Respiratory sensitization to insect allergens: Species, components and clinical symptoms.

Airborne insect particles have been identified as an important cause of respiratory allergies, including allergic asthma and rhinitis. In the literature, the significance of respiratory exposure to insect particles as a cause of occupational allergy has been well-documented. Indeed, many cases of occupational allergy have been reported including allergy to the larvae of flies and moths in anglers and occupationally exposed workers, to grain pests in bakers or other workers handling grains, and to crickets and/or locusts in researchers and workers in aquaculture companies. Furthermore, the prevalence of sensitization to insect allergens is considerably high among patients with asthma and/or rhinitis who are not occupationally exposed to insects, suggesting the clinical relevance of exposure to insects in indoor and outdoor environmental non-occupational settings. Exposure to cockroaches, a well-studied indoor insect, is associated with cockroach sensitization and the development and exacerbation of asthma. Booklice, another common indoor insect, were recently identified as a significant sensitizer of asthmatic patients in Japan and India, and potentially of asthma patients living in warm and humid climates around the world. Lip b 1 was identified as an allergenic protein contributing to the species-specific sensitization to booklice. Moths are considered a significant seasonal outdoor allergen and their allergens are considered to have the highest sensitization rate among Japanese patients. However, other than cockroaches, allergenic insect proteins contributing to sensitization have not been fully characterized to date.

Allatostatin A-like immunoreactivity in the nervous system and gut of the larval midge Chironomus riparius: modulation of hindgut motility, rectal K+ transport and implications for exposure to salinity.

Evidence for the presence of allatostatin (AST) A-like neuropeptides in the larval midge Chironomus riparius is reported. Immunohistochemical studies on the nervous system and gut revealed the presence of AST A-like immunoreactive (AST-IR) cells and processes. The nerve cord contained AST-IR processes that originated from cells in the brain and travelled the length of nerve cord to the terminal ganglion. Within each ganglion, these processes gave rise to varicosities, suggesting that they formed synapses with neurons in the ganglia. Endocrine cells containing AST-IR were present in three regions of the midgut: near the attachment of the Malpighian tubules, between the anterior and posterior midgut, and in the vicinity of the gastric caecae. The terminal ganglion also contained four AST-IR cells that gave rise to axons that projected onto the hindgut and posterior midgut. Application of a cockroach AST to the semi-isolated hindgut of larval C. riparius led to dose-dependent inhibition of muscle contractions with an EC50 of ~10 nmol l(-1) and a decrease in rectal K(+) reabsorption resulting from reduced rectal Na(+)/K(+)-ATPase and vacuolar type H(+)-ATPase activities. The results suggest the presence of endogenous AST-like neuropeptides in larval C. riparius, where these factors play a role in the function of the gut. Furthermore, regulation of ion reabsorption by ASTs at the rectum could serve as an ideal mechanism of ion regulation in the face of abrupt and acute elevated salt levels.

Chironomid midges as allergens: evidence from two species from West Bengal, Kolkata, India.

BACKGROUND & OBJECTIVES: Arthropods of different taxonomic identity including chironomid midges are known to induce allergic response in humans. The present study was done to access two common chironomid species Chironomus circumdatus and Polypedilum nubifer for their sensitizing potential as an allergen in atopic patients and controls. METHODS: Following preparation of allergenic extracts of the two chironomid species separately, 198 atopic patients attending an allergy clinic and 50 age matched controls were tested along with a routine panel of allergens to assess sensitization. RESULTS: The skin prick test (SPT) results revealed that 189 of the 198 patients (95.4%) demonstrated sensitization to both the chironomid species. Higher levels of total IgE was observed in atopic subjects than in the control group. INTERPRETATION & CONCLUSIONS: The results suggest that the chironomid midges Chironomus circumdatus and Polypedilum nubifer can elicit sensitization in humans. A potential risk for allergic reactions by susceptible individuals exists due to these chironomid species, owing to their abundance and chances of contact with human beings. Further studies may be initiated to characterize the nature of the allergens and to assess their clinical relevance.

Chironomid midge sensitization in sewage workers: case study.

