Efficiency of the CO2 -baited omni-directional Fay-Prince trap under semi-field conditions and characterizing response behaviours for the yellow fever mosquito, Aedes aegypti.

Aedes aegypti (L.) (Diptera: Culicidae) is a vector of several serious disease-causing viruses including Dengue, Zika, chikungunya and yellow fever. Effective and efficient trapping methods are essential for meaningful mosquito population and disease-presence surveillance and ultimately, vector control. The Fay-Prince trap (FPT) was developed in the late 1960s as a daytime visual trap for male Ae. aegypti. Since then, its use has been expanded into the trapping of female Ae. aegypti, Aedes albopictus Skuse, other Ae. spp., and Culex spp. The efficiency of the FPT alone and with CO2 was tested under semi-field conditions and the behaviour of responding female Ae. aegypti was characterized. The mean capture efficiency of the FPT with CO2 per 30 min in the greenhouse was 3.07% and the capture rate from the total number of mosquitoes in our semi-field setup was slightly higher at 4.45%. Understanding the behaviours that mosquitoes exhibit during their encounter with particularly a visual trap may recommend trap improvements and contributes to our understanding of host-seeking behaviour and how it might be exploited.

Is increased screening and early antiretroviral treatment for HIV-1 worth the investment? An analysis of the public health and economic impact of improvement in the UK.

OBJECTIVES: Early treatment of HIV-1 infection at all CD4 levels has demonstrated clinical and public health benefits. This analysis examined the costs, health outcomes, and cost-effectiveness of increased HIV-1 screening and early treatment initiation in the UK. METHODS: A Markov model followed theoretical cohorts of men who have sex with men (MSM), heterosexuals, and people who inject drugs (PWID) with initially undiagnosed HIV-1 infection over their remaining lifetimes. The analysis examined increased HIV-1 screening (resulting in 10-50% improvements in diagnosis rates) versus current screening in sexual health services (SHS) and other settings, with all individuals initiating treatment within 3 months of diagnosis. Health status was modelled by viral load and CD4 cell count as individuals progressed to diagnosis and treatment. Individuals accrued quality-adjusted life-years (QALYs), incurred costs for screening and HIV-related clinical management, and were at risk of transmitting HIV-1 infection to their partners. Input parameter data were taken primarily from UK-specific published sources. All outcomes were discounted at 3.5% annually. RESULTS: The model estimated that increased screening and early treatment resulted in fewer onward HIV transmissions, more QALYs, and higher total costs. For SHS, incremental cost-effectiveness ratios (ICERs) for heterosexuals (~£22 000/QALY gained) were within typical UK willingness-to-pay thresholds and were well below these thresholds for MSM (~£9500/QALY gained) and PWID (~£6500/QALY gained). Sensitivity analysis showed that model results were robust. CONCLUSIONS: Increased HIV-1 screening and early treatment initiation may be a cost-effective strategy to reduce HIV transmission and improve health for MSM, heterosexuals, and PWID in the UK.

Dynamic transmission modelling to address infant pneumococcal conjugate vaccine schedule modifications in the UK.

The 13-valent pneumococcal conjugate vaccine (PCV) has been part of routine immunisation in a 2 + 1 schedule (two primary infant doses and one booster during the second year of life) in the UK since 2010. Recently, the UK's Joint Committee on Vaccination and Immunisation recommended changing to a 1 + 1 schedule while conceding that this will increase disease burden; however, uncertainty remains on how much pneumococcal burden - including invasive pneumococcal disease (IPD) and non-invasive disease - will increase. We built a dynamic transmission model to investigate this question. The model predicted that a 1 + 1 schedule would incur 8777-27 807 additional cases of disease and 241-743 more deaths over 5 years. Serotype 19A caused 55-71% of incremental IPD cases. Scenario analyses showed that booster dose adherence, effectiveness against carriage and waning in a 1 + 1 schedule had the most influence on resurgence of disease. Based on the model assumptions, switching to a 1 + 1 schedule will substantially increase disease burden. The results likely are conservative since they are based on relatively low vaccine-type pneumococcal transmission, a paradigm that has been called into question by data demonstrating an increase of IPD due to several vaccine serotypes during the last surveillance year available.

