In many different countries, mosquito infestations occur at various times of the year. The ones that occur throughout the summer originate from the ideal breeding conditions, which end with an explosion in the mosquito population. The itching and discomfort caused by mosquito bites are indisputable. When you scratch the bite, you irritate the surrounding tissue, which leads to the development of a red, raised lump on the skin. If you are bitten by a mosquito, does it mean that you are also at risk of contracting a disease?
The Rise in Animal Transmitted Diseases
The incidence of diseases transmitted by animals is growing at an alarming rate around the world, especially in the Far East. In the past, residents of Central Europe have been diagnosed with malaria despite having never left the area where they live. But veterinarians and other specialists believe that there is currently no cause for concern in this region for mosquito infection.
Researchers discovered a few cases of virus transmission in the previous year, despite the unusual nature of the transmission. The Sindbis virus is a mildly dangerous virus that can occasionally result in meningitis. It is carried by the common Culex pipiens mosquito.
However, the population of the Asian bush mosquito, also known as Aedes japonicus, is increasing at an alarming rate, especially across Central Europe. Throughout the past few years, areas that encompass a land area of approximately 2,000 square kilometers have been plagued by an extremely active vector of diseases such as the West Nile virus. It wasn’t until the year 2012 that researchers were able to prove that a breeding population of this particular species of mosquito had indeed been established in Europe.
The Asian tiger mosquito, scientifically known as Stegomyia albopicta, has already established a breeding population in the area. The bloodsucker known to carry exotic diseases has been linked to the transmission of viruses, including West Nile and tropical dengue fever. In recent years, the mosquitoes that are responsible for transmitting the dengue and chikungunya viruses to people have been discovered in southern Europe.
Dog Tapeworm Is Carried by Mosquitoes
The larvae of the canine tapeworm, Dirofilaria repens, were found for the first time in Europe. This part of the world did not have any previous encounters with the parasite until very recently. Although mosquitoes are the most likely vector for transmission of these parasitic worms to humans, dogs continue to be the most common hosts for them. As of yet, there have been no reports of human illnesses acquired in the area.
Researchers have detected larvae of the dog skin worm Dirofilaria repens in mosquitoes for the first time in Central Europe. The parasite was previously not native to the land. Parasitic worms are found in dogs, but in rare cases, mosquitoes also transmit the infection to humans. So far, however, no human infections acquired in the area.
So, people are still relatively safe for the time being. However, if global temperatures continue to rise this may change in the future.
Sources:
Johnson, N., de Marco, M. F., Giovannini, A., Ippoliti, C., Danzetta, M. L., Svartz, G., Erster, O., Groschup, M. H., Ziegler, U. (2018, December 7). Emerging Mosquito-Borne Threats and the Response from European and Eastern Mediterranean Countries. PubMed Central (PMC). https://doi.org/10.3390/ijerph15122775
William Harvey was a fascinating individual. It is striking to think that a single published work has changed the future of biomedical sciences and medicine more than any other publication in the past fifteen centuries. This work is Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus, published in 1628 by William Harvey. This thin book put an end to the physiology and medicine dogmas of Galenus of Bergama, which had been affecting the Western world since the beginning.
Who Was William Harvey?
William Harvey (1578-1657)
William Harvey was from a wealthy Folkestone family. He was the eldest of the seven brothers, of which five would later become traders in London. He got his bachelor’s degree from Cambridge University in 1597 and went on a long learning journey in France, Germany, and Italy. In 1602, he received a doctorate in medicine and philosophy from the University of Padova, where he attended the anatomy course of Fabricius ab Aquapendente (also known as Girolamo Fabrizio), who discovered the valves of the vessels. He returned to London immediately after graduation and was elected a member of the Royal College of Physicians in 1604.
Harvey had remarkable fame during his lifetime. He became the private physician of King James I and his son, Charles I. In addition to his intensive clinical practice, he became a physician at one of the oldest hospitals in London, St. Bartholomew’s. He was extremely patient, persistent, and careful as a scientist. It took 25 years for his studies to bear fruit. He once complained to a friend that his medical profession was damaged due to his publications on blood circulation and his colleagues’ being jealous of his reputation, which called him “crackbrained.”
He was aware that he was making a mark in the history of medicine and did his best to pursue his fame. He left part of his fortune to the Royal College of Physicians and gave Cambridge’s Caius College his birth house and the land around it.
William Harvey once said in On the Formation of Animals, 1651, that nature should be investigated; the paths it showed us should be boldly walked, because only by moving from lower to higher levels can we penetrate the very heart of the mystery of nature by consulting our appropriate senses.
