The Health Ministry Friday announced that a 2-year-old girl from Bac Kan Province was infected with the bird flu.
The girl from the northern province of Bac Kan is the seventh patient to be diagnosed with the flu, the Preventive Health and Environment Department said.
Vietnam has reported two H5N1-related deaths this year, a 38-year-old from the Mekong Delta Tien Giang Province in February and a 3-year-old in Ho Chi Minh City last month.
Bird flu infected five people in Vietnam last year, all of whom died.
Also on Friday, the Animal Health Department under the Ministry of Agriculture and Rural Development said the blue ear disease has recurred in the northern provinces of Thai Binh and Thai Nguyen.
A total of 1,090 pigs in Dong Hung District, Thai Binh and 21 in Phu Binh districts in Thai Nguyen Province, have been found with the disease.
In nearby Hai Duong Province, nearly 40 pigs have died of the disease, nine months after the government announced its successfully containment.
In June last year the department said that Vietnam has successfully curbed the spread of the foot-and-mouth disease, bird flu and the blue ear pig diseases.