S.16/E.15

This week we will discuss Ectoparasites.  The CDC says: "Although the term ectoparasites can broadly include blood-sucking arthropods such as mosquitoes (because they are dependent on a blood meal from a human host for their survival), this term is generally used more narrowly to refer to organisms such as ticks, fleas, lice, and mites that attach or burrow into the skin and remain there for relatively long periods of time (e.g., weeks to months). Arthropods are important in causing diseases in their own right, but are even more important as vectors, or transmitters, of many different pathogens that in turn cause tremendous morbidity and mortality from the diseases they cause.

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An ectoparasite is a parasite that lives on the outside (exterior) of its host. They’re vectors (living things that carry diseases between animals and humans) that usually carry infections through blood. Many creatures that healthcare providers classify as vectors feed on your blood. They generally include:

• Fleas. Fleas are small, wingless insects with strong back legs that they use to jump long distances. Infected fleas can spread disease when they bite their host or if a host accidentally swallows an infected flea.

• Head lice and pubic lice (crabs). Lice are tiny, flat insects that travel by crawling. Head lice live on the hair on your head. Pubic lice live in your pubic hair, near your genitals. Both types of lice travel from person to person through close contact, which may include sexual intercourse or sharing personal items like sheets, pillows or towels.

• Mites. Mites are small arachnids (eight-legged arthropods) that are relatives of spiders and ticks. They’re smaller than 1 millimeter (0.04 inches, about as tall as a stack of 10 sheets of paper). Certain types may cause scabies.

• Ticks. Ticks are arachnids. Their bites usually don’t cause pain or itchiness. They typically bite you and then burrow into your skin. They’re common in wooded areas or grassy fields.