A household serosurvey to estimate the magnitude of a dengue outbreak in Mombasa, Kenya, 2013.

Dengue appears to be endemic in Africa with a number of reported outbreaks. In February 2013, several individuals with dengue-like illnesses and negative malaria blood smears were identified in Mombasa, Kenya. Dengue was laboratory confirmed and an investigation was conducted to estimate the magnitude of local transmission including a serologic survey to determine incident dengue virus (DENV) infections. Consenting household members provided serum and were questioned regarding exposures and medical history. RT-PCR was used to identify current DENV infections and IgM anti-DENV ELISA to identify recent infections. Of 1,500 participants from 701 households, 210 (13%) had evidence of current or recent DENV infection. Among those infected, 93 (44%) reported fever in the past month. Most (68, 73%) febrile infected participants were seen by a clinician and all but one of 32 participants who reportedly received a diagnosis were clinically diagnosed as having malaria. Having open windows at night (OR = 2.3; CI: 1.1-4.8), not using daily mosquito repellent (OR = 1.6; CI: 1.0-2.8), and recent travel outside of Kenya (OR = 2.5; CI: 1.1-5.4) were associated with increased risk of DENV infection. This survey provided a robust measure of incident DENV infections in a setting where cases were often unrecognized and misdiagnosed

Epidemiological curve of 267 suspected dengue cases detected at hospitals from January–May, 2013, of which 155 (58%) were confirmed to have a current DENV infection and included a single fatal case.

<p>Epidemiological curve of 267 suspected dengue cases detected at hospitals from January–May, 2013, of which 155 (58%) were confirmed to have a current DENV infection and included a single fatal case.</p

Demographic characteristics, symptoms and medical outcomes reported by 1,500 residents of Tudor, Mombasa, participating in serologic survey for dengue virus infection (DENV), April through May 2013.

<p>* Bleeding manifestations included nose bleeding, bleeding from gums, blood in vomitus, blood in urine, blood in stool, or heavy vaginal bleeding.</p><p>Demographic characteristics, symptoms and medical outcomes reported by 1,500 residents of Tudor, Mombasa, participating in serologic survey for dengue virus infection (DENV), April through May 2013.</p

Map of 210 dengue virus (DENV) infected participants in Tudor, Mombasa, Kenya.

<p>Participants with evidence of current or recent DENV infection were distributed throughout the Tudor district, and there was no statistically significant clustering by area. Solid black circles represent IgM anti-DENV positive participants, white circles represent RT-PCR positive participants.</p

Risk factors associated with dengue virus infections (DENV) among residents of Tudor, Mombasa, Kenya, May 2013.

<p>* Weighted percentages are reported, reflecting the stratified sampling design. Responses were weighted to account for the different probabilities of household inclusion across strata, within-household participation rates, and inter-household clustering of infections.</p><p>** Significance level, p = 0.05. Weighted logistic regression models were used to assess risk factors for recent or current infections, and CIs were based on the modeling accounted for the sampling design. Breeding containers queried included potted plants, vegetation, wells, septic tanks, trash, buckets, water cisterns, fountains, old tires, water storage tank without lids.</p><p>Risk factors associated with dengue virus infections (DENV) among residents of Tudor, Mombasa, Kenya, May 2013.</p