This class has allowed me to explore some of the various diseases that have occurred throughout time. There have been some major diseases, some lasting centuries like smallpox or just a few years like Ebola or each strand of Influenza. I have enjoyed the getting to explore these diseases, as epidemiology has always been a field that interests me. In this reflection essay, I am going to talk about the vectors between diseases, and how they jump from either animal-human or from human-human.
Many of the diseases that cause catastrophic death tolls throughout the world were enzootic to begin with, or animal born viruses/bacteria. The most notable throughout history has been the Black Death, which still ravages the world today in Madagascar (Artifact 2). The Black Death completely devastated the world in the 14th century, wiping out a large majority of the European continent. With the germ theory, which wasn’t discovered until Dr. Robert Koch (Artifact 8), not being around, doctors had no idea what to do when it came to trying to prevent this disease. Many were struggling to believe that the disease came from God due to the nature of how deadly it truly was, and others believed it came from the way the planets were aligned in that year, giving the atmosphere a certain type of poisonous gas (Artifact 2). In reality, fleas were the vectors that originally got the Black Death started. Many of these small insects are devastating in the fact that they can wipe out entire countries from biting just one infected animal. The fleas bit some infected rodents and would then hitch on to humans, thereby transferring the disease across species. From that point, the Black Death became a human-human transmission, spread through the air and wiping out many civilizations. While it became an areal transmission, it would not have gotten its start without its vector, the flea, transmitting the bacteria into humans.
Another major vector in society has been the mosquito. Many people know that the mosquito is one of the deadliest creatures on the planet, solely due to the diseases that it carries from either human-human or animal-human. A disease that has been a problem throughout the world is malaria, which is carried by mosquitos. Malaria was originally a enzootic virus, but the mosquitos allowed it to transfer from animal to humans. There are many other diseases like this, with the one I researched being West Nile Virus (Research Paper). This virus is different in that it is solely avian in nature, so that when mosquitos contract the virus from the birds, it infects humans, but in the migratory patterns in birds. This allows for multiple types of mosquitos to infect the human race throughout the world.
While many of the main vectors are known to be insects, such as mosquitos and fleas, vectors are described as being anything that can transmit a disease. Typhoid is a different case, as it is an illness from ran or undercooked meat. Food is actually a common vector for typhoid, such as the case of the infamous Typhoid Mary (Artifact 3)(Contagion). In the movie contagion, it was shown that the virus had infected a pig, which while it was being prepared, had not yet been cooked. The chef, who would have had the virus/bacterium on his hands, did not wash his hands when he went to meet one of his customers. There, he transmitted the virus/bacterium to her and she began to spread it through aerial transmission. This allowed for the disease to continue the spread, but it showed how insects are not always the vectors for transmitting diseases. Typhoid Mary was another case, as she would serve food to the people that employed her, which were rich families, which in some cases was raw or undercooked. After they consumed the meal, they would for some reason come down with Typhoid (Artifact 3). This was strange at the time, because again people did not know about the germ theory and believed that Typhoid was a disease that spread about the common people. Typhoid was in fact another food born illness and was a good vector in transmitting the disease into humans.
There has been some talk about how to eradicate the vectors that transmit the worst diseases, specifically the mosquitos. There is potential for mosquitos to be eradicated from the world, but scientists don’t know what will happen if mosquitos do become eradicated. There might be a chance that something worse comes to take its place, which is not something the world needs. Or maybe it will just find another vector to transmit its disease, and this vector could be far worse in increasing the numbers of spreading the disease. There has also been talk of a gene drive-taking place to stop the spread of certain diseases that mosquitos can spread, while also keeping them alive. This is talking about how to alter the DNA of the mosquitos to where they can still contract the virus, but it does not allow them to transmit the disease after contracting it. Again, scientists just do not know the effects of what will happen, but the debate is alive now.
Vectors are terrible in the fact that they allow for diseases to be spread amongst the world, but knowing how to control them is effective in not allowing these diseases to spread amongst humans. Certain chemicals or insecticides like DDT have been effective in not allowing the mosquitos to get into the food supply or transmit the viruses into humans. Other practices like wearing sleeves has also proven effective in slowing the spread of the diseases. There are many ways to prevent the vectors from infecting humans, however, there is no way to completely eradicate all diseases and all vectors from getting to humans, and that is just something that human nature is going to have to live with.