ABSTRACT
Objective:To analyze the largest outbreak of dengue in Argentina in the municipality of Tigre during 2016, through detailed spatial analyses of the occurrence of cases in relation to demographic factors and vector control actions.Methods:Detailed and georreferenced data on dengue cases with laboratory results (NS1 or IgM) were analyzed. The occurrences of imported and autochthonous cases by census tract were modeled using demographic variables (population by age class, proportion of foreigners, proportion with university grade, proportion of males), dwelling variables (number of homes, proportion of dwellings with latrine, number of dwellings, proportion of houses, proportion of flats, proportion of slums) and census tract area as explanatory variables. The probability of occurrence of autochthonous and imported cases was modeled separately. The spatio-temporal occurrence of cases was studied in relation to focal and perifocal control actions (involving education campaigns, removal of Aedes aegypti breeding sites and exhaustive insecticide spraying) to assess the efficiency in stopping autochthonous cases spreading.Results:All autochthonous cases occurred in the urban environment with no sylvan cases. The majority of the imported cases registered came from Paraguay and Northeastern Argentina. The age structure of imported and autochthonous cases did not differ from the age structure of the municipality, while that of the negative cases did. When studied spatially, the occurrence of imported cases by census tract was mildly associated with a higher proportion of foreign population and more people at active age, while occurrence of autochthonous cases was not significantly associated with any of the studied variables. For census tracts with laboratory confirmed results, the models showed higher probability of autochthonous cases related to higher population density and population age structure. The clustering of autochthonous cases was generally mild, with prevailing isolated cases and a weak spread inside the municipality. The biggest outbreak focus was associated with a delay in the focal vector control.Conclusions:Results confirmed the virus pressure coming from neighboring countries and related to population movement by workers. All autochthonous cases occurred in the urban environment with no sylvan cases. The susceptibility of residents to dengue may be similar among age classes and the laboratory tests were performed more frequently in the younger. Autochthonous cases incidence was low and spatio-temporal clustering of cases weak, suggesting that control measures were effective when no delay occurred in their application.
ABSTRACT
Objective: To analyze the largest outbreak of dengue in Argentina in the municipality of Tigre during 2016, through detailed spatial analyses of the occurrence of cases in relation to demographic factors and vector control actions. Methods: Detailed and georreferenced data on dengue cases with laboratory results (NS1 or IgM) were analyzed. The occurrences of imported and autochthonous cases by census tract were modeled using demographic variables (population by age class, proportion of foreigners, proportion with university grade, proportion of males), dwelling variables (number of homes, proportion of dwellings with latrine, number of dwellings, proportion of houses, proportion of flats, proportion of slums) and census tract area as explanatory variables. The probability of occurrence of autochthonous and imported cases was modeled separately. The spatio-temporal occurrence of cases was studied in relation to focal and perifocal control actions (involving education campaigns, removal of Aedes aegypti breeding sites and exhaustive insecticide spraying) to assess the efficiency in stopping autochthonous cases spreading. Results: All autochthonous cases occurred in the urban environment with no sylvan cases. The majority of the imported cases registered came from Paraguay and Northeastern Argentina. The age structure of imported and autochthonous cases did not differ from the age structure of the municipality, while that of the negative cases did. When studied spatially, the occurrence of imported cases by census tract was mildly associated with a higher proportion of foreign population and more people at active age, while occurrence of autochthonous cases was not significantly associated with any of the studied variables. For census tracts with laboratory confirmed results, the models showed higher probability of autochthonous cases related to higher population density and population age structure. The clustering of autochthonous cases was generally mild, with prevailing isolated cases and a weak spread inside the municipality. The biggest outbreak focus was associated with a delay in the focal vector control. Conclusions: Results confirmed the virus pressure coming from neighboring countries and related to population movement by workers. All autochthonous cases occurred in the urban environment with no sylvan cases. The susceptibility of residents to dengue may be similar among age classes and the laboratory tests were performed more frequently in the younger. Autochthonous cases incidence was low and spatio-temporal clustering of cases weak, suggesting that control measures were effective when no delay occurred in their application.
ABSTRACT
Dengue is a leading public health problem in Sri Lanka. All 26 districts and all age groups are affected, with high disease transmission; the estimated average annual incidence is 175/100 000 population. Harnessing the World Health Organization Global strategy for dengue prevention and control, 2012–2020, Sri Lanka has pledged in its National Strategic Framework to achieve a mortality from dengue below 0.1% and to reduce morbidity by 50% (from the average of the last 5 years) by 2020. Turning points in the country’s dengue-control programme have been the restructuring and restrategizing of the core functions; this has involved establishment of a separate dengue-control unit to coordinate integrated vector management, and creation of a presidential task force. There has been great progress in disease surveillance, clinical management and vector control. Enhanced real-time surveillance for early warning allows ample preparedness for an outbreak. National guidelines with enhanced diagnostics have significantly improved clinical management of dengue, reducing the case-fatality rate to 0.2%. Proactive integrated vector management, with multisector partnership, has created a positive vector-control environment; however, sustaining this momentum is a challenge. Robust surveillance, evidence-based clinical management, sustainable vector control and effective communication are key strategies that will be implemented to achieve set targets. Improved early detection and a standardized treatment protocol with enhanced diagnostics at all medical care institutions will lead to further reduction in mortality. Making the maximum effort to minimize outbreaks through sustainable vector control in the three dimensions of risk mapping, innovation and risk modification will enable a reduction in morbidity.