suspected dengue.</p>8<p>Includes symptomatic cases identified only among those subjects who completed the study year and for which paired annual samples were available for determination of inapparent infection (n = 152, of 159 symptomatic dengue cases among cohort participants identified in 2004–8).</p

Reported laboratory-confirmed dengue cases among children in Managua health centers and in the PDCS, 2004–8.

<p>Laboratory-confirmed dengue cases among 1–14 year-old children in 2004–5 and 2–14 year-old children in 2005–8 reported in Managua health centers by the NES and in 2–12 year-old children meeting the WHO case definition in the PDCS 2004–8.</p

The Nicaraguan Pediatric Dengue Cohort Study: Incidence of Inapparent and Symptomatic Dengue Virus Infections, 2004–2010

<div><p>Dengue, caused by the four serotypes of dengue virus (DENV), is the most prevalent mosquito-borne viral disease of humans. To examine the incidence and transmission of dengue, the authors performed a prospective community-based cohort study in 5,545 children aged 2–14 years in Managua, Nicaragua, between 2004 and 2010. Children were provided with medical care through study physicians who systematically recorded medical consult data, and yearly blood samples were collected to evaluate DENV infection incidence. The incidence of dengue cases observed was 16.1 cases (range 3.4–43.5) per 1,000 person-years (95% CI: 14.5, 17.8), and a pattern of high dengue case incidence every other year was observed. The incidence of DENV infections was 90.2 infections (range 45.2–105.3) per 1,000 person-years (95% CI: 86.1, 94.5). The majority of DENV infections in young children (<6 years old) were primary (60%) and the majority of infections in older children (≥9 years of age) were secondary (82%), as expected. The incidence rate of second DENV infections (121.3 per 1,000 person-years; 95% CI: 102.7, 143.4) was significantly higher than the incidence rate of primary DENV infections (78.8 per 1,000 person-years; 95% CI: 73.2, 84.9). The rigorous analytic methodology used in this study, including incidence reporting in person-years, allows comparison across studies and across different infectious diseases. This study provides important information for understanding dengue epidemiology and informing dengue vaccine policy.</p></div

Performance of the QuickVue Influenza A+B Rapid Test for Influenza A H1N1pdm, Managua, Nicaragua, 2009.

<p>Performance of the QuickVue Influenza A+B Rapid Test for Influenza A H1N1pdm, Managua, Nicaragua, 2009.</p

Frequency of dengue-positive episodes that met the WHO classification criteria for suspected dengue by age (n = 181).

<p>Upon presentation to the health center or hospital, children with a febrile illness were classified according to whether or not they met the WHO classification criteria for suspected dengue. One patient had two dengue virus infections over the course of the study and is represented twice. n = 6 for age 2, n = 10 for age 3, n = 18 for age 4, n = 23 for age 5, n = 21 for age 6, n = 16 for age 7, n = 21 for age 8, n = 23 for age 9, n = 24 for age 10, n = 19 for age 11+. Chi-square test for trend 5.977, p = 0.01. WHO, World Health Organization.</p

Incidence of DENV infections, Managua, Nicaragua, 2004–2010.

<p>The number of DENV infections from 2004–2005 to 2007–2008 has been previously reported <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002462#pntd.0002462-Balmaseda3" target="_blank">[16]</a>. The number of inapparent DENV infections in this paper vary slightly from our previous report due to the implementation of new quality control procedures which resulted in several revisions to the inapparent infection data.</p

Incidence of dengue cases, Managua, Nicaragua, 2004–2010.

<p>The number of dengue cases from 2004–2005 to 2007–2008 has been previously reported <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002462#pntd.0002462-Balmaseda3" target="_blank">[16]</a>.</p

Characteristics of study participants by dengue testing results and disease severity (n = 1,974).

<p>Numbers represent episodes of febrile illness. DENV, dengue virus; OFI, other febrile illness; DF, dengue fever; Severe dengue = dengue hemorrhagic fever (DHF), dengue shock syndrome (DSS), dengue with signs associated with shock (DSAS), or dengue fever with compensated shock (DFCS).</p>a<p>Includes 9 DHF, 4 DSS, 3 DSAS, and 4 DFCS cases.</p>b<p>Percentages are calculated horizontally for dengue season.</p>c<p>Includes 1 case each of DENV-1/DENV-2 and DENV-1/DENV-4.</p

Incidence of primary and secondary DENV infections, Managua, Nicaragua, 2004–2010.

<p>The number of primary and secondary DENV infections from 2004–2005 to 2007–2008 has been previously reported <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002462#pntd.0002462-Balmaseda3" target="_blank">[16]</a>.</p

Flowchart of clinical and laboratory protocols for study participants in the Pediatric Dengue Cohort Study.

<p>Of the 1,974 episodes of febrile illness in the Pediatric Dengue Cohort Study from August 2004 to June 2009 that met the WHO classification criteria for suspected dengue or were diagnosed with undifferentiated fever, 405 patients presented with febrile illness on 2 occasions, 105 presented on 3 occasions, 21 presented on 4 occasions, and 5 presented on 5 occasions. One patient presented after day 8 of illness and was excluded from analysis. Twenty-nine patients had cause of fever identified later in the course of illness. CBC, complete blood count; WHO, World Health Organization; UTI, urinary tract infection.</p