Contamination of nebulizer equipment with cockroach allergen: there's a bug in the system!

BACKGROUND: Physicians often have anecdotal reports of patients describing increased asthma symptoms after the use of nebulizers; however, there are few published reports of nebulizer-associated exacerbations. OBJECTIVE: To present 2 cases of asthmatic children who experienced a life-threatening exacerbation of their symptoms after nebulizer use. METHODS: Case 2's nebulizer was tested for cockroach allergen by washing the medication reservoir with 2 mL of sterile filtered 1% phosphate-buffered saline, 0.05% bovine serum albumin, and Tween 20 overnight with rotation. The patient's sealed albuterol nebulizer medication was used as a control. The control albuterol and test solutions were analyzed for Blattella germanica 1 and 2 allergens using a monoclonal antibody-based immunoenzymetric assay. RESULTS: The reservoir from case 2 was found to have measurable levels of both Bla g 1 and Bla g 2. The control albuterol solution had no measurable cockroach allergen. An insect found in the nebulizer box of case 2 was identified as an infantile German cockroach. CONCLUSIONS: Nebulizer use provides an opportunity for antigen exposure directly to small airways, which may lead to severe allergic reactions in patients using contaminated equipment.     

Monthly measurements of indoor allergens and the influence of housing type in a northeastern US city.

BACKGROUND: We examined seasonal variation of dust-mite (Der f 1 and Der p 1), cat (Fel d 1), and cockroach (Bla g 1) allergens in Boston, while adjusting for other covariates. Limited data are available on seasonal patterns of indoor allergen concentrations for different geographic regions in the USA. Understanding within-home seasonal variation of allergens is important epidemiologically and clinically. METHODS: From June 1995 to June 1996, dust samples were vacuumed monthly from the bed, bedroom floor, and kitchen of 20 homes. Indoor temperatures were measured monthly and used in calculating relative and absolute humidity. Monthly home characteristics questionnaires were completed by an adult resident of each home. Dust samples were assayed by enzyme-linked immunosorbent assays. RESULTS: Der f 1 and Der p 1 in beds and floors peaked in the autumn months, Fel d 1 peaked in winter and spring, and Bla g 1 was highest in summer. Dust-mite allergen concentrations were 1.9-2.4 times higher in autumn than spring, but the levels in beds were 19-31 times higher in houses than those in apartments. Although Fel d 1 levels in beds were 2.4 times higher in spring than summer, homes with cats had levels 224 times higher than those without cats. Similarly, Bla g 1 levels in kitchens were 2.1 times higher in summer than winter, but apartments had levels five times higher than those of houses. CONCLUSIONS: Sampling season is a source of within-home dust-mite, cat, and cockroach allergen variation in the northeastern USA. However, the influence of housing type and owning a cat far outweighed the seasonal variation of these indoor allergens.     

Domestic allergens in public places II: dog (Can f 1) and cockroach (Bla g 2) allergens in dust and mite, cat, dog and cockroach allergens in the air in public buildings

Background Sensitization and exposure to indoor allergens are the major risk factors for asthma. It is possible that significant exposure to domestic allergens occurs outside the home. Objectives To investigate the levels of Can f 1 and Bla g 2 in the dust from carpeted floors and upholstered seats in public buildings and public transport and the airborne concentrations of Der p 1, Fel d 1, Can f 1 and Bla g 2 in schools and offices. Methods Can f 1 and Bla g 2 were measured in the dust collected by vacuuming a I m² area of carpet, as well as upholstered seats in five schools, six hotels, four cinemas, six pubs, three buses and two trains. Dust was also collected from the bedroom carpet, living room carpet, mattress and sofa in 20 homes with and 20 homes without a dog in the same area. Personal airborne sampling (2 L/min) was conducted for 8 h in offices (n= 16) and classrooms (n= 9). In addition, airborne samples in schools were collected using a high volume pump (60 L/min) for 1 h in three classrooms immediately after the children vacated the school. Can f 1, Bla g 2, Der p 1 and Fel d 1 were assayed using a two–site monoclonal antibody–based ELISA. Results Can f 1 was detected in all dust samples from public places, ranging from 0.2 to 52.5 μg/g, Significantly higher levels were found in upholstered scats (geometric mean – GM 9.4 μg/g) than in carpets (GM 1.5 μg/g; P < 0.001), and levels of Can f 1 > 10 μg/g were found in 40% of upholstered seats in public places. Can f 1 was significantly higher in upholstered seats in public places than in sofas in homes without a dog (GM 1.8 μg/g; P < 0.001). Detectable levels of Bla g 2 were found in all of the schools (GM 2.4 U/g, range 0.8–4.4 U/g). Bla g 2 concentration greater than 2U/g (provisional threshold level representing risk of sensitization) was measured in 65% of the classrooms sampled. Der p 1 and Bla g 2 were below the detection limit in all airborne samples. However, airborne Fel d 1 and Can f 1 were detected in schools and offices, albeit in low concentrations. Conclusions Upholstered seats from public places constitute a reservoir for the accumulation of dog allergen, and a source of exposure to Can f 1 inside public buildings or on public transport. Exposure to cockroach allergens in schools may be important for cockroach sensitized asthmatic children.     

