Science Questions

How does cat saliva cause allergies?

In your programme about allergies, you mentioned that the cause of cat allergy is the saliva in their skin. Could you please clarify whether this means saliva when a person is licked by a cat, by petting the cat after they've licked themselves, or a secretion from their skin with no physical touching needed? David via email

People are reacting to a substance made by a gene called FelD1. It's produced in cat saliva, so that when a cat licks itself and its paws and grooms itself with a wet paw, this FelD1 product or protein then goes onto the fur and when it sheds that protein with its fur, it goes into your nose and makes people sneeze. There's a company over in California and they've bred a type of cat that doesn't have that particular part of that gene and they say, although it hasn't been proven scientifically yet, that it's actually non-allergenic.

October 2006