Nombre de messages : 20368
Date d'inscription : 17/05/2007
|Sujet: cat allergy Jeu 14 Mar - 9:01|| |
march 5th 2013
Cat allergy in humans is an allergic reaction to one or more of the five known allergens produced by cats. The most common of these are the glycoprotein Fel d 1, secreted by the cat's sebaceous glands and Fel d 4, which is expressed in saliva. An allergic reaction is a histamine reaction that is usually characterized by coughing, wheezing, chest tightening, itching, nasal congestion, rash, watering eyes, sneezing, chapped lips, and similar symptoms.
1 Cat allergens
3 Coping with allergies
3.1 Lower exposure
3.3 Allergy shots
3.4 Synthetic epitope vaccine
3.5 Cat Bathing
4 Hypoallergenic cats
5 Cat gender and color
6 See also
8 External links
Five cat allergens have been described in medical literature. The two major allergens are Fel d 1 (a secretoglobin) and Fel d 4 (a lipocalin). The minor allergens include Fel d 2 (an albumin), Fel d 3 (a cystatin), and cat IgA.
Fel d 4 is the product of the cat major urinary protein gene. It is primarily expressed in the submandibular salivary gland and is deposited onto dander as the cat grooms itself. A study found that 63% of cat allergic people have antibodies against Fel d 4.
Symptoms of an allergic reaction to cats include: swollen, red, itchy, watery eyes; nasal congestion, itchy nose, sneezing, chronic sore throat or itchy throat, coughing, wheezing, asthma, hay fever, hives or rash on the face or chest, or itchy skin. If a cat has scratched, licked, or bitten someone who is allergic to cats, redness will occur. Symptoms are often confused with a common cold.
Coping with allergies
Allergic reaction to cats can be lessened most successfully by minimizing exposure to the animals. That is not always a practical solution, and there are a number of other strategies that may aid an allergy sufferer.
Allergens are airborne and survive for months or even years by themselves, hence removing anything that can trap and hold the allergens (carpet, rugs, pillows) and cleaning regularly and thoroughly with HEPA filters and Air purifier systems reduces risk. Frequent hand washing, especially after handling the cat, and washing hands prior to touching eyes, nose, or mouth, and limiting the cat to the outdoors or barring the animal from certain rooms, such as the bedroom or other rooms where much time is spent, may also reduce allergic reactions.
Cat allergies can often be controlled with over the counter or prescription medications. Antihistamines and decongestants may provide allergy relief.
Some allergy sufferers find relief in immunotherapy, a periodic injection therapy designed to stimulate the body's natural immune responses to the cat allergens.
Synthetic epitope vaccine
The Synthetic epitope vaccine is an in-development vaccine to provide a long term vaccine for allergies.
Regularly bathing the cat may remove significant amounts of allergens from the fur. Furthermore, regularly brushing the cat will reduce the amount of loose fur (and its attached saliva) in the air. Feeding the cat a high quality diet with plenty of Omega-3 fatty acids will help keep the coat healthy and minimize dander.
A hypoallergenic cat is a cat that is less likely to provoke an allergic reaction in humans. Although the topic is controversial, with many studies showing statistically significant results, owners' experience and recent clinical studies suggest that Siberian cats, Russian Blue cats, Devon Rex and Cornish Rex cats, Abyssinian cats, Balinese cats, and several other breeds, especially females are likely to have low levels of Fel d 1, the main allergenic protein.
In 2006, the Allerca company announced the successful breeding of a line of hypoallergenic cats. However, no peer-reviewed studies have been done to confirm their claims and many scientists and consumers are skeptical of the company's assertions. The company has announced that on January 1, 2010 they will cease their breeding activities.
Another company, Felix Pets, also claims to be developing a breed of hypoallergenic cat.
Cat gender and color
Female cats produce a lower level of allergens than males, and neutered males produce a lower level of allergens than unaltered males. In 2000, researchers at the Long Island College Hospital found that cat owners with dark-colored cats were more likely to report allergy symptoms than those with light-colored cats. A later study by the Wellington Asthma Research Group found that fur color had no effect on how much allergen a cat produced
Nombre de messages : 20368
Date d'inscription : 17/05/2007
|Sujet: Re: cat allergy Jeu 14 Mar - 9:24|| |
Allergen-free cats – a breed apart
18:45 09 June 2006 by Jeff Hecht
For similar stories, visit the GM Organisms Topic Guide
A California company has turned to conventional breeding to deliver the non-allergenic kittens it promised two years ago. But allergists warn the new cats may still be something to sneeze at.
In 2004, Allerca, then based in Los Angeles, announced plans to genetically engineer cats so they would not produce the most common cat allergen, a protein called FEL D1 (See Doubts over plan for allergen-free cats). Now based in San Diego, Allerca has abandoned genetic engineering to focus on selectively breeding cats that lack the version of the FEL D1 protein that triggers allergic reactions.
A spokeswoman says the company will deliver the first 400 to 500 "GD" (for genetically divergent) kittens in 2007.
Allergists consider the approach scientifically plausible. "It's been known for a long time that some cats are very low allergen producers", producing just one-thousandth the FEL D1 of a normal cat, says Robert Wood, director of Pediatric Allergy and Immunology at the Johns Hopkins University School of Medicine in Baltimore, US.
Allerca says that is because those cats lack the gene to produce the allergenic form of FEL D1, and instead produces a different, non-allergenic protein. They genetically screened cats to identify low-FEL D1 animals for a breeding population.
In a statement, Allerca says "individuals with known feline allergies were fully exposed to the Allerca GD cats without demonstrating any allergic reactions", but that the same people suffered swollen eyes, asthmatic symptoms, and hives when later exposed to ordinary cats.
Cats are among the most common pets but also among the most widely blamed for allergic reactions because FEL D1 is the most potent pet allergen. Specific to cats, FEL D1 is found in fur, saliva, urine, and skin glands. Worse, it sticks to furniture, carpets and clothing, triggering allergies even when the cat is absent. Allergists typically tell people with severe asthma or allergies to get rid of cats to ease their symptoms.
But some still want pets. Allerca reports a two-year backlog of orders, with US residents paying $3950, and residents of other countries paying €4950 to €9950 ($6300 to $12,700, respectively). Kittens are to be shipped at 12 weeks old. "It's plausible that some people could benefit - if they have $4000 for a cat," Wood says.
The original breeding stock was based on the Shorthair breed, but Allerca says the current stock is closest to the Ragamuffin breed.
But allergies are tricky, and specialists are cautious about the prospects. "This approach is scientifically valid, but that doesn't mean it's going to work," says Norman Edelman, chief medical officer of the American Lung Association.
Although FEL D1 is the dominant cat allergen, Wood told New Scientist that about 10% of people with cat allergies react to cat albumin, a protein released in increasing amounts in the urine as the cat ages.
Another concern is that allergic reactions are notoriously sensitive and can vary widely. Wood has found that reducing allergen exposure by 75% does not reduce symptoms in sensitive people. "Individual sensitivity varies well over a hundred-fold," he says, so breeding "may not reduce FEL D1 enough to protect the most sensitive people."