Environmental allergens and asthma in urban elementary schools.

BACKGROUND: Asthma in school children is rising, and indoor allergens are very common triggers of asthma attacks; however, the risk of the school environment on asthma has not been well studied. OBJECTIVE: To determine the presence and the levels of common aeroallergens in schools, where asthma prevalence rates are high. METHODS: Settled dust samples were collected from 12 Baltimore City public elementary schools, and they were analyzed for the following allergens: cockroaches (Bla g 1/2), dust mites (Der f 1/p 1), dog (Can f 1), cat (Fel d 1), and mouse (Mus m 1). School asthma prevalence rates were correlated with allergen levels, and association between allergen levels and other risk factors present in the schools' environment was examined. RESULTS: The mean and range levels were 1.49 U/g (0 to 8) for Bla g 1/2; 0.38 microg/g (0 to 11.9) for the Der f 1/p 1; 1.44 microg/g (0.1 to 9.6) for Can f 1; 1.66 microg/g (0.2 to 12) for Fel d 1; and 6.24 microg/g (0.3 to 118.3) for Mus m 1. Dust mite, cat and dog allergens were significantly in rooms with carpet and/or area rugs, compared to rooms with bare floors (P < 0.05). Asthma prevalence rates varied from 11.8 to 20.8% between schools and positively correlation with the mean levels of Bla g 1/2 in the schools (P = 0.001). CONCLUSIONS: Common allergens that are known to trigger asthma were detected in all school environments, where asthma prevalence rates were high. However, the overall allergen levels were low, indicating that other factors, including exposures in the homes of asthmatic patients, may have more relevance to sensitization and symptoms than school exposures.     

Cat (Fel d I), dog (Can f I), and cockroach allergens in homes of asthmatic children from three climatic zones in Sweden

We have investigated the levels of cat ( Fel d I), dog ( Can f I), and cockroach ( Per a I) allergens in dust from bedrooms, living rooms, kitchens, and bathrooms from 123 homes of asthmatic children in three zones of Sweden with varying climates. Absolute indoor humidity (AIH), relative humidity (RH), rate of ventilation in air changes per hour (ach), and number of airborne particles were also measured. Fel d I, Can f I, and Per a I allergen contents were determined by mab ELISA, and the levels were related to various environmental factors. The major cat allergen. Fel d I, was detected in all homes, and the concentrations varied between 16 ng and 28000 ng/g fine dust. The dog allergen, Can f I, was detected in 85% of the homes, and the levels varied from 60 ng to 866000 ng/g dust. Cockroach allergen was detected in only one home (40 ng/g). Fel d I and Can f I allergens were equally distributed geographically. Dust from living rooms contained significantly higher ( P < 0.05) concentrations of both Fel d I and Can f I allergens than dust from bedrooms, kitchens, and bathrooms. The levels tended to be higher in homes with poor ventilation (<0.5 ach) and in homes with wall-to-wall carpets. Significantly higher ( P < 0.01) numbers of airborne particles were found in homes with high humidity (i.e., AIH ≥ 7 g/kg or RH ≥ 45%). We conclude that pet allergens are ubiquitous in different climatic regions, being found in bedrooms, living rooms, kitchens, and bathrooms. Current or previous presence of a cat or dog, high indoor humidity, presence of wall-to-wall carpets, and poor ventilation all increase the risk for high allergen exposure. In contrast, cockroach allergens arc rarely found in a temperate climate.     

