Aggregate-level Lead Exposure and Child Maltreatment.

The purpose of this study was to examine the possible ecological association between aggregate blood lead levels (BLL) and rates of child maltreatment. To this end, we employed an ecologic study design, analyzing results from 59,645 child BLL tests between the years 1996 and 2007, and 6,640 substantiated maltreatment investigations from 2006 to 2016 in a large Midwest city. Separate Bayesian spatial Poisson conditional autoregressive (CAR) and Bayesian spatial zero-inflated Poisson CAR models were used to predict the occurrence of maltreatment.Bivariate results showed that aggregate rates of maltreatment increased as aggregate BLL increased. Multivariate results showed that medium-exposure BLL census tracts (OR = 1.38) and high-exposure BLL tracts (OR = 1.38) had increased odds of substantiated investigations for any maltreatment compared to low BLL census tracts even after controlling for crime rates, age of the housing stock, and concentrated disadvantage. Our findings, considered with prior research, continue to reveal a confluence of deleterious outcomes in areas where exposure to lead seems elevated. In this case, child maltreatment also appears to represent a macro-level correlate of aggregate lead exposure. Yet our results preclude any causal inference, and further research on the intersection of child maltreatment with environmental toxins is needed to determine if contaminant abatement should be considered as a possible maltreatment prevention strategy.

Antibiotic use in goats: role of experience and education of Missouri veterinarians.

BACKGROUND: In a previous study, we found that rates of antibiotic residues in goat carcasses in Missouri were three times the published national average, warranting further research in this area. METHODS: We conducted a cross-sectional survey of goat veterinarians to determine attitudes and practices regarding antibiotics, recruiting 725 veterinarians listed on the American Association of Small Ruminant Practitioners (AASRP) website and 64 Missouri Veterinary Medical Association (MVMA) veterinarians. RESULTS: We collected 189 responses (26.1%) from AASRP members (170 valid) and 8 (12.5%) from MVMA veterinarians totalling 178 responses. While the vast majority of all veterinarians indicated that they prescribed antibiotics less than half of the time, Missouri veterinarians indicated that they spent more time treating goats for overt disease like intestinal parasites and less time on proactive practices such as reproductive herd health management comparatively. While veterinarians agreed that antibiotic resistance was a growing concern, veterinarians outside of Missouri seemed more confident that their own prescription practices was not a contributor. Although nationally most veterinarians felt that attending continuing education classes was beneficial, 73.4% in other states attended classes on antibiotic use compared to only four of the nine Missouri veterinarians. CONCLUSION: Missouri veterinarians had less veterinary experience than veterinarians in other states, and this, in conjunction with low continuing education requirements in Missouri relative to most other states, may hinder development of more proactive and effective client-veterinary relationships.

Resuspension of house dust and allergens during walking and vacuum cleaning.

Conventional wisdom has been that hard, resilient surfaces resuspend fewer particles than carpeted surfaces, however, exceptions to this have been demonstrated and uncertainty remains about the factors that lead to this resuspension, notably, the effect of vacuum cleaning on either increasing or reducing resuspension from flooring. The purpose of this study was to determine how resuspension of house dust by aerodynamic size or particle type, including cat allergen and bacterial endotoxin, is affected by flooring, dust loading, embedding dust, and walking/cleaning activities. House dust was blown in and allowed to settle in a walk-in chamber after overnight deposition followed by walking or a vacuum cleaning procedure. Using an aerosol particle sizer and large-volume air samplers at different heights in the chamber, concentrations of airborne particles, resuspension rates, and fractions were computed for four types of flooring conditions during six walking activities. Carpeting resulted in significantly more airborne cat allergen and airborne endotoxin than a laminate floor. Height does have an effect on measured allergen over carpet and this is apparent with concentrations at the infant and adult air samplers. Walking on laminate flooring resuspends less house dust than walking on an equally dusty carpeted floor, where dust is entirely on the surface of the carpet. However, vacuum cleaning a laminate floor resuspended more dust than vacuum cleaning carpets, at large particle sizes of 5 µm and 10 µm. Activities following a deep cleaning of hard resilient or a carpeted surface is likely to leave no differences in resuspended particles between them.

Inactivation of Mold Spores from Moist Carpet Using Steam Vapor: Contact Time and Temperature.

