Carpet Type Research Articles

Persistence of two coronaviruses and efficacy of steam vapor disinfection on two types of carpet

BackgroundCoronaviruses, a group of highly transmissible and potentially pathogenic viruses, can be transmitted indirectly to humans via fomites. To date, no study has investigated their persistence on carpet fibers. Establishing persistence is essential before testing the efficacy of a disinfectant.MethodsThe persistence of BCoV and HCoV OC43 on polyethylene terephthalate (PET) and nylon carpet was first determined using infectivity and RT-qPCR assays. Then, the disinfectant efficacy of steam vapor was evaluated against both coronaviruses on nylon carpet.ResultsImmediately after inoculation of carpet coupons, 32.50% of BCoV and 3.87% of HCoV OC43 were recovered from PET carpet, compared to 34.86% of BCoV and 24.37% of HCoV OC43 recovered from nylon carpet. After incubation at room temperature for 1 h, BCoV and HCoV OC43 showed a 3.6 and > 2.8 log10 TCID50 reduction on PET carpet, and a 0.6 and 1.8 log10 TCID50 reduction on nylon carpet. Based on first-order decay kinetics, the whole gRNA of BCoV and HCoV OC43 were stable with k values of 1.19 and 0.67 h− 1 on PET carpet and 0.86 and 0.27 h− 1 on nylon carpet, respectively. A 15-s steam vapor treatment achieved a > 3.0 log10 TCID50 reduction of BCoV and > 3.2 log10 TCID50 reduction of HCoV OC43 on nylon carpet.ConclusionBCoV was more resistant to desiccation on both carpet types than HCoV OC43. Both viruses lost infectivity quicker on PET carpet than on nylon carpet. Steam vapor inactivated both coronaviruses on nylon carpet within 15 s.

Efficacy of three EPA-registered antimicrobials and steam against two human norovirus surrogates on nylon carpets with two backing types.

Carpet cleaning guidelines currently do not include the use of an antimicrobial, except after a bodily fluid event. To address this gap, we compared the efficacy of three antimicrobials-two hydrogen peroxide-based (H2O2) products (A and B) and one chlorine-based product (C)-and a steam treatment against two norovirus surrogates, specifically feline calicivirus (FCV) and Tulane virus (TuV). These tests were performed on nylon carpets with either water-permeable or waterproof backing types. The effect of repeated antimicrobial use on carpet properties was also evaluated. For a carpet with water-permeable backing, products A, B, and C achieved a 0.8, 3.1, and 0.9 log10 PFU/coupon reduction of FCV and 0.3, 2.5, and 0.4 log10 TCID50/coupon reduction of TuV, respectively, following a 30 min contact time. For carpet with waterproof backing, only product B achieved a 5.0 log10 PFU/coupon reduction of FCV and >3.0 log10 TCID50/coupon reduction of TuV, whereas products A and C achieved a 2.4 and 1.6 log10 PFU/coupon reduction of FCV and a 1.2 and 1.2 log10 TCID50/coupon reduction of TuV, respectively. Steam treatment achieved a ≥ 5.2 log10 PFU/coupon reduction of FCV and a > 3.2 log10 TCID50/coupon reduction of TuV in 15 seconds on the carpet with both backing types. The repeated use of products A and B decreased the tensile strength of the carpet backing, while use of product B resulted in cracks on carpet fibers. Overall, steam treatment for 15 seconds was efficacious on both carpet types, but only product B achieved efficacy after a 30-minute exposure on the carpet with waterproof backing.IMPORTANCECarpets are common in long-term care facilities, despite its potential as a vehicle for transmission of agents associated with healthcare-associated infections, including human norovirus (NoV). Presently, our understanding of carpet disinfection is limited; hence, there are no commercial antimicrobials against norovirus available for use on carpets. Our findings showed that steam treatment, which minimally affected the properties of carpet fibers and backing, was more efficacious against human norovirus surrogates on carpets compared to the three chemical antimicrobials tested. Additionally, the two surrogates were more sensitive to chemical antimicrobials on the carpet with waterproof backing compared to carpets with water-permeable backing. These findings can inform development of antimicrobials for use on carpets contaminated with human norovirus.

