It has been known for head lice and other skin parasites to be passed on through contact with aircraft seats where previous passengers have been infested. However, this is a rare occurrence, as most airlines carry out thorough cleaning of the cabin and other facilities between flights.
International flights to the UK require the spraying of the aircraft passenger compartment with insecticide when travelling from designated countries in which there is a risk of a disease being spread by insects, such as malaria and dengue fever.
This process is called disinsection, and is carried out whilst while the passengers are present, in case an insect has been transported on clothing or in baggage. Flights into the UK that undergo disinsection include those from Mexico City, Cairo, Harare, Mumbai, Cape Town and Bangkok. Flights from the UK to cities such as Beijing, Delhi and Bangalore are also sprayed for insects and other parasites.