While the bird or mammalian hosts are present, the majority of the mites will remain close to the nest or roost sites so they may partake in a meal at most any time. A few mites may stray and enter a building through ventilation openings, air conditioners, windows (the mites are tiny enough to crawl through the openings in intact window screens), cracks, holes and any other wall penetration. If the normal hosts are displaced, excluded, fledge or die, then the mites left behind increasingly develop a wanderlust to satisfy their growing hunger. In such cases, hundreds – or many thousands – of hungry mites may enter a home or office. They may be so numerous as to resemble a diffuse mass of pepper grains on the walls and ceilings, with the exception that these grains are wandering about. Persons and pets living or working in such a dwelling may then experience a few – or considerable – bites by these mites.
Because the bird and rodent hosts are pests, they are often focus of pest control efforts. Successful reductions to the abundance of those hosts, however, may actually precipitate a marked increase in sightings of, and biting by, these mites. For this reason, pest control interventions should carefully consider the potential of biting mites on the hosts and within the dwelling. If mites are observed on indoor walls and ceilings, they should be sampled and examined microscopically by an expert to ascertain their identity. This will help inform residents, building owners / managers, clinicians and public health practitioners, and pest control operators. Non-baited insect glue traps can be helpful in collecting and retaining mites for identification. IdentifyUS provides such rapid, independent, confidential and expert evaluations.
If biting mites are detected or anticipated, the pest control efforts should include parallel and nearly simultaneous anti-rodent (or bird) and anti-mite procedures. These steps might include trapping / baiting / exclusion of hosts, removal and cleaning of roosting/nesting areas, and applications of acaricides (pesticides), as appropriate. Eliminating the hosts, without abating the mites, risks creating a dramatically worsening situation.
Mite of genus Dermanyssus, common ectoparasite of birds