病毒 Anglais:

Under a microscope, some viruses appear quite beautiful.

Antibodies fight off infections and viruses.

Viruses will exist as long as man.

Throat and nose membranes hurt by dry air allow cold viruses to enter more easily. It is important to carry out sensible counter plans against the cold with heaters and against the dryness with humidifiers.

Infectious diseases are caused by prions, viruses, rickettsia, chlamydia, bacteria, pathogenic fungi and protozoa.