Pedicle screw placement accuracy in robot-assisted versus image-guided freehand surgery of thoraco-lumbar spine (ROBARTHRODESE): study protocol for a single-centre randomized controlled trial.

BACKGROUND: Robotic spinal surgery may result in better pedicle screw placement accuracy, and reduction in radiation exposure and length of stay, compared to freehand surgery. The purpose of this randomized controlled trial (RCT) is to compare screw placement accuracy of robot-assisted surgery with integrated 3D computer-assisted navigation versus freehand surgery with 2D fluoroscopy for arthrodesis of the thoraco-lumbar spine. METHODS: This is a single-centre evaluator-blinded RCT with a 1:1 allocation ratio. Participants (n = 300) will be randomized into two groups, robot-assisted (Mazor X Stealth Edition) versus freehand, after stratification based on the planned number of pedicle screws needed for surgery. The primary outcome is the proportion of pedicle screws placed with grade A accuracy (Gertzbein-Robbins classification) on postoperative computed tomography images. The secondary outcomes are intervention time, operation room occupancy time, length of stay, estimated blood loss, surgeon's radiation exposure, screw fracture/loosening, superior-level facet joint violation, complication rate, reoperation rate on the same level or one level above, functional and clinical outcomes (Oswestry Disability Index, pain, Hospital Anxiety and Depression Scale, sensory and motor status) and cost-utility analysis. DISCUSSION: This RCT will provide insight into whether robot-assisted surgery with the newest generation spinal robot yields better pedicle screw placement accuracy than freehand surgery. Potential benefits of robot-assisted surgery include lower complication and revision rates, shorter length of stay, lower radiation exposure and reduction of economic cost of the overall care. TRIAL REGISTRATION: ClinicalTrials.gov NCT05553028. Registered on September 23, 2022.

The safe and effective use of supercritical CO2-processed bone allografts for cervical and lumbar interbody fusion: A retrospective study.

Introduction: The clinical efficacy and safety of supercritical CO2-processed bone allografts prepared from living donors has yet to be confirmed in spinal surgery. Here we report our clinical and surgical experience of using supercritical CO2-processed bone allografts for lumbar and cervical fusion. Methods: Sixteen patients underwent one or two level anterior cervical discectomy and fusion and 37 patients underwent anterior retroperitoneal route lumbar fusion using bone allografts processed using supercritical CO2 extraction combined with chemical viral inactivation. Fusion success was assessed radiographically in the immediate postoperative period and at one month, six months, one year, and three years postoperatively. Function and pain were assessed using visual analog scales, Odom's criteria, the neck disability index (NDI), and the Oswestry disability index (ODI). Results: At a mean of 43 and 47 months postoperatively, 95.3% and 90.5% of cervical and lumbar fusion patients had radiographic evidence of bone fusion, respectively. Over 80% of patients reported good to excellent outcomes according to Odom's criteria, the perception of pain significantly decreased, and the mean NDI and ODI scores significantly improved at the last follow-up compared with before the operations. There were no safety concerns. For the cervical group, the mean NDI score improved from 26.3 ± 6.01 preoperatively to 15.00 ± 8.03 and 17.60 ± 13.95 at immediate post-op (p = 0.02) and last follow-up visits (p = 0.037) respectively. For the lumbar cases, the mean ODI score improved from 28.31 ± 6.48 preoperatively to 14.68 ± 5.49 (p < 0.0001) and 12.54 ± 10.21 (p < 00001) at immediate post-op and last follow-up visits respectively. Conclusion: Within the limitations of this study, the use of supercritical CO2-processed bone allografts resulted in satisfactory clinical outcomes and fusion rates with acceptable safety for both cervical and lumbar surgeries.

Evidence of antibodies against SARS-CoV-2 in wild mustelids from Brittany (France).

