A nosocomial scabies outbreak originating from immunocompromised transplant patients in Turkey: Upholstery as a possible cause.

BACKGROUND: Inpatients with crusted scabies represent an important source of nosocomial transmission with consequent outbreaks among patients and healthcare workers. This study aimed to report the course of an institutional scabies outbreak, which progressed with infestation of immunosuppressed transplant patients, health care workers, and caregivers. METHODS: Patients diagnosed with scabies in a nosocomial outbreak in a 200-bed, tertiary hospital were included. Following a diagnosis of scabies in the index patient, strict contact isolation measures were implemented. During the outbreak, a root cause analysis (RCA) was carried out by an infection prevention and control team. RESULTS: Forty-two individuals were affected (7 patients, 25 health care workers, and 10 family members of the patients) during the outbreak consisting of three attacks. Index case was a multiple myeloma patient who received hematopoietic stem cell transplantation and presented with crusted scabies. A RCA suggested that upholstery could serve as a means of reservoir. All upholstery of the sofa and armchairs in patient rooms as well as in lounge areas were replaced by wipeable leather material. After the 19-week course of the outbreak, no additional cases of scabies have been observed until now. CONCLUSION: A high index of suspicion should be maintained, particularly in immunocompromised patients, in order to achieve rapid diagnosis of scabies and to implement institutional infection control measures. It should also be borne in mind that the transmission may occur through direct contact as well as fomites, such as upholstery.

Assessing the efficacy of a novel temperature and humidity control machine to minimize house dust mite allergen exposure and clinical symptoms in allergic rhinitis children sensitized to dust mites: a pilot study.

BACKGROUND: House dust mite avoidance is advised in dust mite sensitized patients to decrease the risk to develop allergic symptoms. Maintaining a relative humidity (RH) of less than 50% in households is recommended to prevent dust mite proliferation. OBJECTIVE: To investigate the efficacy of a novel temperature and humidity machine to control the level of dust mite allergens and total nasal symptom score (TNSS) in dust mite sensitized allergic rhinitis children. METHOD: Children (8-15 years) with dust mite sensitized persistent allergic rhinitis (AR) were enrolled. The temperature and humidity control machine was installed in the bedroom where the enrolled children stayed for 6 months. TNSS was assessed before and every month after machine set up and the level of dust mite allergen (Der p 1 and Der f 1) from the mattress were measured before and every 2 months after machine set up using enzyme-linked immunosorbent assay (ELISA). RESULTS: A total of 7 children were enrolled. Noticeable reduction of Der f 1 was observed as early as 2 months after installing the machine, but proper significant differences appeared 4 months after and remained low until the end of the experiment (p <0.05). Although no correlation was observed between TNSS and the level of dust mite allergens, there was a significant reduction in TNSS at 2 and 4 months (p <0.05) and 70% of the patients were able to stop using their intranasal corticosteroids by the end of the experiment. CONCLUSIONS: The level of house dust mite in mattresses was significantly reduced after using the temperature and humidity control machine. This machine may be used as an effective tool to control clinical symptoms of dust mite sensitized AR children.

Bed bug dermatitis, description of two cases in Rio de Janeiro, Brazil

Bed bugs are hematophagous insects which due to their morphological and biological characteristics are able to easily adapt themselves to human households. The authors describe two cases of dermatitis caused by bed bug bites in the city of Rio de Janeiro, Brazil. Patients presented linear lesions in the usual "breakfast, lunch and dinner" arrangement, suggesting this diagnosis. A visit to their dwellings showed infestation of insects identified as Cimex hemipterus. The knowledge of these insects by the dermatological community will contribute to an accurate diagnosis as well as subsidize the dissemination of information aiming for prevention.

Distribution features of biological hazardous pollutants in residential environments in Korea.

This research has been conducted continuously since 2009 as part of a cohort of studies examining relationships between asthma and genetic factors, dietary habits, and environmental factors. Based on data from environmental research on house dust mites and endotoxins, which are widely known as pollutants in bedding that cause asthma in pregnant women and children, this work was conducted to obtain basic data that can be used in future cohort studies that analyze links between distribution of biological hazards and physical features of residential environments. The detection rates of house dust mite allergens, Der p1 and Der f1, were 52.7 and 86.5%, respectively, indicating that Der f1 is a dominant species in domestic indoor environments. According to comparisons between concentrations of house dust mites and endotoxins in bedding of pregnant women and children, Der p1 and endotoxins showed significantly lower concentrations in bedding of pregnant women compared with those in bedding of children, whereas Der f1 showed no significant difference in concentration according to bedding.

Mite exposure in a Spanish Mediterranean region.

BACKGROUND: Knowledge of the domestic mite fauna and allergen levels is important for a correct diagnosis and treatment of mite allergy. Our objectives were to describe the domestic mite fauna in the region of Murcia, Spain, to quantify mite allergens in dust samples obtained from mattresses of this area and to assess the influence of geographical, climatic and dwelling factors. METHODS: Dust samples were collected in a transversal descriptive study from mattresses of 51 patients who went to the Allergology Service, and from mattress of 81 neighbours or family members of these patients. A questionnaire about home environment was filled in and obtained by all participants. Mite identification was done by light microscopy and allergen determinations (Der p 1 and Der f 1) by monoclonal antibodies. RESULTS: Sixteen mite species were identified in the 132 dust samples collected. The most frequent species were Dermatophagoides farinae (36% of the samples), Dermatophagoides pteronyssinus (32%) and Tyrophagus putrescentiae (5.3%). There were significant differences among climatic regions. The coastal sector had greater mite abundance, being D. pteronyssinus more frequent and abundant than D. farinae. In inland areas D. farinae was the predominant mite species. Allergen levels correlated with the concentration of Dermatophagoides, with higher levels detected in coastal regions. Average annual temperature was the main outdoor factor that correlated with higher mite concentrations. Indoor main predictor of higher levels of mites was the presence of obvious signs of humidity in the home. CONCLUSION: This study demonstrates the existence of a mite fauna dominated by D. pteronyssinus and D. farinae with a strong influence of climatic factors and residential characteristics.

