DENGUE INFECTION IN PUERTO MALDONADO, PERU: HUMAN MIGRATION AND ECONOMIC IMPACT
Salmon Mulanovich, Gabriela
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Dengue virus (DENV) is an arbovirus with global distribution that affects more than 100 countries worldwide. This Flavivirus was reintroduced to Peru in the 1990s and has disseminated across several areas in the country, especially in the urban centers of the Amazon Basin. In Peru, the virus is transmitted by an anthropophilic mosquito, Aedes aegypti. Dengue has been increasing in the southern Peruvian city of Puerto Maldonado since 2000, when it was first reported there. This region has the highest human migration rate in the country, and incomers to the city are mainly from non-endemic areas for DENV. The unique migratory movement situation of this city may pose a differential risk for between recent migrants (RM) and long-term residents (LTR). In this scenario, this study was designed to a) describe the seroprevalence of dengue infection among residents of Puerto Maldonado and evaluate the influence that migration history and knowledge, attitudes and practices (KAP) related to dengue control and prevention may have on serostatus for DENV, b) to identify spatial patterns of risk for DENV infection for residents in Puerto Maldonado, considering migration background, services and infrastructure, socioeconomic status and to assess the proportion of household income that is diverted to costs incurred due to dengue illness and to compare these expenses between RM and LTR, defined respectively as residency in Puerto Maldonado for less than or greater than 5 years. A secondary objective was to describe the demographic and socioeconomic characteristics of RM and LTR in Puerto Maldonado. To achieve this we conducted a cross-sectional serosurvey and administered a KAP questionnaire to members of randomly selected households, 2012. Sera were screened for antibody to DENV by ELISA and confirmed by plaque reduction neutralization test (PRNT). We also measured other socioeconomic variables and income. To assess the household income diverted to dengue expenses we administered a standardized questionnaire to persons diagnosed with dengue disease. We compared costs incurred between RM and LTR. In order to evaluate the spatial patterns of DENV infection collected the information and geographic location where the serosurvey and questionnaire were administered. We explored the data for clustering patterns, identified clusters and tested the distance of some features in the city with DENV infection. The results of this study showed a seroprevalence of 54% (95% CI: 49.6; 58.5), which was similar among RM and LTR. RM comprised 11% of this study population. Multivariate analysis indicated that higher values of KAPi (p=0.020) and household monthly income (p=0.009) were associated with antibody positivity, while migration status remained non-significant. For our findings regarding DENV expenses, twenty-eight of the 80 participants (35%), were RM. Each dengue disease episode cost the household an average of US$ 105 (SD=107), representing 24% of their monthly income. Indirect costs were the greatest expense (US$ 56, SD=87), especially lost wages. The outcomes from spatial pattern analysis broadened the perspective of DENV infection in this city. We located areas where DENV infection clustered. As before, higher income and KAP score were predictors of infection, but the distance of the households to flooding areas was negatively associated to DENV prevalence. Therefore, with each meter away from these areas the prevalence decreased about 1% (OR: 0.999; 95% CI: 0.998; 0.999). From the serosurvey study, we concluded that the seroprevalence of DENV showed an association with risk behaviors and socio-economic status. The rather uncommon lower seroprevalence that is portrayed in Puerto Maldonado, as compared with other Peruvian cities like Iquitos, in Loreto, is likely due to the relative recent emergence of DENV in the city. Nonetheless, when exploring further the findings of this study with the spatial patterns, we were able to determine areas of higher risk in the urban area. In contrast, costs did not differ significantly between RM and LTR households. However, the study did highlight the significant financial burden incurred by households when a family member suffers dengue disease. Despite the limitations of this study, such as the lack of longitudinal information or entomological data, these findings can help guide DENV transmission prevention and vector control. Especially since this re-emergent virus is becoming a global concern and the efforts to develop an efficient vaccine continue.