Horizontal fire spread by foam-backed, polypropylene carpet

An eight year old boy was badly injured by a fire in his bedroom in May 2005. He spent his ninth birthday in intensive care and died a month later. This case study discusses a missing link into the pattern of fire development which made it difficult to identify the point of ignition. An absence of burning to the floor and isolated areas of burning seemed incongruous with the general pattern of fire development. Several fire investigation texts suggest that carpet cannot spread fire by itself; those texts that do mention the possibility, do not describe the mechanism in detail, nor what evidence an investigator might expect to see after the fire.Experimentation with samples of carpet gave good insight into the mechanism and its effects, thereby providing the missing link by which to connect the areas of burning and identify the point of origin. If elements of the mechanism described in this paper are known, a reader could discern enough from the many papers available to support a working hypothesis but as yet, there is no single paper that describes the phenomenon mechanistically from start to finish, especially to those who have not encountered elements of it before; hence, this paper presents some novel findings.The test involved polypropylene fibre carpets with integral polyurethane foam underlay, a very common type of carpet owing to its low cost and high durability. This is, therefore, an important mechanism of fire spread for fire investigators to be aware of and to understand. As this is a case study, rather than a research paper, the matters are dealt with empirically so the author cautions that when considering this mechanism in a new matter, the investigator should make their own tests of its validity.

Fungal diversity in homes and asthma morbidity among school-age children in New York City

BackgroundAsthma development has been inversely associated with exposure to fungal diversity. However, the influence of fungi on measures of asthma morbidity is not well understood. ObjectivesThis study aimed to test the hypothesis that fungal diversity is inversely associated with neighborhood asthma prevalence and identify specific fungal species associated with asthma morbidity. MethodsChildren aged 7–8 years (n = 347) living in higher (11–18%) and lower (3–9%) asthma prevalence neighborhoods were recruited within an asthma case-control study. Fungal communities were analyzed from floor dust using high-throughput DNA sequencing. A subset of asthmatic children (n = 140) was followed to age 10–11 to determine asthma persistence. ResultsNeighborhood asthma prevalence was inversely associated with fungal species richness (P = 0.010) and Shannon diversity (P = 0.059). Associations between neighborhood asthma prevalence and diversity indices were driven by differences in building type and presence of bedroom carpet. Among children with asthma at age 7–8 years, Shannon fungal diversity was inversely associated with frequent asthma symptoms at that age (OR 0.57, P = 0.025) and with asthma persistence to age 10–11 (OR 0.48, P = 0.043). Analyses of individual fungal species did not show significant associations with asthma outcomes when adjusted for false discovery rates. DiscussionLower fungal diversity was associated with asthma symptoms in this urban setting. Individual fungal species associated with asthma morbidity were not detected. Further research is warranted into building type, carpeting, and other environmental characteristics which influence fungal exposures in homes.

Performance Comparison between Different Types of Yellow Carpet Deployed by Local Governments

Performance Comparison between Different Types of Yellow Carpet Deployed by Local Governments

Implementasi Data Mining Untuk Prediksi Peramalan Penjualan Produk Hj Karpet Menggunakan Metode Linear Regression

HJ Karpet is a business engaged in commerce that sells a variety of carpet types and where inventory is crucial. The problem that HJ Karpet has always faced is an abundance of carpet inventory or overstock. Forecasting with the linear regression method is the solution for assisting with stock planning. Forecasting is the process of calculating future values using historical information. This study used linear regression to calculate and design the system, which was then implemented as a system. This study's objective is to forecast sales of HJ Karpet products using historical sales data provided by HJ Karpet for the purpose of generating a sales forecast. This study resulted in the development of a sales forecasting system that will be used to provide stock planning recommendations for the subsequent months. The results of the manual calculation using the linear regression equation predict a value of 52,093 for January 2023 with an error MAPE (mean absolute percentage error) calculation value of 5,667205%, indicating that the results of the regression-based forecasting model have a high degree of accuracy.

