Diseases have had an important role throughout history. Life would have been completely different without the role of diseases in society. It was interesting to learn about the evolution and discovery of different diseases. From what I have learned a large amount of the diseases we have today are due to anthropogenic causes. Humans have lived alongside diseases since the beginning of humanity and will probably be there till we go extinct. I think it is amazing how diseases effect people not just physically but mentally and culturally as well.

Before the population got so big during the hunter gatherer times, the people were not as exposed to the rotting meat and night soil because they were constantly moving. The tribes were also small and spread out so that did not have the opportunity to pass it around to other people through contact. The main thing they were infected with were the worms, lice, and fleas but they occasionally ran into some bad microbes when they were able to catch live meat. Then the population started expanding and they required more food in order to support the growing population. The increase of agriculture created more population density which in turn allowed for more reproduction which needs more food. This cycle cause the population of humans to grow tremendously and people started getting more densely packed. The new sedentary lifestyle they adopted kept them in close contact with animals and the major diseases came from evolving animal diseases. As the population kept growing they need more land and wood which lead to them clearing out forests which killed animals and allowed the spread of insects and rodents. The most common diseases today are all relatively recent due to the clearing out of forest. The consumption of bush meat is also a problem in poorer countries where they can’t find any other food sources. It is thought that bush meat has been the cause of Ebola and AIDS. Now in the modern era we can fly across the ocean with little effort allowing for easy transmission of a disease from one country to the other. As the population has been increasing our climate change potential has also been increasing due to the use of greenhouse gas emissions, cars and factories. The primary risk due to climate change is the heat waves, extreme weather, events, and temperature. The secondary risks affect the amount of food, water flow, infectious disease vectors, and immediate host ecology for zoonotic disease. The tertiary risks are the consequences after the resources are depleted.

The Black Plague was one of the diseases that decimated the human population. The Black Plague happened three times throughout history. The first one was known has the Justinian Plague that occurred in 542 AD, the second is the popular Black Death in Europe, and the third is the modern plague. The bacteria that cuases the black plague is Yersinia pestis which is found inside of the fleas on rats. The origins of the disease can be traced back to somewhere between India and China. The Black Plague spread two ways, through the blood or it can reach the lungs which makes the disease airborne. The Mongols are the ones who spread it around to different countries through their conquest. There was also a lot of trade that was going on during this time which allowed for the transmission of the disease from one city to another. Because the cities were so population dense it only took one infected person to spread it throughout the city and cause an endemic. People were dying in large numbers and people had no idea what the cause of the disease. This caused a panic and people turned to different things in order to find a reason. Some of the reasons were the planets lining up, God, or the Jews. Some people went through extreme measure of whipping themselves in an attempt to emulate Jesus. They also used methods such as quarantine which is a state of enforced isolations or cordon sanitaire which is a guarded line preventing anyone from leaving an area infected by the disease. People had to leave their families and the doctors stop seeing patients in fear of contracting the disease themselves. In todays society we have the modern version of the black plague. Most of the modern black plaque occurs in Madagascar today due to the poor hygiene and the piles of trash. They also have very hands on funeral rituals and up stealing the bodies after the hospital take them which causes more infections of the disease.

I learned from this class about the different diseases involved in the world throughout history. Diseases have developed and evolved to live in and adapt to our lifestyles. Everywhere you go there is some type of infectious bacteria or virus. People die every day from diseases and in a lot of cases those diseases could have been prevented. There are social and cultural issues that typically go along with diseases. In some cases like AIDS people were less caring and helpful because of the negative stereotype and discrimination of gay people. New emerging diseases continue to be discovered the more we cut down forests, eat tainted meat, and come into contact with wildlife.

