Discovery of New Mould Linked to Disease in Pets and Humans

Six years of investigation by University of Sydney researcher, Professor Vanessa Barrs, has discovered a brand new species of mould, named Aspergillus felis that produces life-threatening infections within humans, cats and dogs and is particularly resistant to usual treatment.

Vanessa Barrs first noticed this fungal infection present in three cats she treated in 2006. Aspergillosis is the name given to infections caused by Aspergillus fungi, which reside in the soil. Their spores are disseminated in air currents. Humans can inhale several hundred spores on a daily basis, but they are efficiently eliminated by a healthy immune system. If inhaled by individuals with a weak immune system, they might overcome the body’s defences and begin growing inside the nose passage and sinuses.

The moulds may even spread towards the brain and other organs through blood ccording to Professor Barr. Although there exists more than 400 varieties of Aspergillus, fewer than 40 are actually documented to cause sickness in humans or animals. Aspergillus fumigatus accounts for most human cases of aspergillosis.

It may take the form of an allergic response, or the mould may possibly invade and destroy lung tissue. In domestic dogs and cats, this mould invades the nasal cavity and sinuses, causing fungal rhinosinusitis. Typically, it spreads its thread-like projections, referred to as hyphae, behind the eye and in to the brain.

Aspergillosis can be treated with modern anti-fungals. On the other hand species such as felis are resistant to these.

“Two people with known immunod-eficiencies are known to have died from infection with Aspergillus felis,” says Dr Vanessa Barrs, Associate Professor and researcher from the University’s Faculty of Veterinary Science. “Both cats and people are infected with the fungus from the environment. Cats don’t pass the fungus on to humans or vice versa; infection occurs when the spores are breathed in.”

Barrs’s study recently published within the journal PLOS One looked at various cats in Australia along with the UK, including purebreds as well as domestic crossbreeds. They seemed healthy, but on examination were found to suffer from rhinosinusitis as a result of Aspergillus felis. Many had a fungal ball growing behind an eye, which pushed the eyeball outwards.

Barrs and her colleagues are keeping an eye on this mould in order to combat it. “A. felis is intrinsically more resistant to antifungal drugs than A. fumigatus and this has important implications for therapy and prognosis,” Barrs said.

References

Barrs VR, van Doorn TM, Houbraken J, Kidd SE, Martin P, Pinheiro MD, et al. (2013) Aspergillus felis sp. nov., an Emerging Agent of Invasive Aspergillosis in Humans, Cats, and Dogs. PLoS ONE 8(6): e64871. https://doi.org/10.1371/journal.pone.0064871 [Accessed: 26 March, 2019].

Barrs, V., van Doorn, T., Houbraken, J., Kidd, S., Martin, P., Pinheiro, M., Richardson, M., Varga, J. and Samson, R. (2013). Aspergillus felis sp. nov., an Emerging Agent of Invasive Aspergillosis in Humans, Cats, and Dogs. [online] US National Library of Medicine National Institutes of Health Search. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683053/ [Accessed 26 Mar. 2019].

Talbot, J., Barrs, VR. (2013) One-health pathogens in the Aspergillus viridinutans complex  Medical Mycology, Volume 56, Issue 1, January 2018, Pages 1–12, https://academic.oup.com/mmy/article/56/1/1/3096174 [Accessed 26 Mar. 2019].

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