Cost-effectiveness analysis of tenofovir/emtricitabine and abacavir/lamivudine in combination with efavirenz or atazanavir/ritonavir for treatment-naïve adults with HIV-1 infection in the UK, based on the AIDS Clinical Trials Group 5202 clinical trial.

OBJECTIVES: The aim of the study was to assess the cost-effectiveness of the four regimens studied in the AIDS Clinical Trials Group (ACTG) 5202 clinical trial, tenofovir/emtricitabine (TDF/FTC) or abacavir/lamivudine (ABC/3TC) in combination with efavirenz (EFV) or atazanavir/ritonavir (ATV/r), for treatment-naïve adults with HIV-1 infection in the UK. METHODS: A Markov model with six health states based on CD4 cell count ranges was developed to predict long-term costs and health outcomes for individuals on first-line therapy. Head-to-head efficacy data comparing TDF/FTC + EFV, TDF/FTC + ATV/r, ABC/3TC + EFV, and ABC/3TC + ATV/r were obtained from ACTG 5202 for up to 192 weeks. Antiretroviral drug costs were based on current list prices. Other medical costs (2013 UK pounds sterling), utility values, and mortality rates were obtained from published sources. Base-case, sensitivity, and subgroup analyses (by baseline viral load) were conducted. RESULTS: Individuals using TDF/FTC-based regimens were predicted to remain on first-line therapy longer and accrue more quality-adjusted life-years (QALYs) than individuals using ABC/3TC-based regimens. At a willingness-to-pay threshold of £30 000 per QALY gained, TDF/FTC-based regimens were predicted to be cost-effective compared with ABC/3TC-based regimens, with incremental cost-effectiveness ratios of £23 355 for TDF/FTC + EFV vs. ABC/3TC + EFV and £23 785 for TDF/FTC + ATV/r vs. ABC/3TC + ATV/r. Results were generally robust in subgroup, sensitivity, and scenario analyses. CONCLUSIONS: In an analysis of the regimens studied in ACTG 5202 for treatment-naïve adults with HIV-1 infection in the UK, TDF/FTC-based regimens yielded more favourable health outcomes and were generally predicted to be cost-effective compared with ABC/3TC-based regimens. These results confirm that TDF/FTC-based regimens are not only clinically effective but also cost-effective.

Verifying the efficiency of the Biogents Sentinel trap in the field and investigating microclimatic influences on responding Aedes aegypti behavior.

Successful surveillance and control of mosquito arbovirus vectors requires effective and sensitive trapping methods for adult insects. The Biogents Sentinel (BGS) trap is widely used for mosquito trapping but has low capture efficiency for both female and male Aedes aegypti under semi-field conditions. Efficiency refers to the proportion of mosquitoes that are trapped of those encountering the trap. We verified the efficiency of the BGS under field conditions in suburban Riverside, California, U.S.A., following our previous work determining the efficiency under semi-field conditions in Cairns, Northern Australia. The efficiency of the BGS with CO2 and a human skin odor mimic (BG-Lure) for both Ae. aegypti sexes in the field was 9%. This closely aligns with the results of our previous study, the efficiency for females being 5% and males being 9%. In the present study microclimatic conditions were monitored and capture occurred during periods of significantly lower mean temperature. There were no discernible changes in wind directionality or strength in the 60 s leading up to mosquito capture by the BGS. Our results support our previous findings that capture efficiency of the BGS for Ae. aegypti is low.

Long-Range But Not Short-Range Attraction of Male Aedes aegypti (Diptera: Culicidae) Mosquitoes to Humans.