Steam vapor has been shown to reduce viable mold spores in carpet, but the minimal effective temperature and contact time has not been established. This study evaluated the effectiveness of steam vapor in reducing the number of viable mold spores in carpet as a function of temperature and contact time. Seventy carpet samples were inoculated with a liquid suspension of Cladosporium sphaerospermum and incubated over a water-saturated foam carpet pad for 24 hr. Steam was applied to the samples as the temperature was measured from the carpet backing. Contact time was closely monitored over seven time intervals: 0, 2, 4, 8, 12, 16, and 20 sec. Following steam vapor treatment, mold spores were extracted from the carpet samples and the extract was plated on DG-18 plates at 1:1, 1:10, 1:100 dilutions followed by one week of incubation. Raw colony forming units were determined using an automated colony counter and adjusted based on dilution factor, extraction volume, and plated volume. Analysis of variance and linear regression were used to test for statistically significant relationships. Steam contact time exhibited a linear relationship to observed temperature of carpet backing (F = 90.176, R(2) = 0.609). Observed temperature of carpet backing had a positive relationship to percent reduction of mold (F = 76.605, R(2) = 0.569). Twelve seconds of steam vapor contact time was needed to achieve over 90% mold reduction on moist carpet.

Mold management of wetted carpet.

This study evaluated the growth and removal of fungi on wetted carpet using newly designed technologies that rely on physical principles of steam, heat, and fluid flow. Sixty samples of carpet were embedded with heat-treated house dust, followed by embedding, wearing with a hexapod, and wetting. Samples were inoculated using a liquid suspension of Cladosporium sphaerospermum prior to placement over a water-saturated foam pad. Incubation times were 24 hr, 7 days, and 30 days. Cleaning was performed using three methods; high-flow hot water extraction, hot water and detergent, and steam. Fungal loading increased from approximately 1500 colony forming units per area (CFU/cm(2)) in 24 hr to a maximum of approximately 10,200 CFU/cm(2) after 7 days with a slight decline to 9700 CFU/cm(2) after 30 days incubation. Statistically significant differences were found among all three methods for removal of fungi for all three time periods (p < 0.05). Steam-vapor was significantly better than the alternative methods (p <0.001) with over 99% efficiency in mold spore decline from wetted carpet after 24 hr and 30 days, and over 92% efficiency after 7 days. The alternative methods exhibited lower efficiencies with a decline over time, from a maximum of 82% and 81% at 24 hr down to 60% and 43% at 30 days for detergent-hot water and high-flow, hot water extraction, respectively. The net effect of the mold management study demonstrates that while steam has a consistent fungal removal rate, the detergent and high-flow, hot water methods decline in efficiency with increasing incubation time.

Inactivation of dust mites, dust mite allergen, and mold from carpet.

Carpet is known to be a reservoir for biological contaminants, such as dust mites, dust mite allergen, and mold, if it is not kept clean. The accumulation of these contaminants in carpet might trigger allergies or asthma symptoms in both children and adults. The purpose of this study is to compare methods for removal of dust mites, dust mite allergens, and mold from carpet. Carpets were artificially worn to simulate 1 to 2 years of wear in a four-person household. The worn carpets were inoculated together with a common indoor mold (Cladosporium species) and house dust mites and incubated for 6 weeks to allow time for dust mite growth on the carpet. The carpets were randomly assigned to one of the four treatment groups. Available treatment regimens for controlling carpet contaminants were evaluated through a literature review and experimentation. Four moderately low-hazard, nondestructive methods were selected as treatments: vacuuming, steam-vapor, Neem oil (a natural tree extract), and benzalkonium chloride (a quaternary ammonium compound). Steam vapor treatment demonstrated the greatest dust mite population reduction (p < 0.05) when compared to other methods. The two physical methods, steam vapor and vacuuming, have no statistically significant efficacy in inactivating dust mite allergens (p = 0.084), but have higher efficacy when compared to the chemical method on dust mite allergens (p = 0.002). There is no statistically significant difference in the efficacy for reducing mold in carpet (p > 0.05) for both physical and chemical methods. The steam-vapor treatment effectively killed dust mites and denatured dust mite allergen in the laboratory environment.

Do new wipe materials outperform traditional lead dust cleaning methods?

