This figure is 7.46 times higher than the same period last year, according to the Health Ministry's preventive medicine department.
Southern provinces account for the majority of patients, with 19 per 100,000 people infected, said Nguyen Van Binh, head of the department.
The virus is transmitted through saliva, blister fluid and faeces, but it is rare among adults, whose immune systems are generally strong enough to fight it off.
The disease is life-threatening in a small number of cases, owing to complications such as lung haemorrhages and meningitis.//DPA