What are RNA viruses and what types are there?

In life, there are often various strange viruses that pose a greater threat to people. Among them, RNA virus is a relatively popular type of virus in recent years. This type of virus is relatively unfamiliar to most people, and little is known about its pathology and symptoms, but it does have a great impact on people's health. Let's take a look at what RNA virus is? What types are there?

RNA viruses are also called RNA-type viruses. Plant viruses, with a few exceptions (such as cauliflower mosaic virus), are almost all RNA viruses. The RNA virus coronavirus has a diameter of 80 to 160 nm and is an enveloped single-stranded RNA. During the replication of viral RNA, the activity of the enzymes in its error repair mechanism is very low, almost non-existent, so it mutates very quickly. Vaccines are developed and produced based on the fixed genes or proteins of the virus, so RNA virus vaccines are more difficult to develop. Reproduction: It is an obligate intracellular parasite. It cannot reproduce alone and must be inside living cells.

RNA viruses include: HIV, tobacco mosaic virus, SARS virus, MERS virus, Ebola virus (EBV), Spanish flu virus, influenza A (H1N1) virus, avian influenza virus, bacteriophages (some bacteriophages are DNA viruses), etc.

1. Hepatitis A virus (HAV): also known as type 72 virus, with a diameter of 27 nanometers and a molecular weight of RNA of 1.9×106. There is only 1 serotype. In addition to humans, chimpanzees, white-lipped monkeys and marmosets in South America are also susceptible. Chinese red-faced monkeys can also be infected. In recent years, it has been successfully cultured in monkey embryo kidney cells and human lung diploid cells. The incubation period of hepatitis A is 15 to 40 days. In the late incubation period and early stage of the disease, the virus is excreted through feces and is contagious. After contracting the disease, you will gain lifelong immunity. The disease heals well and rarely becomes chronic.

2. Swine vesicular exanthematous virus (SVDV): There is only one serotype. It shares common antigens with human Kouksaki virus type B5, and immune serum can cross-neutralize it. Pigs are the only natural host and infection is mainly through wounds. Blisters occur on the oral mucosa, nose, udder, and hooves, and the appearance is difficult to distinguish from foot-and-mouth disease. The virus mainly exists in the blister skin and blister fluid, and the internal organs and muscles contain very small amounts of virus. The viruses in the blister skin are resistant to strong acids and alkalis. The virus can be cultured using primary porcine kidney cells or passaged cells and produce lesions. Vaccination with suckling mouse attenuated vaccine, tissue culture attenuated vaccine, blister skin and blister fluid inactivated vaccine can control the spread of this disease.