In the French region of Brittany, mainly in the department of the Côtes d'Armor, during the first half of 2021, seropositivity for SARS-CoV-2 was detected in five wild mustelids out of 33 animals tested (15.6%). Anti-SARS-CoV-2 IgG was detected against at least four out of five recombinant viral proteins (S1 receptor binding domain, nucleocapsid, S1 subunit, S2 subunit and spike) in three pine martens (Martes martes) and in two badgers (Meles meles) using the automated western blot technique. An ELISA test also identified seropositive cases, although these did not align with western blot results. Although the 171 qPCRs carried out on samples from the 33 mustelids were all negative, these preliminary results from this observational study nevertheless bear witness to infections of unknown origin. The epidemiological surveillance of Covid-19 in wildlife must continue, in particular with effective serology tools.

Structural Dynamics of the SARS-CoV-2 Spike Protein: A 2-Year Retrospective Analysis of SARS-CoV-2 Variants (from Alpha to Omicron) Reveals an Early Divergence between Conserved and Variable Epitopes.

We analyzed the epitope evolution of the spike protein in 1,860,489 SARS-CoV-2 genomes. The structural dynamics of these epitopes was determined by molecular modeling approaches. The D614G mutation, selected in the first months of the pandemic, is still present in currently circulating SARS-CoV-2 strains. This mutation facilitates the conformational change leading to the demasking of the ACE2 binding domain. D614G also abrogated the binding of facilitating antibodies to a linear epitope common to SARS-CoV-1 and SARS-CoV-2. The main neutralizing epitope of the N-terminal domain (NTD) of the spike protein showed extensive structural variability in SARS-CoV-2 variants, especially Delta and Omicron. This epitope is located on the flat surface of the NTD, a large electropositive area which binds to electronegatively charged lipid rafts of host cells. A facilitating epitope located on the lower part of the NTD appeared to be highly conserved among most SARS-CoV-2 variants, which may represent a risk of antibody-dependent enhancement (ADE). Overall, this retrospective analysis revealed an early divergence between conserved (facilitating) and variable (neutralizing) epitopes of the spike protein. These data aid in the designing of new antiviral strategies that could help to control COVID-19 infection by mimicking neutralizing antibodies or by blocking facilitating antibodies.

Deltamethrin Persistence on Textiles Used to Make Visual Targets for Tsetse Fly Control is Positively Correlated With Their Polyester Content.

Insecticide-impregnated traps and visual targets are used for tsetse (Diptera, Glossinidae) population control. Such devices are made with textiles and deltamethrin is frequently the insecticide of choice. However, persistence of an insecticide on textiles is affected by exposure to weather. Here we examine the effect of weathering on the capacity of four textiles with increasing proportions of polyester (0, 35, 65, and 100%) with cotton and viscose to retain deltamethrin. Textiles tested were those used to make visual targets in a pan-African program to maximize target efficiency for controlling tsetse vectors of African trypanosomiasis. Following impregnation in an aqueous suspension of deltamethrin at 1,000 mg/m2, textiles were weathered for 18 mo at Lambwe Valley, Kenya and sampled every 3 mo to make knockdown tests on the tsetse fly Glossina pallidipes Austen. Deltamethrin content of the textiles was established using gas chromatography mass-spectrometry at impregnation and after 9 mo of weathering. Textiles with higher proportions of polyester retained deltamethrin better: respectively, 100% polyester and 65:35 polyester/viscose textiles retained deltamethrin at 17 and 11 mg/m2 9-mo post-treatment that caused 100% knockdown in G. pallidipes after 1 h, and killed 67 and 47% of flies, respectively, after 24 h. Eighteen-month weathered 100% polyester treated textile still knocked down all tsetse exposed to it within 2 h. The LD50 for deltamethrin on filter paper for G. pallidipes was estimated at 28.8 mg/m2, indicating that deltamethrin is more available on polyester to kill tsetse.

Large concomitant outbreaks of acute gastroenteritis emergency visits in adults and food-borne events suspected to be linked to raw shellfish, France, December 2019 to January 2020.

