The country's top watchdog on products quality has urged local quarantine authorities to tighten inspections of birds and poultry from the United States after a shipment of carrier pigeons from there were found to be infected with psittacosis, or parrot fever.

Forty-one pigeons were seized at Beijing International Airport on June 21, after they were found to have not gone through proper quarantine procedures before being exported, the General Administration of Quality Supervision, Inspection and Quarantine said on Friday.

In addition, the Beijing quarantine authority also found the animal health certificates issued by the US stated that some of the pigeons were psittacosis positive.

The disease can be transmitted from infected birds to humans and cause symptoms similar to that of severe acute respiratory syndrome or SARS. The disease can be fatal.