Automated differentiation of mixed populations of free-flying female mosquitoes under semi-field conditions.

Great advances in automated identification systems, or 'smart traps', that differentiate insect species have been made in recent years, yet demonstrations of field-ready devices under free-flight conditions remain rare. Here, we describe the results of mixed-species identification of female mosquitoes using an advanced optoacoustic smart trap design under free-flying conditions. Point-of-capture classification was assessed using mixed populations of congeneric (Aedes albopictus and Aedes aegypti) and non-congeneric (Ae. aegypti and Anopheles stephensi) container-inhabiting species of medical importance. Culex quinquefasciatus, also common in container habitats, was included as a third species in all assessments. At the aggregate level, mixed collections of non-congeneric species (Ae. aegypti, Cx. quinquefasciatus, and An. stephensi) could be classified at accuracies exceeding 90% (% error = 3.7-7.1%). Conversely, error rates increased when analysing individual replicates (mean % error = 48.6; 95% CI 8.1-68.6) representative of daily trap captures and at the aggregate level when Ae. albopictus was released in the presence of Ae. aegypti and Cx. quinquefasciatus (% error = 7.8-31.2%). These findings highlight the many challenges yet to be overcome but also the potential operational utility of optoacoustic surveillance in low diversity settings typical of urban environments.

A decision support tool for risk-benefit analysis of Japanese encephalitis vaccine in travellers.

BACKGROUND: During pre-travel consultations, clinicians and travellers face the challenge of weighing the risks verus benefits of Japanese encephalitis (JE) vaccination due to the high cost of the vaccine, low incidence in travellers (~1 in 1 million), but potentially severe consequences (~30% case-fatality rate). Personalised JE risk assessment based on the travellers' demographics and travel itinerary is challenging using standard risk matrices. We developed an interactive digital tool to estimate risks of JE infection and severe health outcomes under different scenarios to facilitate shared decision-making between clinicians and travellers. METHODS: A Bayesian network (conditional probability) model risk-benefit analysis of JE vaccine in travellers was developed. The model considers travellers' characteristics (age, sex, co-morbidities), itinerary (destination, departure date, duration, setting of planned activities) and vaccination status to estimate the risks of JE infection, the development of symptomatic disease (meningitis, encephalitis), clinical outcomes (hospital admission, chronic neurological complications, death) and adverse events following immunization. RESULTS: In low-risk travellers (e.g. to urban areas for <1 month), the risk of developing JE and dying is low (<1 per million) irrespective of the destination; thus, the potential impact of JE vaccination in reducing the risk of clinical outcomes is limited. In high-risk travellers (e.g. to rural areas in high JE incidence destinations for >2 months), the risk of developing symptomatic disease and mortality is estimated at 9.5 and 1.4 per million, respectively. JE vaccination in this group would significantly reduce the risk of symptomatic disease and mortality (by ~80%) to 1.9 and 0.3 per million, respectively. CONCLUSION: The JE tool may assist decision-making by travellers and clinicians and could increase JE vaccine uptake. The tool will be updated as additional evidence becomes available. Future work needs to evaluate the usability of the tool. The interactive, scenario-based, personalised JE vaccine risk-benefit tool is freely available on www.VaxiCal.com.

Recurrence patterns among patients with sinonasal mucosal melanoma: A multi-institutional study.