On 27 December 2019, the French Public Health Agency identified a large increase in the number of acute gastroenteritis and vomiting visits, both in emergency departments and in emergency general practitioners' associations providing house-calls. In parallel, on 26 and 27 December, an unusual number of food-borne events suspected to be linked to the consumption of raw shellfish were reported through the mandatory reporting surveillance system. This paper describes these concomitant outbreaks and the investigations' results.

Spectral sensitivity of L2 biotype in the Thrips tabaci cryptic species complex.

The onion thrips, Thrips tabaci (Lindeman, 1889), is a cosmopolitan pest of economic importance on a wide range of crops. Despite being one of the most studied thrips species, there is very limited knowledge available about its ability to perceive light. The T. tabaci cryptic species complex consists of a tobacco-associated (T) and two leek-associated (L1, L2) biotypes. We made electroretinogram recordings on the most widespread thelytokous (where unfertilized eggs produce females) T. tabaci L2 biotype and measured attraction to light sources in this biotype as a function of wavelength in behavioural experiments. The spectral sensitivity of the T. tabaci L2 biotype shows a unimodal curve peaking at λmax = 521 nm. Contrary to this spectral sensitivity curve, L2 biotype attraction in an arena is bimodal with local maxima at 368 nm (UV) and 506-520 nm (green) being practically of the same magnitude. Although being similar to the arrhenotokous (where unfertilized eggs produce males) L1 biotype in phototaxis, significant differences regarding photoreceptor cell responses emerged. This study contributes to our understanding of light perception in Thysanoptera as well as to the development of more effective monitoring tools for this economically important pest species.

Standardising visual control devices for Tsetse: East and Central African Savannah species Glossina swynnertoni, Glossina morsitans centralis and Glossina pallidipes.

BACKGROUND: This study focused on the savannah tsetse species Glossina swynnertoni and G. morsitans centralis, both efficient vectors of human and animal trypanosomiasis in, respectively, East and Central Africa. The aim was to develop long-lasting, practical and cost-effective visually attractive devices that induce the strongest landing responses in these two species for use as insecticide-impregnated tools in population suppression. METHODS AND FINDINGS: Trials were conducted in different seasons and years in Tanzania (G. swynnertoni) and in Angola and the Democratic Republic of the Congo (DRC, G. m. centralis) to measure the performance of traps (pyramidal and epsilon) and targets of different sizes, shapes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used to catch flies landing on devices at the remote locations to compare tsetse-landing efficiencies. Landing rates by G. m. centralis in both Angola and the DRC were highest on blue-black 1 m2 oblong and 0.5 m2 square and oblong targets but were not significantly different from landings on the pyramidal trap. Landings by G. swynnertoni on 0.5 m2 blue-black oblong targets were likewise not significantly lower than on equivalent 1 m2 square targets. The length of target horizontal edge was closely correlated with landing rate. Blue-black 0.5 m2 targets performed better than equivalents in all-blue for both G. swynnertoni and G. m. centralis, although not consistently. Baiting with chemicals increased the proportion of G. m. centralis entering pyramidal traps. CONCLUSIONS: This study confirms earlier findings on G. swynnertoni that smaller visual targets, down to 0.5 m2, would be as efficient as using 1 m2 targets for population management of this species. This is also the case for G. m. centralis. An insecticide-impregnated pyramidal trap would also constitute an effective control device for G. m. centralis.

Identification of novel bioinspired synthetic mosquito repellents by combined ligand-based screening and OBP-structure-based molecular docking.