Blood and heart
William Harvey performs an experiment to prove his hypothesis of blood circulation to King Charles I of England. (Rue Des Archives/album)
According to the teaching of Galen, blood was drawn from the liver and lung, flowing to the right side of the heart, and after passing through the ventricle, the tidal movement began between the left ventricle and the arteries. At the beginning of the 17th century, it was argued that the heart was the source of heat and that the lungs served to cool the blood. It was assumed that diastole (the rhythmic expansion of the heart) combines blood and air, and the warmed and revitalized blood enters the circulatory system. The blood being darker in the veins and lighter in the arteries was attributed to the different functions of the two vessels, such as the ability to feed tissues and maintain the vital spirit.
Harvey’s observations completely changed these ideas. He discovered that the left ventricle of the heart sends blood continuously and unidirectionally from the lungs to the main arteries and tissues, and that the blood from the right ventricle, through the last veins, is sent from here to the lungs. Harvey had come to the conclusion that the amount of blood coming out of the veins should enter the arteries for the systems to work properly. For this to happen, the outside blood had to move cyclically from the arteries to the veins. He thought that the same principle should apply to the circulation in the lungs; blood should flow from the right ventricle to the left ventricle through the lungs.
Ernest Board’s painting depicts William Harvey explaining his blood circulation theory to his tutelary Charles I.
The observation of the heartbeat being synchronized with the pulse resulted in the faulty idea that the heart and arteries may contract and relax simultaneously. It was believed that the heartbeat felt by the hand was the enlargement of the heart. Harvey was able to argue for this idea by directly observing the chest walls of the animals. The reason a heartbeat was felt by hand was due to the contraction of the heart when sending the blood out and the enlargement of the ribs when relaxing. So, the pulse in the arteries was not due to the diastole (enlargement), but to the systole (contraction).
William Harvey’s work, de Motu Cordis
A drawing from William Harvey’s de Motu Cordis, 1628, depicting forearm surgery.
To express his thesis about blood circulation in his work, de Motu Cordis, Harvey resorted to quantitative reasoning, which was a fairly new approach. He did not believe that the source of a large amount of blood, which was constantly entering the heart from veins, could only be the food consumed. He also noticed that the amount of blood flowing in the blood vessels was well above the amount needed to feed the various parts of the body. This simple reasoning resulted in the idea that a fixed amount of blood moves “cyclically” in the body. This contribution was truly revolutionary, and it would take many years for general acceptance.
But Harvey not only made discoveries but also created the experimental method that would be pursued in biology and medicine experiments hundreds of years later. The study always starts by asking questions (there were more than twenty such questions in the first part of de Motu Cordis), some of which are intended to politely demonstrate the absurdity of the current views, and the answers should be very clear.
These are followed by questions that form the basis of the experiment. At the heart of his method was vivisection—the practice of performing operations on live animals. This experimental technique opened all the doors for Harvey. The observation made at a certain point in time (i.e., the dissection of a dead animal) was not sufficient to answer some functional questions. Thus, continuous and sequential observations of live animals were necessary. The attachment, removal, and opening of the vessels of the body parts were the means of understanding and revealing normal physiology.
William Harvey’s curious mind
Exercitationes de Generatione Animalium (Exercises on the Generation of Animals) was published by Harvey in 1651.
From the first days of his professional career, Harvey realized that every new breed he worked with brought him new insight. The animal species he studied were diverse. In the later years of his life, when he switched to studying embryogenesis in animals, his highly curious mind was in the most open state possible. He had always had the maxim to be objective, but he could not help but admire the creation and the creator behind it. He was interested in embryology and its earliest stages of development. What happens first? What follows next? Such thoughts stand out in Harvey’s 1961 book, Exercitationes de Generatione Animalium.
In addition to his intense curiosity toward medicine, William Harvey was a revolutionary who pursued refined and disciplined thought processes while conducting biology experiments. The result was a fundamentally new understanding of how the human body works. He showed his students how to ask the right questions, deal with them, and answer them.
William Harvey quotes
“Very many maintain that all we know is still infinitely less than all that still remains unknown.”
“I profess to learn and to teach anatomy not from books but from dissections, not from the tenets of Philosophers but from the fabric of Nature.”
“The heart is the household divinity which, discharging its function, nourishes, cherishes, quickens the whole body, and is indeed the foundation of life, the source of all action.”
“Civilization is only a series of victories against nature.”
“Nature is a volume of which God is the author.”
“Moderate labor of the body conduces to the preservation of health, and cares many initial diseases.”
“I have often wondered and even laughed at those who fancied that everything had been so consummately and absolutely investigated by an Aristotle or a Galen or some other mighty name, that nothing could by any possibility be added to their knowledge.”
