Lately, we've become familiar with news about the coronavirus (COVID-19). We hear about possible infection routes, preventive measures, and potential symptoms. However, many of us still don't fully grasp what a virus is and its characteristics.

A virus is the smallest infectious agent, with a diameter ranging from about 20 to 300 nanometers. Unlike bacteria, which have two types of nucleic acid, viruses have either RNA or DNA as their genetic material. Viruses can only replicate within living cells, so viruses present in the air, water, and our environment cannot replicate (increase in number) until they find a living host cell with the appropriate receptor for that virus.

The genetic material of a virus is wrapped in a protein coat surrounded by a lipid membrane. This makes viruses vulnerable to substances that can dissolve lipids, such as alcohol or detergents. Regarding the coronavirus, virologist Dr. Andrew William Tulle M.Sc. from Brawijaya University (UB) in Malang explains that the coronavirus has an outer envelope, and if this envelope is damaged, the virus becomes inactive. However, compared to other viruses with envelopes, the envelope of the coronavirus has better survival capabilities in the environment. The factors that make the coronavirus more stable are not yet clear. A complete virus particle, including its envelope, is known as a virion. The virion's role is to transfer the virus's genetic material from one host cell to another.
The structure of viruses is significantly different from bacteria, making viruses more resistant to antibiotics. However, viral infections can be defeated by our immune cells or the host's immune response. Individuals or animals who recover from a viral infection develop immunity, enabling them to resist future attacks.

There are various environmental factors that can damage viruses, including temperature, humidity, pH, radiation, detergents, and certain chemicals. Generally, viral infectivity can be compromised by heating to temperatures of 50-60 degrees Celsius for 30 minutes (though some viruses are heat-resistant). In terms of pH, most viruses are damaged under basic conditions. Recent research from the National Institute of Health (NIH) in the United States suggests that the coronavirus can survive on surfaces for up to eight hours. Additionally, viruses can persist on inanimate surfaces for a significant time, even up to 72 hours on iron and plastic. However, the viral load decreases by around a third, and it's still unclear whether the virus remains infectious.

Source:
Veterinary Microbiology, 1999.
Jawa Pos, Radar Malang, March 31, 2020