Equine Pulmonary Aspergillosis with Encephalitic, Myocardial, and Renal Dissemination

Abstract

The cause of the death of a 16-month-old Brasileiro-de-Hipismo filly and a 3-year-old male Paint Horse with clinical manifestations of anemia and apathy from southern Brazil was investigated. These horses were maintained at the same stable; received hay as part of their diet and were submitted for routine necropsy evaluations. Significant gross findings included several nodules randomly distributed throughout the pulmonary lobes of both horses, and the kidneys, myocardium, and the frontal lobes of the cerebrum of the filly. Histopathological evaluation revealed pyogranulomatous bronchopneumonia in both horses; granulomatous interstitial nephritis, myocarditis, and encephalitis were observed in the filly. All lesions contained vasculitis and thrombosis associated with myriads of intralesional, branching, septate fungi consistent with Aspergillus spp.; intralesional fungi were more easily identified by the Grocott methenamine silver stain. Mycological culture of fresh pulmonary sections from both horses and the brain of the filly revealed pure growths of A. fumigatus. These findings confirmed the participation of A. fumigatus in the etiopathogenesis of the lesions observed in the lungs of both horses, and the cerebrum, myocardium and kidneys of the filly and might represent the first description of A. fumigatus-induced encephalitis in horses. Additionally, we believe that infection occurred during the ingestion of contaminated hay or by inhalation of spores within contaminated bedding that resulted in transient nasal mycosis, which progressed to pyogranulomatous bronchopneumonia in both horses with embolic encephalitic, myocardial, and renal dissemination of A. fumigatus occurring only in the filly.

Diphtheric aspergillosis tracheitis with gastrointestinal dissemination secondary to viral infections in a dairy calf

“…The intralesional fungal hyphae observed at the trachea, nasal cavity, rumen, and colon by routine histopathology and better visualized with the histochemical stain are consistent with previous descriptions of Aspergillosis -induced diseases in veterinary [ [31] , [32] , [33] , [34] , [35] ] and human [ [10] , [11] , [12] , 36 ] medicine. Moreover, speciation to A. fumigatus was confirmed due to morphological characteristics observed from the specimens subjected to mycological evaluation; similar morphologic findings were described [ [37] , [38] , [39] ].…”

“…Consequently, adequate mycological evaluation by experienced professionals can result in the diagnosis of A. fumigatus from tissues using classical mycology [ 41 ], without the need for molecular methods. Similar diagnostic strategies for aspergillosis were reported in horses [ 31 , 35 ]. Additionally, the intralesional identification of BVDV and MCFV antigens in multiple tissues and restricted identification of BoHV-1 antigens at the trachea demonstrated that this calf was infected by these viral pathogens, confirming four concomitant infections in this animal.…”

“…While immunosuppression due to BoHV-1 has been associated with the infection of lymphocytes and apoptosis of CD4 cells [ 44 ]. Moreover, the utilization of corticosteroids and/or antibiotics were predisposing factors relative to the occurrence of disseminated aspergillosis in a cow [ 45 ] and horses [ 31 , 46 ]. Consequently, the antibiotic therapy to which this calf had been subjected could have also contributed for the occurrence of aspergillosis; antibiotic therapy seems to predispose ruminants to infections by A. fumigatus [ 1 , 3 ].…”

“…On arrival at the pharynx, the fungal material probably suffered deglutition into the esophagus, finally arriving at the rumen resulting in necrotizing mycotic rumenitis. Hematological dissemination would then producing fungal colitis; hematological spread was also related to disseminated aspergillosis in a cow [ 45 ] and horses [ 31 ].…”

Gliotoxin – bane or boon?

“…The high temperature environment during the maturation along with the relative humidity is a perfect habitat for thermotolerant organisms like A. fumigatus , which could finally lead to a contamination of the food stock and entry to the food chain. The fact that horse and poultry feed samples had the greatest contamination frequency (Pena et al ., ) might explain the infection of horses (Hilton et al ., ; Headley et al ., ) and turkey poults with A. fumigatus . The isolates from different tissues showed the ability to produce GT.…”