rickettsialpox: mild infectious rickettsial disease caused by a bacterium of the genus Rickettsia transmitted to humans by the bite a mite that lives on rodents; characterized by chills and fever and headache and skin lesions that resemble chickenpox
rickettsial disease: infectious disease caused by ticks or mites or body lice infected with rickettsial bacteria
internal combustion: the combustion of fuel inside a cylinder (as in an internal-combustion engine)