Chiggers

Just come home after camping? Hope you haven’t got any itchy red spots on your legs. If you do, then you have just been visited by your friendly neighborhood chiggers. Although these little critters aren’t spiders, they are related to them. Chiggers (also known as the the harvest mites or red bugs or berry bugs or the scrub mites) are the juvenile (or larval) form of a specific family of mites, the Trombiculidae.

There are many myths regarding chiggers. The biggest myth is that the chiggers burrow deep in the skin like scabies mites which is not at all true. The chiggers are too big to enter the skin pore. Both the chiggers and scabies are very tiny in size, but the scabies mites are around 0.3 to 0.9 mm while the chiggers are less than 1/50th of an inch in diameter.

The scabies mites are almost transparent or greyish in colour. Chiggers however are born red. An engorged, well-fed chigger changes to a yellow color.

If chiggers do not burrow under skin like scabies or drink blood, what are they doing that makes us itch so much? They pierce the skin with their mouthparts and inject a digestive enzyme. The chigger’s piercing mouth parts are short and delicate, and can penetrate only thin skin or where the skin wrinkles and folds.

The injected enzymes literally dissolve the tissues they come in contact with. It is this liquified tissue that the chiggers feed on and not blood.  Within a few hours, tissue around the feeding area solidifies into a hardened tube, called a stylostome. The chigger sucks up liquefied tissue- like we drink a milkshake with a straw! The dissolved tissue will continue to ooze out of the wound each time it is scratched.

The fluid that oozes from the wound solidifies into a hard “cap.” This “cap” is a distinct feature of chigger bites and is not associated with other arthropod bites such as mosquitoes. This is very different from the Scabies sores which appear like red lesions on the skin.

Humans are only accidental hosts for the chiggers unlike scabies which prey on the humans with low immunity like the aged or diseased people.
More than 700 species exist worldwide, but only 20 cause dermatitis or vector diseases.The chiggers are less problematic than the scabies. The North American genus and species can cause severe illness in children when the infestation is heavy.

Symptoms include a hallucinatory sense of floating outside one’s body, fatigue, fever and general malaise. The chiggers appear as small red bumps across the skin unlike the zig zag or S patterns seen because of the scabies. However a scabies infestation is difficult to detect.

A person with scabies is highly contagious and can spread the disesase to anyone he might have been in contact with. Chiggers are known for not being able to spread host to host.

Both scabies and chiggers can be avoided by taking the proper preventive measures. The first basic step to avoid chiggers is using proper clothing when entering chigger infested habitats. Sulphur or a hot bath is another way to get rid of chiggers.