Since ancient times, the battle between humans and the virus has never stopped. Humanity has won, allowing our lives and inheritance to continue. In ancient times, medical technology was very underdeveloped, and the arrival of a serious illness often took away tens of thousands of lives. On several occasions, a country or a nation has been wiped out with casualties, which is more terrible than the casualties caused by war.
Smallpox, one of the ancient viruses with the highest mortality rate. The raging smallpox was called "the largest genocide in human history" by historians. It is said that at that time, the European colonists gave the blankets used by smallpox patients to the Indians. Then the plague raged, reducing the original population of 20-30 million indigenous people in the Americas to less than 1 million within a hundred years. However, what makes people feel a little more relaxed is that after being vaccinated against smallpox, they will have lifelong immunity, and the smallpox virus is almost extinct and is harmless to modern people.
Yellow fever is an acute infectious disease caused by yellow fever virus and mainly transmitted through the bites of Aedes mosquitoes. Yellow fever has a high mortality rate and is highly contagious. It was a fatal infectious disease in an era of underdeveloped medical care. In 1648, yellow fever first attacked the Caribbean islands of St. Kitts, Barbados, and Martinique in the Americas, and extended to as far away as Cuba and Yucatan, passing through unsuspecting people and razing many villages and towns to the ground. Yellow fever caused an even greater disaster in the Mississippi Valley in 1878, with more than 120,000 people infected and at least 20,000 dead. Finally, people developed a vaccine and was effectively controlled.
I personally experienced SARS in 2004. SARS is also known as SARS. It is an acute respiratory infectious disease caused by SARS coronavirus infection. It is a special type of pneumonia that can affect multiple organ systems. The pathogenesis of
is believed to be mainly related to the immune damage induced by coronavirus . After the virus invades the human body, viremia may occur in the early stage, causing damage to the body's cellular immunity, abnormal immune responses, and lung damage. It usually occurs in winter and spring, and can occur in all age groups, but it mainly affects young adults. Typical symptoms include high fever, chills, chills, muscle aches, dry cough, headache, dizziness, etc. It is highly contagious and is mainly spread through droplets and contact. But in the end we overcame it.
