scholarly journals Bed Bug (Hemiptera: Cimicidae) Attraction to Human Odors: Validation of a Two-Choice Olfactometer

2018 ◽  
Vol 56 (2) ◽  
pp. 362-367 ◽  
Author(s):  
Zachary C DeVries ◽  
Ahmed M Saveer ◽  
Russell Mick ◽  
Coby Schal
Keyword(s):  
Host Location ◽  
Response Rate ◽  
Response Rates ◽  
Adult Males ◽  
Bed Bugs ◽  
Host Attraction ◽  
Bed Bug ◽  
Survival And Reproduction ◽  
Different Populations ◽  
Human Participants

Abstract Bed bugs (Cimex lectularius L.) (Hemiptera: Cimicidae) are obligate hematophagous ectoparasites, and, therefore, must locate suitable hosts to ensure survival and reproduction. Their largely nocturnal activity suggests that chemosensory and thermosensory cues would play critical roles in host location. Yet, the importance of olfaction in host attraction of bed bugs remains unclear. We developed and validated a Y-tube, two-choice olfactometer and tested its suitability for investigating attraction to human odors (from skin swabs). Olfactometer orientation significantly affected the percentage of bed bugs that were activated by human odors, with significantly more bed bugs responding when the olfactometer was oriented vertically (bug introduced at bottom of the olfactometer) compared with all other orientations. Starved (7–10 d) adult males, mated females, and nymphs responded (47–77% moved up the olfactometer and made a choice) when human odors were present in the olfactometer, while starved, unmated females did not respond. Skin swabs from all five human participants elicited high response rates (65–82%), and bed bugs from four different populations responded to skin swabs (40–82% response rate). However, in all assays including those resulting in relatively low response rates, bed bugs exhibited >90% preference for human odors over blank controls. These results provide strong evidence that bed bugs can respond and orient towards human odors, independently of all other host cues. Furthermore, the validated olfactometer should enable rapid and efficient evaluations of bed bug behavioral responses to semiochemicals.

scholarly journals The Role of Antennae in Heat Detection and Feeding Behavior in the Bed Bug (Hemiptera: Cimicidae)

2020 ◽  
Vol 113 (6) ◽  
pp. 2858-2863
Author(s):  
Sudip Gaire ◽  
Coby Schal ◽  
Russell Mick ◽  
Zachary DeVries
Keyword(s):  
Heat Source ◽  
Antennal Segment ◽  
Well Being ◽  
Radiant Heat ◽  
Bed Bugs ◽  
Host Attraction ◽  
Bed Bug ◽  
The Common ◽  
Health And Well Being

Abstract The common bed bug (Cimex lectularius L.) is an obligate hematophagous ectoparasite that has significant impacts on human health and well-being. All life stages of bed bugs (except eggs) feed solely on blood, which is required to molt and reproduce. Bed bugs use multiple cues to locate their hosts, including heat, CO2, and body odors. Of these cues, detection of heat appears limited to a short distance of <3 cm. However, it remains unclear if bed bugs can detect radiant heat, what structure(s) are responsible for heat detection, and if heat detection via the antennae is required for feeding. In this study, bed bug response to radiant heat was evaluated using the two-choice T-maze assay with the heat source either in contact with the surface (i.e., conduction) or not in contact (i.e., radiation) in nonantennectomized bed bugs. Further, we systematically ablated the bed bug’s antennal segments (distal tip, first segment, and all four segments) and assessed their responses to heat and feeding in a unique two-choice T-maze assay and individual feeding assays, respectively. Our two-choice assays with contact to or no contact with the surface indicated that bed bugs cannot detect radiant heat. Later, we found that the distal tip of the terminal antennal segment is responsible for orientation toward a heat source. However, >50% of the bed bugs fed even when the entire antenna was removed, suggesting redundancy in sensory cues that drive feeding. These results will be used to better understand the role heat plays in bed bug host attraction and design of traps.

