Health experts are warning once again that the world may be facing another big pandemic and could be caused by viruses that are related to smallpox, a disease that once thought to be eradicated forever.
Smallpox, or medically termed Variola, was finally eradicated in 1980 after a massive vaccination campaign against the devastating infectious disease launched by the World Health Organisation (WHO) all over the world.
Its elimination was one of the greatest achievements in the history of public health.
While the virus is no longer able to spread naturally, it has not disappeared completely. Carefully secured samples are still held in a limited number of high security laboratories, so accidental/natural outbreaks are very unlikely.
However, the success of eradication has had an unintended consequence according to scientists. Smallpox vaccinations were stopped decades ago, and thus a certain level of immunity in the population was gradually on the decline.
This lowered protection does not only apply to the smallpox itself but related viruses from the same family as well.
Smallpox is part of the group of viruses commonly known as the orthopoxviruses, that includes other viruses that can infect humans, such as monkeypox, and still less well-known viruses like buffalo pox, camel pox and boreal pox.
Experts say that as population immunity decreases, the possibility of these viruses spreading, mutating or evolving in a way that makes them more infectious to humans will increase.
History provides a fairly graphic warning about the danger. In the 20th century alone, smallpox is estimated to have killed around 500 million people around the world, making it one of the deadliest diseases that have ever been recorded.
Its ability to both spread and a high fatality rate led to horrific outbreaks across the continents.
Even though smallpox itself is still contained, the scientists warn that similar conditions can arise to enable a similar emergence of another orthopoxvirus into a serious global health threat.
This stresses the need for continued surveillance, research and preparedness especially in populations in which there is little or no existing immunity.
