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Title: Epidemiology and spatial-temporal distribution of dengue in Vietnam
Author: Hoang, Quoc Cuong
ISNI:       0000 0004 5991 9302
Awarding Body: Open University
Current Institution: Open University
Date of Award: 2016
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Vietnam, a tropical country in Southeast Asia, has been dengue endemic since 1958. Dengue poses a major public health concern and economic burden to Vietnam, with average incidence of more than one hundred thousand cases, annually. Dengue epidemiology is complex and a result of interactions between the host, the virus, the vector and environmental factors. This thesis sought to investigate and define the spatial and temporal transmission patterns of dengue in order to support planning allocation of resources to better control and predict the seasonal epidemics. Increases in reported dengue incidence over the past decade suggest that dengue is an emerging problem in Hanoi, the capital of Vietnam. We found that districts in the central, highly urbanized area of Hanoi are at highest risk of dengue (Standardized Morbidity Ratio >3). Rainfall and temperature correlated positively with dengue incidence, while wind velocity correlated negatively. In Ho Chi Minh City (HCMC), the per capita incidence of dengue was lower than in most southern provinces and annual epidemics occurred 1-3 months later than elsewhere. Both the timing and the magnitude of annual epidemics were significantly more correlated in districts at closer proximity, suggesting local drivers operating at a scale of 50-100km. Using a simple linear model we showed that dengue incidence during the dry season accounted for 63% of variability in rainy season epidemic magnitude. Finally, we examined spatial patterns of case and serotypes distribution of dengue in HCMC in comparison to Bangkok, Thailand. We found that annual case numbers were highly consistent across the two cities (correlation of 0.77,95% Cl 0.74-0.79) as was the annual force of infection (correlation of 0.57, 95% Cl 0.46-0.68). Serotypes were far less similar with serotype-specific correlations ranging from 0.65 for DENV1 to -0.14 for DENV4. Significant spatial clustering of serotypes was observed in HCMC at distances <500m, similar to observations from Bangkok. These data suggest similar overall mechanisms determine the epidemiology of dengue in these two major urban centres. Collectively the findings in this thesis might aid the targeting of vector-control interventions, the planning for dengue vaccine implementation and/or epidemic prediction.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available