Comparing face-to-face to web data collection: unit response and costs in a national health survey (Preprint)

2020 ◽  
Author(s):  
Elise Braekman ◽  
Stefaan Demarest ◽  
Rana Charafeddine ◽  
Sabine Drieskens ◽  
Finaba Berete ◽  
...  
Keyword(s):  
Data Collection ◽  
Response Rate ◽  
Response Rates ◽  
Demographic Characteristics ◽  
Unit Response ◽  
Cost Advantage ◽  
Web Data ◽  
Demographic Groups ◽  
Considerable Cost ◽  
The Difference

BACKGROUND Potential is seen in web data collection for population health surveys due to a combination of its cost-effectiveness, implementation ease and the increased internet penetration. Nonetheless, web modes may lead to lower and more selective unit response rates than traditional modes and hence may increase bias in the measured indicators. OBJECTIVE This research assesses the unit response and costs of a web versus F2F study. METHODS Alongside the F2F Belgian Health Interview Survey of 2018 (BHIS2018; n gross sample used: 7,698), a web survey (BHISWEB; n gross sample=6,183) is organized. Socio-demographic data on invited individuals is obtained from the national register and census linkages. Unit response rates considering the different sampling probabilities of both surveys are calculated. Logistic regression analyses examine the association between mode system (web vs. F2F) and socio-demographic characteristics on unit non-response. The costs per completed web questionnaire are compared with these for a completed F2F questionnaire. RESULTS The unit response rate is lower in BHISWEB (18.0%) versus BHIS2018 (43.1%). A lower web response is found among all socio-demographic groups, however, the difference is higher among people older than 65, low educated people, people with a non-Belgian nationality, people living alone and these living in Brussels Capital. Not the same socio-demographic characteristics are associated with non-response in both studies. Having another European (OR (95% CI): 1.60 (1.20-2.13)) or a non-European nationality (OR (95% CI): 2.57 (1.79-3.70)) (compared to having the Belgian nationality) and living in the Brussels Capital (95% CI): 1.72 (1.41-2.10)) or Walloon (OR (95% CI): 1.47 (1.15 - 1.87) region (compared to living in the Flemish region) is only in BHISWEB associated with a higher non-response. In BHIS2018 younger people (OR (95% CI): 1.31 (1.11-1.54)) are more likely to be non-respondent than older people, this was not found BHISWEB. In both studies, lower educated people have a higher change to be non-respondent, but this effect is more pronounced in BHISWEB (OR low vs. high education level (95% CI): Web 2.71 (2.21-3.39)); F2F 1.70 (1.48-1.95)). The BHISWEB study has a considerable cost advantage; the total cost per completed questionnaire is almost three times lower (€41) compared to the F2F data collection (€111). CONCLUSIONS The F2F unit response rate is generally higher, yet for certain groups the difference between web versus F2F is more limited. A considerable cost advantage of web collection is found. It is therefore worthwhile to experiment with adaptive mixed-mode designs to optimize financial resources without increasing selection bias; e.g. only inviting socio-demographic groups more eager to participate online for web surveys while remaining to focus on increasing the F2F response rates for other groups. CLINICALTRIAL Studies approved by the Ethics Committee of the University hospital of Ghent

scholarly journals Widespread Mutations in Voltage-Gated Sodium Channel Gene of Cimex lectularius (Hemiptera: Cimicidae) Populations in Paris

2021 ◽  
Vol 18 (2) ◽  
pp. 407
Author(s):  
Mohammad Akhoundi ◽  
Dahlia Chebbah ◽  
Denis Sereno ◽  
Anthony Marteau ◽  
Julie Jan ◽  
...  
Keyword(s):  
Single Point ◽  
Cimex Lectularius ◽  
Single Point Mutation ◽  
Homozygous Mutation ◽  
Knockdown Resistance ◽  
Bed Bugs ◽  
Bed Bug ◽  
Channel Gene ◽  
Blood Sucking ◽  
The Status

Bed bugs, Cimex lectularius and C. hemipterus, are common blood-sucking ectoparasites of humans with a large geographical distribution, worldwide. In France, little is known about the status of bed bugs’ infestation and their resistance to insecticides, particularly, pyrethroids. Here, we aimed to find mutations in the kdr gene, known to be involved in resistance to insecticides. We gathered bed bugs from various infested locations, including 17 private houses, 12 HLM building complex, 29 apartments, 2 EHPAD, and 2 immigrants’ residences. A total of 1211 bed bugs were collected and morphologically identified as C. lectularius. Two fragments of the kdr gene, encompassing codons V419L and L925I, were successfully amplified for 156 specimens. We recorded sense mutation in the first amplified fragment (kdr1) in 89 out of 156 (57%) samples, in which in 61 out of 89 (68.5%) sequences, a change of valine (V) into leucine (L) V419L was observed. Within the second fragment (kdr2), a homozygous mutation was recorded in 73 out of 156 (46.7%) specimens at the codon 925. At this position, 43 out of 73 (58.9%) specimens had a sense mutation leading to the replacement of leucine (L) by isoleucine (I). Among 162 mutant sequences analyzed (89 for the kdr1 fragment and 73 for the kdr2 one), we detected single point mutation in 26.6%, while 73.4% presented the mutation in both kdr1 and kdr2 fragments. All modifications recorded in bed bug populations of Paris are described to be involved in the knockdown resistance (kdr) against pyrethroids.