Yellow fever is a virus that is found tropical and subtropical areas such as South America or Africa (1). The virus is transmitted from person to person via mosquito (1). It however can’t be contracted through direct contact with someone infected (6). The virus normally spreads in the sylvatic cycle also known as the jungle cycle but if this gets into the Aedes mosquitos it can create a hard to contain urban version of the yellow fever (4). Most of the time it gets transmitted from monkey to monkey but rarely it can infect a human (4). Symptoms take 3-6 days to develop which can include fever, chills, headache, backache, and muscle ache (2). Approximately 15 percent of those who get yellow fever develop severe symptoms such as bleeding, shock, organ failure, and possibly death (2). Yellow fever has a large range of severity ranging from a febrile illness to a severe liver disease with bleeding (1). There is no actual treatment for the disease but there is a vaccination (1).

Yellow fever is cause by a 40nm to 50 nm wide enveloped RNA virus that is called Flavivirus (7). The flavavirus is 11,000 nucleotides long and has one open reading frame that encodes a polyprotein (7). The flavavirus infects monocytes, macrophages, and dendric cells as well as other things (7). The virus uses specific reptors to attach to the cells surface and gets taken up by the endosomal vesicle (7). When it gets inside the endosome it reduces the PH and causes the fusion of the endosomal membrane and the virus envelope (7). After that the capsid enters the cytosol, decays, and releases genome (7). After the virus enters the host cell the virus begins making copies of itself inside the rough endoplasmic reticulum (7).

Currently Brazil is going through an ongoing outbreak of yellow fever. The first cases were spotted in December 2016 in Minas Gerais (2). Since then there have been reported cases in the surrounding areas such as Espirito Santo, Sao Paulo, and Rio de Janeiro (2). Since March 16, 2017, the yellow fever has been spreading to the Atlantic coast of Brazil in places that were not thought to be at risk for yellow fever (3).  They updated the travel notice to level 2 which means you should practice enhanced precautions when visiting Brazil (2). It is recommended that anyone older than 9 months old should get vaccinated and those without the vaccination should stay away from these areas (2). If you are traveling to one of these areas, it is recommended that you get a vaccine or booster 10 days before your trip (2). It is also recommended that you prevent mosquito bites using long sleeved clothes, bug spray with DEET, sleep in screen or air conditioned rooms, and use a bed net (2).

The International Coordinating Group on Vaccine Provision has approved the release of over 3.5 million doses of vaccine (4). The yellow fever vaccine provides up to 99% immunity but the vaccines take a long time to produce and they don’t have many of them in storage (5). Currently the country is already one of the top yellow fever vaccine manufacturers in the world (4). Normally Brazil would be able to take care of its own vaccinations but there has been a big increase in the number of people found with yellow fever (4). More than 30 million people were vaccinated in the emergency vaccination campaigns in Angola and the Democratic republic of Congo in 2016 (5). As the vaccines ran low they had to decrease the dosage to a fifth of its original amount so they could get it to more people (5). Brazil has distributed 12.5 million doses of the vaccine but it is hard to get it to everyone because some people live in dispersed remote areas away from the general population (5). They are also controlling the population of mosquitos there to prevent the spread through vector transmission (5).

Since March 13 there has been 1,538 reported cases and 255 deaths from yellow fever (4). So far the World Health Organization said that there is no evidence saying that the Aedes Mosquitos are spreading the virus (4). The current outbreak is reported to be spread by the Haemagogus and Sabethes mosquitos (5). The fatality rate for the outbreak of yellow fever is 33% for confirmed cases and 11% for suspected cases (5).

This disease has the potential to cause serious problems to a country especially if it gets into the Aedes mosquito and can spread from human to human rapidly. With the virus using the Aedes mosquito as a vector it has the potential to spread through Americas east coast rapidly if someone somehow gets infected and get bitten by the mosquito. Fortunately though we have a yellow fever vaccine to combat the disease and prevent the excessive spread of the disease. The issue right now in Brazil is being able to get the vaccine to everyone because of how spread out people are throughout the country. Ways to avoid being infected are mostly vector control and avoidance because other than mosquitos it is hard to get this disease. Once again mosquitos cause the spread of another disease so the best way of eradicating this disease as well as many other diseases in my opinion would be wiping out the mosquito population. The main issue I can think of with eradicating mosquitoes is the impact it would have on any animals that feed on them.

