Dengue Virus Infections among Haitian and Expatriate Non-governmental Organization Workers — Léogane and Port-au-Prince, Haiti, 2012

<div><p>In October 2012, the Haitian Ministry of Health and the US CDC were notified of 25 recent dengue cases, confirmed by rapid diagnostic tests (RDTs), among non-governmental organization (NGO) workers. We conducted a serosurvey among NGO workers in Léogane and Port-au-Prince to determine the extent of and risk factors for dengue virus infection. Of the total 776 staff from targeted NGOs in Léogane and Port-au-Prince, 173 (22%; 52 expatriates and 121 Haitians) participated. Anti-dengue virus (DENV) IgM antibody was detected in 8 (15%) expatriates and 9 (7%) Haitians, and DENV non-structural protein 1 in one expatriate. Anti-DENV IgG antibody was detected in 162 (94%) participants (79% of expatriates; 100% of Haitians), and confirmed by microneutralization testing as DENV-specific in 17/34 (50%) expatriates and 42/42 (100%) Haitians. Of 254 pupae collected from 68 containers, 65% were <i>Aedes aegypti</i>; 27% were <i>Ae. albopictus</i>. Few NGO workers reported undertaking mosquito-avoidance action. Our findings underscore the risk of dengue in expatriate workers in Haiti and Haitians themselves.</p></div

Dengue diagnostic test results of non-governmental organization workers living in Léogane and Port-au-Prince, Haiti, 2012.^*

<p>*DENV denotes dengue virus. NS1 denotes the DENV non-structural protein 1. ELISA denotes an enzyme-linked immunosorbent assay.</p>†<p>p-value was calculated using a 2-tailed Fisher's exact test.</p>‡<p>Positive by DENV-1–4 Real-Time rt-PCR.</p>§<p>Positive by the NS1antigen capture ELISA.</p>¶<p>Positive by the DENV Detect immunoglobulin M Capture ELISA.</p>#<p>Positive by an anti-dengue virus immunoglobulin G ELISA. All expatriate and 40 Haitian samples that were IgG ELISA positive received confirmatory testing by microneutralization.</p><p>Dengue diagnostic test results of non-governmental organization workers living in Léogane and Port-au-Prince, Haiti, 2012.^{<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003269#nt107" target="_blank">*</a>}</p

Risk factors for current and/or recent dengue virus (DENV) infection in non-governmental organization (NGO) workers living in Léogane and Port-au-Prince, Haiti, 2012.

<p>*OR, odds ratio.</p>†<p>Recent infection is any participant with a positive anti-DENV IgM or non-structural protein 1 (NS1) result.</p>‡<p>Significance level, p<0.05. Univariate analysis using Fisher's exact test was used to assess risk factors for recent infection, and 95% confidence intervals (CI) were based on the modeling accounted for the sampling design. Only significant variables with a cell size of 5 or greater were retained.</p><p>Risk factors for current and/or recent dengue virus (DENV) infection in non-governmental organization (NGO) workers living in Léogane and Port-au-Prince, Haiti, 2012.</p

Results from the entomological survey conducted in Léogane, Haiti, December 5–13, 2012.

<p>*Entomologic surveys conducted at all NGO worksites and NGO residences included surveys of adjacent buildings. Adjacent buildings were not surveyed for Haitian employee residences.</p><p>Premise index = the percentage of premises infested with immature mosquitoes.</p><p>Container index = the percentage of water-holding containers with immature mosquitoes.</p><p>Breteau index = the number of containers with immature mosquitoes per 100 premises.</p><p>Results from the entomological survey conducted in Léogane, Haiti, December 5–13, 2012.</p

Location of non-governmental organizations that participated in dengue serosurvey, Haiti, 2012.

<p>Location of non-governmental organizations that participated in dengue serosurvey, Haiti, 2012.</p

Demographics, travel history, and vaccination and clinical history of non-governmental organization workers living in Léogane and Port-au-Prince, Haiti, 2012.

<p>* p-value was calculated using a 2-tailed Fisher's exact test; the p-value for age and work site was calculated using Chi square with Yate's correction.</p>†<p>10 Haitians and 2 expatriates did not report their age.</p>‡<p>5 Haitians and 1 expatriate did not report their occupation.</p>§<p>includes people who knew about their recent diagnosis (within the last 90 days).</p><p>Demographics, travel history, and vaccination and clinical history of non-governmental organization workers living in Léogane and Port-au-Prince, Haiti, 2012.</p

Confirmation of anti-DENV IgG positive ELISA results, Haiti, 2012.

<p>*42 specimens were randomly selected from the 121 IgG-positive Haitians (95% confidence interval [CI]: 94.5%–100%).</p>†<p>Samples that were anti-IGM ELISA positive were not tested by microneutralization since they were considered recent DENV infections.</p><p>** DENV cross reactive = positive neutralization titers to more than one DENV serotype without a four-fold difference between DENV serotypes to determine the predominant serotype; Primary DENV = reactivity to only one DENV serotype.</p><p>Confirmation of anti-DENV IgG positive ELISA results, Haiti, 2012.</p

Dengue knowledge, mosquito avoidance strategies and personal protective measures of non-governmental organization workers living in Léogane and Port-au-Prince, Haiti, 2012.

<p>*p-value was calculated using a 2-tailed Fisher's exact test.</p>†<p>all percentages were rounded to the nearest whole number.</p><p>Dengue knowledge, mosquito avoidance strategies and personal protective measures of non-governmental organization workers living in Léogane and Port-au-Prince, Haiti, 2012.</p