Non-biting chironomid midges (Diptera: Chironomidae) may cause sensitization and allergic reactions in humans and have recently been identified as a potential health problem in Swedish municipal sewage treatment plants. To investigate, on a pilot scale, the allergenic potential of chironomids in sewage workers, all workers (n = 8) at a sewage treatment plant and local controls (n = 16) completed a symptom questionnaire, underwent measurement of the fraction of nitric oxide in exhaled air, spirometry, and provided serum samples for the determination of atopy status and the prevalence of specific immunoglobulin E (IgE) antibodies against Chironomus thummi (Chi t) using a commercial fluorescence enzyme immunoassay (FEIA). Three sewage workers (38%) but no controls (0%) were FEIA positive for C. thummi-specific IgE antibodies (P < 0.05). No other health-related findings were significantly different between the groups. The study suggested that occupational exposure to Chironomids may cause sensitization with circulating IgE-antibodies in sewage workers.

Occupational allergy to aquarium fish food: red midge larva, freshwater shrimp, and earthworm. A clinical and immunological study.

BACKGROUND: Chironomids seem to be the main cause of occupational allergy to aquarium fish food. OBJECTIVE: The aim of this study was to investigate the pattern of occupational sensitization to 3 different arthropod species used as components of aquarium fish food. METHODS: The study sample comprised 8 workers from a fish food packing department. The control group comprised 40 atopic patients (20 of whom were allergic to mites). We performed prick tests with extracts of red midge larva (Chironomus thummi), freshwater shrimp (Gammarus species), earthworm (Tubifex species), and other arthropod species and a battery of common inhalant allergens. We measured peak expiratory flow rate (PEFR) and specific immunoglobulin (Ig) E and performed a methacholine challenge test, nasal challenge test, and immunoblotting. Cross-reactivity analyses were completed using immunoblotting and CAP inhibition. RESULTS: Prick test results were positive to red midge larvae in 7 patients (87.5%), Gammarus in 5 (62.5%), Tubifex in 3 (37.5%), and mites in 6 (75%). In the mite-allergic controls, 30% had positive prick test results to red midge larvae. PEFR decreased > or = 20% during the packing process in all patients, and in 1 patient it indicated a dual asthmatic response. Methacholine challenge test results were positive in all participants. Nasal challenge tests were performed in 4 patients, and the results were positive. Specific IgE to red midge larvae was detected in 62.5%, Gammarus in 50%, and Tubifex in 16%. Bands of approximately 14-15 kDa and 31 kDa were observed in Gammarus and red midge larvae extracts. Cross-reactivity assays demonstrated that Gammarus totally inhibited red midge larvae, while Tubifex did so partially. Dermatophagoides pteronyssinus showed very low inhibitory capacity. CONCLUSIONS: Aquarium fish food arthropods are potent allergens with an elevated prevalence of sensitization and variable degree of crossreactivity. This is the first report of occupational allergy to Tubifex. More data are necessary to identify and characterize the responsible allergens.

Impact of tributyltin on immune response and life history traits of Chironomus riparius: single and multigeneration effects and recovery from pollution.

Chironomids play an important role in the detritus cycle and as a component in brackish- and freshwater benthic and terrestrial food webs. If TBT is present in their environment, then they may accumulate tributyltin (TBT) during their juvenile period, which negatively affects many of their life history characteristics. The aim of this experiment is to test the effects of three TBT sediment concentrations (nominal 30, 90, and 180 µg/kg) on life history traits (development time, survival, fecundity, and weight) and immune response (number of hemocytes and phenoloxidase activity) of the nonbiting midge, Chironomus riparius. These responses were recorded immediately after one generation of TBT exposure, and in the long run during five consecutive generations. We also assessed recovery from pollution after four generations of TBT exposure. In a single generation, TBT affected all measured parameters, except phenoloxidase activity, when compared to the control. Long-term-effects of TBT lead to extinction of all treatments after the fifth generation. Again, all measured variables significantly differ from the control, although TBT had varying effects on the measured variables. Most of the effects of TBT on population viability were not evident during recovery, once TBT was removed from the sediment. The effect of previous TBT contamination was observed only in delayed larval development, suggesting that TBT has only limited maternal/epigenetic effects on individual condition. However, altered schedules in the life-cycle can have unexpected ecological impacts. TBT decreases the viability of Chironomus riparius and the effect will become stronger if exposure to TBT continues for many generations. Yet, the harmful effect of TBT disappears quickly as the TBT is removed from the environment.

