Malaria
Long before the advent of Covid-19, malaria was claiming lives. Malaria is an infectious disease not caused by a virus or bacteria, but by a parasite called plasmodium. It is transferred by the saliva of female Anophele mosquitoes to human. There are over 200 million cases of malaria, with over 400 thousand people losing their lives every year due to this infection. Did you know that there is a congenital disease that can protect people from malaria? Sickle cell anemia is an inherited disorder of beta hemoglobin in red blood cells. Red blood cells in this disease can change into a sickle shape. Patients with sickle cell disease are more vulnerable to malaria but those with sickle cell trait (those who have only one sick gene) are resistant against malaria and if infected, their symptoms are less severe. The interesting point is that in Africa, which is endemic to malaria, there is a larger population of people with sickle cell trait, through natural selection.
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Columbian Exchange
Columbian exchange was not only the transfer of plants and animals between the old and new world, but also disease. Infectious diseases that had been endemic in the old world since the Neolithic era were unknown to the new world. Native people in the Americas had no natural immunity to diseases such as small pox, measles, yellow fever, influenza, and malaria. Many millions of these people in the new world died of these infections in a short period after Columbus's voyage. The only infection that possibly transferred from Americas to the old continent was Syphilis. Syphilis caused the death of millions of people in the beginning of 16th century in Europe and became an endemic disease there. The relative immunity of black people in Africa to the infections of the old world was one of the reasons that boosted exploiting black people as slaves in plantations in Americas, rather than native American.
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Leprosy
Legs of a Leper
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Leprosy is a chronic infection. It has affected humanity for thousands of years. Patients with leprosy may lose parts of their extremities and their faces may become disfigured. Leprosy has been associated with social stigma. In sacred scriptures such as Bible, leprosy has been referred to, as a punishment of wrongdoing. Lepers (people with Leprosy) were historically considered unclean and were separated from the rest of the society. One of these leper colonies was in Kalaupapa community in Molokai Island, Hawaii. The community had over a thousand patients until a cure was found. Today we know that Leprosy has a very low infectious rate and will be completely cured if diagnosed soon and treated properly.
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COVID-19
Infectious diseases are intertwined with history, geography, zoology, and even politics (and religion in the past). This is why studying infectious diseases is fascinating. The most recent example is Covid-19. It began in some unknown city on the banks of the Yangtze river. The city, Wuhan, soon became one of the most well-known cities in China, along with Beijing and Shanghai. The source of the infection was believed to be a market selling wild animals for meat, including bats, in the city. The infection soon spread to other cities and passed the borders into other far and near countries. Each country obtained a specific policy to confront the spread of the disease. Some did better some worse. Some countries were at one end of the spectrum blocking the entrance of the infection with strict laws, such as New Zealand and Australia; some other countries endured lots of infected cases and losses due to wrong policies and late decisions such as Brazil and Iran. Some countries let it go, for the people to reach herd immunity, like Sweden and Great Britain, some other countries imposed serious quarantine to isolate and eradicate infectious cases, like Italy and Spain. Each with gains and losses. Interesting!
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Sub-Saharan Diseases
While fertile crescent in the Middle East and North Africa was home to the earliest human civilizations during the Neolithic era, Sub-Saharan Africa was left relatively unknown and undiscovered for a long period. One of the hypothesis explaining this late discovery of the South was the endemic infectious diseases in these area, such as malaria, yellow fever, and sleeping sickness. Ones who dared to pass the Sahara into the unknown lands of South, got infected with these deadly infections and lost their livestock and horses. These infections were also a source of dread for Europeans venturing into Green Africa to find the source of Nile or cross the continent.
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Peptic Ulcer
My grandmother suffered from peptic ulcer. Her suffering was attributed to unhealthy food, the acidity of her stomach, and daily stresses. She had a bunch of pills to lower the acidity of her stomach and the level of her anxiety. It was not until some years ago that an Australian scientist discovered the cause of peptic ulcer (and gastritis): microbe, Helicobacter Pylori. He won the 2005 Nobel Prize in physiology or medicine for this great discovery. During his research he had ingested a culture of bacteria to investigate the results on his stomach which as he described, was more severe than he would have expected. Today, antibiotics, to fight Helicobacter pylori, is the main part of peptic ulcer treatment.
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Travelling to Foreign Countries?
When you have a plan to travel abroad, it is a good idea to consult with your doctor before departure. There are infections endemic to some countries and you may be at risk of getting those infections. Your doctor will check for you and inform you of the risks. There will be some health advices to avoid traveler's diarrhea. For traveling for some countries, you may need to get some vaccine shots. For example in some African countries yellow fever is endemic and you have to receive yellow fever vaccine some week before leaving for those countries. Some of those countries may require a document that proves you have received the vaccine. Also in countries where malaria is endemic, the doctor may prescribe you malaria tablet to defend you against this infection. Using mosquito repellent at all times and bed netting at night is very important in these areas. Scientist are working on an effective vaccine against malaria. Hope it will become available soon.
Spanish Flu
Before the advent of Covid-19 I didn't know much about the Spanish flu. The Covid-19 pandemic has led me, and possible others, to become more interested in similar events in contemporary history and the most important, the pandemic of recent history: the Spanish flu. A flu virus caused it. It happened after WWI. Now scientists believe that the origin was not actually Spain, but probably some other country in Europe. Spain was actually one of the few countries that remained neutral during the war and the news of the disease was not censored there as in other countries involved in the war. This is why for years many assumed Spain as the origin of the infection. There was no effective medicine or vaccine against Spanish flu by that time. It is said that over 500 million people became infected and around 30-50 million died during a period of two years.
The Path of Microbes
It is interesting to know that every microbe, bacteria, virus, or parasites have a port of entry in the body; they usually pass through the blood and settle preferably in some organ in the body. For example hepatitis A virus is ingested along with infected water or food and absorbed through the bowel wall. It then enters the blood stream and settles in the liver; while hepatitis B virus cannot infect the body through the mouth. It can be sexually transmitted or directly enters the blood stream by a contaminated syringe or needle. Some parasites have an amazing path inside the body. For example Schistosoma is a parasite flatworm. It enters the body through skin while someone is wading or swimming in a contaminated water. It migrates through the bloodstream to the lungs, heart, and then to the liver. These parasites go through different stages of maturation and proliferation on the way and finally end in the intestine or bladder and exit the body with defecation or urine. Isn't it amazing and terrifying at the same time!?
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Tuberculosis
The microbe responsible for Tuberculosis (TB) was first discovered by the German physician and microbiologist, Robert Koch. This is why this bacteria is also called Koch's Bacillus. But Tuberculosis has a long history. Traces of this infection, ruining the humans, has been detected in excavations since 7000 BC. Indications of spine infection has also been demonstrated in Egyptian mummies. King Tutankhamen of Egypt suffered from TB. Eleanor Roosevelt, George Orwell, and Nelson Mandela are among famous people who were infected with TB. Today, Tuberculosis is treatable with antibiotics; however this disease still claims more than a million lives every year around the world. Multi Drug Resistant TB is a new challenge in medicine; these cases do not respond to regular antibiotics and are a great challenge to treat. Patients with AIDS are specifically susceptible to TB with high mortality rate.
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