Retrospective Risk Assessment of Injuries and Fatalities in the Forestry and Logging Workforce in the United States, 2003-2019

OBJECTIVES

The objectives of this study on the forestry and logging workforce are to: 1) Analyze causes of injuries/fatalities to inform future intervention studies focused on risk mitigation, 2) determine whether there are any trends or associations between work-related risk factors and workplace injuries/fatalities over a 16-year period (2003-2019), and 3) identify knowledge gaps related to injuries and fatalities for future studies to address.

METHODS

Data on fatalities, injuries, and illnesses of the forestry and logging workforce from the United States Bureau of Labor Statistics were analyzed. Correlation analysis (p < .05) was conducted to assess the relationship between causes of forestry and logging workforce fatalities by cause of fatality in the United States. Injury and fatality rates were calculated for each year (fatalities: 2003-2018; injuries: 2005-2019) and time span-specific incidence rates were calculated by cause.

RESULTS

Contact with objects and equipment was the primary cause of injuries and fatalities in the forestry and logging workforce during the study period. Transportation-related incidents ranked second as the cause of fatalities, while the category of falls, slips, and trips was the second leading cause of injuries.

CONCLUSION

Gaps in occupational health and safety identified by this study should be collaboratively addressed by researchers and the forestry industry.

Antibacterial efficacy, mode of action, and safety of a novel nano-antibiotic against antibiotic-resistant Escherichia coli strains

Globally rising antibiotic-resistant (AR) and multi-drug resistant (MDR) bacterial infections are of public health concern due to treatment failure with current antibiotics. Enterobacteria, particularly Escherichia coli, cause infections of surgical wound, bloodstream, and urinary tract, including pneumonia and sepsis. Herein, we tested in vitro antibacterial efficacy, mode of action (MoA), and safety of novel amino-functionalized silver nanoparticles (NH2-AgNP) against the AR bacteria. Two AR E. coli strains (i.e., ampicillin- and kanamycin-resistant E. coli), including a susceptible strain of E. coli DH5α, were tested for susceptibility to NH2-AgNP using Kirby-Bauer disk diffusion and standard growth assays. Dynamic light scattering (DLS) was used to determine cell debris and relative conductance was used as a measure of cell leakage, and results were confirmed with transmission electron microscopy (TEM). Multiple oxidative stress assays were used for in vitro safety evaluation of NH2-AgNP in human lung epithelial cells. Results showed that ampicillin and kanamycin did not inhibit growth in either AR bacterial strain with doses up to 160 μg/mL tested. NH2-AgNP exhibited broad-spectrum bactericidal activity, inhibiting the growth of all three bacterial strains at doses ≥1 μg/mL. DLS and TEM revealed cell debris formation and cell leakage upon NH2-AgNP treatment, suggesting two possible MoAs: electrostatic interactions followed by cell wall damage. Safety evaluation revealed NH2-AgNP as noncytotoxic and antioxidative to human lung epithelial cells. Taken together, these results suggest that NH2-AgNP may serve as an effective and safer bactericidal therapy against AR bacterial infections compared to common antibiotics.

Development of novel compact wind tunnel for testing efficacy of insecticide formulated products in mosquitoes

BACKGROUND

Ultra-low volume (ULV) space sprays aerosolize insecticide formulated products (FP) to contact flying mosquitoes, while barrier sprays expose mosquitoes to FP residue on vegetation and other surfaces. Centers for Disease Control and Prevention bottle bioassays used to assess insecticide resistance are based on residual active ingredient (AI) exposure and do not directly relate to FP efficacy. The current pilot study developed a novel compact wind tunnel for mosquito exposure to FP. Caged Aedes albopictus and Culex pipiens/quinquefasciatus were exposed to undiluted Biomist®3 + 15 FP (permethrin AI) or air (control) within the wind tunnel, transferred to new cages, and held in a 28 °C incubator. Separate mosquitoes were exposed to residual permethrin AI (8 μg mL-1 ) in bottle bioassays. Mortality was monitored 15, 30, 60, and 120 min post-exposure.

RESULTS

Chi-square tests (P < 0.05) showed significantly higher mortality in Aedes compared to Culex populations for most time points in both bioassay and wind tunnel exposure groups. As expected, mosquitoes exposed to Biomist®3 + 15 showed higher mortality rates than bottle bioassay exposure to permethrin. Two Culex colonies resistant to permethrin in bottle bioassays were susceptible to Biomist®3 + 15 in the wind tunnel.

CONCLUSION

The novel compact wind tunnel developed here may be an alternative to field trials for testing FP efficacy, avoiding factors such as weather, logistical planning, and extended personnel hours. The wind tunnel could allow programs to conveniently test efficacy of multiple FP. Comparisons of different insecticide exposure methods provide practical information to inform operational decisions. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Assessment of barrier treatments impacting Aedes albopictus (diptera: culicidae) using lambda-cyhalothrin and pyriproxyfen in a suburban neighborhood in Eastern North Carolina, 2018

Pyrethroids are commonly used in barrier treatments but less is known about how mosquitoes are affected by the simultaneous application of an insect growth regulator (i.e., pyriproxyfen) used in barrier treatments. This field study, conducted from May 14 - October 16, 2018, evaluated the effect of lambda-cyhalothrin (pyrethroid adulticide) and pyriproxyfen on the reproduction (measured by fecundity and adult emergence) and abundance of Aedes albopictus. Nine properties were treated with Demand®CS 0.06% + Archer® 0.010% (every 60 days) and three control properties received no treatment (N=12 total properties). No significant (P>0.05) differences were observed between abundance of Ae. albopictus in treatment compared to control groups. However, significant differences were observed in abundance of Ae. albopictus adults between weeks at both control (P = 0.003) and treatment (P < 0.0001) properties. Results from our research show that continued studies are needed to determine the efficacy of barrier treatments for this species.           .

Occupational exposure to solar ultraviolet radiation in an eastern North Carolina university outdoor setting during the four seasons

Outdoor workers perform tasks throughout the year that expose them to solar ultraviolet radiation (UVR) and increase their risk of UVR-related adverse health effects. Multiple studies on occupational solar UVR exposures during summer have been published but similar investigations during other seasons are limited. The purpose of this study was to assess solar UVR exposure in an eastern North Carolina university setting during all four seasons (fall, winter, spring, and summer) to assess risk for outdoor workers, particularly groundskeepers, throughout the year. UVR effective irradiance (UVReff) was measured by area monitoring using a digital data-logging radiometer and a weatherproof UVR detector for 164 days from October 2020 to October 2021. Results showed that hourly and daily mean UVReff exceeded the 1-hr and 8-hr ACGIH Threshold Limit Values (TLVs), respectively, in all months and seasons at varying degrees. Winter had the lowest mean UVReff (3.4 × 10-3 ± 1.7 × 10-3 mW/cm2), but 91.1% and 100% of the hourly and daily UVReff measurements, respectively, still exceeded the TLVs. This study demonstrates the risk of overexposure to solar UVR among outdoor workers during cold months and seasons and the importance of implementing UVR protection throughout the year.

