Table of Contents

Whole Allergen

e213 Parrot feathers

e213 Parrot feathers Scientific Information

Type:

Whole Allergen

Display Name:

Parrot feathers

Allergen code:

e213

Family:

Psittacidae

Species:

Ara spp.

Route of Exposure:

Inhalation

Latin Name:

Ara spp.

Other Names:

Parrot

WHO/ICD-11 code:

XE69N

(ICD-11 is currently under implementation by WHO and the ICD-11 codes displayed in the encyclopedia may not yet be available in all countries)

Summary

Parrots are a group of colorful tropical bird species popular as pet birds. Most parrot species are found in tropical and sub-tropical forests across Central and South America, Australasia, Oceania, and Africa. Parrots are found to nest in holes and prefer to reside in wetter environments and warm regions. Some parrot blooms are found to be responsible for transporting soluble antigens to the lower airways and, therefore, can act as an adjuvant, enhancing the immunogenic reaction. Exposure to parrot feathers has been found to be associated with the bird-egg syndrome, asthma, allergic rhinitis, rhinoconjunctivitis, and hypersensitivity pneumonitis. Studies with parrot feather extract have reported the presence of few allergenic protein bands. Cross-reactivity is found between sera and feathers of bird species, including parrots, the canary, goose, hen, duck, and pigeon. Furthermore, budgerigar feather extract (containing albumin) is reported to be cross-reactive with egg yolk extract (containing Gal d 5).

Allergen

Nature

The Psittaciformes order includes 370 species and 576 subspecies as per the ITIS database (1). Parrots (belonging to the order Psittaciformes) are reported as a group of colorful tropical bird species, which exhibit distinctive feather colors (2) and are very popular pet birds (3). These birds possess a typical, well-developed upper beak (hooked rostrum) along with an adjacent featherless portion (cere). The upper beak in large parrots (e.g., macaws) is joined to the skull via a synovial joint. However, in smaller parrots (e.g., budgerigars), this joint is connected through an elastic zone (3).

Taxonomy

The birds belonging to the order Psittaciformes include parrots, macaws, cockatoos, and lories (3).

Taxonomic tree of Parrot feathers (4)
Domain	Eukaryota
Kingdom	Metazoa
Phylum	Chordata
Subphylum	Vertebtata
Class	Aves
Order	Psittaciformes
Family	Psittacidae
Genus	Ara
Species	Ara spp.

Tissue

Allergenic proteins are reported to be present in the bird’s feather bloom, droppings, and skin scales. Some parrots, including parakeets, budgerigars, and cockatiels, produce large blooms, where keratin granules are reported to be responsible for transporting the soluble antigens to the lower airways and can act as an adjuvant, enhancing the immunogenic reaction (5).

Epidemiology

Worldwide distribution

In a study from an allergic population in Venezuela, serum specific-IgE (sIgE) to parrot feathers were observed in 24 out of 189 allergic patients with allergic rhinitis and/or asthma (6).

Occupational allergy to birds has been reported as one of the significant health issues among zoo bird keepers, which was addressed in a study involving Polish zoo employees (Swiderska-Kielbik, Krakowiak et al. 2011). The study assessed 200 bird zookeepers where allergen-sIgE against any bird allergen was found in 72 % of subjects, and sIgE against parrot feathers was detected among 25 % of the subjects (7)

Environmental Characteristics

Living environment

Parrots nest in holes and prefer to reside in wetter environments and warm regions (3, 8).

Worldwide distribution

Most parrot species are found in tropical and sub-tropical forests across Central and South America, Australasia and Oceania, and Africa (9).

Route of Exposure

Main

Inhalation of parrot feathers dust is considered the route of exposure that can trigger immunological reactions (5, 10).

Clinical Relevance

Allergy to parrots has been reported to be associated with rhinoconjunctivitis, asthma, allergic rhinitis, bird-egg syndrome, and bird fancier’s lung (11-15).

Asthma, allergic rhinitis, and rhinoconjunctivitis

Bronchial asthma, allergic rhinitis, and rhinoconjunctivitis may result from exposure to budgerigar feathers, serum, or droppings (11, 15).

Bird-egg syndrome

Bird-egg syndrome (typically based upon sensitization to bird allergens and allergic symptoms occurring after egg consumption) has been reported in adults due to sensitization to avian airborne allergens through feathers, sera, and droppings of pet birds, including parrots (12).

Bird fancier’s lung

Bird fancier’s lung is a common type of hypersensitivity pneumonitis triggered by frequent exposure to avian aeroantigens (including proteins present on the feathers and excreted in bird droppings) (13, 14).

In a study involving patients with bird fancier’s asthma, the highest sIgE antibody binding was observed among bird fanciers (the bird caregivers) who had contact with the feathers of the bird species, including parrots (10).

Prevention and Therapy

Prevention strategies

Avoidance

Completely avoiding the antigen source is considered the primary measure to reduce the amount of antigen in the respiratory system (12, 16). Additionally, patients are also suggested to thoroughly clean their house and install HEPA air cleaner (17).

Molecular Aspects

Allergenic molecules

To date (22-SEP-2021), no allergenic molecule has been identified from parrot feathers according to the WHO/IUIS (18).

However, a study has found well-defined major allergenic bands (through IgE immunoblots; 20-30 kDa and 67 kDa) with feather extracts and serum proteins of parrot, budgerigar, canary, pigeon, and hen (10).

Furthermore, another study found a 70 kDa allergenic protein band (based on IgE immunoblotting) with budgerigar (parrot) feather extract corresponding to the budgerigar serum albumin (12).

Cross-reactivity

Cross-reactivity was seen between sera and feathers of the tested bird species (including the parrot, canary, goose, hen, duck, and pigeon) in patients with bird fancier’s asthma (10).

Cross-reactivity was seen between egg yolk extract (Gal d 5; livetin) and budgerigar feather extract containing albumin (12).

Compiled By

Author:Turacoz Healthcare Solutions

Reviewer: Dr. Christian Fischer

Last reviewed: March 2022

References

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Swiderska-Kielbik S, Krakowiak A, Wiszniewska M, Nowakowska-Swirta E, Walusiak-Skorupa J, Sliwkiewicz K, et al. Occupational allergy to birds within the population of Polish bird keepers employed in zoo gardens. Int J Occup Med Environ Health. 2011;24(3):292-303.
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