By Priyadarshini Chatterjee, University of Oxford, UK
We have all had multiple viral infections in our lifetime, be it the flu or a more serious disease such as measles. Every year, new strains of virus feature in the spotlight, making it a challenge to keep up with treatment options. But when did we first come across viruses? How did we differentiate them from other disease-causing pathogens? How did the first vaccinations against viruses come about?
Figure 1: Viruses stained with a green dye [goodfreephotos.com].
The earliest depiction of a viral infection was found on an Egyptian stele from the 18th dynasty (1580-1350BC). It shows a priest with a foot drop deformity which is a symptom of polio. Paralysed, polio infected Egyptian mummies have also been found, while others such as Ramesses V show evidence of smallpox. The Hittites, who lived in the Middle East, described smallpox on clay tablets and accused the Egyptians of infecting them during the Battle of Kadesh. There were major epidemics of what scholars suspect to be measles or smallpox in both Greece and Rome in 430BC and 165AD respectively, and as the smallpox virus spread like wildfire across Europe, Africa and Asia, some cultures started to worship deities dedicated to smallpox.
A similar virus is the rubeola virus that cause measles. This virus dates to the 7th century but it was not until the 10th century that the Persian physician Zakariya al-Razi identified it and documented its clinical symptoms, differentiating it from smallpox. The occurrence of measles was so common in children at one point, that it was considered to be a normal stage of human development.
The Middle Ages and The Renaissance
In the middle ages, the population of Europe was growing at a rapid rate. Cities and towns were extremely filthy with open drains and no proper sewer systems, and it was widely believed that sins or bad smells caused infections. There were various odd treatments for viral infections including ointments from cats that had been roasted in hedgehog fat. In addition to the growing population, the Crusades aided the spread of viruses during the 5th and 7th centuries.
Shortly after Henry VII’s victory at the Battle of Bosworth in 1485, there was a breakout of influenza, then known as “the English sweat”. It is believed that the virus was brought to England by French mercenaries who had come to fight alongside the Tudor army. Unlike the other viruses people knew about, this virus did not offer immunity after the first attack. Surprisingly, this disease was prevalent among the English nobility, amongst which, Anne Boleyn and Cardinal Wolsey are said to have contracted the disease.
Figure 2: Lady Mary Wortley Montagu.
Lady Mary Wortley Montagu is widely credited as the first person to introduce the inoculation of smallpox in Europe. Lady Montagu was an aristocrat whose husband was appointed British Ambassador in Istanbul where “variolation” was a widespread practice. Variolation involved injecting the pus from smallpox afflicted individuals into unaffected individuals, giving them protection from the disease. However, at the time, no one knew why this worked as nothing was known about the immune system or its response to viruses. As Lady Montagu had the disease herself and had lost her younger brother to it, she ordered the embassy doctor to variolate her son.
When, due to political changes, she returned to London in 1718 she also variolated her daughter. She later persuaded the Prince and Princess of Wales to sponsor a public demonstration of the procedure. Six prisoners were offered a full pardon on the condition that they partake in this public demonstration. They were variolated and all six of them recovered quickly from the procedure. This proved that it was effective and safe causing the British royal family to be inoculated. Later, the practice was proved to be not entirely safe as there was a one in fifty chance of death. In addition to this, it was expensive. Medical practitioners charged exorbitant rates and would sell the method to other practitioners, making it a lucrative business.
Figure 3: Edward Jenner administering the smallpox vaccine.
Edward Jenner developed the world’s first vaccine. Jenner knew of the local belief that milkmaids who contracted a disease called cowpox were immune to smallpox and being a scientist at heart, he decided to test the theory. In 1796, he injected a young boy with the pus of a milkmaid infected with cowpox. Several days later, he exposed the boy to smallpox, but the boy never contracted it -he was immune to smallpox. This method was safer than variolating as cowpox was a mild disease. Jenner coined the term vaccination to describe the process, as “vacca” means cow in Latin.
By 1840, vaccination was a widespread practice and free vaccinations were introduced for the poor. By 1853, vaccinations were made compulsory and parents were fined or imprisoned if their children were not vaccinated – the public did not take this news well. They formed as Anti-Compulsory Vaccination League and riots broke out in several towns. The ACVL said that the government was encroaching on their “personal liberty”. Despite a new outbreak of smallpox in Gloucester, a new Vaccination Act was passed in 1898 with a “conscientious objector” clause, that is, parents who did not believe in vaccinations would be granted exemptions.
It was only at the end of the 19th century that a scientific approach was taken to examine the cause of these diseases. Despite the development and introduction of vaccinations, the cause of disease and the existence of viruses was still unknown. In 1884, the Chamberland-Pasteur filter was invented. Its pores were smaller than the size of a bacteria and could be used to remove bacteria from a liquid. Dmitri Ivanoski used this device on a virus infected plant. However, the liquid remained infectious post filtration, therefore, the causative agent was not bacterial. Martinus Beijerinck, a Dutch microbiologist, concluded that it was “contagious living liquid” and introduced the term “virus”, which is Latin for slimy fluid. Wendell Meredith Stanley, using protein methods and crystallisation, proved that the infectious component was particulate in nature.
An entirely new branch of science was set up: virology. Since then, a huge variety of viruses have been found, vaccines introduced, anti-viral drugs discovered and have been manipulated for gene therapy. Unfortunately, despite the huge progress in the field of virology, due to their rapid mutation rate, viruses continue to pose a threat.
I am a second year undergraduate student studying Biochemistry at the University of Oxford. In my free time I enjoy playing the piano, reading and drawing.