Conditions of the household and peridomicile and severe dengue: a case–control study in Brazil

Abstract

IntroductionThe potential influence of high-vector-density environments where people are supposedly more exposed to mosquito bites may have a relation to the clinical severity of dengue fever, an association that has been poorly discussed in the literature.ObjectiveThis study aimed at analyzing the association between anthropic environmental factors, particularly those related to the conditions of domicile and peridomicile, and the occurrence of severe dengue cases during the 2008 epidemic in the state of Rio de Janeiro.MethodsWe conducted a retrospective case–control study with a sample of 88 severe patients aged 2–18. They were selected through chart review in four children's tertiary care centers. The 367 controls were neighbors of the cases, paired by age. Data were collected through interviews and systematic assessment of house conditions as well as peridomicile area conditions, and they were later analyzed by conditional logistic regression.ResultsThe presence of three or more high-volume capacity containers, which were without a lid or were inadequately sealed (water tanks, wells, cisterns, cement tanks, and pools), was significantly more frequent in households with severe cases when compared with households of controls (OR=1.6; CI 95%=1.36–20.01; p=0.015).DiscussionThe presence of such larger reservoirs that could potentially produce more adult forms of the vector is consistent with a situation where people are more exposed to mosquito bites, and consequently are more prone to have multiple infections over a short period of time.ConclusionThe emergence of severe dengue cases in a high-transmission context underpins the importance of constant vigilance and interventions in those types of reservoirs, which result from precarious household structures and irregular water supply services.

Complex relationships between Aedes vectors, socio-economics and dengue transmission—Lessons learned from a case-control study in northeastern Thailand

“…This might explain the higher risk of dengue for individuals working indoors suggested in the current study. In contrast to other studies [ 61 , 62 ], our results suggested that traveling outside the resident district during the previous three months was negatively associated with dengue risk ( Table 1 ). Studies in Thailand have shown that dengue incidence is commonly spatially clustered [ 63 , 64 ] and infection risk can be highly focal; thus moving out of the study areas might have exposed travelers to differential risks (higher or lower) of dengue transmission.…”

“…Most dengue case-control studies focused on the epidemiological risk factors associated with higher severity of dengue disease, while fewer have investigated the role of entomological factors. Moreover, the majority of those studies used immature Aedes indices to assess the infestation level (density) in the study area [ 61 , 62 ]. Nevertheless, a study in Sao Paulo, Brazil demonstrated a strong association between numbers of female Aedes collected over a fortnight and dengue incidence [ 89 ].…”

A populational-based birth cohort study in a low-income urban area in Rio de Janeiro, Brazil: implementation and description of the characteristics of the study

“…The presence of water reservoirs inside the households results in potential breeding sites and contributes to stable mosquito infestation over time 30,31 . As expected, mosquitoes collection in keysites and daycare facilities were more effective than in the households 30 . In almost all households in which a febrile case dwelt, the Aedes spp.…”

Molecular and clinical epidemiological surveillance of dengue virus in Paraíba, Northeast Brazil

“…Although there were low numbers of DCC, DWS, and DHF, there was a slight increase in the proportion of these cases from 2010. The increase in severe dengue cases may have been associated with the reintroduction of a different serotype 28 .…”