Dengue virusClimate changes might play an important role in sustaining the transmission cycle between vectors and human hosts and the spread of transmission.

Weather

7. 8. 9 月

For assessing the health effects of climate change, these large scale models had adopted general circulation models (GCMs) in predicting climate change scenarios to result in a projection for longer time period and expanded global geographical areas of intensive dengue fever transmission.

Many site-specific differences in those factors affecting disease transmission, such as mosquito density and immunity status, could not be adequately assessed in any large-scale prediction models for the often-low geographical resolutions in data of both weather parameters and disease incidence.

A more localized and comprehensive analysis by using site-specific data is therefore more applicable to design

an early warning and disease prevention program.

Taiwan

Time-seriesWeather variability vs. Dengue fever

the Center for Disease Control Taiwan

Study area

46.3% of total dengue fever cases

Subtropical region

Tropical region

台南市 100%台南縣 48%高雄縣市 100%屏東縣 64%

6% 台東縣

Taiwan is located in both subtropical and tropical regions with relatively high temperature and relative humidity year-round, which are ideal conditions for the dissemination and growth of the vector of dengue fever—mosquito.

the Center for Disease Control Taiwan

Study area

46.3% of total dengue fever cases

2–9 imported cases notified annually in Kaohsuing City Warmer winter and in less humid months

Quantitation of effect of several stimuli on landing and probing by Aedes aegypti, Khan, A.A. et al J. Econ. Entomol. 1967

Weather variables were significantly associated with incidence rate of dengue fever using cross-correlations.

ARIMA

auto-regressive integrated moving average

Fig. 3. The actual incidence rate and predicted incidence rate by auto-regressive integrated moving average (ARIMA) model of weather variation in Kaohsiung City, Taiwan.

The predicted values and actual incidence rate matched very well, and when cross-comparison with the actual historical records, these identified peaks were exactly the years and months when the outbreak was reported to our registry system.

The past global prediction model could not accurately predict the actual impacts in Taiwan for only using 2 grid data to represent the weather variations in Taiwan.

General circulation models (GCMs)

The ultimate importance in establishing a site-specific model for future prediction in the actual risk of diseases occurrence.

• Climate change and health: global to local influences on disease risk Patz, J.A. and Olson, S.H. Annals of Tropical Medicine and Parasitology, 2006.

The World Health Organization has concluded that the climatic changes that have occurred since the mid 1970s could already be causing annually over 150,000 deaths and five million disability-adjusted life-years (DALY), mainly in developing countries. The less developed countries are, ironically, those least responsible for causing global warming. Many health outcomes and diseases are sensitive to climate, including: heat-related mortality or morbidity; air pollution-related illnesses; infectious diseases, particularly those transmitted, indirectly, via water or by insect or rodent vectors; and refugee health issues linked to forced population migration. Yet, changing landscapes can significantly affect local weather more acutely than long-term climate change. Land-cover change can influence micro-climatic conditions, including temperature, evapo-transpiration and surface run-off, that are key determinants in the emergence of many infectious diseases. To improve risk assessment and risk management of these synergistic processes (climate and land-use change), more collaborative efforts in research, training and policy-decision support, across the fields of health, environment, sociology and economics, are required.

Overall increasing temperature in different regions of the world might allow these vectors to survive over winter and help to extend into regions previously free of disease or exacerbation of transmission in endemic regions and also change the transmis

sion season.

Thanks for your attention

General circulation model :A general circulation model (also known as a global climate model, both labels are abbreviated as GCM) uses the same equations of motion as a numerical weather prediction (NWP) model, but the purpose is to numerically simulate changes in climate as a result of slow changes in some boundary conditions (such as the solar constant) or physical parameters (such as the greenhouse gas concentration).