Kazakh traditional art of felt carpet

The article reveals the history of the formation and features of the formation of the traditional Kazakh felt carpet (syrmak), nominational principles and ethno-cultural semantics of the types of felt carpet and their names. In addition to the practical application of the product, it was determined that the names of the felt carpet (syrmak) and the associated stable expressions and proverbs were one of the national values that served as a regulator of aesthetic, ethical, social use. The history of the origin and development of traditional Kazakh syrmaks is studied. Materials were collected on the types and components of felt carpet, their regional, generic characteristics, materials, place and purpose of use, customs and traditions, technological techniques. Depending on the types and methods of artistic expression, there are hundreds of names in our language, and some of them are still not contained in the explanatory, regional, sectoral, encyclopedic dictionaries of the modern Kazakh language. In addition to syrmak, other rafter items, bedding and horse equipment were also identified in the article. It was investigated that the Kazakh decorative and applied art is closely connected with the art and culture of other ethnic groups of the Turkic world, and the technology of the development of the art of quilting felt carpet was laid back in ancient historical times. The ethnocultural semantic analysis of the artistic and cognitive nature of the traditional Kazakh felt carpet of art in the Turkic culture is carried out.

Spiral RF carpet for ion mass spectrometry with radioactive isotope beams

A new type of Radio-Frequency carpet for ion trapping and transport, which is made of a small number of long electrodes wrapped together as parallel spirals, starting from the central ion extraction aperture, and extending outwards, is introduced as an alternative to the currently used concentric geometry. The main features introduced are the possibility to construct high electrode densities RF carpets which enhances the characteristics of such devices, by improving the collection efficiency, and a simpler design that eliminates the complex electronic layer from the carpet. The feasibility of the proposed novel spiral geometry for RF carpets is investigated using ion optics simulations.

TRADITIONAL CARPETS OF THE LIVESTOCK POPULATION OF THE NURATA OASIS IN LATE XIX - BEGINNING OF XX CENTURY

The article is devoted to the specific types of traditional carpet weaving in the Nurata oasis and the research conducted by scientists to study them. The features of the traditions of carpet weaving, transmitted from ancestors to generations, the state of the carpet weaving traditions of the Nurata oasis, as well as historical and ethnographic features are studied. Attention is paid to the traditions of carpet weaving, which occupies a worthy place in the lifestyle of the oasis population, and the historical and ethnographic description of some types of carpets that have survived in the oasis to this day. Described attention to the production of types of carpets and proposals in this regard. In general, some aspects of the art of carpet weaving, which played a key role in the traditional crafts of the Turkmen, tom, palace and Uzbeks, Kazakhs, Tajiks, who have been living in the Nurata oasis for many years, are highlighted. After all, carpet weaving, which is the oldest traditional textile industry of mankind, has always had its own ethno-local features. A special place in this is occupied by the Nurata oasis, one of the historical and cultural regions of Uzbekistan.

Study of Body Conformation of Carpet Wool Type Chitarangi Sheep of India using Principal Component Analysis

Background: The principal component analysis is applied to identify minimum number of combined variables that account for maximum portion of the variance existing in all variables studied. Chitarangi is a lesser known carpet type wool sheep distributed in Fazilka and Muktsar districts of Punjab, Sri Ganganagar district of Rajasthan and the adjoining areas. The information on body biometry is a prerequisite to characterize the lesser known sheep population available in the country. Hence, it is important to describe the body conformation by recording minimum number of biometric traits. Methods: Body biometry traits of Chitarangi sheep, a lesser known carpet quality wool producing sheep population were studied using Principal Component Analysis. The traits studied were body length (BL), height at wither (HW), chest girth (CG), paunch girth (PG), ear length (EL), face length (FL), face width (FW), tail length (TL) and adult body weight (BW). The data were collected on 297 ewes in the breeding tract of Chitarangi sheep. The descriptive statistics were determined for all the traits. The phenotypic correlations between different body biometric traits were estimated using partial correlations. Principal components were estimated using correlation matrix. Principal component analysis (PCA), a multivariate approach, is used when the recorded traits are highly correlated. Rotation of principal components was through the transformation of the components to approximate a simple structure. Factor analysis using oblique (promax) rotation was used. All the analysis was carried out using the SPSS statistical package. Result: The averages for body weight and biometry traits confirmed large size of Chitarangi animals. Most of the phenotypic correlations amongst the studied traits were positive and significant (p less than 0.01). The three components extracted from nine principal components accounted for 69.06% of the total variance. The first component, which described body size of ewes, accounted for 43.68% of the total variation with high loading for BW, CG, PG, HW, BL and FL. The components two and three explained 13.54 and 11.83% of total variance, respectively. The communalities ranged from 0.490 (FL) to 0.888 (PG). The lower communalities for face length indicated lower contribution of the trait to explain the total variation than others. The study indicates that principal components provided a means of reduction in number of biometric traits to explain body confirmation of adult female Chitarangi sheep.