A scoping review on the effects of Varroa mite (Varroa destructor) on global honey bee decline

Arguably the most ecologically and economically valuable pollinators worldwide, honey bees play a significant role in food production and enrich biodiversity through pollination. Varroa destructor is an invasive ectoparasitic mite that attacks and feeds on European honey bee, Apis mellifera. Because literature on the effectiveness and sustainability of various treatment modalities available for Varroa mite control in honey bee colonies are scattered, this scoping review was conducted to serve as a guiding document with a focus on: (1) identifying the detrimental impact Varroa mites have on the European honey bee; (2) determining current methods for Varroa mite control and their limitations; (3) examining current market landscape and key players in the pesticide market; and (4) identifying opportunities for more sustainable Varroa mite control methods. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, 397 articles published between 1998 and 2022 were screened; of which 65 articles were retained using inclusion/exclusion criteria, which were systematically analyzed in-depth, information extracted, and included in this scoping review. The results suggest that Varroa mites are one of the predominant causes of global honey bee decline as they lack natural resistance to Varroa mites, thereby negatively affecting honey bee reproduction and immunity, killing broods, and transmitting pathogenic viruses to colonies. Further, our findings suggest that: apiarists have many options for Varroa control, but no method has proven to be effective, safe and nonpersistent in the environment; adoption of nano-pesticides and development of sustainable alternatives to traditional pesticides are key drivers for growing pesticide market; and nano-pesticides may have potential to serve as an effective, safe and non-ecopersistent pesticide for Varroa mite and associated virus control. In conclusion, this review highlights an unmet need for effective and sustainable control strategies and tools for Varroa mite and virus control.

Retrospective Assessment of Preparedness for Mosquito Control Post-Hurricane Florence in North Carolina

OBJECTIVES

Ideally, mosquito control programs (MCPs) use surveillance to target control measures to potentially dangerous mosquito populations. In North Carolina (NC), where there is limited financial support for mosquito control, communities may suffer from mosquito-related issues post-hurricane due to lack of existing MCPs. Here, study objectives were to (1) investigate the emergency response of a subset of NC counties post-Hurricane Florence and (2) develop guidelines and policy recommendations to assist MCPs in post-hurricane mosquito control response.

METHODS

A survey was administered to a subset of eastern NC counties (an area previously impacted by hurricanes) with various levels of MCPs (from none to well-developed).

RESULTS

All respondents indicated that having Federal Emergency Management Agency (FEMA) training would be helpful in developing a post-hurricane emergency response plan for mosquito control. There was concern related to a lack of knowledge of emergency control methods (eg, aerial/ground, adulticiding/larviciding) post-hurricane. MCP structure (eg, infrastructure, resources, operational plans/policies) could facilitate response activities and help ensure necessary emergency financial support from agencies such as FEMA.

CONCLUSIONS

Mosquito control post-hurricane protects public health. Public health and other agencies can be networking resources for MCPs. Policy recommendations include implementation of routine FEMA assistance training workshops to improve an understanding of processes involved in assistance and reimbursement.

Geographic information system protocol for mapping areas targeted for mosquito control in North Carolina

Geographic information systems (GIS) can be used to map mosquito larval and adult habitats and human populations at risk for mosquito exposure and possible arbovirus transmission. Along with traditional methods of surveillance-based targeted mosquito control, GIS can help simplify and target efforts during routine surveillance and post-disaster (e.g., hurricane-related flooding) to protect emergency workers and public health. A practical method for prioritizing areas for emergency mosquito control has been developed and is described here. North Carolina (NC) One Map was used to identify state-level data layers of interest based on human population distribution and mosquito habitat in Brunswick, Columbus, Onslow, and Robeson Counties in eastern NC. Relevant data layers were included to create mosquito control treatment areas for targeted control and an 18-step protocol for map development is discussed. This protocol is expected to help state, territorial, tribal, and/or local public health officials and associated mosquito control programs efficiently create treatment area maps to improve strategic planning in advance of a disaster. This protocol may be applied to any NC county and beyond, thereby increasing local disaster preparedness.

Retrospective spatiotemporal analysis of malaria cases reported between 2000 and 2020 in North Carolina, USA

BACKGROUND

There are 1,000-2,000 cases of malaria diagnosed in the United States annually and most are imported.

METHODS

Malaria cases reported between 2000 and 2020 in North Carolina (NC) were analyzed (NC Department of Health and Human Services, Division of Public Health). Differences in numbers of NC malaria cases were further analyzed by year, month, county, gender, age, and country of origin.

RESULTS

Most cases originated from travelers visiting Africa and returning to NC (i.e., Mecklenburg [N = 162 cases], Wake [N = 153], Guilford [N = 103], Durham [N = 74], and Cumberland [N = 41] Counties). Per capita analysis (i.e., per 100,000 population) was used to correct for differences in NC county population sizes and Durham (N = 22.8), Guilford (N = 19.0), Onslow (N = 14.7), Mecklenburg (N = 14.5), Wake (N = 13.5), Orange (N = 12.8) and Cumberland (N = 12.2) Counties showed the highest cases. Malaria was more prevalent among males (N = 532) relative to females (N = 245), and this difference was statistically significant.

CONCLUSIONS

Travelers visiting malaria-endemic regions should be educated on malaria prevention measures (e.g., chemoprophylaxis, mosquito repellent). These measures should be readily available to travelers. The malaria registry in NC should be improved by requiring additional data related to imported malaria cases.

Survey of United States Mosquito Control Programs Reveals Opportunities to Improve the Operational Value of Centers for Disease Control and Prevention Bottle Bioassays

Mosquito control programs have increasingly used Centers for Disease Control and Prevention bottle bioassays (BB) to evaluate insecticide resistance (IR). The reported utility, benefits, and limitations of BB and other methods were assessed via electronic survey of U.S. mosquito control professionals to identify potential areas for improvement, future study, and professional training. Opportunities were identified to improve BB operational value and IR detection.

Evaluation of surface versus total permethrin content in permethrin-treated clothing: Implications for protection against mosquitoes

Permethrin is a synthetic pyrethroid insecticide used to treat uniforms (e.g. military, foresters) and other clothing to protect people against pests (e.g., mosquitoes, ticks). Pests contacting the surface of permethrin-treated clothing (PTC) are repelled and/or killed, depending on the dose and duration of exposure. Hence, it is important to assess the amount of permethrin on the surface of clothing. Fabric swatches prepared using two commercially available permethrin treatments (Insect Shield® & Sawyer Repellant) and one laboratory created treatment (4g permethrin/L) were tested. A Martindale Abrasion and Pilling Tester (MAPT) and gas chromatography were used to assess surface permethrin content (SPC) and total permethrin content (TPC). Sawyer PTC had the highest SPC (mean ± standard error) (32.68±14.55µg/g), followed by Insect Shield® (23.35±2.71µg/g) and lab-created 4g/L permethrin (8.7±0.78µg/g). SPC (after 1000 rubs on MAPT) for Insect Shield®, Sawyer, and 4g/L permethrin groups was significantly lower than TPC (P=0.011, P<0.001, and P=0.001, respectively). The SPC/TPC relationship varied widely between permethrin treatment methods and practical implications for this are discussed. Mosquito repellency tests indicate that Insect Shield®, Sawyer, and lab-created (4g/L) permethrin-treated fabrics showed a significantly higher repellency rate than control (untreated) fabrics (P=0.001, P<0.0001, P<0.0001, respectively). While Insect Shield® had the highest repellency rate against susceptible (53%) and exposed (48%) mosquitoes, differences between groups were not significant. Repellency rates indicate SPC plus other factors (e.g. treatment method) may contribute to mosquito repellency and should be considered in risk assessments for protection against pests.

