Itch Mite

• GeneralIt tunnels into the outer skin to lay its eggs, causing intense itching.
• The World Health Organization lists scabies among the neglected tropical diseases: it affects more than two hundred million people at any one time.
• The same species causes sarcoptic mange in foxes, wolves, wild canids and wombats, with outbreaks capable of decimating whole wildlife populations.
• The itching is not caused by the mite directly but by the host's immune response, which is why it takes weeks to appear in a first infestation.
• The female tunnels at half a millimetre to five millimetres a day throughout the four to eight weeks she lives, laying eggs along the way.
• Its saliva dissolves the outer layer of skin, which is how it makes headway and how it feeds, on the intercellular fluid that collects in the burrow.
• Away from a host it survives only two or three days, so transmission through clothing or towels is uncommon; skin-to-skin contact is the norm.
• A classic case of scabies involves barely ten to fifteen mites on the whole person. The itching is caused not by their number but by an allergic reaction to their droppings and saliva.
• Crusted scabies is the opposite: millions of mites on a single host, and it occurs in people who are immunosuppressed or unable to scratch.
• The WHO declared scabies a neglected tropical disease in 2017.

Skeleton type

Invertebrate - chitin exoskeleton (arachnid)

Habitat and environment

A parasite: the skin of people and other mammals

Gestation / incubation

The eggs hatch in two to five days and the larva reaches adulthood in about three weeks

Litter / clutch size

Two to four eggs a day, up to about 40 or 50 over a lifetime

Sources consulted: Wikipedia (es): Sarcoptes scabiei