scholarly journals CGRP-antibodies, topiramate and botulinum toxin type A in episodic and chronic migraine: A systematic review and meta-analysis

Cephalalgia ◽  
2021 ◽  
pp. 033310242110181
Author(s):  
Florian Frank ◽  
Hanno Ulmer ◽  
Victoria Sidoroff ◽  
Gregor Broessner
Keyword(s):  
Systematic Review ◽  
Monoclonal Antibodies ◽  
Botulinum Toxin ◽  
Response Rate ◽  
Meta Analysis ◽  
Botulinum Toxin Type A ◽  
Type A ◽  
Response Rates ◽  
Botulinum Toxin Type ◽  
Odds Ratios

Background The approval of monoclonal antibodies for prevention of migraine has revolutionized treatment for patients. Oral preventatives are still considered first line treatments as head-to-head trials comparing them with antibodies are lacking. Methods The main purpose of this study was to provide a comparative overview of the efficacy of three commonly prescribed migraine preventative medication classes. For this systematic review and meta-analysis, we searched the databases CENTRAL, EMBASE, and MEDLINE until 20 March 2020. We included RCTs reporting the 50% response rates for topiramate, Botulinum Toxin Type A and monoclonal antibodies against CGRP(r). Studies were excluded if response rates were not reported, treatment allocation was unclear, or if study quality was insufficient. Primary outcome measure were the 50% response rates. The pooled odds ratios with 95% confidence intervals were calculated with the random effects model. The study was registered at PROSPERO (CRD42020222880). Findings We identified 6552 reports. Thirty-two were eligible for our review. Studies assessing monoclonal antibodies included 13,302 patients and yielded pooled odds ratios for the 50% response rate of 2.30 (CI: 2.11–2.50). Topiramate had an overall effect estimate of 2.70 (CI: 1.97–3.69) with 1989 included patients and Botulinum Toxin Type A achieved 1.28 (CI: 0.98–1. 67) with 2472 patients included. Interpretation Topiramate, botulinum toxin type A and monoclonal antibodies showed higher odds ratios in achieving a 50% response rate compared to placebo. Topiramate numerically demonstrated the greatest effect size but also the highest drop-out rate.

The Behavioral Response to Heat in the Common Bed Bug,Cimex lectularius (Hemiptera: Cimicidae)

2021 ◽  
Author(s):  
Raymond Berry
Keyword(s):  
Petri Dish ◽  
Cimex Lectularius ◽  
Bed Bugs ◽  
Bed Bug ◽  
Host Interaction ◽  
Video Images ◽  
Spherical Ball ◽  
The Common ◽  
Vertebrate Hosts

AbstractThe bed bug, Cimex lectularius L., is a common ectoparasite found to live among its vertebrate hosts. Antennal segments in bugs are critical for sensing multiple cues in the environment for survival. To determine whether the thermo receptors of bed bugs are located on their antennae; innovative bioassays were created to observe the choice between heated and unheated stimuli and to characterize the response of bugs to a heat source. Additionally, the effect of complete antenectomized segments on heat detection were evaluated. Heat, carbon dioxide, and moisture are cues that are found to activate bed bug behavior; a temperature at 38°C was used to assess the direction/degree at which the insect reacts to the change in distance from said stimulus. Using a lightweight spherical ball suspended by air through a vacuum tube, bed bugs and other insects are able to move in 360° while on a stationary point. Noldus EthoVision XT was used to capture video images and to track the bed bugs during 5-min bioassays. A bioassay was created using four Petri dish arenas to observe bed bug attraction to heat based on antennae segments at 40°C. The purpose of this study was to evaluate the effects of heat on complete antenectomized segments of the antennae. The results in this experiment suggest that bed bugs detect and are attracted to heat modulated by nutritional status. Learning the involvement of antennae segments in heat detection will help identify the location and role of thermoreceptors for bed bug host interaction.

scholarly journals Evaluation of a Non-Chemical Compared to a Non-Chemical Plus Silica Gel Approach to Bed Bug Management

