Avian Aspergillosis: Treatments & Acquired Immunity

By Team Beauty of Birds

by Dr. Tara Nath Gaire

Department of Veterinary Medicine and Public Health
Institute of Agriculture and Animal Science (IAAS), Rampur, Chitwan, Nepal.

Complete Article: Avian Aspergillosis by Dr. Tara Nath Gaire

Contents

Abstract … Introduction … Etiology … Growth … Toxins … Epidemiology … Transmission … Pathogenesis … Clinical Signs, Gross Lesions, Histopathology & Diagnosis … Treatments & Acquired Immunity (below) … Prevention and Control … References Cited

Treatments

Treating avian aspergillosis is a challenge due to a number of factors. These include the limited knowledge on the pharmacokinetics of antifungal agents in different bird species, the granulomatous inflammation that makes it difficult for the drug to reach the target fungus, the presence of concurrent disease and/or immunosuppression, and the late stage at which birds are usually presented (McMillan & Petrak, 1989; Flammer, 1993; Orosz & Frazier, 1995). The best way to overcome the disease is topical therapy after removing the granulomatous tracheal lesions by suction (Westerhof, 1995), and this can be used in combination with an early, aggressive systemic antifungal therapy. In most birds, however, granulomatous lesions are difficult to remove because of their location within the respiratory system and because of the risk of surgical trauma and anaesthesia (Hernandez-Divers, 2002). Hence, in most cases, only antifungal therapy is applied. Topical therapy can be administered by nebulization, nasal or air sac flushing, or surgical irrigation of the abdominal cavities (Bauck et al., 1992; Oglesbee, 1997; Abrams et al., 2001), while systemic therapy can be administered intravenously and orally.

The role and prevalence of acquired resistance to antifungal drugs as a potential contributing factor is not well known. Since drug resistance has been increasingly reported in human medicine (Snelders et al., 2008), standardized susceptibility testing is also becoming necessary in avian medicine. Literature regarding in vitro susceptibilities of antifungal agents for avian A. fumigatus strains in birds is scarce. The minimal inhibitory concentration of thiabendazole, 5-fluorocytosine, fluconazole, ketoconazole, caspofungin, amphotericin B, itraconazole and voriconazole for a limited number of A. fumigatus strains isolated from raptors has been determined using non-standardized methods (Redig & Duke, 1985; Silvanose et al., 2006, 2009). Currently, a reference method is available to test the antifungal susceptibility of filamentous fungi (Clinical and Laboratory Standards Institute document M38-A2), thus solving the lack of standardization. Using this method, the in vitro susceptibility of 59 avian A. fumigatusstrains against amphotericin B, itraconazole and voriconazole has been determined. Four isolates showed acquired resistance to both itraconazole and voriconazole, a fact that may harbour implications for the treatment (Beernaert et al., 2009c).

 

Acquired Immunity

The role of acquired immunity in aspergillosis resolution still remains unclear. A previous nonfatal challenge with A. fumigatus did not protect turkeys against a second inoculation and even worsened airsacculitis severity. Transfer of activated splenocytes from convalescent 12-to-14-week-old Beltsville small white turkeys to naive birds did not confer any protection against experimental infection to the latter. A culture filtrate vaccine, a conidial vaccine, a mycelial vaccine, and 2 germling vaccines were compared in different trials for their protective efficiency against A. fumigatus infection in poults, with limited results. This underlines the actual importance of animal models in therapeutic protocols evaluation.

 

Information contained on this website is provided as general reference only. For application to specific circumstances, professional advice should be sought.

 

Please Note: The articles or images on this page are the sole property of the authors or photographers. Please contact them directly with respect to any copyright or licensing questions. Thank you.

The Avianweb strives to maintain accurate and up-to-date information; however, mistakes do happen. If you would like to correct or update any of the information, please send us an e-mail. THANK YOU!

Beautyofbirds.com:© Copyright Policies| Disclaimers | We respect your privacy: Site Privacy Policy | For questions or comments, please contact Website Administrator

Any content published on this site is commentary or opinion, and is protected under Free Speech. It is only provided for educational and entertainment purposes, and is in no way intended as a substitute for professional advice. Avianweb assumes no responsibility for the use or misuse of any of the published material. Your use of this website indicates your agreement to these terms.

Listing of Parrot Species

Bird Breeding

 

Popular Bird Species

 

Interesting Facts

 

The Smallest Bird Alive …

Birds that can hibernate for months: the Common Poorwill

The Oldest Parrot:

The ONLY Birds that Can Fly BACKWARDS …

The largest flying parrot species is …

The World’s Rarest Wild Parrot

The parrots that build “bird condominiums”

The Most Common Hawk in North America

The Eurasian Eagle Owl is World’s Largest Owl

The record holder for speaking most words:

  • Budgie (with over 1,700 words)

The Smartest Birds Alive?

  • The birds that go fishing with breadcrumbs!

The largest wild goose ever recorded

Photo of author

Team Beauty of Birds

Beautyofbirds.com's team of experts includes veterinarians, biologists, environmentalists and active bird watchers. All put together, we have over half a century of experience in the birding space.

You can meet our team here.