Australasian Science: Australia's authority on science since 1938

Cat-astrophic Fungus

By Stephen Luntz

Australian cats are falling ill from a newly identified fungus that features a very low survival rate.

Two people have died from the fungus as well, says A/Prof Vanessa Barrs of the University of Sydney, but these were people with severely compromised immune systems.

Barrs was alerted to the problem in 2006 when she noticed an unusual fungal infection in three cats brought to the University’s treatment centre. The fungus looks very similar to Aspergillus fumigatus, a common threat to people with severely compromised immune systems, but Barrs realised it was an entirely new species that she named Aspergillus felis.

The two Aspergillus fungi both grow on rotting vegetation and have an important role recycling nutrients. We breathe in large amounts of their spores every day, usually without harm.

However, A. felis is arousing concern because it is more resistant to antifungal drugs and also because many of the cats that have caught it did not appear to be otherwise unwell. Although numbers are still small, twice as many cats seem to be getting A. felis as A. fumigatus, despite the latter being far more common in humans.

“These cats presented with a tumour-like growth in one of their eye sockets, that had spread there from the nasal cavity,” says Barrs, who has published her results in PLoS One. While she is unsure why some cats are vulnerable, she notes that “40% of those who have got it were Persian or Himalayan breeds” and thinks their short noses make them particularly susceptible. Other feline victims may have had inherited genetic defects or pre-existing infections of the upper respiratory tract.

Survival rates for infected cats are just 15%.

A. felis is not spread from cat to human or human to cat. Cat lovers should look out for “chronic sneezing and nasal discharge, or swelling around the eyes,” says Barr, but these can be caused by many other things so veterinary assessment is required.