Citations

1. https://www.cdc.gov/yellowfever/
2. https://wwwnc.cdc.gov/travel/notices/alert/yellow-fever-brazil
3. http://www.who.int/csr/don/20-march-2017-yellow-fever-brazil/en/
4. https://www.statnews.com/2017/03/21/brazil-yellow-fever-vaccine/
5. http://www.cnn.com/2017/03/09/health/yellow-fever-outbreak-brazil/
6. http://www.medicinenet.com/yellow_fever/page4.htm

7. https://en.wikipedia.org/wiki/Yellow_fever

Transmission of cholera is typically through the fecal oral route. This was a problem because people didn’t have very good sanitation in poorer countries which allowed the disease to spread. The disease spread through the water because people went to the bathroom next to the water which infected the streams. The water was used as the main water supply for the villages. Then anyone infected with the disease could infect anyone that came in contact with anything their infected hands touched mostly food.

The reason this isn’t a problem in more developed countries is because of technology and knowledge about how infectious diseases are spread. One invention that prevents the spread of cholera is the toilet and sinks. This allows people to keep their fresh water away from their waste water. John Snow was one of the people who gave us the knowledge we have today about cholera. John Snow was able to trace cholera back to water and waste in London. This led to and overall change in this city as well as other cities and allowed for a change in public health overall. Whitehead worked with snow to prove that the Broad street pump was the source of the cholera infections. Robert Koch is the one who is credited as being the first one to identify the disease while Filippo Pacini was completely ignores when he tried to tell people of the disease. These guys completely changed the way we look at germs and sanitation as well as increase the amount of knowledge on infectious diseases.

In the fall of 2010 after the earthquakes, cholera began to spread in Haiti. The cholera spread from a United Nations Peacekeeping camp in Haiti. The disease was brought over from Nepal when Nepalese peace workers were staying at the United Nations camp and due to poor sanitation, the sewage went straight into the local waterways. They have quarantined patients with the disease and treated them for cholera. They have yet to put in a new national water and sanitation system or to pay for any damage they caused.

Tuberculosis is a debilitating disease caused by the bacteria Mycobacterium tuberculosis. Tuberculosis affects the lungs for the most part but it also affects the kidneys, bones, lymph nodes and brain. Most infections are latent TB which means that they don’t show symptoms and can’t spread to other people. About 10% of those with latent TB can progress to the active disease which if left on its own kills about half of those infected. The main cause of TB is an aerobic nonmotile bacillus. HIV is a risk factor of TB, 13% of all people with TB also are infected with HIV. HIV is a huge problem in Africa which is why the disease is so prevalent in Africa. It is also linked to overcrowding and malnutrition which is why it is also more prevalent in poorer areas. People who have active pulmonary TB can infect others through coughing, sneezing, or anything else that allows droplets to come from their mouth. When TB is called a social disease, it means that it is spread through contact with others. This is a problem for people in Africa because people are a lot closer. Africans are very social people who interact constantly with each other. If someone is sick with TB you are unable to help that person or be at risk for the disease. To eradicate this disease, you must prevent other people from coming into close contact with those who are sick. This can be difficult especially in 3^rd world areas where people are packed together in houses, on the streets, and on buses.

Potatoes became a staple crop in Ireland because they are high in protein, vitamin and complex carbohydrates. This made the Irish population grow tremendously. From 1780 to 1840, the Irish population doubled from 4 million to 8 million. The regular Irish peasant ate from eight to 14 pounds of potatoes every day. Then the potato blight hit caused by the pathogen Phytophthora infestans and wiped out the potatoes quickly. The leaves all turned black and the stems, roots and tubers blackened from rot. The blight originated in the remote Mexican valley and spread throughout Western Europe in 1845. The potatoes that were resistant to the blight were later used in producing new potatoes that were resistant to the blight.

