Coxsackie virus binds a large subgroup of enteroviruses. They cause a variety of diseases such as sterile meningitis, Helpangina, pleurisy, hand and leg mouth disease, muscle / pericarditis, cold, diabetes and so on. A and B, the pathogenicity of mice is different. Coxsackie B virus is the most commonly identified causative agent of viral heart disease in humans.
Characteristics of virus
General properties
Coxsackie virus is a typical enterovirus with a diameter of 28 nm.
Susceptibility of animals and growth of virus
Coxsackie virus is highly infectious for newborn mice. Certain strains (B1 to B6, A7, 9, 16) also proliferate in monkey kidney cell culture. In human amniotic membrane and human embryonic pulmonary fibroblasts, several group N strains proliferate. Chimpanzees and cynomolgus monkeys can be infected subclinically. Virus appears briefly in blood or throat and is excreted for 2 to 5 weeks. Type A 14 produces poliooid lesions in adult mice and monkeys, but this type results only in myelitis Type A7 strains cause paralysis and severe central nervous system lesions in monkeys.
Group A virus produces extensive myositis in skeletal muscle of newborn mice, resulting in flaccid paralysis without other observable lesions. Group B viruses can produce focal myositis, encephalitis, and most typically necrotizing atherosclerosis, mainly including fetal fat lobules. The inherited genetic makeup determines the susceptibility to Coxsackie B virus. Several B strains also produce pancreatitis, myocarditis, endocarditis and hepatitis in both mammals and adult mice. Corticosteroids can increase the susceptibility of aged mice to pancreatic infection. Normal adult mice tolerate infection by group B coxsackie virus. However, serious malnutrition or immunodeficient mice have greatly enhanced sensitivity.
Antigenicity
At least 32 different immunological types of coxsackie virus are not recognized. 26 is classified into group A and group B is classified into group 6.
resistance
Coxsackie and ECHO viruses have relatively high tolerance. They survive long-term in a frozen state of -70 degrees Celsius. In glycerin and horse serum at room temperature, they persist for 70 days. In the refrigerator, they have survived for more than a year. Coxsackie virus is similar to poliovirus in that it is resistant to various concentrations of hydrogen ions. They survive for 24 hours at pH 2.3 to 9.4 and 7 days at pH 4.0 to 8.0. It is resistant to antibiotics, 70 degrees ethyl alcohol, 5% Lysol solution, but very sensitive to hydrochloric acid and formaldehyde solution. Kill the virus in 30 minutes at a temperature of 50 to 55 degrees Celsius.
Etiology and pathology
The virus is recovered from the blood at the early stages of natural infection of humans and at the stage of experimental infection of chimpanzees. The virus is also found in the throat on the first few days of infection, and also by feces up to 5-6 weeks. The distribution of the virus is similar to that found in other enteroviruses. Group B Coxsackie virus may cause acute lethal encephalomyocarditis in infectious diseases. It seems to be a systemic systemic disease with viral replication and lesions in the central nervous system, myocardium and other organs.