Seasonal trends in house dust mite allergen in children's beds over a 7-year period.

BACKGROUND: House dust mite (HDM) allergy is closely linked to the expression of asthma and other allergic diseases. Understanding factors influencing variation in allergen may help in controlling allergic disease. The objective of this study was to investigate the effects of seasonal changes in climate, type of bed used in very early childhood and anti-mite interventions on HDM allergen concentration. METHODS: Participants were enrolled in a randomized-controlled trial of HDM avoidance. Der p 1 was measured in dust samples from children's beds on 13 occasions, from birth to age 5 years, between 1997 and 2004. Bed types were categorized as bassinette, cot or bed. The effects of study month, type of bed and intervention group on HDM allergen concentration were estimated by multiple linear regression. The relation between climatic variables and HDM allergen concentration was investigated using a polynomial distributed lag model. RESULTS: House dust mite allergen concentrations were initially low in cots and bassinettes in 1997/1998, peaked in bassinettes and beds between 1999 and 2001 and then slowly declined during the period 2002/2004. Seasonal fluctuations occurred with minima in summer and two- to threefold higher maxima during late autumn. Allergen peaks were correlated with relative humidity peaks 2 months previously. Seasonal changes in allergen were not affected by the HDM avoidance intervention. CONCLUSIONS: House dust mite allergen concentrations in Sydney beds fluctuate approximately two- to threefold on an annual cycle, partly determined by relative humidity, with peaks in late autumn and minima in summer. Fluctuations of this magnitude might be sufficient to influence asthma symptoms.

Effectiveness of house dust mite acaricide tri-n-butyl tin maleate on carpets, fabrics and mattress foam: a standardization of methodology

O objetivo do presente estudo foi verificar a eficácia do acaricida maleato de estanho tri-n-butílico, aplicado industrialmente em amostras de carpetes, tecidos de revestimentos de móveis e de calçados, assim como de espumas de colchão. Aproximadamente 100 ácaros adultos da espécie Dermatophagoides pteronyssinus foram inoculados em placa de Petri contendo a amostra (pedaço de colchão, tecido ou carpete), tratada com o produto acaricida, coletados aleatoriamente. Foi acrescentado sobre a amostra, meio de cultivo para a manutenção dos ácaros. Cada placa foi examinada após 1, 2, 3, 7 e 30 dias de incubação a 25 ºC e 75% de U.R.A. (umidade relativa do ar), sob microscópio estereoscópico com 40X de aumento. O acaricida maleato de estanho tri-n-butílico apresentou 100% de eficácia acaricida após 30 dias da aplicação, em condições ótimas para a manutenção dos ácaros.

House dust mite allergen levels in Chiang Mai homes.

The quantitative assays for house dust mite (HDM) allergens provide a valid index of exposure and can be used for risk evaluation. We assessed group I HDM allergen levels in mattress and living room floor dust from 35 Chiang Mai homes and identified factors associated with high allergen levels. One-third of mattress and living room floor dust had group I HDM allergen levels of between 2-10 microg/g. Two-thirds of mattress dust and a small amount of living room floor dust had group I HDM allergen levels of over 10 microg/g. The geometric means of Der p I, Der f I and total group I allergens in mattress and living room floor dust were 8.61, 2.88, and 15.81 microg/g and 1.61, 0.27 and 2.43 microg/g, respectively. Mattresses made of kapok and rugs kept in the living room were associated with high group I allergen levels.

House dust mite allergen in US beds: results from the First National Survey of Lead and Allergens in Housing.

BACKGROUND: Although exposure to house dust mite allergen is a major risk factor for allergic sensitization and asthma, nationwide estimates of dust mite allergen levels in US homes have not been reported. OBJECTIVE: The purpose of this study was to estimate the prevalence of dust mite allergen in beds of US homes and to identify predictors of dust mite allergen concentration. METHODS: Data were obtained from the first National Survey of Lead and Allergens in Housing, a cross-sectional survey of 831 permanently occupied noninstitutional housing units that permitted resident children. Dust mite allergen concentration (Der f 1 plus Der p 1) was determined from a dust sample collected from a bed. The percentages of homes with concentrations at or greater than detection, 2.0 microg/g bed dust, and 10.0 microg/g bed dust were estimated. Independent predictors of allergen concentration were assessed with multivariable linear regression. RESULTS: The percentages of US homes with dust mite allergen concentrations at or greater than detection, 2.0 microg/g, and 10.0 microg/g were 84.2% (SE, 1.73), 46.2% (SE, 2.0), and 24.2% (SE, 2.1), respectively. Independent predictors of higher levels were older homes, non-West census regions, single-family homes, no resident children, lower household income, heating sources other than forced air, musty or mildew odor, and higher bedroom humidity. CONCLUSION: Most US homes have detectable levels of dust mite allergen in a bed. Levels previously associated with allergic sensitization and asthma are common in US bedrooms. Predictors can be used to identify conditions under which homes are more likely to have increased dust mite allergen levels.