Economic impact of dengue

00000000 Few studies of the economic impact of DF and DHF/DSS have been conducted. Children most frequently suffer from DHF/DSS, with average hospital stays of 5 - 10 days for severe cases. Intensive care is required for severely ill patients, including intravenous fluids, blood or plasma transfusion and medicines, and adults can miss work in order to attend to their children's illness. Consequently, there are both direct and indirect costs for each dengue patient, ranging from inconvenience due to a sick child (or adult) with uncomplicated DF, to substantial costs for hospitalization and significant disruption of earning potential. In addition, there are costs to local municipalities for vector control activities, and often revenue lost through reduced tourism. The cost of the 1981 Cuban epidemic of DHF/DSS was estimated to be approximately US$ 103 million, which includes the cost of control measures (US$ 43 million) and medical services (US$ 41 million). As another example, DF and DHF/DSS epidemics in Puetro Rico since 1977 are estimated to have cost US$ 150 - 200 million. The direct costs that were estimated for the 1987 epidemic of DHF/DSS in Thailand, including hospitalization and mosquito control, were US$ 16 million. A 1995 report estimated that the annual economic burden due to DHF in Thailand ranges from US$ 19 million to US$ 51 million per year, depending on whether low or high levels of transmission occur. While the exact cost of each epidemic is difficult to calculate, it is clear that DF and DHF/DSS represent a significant economic burden on the societies affected.

Characteristics of dengue haemorrhagic fever outbreaks

00000000 Although the early outbreaks of DHF seem to have appeared suddenly in the Philippines and in Thailand, retrospective studies indicate that they were probably preceded by a decade or so in which cases occurred but were not recognized. In Thailand, outbreaks first occurred in Bangkok in a pattern with a 2-year cycle, then subsequently in irregular cycles as the disease spread throughout the country. DHF then became endemic in many large cities of Thailand, eventually spreading to smaller towns and villages during periods of epidemic transmission. A similar pattern was observed in Indonesia, Myanmar and Viet Nam.

00000000 During the 40 years' experience with dengue in the Western Pacific and South-East Asia Regions, two important epidemiological patterns have been recognized. First, DHF/DSS has appeared most frequently in areas where multiple dengue serotypes are endemic. The usual pattern is that of sporadic cases or small outbreaks in urban areas that steadily increase in size until there is an explosive outbreak that brings the disease to the attention of public health authorities. The disease then usually establishes a pattern of epidemic activity every 2 - 5 years. In addition, DHF/DSS is typically confined to children, with a modal age at hospitalization of 4 - 6 years. A second pattern is observed in areas of low endemicity. Multiple dengue serotypes may be transmitted at relatively low rates of infection (below 5% of the population per year). In these areas, previously uninfected adults are susceptible to dengue infection, and children and young adults, with a modal age of 6 - 8 years, are also vulnerable.
A cyclical pattern of increased transmission coinciding with the rainy season has been observed in some countries. The interactions between temperature and rainfall are important determinants of dengue transmission, as cooler temperatures affect adult mosquito survival, thus influencing transmission rates. Furthermore, rainfall and temperature may affect patterns of mosquito feeding and reproduction, and hence the population density of vector mosquitos.