The way Monkeypox is transmitted may have changed and scientists don't know why.

Before the most recent outbreak, Monkeypox was usually only recorded in areas of Western and Central Africa. In recent weeks, however, more than 1,000 cases have been recorded across 29 countries.

Before now, direct, physical contact was believed to be the main source of transmission, with a few exceptions—there have been examples where the virus may have been spread through airborne particles.

Brittany L. Kmush, an associate professor at the Department of Public Health at Syracuse University, told Newsweek that although "typically, monkeypox is not thought of as an airborne virus," its mode of transmission may have changed and subsequently, caused this outbreak.

A file image shows the monkeypox virus. Scientists believe it has changed the way it spreads. wildpixel/Getty

"It is much easier to catch monkey pox from direct contact with the rash than through airborne exposure. However, the current monkeypox outbreak seems to be somewhat different from past outbreaks," she said.

"It is less likely that patients have symptoms of general illness prior to the rash appearing and the rash is generally less severe. There is also more community transmission than in the past, that is, cases where the source of infection isn't known. Therefore, it is possible that the mode of transmission in this instance is also somewhat different. It is important to remain up to date and follow the guidance given by public health officials as this outbreak continues to unfold."

Monkeypox mutations?

Given the unusual nature of the outbreak, scientists initially suspected that the virus may have mutated into a more transmissible form. However, genomic sequences studied from the outbreak don't back this up, WIRED reported.

It was suggested that stopping the smallpox vaccination program led to a decline in immunity against orthopoxviruses like monkeypox. Increasing air travel post COVID could also helps virus spread. But this does not explain why the outbreak is happening now, Jo Walker, from the Yale School of Public Health, told the magazine.

"Maybe a random series of mutations in the last few months set this all off," he said. "Or maybe our luck ran out, and it took until now for a monkeypox case to make its way to a major population center, get on an airplane, and kickstart an outbreak without hitting a dead end."

There is also the question as to whether the virus can be sexually transmitted. Some, but not all, cases have also been linked to sex. Scientists are still researching this.

According to Reuters, researchers at Italy's Spallanzani Institute have detected fragments of the monkeypox virus in semen from six of seven samples from monkeypox patients. One of these was found to be potentially capable of infecting another person. These results are extremely preliminary and should be taken with caution, however.

Can Masks Curb the Spread?

There has been debate on how airborne the virus is— and subsequently, whether wearing masks could help curb the spread.

There have been no examples of airborne transmission in the current outbreak that experts know of, however it has occurred in the past.

Experts previously told Newsweek that cases where monkeypox appears to have spread through airborne particles may have been caused by blister fluids suspended in the air.

The CDC previously posted guidance advising travelers to wear a mask to help curb the spread—however that was then taken down. The CDC said in a statement it had removed the advice as it "caused confusion."

However, this sparked a backlash across social media. Scientists have accused the CDC of making things more confusing. Epidemiologist and health economist Eric Feigl-Ding tweeted about this, pointing to the U.K. government, which has listed monkeypox as an airborne virus of "high consequence."

Even if monkeypox can be airborne, experts say it remains very different to COVID.

"Masks can prevent the spread of monkey pox. Monkeypox can be spread through respiratory droplets, but typically only in cases of prolonged face to face exposure. This might occur among health care workers caring for infected patients or among household members," Kmush tweeted.

"If you are a healthcare worker treating monkeypox cases or someone in your household is a monkeypox case, then wearing a mask in addition to other infection prevention measures will help prevent the spread of monkeypox. However, for the general public, wearing a mask is much more effective against more common viruses such as COVID or the flu."

This article has been updated to include additional context.

File images show London and a test tube of the monkeypox virus. The U.K. currently lists the virus as airborne.