Most cats in the world are infected by B. henselae at some point in their lives, usually when they are kittens less than a year old. It doesn’t cause them any problems at all, except very rarely. They catch it from fleas that have picked it up from another cat. They can also catch it directly from an infected cat if they have been fighting.
Most people who get cat scratch disease have caught it from a cat and can remember a scratch, bite or a lick from a cat in the previous week to two months. Very occasionally the affected person doesn’t remember any contact with a cat.
It is possible they have caught it from an infected cat flea. Some people think it can be caught from other animals such as dogs and rabbits, but this hasn’t been proven.
