Varíola - a incrível história da doença que morreu - Fisiologia Humana

Summary

The video discusses the devastating impact of smallpox, a viral disease that claimed over 300 million lives in the 20th century alone. It explains the virus's origins, its two forms (minor and major), and how it spread, primarily through respiratory droplets. Despite its high fatality rate, individuals who survived developed lifelong immunity, leading to the practice of variolation, and later, vaccination. The breakthrough vaccine, developed by Edward Jenner in 1796 using cowpox, led to the eventual eradication of smallpox, with the last case occurring in Somalia in 1977. The video highlights the disease's history and the efforts that led to its global elimination.

Takeaways

• 😀 Smallpox caused over 300 million deaths in the 20th century, surpassing the combined death toll of both World Wars.
• 😀 Smallpox had two forms: variola minor (less severe, 1% fatality rate) and variola major (more common, 20-30% fatality rate).
• 😀 Smallpox left survivors with lifelong scars, deformities, and sometimes blindness, with severe outbreaks often leading to death from complications.
• 😀 The smallpox virus originated from a rodent-borne virus in Africa about 15,000 years ago and spread over centuries.
• 😀 Ancient Egyptians had documented smallpox cases as early as 1150 BCE, and smallpox was spread through Europe and the Americas in the 16th and 17th centuries.
• 😀 The disease was primarily spread via respiratory droplets from coughing, sneezing, and infected bodily fluids.
• 😀 The incubation period for smallpox was 10-14 days, with symptoms like high fever, headache, and a distinct rash appearing later.
• 😀 Survivors of smallpox developed lifelong immunity, leading to the concept of variolation, an early method of providing immunity.
• 😀 Variolation, practiced in China and India, involved using material from smallpox sores to induce a mild infection as a form of immunity.
• 😀 Edward Jenner’s 1796 discovery of the cowpox vaccine marked the beginning of smallpox vaccination, leading to global eradication in the 20th century.

Q & A

What were the two main forms of smallpox, and how did they differ in severity?

The two main forms of smallpox were Variola minor and Variola major. Variola minor was rarer and milder, with a mortality rate of about 1%, while Variola major was more common and much more severe, killing 20-30% of those infected.

What were some common complications associated with smallpox?

Common complications included bacterial infections of the skin lesions, arthritis, pulmonary edema, pneumonia, encephalitis, and acute stomach dilation, particularly in children. In fatal cases, death typically occurred 10 to 16 days after the onset of symptoms.

How did smallpox spread, and what were the main sources of infection?

Smallpox spread through respiratory droplets, with nasal and mouth secretions being the primary sources of infection. It could also be transmitted by direct contact with material from skin lesions, particularly in the later stages of the disease.

What did the historical presence of smallpox look like in ancient civilizations?

Smallpox was likely present in ancient civilizations, with evidence such as skin lesions on Egyptian mummies dating from 1580 BC, suggesting that Egypt was one of the earliest places to document the disease.

How did the European colonization impact the spread of smallpox?

During the 16th and 17th centuries, smallpox spread to the Americas due to European colonization, causing a devastating impact on native populations who had no prior exposure or immunity to the virus.

What was the process of variolation, and where did it originate?

Variolation was an early form of inoculation to prevent smallpox, where material from smallpox sores was introduced into the skin of healthy individuals. This practice originated independently in China and India before spreading to Europe.

What role did Lady Mary Montagu play in the spread of variolation in Europe?

Lady Mary Montagu introduced variolation to Europe in 1721 after she had survived smallpox and had her children undergo the procedure. Her efforts helped popularize variolation across the continent.

How did the discovery of cowpox contribute to the development of the smallpox vaccine?

The discovery that people who contracted cowpox, a milder form of the disease, were immune to smallpox led to the development of the first vaccine. Edward Jenner, in 1796, demonstrated that cowpox material could protect against smallpox by inoculating a boy with cowpox and then exposing him to smallpox.

What was the significance of the term 'vaccine' and its origin?

The term 'vaccine' comes from the Latin word 'vacca,' meaning cow, as the first smallpox vaccine used cowpox material. The word 'vaccination' was adopted in 1803 to describe the procedure of using cowpox to prevent smallpox.

How did the global vaccination efforts lead to the eradication of smallpox?

Global vaccination campaigns, using improved techniques and various methods of producing the vaccine, led to the eventual eradication of smallpox. The last known case of natural smallpox occurred in Somalia in 1977, and the disease was declared eradicated worldwide shortly after.