An outbreak of a mystery illness dubbed "Disease X" has killed dozens in the Democratic Republic of Congo (DRC), health officials say.

Up to 143 people have died from the infectious disease, the country’s deputy provincial governor, Rémy Saki, told the Associated Press on Tuesday.

The deaths occurred in the Panzi health zone of Kwango province between Nov. 10 and Nov. 25, AP reported this week.

DEADLY OUTBREAK OF MARBURG, OR ‘BLEEDING EYE VIRUS,’ LEADS TO TRAVEL ADVISORY

Primary symptoms include fever, headache, cough and difficulty breathing.

Most of those affected are children younger than 5 years old.

An outbreak of a mysterious illness dubbed "Disease X" has killed dozens in the Democratic Republic of Congo (DRC), health officials say. (iStock)

The World Health Organization (WHO) confirmed to Fox News Digital that as of Dec. 4, the Panzi health zone has recorded 394 cases and 30 deaths from the so far undiagnosed illness.  

"In addition to the 30 deaths recorded in health facilities, 44 other deaths were reported from the community, but these have not been investigated yet," WHO added.

BIRD FLU SURGES IN SEVERAL US STATES WITH REPORTS OF NEW OUTBREAKS: 'GETTING WORSE'

The cases began in mid-October and the Ministry of Health was notified on Nov 29.

"Among the cases reported as of Dec. 3, 63% are children under the age of 15, who also account for 81% of the reported deaths," WHO told Fox News Digital.  

"Among these, young children under the age of 5 years are particularly affected."

Doctors take samples from a patient at the mpox treatment center in the Democratic Republic of Congo, on Aug. 16, 2024.  (Getty Images)

The DRC’s provincial health minister, Apollinaire Yumba, urged residents to be cautious and to avoid contact with dead bodies to prevent infection, AP reported. The country is also requesting medical supplies.

"Investigations are ongoing and WHO is sending people and supplies to support the authorities," WHO told Fox News Digital via email.

Given that the area is "rural and remote," access can be a challenge, especially given the ongoing rains and high conflict rates, the organization added. 

"There is a lack of medicines and medical supplies, since the disease is not yet known."

"A national rapid response team is on the ground to collect samples for laboratory testing and better understand the epidemiological situation," WHO stated.

"We will have initial lab test results within the next few days from labs in the nearby city of Kikwit."

CLICK HERE TO GET THE FOX NEWS APP     

Jean Kaseya, director of the Africa Centres for Disease Control and Prevention, spoke at a press conference on Thursday.

"We have a delay of almost five to six weeks, and in five to six weeks, so many things can happen," Kaseya said. 

"Ongoing testing will help us to understand what is the issue."

Up to 143 people have died from the infectious disease, the country’s deputy provincial governor, Rémy Saki, told the Associated Press on Tuesday. (iStock)

Lucien Lufutu, president of the civil society consultation framework of Kwango province, who is in Panzi, told the AP that the local hospital is not equipped to treat the influx of ill patients.

"There is a lack of medicines and medical supplies, since the disease is not yet known, most of the population is treated by traditional practitioners," he said.

CLICK HERE TO SIGN UP FOR OUR HEALTH NEWSLETTER

When contacted by Fox News Digital, the U.S. Centers for Disease Control and Prevention (CDC) said it is aware of reports of an illness in southwest DRC.  

"U.S. government staff, including those from U.S. CDC’s country office in Kinshasa, are in contact with DRC’s Ministry of Health and stand ready to provide additional support if needed," a spokesperson said.

Doctors weigh in

Dr. Marc Siegel, clinical professor of medicine at NYU Langone Health and Fox News Senior Medical Analyst, cautions against calling this new outbreak "Disease X."

"I am not sure that I would call the current outbreak of a mysterious killer virus in DRC ‘Disease X,’ because it is too soon, still few cases, and we know too little about it," he told Fox News Digital.

A social mobilizer washes his hands as he gets ready to receive members of the community ahead of the launch of the mpox vaccination campaign at the General Hospital of Goma on Oct. 5, 2024.

"Disease X is a term coined by the WHO in 2018, which refers to an unknown pathogen that is a priority because of its potential to cause a pandemic," Siegel went on. "It is generally seen as a hypothetical, or ‘placeholder’ term, which is why it may not be appropriate here."

The doctor noted that this unknown pathogen appears to be respiratory because it causes respiratory symptoms, along with fever, headache, cough and "a high risk of death."

"We need to know a lot more about it before we can assess the risk, including the risk of spread," Siegel added.

The first cases of Disease X were reported on Oct. 24, but health authorities were not notified until Dec. 1, according to reports. (iStock)

Sam Scarpino, PhD, director of AI and life sciences at Northeastern University in Boston, noted that anytime there’s a large reported cluster of cases and/or deaths related to a respiratory infection, "we should be concerned."

"The level of concern goes up if there’s no clear pathogen identified," he told Fox News Digital. 

"We will have initial lab test results within the next few days from labs in the nearby city of Kikwit."

"Moreover, there have been anecdotal reports of people dying from respiratory distress," Scarpino went on. "Many different infections can produce respiratory symptoms, but individuals potentially dying from these symptoms is worrying."

There is the possibility, however, that the pathogen could turn out to be something that is "not high-risk from a pandemic perspective," he noted. 

"A national rapid response team is on the ground to collect samples for laboratory testing and better understand the epidemiological situation," WHO stated. (iStock)

"What’s needed right now are resources to perform genomic characterization of the pathogen and ensure that individuals currently impacted have adequate medical care," Scarpino said.

"We also want to ensure that health care workers and other first responders have access to protective equipment, sanitation and other resources to keep them safe."

For more Health articles, visit www.foxnews.com/health

The Congo is already grappling with an ongoing outbreak of mpox, a viral disease caused by an orthopoxvirus. A global emergency was declared in August.

In recent weeks, health officials have reported between 200 and 300 confirmed mpox cases weekly, according to data from the World Health Organization (WHO).