The virus Orthopoxvirus variola is the causative agent of smallpox, a dangerous infectious disease that is believed to have been around for thousands of years. The name smallpox means blister or pocket and refers to the skin lesions that are one of the most obvious symptoms of this disease.
What is orthopoxvirus variola?
Human smallpox virus (Orthopoxvirus variola) is believed to have been first identified around 1906 by Enrique Paschen, a Mexican-German vaccinator. He succeeded in discovering the so-called elementary corpuscles in the lymph fluid of an infected child with the aid of an optical microscope, which were named after him as Paschen’s corpuscles. However, the ancient Egyptians already knew about this disease. They called it Uhedu disease. In ancient China, at the time of the construction of the Great Wall, people spoke of Hun pox, and the ancient Romans called smallpox Antonine plague. In addition to true smallpox (variola major or variola vera), there is also white smallpox (variola minor) and East African smallpox, also known as black smallpox. In addition to these human smallpox viruses, there are also various animal smallpox viruses, such as monkeypox, cowpox, and camelpox, which can also be transmitted to humans via the relevant intermediate hosts.
Occurrence, distribution, and characteristics
Smallpox has repeatedly caused devastating epidemics in the past, killing millions of people. They were considered one of the biblical plagues, ravaged the Roman Empire for decades, wiped out parts of the indigenous peoples of the Americas, Africa, and Australia, and probably came to Europe with the Crusaders. At that time, an estimated 400,000 people died here every year as a result of the disease. At times, the number of smallpox patients and fatalities even exceeded the numbers of plague or cholera deaths. Famous personalities in history such as Luis XV, King of France and Navarre or the Russian Tsar Peter II died of it. Beethoven was probably deafened by smallpox, and Josef Haydn’s face was disfigured by smallpox scars. From the beginning of the 19th century, smallpox vaccinations with live vaccines were available, which quickly succeeded in repressing smallpox. The number of new infections fell. In 1967, the World Health Organization (WHO) began a worldwide campaign to eradicate smallpox, a general vaccination requirement was introduced, and in 1980, the WHO determined that the smallpox virus could be considered virtually extinct. As a result, general smallpox vaccinations were again abolished. However, there is still a stockpile of vaccines in many countries of the world (including Germany) for the prevention of possible smallpox outbreaks and for the early treatment of groups of people who may be at risk or infected.
Diseases and medical conditions
The last recorded cases of human smallpox occurred in Bangladesh in 1975, in Birmingham in 1978, and in Somalia. However, at least in the United States and Russia, there are still research facilities that store smallpox viruses today. Since the discontinuation of smallpox vaccinations, the number of people contracting monkeypox (orthopoxvirus simiae) or cowpox (orthopoxvirus bovis), for example, has increased, especially in Africa. Previously, these types of smallpox did not occur in vaccinated individuals because of so-called “cross-infection protection.” In addition, some researchers fear that the animal smallpox species may also mutate over time, making human-to-human transmission more likely. Human smallpox virus is theoretically transmissible by droplet infection from coughing and sneezing, but also by inhalation of dust from infected bedding, clothing, dishes, or other objects with which the ill person has had contact. Laboratory accidents are also possible. Monkeypox can be transmitted to humans when infected rodents, rats, or monkeys bite or scratch people, or when people consume the flesh of infected animals. Cowpox and camelpox are transmitted in part during milking. The incubation period of smallpox virus averages 2 weeks. At the onset of the disease, there is a severe feeling of illness. Affected individuals have high fever, chills, headache, aching limbs, sore throat, and swollen lymph nodes. The fever generally progresses in two episodes; after the second episode, the skin changes typical of smallpox occur.The pustules and skin blisters spread mainly on the face, neck, chest, groin region and feet. When the pustules dry up and fall off after weeks, they often leave behind skin dimples or pockmarks. If the course of the disease is particularly severe, it can also lead to terrible sequelae such as paralysis, brain damage and blindness. However, milder courses are also common. The risk of infection with smallpox is very high. Treatment options are limited to strict bed rest, antipyretics and painkillers, and treatment of secondary diseases. In the past, a large proportion of people who contracted smallpox died. In the 20th century, the mortality rate was about 30 percent. The disease particularly affects patients with weakened immune systems, the elderly and children. Among people infected with animal pox, the mortality rate is much lower, at about one percent. Those who survive smallpox are subsequently resistant and thus protected from the disease for life.
