Reported and estimated number of clincial dengue cases in Puerto Rico, 2005–2010 (with 95% CI).

<p>Panel A: Reported and Estimated Dengue Inpatients; Panel B: Reported and Estimated Dengue Outpatients. Notes: MA = Medically Attended patient classification sub-model which includes all patients who either had a completed Dengue Case Information Form (DCIF), or had some indication in their medical records (such as specimens sent to a laboratory for dengue testing) as potentially having a clinical case of dengue. DO = In this patient classification sub-model, labeled “DCIF Only (DO),” we included only those patients (in or out) definitively recorded as potential dengue case on a DCIF. See text for further details. The 95% CI (confidence interval) is the range between the 2.5% and 97.5% confidence estimates.</p

Reported and estimated rate of medically attended dengue per 1,000 general population in Puerto Rico (2005 to 2010).

<p>Reported and estimated rate of medically attended dengue per 1,000 general population in Puerto Rico (2005 to 2010).</p

Sensitivity analysis: Relative importance of individual multipliers in calculating the overall multiplier for reported dengue inpatients: Puerto Rico, 2010.

<p>Notes: a: Graph plots relative importance of the individual multipliers used to calculate the overall multiplier. The wider the plotted range (i.e., bar), the greater the change in the overall multiplier. b: Results calculated for MA = Medically Attended patient classification sub-model which includes all patients who either had a completed Dengue Case Information Form (DCIF), or had some indication in their medical records (such as specimens sent to a laboratory for dengue testing) as potentially having a clinical case of dengue. PDSS = Passive dengue surveillance system. EDSS = Enhance dengue surveillance system. IgM = Immunoglobulin M. Test indicates presence of dengue IgM antibodies using an antibody capture enzyme-linked immunosorbent assay. PCR = Polymerase chain reaction. Test indicates evidence of dengue RNA using by a Reverse transcription polymerase chain reaction (RT-PCR) test. See main text for detailed description of individual multipliers and how they are used to calculate the overall multiplier.</p

Estimates of dengue overall multiplier for inpatients in Puerto Rico: 2005 to 2010^a.

<p>Estimates of dengue overall multiplier for inpatients in Puerto Rico: 2005 to 2010<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0006650#t002fn001" target="_blank">^a</a>.</p

Schematic of model to estimate multipliers to correct for under-reporting of outpatient and hospitalized dengue cases.

<p>Notes; Multiplier D (only) is used for the inpatient module. Multiplier D and Multiplier E are used for the outpatient module. See text for further details. PDSS = Passive dengue surveillance system. EDSS = Enhanced dengue surveillance system. CDC-DB = U.S. Centers for Disease Control and Prevention, Dengue Branch (stationed in San Juan, Puerto Rico).</p

Use of Household Cluster Investigations to Identify Factors Associated with Chikungunya Virus Infection and Frequency of Case Reporting in Puerto Rico

<div><p>Background</p><p>Chikungunya virus (CHIKV) is transmitted by <i>Aedes</i> species mosquitoes and is the cause of an acute febrile illness characterized by potentially debilitating arthralgia. After emerging in the Caribbean in late 2013, the first locally-acquired case reported to public health authorities in Puerto Rico occurred in May 2014. During June–August 2014, household-based cluster investigations were conducted to identify factors associated with infection, development of disease, and case reporting.</p><p>Methodology/Principal Findings</p><p>Residents of households within a 50-meter radius of the residence of laboratory-positive chikungunya cases that had been reported to Puerto Rico Department of Health (PRDH) were offered participation in the investigation. Participants provided a serum specimen and answered a questionnaire that collected information on demographic factors, household characteristics, recent illnesses, healthcare seeking behaviors, and clinical diagnoses. Current CHIKV infection was identified by rRT-PCR, and recent CHIKV infection was defined by detection of either anti-CHIKV IgM or IgG antibody. Among 250 participants, 74 (30%) had evidence of CHIKV infection, including 12 (5%) with current and 62 (25%) with recent CHIKV infection. All specimens from patients with CHIKV infection that were collected within four days, two weeks, and three weeks of illness onset were positive by RT-PCR, IgM ELISA, and IgG ELISA, respectively. Reporting an acute illness in the prior three months was strongly associated with CHIKV infection (adjusted odds ratio [aOR] = 21.6, 95% confidence interval [CI]: 9.24–50.3). Use of air conditioning (aOR = 0.50, 95% CI = 0.3–0.9) and citronella candles (aOR = 0.4, 95% CI = 0.1–0.9) were associated with protection from CHIKV infection. Multivariable analysis indicated that arthralgia (aOR = 51.8, 95% CI = 3.8–700.8) and skin rash (aOR = 14.2, 95% CI = 2.4–84.7) were strongly associated with CHIKV infection. Hierarchical cluster analysis of signs and symptoms reported by CHIKV-infected participants demonstrated that fever, arthralgia, myalgia, headache, and chills tended to occur simultaneously. Rate of symptomatic CHIKV infection (defined by arthralgia with fever or skin rash) was 62.5%. Excluding index case-patients, 22 (63%) participants with symptomatic CHIKV infection sought medical care, of which 5 (23%) were diagnosed with chikungunya and 2 (9%) were reported to PRDH.</p><p>Conclusions/Significance</p><p>This investigation revealed high rates of CHIKV infection among household members and neighbors of chikungunya patients, and that behavioral interventions such as use of air conditioning were associated with prevention of CHIKV infection. Nearly two-thirds of patients with symptomatic CHIKV infection sought medical care, of which less than one-quarter were reportedly diagnosed with chikungunya and one-in-ten were reported to public health authorities. These findings emphasize the need for point-of-care rapid diagnostic tests to optimize identification and reporting of chikungunya patients.</p></div

Demographics, pre-existing medical conditions, household characteristics, and mosquito avoidance behaviors associated with chikungunya virus infection among household-based cluster investigations participants in Puerto Rico, 2014 (N = 250).

<p>Demographics, pre-existing medical conditions, household characteristics, and mosquito avoidance behaviors associated with chikungunya virus infection among household-based cluster investigations participants in Puerto Rico, 2014 (N = 250).</p

Illness and health care seeking behaviors of household-based cluster investigation participants that reported an acute illness in the previous three months, Puerto Rico, 2014.

<p>Illness and health care seeking behaviors of household-based cluster investigation participants that reported an acute illness in the previous three months, Puerto Rico, 2014.</p

Dendrogram of hierarchical cluster analysis of symptoms among household-based cluster investigation participants that reported an acute illness in the previous three months, Puerto Rico, 2014

<p>Dendrogram of hierarchical cluster analysis of symptoms among household-based cluster investigation participants that reported an acute illness in the previous three months, Puerto Rico, 2014</p

Duration of detection of diagnostic markers of chikungunya virus infection by test and time of specimen collection post-illness-onset.

<p>Duration of detection of diagnostic markers of chikungunya virus infection by test and time of specimen collection post-illness-onset.</p