How are viruses infect humans and how vaccines are manufactured?

In this article we are going to discuss how are viruses infect humans and how vaccines are manufactured? Let's get started. Firstly we will know all about viruses. 

About virus:

The first human virus was proposed by Walter Reed in 1901. 

Viruses are everywhere from our surroundings to the very food we eat, we ingest, inhale and, take in millions of viruses every second. Pretty much all life on Earth has some kind of virus designed specifically to infect it including bacteria and even other viruses. Viruses are tiny very tiny you cannot visibly see them they are so small that if bacteria had eyes even they wouldn't be able to see all of them. Most scientists accept that viruses are not living but a complex collection of organic matter that can self-replicate. They mostly consist of a shell made of protein which inside contains either DNA or RNA with enzymes for replication and manipulation of their genetic materials.

How are viruses infect humans?

Let's look more closely- a virus is just a piece or strand of genetic information usually DNA or RNA which can be single or double-stranded this is the viruses genome it uses this with the help of various molecular machines to replicate itself. However it cannot do this alone it must inject some kind of cell. Cells are the smallest unit of life, they manufacture proteins, replicate DNA, and store resources. This makes them perfect hosts for viruses armed with its genetic material. Viruses can infect healthy cells and convert them into mindless virus-producing robots. The virus uses this outer protein coat covered in small molecular receptors to bind and join to the membrane of a cell. 

This is essential as it is what determines which cells a virus can infect. Once joined the virus uses several complicated biological pathways to force the cell to either accept its genetic material or take in the entire virus itself once in the cell. The virus will then begin to use its molecular Arsenal to hijack the cell's protein manufacturing systems and DNA replication mechanism. After the virus has integrated itself into the cell's DNA the cell will then replicate its DNA and use it to manufacture proteins without the cell even knowing. It creates viral protein shells filling them with virus DNA completely making copies of the virus and collecting them. The virus producing machine starts to take over more and more of the cells. Protein manufacturing ribosomes churning out thousands of new viruses that quickly fill the cell. These viruses then cause tension within the cell and by several different means, bursts from the cell to infect new hosts for the same purpose seem like relentless biological vandalism to me.

Viruses are not all bad though some are being used to help strengthen disease resistance in crops whilst others such as HIV are being used in curing certain types of cancers. But what is the most remarkable of all is that many scientists believe some viruses that infected bacteria billions of years ago helped form the first cell nucleus. If this is true then all complex cellular life on Earth descended from a single virus and his rubbish attempt at trying to infect a bacterium. Now that is remarkable you. 

About vaccines and how vaccines are manufactured?

Historians have found that the origin of vaccines goes back to ancient Asia and Africa. Early versions of what is now called vaccines are believed to have been discovered in response to a deadly disease known as smallpox which was widespread across many cultures and countries and affected rich and poor people equally. Fortunately vaccine light treatments were developed to protect people against the sickness in Asia. A technique known as variolation was used involving a person being purposefully infected with smallpox by placing pus from a smallpox or under their skin. This caused a milder disease than a full smallpox infection and resulted in the person gaining lifelong immunity. While widely practiced in Asia and Africa this was viewed with skepticism by European physicians and smallpox killed approximately 400,000 Europeans a year in the 18th century. 

In 1796 Edward Jenner an English doctor demonstrated that cowpox virus treatment could also prevent smallpox disease. This works because the two viruses look very similar to the human immune system though. Jenner did not know that at the time. Jenner injected an eight-year-old boy with pus Kia taken from a cowpox or on the hand of a milkmaid. The little boy had a mild illness, not at all dangerous like smallpox and he recovered quickly. When Jenner later deliberately exposed the board to smallpox he didn't get sick his immune system was trained to fight off smallpox infection because of his prior exposure to cowpox. A fun fact, Jenner created the word vaccine from the Latin word Ibaka which means cow and vaccinia which is Latin for cowpox. Although injecting someone with pus caused by cowpox might sound gross Jenner's discovery. Ultimately led to the development of modern smallpox vaccines and wiped out smallpox, an amazing public health achievement. It was also the beginning of more vaccination discoveries and development. 

Vaccine research continued to boom throughout the mid 20th century. Scientists began growing viruses in laboratories leading to discoveries. 

One huge triumph of the time was the creation of the polio vaccine. Polio is a deadly virus that infects the central nervous system and can cause paralysis. It went from being a very common dangerous disease to one that is very rare. Because of the polio vaccine the development of vaccinations has allowed researchers to compact other common and sometimes deadly childhood diseases such as measles mumps and rubella. Very few people in our day and age have heard of some of these diseases. Since vaccines have dramatically reduced the number of cases of these and many other childhood diseases so at the end of the day we owe a big thank you to the individuals who were injected with pus by doctors in Asia.

Dr. Jenner helped to solidify the idea of training the immune system for future protection and for that we thanked the development of vaccine diseases such as polio measles and chickenpox are now preventable and parents no longer have to watch their children suffer from these once-common illnesses. 

So this is all about how are viruses infect humans and how vaccines are manufactured? I hope you liked this article. Also, I request you to share the article with family and friends.

(All content and images are for educational purpose).

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