Measles is an acute viral infection because the causative organism is called the measles virus. Before vaccination, almost every child gets measles. The measles virus is found in the eyes, nasal secretions, blood, and stool of affected children and enters the respiratory tract of other children, mainly through respiratory droplets, so it is a respiratory infection. Most children get the disease from direct contact with a child with measles, or from close proximity. Because measles virus does not survive long in the air after it leaves the body, it is less likely that a non-close contact will get the disease. When the measles virus enters the body, it first invades the upper respiratory tract, throat, and then invades the bloodstream causing viremia. The incubation period from the time the measles virus enters the body to the appearance of symptoms is called the incubation period, mostly 10 to 11 days, as short as 6 days or up to 21 days. If blood transfusions or placental globulin injections have been given in the recent past, the incubation period can be extended to 28 days. Clinical manifestations include lacrimation, runny nose, cough, hoarseness and other symptoms of pharyngitis, which are similar to general upper respiratory tract infections and are sometimes mistaken for colds. Some infants may present with gastrointestinal symptoms such as vomiting and diarrhea. The rash is usually seen on the third or fourth day of fever, starting from behind the ears and neck and quickly spreading from top to bottom to the whole body and finally to the extremities. It is a red papular rash of varying sizes, scattered or densely fused. This is the extreme stage of the disease, and all symptoms are aggravated. In severe cases, the rash is sometimes hemorrhagic, or the rash is sparse or pale, and the rash usually subsides within a week. Rubella is an acute infectious disease caused by the rubella virus. Rubella is mainly seen in children, mostly within 3 years of age, and has a high incidence in winter and spring. The virus can be discharged from children with rubella from six days before the rash to two days after the rash, and can be transmitted directly to other children through secretions from the mouth, nose and eyes, or via respiratory droplets. The first time you get rubella, you get lifelong immunity and rarely get it a second time, so those who develop it after contact are mostly susceptible children without antibodies in their bodies. The virus is present in the herpes fluid and also in the pharynx, and can be transmitted by droplets, as well as indirectly through a third party and toys, books, and utensils. Both chickenpox and herpes zoster are caused by herpes zoster virus, the former is mainly seen in children, the latter is mostly seen in adults, children can cause chickenpox after contact with adults suffering from herpes zoster. The disease is most common in winter and spring, and can affect children of all ages, but is more common in infants and preschoolers. There are very few people who get chickenpox for the second time in their lives. The incubation period of the disease is generally 16 to 17 days, but also seen as little as 1 week, up to 4 weeks. The onset of the disease is feverish, most do not exceed 39 ℃, occasionally more than 40 ℃. The fever lasts 1 to 5 days and then decreases to normal. A rash can be seen on the body at the same time as the fever, or one day after the fever. The rash is more on the head and trunk and less on the extremities, but occasionally on the palms of the hands and soles of the feet. The rash is initially a small red macule or papule, which changes to an oval-shaped herpetic rash of varying size with a red halo around it after about a few hours to a day, followed by a flattening of the herpetic rash with a central depression and a crusty cover. Since the rash appears in batches, the various forms of the rash described above can be seen at the same time and are characteristic of the disease rash. Herpes can also be seen on the oral mucosa, eventually forming ulcers. In severe cases, a hemorrhagic rash can be seen. Pediatric “influenza” Influenza is short for influenza, a respiratory tract infection caused by a virus. The virus is contained in the respiratory secretions of the patient, and can be transmitted directly to others by droplets, or indirectly by spittle staining utensils, books, clothes, and hands. Since the virus can only survive in the air for about 30 minutes, direct transmission is the main reason. Influenza viruses are most contagious within the first 3 days of illness. There is no cross-immunity between the types, and the body may produce antibodies after infection with a certain type or subtype, which can only prevent the second disease for that type or subtype, but not for other types, so when infected with other types of viruses, the disease can still occur again, so “influenza” occurs many times. Enterovirus infections are more common in summer and fall and less common in winter, and can be seen in children of all ages, including newborns. The virus can be found in the nasopharynx, feces, blood, urine, pleural fluid, bone marrow, heart, brain, liver and other internal organs of the child, indicating that it causes a wider range of lesions than polio, which is different from polio and can be transmitted via the placenta. Encephalitis B Transmission Epidemic encephalitis B, also known as encephalitis, Japanese encephalitis, and epidemic encephalitis, is an acute central nervous system infection caused by the encephalitis B virus. This virus can not only make people sick, there are a variety of animals (pigs, cattle, sheep, donkeys, mules, dogs, cats, chickens, ducks, geese, etc.) can also get sick, with pigs having the most morbidity. Pigs are the main source of “BSE” infection. About 1 month before the occurrence of B encephalitis in the population, B encephalitis occurs first in the pig herd. B encephalitis virus can not be transmitted directly to people, but to mosquitoes as a vector. Therefore, the virus is also known as an insect-borne virus, and B encephalitis is also known as an insect-borne virus infection. The mosquito bites the sick pig with B encephalitis virus, the virus can be sucked into the body. The virus multiplies in the mosquito body, can exist for a long time, but also the virus can be transmitted to the next generation. When the mosquito bites a person, the virus will be injected into the human body through the skin. If the person does not have immunity against B encephalitis virus, it can occur epidemic B encephalitis.