Tropical Rat Mite


Actual Size: Up to 1 mm when engorged

Characteristics: A tiny mite with a few short hairs on the body, which is a light tan to orange color before feeding and a darker color post-feeding.


  • One of the most common house invading mite species.
  • Most commonly found as a parasite on rats.
  • Their bite can be painful and cause irritation or itching.


The tropical rat mite can be extremely annoying, but whether it can transmit human diseases is unclear. The primary host of the tropical rat mite is the roof rat, and because of its association with this commensal rodent, the mite is now distributed worldwide. More often seen in warmer regions of the world, these mites infest used or abandoned rat nests. Tropical rat mites are very small, but visible to the naked eye. These mites are equal in size to a period at the end of a sentence. Mites are red if they have obtained a blood meal, and if unfed, are cream-colored. When engorged, females are about 1/25th inch long (1mm).


The life cycle of the tropical rat mite includes 5 developmental stages: egg, larva, protonymph, deutonymph, and adult. The adult mite emerges from the second nymphal stage at 68 -72 F, mates, and engorges within three days.  Larvae feed and drop from the host within two days, molting to the second nymphal stage in one more day. The entire life cycle takes as little as 11–13 days under optimum environmental conditions; however, protonymphs can survive for 43 days and adults for up 63 days without a blood meal. Female mites reach a size between 0.75 and 1.40 mm, males are a little smaller.


Tropical rat mites often become a serious problem where rat eradication programs are underway, for then they must attack humans and other animals to survive. Additionally, this mite is known to attack people, even when rats are abundant. Tropical rat mites are sometimes found in stores, restaurants, theatres, and other buildings. The mites usually feed at night or in semi-darkness and retreat to cracks, crevices, and other dark places until their next meal. These mites tend to accumulate in walls, particularly where there is a source of heat. For this reason, they will often be found near various heat sources such as hot water pipes, stoves, etc. Tropical rat mites bites may produce irritation and sometimes painful dermatitis that continues for two or three days. Itching, often severe, is a principal complaint. Both the nymphs and adults may attack humans, but the nymphs appear to be the most troublesome.


The most effective way to avoid tropical rat mites is to control their host, the roof rat. Exclusion, reduction, and elimination of rats are major components to successfully control this mite. Mites will only survive two to three weeks without a host. Below are common myths and suggestions to protect yourself and your home from tropical rat mites:


Contrary to false information available on the internet, rat mites are not the bane of human health. Of course, they can bite if people are exposed to them, but the effects are only temporary. Here are some facts about these tiny creatures:

  1. Rat mites will bite people, but cannot “infest” humans or start living on them.
  2. Rat mites cannot be transmitted from human to human.
  3. If rat mites get on a person, it’s temporary and will only occur on the outside of the body.
  4. Rat mites cannot survive without a rodent host present.
  5. Rat mites do not infest automobiles.
  6. Rat mites are usually not involved in human disease transmission.


The following prevention tips can help to reduce problems with tropical rat mites by preventing a roof rat infestation:

  • Make sure that garbage is placed in outdoor trash containers that have locking lids on them.
  • Store trash containers a distance away from the outside of your property.
  • Place woodpiles a distance away from the outside of your home.
  • Seal gaps in the foundation and place door sweep on exterior doors.
  • Place secure screens over the dryer and other vents.
  • Place items like bird feeders away from the exterior of your home.
  • Pick up uneaten pet food and store dry pet food in plastic containers with tight-fitting lids.
  • Keep food found inside of your home or business in sealed containers or the refrigerator and not out in the open on counters or tables.
  • If mites are found, thorough vacuuming is effective in eliminating some mites and their eggs. Dispose of vacuum bag after use.

If you have tried all the above measures and still experience tropical rat mite issues, It is best to consult a licensed pest control operator for interior pesticide treatments.