Indoor Dust Mite Fecal Pellets
This is a tapelift of a dark deposit on the underside of plywood roofing collected in the attic of a home in western Washington State. There is a common sequence in the attic flora and fauna of the marine Northwest. First mold growth from condensation, then mites grazing on the mold, then preditors eating the mites, and finally, summer heat that kills them all or drives them to other parts of the attic space or home.
Transmitted Off Crossed Circular Polarized Light Illumination
Mites or their debris are found in indoor environments frequently. They all tend to be small ranging from about 40 micrometers to about a millimeter in largest dimension. They lay eggs and then develop through a number of intermediate stages. The adult mite has 8 legs but the intermediate stages may have 2 to 8 legs, depending on the species and the stage. All mites require a relative humidity above 50% but they will often occupy cooler parts of a home where the relative humidity is naturally higher. They will also inhabit bedding and clothing where the relative humdity is elevated due to the presence of the human body. Their prefered food varies by species. Many of them will survive on skin flakes.
Armentia, Alicia, Manuel Lombardero, Camilo Martinez, Domingo Barber, Jose Maria Vega, Ana Callejo, “Occupational Asthma Due to Grain Pests Eurygaster and Ephestia” Journal of Asthma, Volume 41, Number 1, 2004, pp. 99-107(9)
Boese, Jack L., “Mites”, in PRINCIPLES OF FOOD ANALYSIS FOR FILTH, DECOMPOSITION, AND FOREIGN MATTER, ed. J. Richard Gorham, pp. 63-82, 1985
Bronswijk, J.E.M.H. and R. N. Sinha, Pyroglyphid mites (Acari) and house dust allergy, J Allergy, 1971;47:31-49.
Colloff, M.J., T.G. Merrett, J. Merrett, C. McSharry, and G. Boyd, Feather mites are potentially an important source of allergens for pigeon and bungerigar keepers, Clinical and Experimental Allergy, 1997;27:60-7.
Hallas, T.E. and J. Korsgaard, "Systematic variations in the appearance of house-dust mites (Dermatophagoides spp.), house mites (Glycyphagus domesticus), and of Tarsonemus sp. in dust samples from dwellings", REV. ESP. ALERGOL INMUNOL CLIN, vol. 12, no. 4, pp. 173-177, June 1997. available on line at http://revista.sealc.es/junio97/173-178.pdf
Hughes, A.M., THE MITES OF STORED FOOD, Ministry of Agriculture, Fisheries, and Food, Technical Bulletin No. 9, 1961.
Oliver, Jean, Karen Biringham, Angela Crewes, Jenny Weeks, Fleming Carswell, "Allergen levels in airborne and surface dust". INT. ARCH. ALLERGY IMMUNOL, vol. 107, pp 452-453, 1995.
Olsen, Alan R. and Richard W. Potter, “Mites”, in FUNDAMENTALS OF MICROANALYTICAL ENTOMOLOGY, by Alan R. Olsen, Thomas H. Sidebottom, and Sherry A. Knight, CRC Press, pp. 123-134, 1996.
Olsson, S. and M. Van Hage-Hamsten, “Allergens from house dust and storage mites: similarities and differences, with emphasis on the storage mite Lepidoglyphus destructor”, Clinical and Experimental Allergy, vol. 30, pp 912-919, 2000.
Ryu, Jae-Sook, Han-Il Ree, Duk-Young Min, and Myoung-Hee Ahn, “A human case of house dust mite Tarsonemus floricolus collected from sputum”, The Korean Journal of Parasitology, vol. 41, No. 3, pp. 171-173, Sept. 2003.
Silton, Richard P., Enrique Fernandez-Caldas, Walter L. Trudeau, Mark C. Swanson, and Richard F. Lockey, “Prevalence of specific IgE to the storage mite, Aleuroglyphus ovatus”, J. Allergy Clin. Immunol., pp. 595-603, Oct. 1991.
Tovey, E.R., Ajsa Mahmic, and Lindy G. McDonald, Clothing--an important source of mite allergen exposure, J Allergy Clin Immunol, 1995;96:999-1001
Wraith, C.G., A. M. Cunnington, and W.M. Seymour, Th role and allergenic importance of storage mites in house dust and other environments, Clinical Allergy, 1979;9:545-61.
Definition/Function:
Dust mite and many other mite fecal pellets (mite frass) are rounded elipsoids containing birefringent nitrogen containing chemical crystals (bright patches in the pellets). These may be found in tapelifts or surface dust samples. Fragments of these particles may be found in air samples. These particles also contain the allergen for the mites. The main nitrogen containing compound is guanine.Mites or their debris are found in indoor environments frequently. They all tend to be small ranging from about 40 micrometers to about a millimeter in largest dimension. They lay eggs and then develop through a number of intermediate stages. The adult mite has 8 legs but the intermediate stages may have 2 to 8 legs, depending on the species and the stage. All mites require a relative humidity above 50% but they will often occupy cooler parts of a home where the relative humidity is naturally higher. They will also inhabit bedding and clothing where the relative humdity is elevated due to the presence of the human body. Their prefered food varies by species. Many of them will survive on skin flakes.
