Incidence of dengue illness in Mexican people aged 6 months to 50 years old: A prospective cohort study conducted in Jalisco

Abstract

Background and objectives: The burden of dengue virus (DENV), a mosquito-borne pathogen, remains difficult to assess due to misdiagnosis and underreporting. Moreover, the large proportion of asymptomatic dengue cases impairs comprehensive assessment of its epidemiology even where effective surveillance systems are in place. We conducted a prospective community-based study to assess the incidence of symptomatic dengue cases in Zapopan and neighboring municipalities in the state of Jalisco, Mexico.

Methods: Healthy subjects aged 6 months to 50 years living in households located in the Zapopan and neighboring municipalities were enrolled for a 24-month follow-up study (NCT02766088). Serostatus was determined at enrolment and weekly contacts were conducted via phone calls and home visits. Participants had to report any febrile episode lasting for at least two days. Suspected dengue cases were tested by reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR), detection of non-structural protein 1 (NS1), anti-DENV immunoglobulin G and M (IgG and IgM) assays.

Results: A total of 350 individuals from 87 households were enrolled. The overall seroprevalence of anti-DENV IgG at enrolment was 19.4% (95% confidence interval [CI] 14.5-25.6) with the highest seroprevalence rate observed in the adult group. Over the 27-month study period from July 2016 to September 2018, a total of 18 suspected dengue cases were reported. Four cases were confirmed by RT-qPCR and serotyped as DENV-1. A fifth case was confirmed by the NS1 assay. The 13 remaining suspected cases were tested negative by these assays. Based on the 5 virologically confirmed cases, symptomatic dengue incidence proportion of 1.4% (95%CI 0.5-3.8) was estimated. No severe cases or hospitalizations occurred during the study.

Conclusion: Community-based active surveillance was shown as efficient to detect symptomatic dengue cases.

Clinical trial registration: NCT02766088.

Conflict of interest statement

GlaxoSmithKline Biologicals SA (GSK) funded this study and covered all costs associated with the development and publication of this manuscript. GH, SD, MDB and AG are employees of the GSK group of companies. SD and AG hold shares in the GSK group of companies. RD was an employee of the GSK group of companies at the time of the study. GAT received payments from the GSK group of companies, as part of the multi-center study. GH, SD, MDB, AG and GAT declare no other financial and nonfinancial relationships and activities. GIN declare no financial and non-financial relationships and activities and no conflicts of interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials, but please note that the anonymized data is only available upon request due to privacy reasons regarding patient’s privacy and sensitive data.

Figures

Fig 1. Study design.

SAE, serious adverse event related to blood drawn. Virologically confirmed dengue case: confirmed by reverse-transcriptase quantitative polymerase chain reaction or detection of non-structural protein 1 antigen.

Fig 2. Plain language summary.