Yellow Fever: Symptoms, Transmission, Vaccinations

Introduction:

Throughout history many outbreaks of diseases occurred to leave behind them millions of dead bodies, some even went so far to taint the health of most of the population. Fear and agony were spreading alongside it, stealing children and loved ones and forcing people to immigrate out of this thought-to-be-cursed land …. I will be discussing the major, and most devastating epidemics across history, their causes, what lead to the spread of the disease in the first place, and what effects did each epidemic had brought with it.

Overview:

All huge outbreaks of lethal diseases in human history have been called plagues to emphasize how unpleasant and frustrating these outbreaks were. However, whenever actual bubonic plague makes its grand appearance, quarantine measures are issued, panic and stress spreads alongside the epidemic, and people flee the area. With its unfortunately high mortality rate and sadly rapid spread, bubonic plague remains one of the most severe outbreaks of disease the history has ever witnessed. Although plague is primarily a disease of rats and other tiny animals(zoonosis), especially fleas found on top of rodents, its effects on humans are significant and severe. Moreover, it has been spread widely by humans through the accidental transport of rats and their fleas. Finally, it has been intentionally exploited as a form of biowarfare since the first appearance of the Black Death in the Crimea, through World War II, and it may be used again in the future.

Save your time!
We can take care of your essay

• Proper editing and formatting
• Free revision, title page, and bibliography
• Flexible prices and money-back guarantee

Place an order

Symptoms:

Nowadays named bubonic plague because of the painful, swelled, abscessed lymph nodes (buboes), it produces, bubonic plague was also called the Black Death during a catastrophic pandemic in the mid-fourteenth century. The name most likely originated because patients with severe form of the disease developed septicemia, which is a widespread(systemic) contamination of the blood. This, in turn, leads to a syndrome formally known as disseminated intravascular coagulation (DIC), in which multiple hemorrhages and patches of gangrene develop in the skin, turning large areas of the body black.

Transmission and spread:

Bubonic Plague does not normally spread directly from person to person; its spread caused by small animal hosts, most of which rats and their fleas. Hungry fleas feed on diseased or rather infected rats, when these rats die, those fleas can hop on to a human host. Bubonic Plague can be spread directly from person to person when it leads to pneumonia(pneumonic plague) and, although the same little creatures that cause the bubonic form of the disease can result in pneumonia, severe lung disease does not occur often enough to rely on airborne pathogens to purposely spread the disease. If these bacteria-containing droplets are breathed in by another person they can cause pneumonic plague. Human-to-human transmission is rare and typically requires direct and close contact with the person with pneumonic plague. The septicemia that is found in tremendously sick patients can spread the disease without the assistance of rats. A flea directly feeding on the septic blood of a plague patient could pick up enough numbers of microorganisms to infect another human with its bite. Although primarily a disease of rats and other small mammals, and their fleas, bubonic plague is spread from location to other by human travel and commerce, a perfect route for the migration of the animal causatives of the disease.

Dr. Shibasaburo Kitasato apparently was the first to observe the bubonic plague up-close but published his findings in Japanese and English. Dr. Alexandre Yersin found the same microorganism and recognized its role, but he published his findings in French through a leading scientific journal of the time that quickly published short reports. hence, his work appeared first. Yersin’s priority of publication made him claim the credit of this amazing finding, and in 1970, the organism was named Yersinia pestis.

Even though the success of rat-catching campaigns, it is worth noting that reducing the rat numbers could have significantly increased the wide spread of plague, at least for a short time. eradicating rats minimizes the reservoir of infection, but leaves starving fleas looking for a brand-new source for their delicious bloody meal. Humans are the perfect alternate source of nutritious blood. Thus, humans are more prone to get infected by fleas bites as a result of the elimination of the rat population, at least until the population of infected fleas dies off. In many Middle Ages epidemics, the documents show that the finding of many dead rats in a community was almost immediately followed by outbreak of human cases of plague. (The New Mexican couple who recently became ill with plague in New York City had found a dead rat on their property just before leaving for New York, but they were not aware that they had been bitten by its fleas.

Vaccinations:

Catching the microorganism Yersinia pestis can be prevented in individuals through vaccination. However, vaccination can’t eradicate plague completely. Because of its rodent reservoir, the infection can rise again whenever unvaccinated individuals appear in a given vaccinated area. To prevent any cases of the disease One hundred percent of a population must be vaccinated. The vaccination of American troops in Vietnam stopped the spread of infection in the troops, but it did occur in the native population.