Particle Resuspension Dynamics in the Infant Near-Floor Microenvironment.

Carpet dust contains microbial and chemical material that can impact early childhood health. Infants may be exposed to greater quantities of resuspended dust, given their close proximity to floor surfaces. Chamber experiments with a robotic infant were integrated with a material balance model to provide new fundamental insights into the size-dependency of infant crawling-induced particle resuspension and exposure. The robotic infant was exposed to resuspended particle concentrations from 105 to 106 m-3 in the near-floor (NF) microzone during crawling, with concentrations generally decreasing following vacuum cleaning of the carpets. A pronounced vertical variation in particle concentrations was observed between the NF microzone and bulk air. Resuspension fractions for crawling are similar to those for adult walking, with values ranging from 10-6 to 10-1 and increasing with particle size. Meaningful amounts of dust are resuspended during crawling, with emission rates of 0.1 to 2 × 104 μg h-1. Size-resolved inhalation intake fractions ranged from 5 to 8 × 103 inhaled particles per million resuspended particles, demonstrating that a significant fraction of resuspended particles can be inhaled. A new exposure metric, the dust-to-breathing zone transport efficiency, was introduced to characterize the overall probability of a settled particle being resuspended and delivered to the respiratory airways. Values ranged from less than 0.1 to over 200 inhaled particles per million settled particles, increased with particle size, and varied by over 2 orders of magnitude among 12 carpet types.

\u201cSPOCU\u201d: scaled polynomial constant unit activation function

We address the following problem: given a set of complex images or a large database, the numerical and computational complexity and quality of approximation for neural network may drastically differ from one activation function to another. A general novel methodology, scaled polynomial constant unit activation function “SPOCU,” is introduced and shown to work satisfactorily on a variety of problems. Moreover, we show that SPOCU can overcome already introduced activation functions with good properties, e.g., SELU and ReLU, on generic problems. In order to explain the good properties of SPOCU, we provide several theoretical and practical motivations, including tissue growth model and memristive cellular nonlinear networks. We also provide estimation strategy for SPOCU parameters and its relation to generation of random type of Sierpinski carpet, related to the [pppq] model. One of the attractive properties of SPOCU is its genuine normalization of the output of layers. We illustrate SPOCU methodology on cancer discrimination, including mammary and prostate cancer and data from Wisconsin Diagnostic Breast Cancer dataset. Moreover, we compared SPOCU with SELU and ReLU on large dataset MNIST, which justifies usefulness of SPOCU by its very good performance.

Chitarangi sheep: A new carpet type ovine genetic resource of north-western India

