Rhinovirus and Coronavirus Almost everyone has experienced a cold, starting with a mild or severe discomfort in the throat, or a sneezing fit, soon followed by a cough and runny nose, sometimes with a fever, headache, and perhaps a feeling of weakness and muscle aches in severe cases. What is known as a cold or flu in everyday life is often referred to as a respiratory infection in medical terms. For adults, it is an upper respiratory infection, and for children, it is a lower respiratory infection. This is because children’s upper respiratory tract is so short that when an infection occurs, it can easily infect the lower respiratory tract as well. Because of this, children’s colds are more likely than adults to turn into more dangerous diseases such as pneumonia. The flu is a very common respiratory illness that occurs most often in early winter and fall, although it also occurs frequently in other seasons. It is caused by a variety of viruses, and although biologically these viruses may differ greatly from one another (for example, their genetic material is DNA in some viruses and RNA in others), they are grouped together in medical practice as respiratory viruses because they all usually cause respiratory symptoms when they infect the body, or are contracted solely through the respiratory tract. Common viruses that cause colds include rhinoviruses, adenoviruses, coronaviruses, respiratory syncytial viruses, and others. About half of all colds are caused by rhinovirus, an RNA virus, and fall and early winter are the favorite seasons for rhinovirus. The rhinovirus is particularly attracted to the environment of the nasal cavity of humans and our close relative, the chimpanzee, which is well ventilated and has a constant temperature of about 33 degrees Celsius, making it extremely suitable for survival and reproduction, which is why it is medically known as a rhinovirus. The incubation period of a cold caused by rhinovirus is usually very short, with cold symptoms appearing 2 to 4 days after infection, including a sore throat, nasal congestion, sneezing, mild headache, chills and general discomfort such as lethargy. At the same time, our nasal passages begin to show a large amount of watery discharge, which becomes mucus-like and purulent as the disease progresses to the later stages of the cold. In general, the presence of mucopurulent discharge does not indicate the presence of bacterial infection. Cough caused by rhinovirus is usually not severe but often lasts for 2 weeks, and almost no fever is the main characteristic of cold caused by rhinovirus infection. The combination of hundreds of different rhinoviruses and random changes in viral antigens, combined with the fact that the body’s immunity to rhinoviruses is not durable, leads to recurrent rhinovirus infections year after year. However, rhinovirus usually causes very little damage to the body and most of the time, colds caused by it can heal on their own without taking any medication, a characteristic that is called self-limiting. Since rhinovirus is responsible for so many colds, there is a lot of medical interest in how it spreads and whether there are easy ways to prevent it, and whether there are drugs that can shorten its course or at least reduce its infectiousness when we finally get infected. Studies have shown that rhinovirus is relatively viable compared to other viruses that cause colds, it is heat resistant and can survive on dry skin and surfaces of everyday household items as well as in the air. Usually rhinovirus can survive on hands for up to 70 hours and on surfaces for at least one hour. For this reason, rhinoviruses are highly infectious and on average, each family member infected with a rhinovirus cold will cause about 2/3 of the family members to become infected. Rhinovirus is mainly spread by direct contact but also by droplet transmission (aerosol transmission). When we blow our nose or rub our nose with our hands, rhinovirus gets on our hands and then the virus can be transmitted directly from hand to hand or through a route similar to hand-door handle-hand transmission. According to a study conducted by the Virginia Medical Center, there is a 40% chance of getting the virus on your hands when you blow your nose with ordinary toilet paper, and a 10% chance of spreading it to others through hand-to-hand transmission; if you blow your nose directly with your hands, the chance of getting the virus on your hands rises to 80%, and the chance of spreading it to others directly through hand-to-hand transmission also rises to 80%. As long as the person with a cold does not wash his hands thoroughly, then where the hands touch the virus will naturally stain, and once other people touch these items stained with the virus, and then through the way of rubbing the eyes and touching the nose, the virus can cause infection through the conjunctiva or directly into the nasal cavity. These studies suggest that the most direct and effective way to prevent colds is to wash your hands carefully. If you have a cold patient at home, you can also try to eliminate the cold virus in your room by heating vinegar to make it evaporate, because rhinovirus is more sensitive to acid, and disinfecting or strengthening the cleaning of tableware also has a hindering effect on the transmission of rhinovirus. Currently, some experimental drugs have shown some promise for the treatment of colds caused by rhinovirus. One drug, pleconaril, which was presented in SCIENCE NOW at the end of 2001, can shorten the course of a cold caused by rhinovirus by one day. This may seem insignificant, but we really shouldn’t expect too much from a disease that is supposed to be counted in days. In April 2002, Professor Hiroshi Ichimura of Kanazawa University in Japan discovered that a low-molecular substance called “MRL-2471” was able to inhibit the activity of rhinovirus, raising hopes for the development of a new cold medicine. However, all these experimental drugs are not yet available for sale in China, so we should continue to endure for about 7 days. So far there is no direct treatment drug for viruses caused by various types of viruses in the market, and the various cold medicines we generally take usually only relieve the symptoms caused by the cold, while the cold itself still