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Why is the epidemic so scary? Reveal the biological principles behind the epidemic!
When we face an epidemic, countless problems will arise. Why do certain diseases suddenly break out? What factors make the epidemic spread rapidly in a region? The answers to these questions are closely tied to fundamental principles of biology. In this article, we’ll take a closer look at the causes of epidemics, how they spread, and how to prepare for them.
Definition of epidemic
According to the U.S. Centers for Disease Control and Prevention (CDC), an epidemic is a sudden increase in the number of cases of a disease in a specific area that exceeds what is normally expected in that area
Epidemics are usually caused by changes in the ecological environment or changes in the pathogen itself.
Causes of epidemics
The occurrence of epidemics usually involves multiple factors, including antigenic changes of pathogens, drug resistance, changes in transmission routes, seasonal factors and human behavior. These factors sometimes interact to greatly increase the risk of epidemics.
Antigenic changes
Antigenic changes of pathogens are an important factor affecting epidemics. An antigen is a protein on the surface of a pathogen that the host's antibodies can recognize and attack. When a pathogen's antigenic profile changes, it may make it more likely to spread among previously immunized populations. There are two natural mechanisms for this change: antigenic drift and antigenic shift. The former occurs gradually due to genetic mutations over a period of time, while the latter is a process in which multiple different virus strains co-infect the same host and suddenly produce new subtypes.
The problem of drug resistance
Antibiotic resistance is another major challenge in epidemics.
Resistance is usually caused by bacteria acquiring it through genetic mutation or gene transfer. Continuous use of antibiotics promotes the selection of certain mutations, which render them ineffective against certain pathogens, especially in the increasing case of drug-resistant tuberculosis.
Changes in transmission routes
Pathogen transmission pathways also play a key role in the spread of epidemics. Transmission can occur through a variety of means, such as airborne transmission, food and water contamination, and contact infection. The characteristics of each transmission route influence how quickly and widely the disease spreads.
Seasonal factors
Some diseases can significantly affect their prevalence with seasonal changes. For example, influenza viruses are typically most prevalent in the winter, possibly due to changes in temperature and humidity.
Human Behavior
Changes in human behavior can significantly affect the frequency and severity of epidemics.
For example, during the 1854 London cholera epidemic, measures to remove contaminated water sources successfully reduced the spread of the epidemic. Urbanization and dense crowds often lead to outbreaks.
Types of epidemics
Epidemics can generally be divided into two categories: common source epidemics and transmissible epidemics. A common source epidemic occurs when all affected persons are exposed to a particle. A transmissible epidemic is the spread of pathogens from person to person, causing infection again and again.
How to respond to epidemics
Effectively responding to an epidemic requires multi-layered preparedness, including establishing disease surveillance systems, quickly dispatching emergency personnel, and ensuring the safety of medical workers. Early and aggressive mitigation measures, which often include social distancing, rigorous contact tracing, and appropriate personal protective equipment, are important.
Conclusion
Epidemics are complex phenomena, and the biological principles behind them involve multiple interactions among pathogens, hosts, and the environment. Facing the ever-changing global health challenges, are we fully prepared to deal with possible future epidemics?
