Occupational exposure to allergenic mites among workers of the Silesian Zoo

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1 OCCUPATIONAL EXPOSURE TO ALLERGENIC MITES 375 BIOLOGICAL LETT. 2006, 43(2): Available online at Occupational exposure to allergenic mites among workers of the Silesian Zoo PIOTR SZILMAN 1, EWA SZILMAN 1, MAGDALENA SZILMAN 2, EL BIETA MESZYÑSKA 2, HANNA MANIURKA 1, KRZYSZTOF SOLARZ 1 and ALEKSANDER L. SIEROÑ 3 1 Department of Parasitology, Medical University of Silesia, Sosnowiec, Poland, szilpio@slam.katowice.pl; 2 Department of Toxicology, Medical University of Silesia, Sosnowiec, Poland; 3 Department of General and Molecular Biology and Genetics, Medical University of Silesia, Katowice, Poland (Received on 18 January 2006, Accepted on 30 September 2006) Abstract: The study was carried out from April 2004 to March 2005, when 65 samples of dust, litter, debris and residues from the Silesian Zoo were examined for the presence of mites. Mites were found in all the samples; a total of 5, 315 mites were isolated and 26 species of astigmatid mites were identified. These mites constituted 84% of the total catch. Tyrophagus perniciosus was a dominant (57.9%), followed by T. putrescentiae (7.7%), Acarus farris (5%) and T. longior (4.9%). Dermatophagoides pteronyssinus was found for the first time in this environment. Whole-protein extracts were made from 6 cultured mite species: Dermatophagoides farinae, D. pteronyssinus, T. putrescentiae, Acarus siro, Lepidoglyphus destructor and Glycyphagus domesticus. The proteins were fractionated by SDS-PAGE and identified by Western blot. Zoo workers antibodies against particular antigens were identified in the serum IgE fraction by using an anti-human IgE monoclonal antibody. The results showed that 50% of tested sera reacted specifically with protein fractions of about 60 kda in extracts from T. putrescentiae; 34.2% of the workers sera recognized allergens of about 50 kda from whole mite extracts of L. destructor; and 34.2% of tested sera reacted specifically with new antigens of about 70 kda in extracts from A. siro. Thus the results revealed the occurrence of allergenic mites in the examined places in the Silesian Zoo and the strong and specific immune responses of zoo workers to various mite allergens. Key words: allergenic mites, acarofauna, storage mites, house dust mites, exposure, mite allergen, mite antigen, sensitization, occupational biohazards INTRODUCTION In past years the significance of atopic allergies has increased in industrialised countries. House dust mites from the family Pyroglyphidae (Acari: Acaridida) are recognized as the most important risk factor causing allergies in indoor environments (ARLIAN 2002). The storage mites are also sources of clinically important allergens and they cause occupational allergy known as allergy to storage mites in farmers,

2 376 P. Szilman et al. grain-storage workers, bakers, pastry-cooks, shopkeepers, millers, store-keepers, cheese-makers, horseriders, dockers, transport workers, upholsterers, miners and some other occupational categories. Exposure to indoor allergens, especially dust mites, has been recognized as a risk factor for sensitization and allergy symptoms that in extreme conditions could develop into asthma (HAGE-HAMSTEN & JOHANSSON 1998, ARLIAN 2002). The aim of this work was: (1) to study the frequency, dominance structure and species composition of allergenic acarofauna as occupational biohazards in cages, terrariums and runs of animals in a zoo, and thus to assess the exposure of zoo workers to allergenic mites; and (2) to determine specific antigens responsible for mite allergy in these workers. MATERIALS AND METHODS The study was carried out from April 2004 until March During this period, 65 samples of dust, litter, debris and residues from cages and runs of mammals, birds and reptilians in the Silesian Zoo in Katowice (southwestern Poland), were examined for the presence of mites, especially the allergenic taxa. Mites were extracted by using the Berlese method and preserved in 70% ethanol. For identification the mites were mounted in Hoyer s medium on microscope slides. Whole protein extracts were made from 6 cultured mite species, i.e. Dermatophagoides farinae Hughes, 1961, D. pteronyssinus (Trouessart, 1897), Tyrophagus putrescentiae (Schrank, 1781), Acarus siro L., 1758, Lepidoglyphus destructor (Schrank, 1781), and Glycyphagus domesticus (De Geer, 1778). The proteins were fractionated by SDS-PAGE and identified by Western blot. Blood samples were collected from all 38 zoo workers who cared for the animals. The workers antibodies against particular antigens were identified in serum IgE fraction by using the antihuman IgE monoclonal antibody (LAEMMLI 1970, TOWBIN et al. 1979). RESULTS AND DISCUSSION Mites were found in all analysed samples from the examined places in the zoo. A total of mites were isolated, from which 48.5% were found in samples collected in spring, whereas only 19.4% in summer and 25.05% in autumn. The remaining 7.05% of the total mite population was collected in winter. The majority of mites (62.9%) were harvested from aviaries of parrots. A total of 26 species of astigmatid mites were identified as belonging to 5 families: Acaridae, Glycyphagidae, Chortoglyphidae, Anoetidae and Pyroglyphidae. Generally, the mites of the order Astigmata constituted 84.0% of the total catch. Among them Tyrophagus perniciosus Zachwatkin, 1941 was a dominant (57.9% of the total catch), followed by T. putrescentiae (7.7%), Acarus farris (Oudemans, 1905) (5.0%) and T. longior (Gervais, 1844) (4.9%). Dermatophagoides pteronyssinus, the house dust mite, was for the first time found in this environment (SOLARZ et al. 2004). This mite (0.23% of the total catch) was associated with parrots and mammals (Table 1). Western blot analysis revealed differences in reactivity of sera from workers to fractionated mite antigens (Table 2; Fig. 1). The inhibition results are summarized in Table 2. This table shows all mite antigens and allergen components identified in

