Rat Mites? Well, Now You Know

A rat mite shot through the lens of the author’s microscope with a cat hair to show scale. The mite is red because it’s full of blood. Yuck. Whatever you do to get rid of them, do not use rodenticides. Photo by Suzanne Guldimann

The tropical rat mite is almost too small to be seen, but can inflict an astonishing amount of pain and misery.

This nearly microscopic member of the tick and spider family is neither tropical nor exclusive to rodents. Although rats are its preferred host, any mammal can provide a meal for this rapacious pest. Despite the fact that Ornithonyssus bacoti is reportedly one of the most common house-invading species, there is surprisingly little information about it.

A New York Magazine article by Jessica Roy from 2014 describes them as being worse than bedbugs. “Why are rat mites so much more disgusting than bedbugs?” she wrote. “Because they come from RATS. Do I even need to explain how disgusting rats are?”

Residents of the Santa Monica Mountains don’t have to deal with New York City rats, but they may have an elevated risk of encountering tropical rat mites this year. The wet winter and abundant food has resulted in a bumper crop of rodents, increasing the odds that rat mites are also abundant this season.

Common rat mite hosts include the tree rat and the native dusky-footed woodrat, or pack rat. O. bacoti reportedly must feed on rat blood in order to reproduce but that doesn’t stop it from snacking on the nearest mammal, if its rat host dies or abandons its nest.

According Los Angeles County Vector Control, “mites can become serious pests when there are many rats living within the structure, but most often they make their presence known shortly after control measures are started to eliminate the rats (the primary host). When trapped or poisoned rats die or fail to return to the nest, the mites migrate into the living areas of the structure to feed on human or animal hosts.”

Unfortunately for humans, the mites are attracted to carbon dioxide and heat and can travel long distances at a remarkably rapid rate for something so small.

Vector Control reports that “the mites are ultimately drawn to those areas within the home which experience the greatest amount of human activity. Rooms such as kitchens, family rooms, bedrooms and work areas maintain the highest concentrations of carbon dioxide and are highly attractive to the mites. Mites are also attracted to frequently used furniture such as sofas, recliners and beds, and will bite the occupants as they rest or sleep.”

Two other related mite species also occasionally cause problems for humans and pets: O. bursa, the tropical fowl mite; and O. sylviarum, the northern fowl mite. Both of these species are associated with both domestic and wild birds but can also be found in homes, attracted by wild birds nesting around the house or by a backyard chicken coop.

Bites of all three species can reportedly be painful, even if the biter is too small to be seen, and can result in an itchy dermatitis and mosquito bite-like welts. Cats and dogs may be hardest hit by an infestation. In particular, rat mites seem to seek out cats. Symptoms may include fur loss and a red rash on the belly or tail area.

Although there are topical treatments for the skin irritation for humans and animals, and many vets prescribe systemic anti-mite medications for infested pets, research indicates that the only effective way of eliminating an infestation is getting rid of the rodents and their nesting material, and making sure future rodents are excluded from the home by sealing entrances like gaps around pipes and vents. Do not use rodenticides!

Vector Control also points out  that “trapping or otherwise killing rats may increase the activity of the mites as they search for other hosts,” leaving victims in a quandary. Mites are sometimes visible when they are on the move. A fine-toothed comb can be used to remove them from pets. For humans, bites can be treated with Cortizone cream, lidocaine sprays, or calamine lotion. A vet should be consulted when pets are affected.

 Frequent vacuuming, dusting and washing may help control mites. Some mite survivors swear by diatomaceous earth, others by spraying vinegar or rubbing alcohol on bedding and hard surfaces, others claim nothing works. Sometimes the victims simply have to wait out the infestation, once the rats are eliminated and excluded. 

Vector Control points out that the mites do not burrow beneath the skin, and that they are “easily removed by bathing or showering.” They are not known to transmit any disease, and since neither rat mites nor bird mites can reproduce in the absence of their primary host, they will eventually die out; all of which may be a least a small comfort to anyone coping with a full-scale invasion.

More information on tropical rat mites and their fowl (and foul) relations can be found at: www.publichealth.lacounty.gov.


Suzanne Guldimann

Suzanne Guldimann is an author, artist, and musician who lives in Malibu and loves the Santa Monica Mountains. She has worked as a journalist reporting on local news and issues for more than a decade, and is the author of nine books of music for the harp. Suzanne's newest book, "Life in Malibu", explores local history and nature. She can be reached at suzanne@messengermountainnews.com

  1. I had a mom and babies in my home, when I called the pest control, they put out poison, needless to say they died in the furniture. This was last March. We still have the mites in our home and on our bodies. I’ve tried everything and nothing seems to kills these monsters. Can you tell me what to do I am in desperate need of help.
    Thank you

  2. They do burrow under the skin and they do reproduce. I’ve had them for almost 1 year and nothing helps if you know something I don’t please share it with me. Thank you

  3. Hi Debra, I would recommend reaching out to the nearest university or agricultural office to see if they can provide guidance. Rat mites need their specific host to reproduce. If they are the culprits then there are more rats nearby, but it could be bird mites or even scabbies mites. Unfortunately there are a lot of lesser known parasites out there that can inflict misery on humans even when we aren’t their primary host. If it is any consolation, non of these mites burrow into the skin, it just feels like they do. Good luck. I hope your troubles are over soon.

  4. Oh yes they DO transmit disease!
    Many zoonotic diseases in fact.
    Lyme disease is just one of many, even emerging coronavirus
    Is transmitted by rodent mites.
    You cannot write a blog and say rat mites are
    Far from it, in fact they led to my hubby dying young
    Age just 43 ! Rat mites caused his immune system to
    Drop out and worsened his lung issues very very badly.

