Virus infection, transmission and diseases


Viruses are the pathogens responsible for many infections. In contrast to bacteria , however, viruses are absolutely immune to antibiotics. Vaccinations against some viral infections exist, but not against all viruses.

What are viruses?

Viruses are genetic parasites. They attack both bacteria and higher cells and thus also organ animals including humans. They are biological packages that transport their genetic material (DNA) into the host cell. There the cell metabolism accomplishes what the viruses themselves cannot:

The host cell produces new viruses according to their DNA blueprint and dies. This releases thousands and thousands of these copied viruses. Since viruses do not have their own metabolism and cannot multiply themselves, they do not belong to the realm of living things.

Nevertheless, they must have evolved from living cells, as their biochemistry clearly indicates. The cells of all life forms can be attacked by certain viruses that are only “responsible” for them. This strict specialization is another characteristic of viruses.

Meaning & Function

Viruses cause cells to self-destruct. Their importance as pathogens in humans, animals and plants is therefore the focus of attention.Although bacteria and fungi also pose a significant risk of infection, some of these microorganisms are vital to humans. The skin flora, which protects us from many infections, should be pointed out here. The intestinal flora is better known, without which optimal digestion would be unthinkable.

On the other hand, among the naturally occurring viruses, there are no forms that are in any way useful to humans. As mere DNA transporters without an independent metabolism, viruses cannot be eradicated by antibiotics. Because antibiotics are deadly metabolic toxins only for bacteria. The medical treatment of viral infections therefore has narrow limits.

Antivirals are drugs that can inhibit the multiplication of viruses, but do not lead to their complete elimination. Despite all the risks that viruses pose as infectious pathogens, their modern importance for research and medicine must not be overlooked. Genetically modified viruses are already being used to treat bacterial infections. Viruses of this kind are used to fight bacteria that have become resistant to antibiotics.

However, there are also approaches to using specially modified viruses in cancer therapy . These “oncolytic viruses” attack and destroy only tumor cells and thus have a highly specific effect. The patient is spared the serious side effects of chemotherapy .

The efforts of somatic gene therapy are also promising : for example, hereditary diabetes should be curable in the future. In this approach, laboratory-modified viruses serve as vehicles (“vectors”) that inject healthy genetic material into organs with genetic defects.


However, viruses are primarily a constantly lurking danger. With each infection, their multiplication rate is in the millions, if not billions. Due to the occurrence of such large numbers in a very short time, a variety of mutations take place. New virus strains can germinate at any time and unforeseen.The annual outbreaks of influenza are therefore basically unpredictable. The global Spanish flu pandemic of 1918 and 1919 claimed at least 30 million lives. The situation of those infected with HIV is worrying today. Most of the approximately 50 million people affected live in the Third World. With a number of antivirals, doctors can inhibit virus growth and significantly prolong the lives of patients. But the severe side effects of drug therapy usually make HIV patients retire early.

For most patients in poor countries, AIDS is still a death sentence: they cannot afford the expensive drugs. The most effective way to get the human disease under control would be a vaccine. However, the development of such a serum has proven to be very difficult.

Many virus infections could be practically eradicated with vaccinations in the last century. Chickenpox , measles and polio play hardly any role, at least in western industrialized countries. Improved vaccination morale could also push other serious infections such as meningitis (tick-borne encephalitis or TBE) or hepatitis A and B into the background. No vaccine can be developed against the cause of the common cold because of its variability. However, the pathogens are not among the most dangerous of the viruses.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.