The Hanoi-based Central Hospital for Tropical Diseases said Sunday they have admitted 18 patients that tested positive for cholera among 36 with acute diarrhea over the past week.
Most of the cholera patients are from the center of Hanoi, which has recorded no cholera cases over the past four months, according to the hospital.
Tests showed that most of them had eaten food that was not safe nor hygienic, namely dog meat and raw vegetables, before falling sick.
Le Anh Tuan, director of the Hanoi Department of Health, said shrimp paste, a dipping sauce used when eating dog meat, and the meat itself are not foods that normally cause the intestinal disease.
However, the way they are prepared could make someone contract cholera bacteria.
The current hot weather is ideal for the growth of the bacteria that causes the disease infecting hundreds of people in northern Vietnam in 2008 and 2009, he said.
Meanwhile, Nguyen Van Binh, deputy chief of the health ministry's Preventive Health Department, said the department has proposed that southern localities adjacent to Cambodia further promote preventive measures to local people, given that the disease has plagued many localities in the neighboring country.
Areas with shared water sources need to be checked and should be cordoned off if they are found to be contaminated with the bacteria, according to Binh.
He said the southern province of Binh Phuoc has recently admitted five people who contracted cholera in Cambodia.