Twenty years of Dengue surveillance at a ministry of health hospital in Kamphaeng Phet, Thailand, 1994-2013

Dengue virus (DENV) is a vector-borne viral disease transmitted by the Aedes aegypti and Aedes albopictus mosquitos. The majority of dengue cases present as asymptomatic to mild febrile illness. Only a small percentage of cases manifest more severe symptoms. Currently, dengue is endemic in over 100 countries, and five different continents, making about 40% of the world’s population at risk for dengue transmission. This represents a global public health risk. Long-term observational studies provide valuable insights into overall dengue epidemiology. This paper presents an analysis of dengue cases presenting to a Ministry of Health provincial hospital in Kamphaeng Phet, Thailand during the twenty-year period from 1994-2013. Data was analyzed from 12,200 hospitalized patients with suspected DENV infection and confirmed by Nested PCR and enzyme-linked immunosorbent assay (ELISA). Exploratory data analysis was performed and several long-term trends of dengue disease were identified. Chief among those findings was an increase in mean age for both primary and secondary infections. Co-circulation of multiple serotypes in multiple years was also found. Thailand is an important setting for studying DENV transmission due to the hyper endemic status of dengue, and the presence of a strong surveillance. Further research within Thailand is needed to continue to understand the relationship between geography and dengue incidence. These results may increase understanding of dengue in other countries with similar changes in transmission and population demographics that may now or soon be occurring