OBJECTIVE: To evaluate recurrence patterns and survival after recurrence among patients with sinonasal mucosal melanoma (SNMM). METHODS: This was a multi-institutional retrospective review from seven U.S. institutions of patients with SNMM from 1991 to 2022. Recurrence was categorized as local, regional, distant, or multifocal. Kaplan-Meier tests were used to evaluate disease-free survival (DFS), overall survival (OS), and post-recurrence survival (PRS) reported with standard errors (SE) and log-rank testing used for comparison. Cox-regression was further used, with hazard ratios (HR) and 95% confidence intervals (CI) reported. RESULTS: Among 196 patients with SNMM, there were 146 patients with recurrence (74.5%). Among all patients, 60-month DFS (SE) was 15.5% (2.9%), 60-month OS (SE) was 44.7% (3.7%), mean age ± standard deviation at diagnosis was 69.7 ± 12.5 years, and 54.6% were female. In 26 patients who underwent primary treatment of the neck, 60-month DFS did not differ from no treatment (p > 0.05). Isolated distant recurrence was most common (42.8%), followed by local (28.3%), multifocal (20.7%), and regional recurrence (8.3%). Among patients with regional recurrence in the neck, there was no 60-month PRS benefit for patients undergoing salvage neck dissection or radiation (p > 0.05). Among patients with distant recurrence, only immunotherapy was associated with improved 12-month PRS (HR = 0.32, 95% CI = 0.11-0.92, p = 0.034), and no treatment group was associated with improved 24- or 60-month PRS (p > 0.05). CONCLUSION: SNMM is associated with a high recurrence rate and poor survival. Primary treatment of the neck was not associated with reduced recurrence, and immunotherapy for treatment of distant recurrence was associated with increased 12-month PRS.

Joint FAO/IAEA Coordinated Research Project on "Mosquito Handling, Transport, Release and Male Trapping Methods" in Support of SIT Application to Control Mosquitoes.

Mosquito-borne diseases are among the most important public health problems worldwide [...].

Sinonasal Mucosal Melanoma: Role of Tumor Proliferative Indices and Pathological Factors in Survival.

OBJECTIVE: The objective of this study is to determine the association of proliferation indices and pathologic biomarkers on overall and recurrence/metastasis-free survival (OS and RMFS) in patients with sinonasal mucosal melanoma (SNMM) and to assess the genetic mutational landscape of SNMM. METHODS: This is a retrospective cohort study of 45 SNMM patients without neoadjuvant therapy who underwent surgical therapy with curative intent and had tumor tissue available for histopathologic review, molecular analysis, and genetic mutational assessment. The OS and RMFS were assessed for associations with numerous tumor and patient-related factors. RESULTS: Among proliferative indices, higher Ki67 and mitotic rates were associated with worsened OS and RMFS (Ki67: p = 0.0007 and p < 0.0001; mitotic rate: p = 0.005 and p = 0.0009, respectively). The presence of brisk tumor-infiltrating lymphocytes (TILs) was associated with improved RMFS (p = 0.007) and the presence of lymphovascular invasion was associated with worsened OS and RMFS (p = 0.02 and p = 0.04, respectively). Patients with amelanotic tumors were more likely to have higher T-stage (p = 0.046), less likely to have brisk TILs (p = 0.02) and had worsened RMFS (p = 0.03). Patients on immunotherapy with tumor Ki67 < 40% had better 3-year OS compared to those with higher Ki67 index (p = 0.004). Actionable genetic mutations such as BRAF V600E are rare and present in only 1 of 20 patients tested. CONCLUSION: In SNMM patients, pathologic and proliferation markers such as Ki67, mitotic rate and brisk TILs are associated with survival and may be considered in future staging systems. Clinical response to immunotherapy appears to correlate with the Ki67 index. Given the distinct genetic profile of SNMM, targeted therapies against the MAPK kinase pathway have limited utility. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:2350-2358, 2022.

Modifications to Implanting the OSIA® 2 Bone Conduction Hearing Implant: How I Do it.

This "How I Do It" report describes modifications made to the OSIA bone conduction hearing implant surgery in order to reduce wound complications. Laryngoscope, 132:1850-1854, 2022.

The Use of Automated Traps to Assess the Efficacy of Insecticide Barrier Treatments Against Abundant Mosquitoes in Remote Environments.

Commercially available 'smart' trap technology has not yet been widely used to evaluate interventions against mosquitoes despite potential benefits. These benefits include the ability to capture data continuously at fine temporal scales without the human resources usually required for conventional trap deployment. Here, we used a commercially available smart trap (BG-Counter, Biogents) to assess the efficacy of an insecticide barrier treatment (BiFlex AquaMax) in reducing mosquito nuisance in a logistically challenging coastal environment in Queensland, Australia. Adoption of smart trap technology permitted us to conduct a uniquely detailed assessment of barrier treatments, ultimately allowing us to demonstrate significant reductions in mosquito collections from treated properties over all temporal scales. On average, daily mosquito collections from treated properties were reduced by 74.6% for the duration of the post-treatment period (56 d). This observation was supported by similar reductions (73.3%) in mosquito collections across all hours of the day. It was further found that underlying mosquito population dynamics were comparable across all study sites as evidenced by the high congruence in daily collection patterns among traps (Pearson r = 0.64). Despite limitations related to trap costs and replication, the results demonstrate that smart traps offer new precision tools for the assessment of barrier treatments and other mosquito control interventions.