Female Aedes aegypti (Linnaeus) mosquitoes integrate multiple sensory cues to locate human hosts for blood meals. Although male Ae. aegypti swarm around and land on humans in nature to mate, direct evidence of attraction to humans is limited. Male mosquito attraction to human host cues is often undetectable in confined laboratory assays, leading to a misconception that male mosquitoes are not attracted to humans. We used semifield experiments to demonstrate robust attraction of male Ae. aegypti to humans. Human-baited traps captured up to 25% of released males within 15 min, whereas control traps without humans as bait failed to capture males. Rapid attraction to humans was further demonstrated through videography. Males swarmed around and landed on human subjects, with no activity recorded in paired unbaited controls. Finally, we confirm the lack of discernible male attraction to humans in small laboratory cages. Our experiments demonstrate that both male and female Ae. aegypti show attraction to humans, but with clear sex-specific behavioral differences at short-range. Male mosquito attraction to humans is likely to be important for mating success in wild populations and its basis should be further explored. Our results highlight the importance of arena size and assay design for mosquito behavioral research. A better understanding of host cues that attract males could help us to improve mosquito surveillance and control.

Attraction Versus Capture II: Efficiency of the BG-Sentinel Trap Under Semifield Conditions and Characterizing Response Behaviors of Male Aedes aegypti (Diptera: Culicidae).

Aedes aegypti (L.) is an important vector of viruses causing dengue, Zika, chikungunya, and yellow fever and as such presents a serious threat to public health in tropical regions. Control programs involving 'rear and release' of modified male Ae. aegypti are underway and require effective trapping methods for surveillance of both the released insects and the impacted wild mosquito population. The BG-Sentinel trap (BGS) is widely used in Ae. aegypti surveillance but its level of efficiency, that is, what proportion of the mosquitoes encountering the trap are captured, is unknown. This is especially true for male mosquitoes, the behavior of which is incompletely understood. We tested the efficiency of two versions of the BGS for capturing male Ae. aegypti under semifield conditions with and without CO2 and a human skin odor mimic lure and with these baits combined. A navy-blue BGS trap emitting CO2 and a human skin odor mimic captured 18% of the released male Ae. aegypti, with a capture efficiency of 9 % (of the total encounters with the trap). Male Ae. aegypti had multiple encounters with the BGS that did not result in capture; they crossed over the trap entrance without being captured or landed on the sides of the trap. Swarming behavior around the BGS was also recorded, even when only a visual cue was present. Understanding male Ae. aegypti behaviors during an encounter with the BGS can inform improvement of trap design and therefore capture efficiency for surveillance in control programs.

Attraction Versus Capture: Efficiency of BG-Sentinel Trap Under Semi-Field Conditions and Characterizing Response Behaviors for Female Aedes aegypti (Diptera: Culicidae).

Aedes aegypti (L.) is an important vector of viruses causing dengue, Zika, chikungunya, and yellow fever and as such is a threat to public health worldwide. Effective trapping methods are essential for surveillance of both the mosquito species and disease presence. The BG-Sentinel (BGS) is a widely used to trap Ae. aegypti but little is known of its efficiency, i.e., what proportion of the mosquitoes encountering the trap are captured. The first version of the BGS trap was predominantly white, and the current version is mostly navy blue. While this trap is often deployed without any olfactory lure, it can also be deployed with CO2 and/or a human skin odor mimic lure to increase capture rates. We tested the efficiency of capturing Ae. aegypti under semi-field conditions for the original white version without lures as well the blue version with and without various lure combinations. None of the configurations tested here captured 100% of the mosquitoes that encountered the trap. A navy-blue trap emitting CO2 and a skin odor mimic produced the highest capture (14% of the total insects in the semi-field cage), but its capture efficiency was just 5% (of mosquitoes encountering the trap). Mosquitoes often had multiple encounters with a trap that did not result in capture; they crossed over the trap entrance without being captured or landed on the sides of the trap. Understanding these behaviors and the factors that induce them has the potential to suggest improvement in trap design and therefore capture efficiency.

The structure of the causal attribution belief network of patients with obesity.

