Classification of Feline Aspergillosis
Similar to disease in humans, aspergillosis in cats can be classified by anatomic location, invasiveness, duration of infection, host immune status, pathology and pathogenesis. The most common site of disease is the respiratory tract, reflecting the primary inhalational route of infection.
Respiratory involvement is usually confined to the upper respiratory tract as chronic fungal rhinosinusitis (FRS). However, invasive pulmonary aspergillosis (IPA) can occur as a focal infection (Pakes et al. 1967; Hazell et al. 2011) or as part of disseminated invasive aspergillosis (DIA) (Fox et al. 1978; Ossent 1987; Burk et al. 1990). Focal invasive infections of the gut or urinary bladder have also been described (Stokes 1973; Adamama-Moraitou et al. 2001).Two forms of FRS occur in cats: sinonasal aspergillosis (SNA) and sino-orbital aspergillosis (SOA). Together, these conditions are referred to as feline upper respiratory tract aspergillosis (FURTA). SNA, which is usually non-invasive, is confined to the nasal cavity and paranasal sinuses. SOA is an invasive mycosis involving the sinonasal cavity, orbit and other paranasal tissues. It is the more common form of FRS, accounting for two-thirds of cases of FURTA (Wilkinson et al. 1982; Hamilton et al. 2000; Malik et al. 2004; Barachetti et al. 2009; Giordano et al. 2010; Halenda and Reed 1997; Kano et al. 2008, 2013, 2015; McLellan et al. 2006; Smith and Hoffman 2010; Barrs et al. 2007, 2012, 2013, 2014, 2015; Karnik et al. 2009; Quimby et al. 2010).
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