In this work we report a fast and efficient virtual screening protocol for discovery of novel bioinspired synthetic mosquito repellents with lower volatility and, in all likelihood, increased protection time as compared with their plant-derived parental compounds. Our screening protocol comprises two filtering steps. The first filter is based on the shape and chemical similarity to known plant-derived repellents, whereas the second filter is based on the predicted similarity of the ligand's binding mode to the Anopheles gambiae odorant binding protein (AgamOBP1) relative to that of DEET and Icaridin to the same OBP. Using this protocol, a chemical library containing 42,755 synthetic molecules was screened in silico and sixteen selected compounds were tested for their affinity to AgamOBP1 in vitro and repellence against A. gambiae female mosquitoes using a warm-body repellent assay. One of them showed DEET-like repellence (91%) but with significantly lower volatility (2.84 × 10-6 mmHg) than either DEET (1.35 × 10-3 mmHg) or its parental cuminic acid (3.08 × 10-3 mmHg), and four other compounds were found to exhibit repellent indices between 69 and 79%. Overall, a correlation was not evident between repellence and OBP-binding strength. In contrast, a correlation between binding mode and repellence was found.

Vision and genesis of survival strategies in tsetse flies: A laboratory study.

Organisms respond to environmental stimuli in ways that optimize survival and reproduction. Tsetse fly life-history is characterized by high investment in progeny by the pregnant female and low birth rate. This places constraints on tsetse populations across the sub-Saharan biotopes they colonize where extreme climatic conditions militate against survival. Controlling metabolic rate is crucial in biotopes where daily swings in temperature can exceed 20 °C. Tsetse acquire their nutrient requirements from the blood meal. These diurnal flies are otherwise confined for most of their lives to perching sites in the shade. At these locations they are simultaneously threatened by vertebrate and invertebrate predators. Here we describe behaviours of the East African tsetse Glossina pallidipes Austen (Diptera: Glossinidae) that permit it to reduce risk daily. Newly-emerged flies remain immobile at emergence in the photophase but scotophase-emerging flies walk away within seconds to climb (negative geotaxis) vertical substrates to find a perch off the ground. Flies of all ages show the ability to fly in almost total darkness (1.10-5 lux) in the scotophase to perch on the upper side of horizontally suspended 1 cm diameter bars, simulating branches of vegetation, but perch under the same bars during the photophase. This underlines the predilection of tsetse for objects with a linear aspect that provide a vantage point and shade. Mature G. pallidipes can discriminate between horizontally suspended bars of different diameter and shape. Flicker fusion frequency values established by optomotor and retinogram recordings reveal a higher visual acuity in mature compared to newly-emerged tsetse.

Odorant-binding protein-based identification of natural spatial repellents for the African malaria mosquito Anopheles gambiae.

There is increasing interest in the development of effective mosquito repellents of natural origin to reduce transmission of diseases such as malaria and yellow fever. To achieve this we have employed an in vitro competition assay involving odorant-binding proteins (OBPs) of the malaria mosquito, Anopheles gambiae, with a predominantly female expression bias to identify plant essential oils (EOs) containing bioactive compounds that target mosquito olfactory function. EOs and their fractions capable of binding to such OBPs displayed repellence against female mosquitoes in a laboratory repellent assay. Repellent EOs were subjected to gas chromatographic analysis linked to antennogram (EAG) recordings from female A. gambiae to identify the biologically active constituents. Among these compounds cumin alcohol, carvacrol, ethyl cinnamate and butyl cinnamate proved as effective as DEET at an equivalent dose in the repellent assay, and combinations of carvacrol with either butyl cinnamate or cumin alcohol proved to be significantly more effective than DEET in the assay. When tested as spatial repellents in experimental shelters housing sleeping humans in northern Nigeria a binary mixture of carvacrol plus cumin alcohol caused mosquitoes to leave shelters in significantly higher numbers to those induced by DEET in female Anopheles spp. and in numbers equivalent to that of DEET in Culex spp. mosquitoes. These findings indicate an approach for the identification of biologically active molecules of natural origin serving as repellents for mosquitoes.

Insecticidal and repellent properties of novel trifluoromethylphenyl amides II.