Now we have genetically altered food using Talen or Crispr. Talen is a restriction enzyme that can be engineered to cut specific sequences of DNA. Crispr are segments of prokaryotic DNA sequencing that are used for gene removal or addition. GMO stand for genetically modified organism which are created through laboratory process where genes from the DNA of a species is put into the genes of another. Often when people hear the word GMOs they are quick to reject it. Within 9 years after GMOs were introduced the percentage of Americans with three or more chronic illnesses jumped from 7% to 13% but there is no evidence that is linked to GMOs. Research across the world indicated that there was no relation between GMOs and mutations in our genes. Fertility, pregnancy and offspring are unaffected by GMOs. Organ health and function was also unaffected.

Smallpox is a dangerous and debilitating disease that is known for the small pockes full of puss. Smallpox used to be the major killer of babies. Smallpox is transmitted through face to face contact, body fluids, scabs, contaminated objects, and airborne transmission. Even if someone survived this disease they were covered in scars afterward. This disease swept over the entire world and killed hundreds of millions of people over the centuries. In just the 20^th century by itself it caused the death of about 300 million people. In living in an area of a smallpox epidemic it would be normal to see the disease in almost everyone. The only thing left to do is to pray that you don’t die from the disease yourself. I can imagine there was a lot of fear during this time not knowing who was going to die next.

During that time, they had very primitive healing techniques because they didn’t understand how the disease worked such as bloodletting, leeches, fasting, laxatives, purgatives, diuretics, sweat therapy, and cold therapy. A lot of these “treatments” ended up hurting the patient instead of helping them. The first person to create a real vaccination for this disease was Edward Jenner. He used the infection of cow pox to use as a vaccine for smallpox. After that it became widespread to everyone. Even the possibility to a cure to this dangerous disease made it worth getting. The vaccine was distributed through orphans to carry it around from place to place.

The objections were that it interfered with Gods plan, smallpox reduces the poor population, and they didn’t know how safe the vaccine was. Vaccines became the better choice due to the prevention of bloodborne illnesses. The World Health Organization started a global effort in eradicating the disease through international reports. They also used selective control to prevent mass contamination. Problems with this include adverse reaction to the vaccine and being able to find those people contaminated before they contaminated anyone else. Eventually the disease was completely eradicated globally.

Syphilis is a sexually transmitted disease that causes ulcers, rashes, and even death if not treated. Patients look to doctors to cure them of illnesses they are unable to cure themselves. When a patient comes to a doctor the patient is putting his/her life into their hands. So, when a doctor does something or doesn’t do something to help that patient, it leaves mistrust between the relationship of doctor and patient. In the Tuskegee Syphilis Study and Guatamala venereal disease study the doctors claimed they were helping them when instead they were doing nothing for them. Even if it was for the sake of research patients have every right to know what is going on.

The rational behind the neglect of the African Americans was to see how syphilis progressed through the body. After this experiment the amount of mistrust among the African American population regarding doctors spiked. Poorly conducted experiments like this one could potentially affect other patient’s willingness to join these types of experiments and it also could create a distrust in the medical profession in general.

The Black Plague has occurred in three waves throughout history. The first was known as the Justinian plague in 542 AD, the second and more famous of the three is the Black Death, and the third is the modern or bubonic plague. Humans were first infected with the Yersinia pestis inside of fleas on rats. The disease is believed to have started between India and China. The incubation period of the bubonic plague is 1-3 days. The infection can be spread through the blood or it can reach the lungs. If the disease reaches the lungs, then the disease can be spread person to person through the air by coughing. The Mongols spread the disease around through their conquest. A major reason to why it was spread so easily was the amount of trade that went on during this time. The city was densely populated so it only took one person with the plague to infect multiple people to start an endemic in that area.

