Mysterious deadly illness in Cambodian children tied to hand, foot and mouth disease

(CBS/AP) A mysterious deadly disease striking children in Cambodia may be a virulent strain of a common childhood illness called hand, foot and mouth disease.

Lab tests have confirmed that a virulent strain of hand, foot and mouth disease known as Enterovirus 71 (E-71) is to blame for some of the 59 cases reviewed since April, officials from the World Health Organization and Cambodian Ministry of Health said in a statement Sunday.

Unknown illness kills more than 60 Cambodian children, health officials say

Officials said of the 59 cases of children reviewed, 52 died. Previously officials said 61 out of 62children infected with the mystery ailment had died.

EV-71 is a virus associated with severe outbreaks of hand, foot and mouth disease that can cause paralysis, brain swelling and death. Most of the Cambodian cases involved children younger than 3 who experienced fever and respiratory problems that led to rapid shutdown and sometimes neurological symptoms. Children infected in the outbreak ranged from 3 months to 11 years old.

Epidemiologists are still trying to piece together information about the cases by interviewing parents because some details may have been omitted or missing from medical charts and specimens were not taken from most children before they died, said Dr. Nima Asgari, who is heading the WHO's investigation. Of 24 samples tested, 15 came back positive for EV-71.

"As far as I'm aware, EV-71 was not identified as a virus in Cambodia before," Asgari said, adding that based on the information now available it's likely that the majority of untested patients were infected with it.

"We are a bit more confident. We are hoping that we can come up with something a bit more conclusive in the next day or so," he said.

Hand, foot and mouth disease has been raging across Asia and usually causes a telltale rash. The disease is most common in children younger than 5, and younger kids tend to have worse symptoms. Within three to seven days, children may experience symptoms such as fever, poor appetite and sore throat that progresses to painful sores in the mouth. Typically located in the tongue, hums and inside the cheeks, the sores begin as small red spots that blister and often become ulcers. The rash usually is located on the hands and soles of the feet.

Blistering was only reported in some of the Cambodian cases, and it's possible that steroids administered by doctors could have masked the symptom or it may not have been recorded, Asgari said.

The lab results also identified other diseases in some cases, including mosquito-borne dengue fever and Streptococcus suis, a germ commonly seen in pigs that sometimes infects people, often causing meningitis and hearing loss.

Hand, foot and mouth disease is spread by sneezing, coughing and contact with fluid from blisters or infected feces. It is caused by enteroviruses in the same family as polio. No vaccine or specific treatment exists, but illness is typically mild and most children recover quickly without problems. Many infected children don't get sick but can spread it to others.

Neighboring Vietnam has been battling a surging number of hand, foot and mouth disease cases for the past few years, with EV-71 also wreaking havoc there. Last year, the disease sickened more than 110,000 people and killed 166, mostly children whose immune systems were not strong enough to fend off the infection.

China is also experiencing an outbreak, and more than 240 people have died of the disease there this year, according to China's Health Ministry.

The Cambodia investigation is continuing, but the H5N1 bird flu virus, SARS and Nipah - a deadly virus usually spread by fruit bats or pigs - have all been ruled out.

The CDC has more on hand, foot and mouth disease.