3 OCCUPATIONAL EXPOSURE TO ALLERGENIC MITES 377 Table 1. Taxonomic composition, dominance structure and frequency of mites found in samples from the examined places in the Silesian Zoo Mite taxa No. of mites Dominance % of all mites No. of samples Frequency % of all samples Mean no. of mites per sample Acarus siro Acarus farris Acarus immobilis Tyrophagus longior Tyrophagus neiswanderi Tyrophagus palmarum Tyrophagus perniciosus Tyrophagus putrescentiae Tyrophagus similis Caloglyphus oudemansi Acarotalpa fossor Paulacarellus sp Viedebanttia sp Lepidoglyphus destructor Lepidoglyphus fustifer Lepidoglyphus michaeli Glycyphagus domesticus Ctenoglyphus canestrini Ctenoglyphus plumiger Dermatophagoides farinae Dermatophagoides pteronyssinus Hirstia passericola Onychalges longitarsus Chortoglyphus arcuatus Histiostoma feroniarum Histiostoma sapromyzarum Anoetidae (hypopi) Oribatida Cheyletidae Bdellidae Tetranychidae Tarsonemidae Bryobinae Cunaxidae Tydeidae Other Actinedida Pygmaephoridae Pyemotidae Ixodes hexagonus (Ixodida: Ixodidae) Gamasida TOTAL

4 378 P. Szilman et al. Fig. 1. The IgE responses of 12 subjects (workers of the Silesian ZOO) against mite body proteins of Tyrophagus putrescentiae (T.p.), Dermatophagoides pteronyssinus (D.p.), D. farinae (D.f.), Acarus siro (A.s.), Lepidoglyphus destructor (L.d.) and Glycyphagus domesticus (G.d.) representative immunoblots (few bands are unique to these mite species). KS calibrated Molecular Weights of Kaleidoscope Standards extracts from the examined species of mites and the number of sera that recognized particular antigens in these extracts. The results revealed that 19 out of 38 tested sera (50%) reacted specifically with a new antigen identified as protein fractions of about 60 kda in extracts from T. putrescentiae. A total of 16 out of 38 sera (42.1%) from workers positive to skin tests showed specific reactivity with major allergens isolated from extracts of T. putrescentiae, known also as Tyr p 2 (Table 2), whereas a new antigen, a protein fraction of about kda, was bound by 15/38 (39.5%) of the examined sera. About 34.2% of the workers sera (13/38) detected allergens of about 50 kda from whole mite extracts of L. destructor (Table 2). Moreover, the results revealed that 13 out of 38 tested sera (34.2%) reacted specifically with new antigens, identified as protein fractions of about 70 kda, in extracts from A. siro. Half of the workers sera (19/38) recognized allergens of about 110 kda (Table 2). The most important IgE-binding components in the mites detected on immunoblots by sera of 12 workers are presented in Fig. 1. It must be stressed that cages and runs of various mammals, aviaries of parrots, and terrariums of serpents are major sources of some allergenic mites, especially T. putrescentiae, T. longior, D. pteronyssinus, L. destructor, G. domesticus, A. siro and D. farinae, which can cause allergies in workers (KRONQVIST et al. 2000, AR- LIAN 2002). When assessing mite allergen reactions by using a mixture of mite proteins, the results of skin test are not satisfactory for determining the antigen causing a patient s allergy. New antigens identified as protein fractions of about 50 kda have been revealed in extracts from L. destructor and A. siro (ARLIAN 2002, SZILMAN et al a, b, YADAV et al. 2006, Also, new classes of immunizing proteins of about and 60 kda have been identified in the protein extracts from T. putrescentiae (ARLIAN 2002, SZILMAN et al. 2004a, b, KONDREDDI

5 OCCUPATIONAL EXPOSURE TO ALLERGENIC MITES 379 Table 2. Numbers of zoo workers sensitive to various mite antigens Mite species Antigen Molecular weight (kda) No. of sensitive workers Dermatophagoides farinae Dermatophagoides pteronyssinus Tyrophagus putrescentiae Lepidoglyphus destructor Acarus siro Der f 1 25 Der f 2 14 Der f Der f Der f Der f Der p 1 25 Der p 2 14 Der p 4 60 Der p Der p Tyr p 2 16 Tyr p 24 Tyr p Tyr p 50 Tyr p 60 Lep d 2 15 Lep d 7 24 Lep d Lep d 50 Aca s 70 Aca s et al. 2006) reacting with IgE from workers showing allergy to various mite extracts. All workers showed specific reactivity with various antigens isolated from the protein extracts of examined allergenic mites. In summary, the present results reveal the occurrence of allergenic mites in the examined places in the Silesian Zoo and the immune responses to various mite allergens in workers. Thus they should all be regarded as a potential source of mite allergens in this environment. REFERENCES ARLIAN L. G Arthropod allergens and human health. Annu. Rev. Entomol. 47: HAGE-HAMSTEN M., JOHANSSON E. VAN Clinical and immunologic aspects of storage mite allergy. Allergy 53 (Suppl. 48): LAEMMLI U. K Cleavage of structural proteins during assembly of the head of the bacteriophage T4. Nature 227: KONDREDDI P. K., ELDER B. L., MORGAN M. S., VYSZENSKI-MOHER D. L., ARLIAN L. G Importance of sensitization to Tyrophagus putrescentiae in the United States. Ann. Allergy, Asthma Immunol. 96:

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