Final answer:
Smallpox, caused by variola viruses, was a severe and contagious human disease eradicated in 1979 through a global vaccination campaign. Early practices of inoculation evolved into vaccination, which uses a weakened form of the virus to build immunity. The concerted efforts in vaccination led to the complete eradication of smallpox, highlighting a landmark success in medical history.
Step-by-step explanation:
The Eradication of Smallpox
Smallpox has been a severe contagious disease that was successfully eradicated in 1979 after a rigorous global vaccination campaign by the World Health Organization. The disease, exclusive to humans, was caused by the variola viruses and its elimination from nature marks a pivotal achievement in medical history, as humans were the sole carriers of the virus. Despite the severe impact of smallpox throughout history, with fatality rates higher than 50%, the dedicated effort to vaccinate and control the disease led to its eradication, making it the first human infectious disease to be completely wiped out.
The early practice of inoculation, which involved introducing a small amount of the virus to build immunity, played a significant role in the fight against smallpox. The method, adopted in Europe in the 18th century from the Ottoman Empire, evolved into the modern concept of vaccination. It laid the groundwork for vaccines consisting of weakened or inactivated pathogens to stimulate the immune system without causing severe illness.
The safe practice of inoculation and subsequent vaccination efforts enabled the control of the smallpox virus, which was highly contagious through respiratory secretions, skin rash, or eye secretions of the infected individual. Despite variolation's success in reducing mortality rates compared to natural infections, it possessed inherent risks, which were eventually mitigated through the development of more sophisticated and safer vaccination methods.