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Cold Tolerance of House Dust Mites
Abstracts AB119
370
Cold Tolerance of House Dust Mites
372
Difference in Mite Survival in Blankets Washed in Top-Loading Vs. Front-Loading Washing Machines.
Larry G. Arlian, PhD, FAAAAI, Ciara R. Feichtner, DiAnn L. Vyszenski-Moher, MS, and Marjorie S. Morgan, PhD; Wright State University, Dayton, OH. RATIONALE: The house dust mite, Dermatophagoides farinae, is a nidicole that lives in the nests of birds and mammals including human dwellings. In temperate climates in their natural environments in animal nests, the mites are likely exposed to cold and freezing temperatures. Likewise, these mites have been found in packaged baking mixes that consumers may refrigerate for storage and mites may survive these conditions. These mites may be adapted to tolerate low or freezing temperatures like many insects are. Freezing articles such as stuffed toys and pillows is recommended for killing mites in these items. The cold and freezing tolerance of house dust mites has not been extensively investigated. We determined the cold tolerance of D. farinae and report their survival in various cold and freezing conditions. METHODS: Female D. farinae, with and without a cold acclimation period at 48C were subjected to -38/-48 and -108C temperatures for various durations. Female survival, egg production and larval emergence were determined at various times post-freezing. RESULTS: Many female mites survived up to 18 hours at -38/-48C. After returning to room temperature, many surviving females produced viable eggs from which larvae emerged. A few females survived -108C for 2 to 12 hours but none of them produced eggs. CONCLUSIONS: The results suggest that D. farinae can tolerate and survive refrigeration and some freezing conditions. Thus, refrigeration and freezing temperatures and their durations should be a consideration in controlling dust mites in stuffed toys, pillows and food.
Jeffrey D. Miller, MD, FAAAAI; Mission: Allergy, Inc., Hawleyville, CT. RATIONALE: Blankets are reservoirs of dust mites and mite allergens. Previous studies of the effect of hot- and cold-water washing on the removal of dust mites from blankets have used top-loading washing machines, in which the machine’s tub is filled with water, which remains while being agitated. Particularly with cold or warm-water washing, many mites die by drowning or are simply washed out of the substrate while still alive. In contrast, many newer washing machines are water-conserving front-loaders, in which the item is repeatedly wetted and spun, without it staying submerged in water. We studied whether the type of machine affects the number of mites removed. METHODS: Sections of polyester blankets were inoculated with dense cultures of D. pteronyssinus mites and then vacuumed. They were separated into unwashed controls or washed in a top-loading (Kenmore 80 Series) or a front-loading (Asko W6424) machine, in hot (125oF at faucet, 115oF in tub top-loading; 140oF front-loading) or cold water, or in cold water with a non-bleach oxidizer. After air-drying, the live mites remaining in each section were counted using the Heat Escape method. RESULTS: Hot-water washing reduced mean mite numbers by 78% (p5.03) in the top loader, and 90% (p5.01) in the front-loader. Cold-water washing reductions were 65% (p5.05) top-loader, but only 10% (p5.78) front-loader. Adding the non-bleach oxidizer to cold washes had no significant effect on surviving mite numbers in either machine. CONCLUSIONS: Front loading machines are less effective than top loading machines in their ability to wash mites out of blankets in cold water.
371
373
Preliminary Proof of House Dust Mite Distribution Capability in the Environmental Exposure Unit
Terry J. Walker, BA1, Lisa M. Steacy, BSc1, and Anne K. Ellis, MD, FAAAAI1,2; 1Allergy Research Unit, Kingston General Hospital, Kingston, ON, Canada, 2Department of Medicine, Queen’s University, Kingston, ON, Canada. RATIONALE: The Environmental Exposure Unit(EEU) is located in Kingston, Ontario, Canada and has historically conducted studies using seasonal allergens(pollen). The EEU has developed a sub-unit within the EEU that will specialize in the circulation of house dust mite(HDM). We aimed to demonstrate that HDM can be suspended in the unit over a period of time. METHODS: The HDM-EEU is a semi-permanent structure built within the main EEU and contains an anteroom for participant gowning as the HDM-EEU is a clean room facility. The HDM-EEU can seat approximately 50 participants and also allows for the presence of physicians/staff. HDM raw material(GreerÒ, NC, USA) was distributed into the seating area using laminar flow for 1.5hours and particle concentration was measured by four RotorodsÒ(sampling q30min) and a laser particle counter(LPC) at the same 4 locations. RESULTS: HDM was distributed throughout the HDM-EEU with an average particle concentration of 6543.97 particles/m3. RotorodÒ observations confirmed the presence of HDM bodies/material but RotorodÒ HDM identification was noted to be inconclusive, confirming the requirement for filter capture and ELISA measurement of major allergen content(Der p1, Der f1). CONCLUSIONS: This preliminary evaluation of the HDM-EEU has shown our dispersal equipment can distribute HDM allergen throughout the facility. The LPC and RotorodsÒ are not sufficient to provide the full picture of HDM exposure, only particle concentration. Since the HDMEEU is a clean room, LPC counted particles are known to be HDM, however, this is not sufficient for clinical trial purposes where the use of ELISA for accurate measurements will be used.
