Association between indoor fungi in Delhi homes and sensitization in children with respiratory allergy

A review on aero-allergen induced allergy in India

Allergic diseases such as bronchial asthma, rhinitis and eczema are an important public health issue globally in 21st century. Their prevalence and impact in India is high, in terms of total numbers of people affected. Due to diverse climate and lifestyle, the Indian population is exposed to a rich and varied range of aerobiological particles. In the last two decades in India, 83 pollens, 34 fungi, six dust mite and 19 insect species were reported as allergenic, often contributing to heavy allergenic exposure in indoor and outdoor environments. There are currently few practitioners who offer allergy diagnosis and treatment in India, but there is active basic and molecular research aiming to improve the health of allergic patients. This review explores the field of aero-allergy in India during the last two decades, with special emphasis on prevalence across various centres and relevant scientific advances such as genetic associations and new therapeutics. This review will be helpful for clinicians to select aero-allergens for sensitisation testing in patients suffering from symptoms in different regions of India, and to support patients undertaking prophylaxis of allergic symptoms in India according to local environmental conditions. This study also helps to define patient selection for allergy testing and the role of test results in guiding allergic disease management in the Indian context. Finally, we summarize genetic findings relevant to aero-allergy in India and discuss the development of novel therapeutics for investigation and management of aero-allergy in India.

Housing, health and energy: a characterisation of risks and priorities across Delhi's diverse settlements

Improved housing has the potential to advance health and contribute to the Sustainable Development Goals. Research examining housing, health and energy use in low-income countries is limited; understanding these connections is vital to inform interventions for healthy sustainable human settlements. This paper investigates the low-income setting of Delhi, where rapid urbanisation, a varied climate, high pollution levels, and a wide variation in housing quality could result in significant energy use and health risks. Drawing on approaches from health and the built environment and existing data and literature, a characterisation of energy use and health risks for Delhi's housing stock is completed. Four broad settlement types were used to classify Delhi housing and energy use calculations and health risk assessment were performed for each variant. Energy use is estimated to be nearly two times higher per household among planned housing compared with other settlement types. Health risks, however, are found to be largest within informal slum settlements, with important contributions from heat and particulate matter across all settlements. This paper highlights intervention priorities and outlines the need for extensive further research, particularly through data gathering, to establish evidence to accelerate achieving healthy, sustainable and equitable housing in Delhi.

Biological contaminants in the indoor air environment and their impacts on human health

Indoor air environment contains a complex mixture of biological contaminants such as bacteria, fungi, viruses, algae, insects, and their by-products such as endotoxins, mycotoxins, volatile organic compounds, etc. Biological contaminants have been categorized according to whether they are allergenic, infectious, capable of inducing toxic or inflammatory responses in human beings. At present, there is a lack of awareness about biological contamination in the indoor environment and their potential sources for the spreading of various infections. Therefore, this review article examines the association of biological contaminants with human health, and it will also provide in-depth knowledge of various biological contaminants present in different places such as residential areas, hospitals, offices, schools, etc. Moreover, qualitative and quantitative data of bio-contaminants in various indoor environments such as schools, hospitals, residential houses, etc. have also been derived from the recent literature survey.

Sensitization to Common Aeroallergens in the Atopic Population of West Bengal, India: An Investigation by Skin Prick Test

BACKGROUND

Aeroallergen sensitization is increasing worldwide. The optimal management of allergic disease requires the identification of the allergic sensitivities of the patient. Complete data of offending aeroallergens are scant from West Bengal, India. Hence, we employed a retrospective analysis of an atopic population of West Bengal to investigate the rate of sensitivity toward common aeroallergens including pollens, molds and house dust mites.

OBJECTIVES

The aim of the present study was to evaluate the profile of skin prick test (SPT) reactivity of an atopic population of eastern India.

METHODS

The prevalence aeroallergen sensitization was investigated by SPT along with a questionnaire survey of patients who visited the Allergy and Asthma Research Center of West Bengal, India, from June 2016 to May 2018. Patients were categorized according to the demographic (age, gender) and clinical aspects. Statistical tests were applied to differentiate between age and gender of the sufferers.

RESULTS

524 out of 605 patients exhibited a positive SPT response toward one or more aeroallergens tested. One-way ANOVA following Tukey's post hoc test reveals the age group of 15-40 years was more sensitized than that of < 15 years and no male-female discrimination was found using the paired t test. House dust mites, namely Dermatophagoides pteronyssinus and Dermatophagoides farinae, elicited most significant SPT results (80.34 and 84.92%, respectively) followed by Cocos (73.28%) and Azaridacta (57.25%) pollen. The most sensitive mold was Alternaria alternata (26.9%). Allergic rhinitis, bronchial asthma and atopic dermatitis were recorded as the common symptoms. Other influencing factors were family history, nature and season/time of onset and house conditions.

