Ectoparasites

Ectoparasites are those parasites which remain external to, or in the surface layers of skin of the human body. They may cause pathology due to reaction against the parasite by the host immune system, destruction of tissue, or the introduction of another pathogenic agent by their feeding.

Ectoparasites include: insects such as Pediculus humanus capitis (head lice) and insect larvae such as Dermatobia hominis (human botfly); arachnids such as mites including Sarcoptes scabiei (causative agent of scabies) and ticks such as those from the family Ixodidae. Please note this is not an exhaustive list.

Diagnosis of Ectoparasites by microscopy

Sample types may include:

• The putative parasite itself in a small sealed container. This may be embedded in host tissue where the parasite has been surgically removed, such as occurs with Tunga penetrans (Jigger flea)
• Eggs attached to hair (eg. head lice) in a small sealed container
• Scrapings of skin from the location of a putative parasitic infection (eg. scabies). For skin scraping, ideally the sample should be scraped onto a black dermapak before transport

Samples may be referred on to the London School of Hygiene and Tropical Medicine for further analysis.