Relationship between mite, cat, and dog allergens in reservoir dust and ambient air

BACKGROUND: Standardized methods to measure allergen exposure are essential to assess the relationship between exposure, sensitization, and asthma. Most studies have measured allergen levels in reservoir dust, although air samples may be more representative as a measure of inhaled allergen. The aim of this study was to define the relationship between mite, cat, and dog allergen content in the reservoir dust and the levels in the ambient air. METHODS: Dust samples from the living-room floor (LF) and sofa (S) were collected in 127 homes: 62 without and 65 with pets (31 dogs, 34 cats). Air samples were taken in the same room, with a high-volume pump for 1 h (flow 60 l/min). Der p 1, Fel d 1, and Can f 1 were determined by mAb-based ELISA. RESULTS: Airborne Der p 1 was below the detection limit (0.8 ng/m3) in all homes, with reservoir levels (GM and range) being 1.14 microg/g (0.2-66) and 1.15 microg/g (0.2-127) in LF and S, respectively. Airborne Can f 1 was detected in 40/62 homes without pets (range 0.6-12.4 ng/m3) and in all homes with dogs (range 0.5-99 ng/m3). In the multiple linear regression analysis, Can f 1 level in the LF was an independent correlate of the airborne Can f 1 (P=0.01, homes with dogs; P=0.04, homes without dogs). Fel d 1 was detected in the air in 16/62 homes without pets (range 0.16-1.8 ng/m3) and in all homes with cats (range 0.4-22.3 ng/m3). Fel d 1 level in the LF was an independent correlate of the airborne Fel d 1 in homes without cats (P=0.008), but airborne levels in homes with cats did not correlate with reservoir levels. CONCLUSIONS: The aerodynamics of each allergen must be taken into account when assessing exposure: while levels in reservoir dust are the best available index for mite allergens, airborne levels might be more suitable for defining exposure to pets. If air samples are difficult to obtain, levels of Can f 1 and Fel d 1 in the LF samples should be used as a surrogate measure of personal exposure.     

Pet allergen levels in homes in Ghana and the United Kingdom.

The frequency of cat and/or dog ownership in Ghana is comparable to that in the United Kingdom (approximately 50%). However, in Ghanaian communities pets are predominantly kept outdoors. Levels of pet allergens (Fel d 1 and Can f 1) in 100 Ghanaian homes (49 without pets) were compared with levels in 410 homes in the United Kingdom (258 without pets). Homes with pets in the United Kingdom contained much higher allergen levels than homes with pets in Ghana (for Fel d 1: mean difference, 275-fold; 95% CI, 129-fold to 594-fold; P <.0001; for Can f 1: mean difference, 75-fold; 95% CI, 33-fold to 169-fold; P <.0001). Homes without cats in the United Kingdom contained significantly higher levels of Fel d 1 than homes with cats in Ghana (mean difference, 3.7-fold; 95% CI, 2.0-fold to 7.2-fold; P <.0001). In the United Kingdom, homes with dogs contained 75-fold (95% CI, 47-fold to 139-fold) more Can f 1 than homes without dogs, whereas in Ghana, homes with dogs contained 3.1-fold (95% CI, 1.5-fold to 6.1-fold; P =.003) more Can f 1 than homes without dogs. In the United Kingdom, homes with cats contained 77-fold more Fel d 1 (95% CI, 46-fold to 129-fold; P <.0001) than homes without cats; there was no difference in cat allergen levels between homes with cats and homes without cats in Ghana. In conclusion, levels of pet allergens in Ghanaian homes with pets were (1) between 75-fold (dog) and 275-fold (cat) lower than levels in homes with pets in the United Kingdom and (2) lower than or comparable to levels in homes without pets in the United Kingdom.     