OBJECTIVES: Causal attributions form a significant part of how people understand and represent illness. The present study explored the structure of causal attributions in obesity using network analysis and examined the specific properties of this network in terms of extent, patterning, and direction. DESIGN: Cross-sectional study. METHODS: Seventy-two obese individuals (22 male, 50 female) completed a questionnaire, which asked them to rate the strength of all causal relationships between nine possible causes of obesity. Inductive eliminative analysis (IEA) was used to produce the networks and multidimensional scaling (MDS) determined the spatial structure of the network. RESULTS: A high percentage (70.4%) of participants endorsed the resultant network. Analysis revealed a two-dimensional solution, with the MDS statistics of low level of stress (.05) and a dispersion accounted for (DAF) of .95 indicating a good fit between the data and the solution. The results indicated traumatic events, family problems, and addictive personality were perceived as distal causes of over-eating and comfort eating, while more passive behaviours, less physical activity, over-eating, and comfort eating were perceived as proximal causes of obesity. Family history did not contribute to the network. CONCLUSIONS: Obese individuals appeared to hold a highly consensual and complex representation of their illness. From a multidisciplinary treatment perspective, this understanding would seem valuable in relation to achieving behaviour change.

Small Hive Beetle (Coleoptera: Nitidulidae) and the Yeast, Kodamaea ohmeri: A Facultative Relationship Under Laboratory Conditions.

The small hive beetle, Aethina tumida Murray, is a pest of honeybees, Apis mellifera L. (Hymenoptera: Apidae). We investigated the significance of its association with the yeast, Kodamaea ohmeri (Etchells & Bell) (Ascomycota: Saccharomycotina), in laboratory experiments. The mean (± SEM) viability of A. tumida eggs was 84 (± 3)%; the viability was not affected if eggs were separated from clutches or if mucilage containing K. ohmeri was removed from the egg surface. Life tables of conventional (= K. ohmeri contaminated) A. tumida and K. ohmeri-free A. tumida revealed no differences in stage-specific mortality between the treatments; in both cases, the highest mortality occurred in the first larval instar. There was no significant difference in the initial egg production of conventionally reared and K. ohmeri-free A. tumida under laboratory conditions. The volatile profiles of pollen dough (Bee Build) fed on by conventional and K. ohmeri-free A. tumida larvae were qualitatively and quantitatively different; the volatiles produced by pollen dough fed on by conventional A. tumida were more attractive to adult beetles. There was a clear difference between growth of K. ohmeri on pollen dough substrate in the presence and absence of A. tumida. Results suggest that this association is facultative for A. tumida under laboratory conditions but has benefit for the yeast associate, K. ohmeri. A clearer understanding of the nature of this fungus-insect association is essential for the development of management strategies for this pest, especially in the development of fermentate-based attractants in trapping systems.

Associations Between the Small Hive Beetle and the Yeast Kodamaea ohmeri Throughout the Host Life Cycle.

The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is a pest of colonies of social bees, including the honeybee Apis mellifera L. (Hymenoptera: Apidae). We investigated A. tumida oviposition behavior and development and found that it laid eggs in clutches that ranged in size (3-75 eggs per clutch) and that when fed on hive products in laboratory culture (27°C; RH 65%; 12:12 (L:D) h) it completed three larval instars before pupation. The yeast Kodamaea ohmeri (Etchells & Bell) Y. Yamada, T. Suzuki, M. Matsuda & K. Mikata (Ascomycota: Saccharomycotina) is associated with A. tumida, but the exact nature of this relationship is unknown. We examined the association in host eggs, larvae, pupae, and adults to establish its extent and potential specificity and determined the likely mechanism of vertical transmission. K. ohmeri was detected in egg mucilage and on host cuticle and from internal preparations of A. tumida at every stage of development. Based on colony forming unit (CFU) counts, the K. ohmeri densities varied significantly between developmental stages; the highest internal density was recorded in third instar larvae. Presence of K. ohmeri within adult A. tumida was not affected by contamination of the cuticle by the yeast during the larval and pupal stages nor by the mated status of the adult. This deepened understanding of A. tumida ovipositional behavior and larval development along with a better understanding of the relationship between K. ohmeri and its host is important for the development of management strategies for this important pest.