Bacteremia refers to the appearance of microorganisms in the blood. Most bacteria enter the blood from local lesions. Mainly occurs in the early stage of inflammation, macrophages in liver, spleen and bone marrow can form a line of defense to remove bacteria. It means that external bacteria enter the blood system through the entrance of the body surface or the entrance of infection, multiply in the human blood and spread throughout the body with the blood flow, with very serious consequences.

Horizontal transmission refers to virus transmission 1. Many viruses transmitted through mucosa are caused by mucosal infection; 2. Transdermal transmission Some viruses can invade the body and cause infection through insect bites or animal bites, injections or mechanical damage to the skin; 3. Iatrogenic transmission Some viruses can also be transmitted by injection, blood transfusion, tooth extraction, surgery and organ transplantation.

Virosome (English name) can be defined as core-shell structure, and its shape is spherical, filamentous, elastic, brick, tadpole and so on.