Chitarangi, a lesser known carpet type wool sheep which inhabits Punjab and Rajasthan. The survey was conducted in order to characterize and evaluate the performance of this unexplored sheep population. The data on body biometry, phenotypic characters and other performance traits were collected based on personnel recording, observations and information provided by the sheep farmers. Shamaki wali, a more prevalent synonym for this sheep among the farmers, is derived from Shamaki village of Ghadsana mandi tehsil of Sriganganagar district. Farmers reported rearing this sheep since more than last 40-50 years. Chitarangi animals are medium to large in size. The coat colour is white. A red brown ring around eyes, patches on muzzle, red brown colour of distal half of the ear pinna and serration of various shape and depth in distal part of the ear pinna are distinct and distinguishing phenotypic characteristic of this breed. The light brown and chocolate colours of these markings were also observed in some of the animals. Ears are large in size and leafy. Both the sexes are polled; however, horns were noticed in some rams. Tail is thin and medium in length. The average body weight of adult males and females were 56.27±1.28 and 46.16±0.50 kg, respectively which ranged from 39 to 95 kg in males and 26 to 74 kg in females. The overall body length, height at wither, chest girth, paunch girth, face length, face width, ear length and tail length were also estimated. Fleece is not very dense and of good carpet quality. The fibre diameter, medulation and staple length were 42.22±0.10 μ, 56.60±4.22% and 5.90±0.32 cm, respectively which indicate that wool is of good carpet type. The age at first breeding in rams and age at first lambing in ewes were 12 to 15 and 18 to 23 months, respectively. The results indicate that the Chitarangi sheep is phenotypically different from other sheep breeds of the region and famous for carpet type wool.

Force-Sensor-Based Surface Recognition With Surface-Property-Dependent Walking-Speed Adjustment of Humanoid Robot

We report the development of a biped-robot system with real-time surface recognition and walking-speed adjustment to control the robot motion during walking on different types of surfaces. Four types of test surfaces (i.e. rough foam (RF), smooth foam (SF), thin carpet (TC) and smooth table (ST)) are considered in the system verification. For surface-property recognition we use ultra-thin-membrane force sensors, mounted under the robot feet, and a classification circuit, implemented on an Arduino Uno board. The walking-speed adjustment is performed with an external control circuit, which receives the surface-recognition signal from the classification circuit and sends a feedback signal to the robot controller (i.e. RCB-4HV) for adjusting the walking speed accordingly. We applied the nearest-neighbor-classification algorithm with the Euclidean-distance measure and a set of reference data, to distinguish between the four test surfaces based on the robot's real-time walking pattern. The mean absolute value (MAV) feature descriptor is used to generate four different types of reference walking pattern, corresponding to the four different surfaces. In our experiments it is observed, that the ST surface performs best in terms of average surface-recognition latency (SRL) (~3.6 sec) during walking on same surface. On the other hand, the surface transition from TC to SF showed minimum surface-transition latency (STL) (~8.2 sec) with correct speed change from 135 to 160 robot-motor-configuration frames per stride (frames/stride), while the transition from SF to TC surfaces showed maximum STL (~11.6 sec) including speed change from 160 to 135 frames/stride. The obtained results are useful for development of the next generation of surface-recognition and speed-adjustment systems, implemented in humanoid robots to enable balanced and stable walking in environments with multiple changed surface properties.

Study on Tuft Withdrawal Force and Compressibility of Hand-Tufted Carpet

Carpets are mostly used for floor coverings. Ninety per cent of the carpet constructed is tufted carpet (Crawshaw in Carpet manufacture, WRONZ Developments, Christchurch, 2002). The present study aims to analyse the effect of fineness of pile yarn and number of ply of pile yarn on tuft withdrawal force and compression behaviour of hand-tufted carpet. Nine different types of hand-tufted carpets were prepared by varying the above-mentioned variables. Samples were analysed in terms of their physical and structural parameters as well as thickness loss, compression percentage and tuft withdrawal force. It has been observed that more tuft withdrawal force is required for coarser pile yarn and more number of ply of pile yarn. Compression percentage decreases as the number of ply of pile yarn increases. Compression percentage also increases as the yarn becomes finer. But thickness loss increases as the yarn becomes finer, and the same decreases as the number of ply of pile yarn increases. Analysis of variance shows that number of ply of pile yarn and fineness of pile yarn are both significant parameters to control the compressibility and tuft withdrawal force.

