e211 Rabbit urine proteins

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The Common European Rabbit is native to Southern Europe and Africa, but is now found, in its domestic varieties, throughout the world; wild varieties have also been introduced in some places, such as England. All Domestic Rabbits, belong to this species. They may be various colours but are commonly white, and are bred for food and for their fur, which is often used in making fur trim and felt. They are also frequently used as laboratory animals and are kept as pets. Wild Rabbits feed on a wide variety of vegetation and are responsible in many areas for the stunted nature of the ground cover.

IgE mediated reactions
Of the 90,000 laboratory animal workers in the United States, between 21% and 46% develop allergy to laboratory animals. Of those who develop symptoms, more than 10% eventually develop occupation-related asthma with symptoms that persist even after exposure ceases (6, 8, 9). These individuals are susceptible to life-threatening (but rare) anaphylactic reactions following animal bites and scratches and pricking with needles contaminated with the animal proteins (8).

Many animals associated with laboratories may actually be adopted as pets, resulting in allergies in their owners and other family members.

Allergy to animals may range from allergic rhinitis to allergic conjunctivitis to dermatitis to severe asthma. These may result from the inhalation of or contact with the animal's dander, epithelium cells, urine, saliva, serum or hair. Most animals shed allergens through these substances, but not all species or strains do so equally. Different routes of exposure, e.g., respiratory, oral, mucosal and transdermal, elicit different symptoms.

A large study of laboratory animal workers in Japan recorded that symptoms were reported in 26% of workers exposed to Mice, 25% for Rats, 31% for Guinea Pigs, 30% for Rabbits, 26% for Hamsters, 30% for Cats, 25% for Dogs and 24% for Monkeys. About 70% of laboratory animal allergy (LAA) subjects developed symptoms during their first three years of exposure. A close relation between nasal symptoms and exposure to Rabbits, and between skin symptoms and exposure to Rats, were found. LAA subjects developed symptoms most quickly to Rabbits (10). The commonest symptom is allergic rhinoconjunctivitis with nasal congestion, rhinorrhoea, sneezing and itchy, watery eyes, which can occur in up to 80% of symptomatic workers (5).

While Rabbits are common as pets, severe allergic reactions to domestic Rabbits in homes are unusual. Typically, allergic manifestations are mild to moderate allergic rhinitis, conjunctivitis, pruritus and/or asthma, contact urticaria and contact dermatitis in laboratory animal caretakers with frequent exposure (4, 11-12). In a study of atopic children with contact with pets, 18% were sensitised to Rabbit and 12.3% showed clinical signs in the animal's presence (13). Cumulative duration of exposure to domestic animals is a significant determinant for immediate sensitisation to animal-derived antigens in subjects with asthma (12).

In a cross-sectional survey carried out on 138 workers exposed to laboratory animals, 60 (44%) had symptoms, as shown in a self-completed questionnaire, that were consistent with laboratory animal allergy (LAA); of these individuals, 15 (11%) had chest symptoms. There was a positive skin-prick test to one or more animal urine extracts (Rat, Mouse, Guinea Pig, Rabbit) in 13%, and 38% had a positive specific IgE test to urine extract (14).

Several allergens have been identified in Rabbit saliva, fur, urine, dander and dust, but most have not been fully characterised yet (1-4).

Ory c 2, found in hair, dander and urine (5-6).

Serum-specific IgE results suggest that epithelium has different allergens from those in saliva, urine and fur. Saliva is the most potent extract. Overall, 26 protein bands are recognised as allergens. Saliva has 12, urine 7 and fur 7. Molecular weights varied from 8 kDa in saliva to 80 kDa in urine. An 18 kDa and 21 kDa protein were shown to belong to the lipocalin family. Saliva appears to contain the most potent allergen, which probably has a high homology with a 21 kDa lipocalin-odorant binding protein from Rabbit nasal mucosa (5-7).

Last reviewed- April 2022