Operational Insights Into Mosquito Control Disaster Response in Coastal North Carolina: Experiences With the Federal Emergency Management Agency After Hurricane Florence

Preparation for post-hurricane mosquito control is essential for an effective emergency response to protect public health and promote recovery efforts. Effective pre-hurricane planning includes laying the groundwork for a successful reimbursement application to the Federal Emergency Management Agency. The critical and overlapping need to sustain funding for mosquito control programs is highlighted here in the context of both normal and emergency responses. Community support is an integral component of an effective integrated pest management program and is established over time with appropriate communication and engagement. Experienced mosquito control operators who are familiar with treatment areas are an essential component of successful operations. Here, practical advice is provided to plan, prepare, and implement a successful ground- and aerial-based mosquito control response.

Racial and Gender Diversity Among Students and Faculty in EHAC-Accredited Environmental Health Sciences Programs: Trend Analysis from 2009 to 2021

Diversity in the environmental health sciences (EHS) workforce is crucial in providing culturally sensitive services to diverse communities. This may be influenced by academic faculty training a diverse student body in the field of environmental health. This study aimed to characterize the diversity of students and faculty in EHS programs accredited by the National Environmental Health Science and Protection Accreditation Council (EHAC). A retrospective analysis was conducted on secondary data obtained from annual surveys administered to program directors in EHAC-accredited academic programs that included both undergraduate and graduate EHS degrees. The database covered surveys on gender and race that were conducted by EHAC for 12 academic years spanning 2009-2010 to 2020-2021. Results show most students (undergraduate and graduate) were female (54.4% and 52.1%, respectively) and white (61.0% and 50.7%, respectively). Increasing trends were observed over the last 12 years (2009-2021) in female undergraduate (from 53.7% to 59.8%) and graduate (from 47.1% to 60.3%) students and in non-white undergraduate students (from 40.0% to 48.2%). Most faculty (teaching in undergraduate and graduate programs) were male (64.4% and 64.3%, respectively) and white (77.9% and 92.1%, respectively). Increasing trends were observed from 2009 to 2021 in female faculty teaching undergraduate (from 27.7% to 42.2%) and graduate (from 31.3% to 42.1%) students. Native American, Alaska Native, Native Hawaiian, and Pacific Islander are consistently the most underrepresented racial groups in both undergraduate and graduate students and faculty. This study provides baseline data on the diversity of students and faculty in EHAC-accredited programs, which is important in informing future research and efforts to increase such diversity. Gender and racial disparity in EHS students and faculty needs to be addressed to provide necessary support to women and non-White constituents by institutional change in culture through active recruitment and by stronger collaboration between professional organizations and minority groups.

Assessing Durability and Safety of Permethrin Impregnated Uniforms Used by Outdoor Workers to Prevent Tick Bites after One Year of Use

Long lasting permethrin-impregnated (LLPI) clothing can retain permethrin and repel ticks for up to three months and without exceeding EPA-approved safe levels; however, little is known about longer term effects of wearing LLPI clothing. Here, permethrin content was measured in new forester pants soon after initial impregnation (Insect Shield) and again one year later after being repeatedly worn by foresters in the field. Urine samples were collected from foresters for biomonitoring of permethrin metabolites at multiple time intervals (pre-use, one-month, three-to-four-months, and one-year post-use). Lethality against nymphal Ixodes scapularis Say was measured in clothing after one year of wear by foresters. Furthermore, to test potential variability in permethrin impregnation of different batches of clothing, separate sets of clothing were anonymously sent to Insect Shield for permethrin treatment over a period of three months and permethrin was quantified. Results demonstrated 33% of participants' pants had no measurable permethrin after one year of wear and permethrin content and tick mortality varied significantly between clothing. Only two of the participants' clothing resulted in ≥ 30% tick mortality after one year of wear. Significant differences were observed in 3-PBA and trans-DCCA, but not cis-DCCA metabolites in participants over the four measured time points and were higher than general United States population levels. This study provides practical information on the safety (measured by urinary metabolites) over time of LLPI clothing. It also provides snapshots (pre-washing and after one year of wear) of effectiveness of LLPI clothing as personal protective equipment against ticks for outdoor workers.

Facebook and mosquito-borne disease outbreaks: An analysis of public responses to federal health agencies' posts about dengue and Zika in 2016

Responses of Facebook users to four United States federal health agencies' social media posts about dengue and Zika (mosquito-borne diseases), surveillance, and control during the Zika outbreak in 2016 were tracked. Official Facebook pages of health agencies were analyzed, and a qualitative analysis program was used to perform a thematic analysis of the data on public responses to health agency posts. Public sentiment analysis showed that Facebook users had a negative sentiment towards health information observed in this study. Themes were identified in the studied posts, giving insight into the nature of public discussions and responses to federal health agencies. Themes were assessed based on the way the agencies' mosquito-borne disease information was received by the public through the social media platform, Facebook. Results indicate that public perception/understanding of mosquito-borne disease outbreaks can be assessed by analyzing public interactions with health agencies on Facebook. The importance of maximizing effectiveness by addressing issues in sharing health education information, risk communication, and monitoring of public responses by health agencies through social media platforms is discussed.

Mosquito-infecting virus Espirito Santo virus inhibits replication and spread of dengue virus

The primary vector of dengue virus (DENV) is Aedes aegypti. The mosquito-infecting virus, Espirito Santo virus (ESV), does not infect Vero (mammalian) cells and grows in mosquito (C6/36) cells without cytopathic effects. Effects of ESV infection on replication of DENV were explored in vitro and in vivo, analyzing protein, RNA genome expression, and plaque formation. ESV and DENV simultaneous coinfection did not block protein synthesis from either virus but did result in inhibition of DENV replication in mosquito cells. Furthermore, ESV superinfected with DENV resulted in inhibition of DENV replication and spread in A. aegypti, thus reducing vector competence. Tissue culture experiments on viral kinetics of ESV and DENV coinfection showed that neither virus significantly affects the replication of the other in Vero, HeLa, or HEK cells. Hence, ESV blocks DENV replication in insect cells, but not the mammalian cells evaluated here. Our study provides new insights into ESV-induced suppression of DENV, a globally important pathogen impacting public health.

Assessment of Resistance to Organophosphates and Pyrethroids in Aedes aegypti (Diptera: Culicidae): Do Synergists Affect Mortality?

