Four cases of avian flu, or bird flu, were confirmed among the endangered penguins at Boulders Penguin Colony in Cape Town, News24, a local news website reported on Saturday, citing a clinical veterinarian.

As of Friday, there had been four confirmed cases and another seven suspected cases, said Table Mountain National Park (TMNP) management.

Once seabirds show symptoms of bird flu, they usually die soon afterward, News24 reported, quoting Dr David Roberts, a clinical veterinarian at the Southern African Foundation for the Conservation of Coastal Birds (Sanccob) as saying.

The flu strain is the same as the one detected in seabirds in the Western Cape last year. That outbreak saw thousands of birds die in vulnerable colonies. Now, conservationists worry the same fate could await the endangered penguins, if no quick action is taken.

Roberts said that it could also pose a significant risk to breeding colonies if there is an outbreak in endangered species, like the African Penguin, Cape Cormorant and Cape Gannet.

The outbreak of bird flu last year killed an estimated 230 African penguins, said Roberts.

"At the peak of the outbreak, more than 500 affected birds were collected per day. The population-level effect was of an unprecedented scale, and approximately 15 percent of the South African population of Cape cormorants died from avian influenza in less than four months," he said.

The outbreak devastated the endangered Cape cormorant population in the Western Cape, resulting in the deaths of 24,000 birds. The worst-affected area was Dyer Island off Gansbaai, home to a Cape cormorant breeding colony.

According to Roberts, the actual number of deaths was likely to be far higher. Before the outbreak, there were an estimated 57,000 Cape cormorant breeding pairs in South Africa. However, the population had dropped by 50 percent over the last 30 years.

Bird flu refers to the disease caused by infection with avian (bird) influenza virus. Strains of the influenza virus primarily infect birds.