A dangerous strain of the typically non-lethal hand-foot-and-mouth disease (HFMD) has killed 16 and infected more than 21,000 other people, mostly children, in Vietnam this year, according to the country's Ministry of Health.

HFMD typically causes fever, sores in the mouth and blisters on the hands and feet. However, the new EV71 strain can be fatal and is spreading among children under five, the World Health Organization said in a report.

Bhupinder Tomar, representative of the International Federation of Red Cross and Red Crescent Societies (IFRC) in Vietnam, told humanitarian news service IRIN: "Despite being a benign viral infection in developed countries, the strain EV71 of HFMD is causing multiple deaths of children under five here in Asia.

"We are especially worried about South Vietnam, where lots of children are in informal (hygienically unregulated) crèches while their parents work."

The HFMD disease spreads by direct contact with fluids from infected people. There is no vaccine for the EV71 strain yet.

EV71 appeared in Vietnam over the past year and has become a serious public health problem for children

The ministry has urged provincial governments to step up efforts to fight the disease, including strengthening hygiene in schools.

A total of 110,000 infections and 169 deaths related to EV71 were reported in 2011, mostly in the south of the country.

The disease is active year-round and peaks between April and May and then again between September and October.

In March 2012 there were twice as many deaths and seven times as many infections as in the same period last year.