How Mites Choose a Host and Why They Chose You.
Having a family member or friend with parasitic mites can be confusing. The affected person claims to be infested, yet the mites are not visible and there are often no physical signs. Here are some questions and answers that may help.
If she/he has mites, why can’t you see them? Why don’t we have specimens?
Bird mites are notoriously hard to catch. They are the size of the point of a pin, translucent, and quick moving. The glue traps used for mites don’t have pheromones, like moth traps do, so they don’t attract mites. Mites respond strongly to pheromones, so it would be a big improvement if mite traps were baited with pheromones.
Researchers working with scavenger face mites (which we all have) developed a way of capturing mite DNA from human skin using strong glue. Then they sequence the DNA to find the species. If this method starts being used for parasitic mites, it will become easier to help people with bird mites.
If my family member has mites, why are there no bite marks?
When a mite ingests living blood, the blood mounts an immune response from inside the mite’s gut. When any parasite ingests blood, it leaves behind proteins in the host. Mites have evolved to leave behind a protein that suppresses the immune system of the host, so the mite won’t be attacked by its food. One effect of immunosuppression is that bite marks are less pronounced (or nonexistent) when a host has been bitten by mites for months.
If one family member has mites, why don’t other people in the family have them?
Agricultural bulletins advise farmers who think their flock may have mites to take several chickens to the veterinarian. This is because there is a big variation in the level of infestation of different individuals. The tendency to choose just one chicken is adaptive for mites, who cluster on one bird in a flock and bleed it to the point where it is a stationary meal.
There is no reason mites infesting a human family would behave differently than they do when they choose a favorite chicken.
My doctor/pesticide professional/farm club teacher says chicken mites don’t bite people, and/or can’t reproduce on human blood. Is that true?
An article published in a 1958 science journal documented finding human blood cells in mite intestines. The only way those cells got there is for “bird mites” to feed on human blood. It is surprising that misinformation about mites has persisted for decades.
Leading mite experts acknowledge that what we call “bird mites” can reproduce when they feed on human blood. These mites can adapt to a variety of species.
Our house has already been treated for mites. Why does my family member still claim to get bitten?
Farmers know how hard it is to get rid of mites in a chicken coop. Sometimes the only way is to burn it to the ground, and then treat the dirt where the coop stood. Treatment isn’t easy in a human home, either.
Mites rapidly evolve resistance to pesticides. In addition, mites can hide inside books, wood paneling, etc., during pest treatment. Pest control professionals realize there is no test to prove that a building no longer has mites. As a result, a pest control company typically will refuse to represent in writing that the mites in a treated building are gone. The most accurate way to check the effectiveness of pest control efforts is to treat a home and then see if a susceptible person is still bitten.
How do you get rid of mites and how long does it take?
The key to getting rid of mites is to kill them faster than they can reproduce. And because the host and the environment are co-infested, both must be addressed at the same time.
Killing mites involves:
- Frequent and thorough cleaning of the body and the dwelling
- Use of pyrethrins and other pesticides on the dwelling
Lowering mites’ reproductive rate involves:
- Using growth hormones on the dwelling that prevent sexual maturation of mites
- Eliminating mite hiding places (carpeting in home and car; clutter; long hair on the body)
- Maintaining a cool, dry environment (use of dehumidifiers in all rooms is recommended)
Every situation is different and there is no exact timeline. Having family support for the work involved can speed up the process.
Is there a diagnostic test for mites? How about a treatment?
Research is being conducted on a nucleic acid test that would indicate a current infestation, but the test is still in development.
As for a treatment: researchers are developing a poultry vaccine that would boost the ability of the bird’s immune system to combat parasitic mites. It would be possible to develop a similar vaccine for humans.
When chicken mites are diagnosed in a coop, the coop and the chickens are treated at the same time. Some doctors prescribe Ivermectin to people with chicken mites. Just as with chickens and chicken coop, ivermectin treatment of a person should be coordinated with treating the family home.
Mites are supposed to be ectoparasites that live outside the body. My family member claims mites bite her/him inside her/his nose and ears. How is that possible?
We call bird mites ectoparasites. But mites are attracted to warmth and moisture. And there is no dividing line stopping a mite from crawling into a body cavity.
Are mite infestations becoming more common?
There are several reasons why mite infestations may be increasingly common.
- Mites reproduce rapidly and are evolving resistance to pesticides.
- The popularity of backyard poultry raised by non-farmers who lack pest management skills may lead to more mites (and bed bugs) in our cities and towns.
- Global warming could also make it easier for these heat-loving organisms to spread.
What can our family do to help?
Keep an open mind. Your family member cannot prove she/he has mites, and you cannot prove she/he does not have mites. If your loved one does have an infestation, saying the person has a psychological problem will add to the heavy burden of getting rid of these vermin. Imagine being in their shoes.
Your family member may get lucky and capture a specimen tomorrow. Or they may never have that good fortune. Either way, this is a person you love and respect. Trust them to let you know the kind of help they need.