Dog allergen (Can f 1) and cat allergen (Fel d 1) in US homes: results from the National Survey of Lead and Allergens in Housing

BACKGROUND: Exposures to dog and cat allergens are believed to play important roles in the etiology of asthma; however, the levels of these allergens have never been assessed in a representative sample of US homes. OBJECTIVE: The objective of this study was to estimate and characterize exposures to Can f 1 (dog allergen) and Fel d 1 (cat allergen) in US homes. METHODS: Data were obtained from the National Survey of Lead and Allergens in Housing, a nationally representative survey of 831 US homes. Vacuumed-collected dust samples from the bed, bedroom floor, living room floor, and living room sofa were analyzed for concentrations of Can f 1 and Fel d 1 (micrograms of allergen per gram of dust). RESULTS: Although a dog or cat had lived in only 49.1% of homes in the previous 6 months, Can f 1 and Fel d 1 were detected in 100% and 99.9% of homes, respectively. Averaged over the sampled sites, geometric mean concentrations (microg/g) were 4.69 for Can f 1 and 4.73 for Fel d 1. Among homes with an indoor dog and cat, respectively, geometric mean concentrations were 69 for Can f 1 and 200 for Fel d 1. Among homes without the indoor pet, geometric mean concentrations were above 1.0. The independent predictors of elevated concentrations in homes without pets were all demographic variables that were also linked to a higher prevalence of pet ownership. CONCLUSIONS: Can f 1 and Fel d 1 are universally present in US homes. Levels that have been associated with an increased risk of allergic sensitization were found even in homes without pets. Because of the transportability of these allergens on clothing, elevated levels in homes without pets, particularly among demographic groups in which pet ownership is more prevalent, implicate the community as an important source of these pet allergens.     

Indoor allergens and longitudinal FEV 1 decline in older adults: The Normative Aging Study

We investigated the relationship between home allergen exposure and decline in FEV₁ in 10 asthmatic and 30 randomly selected, age-matched, nonasthmatic participants in the Normative Aging Study. We defined asthma as subject-reported wheezing apart from colds, with either a physician's diagnosis of asthma or a methacholine PD₂₀ FEV₁ of 8.6 μmol or less. We examined the relationship between the annual decline in FEV ₁ and the concentrations of the cockroach (Blattella germanica) allergens Bla g 1 and Bla g 2, the dust mite (Dermatophagoides pteronyssinus and Dermatophagoides farinae) allergens Der p 1 and Der f 1, and the cat (Felis domesticus) allergen Fel d 1 in house dust specimens. Bla g 1 (–79.8 ml/yr, p = 0.0006) and Bla g 2 (–40.81 ml/yr, p = 0.0004) were significant predictors of decline in FEV₁ after adjustment for age, smoking, and baseline FEV₁. These results were unchanged after elimination of the asthmatic subjects from the analysis. We conclude that cockroach allergen levels in homes is a risk factor for accelerated decline in FEV₁ independent of airway responsiveness. (J Allergy Clin Immunol 1998;101:720–5.)     

Exposure to indoor allergens in day-care facilities: results from 2 North Carolina counties

BACKGROUND: With 63% of US children under 5 years of age in regular child care, day-care facilities could be an important source of exposure to indoor allergens. OBJECTIVE: This study examined levels of 7 indoor allergens in 89 day-care facilities in 2 North Carolina counties. METHODS: At each facility, a questionnaire was administered, observations were made, and vacuumed dust samples were collected from carpeted and noncarpeted areas of one room. Allergen concentrations were measured with antibody-based ELISAs. RESULTS: Each allergen was detected in a majority of facilities (52% to 100%). Geometric mean concentrations were 5.19 mug/g for Alternaria alternata , 2.06 mug/g for Can f 1, 1.43 microg/g for Fel d 1, 0.21 U/g for Bla g 1, 0.20 microg/g for Der p 1, 0.10 microg/g for Der f 1, and 0.01 microg/g for Mus m 1. Concentrations for 5 of the 7 allergens were not statistically different from concentrations found in southern US homes sampled in the National Survey of Lead and Allergens in Housing. In rooms with carpet and hard-surfaced flooring, levels of A alternata , Can f 1, Der f 1, Der p 1, and Fel d 1 were statistically higher on carpet. CONCLUSIONS: In this survey of day-care facilities in North Carolina, detectable levels of indoor allergens were commonly found. For many young children and day-care staff, day-care facilities might be a source of clinically relevant exposures to indoor allergens.     