This project focused on the design, synthesis, and testing of trifluoromethylphenyl amides (TFMPAs) as potential mosquitocides and repellents. Fourteen compounds were evaluated for toxicity against larvae and adults of Aedes aegypti. Several compounds were toxic against Aedes aegypti (larval, adult and feeding bioassays) and Drosophila melanogaster (glass-surface contact assay), but were much less toxic than fipronil, with toxicity ratios ranging from 100-fold in the larval assay to 100,000-fold for topical application to adult insects. In repellency bioassays to determine minimum effective dosage (MED), compound N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-2,2,3,3,3-pentafluoropropanamide (7b) repelled Ae. aegypti females at lower concentration, 0.017 (±0.006) µmol/cm2, than N, N-diethyl-meta-toluamide (DEET) 0.026 (±0.005) µmol/cm2. 2-Chloro-N-(3-(trifluoromethyl)phenyl)acetamide (6a) performed better than DEET against two species of mosquitoes: it repelled Ae. aegypti females at 0.013 (±0.006) µmol/cm2 and Anopheles gambiae females (in a warm body repellent assay), at a standard exposure of 2 nmol/cm2. These studies revealed novel active structures that could further lead to compounds with better repellent activity.

Behavioral response of the malaria mosquito, Anopheles gambiae, to human sweat inoculated with axilla bacteria and to volatiles composing human axillary odor.

The responses of Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) to odors from male and female axillary sweat incubated with human axilla bacteria were recorded in a dual-choice olfactometer. Staphylococcus epidermidis was selected for its low odor-producing pattern, Corynebacterium jeikeium for its strong Nα-acylglutamine aminoacylase activity liberating carboxylic acids including (R)/(S)-3-hydroxy-3-methylhexanoic acid (HMHA) and Staphylococcus haemolyticus for its capacity to liberate sulfur-containing compounds including (R/S)-3-methyl-3-sulfanylhexan-1-ol (MSH). Anopheles gambiae behavioral responses were evaluated under (i) its responsiveness to take off and undertake sustained upwind flight and (ii) its discriminating capacity between the two olfactometer arms bearing a test odor in either one or both arms. Experiments were conducted in the presence of carbon dioxide pulses as a behavioral sensitizer. Anopheles gambiae clearly discriminated for the olfactometer arm conveying odor generated by incubating any of the three bacteria species with either male or female sweat. Whereas An. gambiae did not discriminate between male and female sterile sweat samples in the olfactometer, the mosquito consistently showed a preference for male sweat over female sweat incubated with the same bacterium, independent of the species used as inoculum. Sweat incubated with C. jeikeium rendered mosquitoes particularly responsive and this substrate elicited the strongest preference for male over female sweat. Tested on their own, neither HMHA nor MSH elicited a clear discriminating response but did affect mosquito responsiveness. These findings serve as a basis for further research on the odor-mediated anthropophilic host-seeking behavior of An. gambiae.

Anopheles gambiae females readily learn to associate complex visual cues with the quality of sugar sources.

The ability to learn plays a key role in tuning and adapting the behaviours of animals for their unpredictable biotopes. This also applies to insect vectors of disease. Anautogenous mosquitoes need to find both sugar and blood for survival and reproduction. Learning processes are expected to contribute to a mosquito's ability to undertake repeated feeding behaviours more efficiently with time, serving to decrease energy demands and avoid hazards. Here we report how visual learning by the Afrotropical malaria mosquito Anopheles gambiae allows it to readily associate visual cues with the quality of a sugar source. Circular black and white patterns were used as visual cues. An. gambiae females were conditioned in cages with a chequered pattern paired with sucrose and a concentric pattern paired with non-palatable sucrose-NaCl and with reverse combinations. Hours later, significantly higher numbers of feeding attempts were counted on sucrose paired with the chequered pattern following conditioning with the same combination. This was also the case on the concentric pattern paired with sucrose following conditioning with this combination. However, the effect was weaker than with sucrose paired with the chequered pattern. These findings indicate a differential capacity of visual stimuli to induce learning, explained in our experiments by a significantly higher mosquito appetence on sucrose paired with a chequered pattern that mimics floral shape. Training that induced a higher propensity for feeding attempts was found to allow the females to display a fast learning curve (<4min) on the less suitable concentric pattern paired with sucrose, several hours after conditioning on the chequered pattern paired with sucrose. This has important implications for mosquito behavioural ecology, suggesting that An. gambiae shows plasticity in its learning capacities that would allow it to readily turn to alternative sources for a sugar meal once initiated in the process by an appropriate stimulus combination.

