Who mission to investigate 406 cases of unknown disease in Congo

The World Health Organization has sent a rapid response team to help investigate 406 cases of an unidentified disease labeled "Disease X" in Congo.

The World Health Organization (WHO) said in a statement Sunday that between Oct. 24 and Dec. 5, 406 cases of the unknown disease were reported in southwestern Congo, including 31 deaths, Xinhua reported. It's a flu-like illness with unspecified symptoms including fever, headache, cough, runny nose and aches and pains all over.

According to Italian daily Il Tempo, more than half of the cases are in children under the age of five, while a 50-year-old male tourist who was hospitalized in Lucca, Italy, appears to have recovered.

The WHO says the remote rural southwest of Congo, the continuous rainy season further impedes travel and limited health facilities make it a medical challenge for patients. Severe malnutrition was also present in all severe cases, complicating the identification of the source of infection.

The statement said malaria, which is common in the area, may be the cause of the cases, which the WHO is investigating.

But experts say there may be more than one cause.