Utility of fungal polymerase chain reaction on nasal swab samples in the diagnosis and monitoring of sinonasal aspergillosis in dogs

Abstract

Background: In dogs with sinonasal aspergillosis (SNA) the utility of PCR in the diagnosis and monitoring of the disease after treatment has not been assessed.

Objectives: To evaluate the presence of fungal DNA using quantitative PCR targeting Aspergillus fumigatus (Aspfum) and Aspergillus spp. (PanAsp), and PCR targeting multiple fungal species (PanFun), in samples obtained from nasal cavities of dogs with SNA, other nasal diseases and healthy dogs.

Animals: Sixty-two dogs including 20 with SNA, 12 with cured SNA (of which 10 are from the SNA group), 20 dogs with Non-SNA nasal disease, and 20 healthy dogs.

Methods: Prospective cross-sectional study. Aspfum, PanAsp, and PanFun were performed on blindly collected nasal swabs obtained in anesthetized dogs.

Results: In SNA dogs, Aspfum and PanAsp were positive in 13/20 and 14/20 dogs. In all dogs in the 3 other groups, A. fumigatus DNA was not detected using Aspfum. PanAsp was positive in 3 non-SNA dogs: 1 with cured SNA and 2 with Non-SNA nasal disease. A Ct cut-off value of 33.3 for Aspfum demonstrated 65% sensitivity and 100% specificity. A Ct cut-off value of 34.5 for PanAsp demonstrated 70% sensitivity and 96.2% specificity. PanFun was positive in 16/20, 12/12, 19/20, and 7/20 dogs in the SNA, cured SNA, Non-SNA, and healthy groups, respectively.

Conclusion and clinical importance: Aspfum and PanAsp on blindly collected nasal swabs can be useful for the detection of SNA at diagnosis and at cure, especially when more invasive methods are not available.

Keywords: PCR; aspergillosis; diagnosis; dogs; nasal swabs.