Phase quantized quasi-Sierpinski carpet reflector for OAM beam generation

This work proposes a quasi-Sierpinski carpet type reflecting surface. The reflector incorporates remodeled Jerusalem type sub-wavelength elements. The element arrangement ensures a 3-bit phase quantized encoding for the reflected beam. Microstrip antenna feed illuminates this reflector. We start with EM simulation of a broadband unit-cell reflector. We assume that the final reflector based on such unit-cell shall show broadband characteristic. The simulated beam from the reflector, due to spatial arrangements of the unit-cells, showed the fundamental mode of orbital angular momentum vortex beams. Experimental verification of fabricated prototype shows good agreement with simulated far-field results at 9.5 GHz, 10 GHz, 10.5 GHz, and 11 GHz which indicate a broadband characteristic.

Сталактитовые формы в архитектуре средневекового Крыма

Architectural and structural details in the form of stalactites are known on monuments which belong to different faiths and ethnic groups, and they had a diverse purpose. Earliest objects are represented by such outstanding structures as the portal, the mihrab and the minaret of the Uzbek mosque in the Solkhat (1314), the portal of the medresse Inji-bey Hatun, in the same place (1332/33), the portal and the mihrab of the mosque in Sheikh-Koy (1358). Their architectonics and stylistic features demonstrate the building traditions that prevailed in the territory of Asia Minor during the Seljuk Emirates. After 1475 the stalactite details of the Crimean monuments gradually begin to take on the forms, which are typical of the Ottoman architecture. Also in use were the details of the 14th century, which survived and received a new life in secondary use in a number mosques of the 16th–17th centuries. External mihrabs of the Juma-Jami in the Gozlow, which was built in the 1552 upon the project of the chief architect of the Porta — Hodzha Sinan’, are reminiscent of classical examples of the Seljuk time. The archway of the durbe Hadji Giray (1501) portal’s in Salachik has architectonics, the sources of which originate in the Anatolian wooden architecture. Among the buildings ofthe 18th century the main mihrab of the mosque in the Pionerskoe village stands out. The construction of its arch in many places is simulated by the use of voluminous geometric ornament of carpet type.

Efficacy of Silver Dihydrogen Citrate and Steam Vapor against a Human Norovirus Surrogate, Feline Calicivirus, in Suspension, on Glass, and on Carpet.

Carpets and other soft surfaces have been associated with prolonged and reoccurring human norovirus (HuNoV) outbreaks. Environmental hygiene programs are important to prevent and control HuNoV outbreaks. Despite our knowledge of HuNoV transmission via soft surfaces, no commercially available disinfectants have been evaluated on carpets. Our aim was to adapt a current standardized method for virucidal testing by assessing two disinfection technologies, silver dihydrogen citrate (SDC) and steam vapor, against one HuNoV surrogate, feline calicivirus (FCV), on wool and nylon carpets. First, we evaluated the effect of both technologies on the appearance of carpet. Next, we evaluated the efficacy of SDC in suspension and the efficacy of SDC and steam vapor against FCV on a glass surface, each with and without serum. Lastly, we tested both technologies on two types of carpet, wool and nylon. Both carpets exhibited no obvious color changes; however, SDC treatments left a residue while steam vapor left minor abrasions to fibers. SDC in suspension and on glass reduced FCV by 4.65 log10 and >4.66 log10 PFU, respectively, but demonstrated reduced efficacy in the presence of serum. However, SDC was only efficacious against FCV on nylon (3.62-log10 PFU reduction) and not wool (1.82-log10 PFU reduction). Steam vapor reduced FCV by >4.93 log10 PFU on glass in 10 s and >3.68 log10 PFU on wool and nylon carpet carriers in 90 s. There was a limited reduction of FCV RNA under both treatments compared to that of infectivity assays, but RNA reductions were higher in samples that contained serum.IMPORTANCE Human noroviruses (HuNoV) account for ca. 20% of all diarrheal cases worldwide. Disease symptoms may include diarrhea and vomit, with both known to contribute to transmission. The prevention and control of HuNoV are difficult because they are environmentally resilient and resistant to many disinfectants. Several field studies have linked both hard and soft surfaces to HuNoV outbreaks. However, many disinfectants efficacious against HuNoV surrogates are recommended for hard surfaces, but no commercially available products have demonstrated efficacy against these surrogates on soft surfaces. Our research objectives were to evaluate liquid and steam-based technologies in suspension and on hard surface carriers in addition to adapting and testing a protocol for assessing the virucidal effects of disinfection technologies on carpet carriers. These results will inform both the government and industry regarding a standard method for evaluating the virucidal effects of disinfectants on carpet while demonstrating their efficacy relative to suspension and hard-surface tests.