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 443
Author(s):  
Salehe Abbar ◽  
Changlu Wang ◽  
Richard Cooper
Keyword(s):  
Silica Gel ◽  
Chemical Treatment ◽  
Bed Bugs ◽  
Chemical Methods ◽  
Bed Bug ◽  
Treatment Groups ◽  
Dust Treatment ◽  
Residual Control ◽  
Insecticide Sprays ◽  
Bug Management

Bed bug resistance to commonly used pesticide sprays has led to exploring new pesticides and other strategies for bed bug management. Non-chemical methods are effective in bed bug management; however, they do not provide residual protection. Compared to insecticide sprays, dust formulations are considered to provide longer residual control. We evaluated two bed bug management programs in apartment buildings. A building-wide inspection was initially conducted to identify bed bug infested apartments. Selected apartments were divided into two treatment groups: non-chemical plus silica gel dust treatment (10 apartments) and non-chemical treatment (11 apartments). After initial treatment, apartments were re-visited monthly for up to 6 months. During each visit, the total bed bug count per apartment was obtained by examining interceptor traps placed in the apartments and conducting a visual inspection. Mean bed bug count was reduced by 99% and 89% in non-chemical plus silica gel dust and non-chemical treatment, respectively. Non-chemical plus silica gel dust treatment caused significantly higher bed bug count reduction than the non-chemical treatment at 6 months. Bed bugs were eradicated from 40% and 36% of apartments treated with non-chemical plus silica gel dust treatment and non-chemical treatment, respectively.

Provinciale responsverschillen in het Vlaamse Bevolkingsonderzoek Dikkedarmkanker: inzichten uit gemeentelijke socio-demografische en gezondheidsgerelateerde kenmerken

2021 ◽  
Author(s):  
T.N. TRAN ◽  
G. VAN HAL ◽  
M. PEETERS ◽  
S. JIDKOVA ◽  
S. HOECK
Keyword(s):  
Colorectal Cancer ◽  
Response Rate ◽  
Response Rates ◽  
Target Population ◽  
Wilcoxon Test ◽  
Future Research ◽  
Screening Methods ◽  
Average Income ◽  
Medical File ◽  
Crc Screening

Municipal characteristics associated with response rate to organised colorectal cancer screening in Flanders Introduction In Flanders (Belgium), the response rate to organised colorectal cancer (CRC) screening is still suboptimal (~ 50%). We studied the characteristics of municipalities in the Flemish provinces with the highest and lowest response rates to explore factors that might be associated with the response rate to organised CRC screening. Methods The response rates of municipalities in 5 Flemish provinces and the characteristics of municipalities in the provinces with the highest and lowest response rates were compared to the average measures of Flanders (data 2017) using an unpaired two-sample Wilcoxon test. Results The municipal response rates in Limburg and Antwerp were significantly higher, and those in West Flanders and Flemish Brabant significantly lower compared to Flanders. Further analyses of Limburg (highest response rate) and Flemish Brabant (lowest response rate) suggested that municipalities with higher response rates had more men and people aged 60-64 in the target population, more jobseekers and more people who contacted GPs/specialists frequently, but fewer people aged 70-74 in the target population and with a lower average income compared to Flanders. In contrast, municipalities with lower response rates had fewer men in the target population, fewer people having a partner, fewer jobseekers and fewer people having a global medical file, but more people with a non-Dutch or non-Belgian nationality and a higher average income (p-values < 0.01). Conclusion This exploratory study identifies certain demographic, socioeconomic and health‑related municipal characteristics that may be related to the response rate to CRC screening in Flanders. These findings can guide future research and investigations with the aim to improve the response rate to CRC screening.

scholarly journals Portuguese Primary Care physicians response rate in surveys: A systematic review

2018 ◽  
Vol 64 (3) ◽  
pp. 272-280 ◽  
Author(s):  
Nuno Basílio ◽  
Sara Cardoso ◽  
José Mendes Nunes ◽  
Liliana Laranjo ◽  
Maria da Luz Antunes ◽  
...  
Keyword(s):  
Primary Care ◽  
Primary Care Physicians ◽  
Response Rate ◽  
Internal Validity ◽  
Response Rates ◽  
Monetary Incentives ◽  
Average Response ◽  
Average Response Rate ◽  
Effective Strategies ◽  
E Mail