The societal response to the situation was panic. People were dying in large numbers and the people had no idea what the cause of the disease was. People started looking into things to blame for the disease such as the planets lining up, God, or the Jews. Some people tried to fix the problem through self-whipping in attempt to emulate Jesus. They also used other methods such a quarantine which is a state of enforced isolation or cordon sanitaire which is a guarded line preventing anyone from leaving an area infected by the disease. The plague had an impact on the society and culture as well. Some people abandoned their family members to the disease and doctors stopped seeing patients in fear of contracting the disease. The Jews were treated with resentment and were villainized which started the slaughter of Jews throughout Europe in spite of them dying in about equal numbers to everyone else. Some people became more religious while others had their religion conflicted.

In today’s society we know a lot more about the plague and how it is transmitted. The plague in the US mostly occurs in more rural areas. There is a large amount of rodent species that can get the plague as well as some carnivores that eat these rodents such as cats. The infected animals serve as long term reservoirs for the bacteria. If a case does get reported they will isolate that person away from everyone else and bury the bodies to prevent contamination to someone else. The disease is still pretty serious in Madagascar due to the poor hygiene and the interesting burial practices they have there. Rats are also very common in Madagascar due to the loads of trash piles they have there. The hospital doesn’t let the family take back the body of the deceased so it doesn’t infect them which results in people not bringing them to the hospital in the first place or stealing the dead body.

Back during the hunter gatherer times, the people were less exposed to rotting meat and night soil due to their constant moving so they weren’t as exposed to parasites. The tribes were also relatively small so they didn’t have the opportunity to pass on diseases to lots of people. They did however get intestinal worms, lice, fleas and they also sometimes encountered microbes from some of the wild animals they encountered. From 8000 BCE to 1750 CE the population grew 160 times to about 800 million. As the population increased they began to increase in agriculture which led to denser populations. People staying in one place meant that people could reproduce faster which required more food. This meant they had to improve the production of food and livestock. Because of this the humans and animals shared the same water supply and the conditions for the villages were a nesting site for rats, mice, ticks, flies, and mosquitoes. There were upsides to animal domestication such as food, material for clothing, fertilizer, land transportation and labor. But animal domestication also is a popular source for human diseases. The major diseases that ended up killing a lot of people came from evolving animal diseases. As humans expanded they also cleared out forests which killed animals and allowed for the spread of insects and rodents.

If you look at dates of the most common infectious diseases today, they are all relatively recent. The forests are continually being cleared out for resources and farmland which continues the disease problem. The ditches and irrigated fields serve as breeding ground for insects and other parasite harvesting organisms. The consumption of bush meat has also been a big issue when it comes to the spread of disease due to the availability of the meat and the disease potential the meat has. The direct movement of people into habitats with bush mean may have contributed to the emergence of Ebola and Aids. The spread of these diseases over wide areas is a modern day issue due to how easy it is for someone to fly from one country to the next. Modern farming practices in association with trade travel, and ecological change are responsible for the emergence of some diseases such as mad cow disease, foot in mouth disease, and Nipah virus.

As the population has been increasing our climate change potential has also been increasing more people means more strain of the environment such as soil exhaustion, water depletion and the loss of various species of wild animals and plants. The primary cause of climate change is due to global warming because of greenhouse gas emissions from cars and factories. This process of global warming is also enhanced by the negative feedback loop escalating the rate at which this is occurring. The primary risk to health due to climate change is the direct biological consequence of heat waves, extreme weather events, and temperature enhancement due to air pollutants. The secondary risks affect the amount of food, water flow, infectious disease vectors, and immediate host ecology for zoonotic diseases. The tertiary risks include the consequences due to the decline of basic resources.

In this class I have learned about the anatomy of the human body, difference between the words sex and gender, and what it means to not follow the gender roles. But more importantly I have learned about discrimination based on gender and how different cultures treat different genders. A lot of the discrimination I learned about is due to cultural and religious attitudes which makes it harder to bring about a change.

