Prevalence and Risk Factors of Dengue Infection in Khanh Hoa Province, Viet Nam: A Stratified Cluster Sampling Survey

Abstract

BackgroundDengue is a clinically important arthropod-borne viral disease with increasing global incidence. Here we aimed to estimate the prevalence of dengue infections in Khanh Hoa Province, central Viet Nam, and to identify risk factors for infection.MethodsWe performed a stratified cluster sampling survey including residents of 3–60 years of age in Nha Trang City, Ninh Hoa District and Dien Khanh District, Khanh Hoa Province, in October 2011. Immunoglobulin G (IgG) and immunoglobulin M (IgM) against dengue were analyzed using a rapid test kit. Participants completed a questionnaire exploring clinical dengue incidence, socio-economic status, and individual behavior. A household checklist was used to examine environment, mosquito larvae presence, and exposure to public health interventions.ResultsIgG positivity was 20.5% (urban, 16.3%; rural, 23.0%), IgM positivity was 6.7% (urban, 6.4%; rural, 6.9%), and incidence of clinically compatible dengue during the prior 3 months was 2.8 per 1,000 persons (urban, 1.7; rural, 3.4). For IgG positivity, the adjusted odds ratio (AOR) was 2.68 (95% confidence interval [CI], 1.24–5.81) for mosquito larvae presence in water pooled in old tires and was 3.09 (95% CI, 1.75–5.46) for proximity to a densely inhabited area. For IgM positivity, the AOR was 3.06 (95% CI, 1.50–6.23) for proximity to a densely inhabited area.ConclusionsOur results indicated rural penetration of dengue infections. Control measures should target densely inhabited areas, and may include clean-up of discarded tires and water-collecting waste.

Seroprevalence and associated risk factors of Dengue fever in Kassala state, eastern Sudan

“…Unlike our study, another study in Kassala showed strong associations between dengue circulation and lack of knowledge about dengue disease and household density of more than 3 people per room [37]. A recent study in Vietnam showed a strong association between dengue infection and dengue education, the presence of mosquito larvae in old tires containing water, and proximity to a densely inhabited area [39]. Siregar and colleagues [57] found that history of the previous infection of dengue hemorrhagic fever in the family was one of the risk factors, similar to our observations in the present study.…”

“…The increased seroprevalence may be influenced by active circulation and repeated outbreaks of dengue infections in Kassala state [ 26 ]. Many studies have reported the seroprevalence of dengue using diverse serological assays in diverse endemic sites, for example, haemagglutination inhibition in Venezuela [ 38 ], ELISA in Vietnam and Sudan [ 39 , 40 ]. Other tests used in previous studies in Sudan include RAPID-cassette test in Port Sudan [ 41 ], ELISA in Kassala [ 28 , 29 , 31 ], ELISA and real-time PCR in Kassala [ 42 ], ELISA in Gedarif [ 43 ].…”

Retrospective cross-sectional observational study on the epidemiological profile of dengue cases in Pernambuco state, Brazil, between 2015 and 2017

“…Among the intermediate regions of Pernambuco, Recife and Caruaru had the highest number of cases and the highest dengue incidence per 100 thousand inhabitants; a scenario possibly influenced by environmental factors, mainly climatic conditions, which strongly modulate the population of vector mosquitoes [15,17,[19][20][21][22][23][24][25][26]. The Pernambuco state, however, located in the tropical region of Brazil, precisely between the Equator and the Tropic of Cancer, is marked by constant temperatures, as evidenced by our temperature analysis of the four intermediate regions over the 3 years.…”

“…In relation to environmental factors, uncontrolled urbanization and climatic conditions, such as temperature and rainfall, capable of influencing the population of vector mosquitoes, mainly Aedes aegypti and Ae. albopictus, are some of the elements that contribute to the incidence of dengue [16][17][18][19][20][21][22][23][24][25][26]. Interestingly, the association between climatic factors and mosquito-borne infectious diseases, such as dengue and Zika, has also been demonstrated through information extracted from newspapers [27,28].…”

Impact of Climate Variability and Abundance of Mosquitoes on Dengue Transmission in Central Vietnam

“…Most dengue studies conducted in Vietnam focused on the northern area (Hanoi) and southern regions [34,[37][38][39]. The central region of Vietnam is also an endemic area for dengue; however, there is little relevant research in this region [40,41]. Therefore, dengue transmission dynamics and relevant environmental risk factors in central Vietnam are not understood.This study aimed to fill the knowledge gap concerning dengue transmission in central Vietnam by investigating the spatiotemporal distributions of dengue outbreaks and evaluating the impact of climate and the vector index on dengue transmission in this region.…”