Confusion between virus and bacteria is frequent. These two types of microorganisms are however very different, in their form, their mode of action but also in the tools we have to fight them.
The bacteria, a living and autonomous microorganism
The bacterium is an autonomous biological entity measuring from 1 to 10 microns. Unicellular organism without a nucleus, the bacterium is provided with a nuclear apparatus made up of DNA, a flagellum which allows it to move and a protective capsule. It can be aerobic, which means it needs oxygen to thrive, or anaerobic. It can reproduce by dividing and proliferate in different environments that are favorable to them. They are found in the human body but also in water, earth or in suspension in the air.
Bacteria are not necessarily pathogenic, quite the contrary. Present in large numbers in the digestive system, the famous microbiota, they are essential for its proper functioning. The presence of many bacteria in the skin also helps to form a barrier to infections. They are also bacteria which are at work in certain natural phenomena such as fermentation.
What diseases are caused by bacteria?
While not all bacteria are bad, others can cause potentially serious illness when they invade the body or release toxins. Among the diseases that can be caused by bacteria are urinary tract infections, angina, ear infections, bronchitis, tuberculosis, cholera, leprosy, gastroenteritis, genital infections, whooping cough, disease of Lyme, meningitis. Bacteria can also be responsible for serious food poisoning such as listeriosis, salmonellosis and botulism.
Bacteria have different modes of transmission: through the air when a person coughs or sneezes for example, by ingestion of water or food contaminated with a pathogen, parenterally, for example with a syringe, or by direct contact with contaminated skin or surface.
What are the different types of viruses?
Unlike the bacteria which is a cell, the virus has a very simple structure. Smaller than the bacteria, the virus measures 20 to 500 nanometers. It is made up of DNA or RNA (ribonucleic acid) surrounded by a protein structure called a capsid and sometimes, but not always, an envelope. We will therefore establish the classification of viruses according to the nature of the nucleic acid of the genome (RNA or DNA), the shape of the capsid and the presence or not of an envelope which is also called peplos.
- DNA viruses: Varicella Zoster Virus, Hepatitis B, Cytomegalovirus, Eptein-Barr, Polyomavirus, Herpes etc.
- ARN virus: Coronavirus, Rabies, HIV, Flu, Mumps, Measles, Hepatitis C, Ebola, Choriomeningitis, Rotavirus, Yellow Fever, Rhinovirus, Poliovirus etc. Viruses, whether DNA or RNA, are transmitted through air, water or blood, through direct contact or through sexual intercourse.
Where the bacteria can proliferate on their own, the virus needs another organism to reproduce. It is therefore totally dependent on the cell it parasitizes. One question agitates the scientific community, however: is the virus alive? This question is widely debated and two opposing views. For some scientists the fact that the genome of the virus does not allow it to multiply on its own and that the virus needs a host cell. Conversely, other researchers note that if the virus is indeed not living permanently like a bacterium, it is when it invests the cell and proliferates.
Why are antibiotics ineffective against viruses?
If the campaigns of the Ministry of Health have borne fruit, many patients are still surprised when they leave their doctor without a prescription for antibiotics. There is, however, an excellent reason for this. Antibiotics are active substances which will act on bacteria by blocking their development and proliferation. They are ineffective on most viruses.
Be careful, however, many infections combine bacteria and viruses, including certain respiratory viral infections. It is therefore common that an antibiotic is prescribed, even in the case of influenza for example, to avoid a bacterial superinfection if the risk of complications exists.
Read also :
⋙ Semmelweis, the misunderstood “genius” who preceded Pasteur
⋙ The first insect vaccine could help save bees
⋙ Bacteria to strengthen the dams
–
