Originally posted at ProMED, this article described a new species of Aspergillus that is pathogenic to humans in a similar way to known species of Aspergillus that are pathogenic to humans - it is very rare for any infection to become established unless the human has a badly compromised immune system and is already vulnerable to all types of infection.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.Study lead author Dr Vanessa Barrs from the University of Sydney said: "this all originated from spotting an unusual fungal infection in 3 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."Dr Barrs said that similar to the closely related fungus _Aspergillus fumigatus_, "this new species of fungus can reproduce both asexually and sexually -- and we discovered both phases of the fungus."Since the 1st 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 2 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 also 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."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.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;http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0064871--Communicated by:ProMED-mail from HealthMap Alerts[This article indicates this is a new fungus, which does not transfer between humans and cats. The logical corollary is it does not transfer between cats and humans either, but that is not clearly stated. It may also be a discovery too new to completely understand the transfer of the fungus between organisms.