Tran Thanh Duong, director of the National Institute of Malariology, Parasitology and Entomology, released the warning on May 14 following a high incidence of dengue fever over the past few months. 
 

The virus, which often readily spreads during June in the south and September in the north, has recently emerged year-round due to weather and environmental changes.

Notably, the number of infections is increasing considerably in big cities. Since the beginning of 2014, Ho Chi Minh City alone has recorded 2,600 cases, up 28% compared to a year earlier.

Experts said that they have found four variants of the dengue virus (D1, D2, D3, D4) and that the disease will continue to get more complicated during the summer months.

Prevention medicine centres in provinces and cities have been asked to implement urgent measures to contain the spread of the disease.