Insecticidal sprays and fumigants capable of killing human lice are dangerous to pets and humans because they can be absorbed through the skin. The U.S. Centers for Disease Control and Prevention does not recommend their use to control lice and do not recommend any lice treatments for pets.
Head lice can live and reproduce only on a human host. When separated from humans, adult lice live only 48 hours, and eggs die within a week. This makes treating infested people the most important step in controlling lice. Pets cannot transmit lice, and only items that have been in contact with the head or neck of an infested person within 48 hours need cleaning.