Classroom aeroallergen exposure in Arkansas head start centers.

BACKGROUND: The impact of preschool environmental conditions on classroom aeroallergen concentrations is not fully understood. OBJECTIVE: To examine the relationship between school environmental conditions and classroom aeroallergen concentrations in the Pulaski County Head Start (HS) Program. METHODS: Thirty-three HS centers in Pulaski County, Arkansas, underwent a detailed environmental evaluation. Classroom settled dust samples were analyzed for the presence of common indoor allergens. RESULTS: Classroom eating (70%), wall-to-wall carpeting (58%), and water damage (33%) were common. Median classroom allergen levels were as follows: dust mite (Der p 1 and Der f 1), 0.6 microg/g; Fel d 1, 0.4 microg/g; Can f 1, 1.7 microg/g; cockroach, below detection; Mus m 1, 0.18 microg/g; and mold spores, 17,800 CFU/g. Can f 1 and Mus m 1 allergens were detected in 100% of HS centers. Facilities with carpeting, increased humidity, and single-use facilities showed trends toward increased dust mite concentrations. Detectable cockroach allergen was more common in classrooms cleaned by teachers than by professional housekeepers. CONCLUSIONS: Aeroallergens were commonly detected in Pulaski County HS center classrooms, with dog and mouse allergens detected in 100% of centers. Median classroom allergen concentrations were low, and classroom characteristics were not strongly predictive of increased allergen exposure.     

Sensitization to cat allergens in non-cat owner patients with respiratory allergy.

BACKGROUND: Cats represent one of the most important sources of indoor allergens. The sensitization rate can reach up to 60% in western countries. Keeping cats indoors is uncommon in big cities in Turkey, but cats living in the streets are common. OBJECTIVE: To investigate the prevalence of sensitization to cats in patients with respiratory allergy from Izmir, Turkey, and its relationship to home cat allergen levels. METHODS: A total of 387 patients (70.8% female; mean age, 34.3 years) with respiratory allergic diseases (rhinitis and/or asthma) were included in this study. Skin prick test to cat was performed. House dust samples were collected from the living room of 25 patients and 14 healthy subjects. The major cat allergen (Fel d 1) levels were measured by Dustscreen. Fel d 1 levels given by the manufacturer were as follows: 0.05, 0.13, 0.40, 1.1, and 6.2 mU/mL. RESULTS: The prevalence of cat sensitivity was 44.7% (n = 173). Only 6 patients (1.6%) had a history of feeding a cat in their houses. Thirty-six (92%) of 39 houses had detectable levels of cat allergen (mean Fel d 1 level, 2.24 +/- 2.69 mU/mL). The mean Fel d 1 levels were 1.58 +/- 2.51 mU/mL in the healthy group, 1.91 +/- 2.61 mU/mL in the asthmatic group, and 3.26 +/- 2.85 mU/mL in the group with allergic rhinitis (P = 0.12). The prevalence of cat sensitivity in patients who had 1.1 mU/mL of Fel d 1 in their homes was 57.1%. This rate was five times lower (11.1%) in patients who had the highest Fel d 1 level (6.2 mU/mL) in their homes. CONCLUSIONS: The prevalence of cat sensitivity in Izmir, where cats are generally not kept within homes, is as high as in western countries. The sampled houses have measurable levels of Fel d 1 even in the absence of indoor cats. High prevalence of cat sensitivity in Izmir is probably due to indirect exposure.     