Aedes aegypti (L.) is the primary vector of Zika, dengue, yellow fever, and chikungunya viruses. Insecticides used in mosquito control can help prevent the spread of vector-borne diseases. However, it is essential to determine insecticide resistance (IR) status before control measures are undertaken. Only the most effective insecticides should be used to avoid ineffective control and/or promotion of IR. Pyrethroids and organophosphates are the most commonly used insecticides for mosquito control. Here, the efficacy of two active ingredients (AIs; permethrin [pyrethroid], chlorpyrifos [organophosphate]), two formulated products (FPs; Biomist [AI: permethrin]) and (Mosquitomist [AI: chlorpyrifos]), and three synergists (piperonyl butoxide, diethyl maleate, S-S-S-tributyl phosphorotrithioate) was evaluated in two Ae. aegypti colonies (pyrethroid resistant and susceptible). Mosquitomist was most effective against the pyrethroid-resistant colony (100% mortality at diagnostic time). Pre-exposure to synergists did not increase the efficacy of AIs against the pyrethroid-resistant colony. Further research is needed to discover how synergists may affect the efficacy of insecticides when used on pyrethroid-resistant mosquitoes.

Vector-borne Diseases and Climate Change: North Carolina's Policy Should Promote Regional Resilience

Emerging and endemic vector-borne diseases remain significant causes of morbidity and economic burden in North Carolina. Effective policies must promote climate change resilience through public health preparedness at local and regional scales to proactively address the diverse environmental, climatic, and demographic factors amplifying vector-borne disease risk.

Short-Term, Large-Area Survey of Container Aedes spp. (Diptera: Culicidae): Presence and Abundance is Associated with Fine-scale Landscape Factors in North Carolina, USA

Container Aedes mosquitoes are responsible for the transmission of anthroponotic and zoonotic viruses to people. The surveillance and control of these mosquitoes is an important part of public health protection and prevention of mosquito-borne disease. In this study, we surveyed 327 sites over 2 weeks in late June and early July in 2017 in North Carolina, USA for the presence and abundance of Aedes spp. eggs in an effort to better target potential Ae. aegypti collections. We examined the ability of 2 types of landscape data, Light Detection And Ranging (LIDAR) and National Land Cover Database (NLCD) to explain the presence and abundance of eggs using principal component analysis to deal with collinearity, followed by generalized linear regression. We explained variation of both egg presence and abundance for Aedes albopictus (Skuse) and Aedes triseriatus (Say) using both NLCD and LIDAR data. However, the ability to make robust predictions was limited by variation in the data. Increased sampling time and better landscape data would likely improve the predictive ability of our models, as would a better understanding of oviposition behavior.

Assessing Insecticide Resistance in Adult Mosquitoes: Perspectives on Current Methods

Mosquito insecticide resistance (IR) is a growing global issue that must be addressed to protect public health. Vector control programs (VCPs) should regularly monitor local mosquito populations for IR and plan control measures accordingly. In some cases, state/federal resources financially support this testing with expertise and/or training programs. Standardization of methods (eg, Centers for Disease Control and Prevention bottle bioassay, World Health Organization tube testing, dose-mortality bioassay) for monitoring IR must be prioritized. One solution is regional hubs of IR monitoring at the state or other level. Training programs on methodology and interpretation of results should be developed and routinely offered to local VCPs conducting IR testing in mosquitoes. Here, current methods for assessing mosquito IR are discussed and insights into a variety of questions from VCPs are considered. It is critical that methods for IR monitoring and data interpretation are standardized through routine training, with the goal of evidence-driven decision making to improve control of mosquitoes and mosquito-borne disease.

Context-Dependent Accuracy of the BG-Counter Remote Mosquito Surveillance Device in North Carolina

There is a clear need for improved vector surveillance approaches that are affordable, labor efficient, and safer than traditional methods. The BG-Counter (Biogents USA, Moorefield, WV) is a device for remotely monitoring mosquito activity in combination with the BG-Sentinel (Biogents USA), a widely used trap for the collection of host-seeking mosquitoes. The BG-Counter uses a wireless connection to provide real-time counts of mosquitoes captured by the BG-Sentinel, allowing users to remotely monitor mosquito populations. This study tested the effectiveness of the BG-Counter in 5 North Carolina counties. A total of 96 trap-days resulted in the collection of >45,000 individual mosquitoes representing 35 species. Aedes albopictus was the most common species collected in all counties, except for New Hanover County where Culex nigripalpus was the most common. The mean daily accuracy ranged from 80.1% (New Hanover County) to 9.4% (Jackson County). There was a significant linear relationship between the actual number of mosquitoes collected and the device counts at all sites except Jackson County, the site with the lowest relative mosquito abundance compared with nontarget organisms. A linear regression of daily BG-Counter accuracy and the daily proportion of mosquitoes to the total number of arthropods collected revealed a significant positive linear relationship, supporting the premise that the BG-Counter is less effective when the relative abundance of mosquitoes is low. Mosquito surveillance programs using the BG-Counter should recognize its context-dependent accuracy and routinely evaluate the accuracy of the device based on local conditions.

Impact of the Insect Growth Regulator Pyriproxyfen on Immature Development, Fecundity, and Fertility of Aedes albopictus

Aedes albopictus is a vector of several arboviruses; however, control of this day-active species is difficult with ultra-low-volume insecticide treatments applied at dusk/dawn periods. In the current laboratory study, blood-fed Ae. albopictus were exposed to Archer^® (insect growth regulator AI: pyriproxyfen) residue in glass bottles (to approximate barrier treatment) and allowed to oviposit. Control mosquitoes were exposed to clean bottles. To evaluate potential dilution effects of water volume, mosquitoes were allowed to oviposit in (relatively) small (59 ml water) or large (177 ml water) containers. The extent to which fecundity (number of eggs laid), fertility rate (number of larvae hatched/number of eggs laid × 100), and emergence rate (number of adults emerged/number of larvae hatched × 100) differed between groups was characterized. In the control group, 18-21 (82-95%) mosquitoes laid eggs, while only 10-11 (45-50%) of mosquitoes in the pyriproxyfen group laid eggs. These sample sizes should be considered when comparing results to other studies. Significantly lower (P = 0.0008) fecundity was observed in mosquitoes exposed to pyriproxyfen (mean ± SE) (small container: 25.2 ± 7.1, large container: 24.3 ± 7.1) compared to control mosquitoes (small container: 49.2 ± 7.8, large container: 52.7 ± 5.2). Regardless of treatment, no significant differences in fecundity were observed between mosquitoes allowed to oviposit in different-sized containers. Hatch rate was significantly lower in the pyriproxyfen group and was impacted by container size (P = 0.032) and treatment (P < 0.0001) (large, control: 61.9% ± 7.8; small, control: 38.0% ± 7.1; large, treated: 10.3% ± 2.4; small, treated: 2.9% ± 1.9). Adult emergence rates were not significantly impacted by treatment or container size. Pyriproxyfen applied as a barrier treatment may be an effective tool for controlling Ae. albopictus.

A Review of Studies Evaluating Insecticide Barrier Treatments for Mosquito Control From 1944 to 2018

BACKGROUND AND PURPOSE

Barrier insecticide treatments have a long history in mosquito control programs but have been used more frequently in the United States in recent years for control of invasive "backyard" species (eg, Aedes albopictus) and increases in incidence of vector-borne diseases (eg, Zika).

METHODS

We reviewed the published literature for studies investigating barrier treatments for mosquito control during the last 74 years (1944-2018). We searched databases such as PubMed, Web of Science, and Google Scholar to retrieve worldwide literature on barrier treatments.