• Smallpox:
• Cholera:
• Coronavirus:

malaria and yellow fever:

overview:

At the time of the 1878 Memphis epidemic, the germ theory of disease was becoming accepted and the science of bacteriology established. However, the possibility of insect transmission of an infectious agent had not yet been demonstrated, and the concept was ridiculed. Malaria and yellow fever are two devastating diseases spread by the bite of specific species of mosquitoes.

malaria

even so treatment and prevention methods has been discovered since 1633, malaria cases are still showing worldwide and are a significant cause of death, mostly in youth. For along time, malaria was thought to have been the result of harmful emissions from decaying organic substance(miasmas). The observation that the most harmful emissions arose from swampy regions was based on the frequent occurrence of the disease near those areas. Because another name for such airborne toxic emissions were mal--aria or bad air, the term malaria used to refer to all diseases thought to be a result of miasmas.

Origin:

The first clue of malaria parasites was found in mosquitoes preserved inside an amber from the Paleogene period that are approximately 30 million years old. The malaria parasite is similar to one that affects Old World apes. The disease is thought to have widely advanced from the rain forest of tropical Africa, migrating slowly into the Nile Valley and the Fertile Crescent, and then to the northern shore of the Mediterranean. Despite that the evidence for the presence of malaria in Greece after 500 BCE is convincing, it is uncertain when it first appeared in that area. Evidence for malaria in ancient Egypt is much less abundant, but one very interesting possible example is the mummy of a weaver named Nacht, who was a servant of the Pharaoh Setnakht, first ruler of the twentieth dynasty.

Cause and symptoms:

The time the symptoms start to show up is based on the time it takes for the causative organisms to fully mature and breed in the red blood cells. Hence, once mature they cause the red cells to rupture, releasing huge number of tiny organisms into the blood, leading to fever and chills, therefore, permitting the organisms to enter other red blood cells and restart the cycle again. Statistically, the most common organism, Plasmodium vivax, takes about 48 hours to complete the cycle, and thus the fever and chills take place every other day (relapsing fever). This loop or cycle was called “tertian” by the Ancient Greeks. Thus, the following chill/fever took place on the third day of the new cycle.

Malaria today:

Malaria is still the most relevant parasitic disease affecting humans. Unfortunately, it is known to be present in ninety countries, with more than 300 million cases occurring each year, most of which are children. Factors unrelated to human activities can extend the disease, mostly wet climates, which greatly affects the breeding regions for the mosquito. Global warming may be a factor in proliferating the range of insect vectors and increasing the areas in which the vector can remain.

Yellow fever:

Although yellow fever has probably always existed in tropical areas of the ancient World, it did not appear in the Newspapers until the middle of the seventeenth century, it has probably originated across the Atlantic from Africa by the slave trade. Yellow fever lasted as an endemic in tropical areas of the Western Hemisphere and, away of those regions, it often led to problematic and severe summertime epidemics extended primarily by travelers.

Cause and symptoms:

Yellow fever is a widely spread infection, some form of viral hepatitis that causes massive death of the liver tissues and results in severe jaundice (which causes yellowish skin and mucus membranes), hence the name. The disease is propagated by a mosquito that can survive a whole year in tropical areas.

The observations of Dr. Carlos Finlay of Cuba had a great influence on the Reed Commission. Finlay, a native of Havana, had graduated from Jefferson Medical College in Philadelphia in 1855, then returned to Havana to practice. He was much loved and respected as a person and a physician, and despite his busy practice, he found time to study the problem of yellow fever and its transmission. He knew of the suggested vector role of mosquitoes and undertook an in-depth study of the mosquitoes of Havana. He recognized that only the female sucks blood from mammals. He showed that this occurred after fertilization by the male and that the warmth of the blood stimulated the female to ovulate. He postulated that the mosquito would prefer a patient with fever, since the warmer the blood, the sooner ovulation occurred. Thus, mosquitoes would be most attracted to patients with yellow fever, thus enhancing spread of the disease.

The patients suffer severe headaches, kidney abnormalities, and gastrointestinal hemorrhage that leads to vomiting of black material.

impact on modern medicine:

The control of yellow fever (and malaria) required proof of the mosquito’s role in the spread of disease, and the studies that established this role lead to some of the most dramatic and important episodes in the history of preventive medicine. The mortality rates for yellow fever were 30 to 50 percent, similar to the outbreaks of other deadly diseases such as smallpox, cholera, and even bubonic plague.