Lab tests have confirmed that a virulent strain of hand, foot and mouth disease known as EV-71 is to blame for many of the 59 cases reviewed, including 52 deaths, according to a joint statement from the World Health Organization and Cambodian Health Ministry. The numbers were lowered from the initial report of 62 cases.
EV-71 is a virus that can result in paralysis, brain swelling and death. Most of the Cambodian cases involved children under 3 who experienced fever, respiratory problems that quickly progressed and sometimes neurological symptoms.
Hand, foot and mouth disease has been raging across Asia, and usually causes a telltale rash. WHO spokeswoman Aphaluck Bhatiasevi said rashes were seen in only a few of the Cambodian cases, and it's possible that steroids administered by doctors could have masked the symptom.
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, Bhatiasevi said.
Hand, foot and mouth disease is spread by sneezing, coughing and contact with fluid from blisters or infected feces. It is caused by a group of 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.
The virus gets its name from the symptoms it causes, including rash, mouth sores and blisters covering the hands and feet. Many infected children are not sickened at all, but remain capable of spreading 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 in Vietnam 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.