RESULTS

Forty-four studies that evaluated 20 active ingredients (AIs) and 21 formulated products against multiple mosquito species are included. Insecticides investigated for efficacy included organochlorines (dichlorodiphenyltrichloroethane [DDT], β-hexachlorocyclohexane [BHC]), organophosphates (malathion), and pyrethroids (bifenthrin, deltamethrin, permethrin, lambda-cyhalothrin) as AIs. Study design varied with multiple methods used to evaluate effectiveness of barrier treatments. Barrier treatments were effective at lowering mosquito populations although there was variation between studies and for different mosquito species. Factors other than AI, such as exposure to rainfall and application equipment used, also influenced control efficacy.

CONCLUSIONS

Many of the basic questions on the effectiveness of barrier insecticide applications have been answered, but several important details still must be investigated to improve precision and impact on vector-borne pathogen transmission. Recommendations are made to assist future evaluations of barrier treatments for mosquito control and to limit the potential development of insecticide resistance.

Evaluation of Insecticide Resistance in Aedes albopictus (Diptera: Culicidae) in North Carolina, 2017

Mosquitoes may develop resistance to insecticide active ingredients (AIs) found in formulated products (FPs) due to environmental exposure from insecticides in mosquito control and/or unrelated to mosquito control, e.g., agricultural, household pest control. Mosquito control programs should implement resistance management strategies by assessing resistance in targeted populations, rotating different classes of insecticides based on resistance testing, and/or increasing insecticide concentration (i.e., saturation, using maximum labeled rate) to overcome emerging resistance. Resistance testing is often done solely on AIs, but should, in some cases, include both AIs and FPs at the concentrations mosquitoes may encounter in the field. The resistance/susceptibility status was determined for adulticides used in mosquito control. Centers for Disease Control and Prevention (CDC) bottle bioassays were used to assess resistance/susceptibility status for eight AIs (i.e., bifenthrin, permethrin, sumethrin/prallethrin, deltamethrin, tau-fluvalinate, chlorpyrifos, malathion, and naled) and eight FPs (TalStar, Biomist 3 + 15, Duet, Suspend Polyzone, Mavrik, MosquitoMist, Fyfanon, and Dibrom) that respectively contain the AIs. Current CDC guidelines were utilized: susceptible (97-100% mortality at diagnostic time [DT]), developing resistance (90-96% mortality at DT), or resistant (<90% mortality at DT). Significant differences were observed in mosquito susceptibility/resistance among and between AIs and FPs.

Evaluation of Barrier Sprays for Controlling Mosquitoes in Eastern North Carolina: Can Land Cover and Spatial Analyses Improve Predictions of Efficacy?

Mosquitoes can be a nuisance and can transmit pathogens causing numerous diseases. Homeowners may hire private companies that use barrier sprays to alleviate mosquito-related issues, especially in areas where government funding for mosquito control programs is limited. Here, the spatial distribution of mosquitoes was evaluated in a suburban neighborhood during successive treatments with either Bifen Insecticide/Termiticide (active ingredient: bifenthrin) or Suspend Polyzone (active ingredient: deltamethrin) from May 17 to November 8, 2016. A total of 15,083 adult mosquitoes and 18,054 mosquito eggs were collected. Analysis of variance (P < 0.05) was used to analyze differences in abundance of key species between weeks, traps, and treatments. Weather trends were analyzed in relation to mosquito abundance using time-lagged weekly average temperatures and total rainfall. Kriging showed hot spots of mosquito abundance. The spatial pattern of abundance was different for oviposition and adults, and this was expected because of different types of traps used here. A land cover analysis was performed within the geographic information system (GIS) file to determine the extent to which land cover type could predict mosquito abundance. We show an uneven distribution of host-seeking mosquito abundance and that, in general, mosquitoes preferred areas that were lightly wooded or composed of small collections of trees or bushes, compared with larger densely wooded areas. Analyses of spatial distribution, land cover, and weather can be used to supplement an integrated mosquito management approach.

A Statewide Survey of Container Aedes Mosquitoes (Diptera: Culicidae) in North Carolina, 2016: A Multiagency Surveillance Response to Zika Using Ovitraps

Native and invasive container-inhabiting Aedes mosquitoes (Diptera: Culicidae) play important roles in the transmission of endemic and traveler-introduced arboviruses in the United States. In response to the emergence of Zika virus into the Americas, we surveyed the distribution of container Aedes spp. of public health importance within North Carolina during 2016 using ovitraps. A seasonal survey was conducted in 18 counties from the mountains to the coast to identify species incriminated in the transmission of chikungunya, dengue, La Crosse, yellow fever, and Zika viruses. Multiple local, state, and federal agencies participated in the study and submitted more than 3,600 ovistrips. Aedes albopictus (Skuse) (81.4%, n = 54,458) was the most common and widespread species found in this survey, followed by Aedes triseriatus (Say) (10.7%, n = 7,169) and Aedes japonicus (Theobald) (7.9%, n = 5,262). We did not find Aedes aegypti and rarely found Aedes hendersoni (Cockerell). We assessed broad-scale climatic and other factors and determined that longitude, elevation, rainfall, and temperature had significant effects on explaining the variation in presence, abundance, and phenology of container Aedes in North Carolina. However, much of the variation in these outcomes was not explained at this coarse scale and may benefit from finer-scale analyses. These efforts represent the largest ovitrap survey ever conducted in the state.

Impact of Mosquito Age and Insecticide Exposure on Susceptibility of Aedes albopictus (Diptera: Culicidae) to Infection with Zika Virus

Zika virus (ZIKV) is primarily transmitted to humans by Aedes aegypti and Ae. albopictus. Vector⁻virus interactions influencing vector competence vary and depend on biological and environmental factors. A mosquito's chronological age may impact its immune response against virus infection. Insecticides, source reduction, and/or public education are currently the best defense against mosquitoes that transmit ZIKV. This study assessed the effects of a mosquito's chronological age at time of infection on its response to ZIKV infection. We exposed young (6⁻7 d post-emergence) and old (11⁻12 d post-emergence) Ae. albopictus to a sublethal dose of bifenthrin prior to oral exposure to blood meals containing ZIKV (7-day incubation period). Old mosquitoes experienced a significantly (p < 0.01) higher rate of mortality than young mosquitoes. Significantly higher ZIKV body titers (p < 0.01) were observed in the old control group compared to the young control group. Significantly higher (p < 0.01) ZIKV dissemination rates and leg titers (p < 0.01) were observed in old bifenthrin-exposed mosquitoes compared to old control mosquitoes or young bifenthrin-exposed or control mosquitoes. Hence, bifenthrin exposure may increase the potential for virus transmission; however, the degree of these impacts varies with mosquito age. Impacts of insecticides should be considered in risk assessments of potential vector populations.

