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House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
House dust mites & cockroach biology & avoidance
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House dust mites & cockroach biology & avoidance

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House dust mites & cockroach biology & avoidance …

House dust mites & cockroach biology & avoidance
Presented by Suparat Sirivimonpan, MD
February22, 2013

Published in: Health & Medicine
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  • 1. D u s t mi t e a n d Co c k r o a c h : Bi o l o g y a n d Av o i d a n c e Supa r a t S i r i v i mo n p a n , M D .
  • 2. CONTENTS• Introduction• Dust mite – Biology – Avoidance measures• Cockroach – Biology – Avoidance measures• Conclusions
  • 3. Introduction• The average child or adult spends at least 23 h/day indoors, at home, in a school, or at work , little time outdoors• This pattern has consequences for many chronic diseases but has special significance for allergic disease• The only diseases that have been associated statistically with exposure to dust mite or the other indoor allergens are chronic rhinitis, asthma, and atopic dermatitis• Rarely, cases of conjunctivitis, urticaria, and even anaphylaxis are associated with dust mite sensitization Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 4. Introduction• In addition, because of the length of time spent indoors, cumulative allergen exposure inside may be more important than outdoor exposure Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 5. Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 6. • - -House Dust : complex mixture of everything found in home -Variable quantities of many allergen - Monoclonal antibody assays capable of measuring individual allergens in the complex mix present in homes Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 7. Dust mite• Biology And Characteristic
  • 8. • Pyroglyphid mites dominate (D.pteronyssinus, D. farinae, Euroglyphus maynei)  Dust mite • Tropical areas: Blomia tropicalis • Occasionally storage mites: Lepidoglyphus destructor, Tyrophagus putrescentiorThomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 9. Dust mite• In most humid areas of the world, house dust mites are the major source of allergens in house dust• Pyroglyphid mites are eight-legged and sightless (microscopic arthropods) (0.3 mm in length)• Live on skin scales and other debris• Very precarious water balance• Mites growth dependent on 􀂄 water in ambient air (not capable of searching for or drinking liquids) 􀂄 relative humidity >50% 􀂄 absolute humidity ≥6 g/kg 􀂄 temperature of 65-80 F (18.3-26.7 C) Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552 Immunol Allergy Clin N Am 31 (2011) 493–507
  • 10. Dust mite• As humidity falls,it may take months for mites to die and longer for allergen levels to decrease in carpets, sofas, or mattresses• Fecal particles : – 10-35 μm in size (similar to pollen grains) – particles contain digestive enzymes – surrounded by a chitinous peritrophic membrane – „membrane‟ is not waterproof, and allergens elute from fecal particles rapidly • Mite bodies and fecal pellets are the major sources of allergens •Settle out of air quickly so airborne levels depend upon disturbance in room Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 11. Dust mite• Dust mite allergen : bed room• Cockroach allergen : kitchen• A major problem with any assessment of exposure to dust mite antigens is that patients often sleep or sit with their heads very close to mite-infested material (e.g., sofas, blankets, pillows, carpet) Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 12. www.allergen.org
  • 13. www.allergen.org18 Feb 2013
  • 14. Dust mite• mite allergens are now referred to as – group 1 (Der p 1 and Der f 1) – group 2 (Der p 2 and Der f 2)• Der f 1 and Der p 1 are highly cross-reactive as are Der f 2 and Der p 2• Der f/p 10 (tropomyosin) cross reacts with other invertebrate tropomyosins such as shrimp• Antibodies to B. tropicalis cross-react partially with other dust mites• dust levels of mite allergen (Der p 1 + Der p 2) – sensitization at 2-10 μg/g of dust – For nonallergic children higher “threshold” of 20 μg/g Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 15. Dust mite• Avoidance measures
  • 16. Otolaryngol Clin N Am 44 (2011) 711–725
  • 17. Avoidance• standard part of the treatment of allergic disease• difficult to achieve, particularly in home environments• Many patients, despite being skin test positive, were not aware that dust related to their symptoms• sources and nature of indoor allergens were not well understood, advice offered on avoidance was often inadequate or even wrong• The complexity and nonlinearity of dose response relationships also makes such evaluations of the effectiveness of allergen avoidance difficult Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552 Immunol Allergy Clin N Am 31 (2011) 493–507
  • 18. Br Med J 1998; 317:1105
  • 19. 2001 : 29 trials (939 patients)2004 : 49 trials (2733 patients)2008 : 54 trials (3002 patients)2011 : 55 trials (3121 patients)
  • 20. 26 trials : physical10 trials : chemical methods8 trials : combination Cochrane Library 2011, Issue 10
  • 21. Cochrane Library 2011, Issue 10
  • 22. Cochrane Library 2011, Issue 10
  • 23. • The variability applies to the evaluation of patients, the intervention used, and the assessment of outcome• Meta-analysis is only valid when the studies are comparable, and this may not be true for the successful studies on allergen avoidance J Allergy Clin Immunol 2008;122:694-6 very different designs and engage different subjects, time frames, controls, seasons, and methods of intervention J Allergy Clin Immunol -
  • 24. longer than 6 monthsThomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 25. CURRENT MEDICAL GUIDELINES AND ALLERGEN AVOIDANCE• most professional guidelines for asthma management advocate the avoidance of acute allergen „„triggers,‟‟• there is a diversity of views about the role of allergen avoidance practices in long-term disease management• 2007 National Heart Lung and Blood Institute : EPR3 (US) report – advises that the first and most important step in controlling allergen induced asthma is to reduce exposure. J Allergy Clin Immunol -
  • 26. CURRENT MEDICAL GUIDELINES AND ALLERGEN AVOIDANCE• Finnish Allergy Program 2008-2018 – promotes holistic „„allergy health‟‟ through diet and physical activity and advocates allergen avoidance only „„in mandatory situations.‟‟• Both the 2009 Global Initiative for Asthma and the British Thoracic Society guidelines reflect (Cochrane review) – no consistent evidence for allergen avoidance in preventing asthma – only tenuous evidence that reducing allergen exposure can reduce asthma morbidity J Allergy Clin Immunol -
  • 27. ICON pediatric asthma• some ambiguity with respect to the role of allergen avoidance• JGCA, NAEPP3, and PRACTALL – specific recommendations for the reduction in allergen exposure for sensitized patients with asthma• AAMH, GINA, and SIGN – unproven effectiveness of current avoidance strategies on asthma control• a multifaceted, comprehensive approach is prerequisite for clinical benefit Allergy 2012; 67: 976–997
  • 28. Cochrane Database of Systematic Reviews 2010, Issue 7.
