HONG KONG -- The Hong Kong Health Department says a second person in the city has been found to have contracted a strain of hepatitis that is carried by rats. Both human cases appear to be the first known globally.

The Health Department said in a statement Wednesday that it could not determine how the two people became infected with the particular strain of the hepatitis E virus.

Other strains of Hepatitis E are typically transmitted among humans through contaminated water, particularly in East and South Asia.

Both cases in Hong Kong were discovered long after the patients had been treated.

The latest case was found in blood samples from a 70-year-old woman with a compromised immune system who had been treated in May 2017.

The first case was reported in September.