Short-chain alkanes synergise responses of moth pests to their sex pheromones.

BACKGROUND: The use of sex pheromones for mating disruption of moth pests of crops is increasing worldwide. Efforts are under way to augment the efficiency and reliability of this control method by adding molecules derived from host plants to the sex attractants in dispensers. RESULTS: We show how attraction of the European grapevine moth, Lobesia botrana Den. & Schiff., and the codling moth, Cydia pomonella L., males to underdosed levels of their sex pheromones is increased by adding heptane or octane over a range of release rates. Pheromone-alkane mixtures enhance male recruitment by up to 30%, reaching levels induced by calling females, and shorten the flight time to the sex attractant by a factor of 2. CONCLUSION: The findings show the promise of using short-chain alkanes as pheromone synergists for mating disruption of insect pests of food crops. Alkane-pheromone combinations are expected to increase the competitiveness of dispensers with females, and to reduce the amount of pheromone needed for the control of these pests.

A new approach for cleansing geographical dataset using Levenshtein distance, prior knowledge and contextual information.

Epidemiological studies are necessary to take public health decisions. Their relevance depends on the quality of data. Doctors in continuous care collect a big amount of data that can be used for epidemiological purpose, but spatial data may be dirty; based on city names, the localization is imprecise, even more if it is misspelled. The only way to identify a city without ambiguity is to use its identifier, which can be retrieved by cleansing geographical textual data. In France, cities are organized in administrative zones called departments and some city names are shared by several cities in several departments. The clear identification of the department and the city name allows to deduce the city unique identifier and to make some spatial analysis such as epidemiological studies. In this paper, we propose a method to cleanse such data, using several steps. After having standardized the text to cleanse, we use the Levenshtein distance to generate a first set of propositions. Finally, the propositions are filtered, by removing the less likely candidates, so that it remains only one, which becomes the chosen city. Tested on a dataset of 9818 entries, we obtained 89.1% of concordance, whereas the standard Levenshtein distance obtained 70.5%. This demonstrates that our method has better results.

Sugar-sensitive neurone responses and sugar feeding preferences influence lifespan and biting behaviours of the Afrotropical malaria mosquito, Anopheles gambiae.

Floral nectar is the main source of carbohydrates for many insects including mosquitoes. Nonetheless, the physiological mechanisms underlying feeding on carbohydrates by the Afrotropical malaria mosquito Anopheles gambiae remain poorly understood. Here, we tested whether sugar sensitivity and sugar feeding preferences correlate with longevity in A. gambiae. We also tested whether feeding females on different sugar diets influences their biting behaviours. Electrophysiological recordings show that sugar neurones on the labella of females are most sensitive to sucrose, mixtures of glucose and fructose, and to melezitose; other sugars tested, including glucose and fructose presented alone, only weakly activate these taste neurones. Mosquitoes survive longest on sucrose, the most preferred sugar. Whereas feeding on a mixture of glucose and fructose is preferred over fructose or glucose alone, fructose supports higher longevity than either glucose or the mixture of the two hexoses. Females that had previously fed on glucose show a stronger biting response than those fed on sucrose, perhaps in an effort to compensate for their lower energetic state. These findings contribute to our understanding of the physiological basis of sugar feeding in A. gambiae and indicate how the sugar diet can affect laboratory-reared A. gambiae biting behaviours.

Management of a major atlanto-axial instability secondary to a lytic lesion of C2.