Efficiency assessment of Iranian Handmade Carpet Company by network DEA

Different categories of Iranian handmade carpet are produced each year. Since of resource limitation, it is so important for managers to allocate more resources to the most efficient categories. So the main purpose of this illustration is to consider most efficient types of carpet in production and sales stages. To do so, different categories of Iranian handmade carpet are considered as DMUs. This study utilizes network DEA for constructing a model to analyze total and partial efficiency of Iranian Handmade Carpet Company (IHCC) simultaneously. IHCC consists of three main departments that are working jointly to maximize productivity of the firm; therefore, the case of IHCC is a multi-stage system with shared intermediate variables, extra inputs to the second stage and undesired outputs. The novelty of this paper is the methodology used for calculating the efficiency which is based on multi-objective programming. Results of experimental data of IHCC is summarized in order to prepare some brilliant management strategies based on partial and total efficiency scores of different carpet categories. Since the lack of familiar researches in the area of carpet industry efficiency measurement, this research will provide valuable information for decision makers.

Recovery Optimization and Survival of the Human Norovirus Surrogates Feline Calicivirus and Murine Norovirus on Carpet.

Carpets have been implicated in prolonged and reoccurring outbreaks of human noroviruses (HuNoV), the leading cause of acute gastroenteritis worldwide. Viral recovery from environmental surfaces, such as carpet, remains undeveloped. Our aim was to determine survival of HuNoV surrogates on an understudied environmental surface, carpet. First, we measured the zeta potential and absorption capacity of wool and nylon carpet fibers, we then developed a minispin column elution (MSC) method, and lastly we characterized the survival of HuNoV surrogates, feline calicivirus (FCV) and murine norovirus (MNV), over 60 days under 30 and 70% relative humidity (RH) on two types of carpet and one glass surface. Carpet surface charge was negative between relevant pH values (i.e., pH 7 to 9). In addition, wool could absorb approximately two times more liquid than nylon. The percent recovery efficiency obtained by the MSC method ranged from 4.34 to 20.89% and from 30.71 to 54.14% for FCV and MNV on carpet fibers, respectively, after desiccation. Overall, elution buffer type did not significantly affect recovery. Infectious FCV or MNV survived between <1 and 15 or between 3 and 15 days, respectively. However, MNV survived longer under some conditions and at significantly (P < 0.05) higher titers compared to FCV. Albeit, surrogates followed similar survival trends, i.e., both survived longest on wool then nylon and glass, while 30% RH provided a more hospitable environment compared to 70% RH. Reverse transcription-quantitative PCR signals for both surrogates were detectable for the entire study, but FCV genomic copies experienced significantly higher reductions (<3.80 log10 copies) on all surfaces compared to MNV (<1.10 log10 copies).IMPORTANCE Human noroviruses (HuNoV) are the leading cause of acute gastroenteritis worldwide. Classical symptoms of illness include vomiting and diarrhea which could lead to severe dehydration and death. HuNoV are transmitted by the fecal-oral or vomitus-oral route via person-to-person contact, food, water, and/or environmental surfaces. Published laboratory-controlled studies have documented the environmental stability of HuNoV on hard surfaces, but there is limited laboratory-based evidence available about survival on soft surfaces, e.g., carpet and upholstered furniture. Several epidemiological reports have suggested soft surfaces may be HuNoV fomites illustrating the importance of conducting a survival study. The three objectives of our research were to demonstrate techniques to characterize soft surfaces, develop a viral elution method for carpet, and characterize the survival of HuNoV surrogates on carpet. These results can be used to improve microbial risk assessments, the development of much-needed soft surface disinfectant, and standardizing protocols for future soft surface studies.