Insecticide Susceptibility Screening Against Culex and Aedes (Diptera: Culicidae) Mosquitoes From the United States

Mosquitoes exposed to sublethal doses of insecticides may be selected for resistance to insecticide active ingredients (AIs). Mosquitoes are exposed to AIs through agricultural, public/private mosquito control programs, homeowners, and other sources. Hence, mosquito control programs should routinely measure the resistance/susceptibility status of mosquito populations of public health concern. The objectives here were to determine resistance status for six AIs used in adult mosquito control in the United States to assess how resistance/susceptibility differs between AI, mosquito species (states where > 1 species collected), and between years (some populations sampled for 2 yr). Field-collected eggs from 21 mosquito populations of six different species or hybrid species (Aedes albopictus Skuse [Diptera: Culicidae], Aedes aegypti L. [Diptera: Culicidae], Culex nigripalpus Theobald, Culex pipiens L. [Diptera: Culicidae], Culex quinquefasciatus Say [Diptera: Culicidae], Cx. pipiens/quinquefasciatus) were obtained. Centers for Disease Control and Prevention bottle bioassays were used to assess the resistance/susceptibility status for six AIs (bifenthrin, deltamethrin, etofenprox, malathion, permethrin, and phenothrin). World Health Organization guidelines were used to classify mosquitoes as susceptible (98-100% mortality at diagnostic time [DT]), possibly resistant (80-97% mortality at DT), or resistant (<80% mortality at DT). Significant differences were observed in mosquito susceptibility/resistance between species and AIs. In states where both Aedes and Culex were collected, the odds of exhibiting resistance in Culex were 68-69 times higher than Aedes (Texas odds ratio: 69.30; 95% confidence interval: 5.86, 819.44; P = 0.001; North Carolina odds ratio: 67.99; 95% confidence interval: 15.21, 303.94; P < 0.0001). Some level of resistance was detected against all tested AIs in several mosquito populations and some varied between 2015 and 2016.

Permethrin treated clothing to protect outdoor workers: evaluation of different methods for mosquito exposure against populations with differing resistance status

Minimizing arthropod exposure (e.g. mosquito and tick bites) is vital to protect health of outdoor workers. Personal protective measures can help protect against exposure. Here, the quantity of permethrin was evaluated for different fabric types after washing. Cone and petri dish exposure assays were used to investigate the knockdown/mortality of permethrin-susceptible and permethrin-resistant populations of mosquitoes. Permethrin-treated clothing was effective against the tested mosquito population that was susceptible to permethrin but not a permethrin-resistant population. Permethrin quantity was significantly highest in the 100% cotton fabric and for the 0 wash group. Permethrin quantity in fabrics decreased with washing. No significant differences (p > 0.05) were observed in knockdown/mortality rates for either exposure method. The protective effect of permethrin-treated clothing against mosquitoes is impacted by many factors, e.g. wash frequency, fabric type, and the susceptibility/resistance status of local mosquito populations.

Regional Survey of Mosquito Control Knowledge and Usage In North Carolina

Mosquitoes are a nuisance and can transmit pathogens to humans and other animals, resulting in notable morbidity and mortality. Organized mosquito control programs conduct surveillance, source reduction, treatment of mosquito oviposition sites, and adulticiding to protect public health. However, in some regions, there has been a decline in county and municipal mosquito control programs, and homeowners increasingly contract with private mosquito control companies or address mosquito-related issues themselves at the household level. The extent to which these services are being used, the potential for mosquito and/or insecticide exposure around the home, and the access to these services by individuals of different socioeconomic categories are not known. We conducted regional (western, central, eastern) assessments of public perception and knowledge of mosquito control services in a variety of communities of different socioeconomic categories (low, moderate, high) and types (urban, suburban, rural) in 3 North Carolina counties. We also assessed the respondents' basic knowledge of mosquito-borne diseases. Most respondents thought mosquito control was important to protect against both nuisance mosquitoes and mosquito-borne disease. The majority of people would pay ≤$50/year for mosquito control and most thought this should be covered by municipal/county taxes. Many respondents (31%, 95% confidence interval [CI] 26-35%) personally undertake mosquito control on their properties, but only 5.3% (95% CI 3.1-7.5%) contract with professional mosquito control services, with no significant differences between region, community type, or socioeconomic category in the proportion using private mosquito control services. While there were significant differences between factor levels (3 regions, 3 community types, 3 socioeconomic categories) in some responses, there were no significant differences observed between respondents, regardless of factor level, in the willingness to contribute funds to a community-based mosquito control program.

Evaluation of Bifenthrin and Deltamethrin Barrier Sprays for Mosquito Control in Eastern North Carolina

Mosquitoes are a nuisance and potentially transmit pathogens causing numerous diseases worldwide. Homeowners and others may hire private companies to alleviate mosquito-related issues. Here, two pyrethroids (Suspend Polyzone [deltamethrin] and Bifen Insecticide/Termiticide [bifenthrin]) were evaluated on properties in North Carolina for 23 wk from 18 May through 19 October 2015. Properties were treated using backpack mist blowers every 21 d. At 17 fixed sampling locations, Centers for Disease Control and Prevention carbon dioxide-baited traps were deployed overnight once/week for the duration of the experiment. Oviposition traps were deployed weekly at the same locations. Differences were observed in mosquito abundance between neighborhoods, treatments, and weeks and differences varied between species. Mosquito abundance was generally significantly higher in traps placed on control properties (no insecticide) compared to traps placed on treatment properties. Bifenthrin and deltamethrin showed differences from each other in efficacy, but this varied between neighborhoods and species. Future studies could test the efficacy of barrier sprays at different application frequencies and/or in conjunction with weather monitoring. Coupled with regular mosquito surveillance and using integrated pest management principles, barrier sprays can be an effective tool for suppression of mosquito populations.

Potential for sublethal insecticide exposure to impact vector competence of Aedes albopictus (Diptera: Culicidae) for dengue and Zika viruses

Chikungunya, dengue, and Zika viruses (CHIKV, family Togaviridae, genus Alphavirus; DENV and ZIKV, family Flaviviridae, genus Flavivirus) are arboviruses that cause human epidemics. Due to the lack of vaccines for many mosquito-borne diseases, there is a need for mosquito control. In the US and other regions, residual barrier insecticide sprays are applied to foliage where female mosquitoes rest and/or sugar feed between blood meals. Residual sprays are an important control method for anthropogenic day-active sylvan mosquitoes such as Aedes albopictus (vector of CHIKV, DENV, and ZIKV) that are difficult to control using ultralow-volume sprays applied only at dusk or dawn when these mosquitoes are not active. In this exploratory study, we analyzed the extent to which ingestion of a sublethal dose of the active ingredient bifenthrin affected vector competence (i.e., infection, dissemination, and transmission) of Ae. albopictus for DENV and ZIKV. Two incubation periods (IPs; 7 and 14 d) were tested at 28°C for insecticide-fed and sugar-fed mosquitoes. We show that mosquitoes that were fed bifenthrin (0.128 µg/mL) mixed with sucrose solution exhibited significantly lower DENV infection rates and body titers after a 14-d IP. During the 7-d IP, one mosquito (sugar group) transmitted ZIKV. During the 14-d IP, 100% of mosquitoes showed body and leg ZIKV infections, and one mosquito (sugar+bifenthrin group) transmitted ZIKV. This is a preliminary communication, and more studies will be required to further investigate these findings. We expect the findings of this small-scale study to spur larger-scale investigations of the impacts of insecticides on mechanisms regulating vector competence, and exposure to other active ingredients, and aid in development of new insecticides.

