Aspergillus felis: New Fungus Found in Australia, Causes Infections in Humans, Cats

Jun 18, 2013 by Sci-News.com

A multinational team of biologists writing in the open-access journal PLoS ONE has identified a new species of fungus that causes life-threatening infections in humans, dogs and cats.

Aspergillus felis (Barrs VR et al)

Aspergillus felis (Barrs VR et al)

Study lead author Dr Vanessa Barrs from the University of Sydney said: “this all originated from spotting an unusual fungal infection in three cats I was seeing at the University’s cat treatment centre in 2006.”

“These cats presented with a tumor-like growth in one of their eye sockets, that had spread there from the nasal cavity. The fungal spores are inhaled and in susceptible cats they establish a life-threatening infection that is very difficult to treat.

Finally I was able to confirm this as a completely new species, Aspergillus felis, which can cause virulent disease in humans and cats by infecting their respiratory tract. We were able to demonstrate that this was a new species of fungus on a molecular and reproductive level and in terms of its form.”

Aspergillus felis (Barrs VR et al)

Aspergillus felis (Barrs VR et al)

Dr Barrs said that similar to the closely related fungus Aspergillus fumigates, “this new species of fungus can reproduce both asexually and sexually – and we discovered both phases of the fungus.”

Since the first sighting of Aspergillus felis, more than 20 sick domestic cats from around Australia and one cat from the United Kingdom have been diagnosed with the fungus.

The fungus appears to infect otherwise healthy cats but in the two humans identified it attacked an already highly compromised immune system.

The disease is not passed between humans and cats but its study in cats will not only help their treatment but provide a good model for the study of the disease in people. There is only a 15 percent survival rate of cats with the disease and it has so far proved fatal in humans.

To date only one case has been identified in a dog.

Aspergillus felis colonies growing seven days at 25 Celsius degrees on Czapek Yeast Extract Agar, left, and Malt Extract Agar, right (Barrs VR et al)

Aspergillus felis colonies growing seven days at 25 Celsius degrees on Czapek Yeast Extract Agar, left, and Malt Extract Agar, right (Barrs VR et al)

“We are right at the start of recognizing the diseases caused by this fungus in animals and humans. The number of cases may be increasing in frequency or it may just be we are getting better at recognizing them.”

“Fungi like Aspergillus felis can be easily misidentified as the closely related fungus Aspergillus fumigatus, which is a well-studied cause of disease in humans. However, Aspergillus felis is intrinsically more resistant to antifungal drugs than Aspergillus fumigatus and this has important implications for therapy and prognosis,” Dr Barrs concluded.

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Bibliographic information: Barrs VR et al. 2013. Aspergillus felis sp. nov., an Emerging Agent of Invasive Aspergillosis in Humans, Cats, and Dogs. PLoS ONE 8 (6): e64871; doi: 10.1371/journal.pone.0064871