Variability of airborne cat allergen, Fel d1, in a public place

Influence of time and phenotype on salivary Fel d1 in domestic shorthair cats

Objectives

Fel d1 is a major allergen that may affect humans sensitive to cat allergens, and it can be detected in the saliva and on the hair of cats. We studied the variability of salivary Fel d1 in typical house cats (ie, neutered domestic shorthair cats) and the factors that could be associated with that variability.

Methods

Saliva samples were collected from 64 cats, twice daily, every other day, for a year, at two locations (Missouri, USA, and Ontario, Canada). Salivary Fel d1 levels were measured using an immunoassay. Correlations and linear mixed-effects model analyses were run to assess which factors significantly affected the Fel d1 levels.

Results

Salivary Fel d1 levels varied significantly both within and among cats. Cat averages over the year ranged from 0.4–35 µg/ml, and a higher average correlated with a higher SD (P <0.001). The first collection of the day tended to be higher than the afternoon collection (P <0.001). Sex, coat color or body size did not relate to cats’ average Fel d1 production, but older cats tended to have lower salivary Fel d1 levels (P <0.001). Fel d1 levels from four samples were reliable in identifying cats producing stable low levels of Fel d1.

Conclusions and relevance

We observed a wide and continuous range of salivary Fel d1 production in domestic shorthair cats. In particular, a subset of cats had stable low levels throughout the course of the year, and they can be identified by analyzing a few saliva samples rather than their physical appearance.

Cat (Fel d 1) and dog (Can f 1) allergen levels in cars, dwellings and schools

Pets are an important source of indoor allergens. The aim of the study was to compare cat and dog allergen levels in cars, schools and homes. The study was carried out in 17 cars, 14 classrooms and 19 dwellings located in the highly industrialized and urbanized region of Poland. Dust and air samples were analyzed for Fel d 1 and Can f 1 using a double monoclonal ELISA assay. The highest amounts of cat and dog allergens (Fel d 1: 1169 μg/g; Can f 1: 277 μg/g) were found in dwellings with pets. Allergen concentrations were correlated with the number of animals kept at home. Although concentrations on automobile seats were lower, Fel d 1 levels exceeded 8 μg/g in 23.5 % of cars and high levels of Can f 1 (>10 μg/g) were found in 17.6 % of cars. The study revealed that cars of pet owners may be reservoirs of cat and dog allergens even when animals are not transported in them. In schools, concentrations of pet allergens did not reach high levels, but the moderate levels of Fel d 1 (≥1-8 μg/g) and Can f 1 (≥2-10 μg/g) were detected in 42.9 and 7.1 % of the investigated classrooms. Concentrations of cat and dog allergen in schools were higher than in homes without pets. While airborne Fel d 1 and Can f 1 levels were found low, residential allergen concentrations in settled dust and air were correlated. The study results suggest that classrooms and cars of pet owners may be important sites of exposure to cat and dog allergens, though the highest concentrations of Fel d 1 and Can f 1 are found in homes of pet owners.

Airborne allergens, endotoxins, and particulate matter in elementary schools, results from Germany (LUPE 2)

Allergic disorders are the most common childhood-related chronic diseases in developed countries. It is essential to assess the exposure, especially in schools, where children spend a large portion of their time. We aimed to investigate allergen and endotoxin levels in the air of schools and to observe seasonal variations of these factors. We evaluated airborne concentrations of house dust mites allergens (Der p 1, Der f 1), cat allergen (Fel d 1), and endotoxin in PM10 in 14 classrooms during the school days in the region of Munich, each over 20 consecutive days and in 1 classroom over the course of a year (at 83 days); we also tested outdoor air close to the schools. Endotoxin levels were quantified using two different analytical methods. In addition, indoor air climate parameters were measured. The median daily indoor CO2 and PM10 concentrations in the classrooms ranged from 423 to 3,135 ppm (median: 1,211 ppm) and 9 to 390 μg/m(3) (median: 127 μg/m(3)), respectively. Fel d 1 in the PM10 samples was the most frequently detected allergen, with levels from 0.02 to 1.15 ng/m(3) in a total of 301 samples (median: 0.19 ng/m(3), 95th percentile: 0.57 ng/m(3)). Der p 1 and Der f 1 were detected in only 51% and 19% of the samples, with 95th percentiles at 0.5 and 0.3 ng/m(3). Endotoxin levels in the PM10 and inhalable dust samples ranged from 0.5 to 84.1 EU/m(3) (median: 15.3 EU/m(3); 95th percentile: 58.2 EU/m(3)) and from 0.03 to 115 EU/m(3) (median: 8.4 EU/m(3); 95th percentile: 27.9 EU/m(3)). Fel d 1 and endotoxin were found in higher levels in the winter months. The results of the two different indoor sampling techniques for endotoxin were statistically significantly correlated. The results of airborne allergens indicate a generally low exposure level in classrooms. With regard to endotoxin, our study showed higher levels in schools compared with residences.

Can a housing environmental index establish associations between indoor risk indicators and clinical tests in persons with asthma?

