Walter Tarello
Pet Connection Veterinary Clinic, P.O. Box450288, Dubai, UAE
Correspondence should be addressed to Walter Tarello, wtarello@yahoo.it
Received 14 February 2011; Accepted 19 April 2011 Academic Editor: Todd R. Callaway
1. Introduction
Aspergillosis is considered the most common systemic mycosis in birds [1] and the most important cause of death in captive falcons [2,3]. Infections with Aspergillus fumigatus and, less commonly, with A. flavus, A. terreus, and A. niger apparently share the same clinical importance in raptors held in captivity [4]. Clinical signs in birds are nonspecific and include reduction in appetite, weight loss, dyspnoea, lethargy, and death [5].
Avian aspergillosis involves mainly the lower respiratory tract [6]. This also occurs in falcons, in which the majority of reported cases are isolated from the air sacs [4]. These fungi are ubiquitous, but they become pathogenic mainly under stressful conditions, producing opportunistic infections as a result of inhalation of Aspergillus spores coupled with compromised immune functions in the host or in association with prolonged diseases [6-8]. Poor ventilation, malnutrition, toxins, vaccinations, long-term use of antibiotics and corticosteroids, hot-humid climate, and stress-associated conditions, such as recent capture, training, and change of ownership, are frequently mentioned as environmental precipitating factors influencing the onset and duration of aspergillosis in falcons [7-10].
Unfortunately, what actually causes immunosuppression and/or prolonged disease is rarely mentioned in the literature, because dual or multiple infections with potentially immunocompromising or chronically persistent pathogens (i.e., Mycobacterium spp., Babesia shortti, and Serratospicu-lum sp. nematode) are only sporadically recorded in raptors [11, 12] and other birds with aspergillosis [8, 13]. It is not clear whether these infections are truly rare, underdiagnosed, diagnosed but underestimated, or simply rarely reported.
Thus, it seemed important to assess to what extent the involvement of concurrent agents occurs in the condition. This study provides a list of the pathogens recorded recently in 94 captive falcons from Dubai with a definitive diagnosis of aspergillosis and compares their prevalence with a control group of 2000 randomly chosen diseased falcons without clinical, biochemical, and endoscopic evidence of aspergillo-sis.
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