Identification of pathogenic Aspergillus isolates from captive birds in Australia

Aspergillosis in Wild Birds

The ubiquitous fungi belonging to the genus Aspergillus are able to proliferate in a large number of environments on organic substrates. The spores of these opportunistic pathogens, when inhaled, can cause serious and often fatal infections in a wide variety of captive and free-roaming wild birds. The relative importance of innate immunity and the level of exposure in the development of the disease can vary considerably between avian species and epidemiological situations. Given the low efficacy of therapeutic treatments, it is essential that breeders or avian practitioners know the conditions that favor the emergence of Aspergillosis in order to put adequate preventive measures in place.

Case report of respiratory aspergillosis and candidiasis in wild Magellanic penguins (Spheniscus magellanicus), Brazil

Magellanic penguins (Spheniscus magellanicus) migrate to the continental shelf of southern-southeastern Brazil during austral winter. Stranded penguins are directed to rehabilitation centers, where they occasionally develop fungal diseases. Aspergillosis, a mycosis caused by Aspergillus spp., is one of the most important diseases of captive penguins, while Candida sp. has been detected in penguins undergoing rehabilitation. Nevertheless, their occurrence in the wild is poorly understood. This study surveyed the occurrence of mycoses in free-ranging Magellanic penguins wintering in southeastern Brazil. These penguins were either found dead or stranded alive and died during transport to a rehabilitation center. Overall, 61 fresh to moderate autolyzed carcasses were necropsied. Upon necropsy, three juvenile males (4.9%) presented mycotic-consistent gross lesions. Histopathology and panfungal PCRs confirmed the mycoses. Major microscopic findings were marked chronic necrotizing multifocal to coalescent pneumonia, airsacculitis, and esophageal/gastric serositis with two types of intralesional fungal structures: (a) septated acute-angled branching hyphae (n = 2) and (b) yeast structures (n = 1), both PAS- and Grocott-positive. Sequences identical to Aspergillus sp. were retrieved in two cases, while the third had sequences identical to Candida palmioleophila. This study describes two cases of aspergillosis and one of candidiasis in free-ranging Magellanic penguins, confirming the species' susceptibility in the wild. These mycoses could be associated with the animals' poor body condition, and/or impaired immunity, and natural and anthropogenic challenges related to migration. To the authors' knowledge, this is the first report of aspergillosis in free-ranging Magellanic penguins in the Atlantic Ocean and of candidiasis in penguins worldwide.

Aspergillosis, Avian Species and the One Health Perspective: The Possible Importance of Birds in Azole Resistance

The One Health context considers health based on three pillars: humans, animals, and environment. This approach is a strong ally in the surveillance of infectious diseases and in the development of prevention strategies. Aspergillus spp. are fungi that fit substantially in this context, in view of their ubiquity, as well as their importance as plant pathogens, and potentially fatal pathogens for, particularly, humans and avian species. In addition, the emergence of azole resistance, mainly in Aspergillus fumigatus sensu stricto, and the proven role of fungicides widely used on crops, reinforces the need for a multidisciplinary approach to this problem. Avian species are involved in short and long distance travel between different types of landscapes, such as agricultural fields, natural environments and urban environments. Thus, birds can play an important role in the dispersion of Aspergillus, and of special concern, azole-resistant strains. In addition, some bird species are particularly susceptible to aspergillosis. Therefore, avian aspergillosis could be considered as an environmental health indicator. In this review, aspergillosis in humans and birds will be discussed, with focus on the presence of Aspergillus in the environment. We will relate these issues with the emergence of azole resistance on Aspergillus. These topics will be therefore considered and reviewed from the “One Health” perspective.

Rhinitis due to Aspergillus pseudoviridinutans in an orange-winged Amazon parrot (Amazona amazonica)

Species within the Aspergillus viridinutans complex are being increasingly recognized as pathogens of animals and humans. An orange-winged Amazon parrot (Amazona amazonica) was referred for a 6 month-history of a slowly developing swelling involving the right nostril. Abnormal physical exam findings included a mild firm swelling at the dorsolateral aspect of the right nostril with no nasal discharge. Computed tomographic examination showed mild deformation of the right naris and nasal conchae without distinct granuloma. A cryptic Aspergillus species in Aspergillus section Fumigati was cultivated and identified by PCR and comparative sequence analysis as Aspergillus pseudoviridinutans. Successful treatment was achieved using topical clotrimazole and systemic antifungals (itraconazole, terbinafine). This is the first report of A. pseudoviridinutans infection in a bird.