Mark-release-recapture of male Aedes aegypti (Diptera: Culicidae): Use of rhodamine B to estimate movement, mating and population parameters in preparation for an incompatible male program.

Rapid advances in biological and digital support systems are revolutionizing the population control of invasive disease vectors such as Aedes aegypti. Methods such as the sterile and incompatible insect techniques (SIT/IIT) rely on modified males to seek out and successfully mate with females, and in doing so outcompete the wild male population for mates. Currently, these interventions most frequently infer mating success through area-wide population surveillance and estimates of mating competitiveness are rare. Furthermore, little is known about male Ae. aegypti behaviour and biology in field settings. In preparation for a large, community scale IIT program, we undertook a series of mark- release-recapture experiments using rhodamine B to mark male Ae. aegypti sperm and measure mating interactions with females. We also developed a Spatial and Temporally Evolving Isotropic Kernel (STEIK) framework to assist researchers to estimate the movement of individuals through space and time. Results showed that ~40% of wild females captured daily were unmated, suggesting interventions will need to release males multiple times per week to be effective at suppressing Ae. aegypti populations. Males moved rapidly through the landscape, particularly when released during the night. Although males moved further than what is typically observed in females of the species, survival was considerably lower. These unique insights improve our understanding of mating interactions in wild Ae. aegypti populations and lay the foundation for robust suppression strategies in the future.

The impact of sublethal permethrin exposure on susceptible and resistant genotypes of the urban disease vector Aedes aegypti.

BACKGROUND: In urban environments, some of the most common control tools used against the mosquito disease vector Aedes aegypti are pyrethroid insecticides applied as aerosols, fogs or residual sprays. Their efficacy is compromised by patchy deployment, aging residues, and the evolution and invasion of pyrethroid-resistant mosquitoes. A large proportion of mosquitoes in a given environment will therefore receive sublethal doses of insecticide. The potential impact of this sublethal exposure on the behaviour and biology of Ae. aegypti carrying commonly reported resistance alleles is poorly documented. RESULTS: In susceptible insects, sublethal exposure to permethrin resulted in reductions in egg viability (13.9%), blood avidity (16.7%) and male mating success (28.3%). It caused a 70% decrease in the lifespan of exposed susceptible females and a 66% decrease in the insecticide-resistant females from the parental strain. Exposure to the same dose of insecticide in the presence of the isolated kdr genotype resulted in a smaller impact on female longevity (a 58% decrease) but a 26% increase in eggs per female and a 37% increase in male mating success. Sublethal permethrin exposure reduced host-location success by 20-30% in all strains. CONCLUSION: The detrimental effects of exposure on susceptible insects were expected, but resistant insects demonstrated a less predictable range of responses, including negative effects on longevity and host-location but increases in fecundity and mating competitiveness. Overall, sublethal insecticide exposure is expected to increase the competitiveness of resistant phenotypes, acting as a selection pressure for the evolution of permethrin resistance. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The environmental and ecological determinants of elevated Ross River Virus exposure in koalas residing in urban coastal landscapes.

Koala populations in many areas of Australia have declined sharply in response to habitat loss, disease and the effects of climate change. Koalas may face further morbidity from endemic mosquito-borne viruses, but the impact of such viruses is currently unknown. Few seroprevalence studies in the wild exist and little is known of the determinants of exposure. Here, we exploited a large, spatially and temporally explicit koala survey to define the intensity of Ross River Virus (RRV) exposure in koalas residing in urban coastal environments in southeast Queensland, Australia. We demonstrate that RRV exposure in koalas is much higher (> 80%) than reported in other sero-surveys and that exposure is uniform across the urban coastal landscape. Uniformity in exposure is related to the presence of the major RRV mosquito vector, Culex annulirostris, and similarities in animal movement, tree use, and age-dependent increases in exposure risk. Elevated exposure ultimately appears to result from the confinement of remaining coastal koala habitat to the edges of permanent wetlands unsuitable for urban development and which produce large numbers of competent mosquito vectors. The results further illustrate that koalas and other RRV-susceptible vertebrates may serve as useful sentinels of human urban exposure in endemic areas.

