A deadly virus is returning. Scientists estimate smallpox pandemic risk

For the first time in twenty years, a case of human infection with monkeypox has been reported in the United States. An American who traveled to Nigeria contracted the disease. Such cases could cause a new pandemic, as mankind has no collective immunity against smallpox (abandonment of mass vaccination occurred forty years ago).

There have been times when smallpox has decimated entire countries. For example, when smallpox was introduced into the Americas, it severely affected the native inhabitants and contributed to the fall of civilizations in Mexico and Peru. Smallpox is provoked by the orthopoxvirus, which is transmitted by airborne droplets. For the first two weeks after infection, the disease develops stealthily, then an acute period begins that leads to recovery or death. The patient is covered with purulent pustules that leave behind a lifelong scar, if the person manages to survive.

Smallpox has been a companion of mankind since Ancient Egypt, so people have learned to fight it over thousands of years. In China, young children had dried pustule crusts blown into their noses, infecting them with the virus. About two percent of the children died, but the rest gained lifelong immunity. In the late eighteenth century, the English physician Edward Jenner invented vaccination by inoculating a child with the contents of a pustule from the hand of a milkmaid who had contracted cowpox.

Today, when smallpox is considered a completely defeated virus, kept only in super-protected laboratories, the threat of a smallpox pandemic has been forgotten. However, sporadic cases of monkeypox, which are recorded from time to time in the world, cause some concern among experts. Scientists believe that the pathogen could mutate and become more infectious.