Children at risk for asthma: home allergen levels, lymphocyte proliferation, and wheeze

BACKGROUND: Allergic asthma is a common childhood disease. Although T-lymphocyte activation plays a critical role in allergic asthma, the environmental factors promoting lymphocyte activation in children are not well defined. OBJECTIVE: In a cohort of children at risk for asthma (n = 114), we determined whether the levels of cockroach (Bla g 1 or 2), house dust mite (Der f 1), and cat allergen (Fel d 1) in the home during infancy was associated with subsequent allergen-specific lymphocyte proliferation in later life. METHODS: Dust samples from multiple sites in the home were collected at 3 months of age and were measured for allergen levels. Serial questionnaires were applied. At a median age of 2 years, PBMCs were isolated and lymphocyte proliferation to the home allergens and PHA was determined. RESULTS: Increased lymphocyte proliferative responses to Bla g 2 were associated with higher home levels of Bla g 1 or 2 (P for trend with kitchen Bla g levels =.011), in analyses adjusting for cold in the past week. Proliferative responses to Der f 1 were higher in homes with family room levels of Der f 1 > or =10 microg/g dust than in homes with Der f 1 <2 microg/g, but differences were not significant in analyses adjusting for cold (P =. 15). Repeated wheeze in the first 2 years of life was associated with increased allergen-specific and PHA proliferative responses. CONCLUSION: Early-life cockroach allergen exposure at 3 months of age predicts allergen-specific lymphocyte proliferative responses at a median of 2 years of age.     

Cat, dog, and house-dust-mite allergen levels of house dust in Finnish apartments

The presence of indoor allergetis iti Finnish homes was studied for the first time. Dust samples (n=30) were collected by vacuuming a 1 m² area from a living-room carpet in 30 apartments divided into three groups: homes with cats (n = 10), homes with dogs (n = 10). and homes without pets (n=10). The levels of major cat (Fel d 1). dog (Can f 1), and house-dust-mite (Der p 1) allergens were analyzed by two-site ELISA methods. Der p 1 levels were below the detection limit in all dust samples. In the homes with cats or dogs, Fel d 1 and Can f 1 levels ranged from 147 to 2800 μg/g (geometric mean 567 μg/g), and from 86 to 1400 μg/g (geometric mean 296 μg/g), respectively, being slightly higher than those reported elsewhere. Low allergen levels, mainly below 3 (μg/g. were also detected in the homes without pets, indicating the transfer of allergens from place to place. However, in 25% of these samples, allergen levels exceeded the proposed threshold levels for cat or dog sensitization. The presence of pets was the most significant factor affecting cat and dog allergen levels in the house dust, and other factors, such as the amount of dust collected, residential time, and cleaning habits, had no or only a weak effect on allergen levels.     

Inner City Asthma Study: relationships among sensitivity, allergen exposure, and asthma morbidity

BACKGROUND: Asthma-associated morbidity is rising, especially in inner city children. OBJECTIVE: We evaluated the allergen sensitivities, allergen exposures, and associated morbidity for participants in the Inner City Asthma Study. We also determined geographic variations of indoor allergen levels. METHODS: Nine hundred thirty-seven inner city children 5 to 11 years old with moderate to severe asthma underwent allergen skin testing. Bedroom dust samples were evaluated for Der p 1, Der f 1, Bla g 1, Fel d 1, and Can f 1. RESULTS: Skin test sensitivities to cockroach (69%), dust mites (62%), and molds (50%) predominated, with marked study site-specific differences. Cockroach sensitivity was highest in the Bronx, New York, and Dallas (81.2%, 78.7%, and 78.5%, respectively), and dust mite sensitivity was highest in Dallas and Seattle (83.7% and 78.0%, respectively). A majority of homes in Chicago, New York, and the Bronx had cockroach allergen levels greater than 2 U/g, and a majority of those in Dallas and Seattle had dust mite allergen levels greater than 2 microg/g. Levels of both of these allergens were influenced by housing type. Cockroach allergen levels were highest in high-rise apartments, whereas dust mite allergen levels were highest in detached homes. Children who were both sensitive and exposed to cockroach allergen had significantly more asthma symptom days, more caretaker interrupted sleep, and more school days missed than children who were not sensitive or exposed. CONCLUSION: Geographic differences in allergen exposure and sensitivity exist among inner city children. Cockroach exposure and sensitivity predominate in the Northeast, whereas dust mite exposure and sensitivity are highest in the South and Northwest. Cockroach allergen appears to have a greater effect on asthma morbidity than dust mite or pet allergen in these children.     

