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Monkeypox spreads from animals to humans and is considered endemic, or continuously present, in Central and West Africa.The Associated Press

As the number of confirmed monkeypox cases in Canada climbs and surveillance efforts widen, many in the pandemic-weary public are becoming increasingly concerned about the risks posed by this new outbreak.

One of the most urgent questions health professionals are trying to answer is why the decades-old virus is currently spreading outside of endemic areas in Africa.

“This is a different outbreak than we’ve ever seen before with monkeypox,” said Stephen Hoption Cann, clinical professor in the School of Population and Public Health at the University of British Columbia.

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Monkeypox spreads from animals to humans and is considered endemic, or continuously present, in Central and West Africa. But the current outbreak marks the first time monkeypox has spread from person to person in Canada. The virus is also spreading from person to person in a handful of other countries where it’s typically not found, including Belgium, France and Spain, which is why public-health experts are raising the alarm.

“What we’re seeing is something we’ve been worried about,” said Jason Kindrachuk, assistant professor in medical microbiology and infectious diseases at the University of Manitoba.

On Thursday, the Public Health Agency of Canada confirmed there are at least 26 cases of monkeypox in the country – 25 in Quebec and one in Toronto – with several others under investigation.

Monkeypox is related to variola, the virus that causes smallpox – a disease that caused a significant amount of death and suffering worldwide until it was officially eradicated in 1980, thanks to a global vaccination effort.

The long time since both the eradication of smallpox and the end of vaccination campaigns, however, means that many people have no immunity to that family of viruses. Those that were vaccinated before smallpox was eliminated have waning immunity. Those factors, combined with the rising incidence in recent years of monkeypox cases in Central and West Africa, are likely contributing to the current outbreak in countries such as Canada, Dr. Kindrachuk said.

Monkeypox is less severe than smallpox, and many cases resolve on their own. The West African strain of the virus has a fatality rate of 3.6 per cent, while the Congo Basin strain has a 10.6-per-cent fatality rate, according to the World Health Organization.

Monkeypox does not spread as easily as airborne viruses such as COVID-19. It’s typically transmitted through close contact with respiratory droplets, such as prolonged face-to-face contact; or through body fluids, such as from monkeypox sores or contaminated clothing.

The incubation period is typically one to two weeks, although the range is five to 21 days, according to the WHO. Now that monkeypox is being transmitted from person to person in Canada, officials say it’s important to understand the symptoms, which include fever, headache, exhaustion, muscle aches and swollen lymph nodes. A rash often appears within days of symptom onset, typically starting on the face and spreading from there.

Many of the cases have so far been identified in men who have sex with men, but monkeypox can spread easily in any population, Dr. Kindrachuk said. It’s possible the virus was introduced in those communities, but years of data suggest it can and will spread if conditions allow it.

Smallpox vaccines are highly effective against monkeypox, and officials in Quebec said they planned to start vaccinating close contacts of cases and other high-risk populations in the province as early as Friday. The vaccine can be administered after an individual is exposed to monkeypox in order to help prevent illness, which could be a major advantage in the effort to combat the current outbreak.

In addition to vaccines, there are some therapeutic treatments that can be used to treat people with monkeypox who become severely ill.

The incidence of monkeypox has been growing in Central and West Africa for years and experts say the current situation is a stark reminder of the need to invest in those regions.

“Unless we start doing something in Africa to prevent this growth of disease, we’re going to continue to see further outbreaks outside of Africa,” Dr. Hoption Cann said.

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