BEIJING -- Beijing municipal health authorities said Monday that a four-year-old boy, who was tested positive for H7N9 flu virus, was determined to be a H7N9 flu virus carrier.

The boy, surnamed Zhu, was tested positive for H7N9 flu virus by the Beijing Center for Disease Control and Prevention Sunday evening.

Zhu has so far shown no flu symptoms and is receiving medical observation in Beijing Ditan Hospital.

Local health officials said a neighbor of the boy had bought chicken from the family whose seven-year-old girl became Beijing's first H7N9 case.

The carrier was discovered after local disease control authorities tested 24 people who raise poultry in a village of Cuigezhuang township, Chaoyang District.

Chinese health authorities said on Sunday the new form of flu is spreading but no evidence showed it can be transmitted through human-to-human contact.