Distribution and removal of cat, dog and mite allergens on smooth surfaces in homes with and without pets.

BACKGROUND: Removing allergen from the indoor environment should be a primary strategy for the management and treatment of allergic disease. OBJECTIVE: The aims of this study were to characterize the distribution of dog, cat, and mite allergen on hard surfaces in homes with and without pets and to evaluate the efficiency of removing allergen from hard surfaces by wiping with a dry dust cloth and by vacuum cleaning using the dustbrush attachment. METHODS: The amount of allergen collected from adjacent areas of two smooth floors, a wall, and finished furniture by wiping with a Pledge Grab-it dust cloth (S. C. Johnson & Son, Inc, Racine, WI) and by brush-vacuuming were compared for 24 homes with and without pets. In addition, the areas first wiped with the dust cloth were then brush-vacuumed and the amounts of allergen collected by the first and second cleaning were compared. RESULTS: A key finding was that 23 of the 24 homes had Can f 1 allergen on one or more of the sampled areas regardless of whether a dog was present. Most homes with pets and many homes without pets had Can f 1 and Fel d 1 allergens on walls, smooth floors, and finished furniture. Carpets were the major reservoir for pet allergens in homes with pets whereas allergen was more uniformly distributed in homes without pets. Little mite allergen was found on hard surfaces even when it was present in carpets. CONCLUSIONS: Dog and cat allergens are prevalent on walls, smooth floors, and finished furniture in homes with and without pets. Dry dusting with a Grab-it dust cloth was an effective cleaning method for removing allergen from hard smooth surfaces.     

Exposure to an abundance of cat (Fel d 1) and dog (Can f 1) allergens in Swedish farming households

BACKGROUND: Earlier studies have shown that farmers are to a low degree sensitized to animal allergens. We have measured the amount of cat (Fel d 1) and dog (Can f 1) in farm households and examined the relationship between exposure and sensitization to cat and dog allergens. METHODS: Dust samples from the homes of 403 farmers who had participated in an epidemiologic follow-up study on respiratory symptoms were analyzed for allergen content by two-site ELISA methods. RESULTS: Fel d 1 was detected in 99.5% of the farmers' households ranging from 0.055 to 1455 microg/g dust in mattresses (GM 13.2) and to 3775 microg/g dust in living-room carpets (GM 17.1). Can f 1 was detected in 90.6% of the households from 0.2 to 116 microg/g dust in mattresses (GM 2.0) and to 504 microg/g dust in carpets (GM 4.3). Homes with pets present had the highest levels of the allergens (P<0.001). A total of 8.4% and 7.4% of the farmers were sensitized to cat and dog, respectively. A significant correlation was noted between exposure to the allergens and specific IgE to cat and dog, respectively (P<0.001). Sensitization to cat (OR = 4.9) and dog (OR = 17.8) was significantly associated with asthma. CONCLUSIONS: In spite of the abundance of Fel d 1 and Can f 1, farmers are only to a low degree sensitized to cats and dogs.     

Relationship among house-dust mites, Der 1, Fel d 1, and Can f 1 on clothing and automobile seats with respect to densities in houses.

BACKGROUND: Locations where there are no dust mites or pets present may contain allergens that pose a risk factor for sensitizing and inducing rhinitis and asthma. OBJECTIVE: The purpose of this study was to investigate the relationship among the prevalence of mites and mite, dog, and cat allergens in homes, on clothing, and on automobile seats. METHODS: Over a 2-year period (July 1998 to July 2000), dust mite and mite, dog, and cat allergen densities were determined in homes, associated automobiles, and on the clothing of the drivers. During this period 87 homes were sampled one to five times each. RESULTS: Low levels of live and dead mites were present in most dust samples obtained from automobile seats and in 16% from clothing. Seventy-two and 50% of the home samples had >2 microg and >10 microg Der l/g of dust, respectively, whereas 23% of automobiles seat samples had >2 microg Der l/g of dust with a mean of 1.3 microg/g. Mite and Der 1 densities were not different for homes with or without pets. However, homes with pets had significantly more Fel d 1 or Can f 1 allergen than homes without pets. Homes without cats and dogs had an average of 93 and 29 microg/g of Fel d 1 and Can f 1, respectively, which was well above threshold levels for sensitization and induction of allergic reactions. Although most clothing had detectable levels of pet allergen, the levels of these allergens were low. CONCLUSIONS: Der 1 densities in some automobiles were sufficiently high (>2 microg/g of dust) to be risk factors for sensitization and allergic reactions. However, most automobile seats had levels of dog and cat allergen that were well above the threshold levels considered to be risk factors for both sensitization and symptoms, regardless of the presence of a pet in the home. The presence of live and dead mites and mite, cat, and dog allergens in automobiles and on clothing suggests that both are vehicles in the dispersal of mites and mite and pet allergen.     

