Diagnosis of Aspergillosis in Horses

Abstract

Invasive pulmonary aspergillosis (IPA) may be a rare cause of granulomatous pneumonia in horses. The mortality of IPA is almost 100%; direct diagnostic tools in horses are needed. Bronchoalveolar lavage fluid (BALF) and serum samples were collected from 18 horses, including individuals suffering from IPA (n = 1), equine asthma (EA, n = 12), and 5 healthy controls. Serum samples were collected from another 6 healthy controls. Samples of BALF (n = 18) were analyzed for Aspergillus spp. DNA, fungal galactomannan (GM), ferricrocin (Fc), triacetylfusarinin C (TafC), and gliotoxin (Gtx). Analysis of 24 serum samples for (1,3)-β-D-glucan (BDG) and GM was performed. Median serum BDG levels were 131 pg/mL in controls and 1142 pg/mL in IPA. Similar trends were observed in BALF samples for GM (Area under the Curve (AUC) = 0.941) and DNA (AUC = 0.941). The fungal secondary metabolite Gtx was detected in IPA BALF and lung tissue samples (86 ng/mL and 2.17 ng/mg, AUC = 1).

Pulmonary aspergillosis in a horse: a case report

“…Clinicians must take care in attributing significance to the presence of fungal elements, free or in large quantity, in transtracheal aspirate fluid, as they are commonly identified in healthy horses or horses with severe asthma (Dobiáš et al, 2023). The fungal elements found in the transtracheal lavage should not be considered clinically relevant whenever accompanied by a normal predominance of macrophages, lymphocytes, and nondegenerate neutrophils (Stewart & Cuming, 2015), contrasting with the findings of degenerated neutrophils found in this report.…”

“…One hypothesis for the development of pulmonary aspergillosis in the present report is the possibility that this fungal infection was facilitated by the clinical condition of asthma, as previously suspected in clinical examinations. Dobiáš et al (2023) demonstrated that the trachea could be massively colonized by Aspergillus species, especially in individuals with severe asthma. Both in this report and in that of Moreira et al (2004) it is likely that both animals presented a fungal pulmonary condition at the beginning of its evolution secondary to equine asthma.…”

“…Aspergillus spp. infections cause many diseases, from localized to fatal disseminated invasive infections in humans and animals (Dobiáš et al, 2023). In animals, aspergillosis is predominantly a respiratory infection that may subsequently develop into a systemic condition (Hattab et al, 2021).…”