“Only by understanding the wisdom of natural foods and their effects on the body, shall we attain mastery of disease and pain, which shall enable us to relieve the burden of mankind.”
When William Harvey discovered the fact that the blood was circulating in the body in a closed system, it led to the idea of blood transfusion. A few moments after, Oxford physician Richard Lower started working on the dog-to-dog and animal-to-animal blood transfusions. In the 16th and 17th centuries, blood, milk, and saltwater transplants were carried out in various countries to meet the patient’s blood needs, but these often caused terrifying situations.
Discovery of Blood Transfusion
Karl Landsteiner.
By the 20th century, when microbiological research was prevailing on the scene, numerous scientific details were acquired about some infections, and more importantly, significant improvements were made to human cellular functions (white blood cells) and the responses of antibodies. The blood transfusion, and the revolutionary developments it brought with it, caused the 20th century to be called the “age of immunology.” The biggest development in this field happened in 1901.
Austrian physician Karl Landsteiner discovered this while working with unsuccessful blood transfusion samples. He mixed small amounts of blood samples with the blood samples of different patients, and the result was an agglutination (clustering) of red blood cells, but not always. However, the same agglutination sometimes resulted in deaths and illnesses. Because this was a result of the inappropriate blood transfusions. Based on this experience, Landsteiner discovered that this was due to the presence or absence of two antigens called A and B that adhere to the outer layer of the cell membrane in the red blood cells.
Later, he mixed the blood samples he took from his physician friends and separated them into either group A or group B as compatible or clustered. He found a type of blood type that did not lead to clustering when mixed with both A and B groups. Understanding that no antigens adhere to the outer layer of the cell membrane in the red blood cells, Landsteiner called this blood type the 0 (zero) group (which later turned into the letter “O”). After a series of shuffles and observations, he discovered a new group called AB, where the cells carry both antigens.
Unfortunately, the remaining details about blood transfusion could not be easily and quickly discovered. It would take another forty years to embrace the life-saving function of blood transfusion with the discovery of other antigens (Rh, M, N, andP), the emergence of anticoagulant drugs and blood storage products that prevent blood clotting, the establishment of blood banks, and the beginning of World War II. As a result of the widespread use of blood transfusions, diseases such as viral hepatitis and, later, AIDS, have emerged after blood transplantation. This has been eliminated by scanning the donors’ blood with the help of radioimmune analysis and other methods.
Blood Transfusion, and the Race Wars
The Nuremberg Law for the Protection of Blood and German Honor.
Today, we understand that the word “value” has deviated from its meaning and degenerated to be turned into a political tool, especially in the recent past. Mostly, when we look at the examples mentioned above, we realize this degeneration better. Before written history, even a single drop of blood was valued highly; it reflected our personalities, determined our race, and symbolized living species. In 1935, German doctor Hans Serelman had a patient in need of an emergency blood transfusion. This happened at a time when blood banks (except the first blood bank established in Leningrad in 1932) were not yet established and blood transfusions were made directly from the donor’s vein to the recipient’s vein. Serelman gave the patient his blood because there were no compatible donors. While he had to be praised for saving the patient’s life, he was sent to the concentration camp because he was a Jew, and the blood of the German race was contaminated.
In the years that followed, Germany began working on preventing eight thousand Jewish doctors from doing their job and reducing the Jewish “influence” in the field of medicine, among many other applications. German immunology studies focused on finding the differences between pure Aryan blood and Jewish blood, which had no contribution to science. The Nuremberg Law for the Protection of Blood and German Honor imposed significant limitations on the blood to be removed from the donor during the blood transfusion, “in the case of the donor carrying sufficient pure Aryan blood”, to create a pure Aryan breed.
American Racism
The US started accepting the blood of black people after the Pearl Harbor attack.
If we look at the United States, we see similar racial practices. The army was divided into two, and the Red Cross refused to collect blood from the blacks. After the Pearl Harbor attack, the need for blood was so high that the institution began to accept the blood of black people. He labeled and processed the blood taken from them differently. In the late 1950s, the state of Arkansas enacted a law requiring the separation of black and white people’s blood, while the state of Louisiana enacted a law that criminalized this for physicians who gave “blood of the black” to white people without permission.
Today, it is unknown how many deaths and suffering have resulted from widespread racial discrimination among black and white people. Some of the legislators that support these laws, policies, and practices are also the heads of the parties that govern us; It is they who decide who can get health care, the distribution of organs in transplants, who has the right to abortion, stem cell research, who can access secret medical documents, who will have the human genome, and the quality of the air we breathe and the water we drink.