Prevalence and distribution of indoor allergens in Singapore

Background and aims Immediate hypersensitivity to indoor allergens is known to be associated with allergic asthma. This study evaluated the prevalence and distribution of six indoor allergens in 956 dust samples obtained from homes, childcare centres, schools, and a hospital in tropical Singapore. Seasonality of mite allergens was also assessed. Methods The major allergens of the Dermatophagoides spp. dust mites, Der p l and Der f 1; major cat and dog allergens, Can f 1 (dog) and Fel d 1 (cat); and cockroach, Bla g 1. were measured by specific enzyme immunoassays. Allergen levels of the storage mite. Blomia tropicalis (Blot), were measured by a fluorescent allergosorbent test (FAST) inhibition assay. Results Our results showed that homes had significantly higher concentrations and prevalence of allergens compared with the other locations, except for Bla g 1, where higher mean levels were found in schools. Within the homes, the highest concentrations of mite allergens were found in mattresses (geometric mean: 1.2 μg/g dust Der p 1; 2717 Allergen Units per gram dust [AU/g] Blot), and carpets (1.5 μg/g Der p 1; 1620 AU/g Blo t), whilst Bla g 1 was mainly concentrated in the storerooms (geometric mean = 3.5 units/g) and kitchens (geometric mean = 5.1 units/g). The major cat and dog allergens were well distributed and not confined to homes with pets. Their highest levels were found in dust of soft furnishings, carpets and mattresses. There was an absence of significant seasonal variation in Der p 1, Der f 1 and Blo t levels in the homes over a 1 year period. Conclusion The results indicate that compared with public places, the home consitutes a major reservior of indoor allergens. Allergens of the storage mite, B. tropicalis, should be considered as a major allergenic component of dust in Singapore.     

Room-specific characteristics of suburban homes as predictors of indoor allergen concentrations.

BACKGROUND: Room characteristics predicting indoor allergen exposure in suburban homes have not been clearly identified. OBJECTIVE: To examine relationships between room characteristics and concentrations of indoor allergens in homes of suburban asthmatic patients. METHODS: The homes of 339 asthmatic children ages 6 to 17 years were studied. Home inspections were conducted by a trained technician, and dust samples were analyzed for indoor allergen content. A high allergen concentration was defined as 8 microg (U)/g or more of fine dust. RESULTS: Infrequent sheet washing and wall-to-wall carpet were risk factors for high bedroom dust mite concentrations. Infrequent sheet washing was also a risk factor for high Fel d 1 concentrations. Food remains in the bedroom was a risk factor for high bedroom Bla g 1 levels, and exposed food, leaks, and dirty pots were all risk factors for high kitchen Bla g 1 levels. The combination of lack of mattress or pillow encasements, infrequent sheet washing, and carpeting was associated with a 24-fold increase in odds of a high dust mite concentration (odds ratio [OR], 24.1; 95% confidence interval [CI], 3.2-181.4). Among non-cat owners, the combination of stuffed toys on the bed, lack of mattress or pillow encasements, and infrequent sheet washing was associated with a 49-fold increase in odds of a high Fel d 1 level (OR, 49.4; 95% CI, 2.8-887.3). The combination of leaks, exposed food, and dirty pots was associated with a high kitchen Bla g 1 concentration (OR, 10.6; 95% CI, 2.8-40.5). CONCLUSIONS: Specific room characteristics predict high indoor allergen exposure among children with asthma, and a combination of these characteristics may further increase the risk of high allergen exposure.