The Bill and Melinda Gates Foundation of the US will donate US$400,000 to Vietnam to study new biological measures to control dengue, according to the Ministry of Health.

The four-year project is aimed at reducing the life spans of the mosquitos that transmit the disease to humans.

The ministry said in the first four month of 2006, there were 9,431 cases of dengue, 34.5 percent more than the same period last year, and six people died of the disease, twice as many as last year's figure.

Ninety-three percent of dengue-affected people live in southern provinces and cities.