Ho Chi Minh City recorded 10,052 dengue fever cases in January-May, up 46.4 percent year on year, according to the local Center for Disease Control (HCDC).
The number of serious cases in the first five months was 194, a fivefold jump compared to the same period of last year, the HCDC added.
Seven dengue fever fatalities have been documented in the metropolis since the beginning of this year.
From May 20 to 26, Ho Chi Minh City logged 1,402 dengue fever cases, up 48.4 percent compared to the average of the previous four weeks.
Rising cases were recorded in Thu Duc City and all districts except for District 12 and Phu Nhuan District.
During this period, about 121 new outbreaks were detected in 71 wards and communes in 15 districts and Thu Duc City.
Dengue fever is an infectious disease that is transmitted by the bite of an Aedes mosquito infected with a dengue virus, according to the World Health Organization.
Symptoms include fever, headaches, muscle and joint pains, and a characteristic skin rash that is similar to measles.
The number of patients with hand, foot, and mouth disease has also spiked across the city, according to the HCDC.
From May 20 to 26, the metropolis reported 1,070 cases, up 81.7 percent compared to the average of the previous four weeks.