The Vietnamese Ministry of Health dismissed the idea that a transmissible skin disease was responsible for the 21 deaths and over 200 cases that have occurred in Vietnam's central Quang Ngai province since April 2011, reported Vietnam News Agency on Tuesday.

The report quoted Deputy Minister of Health Nguyen Thanh Long as saying that so far no sign of infection was found, which means the condition is not caused by a virus or bacteria. There is no proof of that the disease is spread through the air, via a water source or between humans.

Long made the statement at a press briefing in Hanoi on Monday after the ministry completed a fact-finding mission to the province's Ba To District, some 730 km south of capital Hanoi.

Long also confirmed that the ministry still had not identified the cause of the disease, called Inflammatory Palhoplantar Hyperkeratosis Syndrome, which is characterized by thickened skin over the palms of the hands and soles of the feet. A majority of the patients also developed liver problems.

Most of patients died because of multi-viscera failure, liver poisoning and immune deficiency, Long added.

The deputy ministry said that more than 1,900 diseased samples had been collected for testing at all laboratories nationwide with the support of international experts from the World Health Organization (WHO), the United States' Center for Disease Control and Prevention (CDC) and Japan.

The ministry also confirmed that they would collaborate closely with WHO, CDC and other international organizations to find the cause in the near future.