Government guidelines have traditionally recommended the use of wet mopping, sponging, or vacuuming for removal of lead-contaminated dust from hard surfaces in homes. The emergence of new technologies, such as the electrostatic dry cloth and wet disposable clothes used on mopheads, for removal of dust provides an opportunity to evaluate their ability to remove lead compared with more established methods. The purpose of this study was to determine if relative differences exist between two new and two older methods for removal of lead-contaminated dust (LCD) from three wood surfaces that were characterized by different roughness or texture. Standard leaded dust, <75 µm, was deposited by gravity onto the wood specimens. Specimens were cleaned using an automated device. Electrostatic dry cloths (dry Swiffer), wet Swiffer cloths, paper shop towels with non-ionic detergent, and vacuuming were used for cleaning LCD from the specimens. Lead analysis was by anodic stripping voltammetry. After the cleaning study was conducted, a study of the coefficient of friction was performed for each wipe material. Analysis of variance was used to evaluate the surface and cleaning methods. There were significant interactions between cleaning method and surface types, p = 0.007. Cleaning method was found be a significant factor in removal of lead, p <0.001, indicating that effectiveness of each cleaning methods is different. However, cleaning was not affected by types of surfaces. The coefficient of friction, significantly different among the three wipes, is likely to influence the cleaning action. Cleaning method appears to be more important than texture in LCD removal from hard surfaces. There are some small but important factors in cleaning LCD from hard surfaces, including the limits of a Swiffer mop to conform to curved surfaces and the efficiency of the wetted shop towel and vacuuming for cleaning all surface textures. The mean percentage reduction in lead dust achieved by the traditional methods (vacuuming and wet wiping) was greater and more consistent compared to the new methods (electrostatic dry cloth and wet Swiffer mop). Vacuuming and wet wiping achieved lead reductions of 92% ± 4% and 91%, ± 4%, respectively, while the electrostatic dry cloth and wet Swiffer mops achieved lead reductions of only 89 ± 8% and  81 ± 17%, respectively.

Removal of lead contaminated dusts from hard surfaces.

Government guidelines have widely recommended trisodium phosphate (TSP) or "lead-specific" cleaning detergents for removal of lead-contaminated dust (LCD) from hard surfaces, such as floors and window areas. The purpose of this study was to determine if low-phosphate, non-lead-specific cleaners could be used to efficiently remove LCD from 3 types of surfaces (vinyl flooring, wood, and wallpaper). Laboratory methods were developed and validated for simulating the doping, embedding, and sponge cleaning of the 3 surface types with 4 categories of cleaners: lead-specific detergents, nonionic cleaners, anionic cleaners, and trisodium phosphate (TSP). Vinyl flooring and wood were worn using artificial means. Materials were ashed, followed by ultrasound extraction, and anodic stripping voltammetry (ASV). One-way analysis of variance approach was used to evaluate the surface and detergent effects. Surface type was found to be a significant factor in removal of lead (p < 0.001). Vinyl flooring cleaned better than wallpaper by over 14% and wood cleaned better than wallpaper by 13%. There was no difference between the cleaning action of vinyl flooring and wood. No evidence was found to support the use of TSP or lead-specific detergents over all-purpose cleaning detergents for removal of lead-contaminated dusts. No-phosphate, non-lead-specific detergents are effective in sponge cleaning of lead-contaminated hard surfaces and childhood lead prevention programs should consider recommending all-purpose household detergents for removal of lead-contaminated dust after appropriate vacuuming.

Influence of wear, pile height, and cleaning method on removal of mite allergen from carpet.

Carpet is a major sink for house dust mite allergen. Vacuum extraction methods have been shown to reduce concentrations of such allergen in dust, but the influence of carpet construction and cleaning parameters on the efficiency of extraction is poorly understood. The objective of this study was to determine the effect of construction, degree of wear, and cleaning method on ease of removal of the primary allergen (Der f I) derived from the North American house-dust mite, Dermatophagoides Farinae. Carpets of different pile heights were seeded with house dust, some were then subjected to artificial wear, and all were then either dry vacuumed or wet extracted. The Der f I content of carpet cores was measured at each stage. As a result, the degree of wear and pile height were shown to be the two most important factors determining ease of Der f I removal from carpet. For worn carpet, dry vacuuming of short pile constructions was shown to be significantly more effective (p 61%) for unworn carpet than for worn carpet (<30%). Only minor differences between types of cleaning method (wet vs. dry) were found. This study suggests that carpets differ greatly in their propensity to retain allergens, and that a consideration of carpet age, construction, and cleaning regime is important when advising the merits of different floor covering types, and on allergen avoidance techniques.