Sex is defined as the genetic difference in a species which characterises them as being either male, female, or other (Artifact 1). Gender is different in that it doesn’t so much look at the genetic difference but the social difference which is more based on physical appearance (Artifact 1). Gender has a number of forms to it such as the psychological side which is how the boy or girl feels, the social side which are the beliefs that are held and the responsibilities that come with it, and the behavioral side which is how a boy or girl dresses and acts (Artifact 1). Often parents try and conform their kids at an early age to what they believe their gender should be by giving them clothes and toys that are supposed to belong to their sex. Because of this notion of global gender roles people who do not follow the gender stereotypes are ridiculed.

Another issue is the gender gap in society which typically affects women around the world in different ways (Artifact 2). The gender gap can affect whether a woman can get a job or and education and can even be dangerous. According to data the United States is pretty good when it comes to discrepancy of education but in places like India and most of Africa have more than a 16 percent difference between male and female secondary education levels (Artifact 2). This is an issue that is harder to fix because of noticeable differences in strength and speed, pregnancy, and genitalia (Artifact 2).

India has a very noticeable difference in gender gap between males and females (Artifact 3). Women in India are seen as subservient to men and are meant to do the housework (Artifact 3). When women violate these roles that are given to them they are often subjugated to threats, harassment, and murder. These negative feelings towards women causes the abuse and neglect of girls through insufficient feeding and ignoring illnesses (Artifact 3). Now that there is ultrasound which can determine the sex of the baby inside the womb the rate of abortion of female fetuses has increased in spite of the laws against it (Artifact 3).

Often when people think of gender they think of either male or female but in reality there are others that do not fit into these categories. Transgender is when a man is turned into a woman or a woman is turned into a man. For a transgender in the United States life is hard, transgenders have a 1 in 12 chance of getting murdered and on top of that they have a 49 percent chance of committing suicide (Artifact 4). Sweden is trying to take steps to avoid this discrimination by creating a gender neutral environment (Artifact 4). Different cultures look at gender in different ways, while some condemn it in other countries it is very accepted (Artifact 4).

Another problem is with the gender health gap in that the model of women is based off of men. Men and women are both externally and internally different so it makes sense that there are at least a few differences in health and diseases between men and women (Artifact 5). When it comes down to it women are actually better at surviving when it comes to health (Artifact 5). Men and women do share 22 chromosomes together but the last pair known as the sex chromosome which is why men and women are so different (Artifact 5)

Males and females go through a process of genital cutting known as circumcision (Artifact 6). In males this process of genital cutting has health benefits but for females it has no benefits and can be harmful or dangerous for them (Artifact 6). The circumcision for males is the removal of the foreskin that is over the penis (Artifact 6). This circumcision for males is done in most countries right after the baby is born and it has a considerable amount of benefits. Some of the benefits include reduced risk of urinary tract infection, prostate cancer, sexually transmitted diseases, and reduced risk of cervical cancer (Artifact 6). The female circumcision on the other hand is dangerous and in these regions it is often done with unclean items which increases the transmission of diseases (Artifact 6). The reason that these harmful circumcisions occur is usually for cultural or religious reasons and because of that it is harder to get rid of especially when the religious leaders still want it.

Menstruation is something that separate women from men and is often looked at in a negative way. In reality menstruation is perfectly natural and is the time when a woman shed the lining of her uterus (Artifact 7). But still menstruation is seen with negative feelings because it is something that only women have, so men are unable to understand what they are going through. In foreign countries menstruation is seen as an abnormality or something that should be avoided (Artifact 7). In foreign countries women actually are forced out of the house live in little huts during their period. This fear is linked with a lack of understanding as well as religion and tradition (Artifact 7). If men had periods as well this wouldn’t even be an issue but because this is only done by females it is seen as gross and unnatural.

Women in general are discriminated against a lot throughout the world, in some places more than others. I feel that if women were the genetically stronger species that the roles would have been reversed. What is important now is closing the gender gap between males and females and I feel that can be done through education. Older people tend to be more stubborn when it comes to changing their values so in order to bring about a change the newer generations have to be the ones to implement this change in thinking.