Baseline Insecticide Susceptibility Screening Against Six Active Ingredients for Culex and Aedes (Diptera: Culicidae) Mosquitoes in the United States

Mosquitoes may develop resistance to insecticide active ingredients (AI). Thus, mosquitoes should be tested for resistance to confirm efficacy of insecticide-based control, inform management decisions, and protect public and environmental health. Our objectives were to determine a baseline of resistance for six AIs used in mosquito control in the United States to assess how resistance differs between mosquito collection location, AI, and mosquito species (container-ovipositing Aedes and Culex that may oviposit in containers or other sources). Field-collected eggs from 26 mosquito populations of five different species or hybrid species (Aedes albopictus Say, Aedes triseriatus Say, Culex pipiens L., Culex quinquefasciatus Say, Culex pipiens/quinquefasciatus) were obtained from four regions across the United States. Centers for Disease Control and Prevention bottle bioassays were used to determine baseline resistance and susceptibility status for six AIs (bifenthrin, deltamethrin, etofenprox, malathion, permethrin, and phenothrin). World Health Organization guidelines were used to classify mosquitoes as susceptible (98-100% mortality at diagnostic time [DT]), possibly resistant (80-97% mortality at DT), or resistant (< 80% mortality at DT). Aedes spp. mosquitoes were less likely to exhibit resistance, compared with Culex spp. mosquitoes. A high degree of resistance to etofenprox and malathion was observed (4-26-fold greater resistance to these two AIs compared with the other examined AIs). Baseline data on resistance and susceptibility for mosquitoes exposed to commonly used insecticides may help us evaluate resistance trends and highlight the importance of assessing local resistance trends before insecticide-based control measures are implemented.

Residual Effectiveness of Permethrin-Treated Clothing for Prevention of Mosquito Bites Under Simulated Conditions

Biological hazards such as exposure to ticks and mosquitoes can affect health. Permethrin-treated clothing is available to the public. We don’t currently understand, however, the effects of environmental factors such as fabric type, washing, sunlight, and temperature on permethrin content in treated clothing with respect to mosquito knockdown and mortality. We evaluated the extent to which fabric type (100% cotton denim jeans, 100% polyester work shirt, 35% cotton/65% polyester work shirt), light exposure (0 or 100%), temperature (18 °C, 32 °C), and number of washes (0, 3, 12, 36) affected mosquito knockdown 2 hours post-exposure, mosquito mortality 24 hours post-exposure, and permethrin content. All fabrics used in this study were treated with permethrin at a concentration of 125 µg/cm2. Denim fabric having no washes and no light exposure showed the highest amount of permethrin. Washing and light exposure significantly reduced the ability of permethrin-treated fabrics to induce mosquito knockdown and/or mortality under the simulated conditions used for this test. Temperatures tested did not affect permethrin content or mosquito knockdown and mortality. Long-lasting impregnation of uniforms protects against mosquito bites under simulated laboratory conditions. Employers and employees should consider the use of permethrin-impregnated clothing and uniforms in addition to daily repellent sprays.

Evaluation of bifenthrin barrier spray on foliage in a suburban eastern North Carolina neighborhood

BACKGROUND

Mosquitoes can transmit pathogens through blood feeding. Mosquito control programs conduct surveillance and source reduction, treat mosquito oviposition sites and spray adulticides to protect public health. In some areas, homeowners may contract with private mosquito control companies to address mosquito-related issues.

RESULTS

We evaluated the efficacy of barrier sprays by comparing weekly host-seeking mosquito abundance at treatment and control properties in a residential neighborhood. The chemical concentration of bifenthrin residue on foliage was quantified, and field-collected mosquitoes, primarily Aedes albopictus, were tested for bifenthrin resistance using bottle bioassays. Mosquito abundance at treatment properties was significantly (P < 0.05) lower than at control properties. Quantities of bifenthrin detected on foliage from treatment properties was not correlated with mosquito abundance. No bifenthrin resistance was detected in captured mosquitoes.

CONCLUSION

Based on the rate of application, we expected that chemical analysis of bifenthrin residue would show similar concentrations of bifenthrin on foliage in treatment areas. Although mosquitoes were not bifenthrin resistant, further studies are needed to evaluate the extent to which resistance changes over time with repeated applications. Findings from this study provide insight into control methods commonly used by mosquito control companies and could potentially be used to guide future mosquito management strategies.

Aptamer based peptide enrichment for quantitative analysis of gonadotropin-releasing hormone by LC-MS/MS

Over recent years threats to racing have expanded to include naturally occurring biological molecules, such as peptides and proteins, and their synthetic analogues. Traditionally, antibodies have been used to enable detection of these compounds as they allow purification and concentration of the analyte of interest. The rapid expansion of peptide-based therapeutics necessitates a similarly rapid development of suitable antibodies or other means of enrichment. Potential alternative enrichment strategies include the use of aptamers, which offer the significant advantage of chemical synthesis once the nucleic acid sequence is known. A method was developed for the enrichment, detection and quantitation of gonadotropin-releasing hormone (GnRH) in equine urine using aptamer-based enrichment and LC-MS/MS. The method achieved comparable limits of detection (1 pg/mL) and quantification (2.5 pg/mL) to previously published antibody-based enrichment methods. The intra- and inter-assay precision achieved was less than 10% at both 5 and 20 pg/mL, and displayed a working dynamic range of 2.5-100 pg/mL. Significant matrix enhancement (170 ± 8%) and low analytical recovery (29 ± 15%) was observed, although the use of an isotopically heavy labelled GnRH peptide, GnRH (Pro(13)C5,(15)N), as the internal standard provides compensation for these parameters. Within the current limits of detection GnRH was detectable up to 1h post administration in urine and identification of a urinary catabolite extended this detection window to 4h. Based on the results of this preliminary investigation we propose the use of aptamers as a viable alternative to antibodies in the enrichment of peptide targets from equine urine.

Effects of Blood Coagulate Removal Method on Aedes albopictus (Diptera: Culicidae) Life Table Characteristics and Vector Competence for Dengue Virus

Commercially available blood can be used as an alternative to live animals to maintain mosquito colonies and deliver infectious bloodmeals during research studies. We analyzed the extent to which two methods for blood coagulate removal (defibrination or addition of sodium citrate) affected life table characteristics (i.e., fecundity, fertility, hatch rate, and adult survival) and vector competence (infection, dissemination, and transmission) of Aedes albopictus (Skuse) for dengue virus (DENV). Two types of bovine blood were tested at two extrinsic incubation temperatures (27 or 30°C) for DENV-infected and uninfected mosquitoes. Fully engorged mosquitoes were transferred to individual cages containing an oviposition cup and a substrate. Eggs (fecundity) and hatched larvae (fertility) were counted. At 14 and 21 d post feeding on a DENV-infected bloodmeal, 15 mosquitoes were sampled from each group, and vector competence was analyzed (bodies [infection], legs [dissemination], and saliva [transmission]). Differences in life table characteristics and vector competence were analyzed for mosquitoes fed blood processed using different methods for removal of coagulates. The method for removal of coagulates significantly impacted fecundity, fertility, and hatch time in the uninfected group, but not DENV-infected group. Infected mosquitoes showed significantly higher fecundity and faster hatch time than uninfected mosquitoes. We show no significant differences in infection or dissemination rates between groups; however, horizontal transmission rate was significantly higher in mosquitoes fed DENV-infected citrated compared with defibrinated blood. We expect the findings of this study to inform research using artificial blood delivery methods to assess vector competence.

