Low testing rates in theDemocratic Republic of the Congo (DR Congo) are concerning the region's health experts as it battles an Mpox outbreak.

"In the DRC, only less than 40% of cases are tested, laboratory-confirmed," said Dimie Ogoina, an infectious diseae specialist at Niger Delta University, Nigeria.

DR Congo is "working blindly" as it tries to combat the outbreak, Ogoina said in a press statement.

There are now more than 3,500 confirmed Mpox cases across 11 West and Central African nations, with DRC accounting for 90% of cases.

Refugee camps in DR Congo are facing particularly severe Mpox outbreaks, with children most at risk.

But the Africa Centres for Disease Control and Prevention (Africa CDC) estimates the true number of cases could be more than five times greater.

"I believe cases in Africa are largely underreported because [with] the number of cases are occurring, the public health system cannot detect those cases," Ogoina said.

Experts warn the virus could spread further without better surveillance, control and treatment measures.

Mpox Clade 1b is a growing concern

Although DR Congo has the most reported cases, there are concerns Mpox will continue spreading beyond its borders.

Before now, the disease had never been reported in East African nations like Uganda, Rwanda, Burundi and Kenya.

That's changed since the recent outbreak. Each of these countries has reported cases of Clade 1b versions of the Mpox virus since April this year.

Clade 1 lineages are more virulent and deadlier  than the clade 2 lineages of Mpox which caused the global outbreak in 2022.
Evidence emergedat the start of this year that both Mpox clades are capable of sexual transmission

"We didn't know that Clade 1 can be easily transmitted through sexual contact. But now with the clade 1b, we see more sex workers affected and reporting of more sexual activities being, I can say, the main source of transmission or mode of transmission for this outbreak," said Placide Mbala-Kingebeni, an epidemiologist at the Institute of Biomedical Research in DR Congo, who led the study.

Mbala-Kingebeni said the virus is also adapting to become more difficult to detect. Genetic deletions — small changes in the virus’s genetic code — have made identifying the virus in tests more difficult.

"The reason that we are afraid about Clade 1b is because it seems very, very well adapted to human-to-human transmission," he said.

Vigilance required in efforts to curb Mpox spread

Though cases remain overwhelmingly confined to Africa,  single cases of Mpox Clade 1b have now been reported in Sweden  and Thailand.

Pakistan and the Philippines have each identified cases of Clade 2.

In a message posted to Twitter/X, Anne Rimoin, Chair of Infectious Diseases & Public Heath at University of California, Los Angeles (UCLA), US, said "an infection anywhere is potentially an infection everywhere."

Authorities in the European Union, UK and US still view risk to their populations as low overall, but the risk of cases being ‘imported' by overseas travelers has some experts flagging the need for vigilance.

Edited by: Fred Schwaller

Sources:

Kibungu, Emile M et al. “Clade I-Associated Mpox Cases Associated with Sexual Contact, the Democratic Republic of the Congo.” Emerging infectious diseases vol. 30,1 (2024): 172-176. doi:10.3201/eid3001.231164