Hello, since CLL causes a progressive immunodeficiency, caution is advised when coming into contact with potential pathogens. Immune system deficiency means that even harmless bacteria may cause an overwhelming infection. Being scratched by cats is not the only way to contract an infection. I ll mention some basic advice regarding pet owners. - regular veterinarian checks on your pets - vaccination - minimize their outdoors - do not feed them with raw meat - wash your hands after contacting them I hope I ve helped! You can contact me again, if you d like more information or clarifications. Kind Regards!