Trends in Dengue Cases Imported into the United States from Pan America 2001-2012

The objective of this study was to improve risk assessments of travel on dengue (DEN) virus (DENV) distribution. We investigated the exposure risk of US citizens traveling to DEN-endemic Pan American countries. The number of DEN cases reported in 51 Pan American countries from 2001 to 2012 was compared to the population of the same countries. The number of US travelers visiting the Pan American countries was categorized by region, and travel-related DEN infections were analyzed. US residents visiting the Dominican Republic exhibited the highest traveler-related DEN incidence. Brazil showed the most DEN cases in its residents (>1 million reported cases in 2010). The number of DEN cases continues to rise as does international travel and the geographic range of potential DENV vectors. DENV risk assessments may be improved by analyzing the possible routes of entry. Underreporting remains an issue for calculating DENV transmission risk by country and region.

Susceptibility of Florida Aedes aegypti and Aedes albopictus to dengue viruses from Puerto Rico

Locally acquired dengue cases in the continental U.S. are rare. However, outbreaks of dengue-1 during 2009, 2010, and 2013 in Florida and dengue-1 and -2 in Texas suggest vulnerability to transmission. Travel and commerce between Puerto Rico and the U.S. mainland is common, which may pose a risk for traveler-imported dengue cases. Mosquitoes were collected in Florida and used to evaluate their susceptibility to dengue viruses (DENV) from Puerto Rico. Aedes aegypti and Ae. albopictus were susceptible to virus infection with DENV-1 and -2. No significant differences were observed in rates of midgut infection or dissemination between Ae. aegypti or Ae. albopictus for DENV-1 (6-14%). Aedes aegypti was significantly more susceptible to midgut infection with DENV-2 than Ae. albopictus (Ae. aegypti, ∼28%; Ae. albopictus, ∼9%). The dissemination rate with dengue-2 virus for Ae. aegypti (23%) was greater than Ae. albopictus (0%), suggesting that Ae. albopictus is not likely to be an important transmitter of the DENV-2 isolate from Puerto Rico. These results are discussed in light of Florida's vulnerability to DENV transmission.

Emergency mosquito control on a selected area in eastern north Carolina after hurricane irene

Natural disasters such as hurricanes may contribute to mosquito abundance and, consequently, arbovirus transmission risk. In 2011, flooding from Hurricane Irene in eastern North Carolina (NC) resulted in increased mosquito populations that hindered recovery efforts. Budget shortfalls in NC have reduced the functionality of long-term mosquito surveillance and control programs; hence, many counties rely on the Federal Emergency Management Agency for post-disaster mosquito control. This pilot study examines mosquito abundance pre- and post-aerial insecticide spraying at eight study sites in Washington and Tyrrell Counties in rural eastern NC after Hurricane Irene. Percent change was calculated and compared for traps in areas that received aerial pesticide application and those that did not. Traps in spray zones show decreases in mosquito abundance when compared to control traps (treatment: -52.93%; control: 3.55%), although no significant differences (P = 0.286) were found in mosquito abundance between groups. Implications of reactive rather than proactive mosquito control responses are discussed.

Effectiveness of permethrin-treated clothing to prevent tick exposure in foresters in the central Appalachian region of the USA

Outdoor workers are at risk from mosquito and tick bites and the extent to which exposures are linked to vector-borne disease is not understood. This pilot study characterizes for ester exposure to mosquitoes and ticks, and assesses effectiveness of permethrin-treated clothing for prevention of tick bites. Foresters (N = 34) from Kentucky, North Carolina, Ohio, Tennessee, Virginia, and West Virginia were placed into treatment (permethrin-treated clothing) or control (untreated clothing) groups. Foresters completed questionnaires about work-related tick/mosquito exposure and 454 ticks were collected/identified from May to June 2013. A time-weighted analysis based on information submitted by foresters about time working outdoors showed that control participants received a lower rate of tick exposure (0.15 tick bites/hour; 13 bites/person) compared to treatment participants (0.27 bites/hour; 21 bites/person). However, more control participants (85 %) received at least one tick bite compared to treatment participants (52 %). Outdoor workers should be aware of available protective measures, such as permethrin-treated clothing, that may mitigate occupational risks.

BSL-3 laboratory practices in the United States: comparison of select agent and non-select agent facilities

New construction of biosafety level 3 (BSL-3) laboratories in the United States has increased in the past decade to facilitate research on potential bioterrorism agents. The Centers for Disease Control and Prevention inspect BSL-3 facilities and review commissioning documentation, but no single agency has oversight over all BSL-3 facilities. This article explores the extent to which standard operating procedures in US BSL-3 facilities vary between laboratories with select agent or non-select agent status. Comparisons are made for the following variables: personnel training, decontamination, personal protective equipment (PPE), medical surveillance, security access, laboratory structure and maintenance, funding, and pest management. Facilities working with select agents had more complex training programs and decontamination procedures than non-select agent facilities. Personnel working in select agent laboratories were likely to use powered air purifying respirators, while non-select agent laboratories primarily used N95 respirators. More rigorous medical surveillance was carried out in select agent workers (although not required by the select agent program) and a higher level of restrictive access to laboratories was found. Most select agent and non-select agent laboratories reported adequate structural integrity in facilities; however, differences were observed in personnel perception of funding for repairs. Pest management was carried out by select agent personnel more frequently than non-select agent personnel. Our findings support the need to promote high quality biosafety training and standard operating procedures in both select agent and non-select agent laboratories to improve occupational health and safety.

Survival of West Nile virus-challenged Southern house mosquitoes, Culex pipiens quinquefasciatus, in relation to environmental temperatures

We investigated the effect of West Nile virus (WNV) infection on survival in two colonies of Culex pipiens quinquefasciatus Say (Diptera: Culicidae) originating from Vero Beach and Gainesville, FL. Mosquitoes were fed West Nile virus-infected blood and checked daily for survival. Exposure to WNV decreased survival among Cx. p. quinquefasciatus from Gainesville relative to unexposed individuals at 31° C. In contrast, exposure to WNV enhanced survival among Cx. p. quinquefasciatus from Vero Beach relative to unexposed individuals at 27° C. These results may suggest that exposure to WNV and associated infection could increase or decrease components of fitness, dependent on environmental temperature and intraspecific variation in Cx. p. quinquefasciatus. The relationship between lifespan (time of death in days) and WNV titer differed in the colonies at 31° C and 27° C, suggesting that intraspecific species variation in response to temperature impacts interactions with WNV. While further work is needed to determine if similar effects occur under field conditions, this suggests intraspecific variation in vector competence for WNV and adult survival of Cx. p. quinquefasciatus, both aspects of vectorial capacity.