At least two countries outside Africa have reported cases of MPOX after the World Health Organization (WHO) declared earlier this week that the virus had become a “public health emergency.”

A relatively new variant of the virus, the so-called clade 1, has been spreading in African countries since 2022.

Earlier this year, it was reported that the Democratic Republic of Congo (DRC) experienced the largest outbreak of the disease ever recorded, with tens of thousands of people infected by June. The DRC government declared the disease an epidemic in December 2022.

Last week, the Africa CDC reported that Mpox has now been detected in at least 13 African countries. Compared to the same period last year, cases have increased by 160 percent and deaths by 19 percent, the agency said.

Here’s what we know so far about where the disease has spread, how it affects the human body, and how you can protect yourself from infection.

To which other countries has the new strain of Mpox virus spread?

Pakistan’s Health Ministry confirmed the first case of the virus on Friday and said the person was from Saudi Arabia.

Health officials said sequencing is currently underway to determine the exact strain of the virus the person was infected with.

On Thursday, Swedish health authorities reported the first Mpox case in the country and confirmed it was the clade 1 strain. They said the person became infected in Africa and was now being treated.

Clade 1 tends to cause a higher number of severe infections and appears to spread more easily through everyday close contact, including sexual contact.

On Friday, the European Center for Disease Prevention and Control (CDC) raised the risk alert level from “low” to “moderate” and urged countries to maintain a high level of vigilance for travelers from affected areas.

How does the virus attack the human body?

Mpox mainly affects humans and animals. It belongs to the same family of viruses as smallpox, but causes milder symptoms such as fever, chills and body aches. However, it can cause severe illness and in some cases even death.

The virus enters the human body through broken skin or the respiratory tract. It then spreads through the blood and causes flu-like symptoms and skin lesions.

According to Michael Marks of the London School of Hygiene and Tropical Medicine, scientists do not believe that Mpox has a direct effect on the immune system.

“Aside from the fact that all infections obviously cause transient immune system responses, we do not believe that Mpox has any long-term effects on the immune system,” he said.

Dr. Ngashi Ngongo, chief of staff of the Africa CDC, also told Al Jazeera that the virus only causes symptoms that last “two to four weeks.”

“It’s a disease. Either you get the severe form – then it leads to death – or you simply recover in two to four weeks. Everything goes back to normal,” he said.

How does the virus spread?

The virus is transmitted through close contact with an infected person or animal. In human-to-human infection, the virus can be transmitted through contact with skin lesions, skin-to-skin contact, and talking or breathing too close to an infected person.

Spread is also possible via contaminated objects such as surfaces, bedding, clothing and towels, as the virus enters the body through broken skin, the respiratory tract or the eyes, nose and mouth.

Marks told Al Jazeera that the main form of transmission is through skin contact, as the virus remains detectable on skin lesions for “about three weeks.” The virus is not transmitted through the respiratory tract, however, as “in most people the virus is gone from the throat after seven to 10 days.”

When transmitted from humans to animals, the virus typically enters the body through bites, scratches or contact with wounds from an infected animal.

What are the symptoms?

The disease causes flu-like symptoms and purulent lesions. It is usually mild but can be fatal.

Marks explained that the disease is “relatively mild” in most people and can include fever, muscle aches and a rash with “five to 25 lesions.”

“Some people feel significantly worse and may develop a more severe illness with hundreds of lesions all over their body,” he said.

What variables can cause more severe symptoms?

Marks explained that the disease causes only mild symptoms in most people, but some people are at higher risk of severe symptoms.

“For example, people with untreated HIV (a sexually transmitted disease) or weak immune systems are at even higher risk of severe disease. Children also appear to be at higher risk of severe disease,” he said.

Children, he explained, are likely to be more affected by Mpox than adults for “several reasons.”

“A lot of the transmission is in densely populated areas with lots of children, and children are probably more likely to run around and come into direct skin-to-skin contact with others – which then leads to transmission. Adults, on the other hand, have less direct contact with others,” he said.

Ngongo added that children are also at higher risk because their “defence mechanism” – the immune system – is still developing.

What treatment is available for this strain of Mpox?

There is currently no treatment for Mpox, but some antiviral drugs are being tested, Marks said.

“However, there is a vaccine that effectively reduces the risk. The priority must be to ensure adequate vaccine supplies to the most vulnerable populations in the Democratic Republic of Congo and surrounding countries,” he said.

“If we can vaccinate vulnerable people, they will be protected from infection and that will help bring the epidemic under control – so it will benefit both the vaccinated people and the population as a whole,” he added.

A vaccine against Mpox, which was used in many Western countries during the 2022 outbreak, is not accessible to poorer African countries, Ngongo said.

“There is no vaccine in Africa. What is left of that vaccine is being stockpiled in the West as part of its own emergency preparedness. But there is an ongoing emergency here,” he said.

Ngongo explained that through donations, Africa CDC has managed to procure 280,000 doses, but for the vaccine to be effective, people would need to take two doses, limiting the amount available to them to just 140,000 people.

How can you protect yourself?

Ngongo advised people to “revert to basic personal hygiene” and remember to wash their hands, avoid contact with sick people and advise people to go to hospital if they have symptoms so that the virus can be contained.

Mpox vaccines are also effective in protecting the population if you are in a country where they are available.

Could the Mpox virus spread further?

Given the ability of richer countries to stop the spread of the virus, scientists believe that transmission could be stopped relatively quickly if new outbreaks linked to Congo were identified quickly.

The “greatest risk,” says Marks, is in Central Africa, where the epidemic is occurring and spreading.

“It is likely that a few cases will spread to more distant areas, as in the Swedish case, but the greatest risk and focus of action must be on Central Africa,” he said.

Ngongo also urged people to learn from the COVID-19 pandemic and “act now.”