  • 29. House dust mite avoidance measures for perennial allergic rhinitis• 9 trials involving 501 participants• 2 studies investigating the effectiveness of mite impermeable bedding covers were of good quality• 7 studies were small and of poor quality• 2 trials investigated the efficacy of acaricides• 2 trials investigated the role of high-efficiency particulate air (HEPA) filters• 1 trial, using a factorial design, investigated the efficacy of both acaricide and house dust mite impermeable bedding covers in isolation and combination• Remaining 4 trials investigated the efficacy of bedroom environmental control programmes involving use of house dust mite impermeable bedding covers Cochrane Database of Systematic Reviews 2010, Issue 7.
  • 30. House dust mite avoidance measures for perennial allergic rhinitis• Trials to date  small and of poor methodological quality• difficult to offer any definitive recommendations on the role• use of acaricides and extensive bedroom-based environmental control programmes may be of some benefit in reducing rhinitis symptoms  but the evidence is not strong• Isolated use of house dust mite impermeable bedding is unlikely to prove effective• More research is needed Cochrane Database of Systematic Reviews 2010, Issue 7.
  • 31. METHODS OFMITE ALLERGEN AVOIDANCE
  • 32. Method• Physical method – Encasing of bedding – Vacuums cleaners – Floor coverings – Laundry – Air filtration• Chemical method – Acaricide
  • 33. Encasings• In the bedroom, covering mattresses and pillows with impermeable covers is effective• This effect may be large, variable, and persist for a couple of months• Encasings differ widely in their quality – some cheap brands have large pores, other multilayered encasings delaminate, and others harbor mites• Tightly woven synthetic or cotton fabrics are preferred• Most trials of encasings have failed to regularly wash them (difficult with some encasings), which renders them ineffective as allergens build up on the outer surface within several weeks Curr Allergy Asthma Rep 2008;8:126-32 Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 34. 16 tightly woven:9 United States3 Japan2 Thailand1 Germany1 France J Allergy Clin Immunol -
  • 35. laminate-coated and loosely woven cover molting among nonwoven fibersdead mites on an acaricide-coated and nonwoven cover group of mites in the matrix of a nonwoven cover J Allergy Clin Immunol -
  • 36. Nonwoven easy access for mites to readily penetrate into the substrate of the material before after J Allergy Clin Immunol -
  • 37. tightly woven fabric with systematized regular fibers allowing littlespace for penetration. J Allergy Clin Immunol -
  • 38. • Woven, nonwoven – pore size between 2 and 10 um (average, 6 um)  blocking most mite allergens• Plastic – pore free , best barrier in terms of blocking – but the least comfortable : zero ventilation – tendency to become a haven for mold spores• For acaricide-coated materials – pore size is usually not a major factor – mites are eradicated on contact with the chemicals – still allow the passage of allergens – prevent penetration through the fabrics, but allow colonization J Allergy Clin Immunol -
  • 39. sponge-like polyurethane : lowest rate Synthetic fibers and kapok mattresses : highest rate Symptomatic level Sensitized levelA combination of the following: choosing new sponge-like polyurethane or coconut fiber mattresses withmite-impermeable covers and washing sheets,pillowcases, blankets, and mattresses pad at leastweekly in hot water should be the best method ofprevention in HDM allergen sensitive allergic patients Asian Pac J Allergy Immunol 2010;28:155-61
  • 40. Laundry• Both dust and cat and mite allergens are effectively removed by laundry – physical removal of both dust and mites by the multiple wash and rinse cycles; – effects of detergents additives – subsequent drying procedures• McDonald LG,Tovey E. * – All mites were killed by water temperatures 55 degrees C or greater – Killing at lower temperatures was not enhanced by any of the pure detergents or laundry products tested * J Allergy Clin Immunol 1992;90:599-608 J Allergy Clin Immunol -
  • 41. Floor coverings• Designing the house with polished floors and wooden or vinyl/leather furniture so as to limit the sites where mites can grow• carpets fitted onto unventilated floors  water can accumulate  growth of both fungi and mites• hard floors are likely to be preferred as they are more easily kept in a state that minimizes aeroallergen reaerosolization in the long term• the little available data of aeroallergens in houses suggest that the difference may be small and the effects complex Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552 J Allergy Clin Immunol -
  • 42. Vacuum cleaners• Vacuum cleaners are heavily promoted• Probably all cleaners cause a brief increase in personal aeroallergen exposure under normal domestic conditions and high- efficiency particulate arrest (HEPA) filters make little difference• Thus, the benefits of HEPA filtration on exposure may have been exaggerated and all cleaners probably provide a brief increase in exposure. J Allergy Clin Immunol -
