An exclusion found within professional liability insurance policies that precludes coverage for claims caused by the transmission of communicable diseases. The wording of this exclusion usually consists of two parts. The first part excludes coverage for claims caused by a the refusal to treat a person who has (or is suspected of having) a communicable disease. The second part of the exclusion eliminates coverage for claims in which a client alleges that an insured caregiver transferred a communicable disease to the client.