CONCLUSION

Following the increasing trend, house dust mite sensitization still held the dominance like in any other Indian population reported earlier. This study would pave the way to construct a standard and minimal SPT panel for the atopic patients of eastern India.

Spectrum of Allergens and Allergen Biology in India

The growing prevalence of allergy and asthma in India has become a major health concern with symptoms ranging from mild rhinitis to severe asthma and even life-threatening anaphylaxis. The "allergen repertoire" of this subcontinent is highly diverse due to the varied climate, flora, and food habits. The proper identification, purification, and molecular characterization of allergy-eliciting molecules are essential in order to facilitate an accurate diagnosis and to design immunotherapeutic vaccines. Although several reports on prevalent allergens are available, most of these studies were based on preliminary detection and identification of the allergens. Only a few of these allergen molecules have been characterized by recombinant technology and structural biology. The present review first describes the composition, distribution pattern, and natural sources of the predominant allergens in India along with the prevalence of sensitization to these allergens across the country. We go on to present a comprehensive report on the biochemical, immunological, and molecular information on the allergens reported so far from India. The review also covers the studies on allergy- related biosafety assessment of transgenic plants. Finally, we discuss the allergen-specific immunotherapy trials performed in India.

Air- and Dust-Borne Fungi in Indoor and Outdoor Home of Allergic Patients in a Dust-Storm-Affected Area

Despite the recent increases in fungi-induced allergic diseases, there is no report yet in the region of the Persian Gulf on concentration levels of fungi in relationship with health state. Therefore, our aim was to measure fungi prevalence as well as to evaluate the relationships between air- and dust-borne fungal genera and allergic diseases. A matched case-control study was carried out including 45 allergic cases and 45 age- and gender-matched controls for each individual. Indoor and outdoor dust and indoor air samples were collected from participant homes during May to October 2015. A Quick Take 30 Pump and sterile wet swab were used to determine fungal types and their amounts in the air (CFU/m³) and dust (CFU/100 cm²) samples, respectively. A significant reverse association was found between indoor dust-borne Alternaria and asthma (Odds ratio (OR) = 0.14, 95% CI = 0.02-0.86). Contrarily, increased levels of indoor air-borne Aspegillus fumigatus (OR = 2.00, 95% CI = 0.37-10.55) and Alternaria (OR = 3.00, 95% CI = 0.34-25.83) were correlated with asthma development. Also, correlation analysis showed a significant relation between indoor air-borne Penicillium levels and reactivity to skin prick test in asthmatic patients (p = 0.04). Our findings support the notion that fungal exposures can either cause or prevent the development of allergic diseases. Accordingly, appropriate measures should be taken for a better management of fungi-induced allergic diseases.

Aspergillus tubingensis: a major filamentous fungus found in the airways of patients with lung disease

The black Aspergillus group comprises A. niger and 18 other species, which are morphologically indistinguishable. Among this species subset, A. tubingensis, described in less than 30 human cases before 2014, is primarily isolated from ear, nose, and throat samples. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has emerged as a powerful technique to identify microbes in diagnostic settings. We applied this method to identify 1,720 filamentous fungi routinely isolated from clinical samples our laboratory over a two-year study period. Accordingly, we found 85 isolates of A. niger, 58 of A. tubingensis, and six other black Aspergillus (4 A. carbonarius and 2 A. japonicus). A. tubingensis was the fifth most frequent mold isolated in our mycology laboratory, primarily isolated from respiratory samples (40/58 isolates). In this study, we mainly aimed to describe the clinical pattern of Aspergillus tubingensisWe analyzed the clinical features of the patients in whom A. tubingensis had been isolated from 40 respiratory samples. Thirty patients suffered from cystic fibrosis, chronic obstructive pulmonary disease or other types of chronic respiratory failure. Strikingly, 20 patients were experiencing respiratory acute exacerbation at the time the sample was collected. Antifungal susceptibility testing of 36 A. tubingensis isolates showed lower amphotericin B MICs (P < 10(-4)) and higher itraconazole and voriconazole MICs (P < 10(-4) and P = .0331, respectively) compared with 36 A. niger isolates. Further studies are required to better establish the role that this fungus plays in human diseases, especially in the context of cystic fibrosis and chronic pulmonary diseases.