  • 43. Allergy 2006;61:119-23
  • 44. Air management• indoor relative humidity is kept below 50% (absolute humidity below 6 g/kg)• In some areas of the world this can be done by increasing ventilation• in other areas it is necessary to use air conditioning during the most humid months of the summer Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 45. Air filtration• The role of air filtration continues to be debated• There is some consensus that small benefits exist, mainly for pet allergens J Allergy Clin Immunol -
  • 46. Acaricides• variety of acaricides have been used to treat carpets or furniture• pyrethroids, natamycin (an antifungal), pirimiphos methyl, and benzyl benzoate• killing mites• Acaricides proved largely ineffective because the mite populations return shortly after their application and they may also cause skin and respiratory irritation• No data on clinical benefit exist, and concerns about human health and environmental toxicity remain J Allergy Clin Immunol - Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 47. Acaricides• 1% or 3% tannic acid – method of denaturing mite allergens – reduction of mite allergen can be achieved, – does not kill mites – so the effect can only be temporary, approximately 6 weeks to 3 months• may be recommended when it is not possible to remove the carpets or change the furniture Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 48. Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 49. Immunol Allergy Clin N Am 31 (2011) 493–507
  • 50. Cockroach• Biology And Characteristic
  • 51. Cockroaches• Phylum Arthropoda, class Insecta, order Blattaria• major source of indoor allergens, especially in inner cities• allergens can be derived from feces, saliva, or debris from dead animals• Most common species indoors: 􀂄 Blattella germanica, German 􀂄 Periplaneta americana, American• World wide distribution• Highest levels usually in kitchens (mite allergen :in bedding) Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 52. Cockroaches• Allergens not easily detected in undisturbed air, large particles (like dust mites) >10 μm in diameter, and that consequently fall rapidly• Large quantities of cockroach allergens can accumulate in homes and may remain for years after cockroaches have been eradicated• it was the concentration of cockroach allergen in children‟s bedrooms that correlated with the risk of hospitalization Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 53. American cockroach (Periplaneta americana)German cockroach (Blattella germanica) oriental cockroach (Blatta orientalis)
  • 54. www.allergen.org 21/2/2013
  • 55. Cockroach• Avoidance Measures
  • 56. Cockroach• Pest allergens appear to be particularly difficult to eliminate and require different strategies than those used for other indoor allergens• These interventions include initial removal of the insects, rodents, or both but also require long-term care to prevent a return of the infestation J Allergy Clin Immunol 2010;125:575-81
  • 57. J Allergy Clin Immunol 2010;125:575-81
  • 58. Cockroaches• effective when applied as part of an overall avoidance planThe primary strategies are:(1) poison bait Bait for killing cockroaches ranges from boric acid, to a variety of chemicals including hydramethylnon, abamectin, and fipronil(2) careful housekeeping to enclose all sources of food for insects(3) cleaning to remove any accumulated allergen(4) sealing all possible access points to the house• Spraying with insecticides – is generally ineffective – volatile organic substances used are often irritating to patients with asthma Thomas A.E. Platts-Mills.Middleton‟s Allergy 7‟th edition ,539-552
  • 59. Cockroach• Once cockroaches have been eliminated from the environment,• a thorough cleaning is necessary• not only immediately after pesticide treatment• but continued for long periods of time (up to several months) to remove the allergen Immunol Allergy Clin N Am 31 (2011) 493–507
  • 60. Immunol Allergy Clin N Am 31 (2011) 493–507
  • 61. Pediatr Clin N Am ( ) –
  • 62. Summary• Many different allergens are found indoors, but dust mite, cat, cockroach, mouse, and dog appear to be the most important• single interventions for indoor allergens have limited effectiveness• multifaceted, comprehensive approach is prerequisite for clinical benefit• Complete allergen avoidance is usually impractical, or impossible, and often limiting to the patient• some measures involve significant expense and inconvenience• tailoring environmental interventions to specific sensitization profiles has been shown to be of added value It is also necessary to tailor interventions to an individual‟s living situation and patterns of disease
  • 63. Thank you

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