This summer, many places around the world have experienced scorching heat, and many cities in China, France, Spain, the United Kingdom, the United States, Japan and other countries have set new high temperature records. Frequent high temperature and heat wave events have sounded the alarm for climate warming.
Climate warming is one of the main features of global climate change. The Sixth Assessment Report of the United Nations Intergovernmental Panel on Climate Change (IPCC) pointed out that in the past 50 years, the rate of warming of the earth's surface has reached the highest value since 2000, and the intensity and frequency of high temperature and heat waves in most parts of the land have increased significantly. The frequency of occurrence has also almost doubled, and climate change will further intensify in the coming decades. The "China Climate Change Blue Book (2022)" pointed out that my country is a sensitive area of global climate change, and the rate of temperature increase is much higher than the global average level in the same period. In 2021, the daily maximum temperature of 62 monitoring stations in my country exceeded the historical extreme value, and this year broke the historical extreme value. The number of monitoring stations will far exceed that in 2021. Rapid climate change poses serious hazards to human health, especially exacerbating the spread, outbreak and prevalence of infectious diseases.
Infectious diseases are caused by pathogen infection and can be transmitted between humans, animals and animals, or between humans and animals, which can easily cause large-scale outbreaks and seriously endanger human health, economic development and social stability. At present, infectious diseases have shown new characteristics and new trends: First, the emergence of new infectious diseases is accelerating. The second is the accelerated expansion of the geographical scope of the epidemic of infectious diseases. Third, the epidemic season of infectious diseases has been prolonged and intensified. Fourth, outbreaks of infectious diseases are more frequent. Fifth, the epidemic scale of infectious diseases is larger. Sixth, the global pandemic of super-large-scale infectious diseases has occurred iteratively. The most representative one is the new crown pneumonia. One disease has six characteristics at the same time, which is the most in history. The overlapping occurrence of monkeypox and the new crown epidemic, and the "same frame" of two public health emergencies of global concern, not only set a new historical record, refreshed human cognition, but also fully demonstrated the necessity and urgency of building a human health community. There are many reasons for the new characteristics and trends of infectious diseases, including natural factors, social factors, human behavior factors and their interactions, but observations and in-depth research have confirmed that accelerated global climate change is an important driving factor for the new dynamics of infectious diseases.
Climate change can affect the growth, development, behavior, and interactions of pathogens, vectors, hosts, and susceptible populations, and change the pattern, frequency, and intensity of climate-sensitive infectious diseases. Taking the climate-sensitive disease vector biological infectious disease as an example, meteorological factors such as temperature, humidity, and rainfall can affect the development and reproduction speed of vector organisms and pathogens they carry, and regulate their population size, distribution, infectivity, and transmission ability, thereby changing the vector. Spatiotemporal dynamics, prevalence frequency and intensity of biological infectious diseases.
As far as temperature rise is concerned, on the one hand, a very small increase in temperature will cause great changes in the number and distribution of vector organisms; on the other hand, the reproduction and development of pathogens in vector organisms will also change. Take mosquito-borne diseases, for example. It usually takes 2 weeks for mosquitoes to grow from eggs to adults, but it only takes 1 week if the temperature is right. We assume that a mosquito lays 100 eggs at a time and can survive. This mosquito can produce a total of 5,000 mosquito offspring a month. When the temperature rises and the mosquito development period is shortened, a mosquito can produce 12,500,000 mosquitoes in a month. offspring!
It can be seen that an increase in temperature will lead to an exponential increase in the number of mosquito populations. At the same time, some areas that were originally unsuitable for mosquitoes due to the cold will become suitable due to rising temperatures. After the mosquitoes invade, they can "live and work in peace and contentment", endangering local residents. Mosquito-borne diseases that used to be found only in the tropics are now frequently found in subtropical regions and even in temperate regions. Statistics show that the incidence of dengue fever in the world has increased 30 times in the past 50 years, and the epidemic area has expanded to more than 100 countries. Driven by climate change, the frequency and intensity of dengue fever epidemics in my country have also increased significantly. The endemic areas have continued to expand northward and westward from tropical areas such as Guangdong, Hainan, and Yunnan, and have reached temperate areas on the south bank of the Yellow River.
Climate warming will also expand the distribution range of rats and ticks, and prolong their life history and harmful period. Warmer winter will expand the activity area of rats, reduce the death rate of ticks, put a large number of people in a potentially high-risk state, and increase the risk of rat-borne diseases and the spread of tick-borne diseases. Changes in population distribution, land use, and other ecological environments caused by climate change will inevitably affect the growth, development, and population vitality of rats, fleas, ticks, and other parasitic organisms. In addition, waterborne and foodborne infectious diseases are also affected by extreme weather events such as high temperatures, heavy rains, floods and droughts. If we do not curb carbon emissions and allow climate change to intensify, diarrheal deaths of children under 15 years of age will increase (especially in Africa and Southeast Asia), creating a large disease burden.
Overall, global climate change will increase and expand the frequency and intensity of infectious diseases, as well as the geographical and seasonal distribution of diseases, endanger public safety, and cause serious damage to society, families, and individuals. Therefore, we should fully understand the seriousness of the exacerbated epidemic of infectious diseases caused by climate change, formulate forward-looking, continuous and innovative precise control strategies and measures, strengthen the monitoring and early warning of climate change-sensitive infectious diseases, actively prevent and control the hazards of infectious diseases and carry out Risk Management. The medical and health system should strengthen infrastructure and capacity building, enhance the ability to resist extreme weather events and climate events, ensure that medical and public health institutions are maintained in good condition, prevent and control climate-sensitive infectious diseases, and protect the health and public health safety of vulnerable groups. In addition, we must actively promote low-carbon emission reduction actions, with everyone's participation, to reduce carbon emissions, slow down climate change, and curb the growth and increase of climate-sensitive infectious diseases.
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