Diphtheric aspergillosis tracheitis with gastrointestinal dissemination secondary to viral infections in a dairy calf.
Microb Pathog 2020;
149:104497. [PMID:
32910985 PMCID:
PMC7476962 DOI:
10.1016/j.micpath.2020.104497]
[Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 12/11/2022]
Abstract
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.
An unusual presentation of fungal diphtheric tracheitis associated with Aspergillus fumigatus is described in a dairy calf.
A Malignant Catarrhal Fever Virus, most likely, OvHV-2, was associated with the development of pneumonia in this calf.
Simultaneous infections in dairy calves may be more frequent than previously reported.
OvHV-2 should be considered as a possible disease pathogen associated with the development of bovine respiratory disease.
The immunodepressive effects of BVDV and BoHV-1 were fundamental for the development of the fungal disease observed in this calf.
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