Summary Introduction: Surveys are a useful tool in primary care. However, low response rates can introduce selection bias, impairing both external and internal validity. The aim of this study was to assess the average response rate in surveys with Portuguese general practitioners (GPs). Method: We searched the Medline, Web of Science, Scopus, Embase, PsychInfo, SciELO, IndexRMP, RCAAP, Revista Portuguesa de Medicina Geral e Familiar, Acta Médica Portuguesa and the proceedings of conferences of general practice from incepton to December 2016. We included all postal, e-mail, telephone and personal surveys to primary care physicians without language restrictions. We did not assess risk of bias of included studies, since the main outcome was survey response rate. We performed planned subgroup analyses of the use of monetary incentives, the use of non-monetary incentives, survey delivery modes and prior contact with participants. Results: A total of 1,094 papers were identified and 37 studies were included in this review. The response rate in surveys done to Portuguese GPs was 56% (95CI 47-64%). There was substantial heterogeneity among included studies (I2=99%), but subgroup analysis did not explain this heterogeneity. Conclusion: Consistent with other published studies, the average response rate in surveys done with Portuguese GPs was 56%, with substantial variation among studies. Use of monetary incentives, one of the most effective strategies to increase response rates, was not present in any of the included studies.

Influence of Paper Color and a Monetary Incentive on Response Rate

2004 ◽  
Vol 95 (2) ◽  
pp. 432-434 ◽  
Author(s):  
Keith A. King ◽  
Jennifer L. Vaughan
Keyword(s):  
Eating Disorders ◽  
Response Rate ◽  
Athletic Trainers ◽  
Response Rates ◽  
Monetary Incentive ◽  
Survey Response ◽  
Green Paper ◽  
Survey Response Rate

This study examined whether survey response rate differed based on the color of the paper the survey was printed on (blue vs green) and presence of a monetary incentive. A 4-page survey on eating disorders was mailed to Division 1A and 1AA college head athletic trainers ( N = 223) with half of the surveys on blue paper and half on green paper. Half of the athletic trainers ( n = 111) received a $1.00 monetary incentive, and half ( n = 112) received no monetary incentive. A total of 166 (71%) athletic trainers returned completed surveys. Response rates did not differ based on survey color but did differ based on presence of a monetary incentive. Athletic trainers who received a monetary incentive were significantly more likely than those who did not to return completed surveys (86% vs 63%, respectively).

scholarly journals Effectiveness of SMS messaging for diarrhoea measurement: a factorial cross-over randomised controlled trial

2020 ◽  
Author(s):  
Ryan Trevor Titus Rego ◽  
Samuel Watson ◽  
Philbert Ishengoma ◽  
Philemon Langat ◽  
Hezekiah Pireh Otieno ◽  
...  
Keyword(s):  
Randomised Controlled Trial ◽  
Text Messaging ◽  
Response Rate ◽  
Financial Incentive ◽  
Controlled Trial ◽  
Response Rates ◽  
Lower Response ◽  
Lower Response Rate ◽  
The Mean ◽  
Randomised Controlled

Abstract Background Text messaging systems are used to collect data on symptom prevalence. Using a text messaging system, we evaluated the effects of question load, question frequency, and financial incentive on response rates and reported infant diarrhoea rates in an infant diarrhoea survey. Methods We performed a factorial cross-over randomised controlled trial of an SMS surveying system for infant diarrhoea surveillance with treatments: financial incentive (yes/no), question load (1-question/3-question), and questioning frequency (daily/fortnightly). Participants progressed through all treatment combinations over eight two-week rounds. Data were analysed using multivariable logistic regressions to determine the impacts of the treatments on the response rates and reported diarrhoea rates. Attitudes were explored through qualitative interviews. Results For the 141 participants, the mean response rate was 47%. In terms of percentage point differences (ppd), daily questioning was associated with a lower response rate than fortnightly (-1·2[95%CI:-4·9,2·5]); high (3-question) question loads were associated with a lower response rate than low (1-question) question loads (-7·0[95%CI:-10·8,-3·1]); and financial incentivisation was associated with a higher response rate than no financial incentivisation (6·4[95%CI:2·6,10·2]). The mean two-week diarrhoea rate was 36·4%. Daily questioning was associated with a higher reported diarrhoea rate than fortnightly (29·9[95%CI:22·8,36·9]); with little evidence for impact by incentivisation or question load. Conclusions Close to half of all participants responded to the SMS survey. Daily questioning evoked a statistically higher rate of reported diarrhoea, while financial incentivisation and low (1-question) question loads evoked higher response rates than no incentive and high (3-question) question loads respectively. Trial Registration The protocol was registered on ISRCTN on the 20 th of March 2019 under number ISRCTN11410773 .

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