Smallpox is a disease that has accompanied humankind for a very long time. Genetic studies have placed the species transition, from small rodents to humans, between 10,000 and 50,000 years ago. We have found smallpox scars on mummies of pharaohs dating back to 1570 B.C., and Indian and Chinese texts from more than 3,000 years ago contain descriptions of the disease. The first recorded outbreak was in 1350 B.C., but many others followed in the long history of smallpox until 1980, when the WHO (World Health Organization) declared it officially eradicated.
It is a contagious disease of viral origin that is fatal in 30 percent of cases. It is characterized by the presence of pustules all over the body, which often leave disfiguring scars after healing, and it is from these that the name of the disease is derived: variola in Latin can be translated precisely as "pustule." Because it is a viral disease, there are no specific treatments and the use of antibiotics does not prove to be effective: the only real protection from smallpox is vaccination.
Given the eradication of the disease, mandatory vaccination has been suspended since the 1970s and 1980s in all countries. In Italy, vaccination was suspended in 1977 and finally repealed in 1981. To this day, specimens of the virus still exist, stored for study purposes under maximum security conditions in two laboratories, one in Russia and one in the United States.
Smallpox has played a pivotal role in the history of medicine: against smallpox, humanity's first attempts to achieve immunization without causing the disease were focused. First, with the technique of variolization, developed in medieval China and involving the exposure of healthy subjects to fluids and scabs of mild sufferers, and then with the creation of the first vaccine in history in 1976.
Variola major and Variola minor
Caused by Variola virus, of the genus Orthopoxvirus, the disease appears in two main forms. The most common is that caused by the Variola major strain of the virus, which manifests with high fevers and the appearance of ulcerating pustules all over the body. There are four such types of smallpox:
- Ordinary form (which makes up more than 90 percent of cases);
- Modified form, the symptoms are mild and sometimes develops on previously vaccinated people;
- Flat form (also called malignant);
- Hemorrhagic form, rare but very serious.
Less dangerous, with a mortality rate under 1 percent, is the form of smallpox caused by the Variola minor strain. Also called alastrim, from the Portuguese alastrar, meaning to spread, it presents in a significantly less severe form the same clinical picture as classical smallpox.
The manifestation and course
The incubation period of the disease, during which no symptoms occur, lasts from 7 to 17 days. Infection rarely occurs during this period, which instead begins when the first symptoms (fever, malaise, migraine, muscle pain, and sometimes vomiting) appear. This phase can last 2 to 4 days and is characterized by even significant hyperthermia. Thereafter, a very characteristic rash made of small red spots appears, and this is the period when sufferers are most contagious. The appearance of the spots can last about 4 days and starts on the tongue and mouth. When the mouth spots become infected becoming true ulcers, new rashes affect the whole skin, starting from the face to the arms, legs, and then the hands and feet. Usually the entire body is covered with spots within 24 hours. When the rash appears, the fever drops and the patient begins to feel better. Within 3 days, however, the spots turn into purulent blisters. At the same time, the temperature rises again and remains high until the pustules heal, becoming scabs that begin to scale and peel off.
Within 3 to 4 weeks after the onset of symptoms, most of the pustules have dried out and begin to peel away from the skin, leaving a deep scar on it, known as pockmarking. The infectious phase ceases as all the scabs fall off.
Other smallpox and scientific discovery
In addition to human smallpox virus, there is also cowpox virus (Cowpox virus), monkeypox virus, and vaccinia virus (Vaccinia virus). It was precisely the latter that was first used by English country doctor Edward Jenner in 1796 to formulate the first proper, smallpox vaccine. At that time the disease was having an alarming increase in Europe: in 1753 in Paris 20,000 people died of smallpox; in Naples in 1768 60,000 died in a matter of weeks; and every year due to the Variola virus England counted 40,000 deaths. Jenner noticed that milking women, who frequently contracted cowpox, were unlikely to be affected by human smallpox. To prove his theory, Jenner tried vaccinating an 8-year-old boy (legend has it that he was her son) with serum from cowpox pustules and then infected him with human smallpox, verifying his immunity.
This represents the first documented case of active prevention of a disease, although other attempts at immunization had already been made.
Indeed, in the late 1600s Lady Montagu, wife of the English ambassador to Constantinople, had also promoted the practice of smallpox immunization in England, following a custom already widespread in the East. The same practice had also been introduced in Italy by Greek physicians and supported by Pope Benedict XIV, who tried to spread it in the Papal States. Pitting consisted of injecting some pus taken from a sick person on the road to recovery, into a healthy subject causing smallpox. However, this practice was often lethal. Jenner's discovery solved the problem, although it was opposed by ecclesiastical and conservative circles because it was considered an insult to the creator, given the admixture of animal and human. With the prevalence of libertarian ideas in the years following the French Revolution, vaccination became a widespread practice.
Luigi Sacco and the spread of vaccination in Italy
In Italy, it was Luigi Sacco (1769-1836) who spread Jennerian vaccination. A physician in the Cisalpine Republic, he was born in Varese, graduated from Pavia, and was chief physician at the Ospedale Maggiore in Milan; in late 1799 he vaccinated himself and then five children with pus collected from two cows suffering from cow-pox. After some time, he verified his and the vaccinees' immunity by grafting human smallpox.
In 1806 Sacco reported that he had personally had more than 130,000 people vaccinated or inoculated in the Departments of the Mincio, Adige, Lower Po and Panaro Rivers alone. In short, those vaccinated in the Kingdom of Italy reached 1.5 million, drastically reducing smallpox mortality. The vaccine soon spread to the Kingdom of the Two Sicilies as well. After the unification of Italy, smallpox vaccination was made mandatory for all newborns starting in 1888.
Variola major's successor: monkeypox
Following the eradication of the virus, we saw an increase in the spread of one of the other viruses in the Orthopoxvirus genus, Monkeypox virus responsible for monkeypox, which is now the most prevalent form of smallpox in the world.
First identified in 1970 in the Democratic Republic of the Congo, it is now present in 11 countries in West and Central Africa: Benin, Cameroon, Central African Republic, Democratic Republic of the Congo, Gabon, Côte d'Ivoire, Liberia, Nigeria (where the largest outbreak is ongoing, with more than 700 cases as of 2017), Republic of the Congo, Sierra Leone , and South Sudan. Outbreaks typically tend to be concentrated near tropical rainforests, although in recent years we are seeing more cases in urban areas.
The clinical picture of the disease is similar to that of classical smallpox, although much less severe (the mortality rate has historically hovered around 10 percent, although today it is more often between 3 and 6 percent). With an incubation period of 7 to 14 days, though it can also range from 5 to 21, symptoms occur in an initial period lasting up to 5 days, characterized by fever, headache, muscle aches, back pain, and swollen lymph nodes. The second phase begins 1-3 days after the onset of the disease and manifests with a rash that typically focuses on the face and limbs.
As with the other forms of the disease, monkeypox is not curable, but tends to resolve spontaneously in 2-4 weeks. However, we do know that the vaccine for classical smallpox is 85 percent effective against this form of the disease and can be used in emergency situations to limit its spread, as is happening these days in the United Kingdom.