Assessment of allergenicity to fungal allergens of Rohtak city, Haryana, India

Fungal spores are known as one of the important bioparticles causing allergic manifestation in human beings. Hence, knowledge of season and prevalence of the airborne allergens to which the patients are exposed is a prerequisite for proper diagnosis and treatment of allergic disorders in hypersensitive individuals. Keeping this in view, aerial survey was performed in the atmosphere of Rohtak city for 2 consecutive years (March 2008-February 2010), using a volumetric petri plate sampler. A total of 45 fungal spore types were recorded during the survey period. In the present study, February-April and July-November were identified as the peak seasons for Rohtak city. Cladosporium was the main contributor to the total fungal load with 25.14% followed by Alternaria (18.05%), Aspergillus niger (7.66%), Curvularia (5.31%), and Epicoccum (5.29%). Fifteen dominant viable fungal spore types were represented in the form of a fungal calendar. An attempt has also been made to assess the allergenicity of some of the fungal types recorded from the atmosphere of Rohtak city. The magnitude of variations observed in markedly positive skin reactions (2+ and above) varied from 17.3 to 2.3%. Penicillium oxalicum showed a markedly positive reaction in maximum number of patients (26; 17.3%) followed by Rhizopus nigricans (23; 15.3%). ELISA was performed with the sera of patients showing markedly positive skin reactions and the sera were classified into four groups based on percent binding. The majority of the sera showed 0-15% binding to different antigenic extracts, while sera showing >60% binding were least in number. Greater than 30% binding was observed against antigens of Rhizopus nigricans, Epicoccum purpurascens, Penicillium oxalicum, Curvularia lunata, Aspergillus flavus, Candida albicans and Neurospora sitophila. The concordance between positive skin reaction and serum-specific IgE antibodies ranged from 16.7 to 69.2%.

Seasonal variation in skin sensitivity to aeroallergens

Purpose

We previously demonstrated seasonal variation in sensitization to aeroallergens in a small group of patients with exercise-induced asthma. This study was performed to confirm the relationship in a much larger population.

Methods

The charts of 1,891 patients who received allergy skin prick tests were reviewed retrospectively. The test results from subjects aged ≤60 years were compared between the groups classified according to the season when the patients received the tests (spring: March-May, summer: June-August, fall: September-November, winter: December-February). The data from 25 respiratory allergy patients who received the tests two or more times and showed a positive response at least once were analyzed longitudinally.

Results

The most prevalent among 29 tested aeroallergens were house dust mites (HDMs) Dermatophagoides pteronyssinus and D. farinae. The skin sensitization rates to D. pteronyssinus (23.2% vs. 32.1%, P=0.004) and D. farinae (22.2% vs. 30.2%, P=0.009) were significantly lower in the summer and higher in the fall (38.3% vs. 26.6% and 35.6% vs. 25.3%; P=0.001 respectively) than those in other seasons in patients with a respiratory allergy (n=1,102). The sensitization rates to weed pollens in the fall (13.9% vs. 8.3%, P=0.006) and to Aspergillus fumigatus in the winter (2.9% vs. 0.7%, P=0.005) were significantly higher. In patients with non-respiratory allergy such as urticaria/anaphylaxis (n=340), the D. farinae sensitization rate was significantly lower in the summer also but higher in the spring. The trend of the HDM sensitization rate being lower in the summer and higher in the fall was observed in the longitudinal study.

Conclusions

Skin sensitivity to aeroallergens such as HDMs, pollens, and molds demonstrates seasonal variation in respiratory allergy patients. Non-respiratory allergy patients also showed seasonal variation in sensitivity to aeroallergens, which might be related to the "priming" effect of allergens.

Allergic bronchopulmonary mycosis due to fungi other than Aspergillus: a global overview

Allergic bronchopulmonary mycosis (ABPM) is a hypersensitivity-mediated disease of worldwide distribution. We reviewed 143 reported global cases of ABPM due to fungi other than aspergilli. The commonest etiologic agent was Candida albicans, reported in 60% of the cases, followed by Bipolaris species (13%), Schizophyllum commune (11%), Curvularia species (8%), Pseudallescheria boydii species complex (3%) and rarely, Alternaria alternata, Fusarium vasinfectum, Penicillium species, Cladosporium cladosporioides, Stemphylium languinosum, Rhizopus oryzae, C. glabrata, Saccharomyces cerevisiae and Trichosporon beigelii. India accounted for about 47% of the globally reported cases of ABPM, attributed predominantly to C. albicans, followed by Japan (16%) where S. commune predominates, and the remaining one-third from the USA, Australia and Europe. Notably, bronchial asthma was present in only 32% of ABPM cases whereas its association with development of allergic bronchopulmonary aspergillosis (ABPA) is known to be much more frequent. The cases reviewed herein revealed a median IgE value threefold higher than that of ABPA, suggesting that the etiologic agents of ABPM incite a stronger immunological response than that by aspergilli in ABPA. ABPM is currently underdiagnosed, warranting comprehensive basic and clinical studies in order to elucidate its epidemiology and to devise a more effective therapy.