The aim was to investigate the associations between indoor risk indicators, identified by a housing environmental index (HE-index), and clinical tests of lung function, allergy and bronchial hyper-responsiveness (BHR). Forty-nine eligible subjects participated in the investigation. The HE-index was based on national and international guidelines and related to measurements of humidity, temperature, carbon dioxide, formaldehyde, nitrogen dioxide, allergens and occurrence of tobacco smoke and pets. Only 18% of the investigated homes did not have any of the risk indicators. Statistically significant associations were found between exposure to mites and lung function, and to a lesser degree in BHR for subjects living in homes with pets. The cut-off levels in the HE-index were not specifically related to health effects and may therefore have been too high for sensitive persons. Further studies are needed to establish relevant guidelines for the identification of risk indicators in the housing environment for persons with asthma.

Mite and pet allergen exposure in Brazilian private cars

BACKGROUND

The role of mite and pet allergens in the development of allergic diseases has been recognized for many years.

OBJECTIVE

To determine mite (Dermatophagoides pteronyssinus [Der p 1] and Dermatophagoidesfarinae [Der f 1]), cat (Felis domesticus [Fel d 1]), and dog (Canis familiaris [Can f 1]) allergen levels in Brazilian private cars.

METHODS

Mite, cat, and dog allergens were measured in dust samples collected from 60 upholstered seats of private vehicles using enzyme-linked immunosorbent assays.

RESULTS

Mean levels of Der p 1 (0.24 microg/g of dust; range, 0.06-2.05 microg/g of dust) and Der f 1 (0.29 microg/g of dust; range, 0.06-2.07 microg/g of dust) were extremely low in most dust samples analyzed. In contrast, sensitizing mean levels of Can f 1 (1.51 microg/g of dust; range, 0.14-30.96 microg/g of dust) and Fel d 1 (0.43 microg/g of dust; range, 0.02-5.75 microg/g of dust) were observed in 32 (53%) and 12 (20%) samples, respectively. Mean Can f 1 levels were significantly higher in cars whose owners kept dogs at home (3.27 microg/g of dust) than in those without pets (0.57 microg/g of dust; P = .008). There were no significant differences in allergen levels regarding the age of the vehicle or the number of users and whether the owners transport pets inside the vehicles.

CONCLUSIONS

Private cars constitute an important pet, but not mite, allergen reservoir for continuous contamination of the indoor environment. Pet allergens may be present even in cars whose owners do not have pets. Effective measures to reduce allergen exposure in cars should be taken routinely, especially for pet-allergic patients.

Mite and cat allergen exposure in Brazilian public transport vehicles

BACKGROUND

Mites and pets are important sources of indoor allergens.

OBJECTIVES

To determine Dermatophagoides pteronyssinus (Der p 1), Dermatophagoides farinae (Der f 1), and Felis domesticus (Fel d 1) allergen levels in buses and taxis and to evaluate the predominant allergen in each vehicle type.

METHODS

Mite and cat allergens were measured using enzyme-linked immunosorbent assay in dust samples collected from upholstered seats in 60 natural-ventilation buses (NVBs), 60 artificial-ventilation buses (AVBs), and 60 taxis. Thirty dust samples from AVB air-conditioning filters were also included.

RESULTS

Levels of Der p 1 and Der f 1 were significantly higher in AVBs than in NVBs, whereas Fel d 1 levels were not significantly different between bus types. No significant differences were found in mite allergen levels in various sites in both types of buses, whereas Fel d 1 levels were significantly higher in rear and middle seats than in front seats in NVBs. Mite and cat allergen levels in taxis were significantly higher in passenger's rear seats than in driver's seats. A high proportion of dust samples from the vehicles, especially AVBs (82% for Der p 1 and 58% for Der f 1) had sensitizing levels of mite allergens, whereas more than 60% of samples from all vehicles had sensitizing levels of Fel d 1 allergen. In AVBs, samples from seats showed significantly higher levels of mite and cat allergens than those from air-conditioning filters.

CONCLUSIONS

Public transport vehicles constitute an important allergen reservoir for continuous contamination of the indoor environment.

Allergen avoidance does not alter airborne cat allergen levels in classrooms

BACKGROUND

Some schools in Sweden offer allergen avoidance classrooms for allergic children with severe asthma. However, the measures commonly used to achieve a reduction in allergen levels have not been properly evaluated. The aim of the present prospective study was to study whether the levels of airborne cat allergen are altered after introducing feasible intervention measures in classrooms, without interfering with peoples' freedom of choice regarding pet ownership.

METHODS

Twenty-five classes, including five established allergy prevention classrooms participated in the study during a school year. After one term, six classes underwent a number of intervention measures recommended by the Swedish National Institute of Public Health. Curtains, upholstery and plants were removed, bookshelves were replaced with cupboards and regular cleaning was increased. Airborne dust was collected weekly (32 weeks) using duplicate Petri dishes (n = 1574) and on six occasions using two personal air samplers in each class (n = 264).

RESULTS

Airborne cat allergen levels were showing a similar variability throughout the whole study in all classes. Despite extensive measures in order to reduce allergen exposure, cat allergen levels were unaltered in the six classes after intervention. Allergen levels were not significantly lower in the established allergy prevention classes, compared with the other classes. Cat allergen levels differed, however, significantly between classes with few and many cat owners (P < 0.05).

CONCLUSIONS

We conclude that the recommended allergen avoidance measures used in this study did not reduce airborne cat allergen. It seems plausible that measures that fail to reduce allergen levels also fail to influence health status in allergic children but this remains to be shown.