The presence of knockdown resistance mutations reduces male mating competitiveness in the major arbovirus vector, Aedes aegypti.

BACKGROUND: The development of insecticide resistance in mosquitoes can have pleiotropic effects on key behaviours such as mating competition and host-location. Documenting these effects is crucial for understanding the dynamics and costs of insecticide resistance and may give researchers an evidence base for promoting vector control programs that aim to restore or conserve insecticide susceptibility. METHODS AND FINDINGS: We evaluated changes in behaviour in a backcrossed strain of Aedes aegypti, homozygous for two knockdown resistance (kdr) mutations (V1016G and S989P) isolated in an otherwise fully susceptible genetic background. We compared biting activity, host location behaviours, wing beat frequency (WBF) and mating competition between the backcrossed strain, and the fully susceptible and resistant parental strains from which it was derived. The presence of the homozygous kdr mutations did not have significant effects on blood avidity, the time to locate a host, or WBF in females. There was, however, a significant reduction in mean WBF in males and a significant reduction in estimated male mating success (17.3%), associated with the isolated kdr genotype. CONCLUSIONS: Our results demonstrate a cost of insecticide resistance associated with an isolated kdr genotype and manifest as a reduction in male mating success. While there was no recorded difference in WBF between the females of our strains, the significant reduction in male WBF recorded in our backcrossed strain might contribute to mate-recognition and mating disruption. These consequences of resistance evolution, especially when combined with other pleiotropic fitness costs that have been previously described, may encourage reversion to susceptibility in the absence of insecticide selection pressures. This offers justification for the implementation of insecticide resistance management strategies based on the rotation or alternation of different insecticide classes in space and time.

Mosquito-Borne Viruses and Non-Human Vertebrates in Australia: A Review.

Mosquito-borne viruses are well recognized as a global public health burden amongst humans, but the effects on non-human vertebrates is rarely reported. Australia, houses a number of endemic mosquito-borne viruses, such as Ross River virus, Barmah Forest virus, and Murray Valley encephalitis virus. In this review, we synthesize the current state of mosquito-borne viruses impacting non-human vertebrates in Australia, including diseases that could be introduced due to local mosquito distribution. Given the unique island biogeography of Australia and the endemism of vertebrate species (including macropods and monotremes), Australia is highly susceptible to foreign mosquito species becoming established, and mosquito-borne viruses becoming endemic alongside novel reservoirs. For each virus, we summarize the known geographic distribution, mosquito vectors, vertebrate hosts, clinical signs and treatments, and highlight the importance of including non-human vertebrates in the assessment of future disease outbreaks. The mosquito-borne viruses discussed can impact wildlife, livestock, and companion animals, causing significant changes to Australian ecology and economy. The complex nature of mosquito-borne disease, and challenges in assessing the impacts to non-human vertebrate species, makes this an important topic to periodically review.

Patterns of dengue in Nepal from 2010-2019 in relation to elevation and climate.

BACKGROUND: Understanding and describing the regional and climatic patterns associated with increasing dengue epidemics in Nepal is critical to improving vector and disease surveillance and targeting control efforts. METHODS: We investigated the spatial and temporal patterns of annual dengue incidence in Nepal from 2010 to 2019, and the impacts of seasonal meteorological conditions (mean maximum, minimum temperature and precipitation) and elevation on those patterns. RESULTS: More than 25 000 laboratory-confirmed dengue cases were reported from 2010 to 2019. Epidemiological trends suggest that dengue epidemics are cyclical with major outbreaks occurring at 2- to 3-y intervals. A significant negative relationship between dengue incidence and increasing elevation (metres above sea level) driven by temperature was observed (p<0.05) with dengue risk being greatest below 500 m. Risk was moderate between 500 and 1500 m and decreased substantially above 1500 m. Over the last decade, increased nightly temperatures during the monsoon months correlated with increased transmission (p<0.05). No other significant relationship was observed between annual dengue cases or incidence and climatological factors. CONCLUSIONS: The spatial analysis and interpretation of dengue incidence over the last decade in Nepal confirms that dengue is now a well-established public health threat of increasing importance, particularly in low elevation zones and urbanised areas with a tropical or subtropical climate. Seasonal variations in temperature during the monsoon months are associated with increased transmission.

