Aspergillosis, a disease caused by infection with Aspergillus spp., is a common cause of death in birds globally and is an irregular cause of mortality of captive kiwi (Apteryx spp.). Aspergillus spp. are often present in rotting plant material, including the litter and nesting material used for kiwi in captivity. The aim of this study was to survey nocturnal kiwi houses in New Zealand to assess the levels of Aspergillus currently present in leaf litter. Samples were received from 11 nocturnal kiwi houses from throughout New Zealand, with one site supplying multiple samples over time. Aspergillus was isolated and quantified by colony counts from litter samples using selective media and incubation temperatures. Isolates were identified to the species level by amplification and sequencing of ITS regions of the ribosomal. Aspergillus spp. were recovered from almost every sample; however, the levels in most kiwi houses were below 1000 colony-forming units (CFU)/g of wet material. The predominant species was Aspergillus fumigatus, with rare occurrences of Aspergillus niger, Aspergillus nidulans, and Aspergillus parasiticus. Only one site had no detectable Aspergillus. The limit of detection was around 50 CFU/g wet material. One site was repeatedly sampled as it had a high loading of A. fumigatus at the start of the survey and had two recent clinical cases of aspergillosis diagnosed in resident kiwi. Environmental loading at this site with Aspergillus spp. reduced but was not eliminated despite changes of the litter. The key finding of our study is that the background levels of Aspergillus spores in kiwi nocturnal houses in New Zealand are low, but occasional exceptions occur and are associated with the onset of aspergillosis in otherwise healthy birds. The predominant Aspergillus species present in the leaf litter was A. fumigatus, but other species were also present. Further research is needed to confirm the optimal management of leaf litter to minimize Aspergillus spore counts. However, in the interim, our recommendations are that leaf litter should be freshly collected from areas of undisturbed forest areas and spread immediately after collection, without interim storage.
Aislamiento e identificación de Aspergillus spp. de alojamientos nocturnos de kiwi marrón (Apteryx mantelli) en Nueva Zelanda.
La aspergilosis, enfermedad causada por la infección con Aspergillus spp., es una causa común de muerte en las aves a nivel mundial y es una causa no regular de mortalidad de kiwis en cautiverio (Apterix spp.). El Aspergillus spp. está a menudo presente en la descomposición de la material vegetal , incluyendo la cama y el material utilizado para la anidación del kiwi en cautiverio. El objetivo de este estudio fue examinar los alojamientos nocturnos de kiwis en Nueva Zelanda para evaluar los niveles de Aspergillus actualmente presentes en la cama de hojas. Se recibieron muestras de 11 alojamientos nocturnos de kiwi de toda Nueva Zelanda, con un sitio que suministró múltiples muestras con el tiempo. Se aisló y se cuantificó Aspergillus por recuento de colonias de las muestras de cama usando medios selectivos y temperaturas de incubación. Los aislamientos fueron identificados a nivel de especie mediante amplificación y secuenciación de regiones ribosomales ITS. Se recuperó Aspergillus spp. de casi todas las muestras, sin embargo, los niveles en la mayoría de los alojamientos de kiwi estaban por debajo de las 1000 unidades formadoras de colonias (UFC )/g de materia húmeda. La especie predominante fue Aspergillus fumigatus, con presentaciones poco frecuentes de Aspergillus niger, Aspergillus nidulans y Aspergillus parasiticus. Sólo un sitio no mostró Aspergillus detectable. El límite de
