Diphtheric aspergillosis tracheitis is an uncommon syndrome described in human pathology, usually associated with immunosuppression in the affected individuals. Interestingly, no comparative/equivalent cases were found in domestic animals. This report describes the pathological and mycological findings associated with diphtheric aspergillosis tracheitis in an immunocompromised calf. The main pathological findings were diphtheric tracheitis and rhinitis, and necrotizing ruminitis associated with intralesional septate, acute branching fungal hyphae consistent with Aspergillus spp. Mycological culture and isolation confirmed the fungal hyphae as A. fumigatus due to characteristic features. Immunohistochemistry (IHC) assays identified intralesional antigens of bovine viral diarrhea virus (BVDV) and malignant catarrhal fever virus (MCFV) at the trachea and small intestine; IHC detected intralesional antigens of bovine alphaherpesvirus 1 (BoHV-1) only at the trachea. These findings confirmed the simultaneous occurrence of A. fumigatus with concomitant infections due to BVDV, MCFV, and BoHV-1 in this calf. Since ovine gammaherpesvirus-2 (OvHV-2) is the cause of MCF in Brail, it is likely that the intralesional MCFV antigens identified were those of OvHV-2. In this case, disseminated aspergillosis was probably associated with the undeveloped immunological status of the calf that was further impaired due to the combined immunodepressive effects of BVDV and BoHV-1 infections. Although BVDV and BoHV-1 are infectious disease pathogens frequently associated with the development of bovine respiratory disease (BRD) in feedlot and dairy cattle, the identification of intralesional OvHV-2-like antigens in several parts of the lungs suggest that this MCFV also played a role in the BRD-associated lesions identified in this calf.

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Maedi-Visna (MV) is a chronic progressive multisystem disease that may be asymptomatic for several months or years, but progress rapidly, and may result in death, when signs and symptoms evolve. Viral elimination occurs mainly through direct contact with positive animal secretions. There is no vaccine or treatment, and prophylaxis is necessary for the health of the herd. The present study aimed to verify the seropositivity of MV and evaluate the factors associated with the risk in sheep herds in Paraná. A total of 1549 serum samples were collected from 90 properties. An epidemiological questionnaire was applied to each property, and the variables were analyzed using the Epi-info program and R environment. Of the 1549 samples analyzed, 22 were positive (1.4%) for the micro-AGID test in 13.3% of the properties. Our study demonstrated variables associated with the prevention and the risk of seropositivity to MVV. Conducting a breeding season, supplying concentrated feed, and separating the breeding stock before birth were factors associated with protection, whereas the previous occurrence of problems with lice, breeding on pasture, and keeping cats close to the flock were factors associated with risk. The seropositivity observed in the present study suggests the circulation of MVV in sheep herds in Paraná, which reinforces the need to implement prevention and control measures since the level of technification may be associated with the occurrence of anti-MVV antibodies in herds.