Relation Of Sensibilization Among 10 Mites In A Tropical City. Sensitization Patterns According To Allergic Diseases.
Julian E. Londono, MD1, Jorge M. Sanchez1,2, Andres Sanchez1,3, Victor D. Calvo1, Libia S. Diez1, and Ricardo Cardona1; 1Group of Clinical and Experimental Allergology, IPS University, University of Antioquia, Medellin, Colombia, 2Foundation for the Development of Medical and Biological Sciences (FUNDEMEB), Cartagena, Colombia, 3Institute for Immunological Research, University of Cartagena (Cartagena, Colombia)., Medellin, Colombia. RATIONALE: Mites are the main source of sensitization in the tropics and one of the leading causes of allergies in the world. Sensitization to 10 mites species at the city of Medellın in patients with asthma, rhinitis, dermatitis and conjunctivitis was investigated. METHODS: Cross-sectional study of a cohort with 147 patients to evaluate sensitization to 10 mites through skin tests (Blo t, Der f, Der p, Aca s, Cho, Der m, Eur m, Gly d, Lep d, Tyr p). A generalized linear model of Poisson regression with a robust error variance to adjust the prevalence ratio (PR) by age, sex and type of allergic disease was applied. RESULTS: Eighty-nine percent of the patients had rhinitis, 50.3% asthma, 48.3% conjunctivitis and 17% dermatitis. When evaluating the prevalence ratio of sensitization to Blo t, Der m, Eur m, Gly and Tyr p d compared to other mites, it was found that Der f and Der p had the highest adjusted PR (p <0.01). From patients with positive sensitization to Der f, Eur m and Gly d, all patients tested positive for sensitization to Der p. CONCLUSIONS: Sensitization to Dermatophagoides mites, increases the predicted probability of sensitivity to other mites.
SUNDAY
J ALLERGY CLIN IMMUNOL VOLUME 139, NUMBER 2
370
Cold Tolerance of House Dust Mites
372
Difference in Mite Survival in Blankets Washed in Top-Loading Vs. Front-Loading Washing Machines.
Larry G. Arlian, PhD, FAAAAI, Ciara R. Feichtner, DiAnn L. Vyszenski-Moher, MS, and Marjorie S. Morgan, PhD; Wright State University, Dayton, OH. RATIONALE: The house dust mite, Dermatophagoides farinae, is a nidicole that lives in the nests of birds and mammals including human dwellings. In temperate climates in their natural environments in animal nests, the mites are likely exposed to cold and freezing temperatures. Likewise, these mites have been found in packaged baking mixes that consumers may refrigerate for storage and mites may survive these conditions. These mites may be adapted to tolerate low or freezing temperatures like many insects are. Freezing articles such as stuffed toys and pillows is recommended for killing mites in these items. The cold and freezing tolerance of house dust mites has not been extensively investigated. We determined the cold tolerance of D. farinae and report their survival in various cold and freezing conditions. METHODS: Female D. farinae, with and without a cold acclimation period at 48C were subjected to -38/-48 and -108C temperatures for various durations. Female survival, egg production and larval emergence were determined at various times post-freezing. RESULTS: Many female mites survived up to 18 hours at -38/-48C. After returning to room temperature, many surviving females produced viable eggs from which larvae emerged. A few females survived -108C for 2 to 12 hours but none of them produced eggs. CONCLUSIONS: The results suggest that D. farinae can tolerate and survive refrigeration and some freezing conditions. Thus, refrigeration and freezing temperatures and their durations should be a consideration in controlling dust mites in stuffed toys, pillows and food.
