The sudden appearance of smallpox in several countries has raised questions about how the virus has spread, which is more common in Central and West Africa.
Many health experts have said that cases of smallpox in 12 countries are not a cause for panic, as the virus is much less infectious than diseases such as Covid and is rarely fatal, but is very unusual.
First identified in 1970, cases of smallpox in monkeys only occur outside of Central and West Africa when a traveler becomes infected there and then returns home. These cases do not usually lead to wider outbreaks.
In other rare cases, owners of imported pets become infected, and animals such as rodents are believed to be sources of transmission.
But the World Health Organization [WHO] these cases are increasing in non-endemic countries, with no link to travel or animals identified in most of these cases.
So what are the main theories about why cases are suddenly emerging this time around?
Protection against smallpox vaccines is declining
Professor Raina MacIntyre, who heads the Kirby Institute’s biosecurity program, told the Medical Journal of Australia that “Decreased immunity to smallpox vaccination may be contributing to the increase in smallpox outbreaks. “.
“Mass vaccination stopped more than 40-50 years ago,” he said.
The smallpox vaccine offered the advantage of strong protection against smallpox. A study published in the journal PLOS Neglected Tropical Diseases in February that warned that cases of monkeypox were on the rise also attributed it to the cessation of widespread smallpox vaccination, as the virus has been declared by the WHO as eradicated.
Smallpox vaccination has never occurred in some countries where the virus has been detected, such as Australia.
In fact, cases have been on the rise for some time
Epidemiologists reported an increasing number of cases before the WHO issued its alert in early May. Better surveillance and global detection of cases of monkeypox were requested before the current outbreaks due to data suggesting a resurgence of the disease.
Between 2010 and 2019, cases re-emerged in Liberia and Sierra Leone after a four-decade absence and in the Central African Republic after three decades, found an investigation published in February and led by Pallas Health Research and Consultancy in the Netherlands.
Since the Covid-19 pandemic began, researchers and health workers around the world have also been more alert to the symptoms of viruses and more quickly report anything unusual, contributing to the detection of cases.
Could the virus have mutated?
Man-to-human spread is not easy for monkeypox; one study found that 3% of close contacts of someone with smallpox will become infected.
But the strange increase in cases has raised the possibility that the virus has mutated in a way that makes it more likely to be transmitted from person to person.
More data and lab analysis are needed to confirm this, but for now, it’s just a theory. Sequencing of the virus in laboratories is taking place, and we should know in a few days if the virus has changed.
Although smallpox has been around for decades, it is still considered a rare disease, meaning there is always more to learn about it.
The virus may have taken advantage of an ideal situation
When smallpox is spread among humans, it is through close physical contact with someone who has symptoms. The monkey’s smallpox can cause pus-filled lesions to develop on the skin, and contact with fluid from this rash, including contact with contaminated clothing and bedding, can spread the virus.
Sores in the mouth can also be infectious.
In the current outbreak, there have been groups between men who have sex with men, which was not the case before. But experts have warned against declaring it a sexually transmitted disease or attributing it to certain communities. It is much more likely that close contact that occurs during sex is responsible for the spread, rather than the sexual transmission of the disease.
Meanwhile, the WHO has urged people not to stigmatize people diagnosed with the virus.
“We have seen messages stigmatizing certain groups of people around this smallpox outbreak,” the WHO said in a statement.
“We want to make it very clear that this is not right. First of all, anyone who has close physical contact of any kind with someone who has monkeypox is at risk, regardless of who they are, what they do, who they decide to have sex with. or any other factor “.
The virus may not have mutated at all, but it may have taken an ideal opportunity to spread when all conditions were right; for example, in a community of people in close contact with each other, where there were multiple opportunities for dissemination.