Performance of an aerially applied liquid Bacillus thuringiensis var. israelensis formulation (strain AM65-52) against mosquitoes in mixed saltmarsh-mangrove systems and fine-scale mapping of mangrove canopy cover using affordable drone-based imagery.

BACKGROUND: In the Australian southeast, the saltmarsh mosquito Aedes vigilax (Skuse) is the focus of area-wide larviciding campaigns employing the biological agent Bacillus thuringiensis var. israelensis (Bti). Although generally effective, frequent inundating tides and considerable mangrove cover can make control challenging. Here, we describe the efficacy and persistence of an aqueous Bti suspension (potency: 1200 International Toxic Units; strain AM65-52) within a mixed saltmarsh-mangrove system and the use of affordable unmanned aerial systems (UAS) to identify and map problematic levels of mangrove canopy cover. RESULTS: High mangrove canopy density (>40% cover) reduced product deposition by 75.2% (0.01 ± 0.002 µL cm-2 versus 0.05 ± 0.006 µL cm-2 ), larval mortality by 27.7% (60.7 ± 4.1% versus 84.0 ± 2.4%), and ground level Bti concentrations by 32.03% (1144 ± 462.6 versus 1683 ± 447.8 spores mL-1 ) relative to open saltmarsh. Persistence of product post-application was found to be low (80.6% loss at 6 h) resulting in negligible additional losses to tidal inundation 24 h post-application. UAS surveys accurately identified areas of high mangrove cover using both standard and multispectral imagery, although derived index values for this vegetation class were only moderately correlated with ground measurements (R2 = 0.17-0.38) at their most informative scales. CONCLUSION: These findings highlight the complex operational challenges that affect coastal mosquito control in heterogeneous environments. The problem is exacerbated by continued mangrove transgression into saltmarsh habitat in the region. Emerging UAS technology can help operators optimize treatments by accurately identifying and mapping challenging canopy cover using both standard and multispectral imaging. © 2020 Society of Chemical Industry.

Further Evidence that Development and Buffer Zones Do Little To Reduce Mosquito Nuisance from Neighboring Habitat.

Little is known regarding the comparative source-sink relationships between primary mosquito breeding sites (source) and neighboring (sink) environments in heterogeneous landscapes. An exploration of those relationships may provide unique insights into the utility of open-space buffer zone mitigation strategies currently being considered by urban planners to reduce contact between mosquitoes and humans. We investigated the source-sink relationships between a highly productive mosquito habitat and adjacent residential (developed) and rural (undeveloped) coastal environments. Our results suggest that source-sink relationships are unaffected by environment. This conclusion is supported by the high level of synchronicity in daily saltmarsh mosquito abundance observed among all surveyed environments (ß = 0.67-0.79, P < 0.001). This synchronicity occurred despite the uniqueness of each surveyed environment and the considerable distances of open water and land (2.2-2.6 km) between them. Trap catches, which we interpret as expected mosquito biting nuisance, were high in both residential and rural coastal landscapes (309.4 ± 52.84 and 405.3 ± 62.41 mosquitoes/day, respectively). These observations suggest that existing and planned open-space buffer zones will do little to reduce the biting burden caused by highly vagile saltmarsh mosquitoes. This strengthens the need for empirically informed planning guidelines that alert urban planners to the real risks of human residential encroachment on land that is close to highly vagile mosquito habitat.

Mosquito Age Grading and Vector-Control Programmes.

