Mpox virus mutates to become more contagious in Africa, worrying some health experts

Public health officials are concerned about a new strain of monkeypox (formerly called “monkey pox”) that could spread more easily between humans. This infectious viral disease, related to smallpox, causes a distinct rash of lesions and bumps and can sometimes be fatal.

In late June, health officials raised the alarm about a strain of mpox spreading in the Democratic Republic of Congo. Specifically, the new strain is circulating in Congo’s North and South Kivu provinces. Scientists believe it mutated from a lineage called clade I that affected the United States and other Western countries between 2022 and 2023. “It is critical to address the recent surge in mpox cases in Africa,” Rosamund Lewis, the World Health Organization’s (WHO) technical lead on mpox, said in a press briefing.

Less than two weeks later, on July 11, the WHO reiterated that MPOS remained a global health threat, with 26 countries reporting cases to the agency as of July. This year, more than 11,000 cases have been reported and 445 deaths, with children most affected in the Democratic Republic of the Congo. South Africa also recently reported 20 cases of MPOS, including three deaths, the first cases reported in South Africa since 2022, according to the WHO. The WHO said all of the cases were in men, and most identified as men who have sex with men. No cases had been reported during international travel, suggesting community transmission is ongoing.

At a news conference, Dr Michael Ryan, executive director of the WHO’s Health Emergencies Programme, said it was concerning that public health officials did not have “a full understanding of the dynamics of community transmission right now in countries like Congo.”

“We’re always concerned about the potential for a disease to cross a border, whether it’s within Africa or across the world, and we saw how MPOX spread quite rapidly around the world in the previous event,” Ryan said, referring to 2022. “But what I would also say in terms of this previous event is how impressed I was with the way governments responded – but more importantly, the way affected communities responded.”

MPOX originated in wild animals in the jungles of West and Central Africa. It has occasionally been transmitted to humans. The first known human case of MPOX was detected in 1970 in a 9-year-old boy in a remote area of ​​Congo. According to the CDC, MPOX can cause symptoms such as a painful rash that can appear all over the body. Other symptoms are similar to the flu and include swollen lymph nodes, muscle aches, back pain, headache, fever, fatigue, and chills. Eventually, lesions form and progress through several stages before falling off.

“The lesions in my sensitive areas and my underwear area became really painful to the point where I couldn’t sleep,” Matt Ford, 30, told Self magazine in 2022. “I would describe the sensation as a dull, chronic ache that would turn into jolts of intense pain if I moved the wrong way; I’m not sure I’ve ever experienced anything like it.”

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MPOX is spread through direct contact with bodily fluids or wounds on the body of an infected person. It can also be spread through materials that have come into contact with bodily fluids or wounds that have been in contact with an infected person, such as clothing or bed linen. It can be spread through respiratory droplets when people have direct and close contact. Before the new strain, experts said this was not the main mode of transmission. According to WHO data, 91.4% of cases have been linked to sexual contact.

But the new strain now appears to spread more easily between humans, raising questions about how it is transmitted.

“It’s a phenomenon,” William Schaffner, a professor of infectious diseases at Vanderbilt University Medical Center, told Salon. “And the idea is that somehow, because of its rapid spread in Congo, the virus may have acquired a genetic component of increased transmissibility fairly recently.”

But the exact science behind the virus remains unclear, and more research needs to be done. Amesh Adalja, an infectious disease expert and senior scholar at the Johns Hopkins Center for Health Security, told Salon in a phone interview that the new strain appears to have additional mutations that make it more transmissible between humans.

“It appears that the clade I virus has evolved into another subform. We call it clade 1b, and this clade of the virus appears to have additional mutations that may allow it to spread more efficiently than other versions of mpox from person to person,” Adalja said. “And the problem is that this makes it harder to control because it spreads more easily and it appears that the severity of the disease is higher.”

However, Adalja stressed, in the broader picture, this does not affect the effectiveness of vaccines or antivirals. Indeed, there are vaccines against monkeypox. As Salon previously reported, in 2022, the United States released the Jynneos monkeypox vaccine from the Strategic National Stockpile, but supply was limited. Additionally, people who received the smallpox vaccine before it stopped being routinely administered in the 1970s will likely have protection against monkeypox.

There are still ways to test for it. In a press release, the CDC said that “viral sequencing from this group is thought to contain a deletion in a specific part of the genome that could impact the functioning of the CDC clade I PCR test.” However, they said that the FDA-approved CDC non-variola orthopoxvirus (NVO) PCR test and additional PCR tests that target other viral genes will still be able to detect the virus. Given that the mode of transmission is not airborne, Adalja said he is not that concerned about MPOX and does not think MPOX has “pandemic potential” in the United States.

“I don’t think a virus that spreads through contact can cause a pandemic,” he said. “Body contact, skin-to-skin contact, is compelling for any type of pathogen. When a virus can spread through the air, it’s hard to do anything, as we’ve seen with COVID-19.”

Both experts agreed, however, that the humanitarian crisis in Congo must be contained.

“From a humanitarian perspective, we are very concerned about the patients who are affected in Congo. Diagnostic resources are more limited there, especially in rural areas, and treatment is more limited,” Schaffner said, adding that the vaccine rollout has not been strong there. “One way to protect the rest of the world is to address the source more effectively, what we call source control. If we could control what is happening in Congo and neighboring countries, the risk of exporting this disease to many other countries around the world would be greatly reduced.”