Over 8,000 cases of dengue fever with four dead have been recorded in Vietnam so far this year, according to statistics of Vietnam's health ministry on Wednesday.

The infected cases of dengue fever in the first four months of 2014 went down 38 percent over the same period in 2013, said the ministry. Up to 41 out of 63 localities in the country have been detected with dengue fever.

Tran Thanh Duong, head of the National Institute of Malariology, Parasitology and Entomology under Ministry of Health said at a meeting in Vietnam's capital Hanoi on Wednesday that the country records some 50,000 cases of dengue fever annually with 40 fatalities.

Four types of viruses (D1-D4) causing dengue fever are detected in Vietnam, making one person to be infected with dengue fever multiple times in one outbreak, the ministry warned.

The health official suggested raising people's awareness to avoid the disease as there has not been vaccine for dengue fever yet.