    They also send you to the point of suicidal when they infest
    Your home badly It’s hell , they are evil and get in your clothes,
    Beds, books cds warm electrical equipment. Everything.
    Pure hell.
    Very hard to kill too.
    It’s no fun having a rat mite infestation and can be very serious
    In many ways.
    The rest of the blog and info is interesting but it needs updating
    To include zoonotic diseases.
    Thanks kindly.

    1. Gina, have you been able to find a solution to get rid of these hellacious mites? I have not after more than 3.5 years of misery! I’ve spent so much money, moving, switching jobs (because I end up transferring them to my work areas). I believe they imprint on a specific person’s (DNA) as well as use carbon dioxide and heat to find us. I know in cases of chickens with bird mites, they typically attack one hen. I have documented photographs of all the bites; they target my nose and buttocks. I was told those areas have the highest hormone concentrations. I clean daily, ceilings, walls, floors. Work areas and car as well, steam and vacuum.

      Have bought and used the following to no avail:
      1) ozone generator
      2) Dr. Ben’s Evictor (Cedar) and a fogging machine (both very expensive and did NOT work)
      3) 2 PCO’s (professional pest control)
      4) essential oils
      5) garlic sprays
      6) Premoguard
      7) enzyme cleaners
      8) borax
      9) DE
      10) went to a naturopath, took many herbal supplements
      11) dermatologists are ignorant of this, they did painful punch tests on my skin/to deep dermal layers only to confirm I had been bitten by a arthropods, but they couldn’t help me
      12) used Permethrin cream (works for about 8 hours only)
      13) Ivermectin (works for 3 days only)
      14) rubbing alcohol
      15) DIY Suspend SC
      16) Onslaught with Nyguard additive, growth inhibitor)
      17) coconut oil
      18) tape
      19) wrap everything in plastic
      20) live with minimal belongings
      21) Epsom salts in shower
      22) shower twice daily
      23) children’s lice repelling natural shampoo

      I do get a short respite on areas covered with cornstarch and baking soda (but it dries out skin painfully/changes ph).

      Any solutions?

  5. I hate to burst the bubble of the author and dozens of pest control companies out there but telling people that tropical rat mites cannot live or reproduce without a rat to feed on is entirely false and harmful. I know from 3rd, 2nd, and 1st hand experience. My mom had a rat infestation in her attic, 6.5, yes I repeat 6.5 years ago, and is still living with the mites to this day 2 MOVES later. She has not had rats or mice in 6 years, her dog died 5 years ago, just one pet-less old person and the mites continue to endure.

    They are not scabbies, or bed bugs or bird mites. They. Are. Rat. Mites. They go after her where she sleeps (being attracted to CO2), they bite, they are fast. Not only can they do just fine surviving on human blood, they flourish on it, can endure for GENERATIONS and get much much worse and more active in the summer or if using space heaters.

    Another site claiming they won’t hitch-hike or spread to other locations is also entirely unfounded and wrong. After years of being incredibly careful when visiting her and like I said ((2 whole moves since her original infested property)) my boyfriend and I now have them at our place. I also had a relative who several years ago had a mite infestation at her business. You can bet it took no time at all til they were in her home. It took her moving with only a few of her belongings to one of the coldest states in the U.S. before she was free of them. After a nearly 5 YEAR STRUGGLE.

    They love munching on women, in our hair and private areas ESPECIALLY if menstruating. They absolutely can stay on furniture and clothes and move with you to other locations so it’s important to be incredibly thoughtful and thorough about where and what is exposed. None of you are crazy, overreacting, or imagining things. If you think you still have them it’s because you do.

    These critters are FAR more durable and insatiable than have been reported. Maybe some are fortunate enough to only deal with them a few weeks. Not anyone I know. I’ve been pulling out all the stops the past 2 weeks. Removed all throw and area rugs, soaked the wood floors in 70-99% alcohol multiple times. Washed and dried the linens every day and any clothes that touch our body, the bed, or floor. Wrapped the bed in double plastic. Gotten all furniture up off the floor. They. Are. Still. Here.

  6. I’ve had an infestation of rat mites for more than 3.5 years. It began when I found a dead rat in my backyard in Pasadena. I haven’t been able to get rid of them and have moved now 3 times, and switched jobs 3 times because of this! I am bitten daily by these microscopic mites; they feel like painful pinpricks, and have the bites as proof. The bites are typically in a linear or triangular pattern, a dermatologist called it “breakfast, lunch, and dinner.” They do multiply from human blood; the belief that they do not is misinformation.

    I clean daily, ceilings, walls, floors, steam and vacuum. Sealed all the crevices I could find, had 3 pesticide companies spray monthly, used DE, an ozone generator, Sterifab, vinegar, tea tree oil, Dr. Ben’s Evictor, cedar oil, essential oils, Onslaught, Suspend SC, enzyme cleaners, rubbing alcohol, borax, Premoguard, many more products that have been recommended but nothing has worked and no one can help. Most dermatologists are ignorant about this topic. I’ve contacted top entomologists at universities in England, Spain, the US and no one has any answers for me. Thousands of people globally are suffering with similar infestations and have no help.

    This has to be the worst nightmare of my life!

  7. We’ve found over many years of dealing with these pests here in Topanga that if you can set the snap trap in a bed of diatomaceous earth that the fleeing mites die in this substance.

    Eric Fitzgerald

  8. I have an infestation of mice in the building I live in and my apartment. It’s a really old house. We have been getting these random bites on our ankles a lot and then also other places randomly too. We haven’t been able to figure out what it was and we have been washing and changing the sheets like every two days. We just found one of these on the cap of a water bottle. I took a picture with a magnifying glass and did an image search and this is exactly what it is 100%. I don’t know what to do and my landlord is doing nothing about the mice infestation. Please help! Thank you!

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