Four days after two cats were confirmed to have been infected with avian influenza, commonly called bird flu, at an animal shelter in Seoul, three more suspected bird flu cases in cats were reported in the city on Saturday.

The three suspected cases of H5N1 virus infections were found at a cat shelter in Gwanak-gu, Seoul, the Ministry of Agriculture, Food and Rural Affairs said, adding that it will take two or three days to find out if the infections were highly pathogenic, resulting in severe morbidity and mortality.

Earlier last week, two cats at a shelter in Yongsan-gu, Seoul, were confirmed to have been infected with a highly pathogenic bird flu strain, marking the first infections of the virus in mammals in seven years in South Korea.

The shelter had reported a mysterious case of en masse cat deaths, with 38 of the cats under its care dead since late last month.

As the ministry immediately shared the situation with the Korea Disease Control and Prevention Agency, local governments and related agencies, the shelter has been disinfected and kept off limits.

The disease control agency and the local administration are looking into those who had contact with the cats and may have bird flu.

So far, no person who has been in contact with the cats has shown symptoms, the authorities said.

As in the confirmed cases in Yongsan-gu last week, those categorized as “high-risk,” who have been exposed to suspected cases of bird flu in cats, will be closely monitored for 10 days from the last day of contact.

Only one such person is currently being monitored and has not shown any symptoms yet.

Bird flu has spread throughout Europe in recent years, leading to a cull in May and June of millions of birds on French farms alone and affecting the supply of poultry meat and eggs, according to Reuters.

“There is a recent paradigm change in the ecology and epidemiology of avian influenza which has heightened global concern as the disease spread to new geographical regions and caused unusual wild bird die-offs, and an alarming rise in mammalian cases,” said Dr. Gregorio Torres, head of the Science Department at the World Organization for Animal Health.

In Poland last month, more than two dozen cats were infected with bird flu, although no people appeared to have gotten sick with the virus, according to the World Health Organization.

Four human cases of avian influenza A (H5N1) were also confirmed in Cambodia, China and Chile, the WHO said.