In the illustrations below, you can find all the possible transmission routes for the most common feline diseases.
In every case, prevention is the most important thing you can do.

When it comes to vector transmissions, proper prevention against internal and external parasites is key.
When it comes to oral transmission, vaccines can protect your cat against some of the diseases. For the rest, early detections of symptoms and seeking veterinary care is key.
If your cat is sick at the moment, limit his or her contact with other cats.
And always keep an eye on your cat when he/she goes outside????