What does polio mean?

When a disease like polio occurs, we need to actively treat it. If it is not treated in time, it may have a great impact on the child's body. Many people do not understand what polio means? Tell everyone that after contracting polio, symptoms such as fever and muscle aches will occur. Let’s take a look together below!

Poliomyelitis, also known as "infantile paralysis", is an acute infectious disease caused by the polio virus. The clinical symptoms are fever, upper respiratory tract symptoms, limb pain, and in a few cases, flaccid limb paralysis.

There are records of similar diseases in my country during the Ming and Qing dynasties, which are called "infantile paralysis." With the widespread use of vaccination in recent years, the incidence rate has dropped significantly.

Polioviruses belong to the Picornaviridae family and the Enterovirus genus. The diameter is 20 to 30 nm, contains single-stranded RNA, and has no envelope. Under an electron microscope, it appears as round particles. It is present in large quantities in the patient's spinal cord and brain, and can also be found in the nasopharynx, intestinal mucosa and lymph nodes. According to its antigenicity, it can be divided into three serotypes: I, II and III, and there is occasionally cross-immunity between types. The virus can be cultured in human embryonic kidney, human embryonic tumor, monkey kidney and HeLa cells.

The polio virus is cold-resistant and can remain active for up to 8 years at low temperatures (-70°C). It can survive for several months in water, feces and milk, and can be stored for several weeks in a 4°C refrigerator. However, it is very sensitive to drying, so it is not suitable for preservation by freeze-drying. For heat resistance. It can be inactivated at 60℃ for 30 minutes, and can be quickly killed by boiling and ultraviolet radiation. It can withstand chemical disinfectants of normal concentrations, such as 70% alcohol and 5% tartaric acid soap solution. However, it is sensitive to potassium permanganate, hydrogen peroxide, bleaching powder, etc., which can be quickly inactivated.

[Epidemiology]

(I) Source of infection: Humans are the only source of infection for poliomyelitis. Patients can excrete toxins from nasopharyngeal secretions since the end of the incubation period. The fecal excretion period is from 10 days before onset to 4 weeks after onset, and in some cases up to 4 months. Since the number of asymptomatic infections can be 50 to 500 times that of symptomatic people, asymptomatic virus carriers are the most important source of infection.

(ii) The disease is mainly transmitted through the fecal-oral route, and daily contact is the main mode of transmission. Contaminated hands, food, supplies, clothing, and toys can all transmit the disease. In rare cases, it can be transmitted through airborne droplets.

(III) Infants under 4 months old rarely get sick, while children aged 1 to 5 years are most likely to get sick. In recent years, children have been widely vaccinated, so the age of onset has tended to increase. After the body is infected with polio virus, specific IgM first appears in the serum, followed by IgG and Iga two weeks later. Protective neutralizing antibodies can last a lifetime. After the illness, patients have long-lasting immunity to the same type of virus, and a secondary attack is rare.

4. Epidemic characteristics: The disease is widespread throughout the world, and is more common in temperate zones. The epidemic is sporadic, with the highest incidence in summer and autumn. There is no significant difference in incidence between tropical and subtropical regions among the seasons. In the past, type I virus was the most prevalent, with type III being the least prevalent. After large-scale vaccination, type I virus decreased and types II and III increased relatively. The original pattern of an epidemic every 3 to 5 years has also disappeared.

I would like to remind everyone that children need care. When children suffer from polio, they will experience symptoms such as muscle stiffness. These symptoms are relatively obvious, so we must detect and treat them in a timely manner and not delay. If we delay, it may lead to more serious consequences. I hope parents and friends can pay attention to this.