INTRODUCTION: Management of C1-C2 instability is very challenging, especially when tumoral lesions are involved. CASE REPORT: We present the case of a 65-year-old male, with a recently discovered small cell lung carcinoma, presenting progressive tetraparesis due to a secondary lesion involving the body of C2 with complete collapse of its anterior part and major C1-C2 instability in all planes. The patient underwent a reconstructive surgery of the upper cervical spine during two sessions. First, an emergency surgery was done by a high anterior cervical approach, where reconstruction of the body of C2 was done by an original technique using a C3 body to odontoid long screw with bone cement filling around the screw at the level of C2, and an anterior buttress plate put from C2 to C4. A posterior surgery was performed after 48 h to stabilize the spine posteriorly with C1 to C5 instrumentation. The patient recovered from his neurological symptoms, and underwent complementary adjuvant radiotherapy with chemotherapy later on. CONCLUSION: Literature is sparse on the treatment of major C1-C2 instability, especially when a secondary lesion is involved, the current case shows a successful treatment strategy with an original technique that was never described before in the literature. The patient was pain free at 1 year follow-up with a stable construct.

Standardizing visual control devices for tsetse flies: east African Species Glossina fuscipes fuscipes and Glossina tachinoides.

BACKGROUND: Riverine species of tsetse are responsible for most human African trypanosomiasis (HAT) transmission and are also important vectors of animal trypanosomiasis. This study concerns the development of visual control devices for two such species, Glossina fuscipes fuscipes and Glossina tachinoides, at the eastern limits of their continental range. The goal was to determine the most long-lasting, practical and cost-effective visually attractive device that induces the strongest landing responses in these species for use as insecticide-impregnated tools in vector population suppression. METHODS AND FINDINGS: Field trials were conducted in different seasons on G. f. fuscipes in Kenya, Ethiopia and the Sudan and on G. tachinoides in Ethiopia to measure the performance of traps and 2D targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used to enumerate flies at these remote locations to compare trapping efficiencies. The findings show that targets made from black and blue fabrics (either phthalogen or turquoise) covered with adhesive film render them equal to or more efficient than traps at capturing G. f. fuscipes and G. tachinoides. Biconical trap efficiency varied between 25% and 33% for the two species. Smaller 0.25 m×0.25 m phthalogen blue-black targets proved more efficient than the regular 1 m2 target for both species, by over six times for Glossina f. fuscipes and two times for G. tachinoides based on catches per m2. Overall, targets with a higher edge/surface area ratio were more efficient at capturing flies. CONCLUSIONS/SIGNIFICANCE: Taking into account practical considerations and fly preferences for edges and colours, we propose a 0.5×0.75 m blue-black target as a simple cost-effective device for management of G. f. fuscipes and G. tachinoides, impregnated with insecticide for control and covered with adhesive film for population sampling.

Amines from vertebrates guide triatomine bugs to resources.

Most triatomine bugs (Heteroptera: Reduviidae) are nest-living insects that require vertebrate blood or invertebrate haemolymph to complete their life cycle. Vertebrates accumulate excretory products in or near their nesting sites and we hypothesize that triatomines use emanations from such host wastes when searching for resources. Here we recount how triatomine bugs increase upwind locomotion on a servosphere in response to volatile amine constituents of vertebrate excretions. Fresh chicken faeces is strongly attractive to Rhodnius prolixus nymphs. Ammonia induces attraction and an increase in both speed and total path length by R. prolixus on the servosphere. Whereas ethylamine and dimethylamine attract R. prolixus, Triatoma infestans and Panstrongylus geniculatus, other amine constituents of vertebrate excretions such as isobutylamine and hexylamine induce R. prolixus nymphs to walk faster and for a longer period. These amines are derived from generally occurring metabolites of vertebrates and from gut flora metabolism. We conclude that amines and other products associated with nesting hosts serve as signals for foraging triatomines.