A man in Hong Kong has become the first person in the world to be infected with a rare strain of hepatitis E virus previously found only in rats and other animals, the South China Morning Post reports.

Chinese health officials say the infection is a wake-up call for Hong Kong to improve its public hygiene. The 56-year-old patient, who lives in public housing, underwent liver transplant surgery last year and tested positive for the virus after displaying recurring liver function problems following surgery.

While local authorities say there is no evidence of an imminent epidemic, the infection highlights Hong Kong’s growing public hygiene problem.

“These kinds of unusual infections, rare infections, first instances—even one case is enough to make public health authorities and researchers very alert about the implications,” said Siddharth Sridhar, a clinical researcher at Hong Kong University’s department of microbiology who was involved in studying the patient. Although it is still unclear how the man contracted the virus, it is thought he might have accidentally ingested rat droppings.

Doctors are reporting that the man’s condition is now “completely normal” after he was treated with ribavirin, a common antiviral medication.