Image copyright Getty Images Image caption The Omicron is a new version of the HIV virus
Canada has banned visitors from southern Africa after a mutated strain of the HIV virus isolated from a farmer in Zimbabwe sparked alarm.
The outbreak, which affects about 1,000 people in southern Africa, is already declared in a malaria-prone area.
The Canadian government said it had banned travel from the worst-affected countries, as well as Cuba and Haiti.
Travel in general from the southern African region is still banned.
The Omicron HIV virus does not spread from person to person, but can activate dormant cells in infected people’s blood.
The mutation is caused by a “cold-transport bug” which infects HIV – the virus which causes AIDS – by hitting it in the gut, in areas where they do not normally attack.
Image copyright Reuters Image caption This map shows the geographical area where the unusual strain has been detected
“They come into contact with blood vessels or vessels that are swollen and that can introduce changes into our blood,” Dr David Bennet of the National Public Health Laboratory in Waterloo, Ontario, told Canadian media.
Canada’s Public Health Agency said “the risk of the Omicron virus spreading to Canada from the South Africa-region is considered low”.
However, around 180 people have been affected in Zimbabwe and other countries.
Zimbabwe’s government has suspended imports of HIV drugs and developed an X-ray to detect it. It is understood there have been more than 60 X-ray cases.
The US Centers for Disease Control and Prevention warns that “if symptoms are severe enough, the infection could evolve into AIDS”.
Dr Bennet says the Omicron HIV strain could not spread outside southern Africa for “one to two years”.
“The likelihood of this occurring outside this region is very, very low,” he added.
Cuba, which is a relative haven for visitors to the region, has issued a public health notice saying the outbreak may affect its coast, but there have been no reported cases so far.
“All tourists, including travellers from southern Africa, can take the assurance that Cuba has taken the necessary steps to respond to any possible foreign involvement in its public health situation,” the health ministry statement said.
At least 62 people have been infected in South Africa and Zimbabwe, according to the Centers for Disease Control and Prevention.
The disease is easily transmitted in natural environments such as rivers and streams as the droplets from people’s coughs and sneezes can be picked up by animals.
However, small numbers of humans are infected every year.
The World Health Organization says there are usually about 16,500 people infected annually with HIV.
Professor Fritzi Vermogensen, a European director at the US global health research organisation the Atlanta-based Centers for Disease Control and Prevention (CDC), said the strong outbreak had not been detected for a long time.
“The infection from humans can only happen when a virus completely covers a microbe species,” she told BBC News.
Dr Bennet said Omicron HIV was not seen in people on the lookout for it.
“They [HIV-positive people] have antibodies, so to us they look healthy,” he said.
He added that scientists were looking at other ways in which the mutant virus could be transmitted.
Professor Jon Samuelsson, who heads the Global Alliance to Accelerate HIV/AIDS Research, said the issue highlighted the need for knowledge sharing.
“It’s very telling that most of the knowledge is happening in Africa and it has been decades since we really went down that path,” he told the BBC News website.
“Instead, there’s an arms race. We are working so well together now but we still have a lot of gaps.
“To me this is very damning. But if the [government] of the country we are concerned about can come forward with a solution,” he added.
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