Significance in the Environment:
There are over 124 different types of mites found in homes. Most of these are associated with allergies or asthma. The standard tests for mite allergen can only detect 2 of the 124 mites that may be present. The collection efficiency of a vacuum for even the 2 mites that could be detected is estimated at about 1%. Minor flucuation in that efficiency result in variations of a factor of 20X (2000%). Part of this variation is due to the fact that the mite allergen is often concentrated in a few large particles. The allergen of a few fragments would be swamped by the allergen associated with one whole mite. Tapelifts of settled dusts in homes have been much more consistent in detecting mite problems.Characteristic Features:
These particles tend to be round to oval in shape and contain numerous birefringent crystals of guanine.Associated Particles:
Generally some mite fragments can be found in samples containing significant numbers of these particles.References:
Arlian, Larry G., DiAnn L. Vyszenski-Moher, S. G. O Johansson, and Marianne van Hage-Hamsten, “Allergenic characterization of Tyrophagus putrescentiae using sera from occupationally exposed farmers”, Annals of Allergy, Asthma, & Immunology, vol. 79, pp. 525-529, Dec. 1997.Armentia, Alicia, Manuel Lombardero, Camilo Martinez, Domingo Barber, Jose Maria Vega, Ana Callejo, “Occupational Asthma Due to Grain Pests Eurygaster and Ephestia” Journal of Asthma, Volume 41, Number 1, 2004, pp. 99-107(9)
Boese, Jack L., “Mites”, in PRINCIPLES OF FOOD ANALYSIS FOR FILTH, DECOMPOSITION, AND FOREIGN MATTER, ed. J. Richard Gorham, pp. 63-82, 1985
Bronswijk, J.E.M.H. and R. N. Sinha, Pyroglyphid mites (Acari) and house dust allergy, J Allergy, 1971;47:31-49.
Colloff, M.J., T.G. Merrett, J. Merrett, C. McSharry, and G. Boyd, Feather mites are potentially an important source of allergens for pigeon and bungerigar keepers, Clinical and Experimental Allergy, 1997;27:60-7.
Hallas, T.E. and J. Korsgaard, "Systematic variations in the appearance of house-dust mites (Dermatophagoides spp.), house mites (Glycyphagus domesticus), and of Tarsonemus sp. in dust samples from dwellings", REV. ESP. ALERGOL INMUNOL CLIN, vol. 12, no. 4, pp. 173-177, June 1997. available on line at http://revista.sealc.es/junio97/173-178.pdf
Hughes, A.M., THE MITES OF STORED FOOD, Ministry of Agriculture, Fisheries, and Food, Technical Bulletin No. 9, 1961.
Oliver, Jean, Karen Biringham, Angela Crewes, Jenny Weeks, Fleming Carswell, "Allergen levels in airborne and surface dust". INT. ARCH. ALLERGY IMMUNOL, vol. 107, pp 452-453, 1995.
Olsen, Alan R. and Richard W. Potter, “Mites”, in FUNDAMENTALS OF MICROANALYTICAL ENTOMOLOGY, by Alan R. Olsen, Thomas H. Sidebottom, and Sherry A. Knight, CRC Press, pp. 123-134, 1996.
Olsson, S. and M. Van Hage-Hamsten, “Allergens from house dust and storage mites: similarities and differences, with emphasis on the storage mite Lepidoglyphus destructor”, Clinical and Experimental Allergy, vol. 30, pp 912-919, 2000.
Ryu, Jae-Sook, Han-Il Ree, Duk-Young Min, and Myoung-Hee Ahn, “A human case of house dust mite Tarsonemus floricolus collected from sputum”, The Korean Journal of Parasitology, vol. 41, No. 3, pp. 171-173, Sept. 2003.
Silton, Richard P., Enrique Fernandez-Caldas, Walter L. Trudeau, Mark C. Swanson, and Richard F. Lockey, “Prevalence of specific IgE to the storage mite, Aleuroglyphus ovatus”, J. Allergy Clin. Immunol., pp. 595-603, Oct. 1991.
Tovey, E.R., Ajsa Mahmic, and Lindy G. McDonald, Clothing--an important source of mite allergen exposure, J Allergy Clin Immunol, 1995;96:999-1001
Wraith, C.G., A. M. Cunnington, and W.M. Seymour, Th role and allergenic importance of storage mites in house dust and other environments, Clinical Allergy, 1979;9:545-61.