Migratory birds as the potential source for the transmission of Aspergillus and other fungus to Bangladesh

Objectives

Migratory birds play a major role in the transmission of pathogens globally, but still their role in the transmission of fungi in Bangladesh is not known. The present study was carried out for the isolation and molecular detection of fungi including Aspergillus from migratory birds traveling to Bangladesh.

Materials and methods

A total of 50 fecal samples were collected from BaojaniBaor, Magura, and areas close to Jahangirnagar University, Savar. The isolation of fungus was based on culture on Potato Dextrose Agar (PDA), followed by staining, morphology, and molecular detection using polymerase chain reaction (PCR).

Results

Among 50 samples, 40 showed positive for fungal growth on PDA, of which 30 yield only yeast-like colonies, five only molds, and five yielded both yeast and molds. The isolated molds produced various pigmented colonies, namely, black, whitish, grayish, olive green, and yellow. Among 10 molds, six were confirmed as fungi by PCR using genus-specific primers such as ITS1 and ITS4. Later, of these six fungi, five were confirmed as Aspergillus by PCR with primers such as ASAP1 and ASAP2 specific for Aspergillus genus. Therefore, the overall occurrence of Aspergillus was 10% (5/50). PCR specific for Aspergillus fumigatus and Aspergillus niger failed to produce specific PCR amplicon, suggesting that the isolated Aspergillus belongs to other groups.

Conclusion

This is the first report describing the isolation and molecular detection of Aspergillus from fecal samples of migratory birds in Bangladesh. The present findings confirm that migratory birds are potential source for Aspergillus and other fungus in Bangladesh.

Aspergillosis in free-ranging aquatic birds

Due to the difficulty in the access to free-ranging birds, data regarding Aspergillus infections in wild avian species is rare compared to captive wild and domestic birds. Objective: report three cases of Aspergillus section Fumigati causing fungal disease in free-ranging aquatic birds, with the identification of the causal agent to the species level. Case reports: The diagnosis of aspergillosis was performed by macroscopic lesions found during the necropsy and confirmed by culture. Molecular identification by partial sequencing of the calM and benA genes allowed to confirm Aspergillusfumigatussensustricto as the etiological agent of aspergillosis in Procellariaaequinoctialis (White-chinned petrel) (n = 1), Nannopterumbrasilianus (Neotropical cormorant) (n = 1) and Chroicocephalusmaculipennis (Brown-hooded gull) (n = 1). Conclusion: Larger studies regarding the importance of aspergillosis in free-ranging aquatic birds are necessary, as well as it potential role in the One Heath context.

Application of different pharmacokinetic models to describe and predict pharmacokinetics of voriconazole in magellanic penguins following oral administration

Aspergillosis is a condition causing serious morbidity and mortality in captive penguins and other bird species. It can be treated with antifungal drugs, such as voriconazole. However, the pharmacokinetics of voriconazole are variable between different animal and bird species. Therefore, the pharmacokinetics of voriconazole were investigated in this study in Magellanic penguins. Pharmacokinetic models were constructed and applied to predict the pharmacokinetics of voriconazole during long-term treatment in Magellanic penguins, since the voriconazole treatment duration in chronic aspergillosis cases can last up to several months. Plasma voriconazole concentration-time data from adult Magellanic penguins (Spheniscus magellanicus; n = 15) following a single oral (PO) dose of either 2.5 mg/kg or 5 mg/kg in a herring in three separate study periods 7-12 months apart were collected. Mean plasma voriconazole concentrations were above the targeted MIC for Aspergillus fumigatus for 2 hr following a single 2.5 mg/kg voriconazole dose while the plasma concentrations exceeded the MIC for least 24 hr following a 5 mg/kg dose. Nonlinear mixed-effects modeling was used to fit two pharmacokinetic models, one with first-order and another with saturable elimination, to the single-dose data. Fits were good for both, as long as dose was included as a covariate for the first-order model so that clearance was lower and the half-life longer for animals receiving the 5 mg/kg dose. Although the single-dose data suggested saturated elimination at higher concentrations, the model with saturable elimination did not predict plasma voriconazole concentrations well for a clinical aspergillosis case receiving long-term treatment, possibly because of induction of metabolizing enzymes with chronic exposure. Pharmacokinetic models should accurately predict plasma drug concentrations for different dosage regimens in order to be applicable in the field. Future studies should focus on determining clearance at steady-state to be able to refine the pharmacokinetic models presented here and improve model performance for long-term oral voriconazole administration in Magellanic penguins.