has to go through its natural process before it really gets better. The high-dose vitamin C treatment that has been promoted by some people has been shown by many clinical trials to have no objective effect, but if you feel that eating it is effective, then you might as well try it, but be aware that overdosing on vitamin C can cause diarrhea and in rare cases, kidney disease due to stones. Coronavirus is famous due to the SARS epidemic some years ago. The coronavirus that caused SARS is a new virus and has only 50% homology with the traditional coronavirus. The traditional coronavirus is responsible for about 20% of common colds, and the symptoms of colds caused by this virus are similar to those of rhinovirus, and are also self-limiting, with a duration of about 7 days. Adenovirus and respiratory syncytial virus, on the other hand, often infect young children, and colds caused by them are usually more serious and require careful monitoring and prompt treatment. If you have ever been infected with respiratory syncytial virus, then when you are infected again, you will only have symptoms similar to those caused by rhinovirus. However, it is the main respiratory pathogen in young children and infants, with symptoms similar to a cold at first, but later causing severe pneumonia, bronchiolitis and tracheobronchitis. Infections caused by adenovirus, on the other hand, usually cause persistent high fever in young children. When it comes to colds, it is important to mention influenza. The Englishman john huzxam in 1743, based on the Italian phrase “un infuenza di freddo” – “the effect of cold” – used to describe the origin of a certain disease, coined influenza. ” – coined the word Influenza. Influenza occurs mainly from November to February, and millions of people are infected every year. Many times people confuse the flu with the cold, which is not true. The common cold rarely causes systemic toxicity and mostly manifests as respiratory symptoms, while the flu is distinguished from the common cold by severe and persistent symptoms such as high fever, generalized aches and pains, severe headache and persistent cough. Although the body’s reaction to influenza is more severe than that of the common cold, it can recover on its own after about half a month for healthy adults, and there are usually no after-effects. The influenza pandemic that swept through Asia, Africa and Latin America in 1918 was the darkest memory of mankind, and the disease has since become famous and intimidating. In the course of a year, it traveled around the world three times, taking the lives of 20 to 50 million people. The 1918 flu is often referred to as the Spanish Flu, because when it spread to Spain it somehow suddenly began to take on a grim face and 8 million Spaniards fell, and other countries fell one after another. For a century, scientists have wondered whether the Spanish flu was a variation of the human flu or a new human flu from the bird flu? And why did the flu have such a high incidence and death rate? And why did it mainly affect young adults in their 20s and 40s? We were puzzled by a series of questions. After persistent efforts and with the support of today’s molecular biology technology, scientists have finally deciphered the entire genome sequence of 1918 influenza in the laboratory. In the October 6 issue of Nature this year, the sequence of the last three genes of the Spanish influenza virus was deciphered, so that we get the complete genome of the virus. Almost simultaneously, in the 7th issue of the American journal Science, another group of scientists used this information to synthesize the virus artificially, an act that some call “summoning the devil”. Scientists tested the virulence of the synthetic Spanish virus and, not surprisingly, the current human flu virus was dwarfed by it. It replicated 39,000 times faster than the current human flu virus, causing weight loss in the mouse hosts and severe inflammation of the lungs, as described by the doctors of the day. And the mice inoculated with the virus all died within six days, while none of the mice that received the human flu virus died as a control. The new study also confirms that it is highly likely that the 1918 pandemic originated entirely from avian influenza, which may be the reason it was able to cause high morbidity and mortality because it was completely new to our immune system. But why do we have to summon this demon again, aren’t people afraid of what will happen if it escapes the laboratory? But after all, today is no longer 1918, we have much better medical conditions and more experience and measures to fight infectious diseases. And the people who survive today are the descendants of those who defeated the Spanish flu, so even if it escapes the laboratory, it is unlikely to cause the same catastrophe. In addition we already know quite a bit about it and are well positioned to be better targeted in terms of prevention and treatment. Today, when we are facing a huge threat of avian influenza, knowing the secrets of the Spanish flu is an important weapon in our fight against the next pandemic. From a statistical point of view the average normal adult gets the flu 2-4 times a year, while children can get it up to 10 times. The common cold is a minor illness, but the lack of proper understanding of it takes a toll on our society and individuals. If there is no secondary bacterial infection, taking antibiotics is useless for treating colds, and usually only young or weak patients need to prevent possible bacterial infections in advance. But in fact, a large number of antibiotics are misused in colds and flu, resulting in unnecessary expenses that are uncountable, and even more troublesome is that problems such as drug-resistant bacteria caused by misused antibiotics have become a huge threat to human health, and many previously controlled diseases such as tuberculosis are creeping back, causing increasingly serious medical problems. And in cases where cold symptoms have little impact on our lives, taking medications to control cold symptoms unnecessarily may also prolong the natural course of the cold, since most cold symptoms occur because the body is trying to fight the disease, and controlling them is likely to benefit the virus rather than ourselves.