Allergy to chironomid larvae (red migde larvae) in non professional handlers of fish food.

UNLABELLED: Chironomids are insects which inhabit wetlands. In countries such as Sudan, The United States. Egypt and Japan they are the cause of serious environmental allergy. In Europe, and particularly in Spain, allergy to Chironomids is infrequent and has only been described in patients who handle Chironomid larvae which form part of certain fish foods. MATERIALS AND METHODS: We report a case of hypersensitivity to the Chironomid Midge (Chironomus thummi thummi) in a 23-year-old patient who on two occasions, after being in contact with fishfood, suffered rash, rhinoconjunctivitis, dyspnea and dysphagia. A Prick test was carried out with the habitual pneumoallergens, Chironomid Midge extract (PBS: 1.3 mg/ml), Common Mosquito (Culex pipiens), Squid, Mussel, Prawn and Anisakis. Conjunctival provocation was also carried out with Chironomid Midge extract; detection of specific IgE for Chironomid Midge, Common Mosquito (Aedes comunis), Mussel, Squid, Shrimp, Anisakis, house dust and house mites by means of the CAP technique; detection of IgE by means of ELISA in response to Chironomid Midge, Aedes mosquito, Squid, Prawn, Mussel and Anisakis; ELISA-inhibition and Immunoblott-inhibition. RESULTS: The positive results of the cutaneous tests, the detection of specific IgE and conjunctival provocation confirmed the existence of an IgE-mediated mechanism. In our patient, the in vitro techniques demonstrated cross reactivity with the Common Mosquito. CONCLUSIONS: We report on a patient with a case history of rhinoconjunctivitis, rash, dyspnea, and dysphagia after handling fish food. The etiological agent was the Chironomid larvae. The sensitization of our patient has been demonstrated by means of in vivo and in vitro techniques.

Molecular cloning and characterization of tropomyosin, a major allergen of Chironomus kiiensis, a dominant species of nonbiting midges in Korea.

Chironomids are widely and abundantly distributed in the vicinity of standing waters. Larvae of Chironomus and some other genera are known to contain hemoglobins, which have been described as a major allergen, and the adults that have no hemoglobins also have been reported to contain allergens. In this study, we tried to establish the role of chironomid allergy and characterize the allergen of Chironomus kiiensis adults. Skin tests using C. kiiensis adult extracts were performed on patients with allergic symptoms. A cDNA library of C. kiiensis adults was screened with C. kiiensis immune mouse sera to identify allergens, and results were confirmed using skin test-positive human sera. Recombinant allergen was expressed in Escherichia coli and purified by affinity chromatography using nickel-nitrilotriacetic acid agarose to investigate its allergenic properties. Out of 275 allergic patients 14.2% showed a positive reaction to C. kiiensis adult crude extracts in the skin test. The tropomyosin was cloned by immunoscreening and expressed in Escherichia coli. C. kiiensis tropomyosin has a high homology at the amino acid level with tropomyosins which were previously known to be allergens in various arthropods (Periplaneta americana, 86.3%; Panulirus stimpson, 78.9%; Dermatophagoides pteronyssinus, 76.5%). Specific immunoglobulin E antibodies reacting to recombinant tropomyosin were detected in 17 (81%) of 21 patients whose skin test results were positive. Cross-reactivity against house dust mites and other insects was noticed with mouse anti-recombinant tropomyosin immune serum. C. kiiensis adults were shown to be an important source of inhalant allergens in Korea. Molecular cloning of C. kiiensis tropomyosin was performed and IgE reactivity was demonstrated using skin test-positive human sera. Recombinant tropomyosin will be useful for further studies or clinical applications.

[Nationwide investigation of insect allergy in patients with allergic rhinitis].

