History Epidemics Introduction.

Human history can also be described as Epidemics history. The earliest recorded epidemic is the Plague of Athens in 430 BC which killed 25% of the population. From that time, human beings have experienced bubonic plague, smallpox, cholera, malaria, tuberculosis, yellow fever and so on. Billions of people died during epidemic breaks. Throughout human history, until the twentieth century, and still today in the twenty-first century in the developing world, infectious diseases have been the most important cause of suffering and death. This page will introduce epidemics mentioned above, including their pathogens, symptoms and transmission methods.

History Epidemics Gallery

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Plague bacterium: Yersinia pestis
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Plague: distribution of plague infected animals 1998
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Plague symptom: swollen inguinal lymph glands
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Smallpox: viruses
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Smallpox symptom: rash
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Cholerae bacterium: Vibrio cholerae
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Cholerae symptom: severe dehydration
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Malaria pathogen: Malaria parasite
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Malaria: main symptoms
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Tuberculosis bacterium: Mycobacterium tuberculosis
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Yellow fever virus
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Yellow fever symptom: jaundice

Plague pathogen: Yersinia pestis
Plague: distribution of plague infected animals 1998
Plague symptom: swollen inguinal lymph glands
Smallpox: viruses
Smallpox symptom: rash
Cholerae bacterium: Vibrio cholerae
Cholerae symptom: severe dehydration
Malaria pathogen: Malaria parasite
Malaria: main symptoms
Tuberculosis bacterium: Mycobacterium tuberculosis
Yellow fever virus
Yellow fever symptom: jaundice

Bubonic Plague

Bubonic Plague has historically occurred in large outbreaks, with the best known being the Black Death in the 14th century, which resulted in greater than 50 million deaths.

Pathogen
Bacterium Yersinia pestis.
Symptoms
Following an incubation period of 1-7 days, patients develop sudden onset of fever, headache, chills, and weakness and one or more swollen, tender and painful lymph nodes.
Transmission
  • Droplet contact – coughing or sneezing on another person.
  • Direct physical contact – touching an infected person, including sexual contact.
  • Indirect contact – usually by touching soil contamination or a contaminated surface.
  • Airborne transmission – if the microorganism can remain in the air for long periods.
  • Fecal-oral transmission – usually from contaminated food or water sources.
  • Vector borne transmission – carried by insects or other animals.

Smallpox

Smallpox, eradicated in 1980, ever succeeded plague as the most feared disease in the eighteenth century. It killed around 500 million people in the last 100 years of its existence and and produced blindness, disfigurement and maiming on survivals.

Pathogen
Variola major and Variola minor.
Symptoms
Following an incubation period of about 12-14 days, there is a sudden onset of influenza-like symptoms including fever, malaise, headache, prostration, severe back pain and, less often, abdominal pain and vomiting. Two to three days later, a characteristic rash appears, first on the face, hands and forearms and then after a few days progressing to the trunk.
Transmission
Smallpox is transmitted from person to person by infected aerosols and air droplets spread in face-to-face contact with an infected person. It can also be transmitted by contaminated clothes and bedding, though the risk of infection from this source is much lower.

Cholera

In nineteenth century, Cholera began its devastating international career, including seven large outbreaks with millions of deaths. Nowadays, it still affects 3–5 million people worldwide.

Pathogen
Vibrio cholerae.
Symptoms
It can take anywhere from a few hours to 5 days for symptoms to appear after infection. The infection is often mild or without symptoms, but sometimes it can be severe and life threatening. Approximately one in ten (5-10%) of infected persons will have severe cholera which in the early stages includes:
  • profuse watery diarrhea, sometimes described as "rice-water stools".
  • vomiting.
  • rapid heart rate.
  • loss of skin elasticity.
  • dry mucous membranes.
  • low blood pressure.
  • thirst
  • muscle cramps
  • restlessness or irritability
Transmission
Cholera has been found in two animal populations: shellfish and plankton. Transmission is usually through the fecal-oral route of contaminated food or water caused by poor sanitation.

Maliaria

Maliaria is an epidemic disease with long history. Malaria may have contributed to the decline of the Roman Empire, and was so pervasive in Rome that it was known as the "Roman fever". In 2016, there were 216 million cases of malaria worldwide resulting in an estimated 445,000 to 731,000 deaths.

Pathogen
Malaria parasite.
Symptoms
Symptoms of malaria include fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Malaria may cause anemia and jaundice (yellow coloring of the skin and eyes) because of the loss of red blood cells. If not promptly treated, the infection can become severe and may cause kidney failure, seizures, mental confusion, coma, and death.
Transmission
Usually, people get malaria by being bitten by an infective female Anopheles mosquito. Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery.

Tuberculosis

Tuberculosis(TB) has existed since antiquity. Skeletal remains show some prehistoric humans (4000 BC) had TB, and researchers have found tubercular decay in the spines of Egyptian mummies dating from 3000 to 2400 BC. Nowadays TB is one of the top 10 causes of death worldwide. In 2018, 10 million people fell ill with TB, and 1.5 million died from the disease.

Pathogen
Mycobacterium tuberculosis.
Symptoms
Symptoms of TB disease depend on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs (pulmonary TB). TB disease in the lungs may cause symptoms such as
  • a bad cough that lasts 3 weeks or longer.
  • pain in the chest
  • coughing up blood or sputum (phlegm from deep inside the lungs
  • weakness or fatigue
  • weight loss
  • no appetite
  • chills
  • fever
  • sweating at night
Transmission
TB is spread from person to person through the air. When people with lung TB cough, sneeze or spit, they propel the TB germs into the air. A person needs to inhale only a few of these germs to become infected.

Yellow Fever

Yellow fever is also an epidemic disease with long history. It was endemic in Africa before. The virus was probably transferred to North and South America with the importation of slaves from Africa. At least 25 major outbreaks took place in the Americas during the 18th and 19th centuries. Nowadays, yellow fever is endemic in areas of Latin America and Africa. The disease infects about 200,000 people per year and kills 30,000 people globally each year.

Pathogen
Yellow fever virus, an enveloped RNA virus.
Symptoms
Yellow fever begins after an incubation period of three to six days. Most cases only cause a mild infection with fever, headache, chills, back pain, fatigue, loss of appetite, muscle pain, nausea, and vomiting. In these cases, the infection lasts only three to four days. While in 15% of cases, people enter a second phase of the illness after a remission. This second phase includes a return of high fever, as well as jaundice; abdominal pain and vomiting; bleeding from the mouth, nose, eyes, or stomach; and deteriorating kidney function. As many as half of the patients who experience the second phase may die.
Transmission
Yellow fever virus is mainly transmitted through the bite of the yellow fever mosquito.