Canine sinonasal aspergillosis; a retrospective and prospective study

Abstract

The retrospective study reviews the success rates and disease free intervals (DFI) of the treatment options that treat sinonasal aspergillosis (SNA) used on the University of Utrecht. The success rates will be compared between the different treatment options and literature. The DFI will only be compared between the treatment options in Utrecht. Furthermore, the prospective study reviews the fungal and blood samples from dogs which were treated for SNA to find any significant factor what could explain why these dogs are infected. Material and method Retrospective study: treatment results were obtained from 78 different dogs with SNA obtained from the program ‘Vetware’ between March 2005 and April 2015. Some dogs underwent 4 treatments which could be different. The success rates and DFI were compared between the 4 treatment options in Utrecht and the success rates are also compared with literature. Prospective study: the histopathological and blood results from 6 dogs were compared with the reference ranges. Furthermore, the microbiologists from the biology department compared 27 dog, 29 human and 22 environmental fungal samples with each other and 3 reference strains (Aspergillus fumigates (AF 293) and type strains of A. fumigatus and A. neoelipticus). They performed DNA sequencing, resistance profiling and microscopical and cultural research on the fungus samples. Results Retrospective study: the cumulative success rates after 4 treatments of Utrecht were: 53.3% (option 1), 74.5% (option 2), 28.6% (option 3), 76.2% (option 4). Treatment option 4 was the reference group. Treatments option 3 was significant compared with treatment option 4. The success rates of treatment option 3 were significant lower than the success rates that were found in the literature. Furthermore, was it remarkable that the success rate of option 4 higher was than all the other options. The DFI were not significant when they were compared between the options in Utrecht, but was it remarkable that the DFI of option 4 was longer compare to the DFI of the other options. Prospective study: four dogs had a low albumin in their blood and the histopathological samples showed that the fungus did not infiltrate the mucosa. The cultures and DNA of the fungal samples from dogs showed lesser comparison with A. fumigatus then the human and environment samples. The DNA of the dog samples showed more comparison with A. neoelipticus. The dog samples were not resistant against the antifungal drugs: itraconazole, posaconazole and voroconazole, but these are not used in veterinary medicine. Conclusion Retrospective study: the success rates of Utrecht were all lower than the rates in the papers and option 3 was significant, but there are not many differences in treatment method. An explanation of the low success rates in Utrecht could be that due to the severity of disease. In Utrecht severe cases are referred, it might not be the case in the studies described in the literature. Additionally, the success rates of treatment option 3 were significant lower compared with treatment option 4. Prospective study: a low albumin concentration can ensure that dogs are more susceptible to SNA. But on the other hand it was remarkable that all 4 dogs showed some kind of blood loss in the weeks before the treatment and therefore could explain the hypoalbuminemia. The results from the microbiologists could confirm that A. neoelipticus (now assigned as A. fumigatus) is a different species, which might be the main fungus which cause SNA in dogs. Further research is needed to confirm this.