Jeffrey D. Miller, MD, FAAAAI; Mission: Allergy, Inc., Hawleyville, CT. RATIONALE: Blankets are reservoirs of dust mites and mite allergens. Previous studies of the effect of hot- and cold-water washing on the removal of dust mites from blankets have used top-loading washing machines, in which the machine’s tub is filled with water, which remains while being agitated. Particularly with cold or warm-water washing, many mites die by drowning or are simply washed out of the substrate while still alive. In contrast, many newer washing machines are water-conserving front-loaders, in which the item is repeatedly wetted and spun, without it staying submerged in water. We studied whether the type of machine affects the number of mites removed. METHODS: Sections of polyester blankets were inoculated with dense cultures of D. pteronyssinus mites and then vacuumed. They were separated into unwashed controls or washed in a top-loading (Kenmore 80 Series) or a front-loading (Asko W6424) machine, in hot (125oF at faucet, 115oF in tub top-loading; 140oF front-loading) or cold water, or in cold water with a non-bleach oxidizer. After air-drying, the live mites remaining in each section were counted using the Heat Escape method. RESULTS: Hot-water washing reduced mean mite numbers by 78% (p5.03) in the top loader, and 90% (p5.01) in the front-loader. Cold-water washing reductions were 65% (p5.05) top-loader, but only 10% (p5.78) front-loader. Adding the non-bleach oxidizer to cold washes had no significant effect on surviving mite numbers in either machine. CONCLUSIONS: Front loading machines are less effective than top loading machines in their ability to wash mites out of blankets in cold water.
371
373
Preliminary Proof of House Dust Mite Distribution Capability in the Environmental Exposure Unit
Terry J. Walker, BA1, Lisa M. Steacy, BSc1, and Anne K. Ellis, MD, FAAAAI1,2; 1Allergy Research Unit, Kingston General Hospital, Kingston, ON, Canada, 2Department of Medicine, Queen’s University, Kingston, ON, Canada. RATIONALE: The Environmental Exposure Unit(EEU) is located in Kingston, Ontario, Canada and has historically conducted studies using seasonal allergens(pollen). The EEU has developed a sub-unit within the EEU that will specialize in the circulation of house dust mite(HDM). We aimed to demonstrate that HDM can be suspended in the unit over a period of time. METHODS: The HDM-EEU is a semi-permanent structure built within the main EEU and contains an anteroom for participant gowning as the HDM-EEU is a clean room facility. The HDM-EEU can seat approximately 50 participants and also allows for the presence of physicians/staff. HDM raw material(GreerÒ, NC, USA) was distributed into the seating area using laminar flow for 1.5hours and particle concentration was measured by four RotorodsÒ(sampling q30min) and a laser particle counter(LPC) at the same 4 locations. RESULTS: HDM was distributed throughout the HDM-EEU with an average particle concentration of 6543.97 particles/m3. RotorodÒ observations confirmed the presence of HDM bodies/material but RotorodÒ HDM identification was noted to be inconclusive, confirming the requirement for filter capture and ELISA measurement of major allergen content(Der p1, Der f1). CONCLUSIONS: This preliminary evaluation of the HDM-EEU has shown our dispersal equipment can distribute HDM allergen throughout the facility. The LPC and RotorodsÒ are not sufficient to provide the full picture of HDM exposure, only particle concentration. Since the HDMEEU is a clean room, LPC counted particles are known to be HDM, however, this is not sufficient for clinical trial purposes where the use of ELISA for accurate measurements will be used.
Relation Of Sensibilization Among 10 Mites In A Tropical City. Sensitization Patterns According To Allergic Diseases.
Julian E. Londono, MD1, Jorge M. Sanchez1,2, Andres Sanchez1,3, Victor D. Calvo1, Libia S. Diez1, and Ricardo Cardona1; 1Group of Clinical and Experimental Allergology, IPS University, University of Antioquia, Medellin, Colombia, 2Foundation for the Development of Medical and Biological Sciences (FUNDEMEB), Cartagena, Colombia, 3Institute for Immunological Research, University of Cartagena (Cartagena, Colombia)., Medellin, Colombia. RATIONALE: Mites are the main source of sensitization in the tropics and one of the leading causes of allergies in the world. Sensitization to 10 mites species at the city of Medellın in patients with asthma, rhinitis, dermatitis and conjunctivitis was investigated. METHODS: Cross-sectional study of a cohort with 147 patients to evaluate sensitization to 10 mites through skin tests (Blo t, Der f, Der p, Aca s, Cho, Der m, Eur m, Gly d, Lep d, Tyr p). A generalized linear model of Poisson regression with a robust error variance to adjust the prevalence ratio (PR) by age, sex and type of allergic disease was applied. RESULTS: Eighty-nine percent of the patients had rhinitis, 50.3% asthma, 48.3% conjunctivitis and 17% dermatitis. When evaluating the prevalence ratio of sensitization to Blo t, Der m, Eur m, Gly and Tyr p d compared to other mites, it was found that Der f and Der p had the highest adjusted PR (p <0.01). From patients with positive sensitization to Der f, Eur m and Gly d, all patients tested positive for sensitization to Der p. CONCLUSIONS: Sensitization to Dermatophagoides mites, increases the predicted probability of sensitivity to other mites.
SUNDAY
J ALLERGY CLIN IMMUNOL VOLUME 139, NUMBER 2