To clarify the role of insects as allergens in allergic rhinitis (AR), specific IgE antibodies (sIgE) to the moth, midge, and cockroach together with 10 other allergens were measured using sera from 560 AR patients, who visited 20 otolaryngological clinics nationwide from Hokkaido to Kyushu. Nasal challenge tests were also conducted with allergen disks of these 3 insects in 65 AR patients. Frequencies of sIgE positive to the moth, midge, and cockroach were 32.5%, 16.1%, and 13.4%. Frequencies of sIgE positive to these insects were not affected by patients' residential location, age, medication, or association with bronchial asthma. The prevalence of patients with positive nasal challenge increased depending on the RAST class to the insects. Among the patients whose RAST class were 3 and 4, nasal challenges with cockroach or moth extracts were positive in 55.6% or 61.5%. A strong correlation of sIgE titers was observed between the moth and midge, but the correlation between the cockroach and moth, and between the cockroach and midge were weak. No correlation of sIgE titers was found between house dust mites and these 3 insects. These results show that the moth, midge, and cockroach are inhalant allergens causing allergic rhinitis in Japan.

Chironomid potent allergens causing respiratory allergy in children.

Generally speaking, chironomids contain potent inhalant allergens. The skin prick tests with chironomid crude extract (Chironomus (C.) calipterus) were positive in 20 out of 25 children with respiratory allergy. The skin prick tests with house dust mite crude extract (Dermatophagoides pteronyssinus) were positive in 3 of these 20 chironomoid positive skin tests. Chironomid-specific IgE-ELISA were demonstrated in the sera of 17 (85%) of the chironomid skin positive patients. These 17 patients gave negative skin prick test to house dust mite crude extract. It is concluded that chironomid allergens should be considered when dealing with human respiratory allergy caused by arthropods.

Identification of Chironomus kiiensis allergens, a dominant species of non-biting midges in Korea.

Non-biting midges are known to contain potent inhalant allergens. IgE antibody responses to the crude extract of Chironomus kiiensis adults, a dominant chironomid species in Korea, were examined. With the IgE-ELISA or passive cutaneous anaphylaxis reactions, increased levels of chironomid-specific IgE were detected in the skin test positive human sera, or immunized BALB/c mouse sera with the crude extract adsorbed to alum. IgE-immunoblot analysis showed major IgE-reacting protein band patterns, which reacted with more than 50% of the skin test positive human sera, at 110, 80, 73, 46, 40, 37, 34, and 31 kDa. The reactive band patterns were largely similar between skin test positive humans and immune BALB/c mice. However, the bands of 55, 31, 27, 26, 24, and 23 kDa were found only in sensitized humans, but not in immunized mice.

Patterns of immunoglobulin E sensitization to chironomids in exposed and unexposed subjects.

We present our study of four patients with occupational type I allergy to red midge larvae (group 1) who we compared with seven individuals also sensitized to red midge larvae but who had not apparently been exposed to them (group 2). All patients showed elevated specific IgE against Chironomus thummi, and positive skin prick tests (SPT) and provocation tests with red midge larvae. We carried out SPT with Dermatophagoides pteronyssinus, Acarus siro, shrimp, cockroach and common mosquito (Culex pipiens) and specific serum IgE was also determined. The red midge larvae wheal size was significantly larger in group 1 (x = 149.2 mm2) than in group 2 (x = 18 mm2). Significant differences between levels of IgE anti-C. thummi were also found in group 1 (x = 52.12 kU/l) and in group 2 (x = 1.5 kU/l). The patients in group 2 had high levels of specific IgE against other allergens (D. pteronyssinus, shrimp and/or common mosquito) and had positive SPTs with these allergens, while the patients in group 1 were only sensitized to chironomids. The IgE-immunoblotting profile was quite different in both groups. The patients in group 1 seemed to have IgE against Chi t 1, the main Chironomus allergen, while the patients in group 2 had IgE against several protein bands in Chironomus, mosquito, shrimp and D. pteronyssinus extracts, some of them with equivalent molecular weights. We believe that the patients in group 2 were sensitized to Chironomus as a result of cross-reactivity with other insect or crustacean species.