Hac Thi Phuong Linh, 23, is being held at a police station in Tokyo for violating the quarantine law, her family said.

She was caught at Haneda International Airport on June 13 trying to bring in 10 kilograms of the pork rolls (nem chua) and 360 fetal duck eggs into Japan without declaring them.

Both items require quarantining before entry into Japan.

After testing, Japanese authorities revealed that the pork rolls contained the virus that causes the incurable African swine fever in all pig species.

It causes hemorrhagic fever with a 100 percent mortality rate. There is currently no cure for the disease though humans are not affected by it.

This is the first case of pork containing the virus caught in Japan.

Her husband told VnExpress that police came to their home last Sunday and arrested her. She is being held at a police station in Tokyo, he said. "Authorities summoned the family for questioning on Wednesday."

He and his wife have been married for just over a year and recently had a baby. His mother-in-law flew in with Linh to help take care of the child and so they wanted to bring some extra food to save money, he said.

According to Tokyo Broadcasting System Television, Linh told the police that the pork rolls were made by her mother for personal use, but the police suspected they were for selling to others.

During the interrogation, she admitted that she was planning to sell the rolls online.

After the African swine fever epidemic broke out in Vietnam last February, several countries, including Japan, imposed a ban on pork products from the country.

Passengers carrying raw or processed foods to Japan from Vietnam must have a certificate of safety, failing which they face three years' imprisonment or a fine of 1 million yen ($8,900).

Data from the World Organization for Animal Health showed that as of July 18 there were new or ongoing outbreaks of the disease in 14 countries and territories: Bulgaria, Hungary, Latvia, Moldova, Poland, Romania, Russia and Ukraine in Europe, Cambodia, China, North Korea, Laos, and Vietnam in Asia, and South Africa in Africa.