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First dengue virus seroprevalence study on Madeira Island after the 2012 outbreak indicates unreported dengue circulation.

ABSTRACT: BACKGROUND:In 2012, the first dengue virus outbreak was reported on the Portuguese island of Madeira with 1080 confirmed cases. Dengue virus of serotype 1 (DENV-1), probably imported from Venezuela, caused this outbreak with autochthonous transmission by invasive Aedes aegypti mosquitoes. RESULTS:We investigated the seroprevalence among the population on Madeira Island four years after the outbreak. Study participants (n?=?358), representative of the island population regarding their age and gender, were enrolled in 2012 in a cross-sectional study. Dengue antibodies were detected with an in-house enzyme-linked immunosorbent assay (ELISA) using the dimer of domain III (ED3) of the DENV-1 envelope protein as well as commercial Panbio indirect and capture IgG ELISAs. Positive ELISA results were validated with a neutralization test. The overall seroprevalence was found to be 7.8% (28/358) with the in-house ELISA, whereas the commercial DENV indirect ELISA detected IgG antibodies in 8.9% of the individuals (32/358). The results of the foci reduction neutralization test confirmed DENV-1 imported from South America as the causative agent of the 2012 epidemic. Additionally, we found a higher seroprevalence in study participants with an age above 60 years old and probable secondary DENV infected individuals indicating unreported dengue circulation before or after 2012 on Madeira Island. CONCLUSIONS:This study revealed that the number of infections might have been much higher than estimated from only confirmed cases in 2012/2013. These mainly DENV-1 immune individuals are not protected from a secondary DENV infection and the majority of the population of Madeira Island is still naïve for DENV. Surveillance of mosquitoes and arboviruses should be continued on Madeira Island as well as in other European areas where invasive vector mosquitoes are present.

SUBMITTER: Auerswald H

PROVIDER: S-EPMC6417143 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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First dengue virus seroprevalence study on Madeira Island after the 2012 outbreak indicates unreported dengue circulation.

Auerswald Heidi H de Jesus Ana A Seixas Gonçalo G Nazareth Teresa T In Saraden S Mao Sokthearom S Duong Veasna V Silva Ana Clara AC Paul Richard R Dussart Philippe P Sousa Carla Alexandra CA

Parasites & vectors 20190313 1

<h4>Background</h4>In 2012, the first dengue virus outbreak was reported on the Portuguese island of Madeira with 1080 confirmed cases. Dengue virus of serotype 1 (DENV-1), probably imported from Venezuela, caused this outbreak with autochthonous transmission by invasive Aedes aegypti mosquitoes.<h4>Results</h4>We investigated the seroprevalence among the population on Madeira Island four years after the outbreak. Study participants (n = 358), representative of the island population regarding th ...[more]

PMID: 30867031

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Project description:The ability to effectively modify behaviours is increasingly relevant to attain and maintain a good health status. Current behaviour-change models and theories present two main approaches for (healthier) decision-making: one analytical/logical, and one experiential/emotional/intuitive. Therefore, to achieve an integral and dynamic understanding of the public perceptions both approaches should be considered: community surveys should measure cognitive understanding of health-risk contexts, and also explore how past experiences affect this understanding. In 2011, community perceptions regarding domestic source reduction were assessed in Madeira Island?. After Madeira's first dengue outbreak (2012) a unique opportunity to compare perceptions before and after the outbreak-experience occurred. This was the aim of this study, which constituted the first report on the effect of an outbreak experience on community perceptions regarding a specific vector-borne disease. A cross-sectional survey was performed within female residents at the most aegypti-infested areas. Perceptions regarding domestic source reduction were assessed according to the Essential Perception (EP)-analysis tool. A matching process paired individuals from studies performed before and after the outbreak, ensuring homogeneity in six determinant variables. After the outbreak, there were more female residents who assimilated the concepts considered to be essential to understand the proposed behaviour. Nevertheless, no significant difference was observed in the number of female residents who achieved the defined 'minimal understanding''. Moreover, most of the population (95.5%) still believed at least in one of the identified myths. After the outbreak some myths disappeared and others appeared. The present study quantified and explored how the experience of an outbreak influenced the perception regarding a dengue-preventive behaviour. The outbreak experience surprisingly led to the appearance of new myths within the population, apart from the expected increase of relevant concepts' assimilation. Monitoring public perceptions is therefore crucial to make preventing dengue campaigns updated and worthy.

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First dengue virus seroprevalence study on Madeira Island after the 2012 outbreak indicates unreported dengue circulation.

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First dengue virus seroprevalence study on Madeira Island after the 2012 outbreak indicates unreported dengue circulation.

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