The organs they infect may not be capped, leading to various strange symptoms and complications; as mentioned above, there are many zoonotic infectious diseases that can be transmitted across species , Bats are the common natural host of many human viral infectious diseases, but there are also viruses that are very special to humans, such as the polio virus commonly known as polio virus, which only exists in humans. I myself have been ravaged by viruses like flu, noro and dengue, and of course I hate them to the core, but they don't have feelings for us.
They make people sick or die, and they are simply old picture restoration subject to selfish genes - just copying themselves like crazy. Those symptoms of sneezing, coughing, vomiting and diarrhea, bedridden, etc., are just good for their transmission. If they kill the host too quickly, they will also die together, so infectious diseases with too high mortality rarely lead to large-scale outbreaks. Of course, we have to sit still, and if we survive, our immune system will hold a grudge.
Smart people have used this to develop various vaccines. Some infectious diseases, such as smallpox, that have plagued mankind for centuries, can be said to be completely extinct under the condition of widespread vaccination of mankind. Polio, which was common in the past, has also become a rare infectious disease. 1 2 » Read the full text Don't want to paginate? Try our new service you may also like Physicians answer from