An ability to characterize the age of mosquito populations could provide cost-effective and compelling entomological evidence for the potential epidemiological impacts of vector control. The average age of a mosquito population is the most important determinant of vectorial capacity and the likelihood of disease transmission. Yet, despite decades of research, defining the age of a wild-caught mosquito remains a challenging, impractical, and unreliable process. Emerging chemometric and existing transcriptional approaches may overcome many of the limitations of current morphological techniques, but their utility in terms of field-based monitoring programmes remains largely untested. Herein, we review the potential advantages and disadvantages of new and existing age-grading tools in an operational context.

A Novel Methodology For Recording Wing Beat Frequencies of Untethered Male and Female Aedes aegypti.

Aedes aegypti is a vector of many significant arboviruses worldwide, including dengue, Zika, chikungunya, and yellow fever viruses. With vector control methodology pivoting toward rearing and releasing large numbers of insects for either population suppression or virus-blocking, economical remote (sentinel) surveillance methods for release tracking become increasingly necessary. Recent steps in this direction include advances in optical sensors that identify and classify insects based on their wing beat frequency (WBF). As these traps are being developed, there is a strong need to better understand the environmental and biological factors influencing mosquito WBFs. Here, we developed new untethered-subject methodology to detect changes in WBFs of male and female Ae. aegypti. This new methodology involves directing an ultrasonic transducer at a free-flying subject and measuring the Doppler shift of the reflected ultrasonic continuous wave signal. This system's utility was assessed by determining its ability to confirm previous reports on the effect of temperature, body size, and age on the WBFs generated from acoustic or optical-based experiments. The presented ultrasonic method successfully detected expected trends for each factor for both male and female Ae. aegypti without the need for subject manipulation and potential impediment of natural flight dynamics due to tethering. As a result, this ultrasonic methodology provides a new method for understanding the environmental and physiological determinants of male and female WBFs that can inform the design of remote mosquito surveillance systems.

Neighbors help neighbors control urban mosquitoes.

The worldwide spread of invasive Aedes mosquitoes and arboviral disease, have renewed the pressure for effective and sustainable urban mosquito control. We report on the success of a model we are confident will usher in a new era of urban mosquito control. The key innovation is the mobilization of neighbors guided by scientific advisors, an approach we termed Citizen Action through Science (Citizen AcTS). This approach was tested in a NE US town of approximately 1,000 residential yards infested with the invasive Asian tiger mosquito, Aedes albopictus, a major nuisance arboviral vector. We report a highly significant reduction in biting pressure that was maintained over time, and establish the thresholds needed for success. The Citizen AcTS model rejects the top-down approach consistently associated with intervention failures. Instead, it works through respectful exchanges among scientists and residents that lead to trust and individual 'buy-in' and transferring program ownership to the community.

A low-cost, battery-powered acoustic trap for surveilling male Aedes aegypti during rear-and-release operations.

The Aedes aegypti mosquito is a primary vector of several serious arboviruses throughout the world and is therefore of great concern to many public health organizations. With vector control methodology pivoting towards rearing and releasing large numbers of genetically modified, sterilized, or Wolbachia-infected male mosquitoes to control vector populations, economical surveillance methods for release tracking becomes increasingly necessary. Previous work has identified that male Ae. aegypti are attracted to female wingbeat frequencies and can be captured through artificial playback of these frequencies, but the tested systems are cost-prohibitive for wide-scale monitoring. Thus, we have developed a simple, low-cost, battery-powered, microcontroller-based sound lure which mimics the wingbeat frequency of female Ae. aegypti, thereby attracting males. We then tested the efficacy of this lure in combination with a passive (non-powered) gravid Aedes trap (GAT) against the current gold-standard, the Biogents Sentinel (BGS) trap, which requires main power (household power) and costs several times what the GAT does. Capture rates of male Ae. aegypti in sound-baited GATs (Sound-GATs) in these field tests were comparable to that of the BGS with no inhibitory effects of sound playback on female capture. We conclude that the Sound-GAT is an effective replacement of the costly BGS for surveillance of male Ae. aegypti mosquitoes, particularly in the developing countries where funding is limited, and has the potential to be adapted to target males of other medically important species.