Positive Effects Of Microorganisms And Vaccination On Us Public Health

Over previous centuries, how epidemic diseases and infectious diseases came to be were previously formulated based on mere observations, until several achievements resulted in widespread knowledge on how to effectively control infectious diseases.

Before the existence of microorganisms, there was no way to classify the different microbes. They were differentiated by grouping them into the plant kingdom or animal kingdom.

Until the late seventeenth century, Carl Woese came about a way to classify microorganisms based on their cellular organization. He grouped microbes into Bacteria, Archaea, and Eukarya. How each domain differ and relate are now the subject of research for biologists (Tortora et. al, 2019). After the discovery that all living things were composed of cells, the process of spontaneous generation came about. It was believed by scientists that lifeforms could exist spontaneously from nonliving matter, with several experiments trying to strengthen the hypothesis as well.

It was not until 1861, Louis Pasteur disproved the theory. Pasteur was able to support the theory of biogenesis, which states that living cells arise from preexisting living cells. He showed that microbes already in the air, were responsible for any life present in any nonliving matter. It is now believed that when life first began, spontaneous generation might have occurred but not under the conditions we live in today (Tortora et. al, 2019).

“Early explanations for the occurrence of disease focused on superstition, myths, and religion. Primitive peoples believed in natural spirits that were sometimes mischievous or vengeful. The Greeks believed that the god Jupiter was angry about man accepting the gift of fire” (BUSPH, 2015). Before the time of Pasteur, individuals also believed diseases were a punishment for the crimes they committed.

Overall, the causes of disease were unknown and treatments were based on trial and error. This was the case until Pasteur discovered the germ theory of disease, which means that microorganisms might be the cause of diseases. “The first proof that bacteria actually cause disease came from Robert Koch in 1876” (Tortora et. al, 2019). Furthermore, a key event that changed the understanding of infectious diseases was the cholera outbreak in London which happened in 1854. Before that time, people thought that cholera was spread because of bad air. This was the theory until John Snow was able to postulate that the disease was caused by an infecting organism. He further discovered that cholera did not enter the body through bad air, but rather through the mouth (WHO, 2007).

Before Pasteur discovered how vaccines work, “in the 1500s, physicians in China had immunized patients from smallpox by removing scales from drying pustules of a person suffering from a mild case of smallpox, grinding the scales to a fine powder, and inserting the powder into the nose of the person to be protected” (Tortora et. al, 2019). “In 1886, Pasteur successfully immunized a boy who had been bitten by a rabid dog with spinal cord suspensions of inactivated rabies virus. Before this, rabies-prone wounds were treated by cauterization or by inserting long, heated needles deep into the wound or sprinkling gunpowder on the wound and lighting it” (Smith et. al, 2012).

Now we can be immune to diseases such as smallpox provided by vaccination. In addition, human hookworm disease was first encountered in 1843, but at that time it was believed to spread through fecal-oral route (by ingestion). This was until Arthur Looss discovered that the hookworm parasites entered humans by penetrating the skin. He did this through self-experimentation, by first ingesting hookworm larvae and then exposing his skin to hookworm inoculum (Nelson et. al, 2014).

Before antibiotics were developed in the early twentieth century, bloodletting was used as a cure for infections. “Infections were thought to be caused by an excess of blood, so blood was removed from the afflicted patient. One method was to make an incision in a vein or artery, but it was not the only one. Cupping was another common method, in which heated glass cups were placed on the skin, creating a vacuum, breaking small blood vessels and resulting in large areas of bleeding under the skin. Most infamously, leeches were also used as a variant of bloodletting” (ACSH, 2016).

The first antibiotic was discovered by accident from a fungus. Penicillin became very common, and its discovery has since led to the discovery of other types of antibiotics.

Overall, all these achievements and discoveries have led to a decrease in infectious disease deaths in the United States. Also, identifying microorganisms that cause infectious diseases has led to a better understanding of prevention, treatment and disease management.