De bedwants: a bad bug?

2021 ◽  
Author(s):  
W.L.C. VAN HOOSTE
Keyword(s):  
Skin Lesions ◽  
Human Pathogens ◽  
Bed Bugs ◽  
Bed Bug ◽  
Early 21St Century ◽  
Cluster Configuration ◽  
The Face ◽  
Bites And Stings ◽  
Clinical Differential Diagnosis

The bed bug: a bad bug? The common bed bug, Cimex lectularius, is a bloodsucking ectoparasite which attacks mammals and is on the rise since the beginning of the early 21st century. They are brown and flat. Skin lesions appear after the painless bite, often during the predawn hours. Small, purpuric macules develop into erythematous, indurated papules on exposed areas of skin of the face, neck and extremities, and resolve over the course of 2 weeks. Often, a linear or cluster configuration of 3 to 4 lesions (‘breakfast, lunch and dinner’) appears. Pruritic wheal reactions represent a type 1 hypersensitivity reaction elicited by the parasite’s saliva antigens. The clinical differential diagnosis is broad and may include other insect and arthropod bites and stings, scabies infestation, dermatitis herpetiformis, ecthyma, etc. There is no evidence that bed bugs are vectors and transmit human pathogens. They are responsible for considerable physical irritation and significant psychological distress. Very rarely, the patient could develop anemia or anaphylaxis. Control involves treating both the patient’s symptoms and the cause by the eradication of the infestation, a challenge that may require a professional exterminator for an integrated pest management strategy. “Good night, sleep tight, don’t let the bed bugs bite!”

Bed bugs (Cimex lectularius): Biology and their Role as Pests to Humans

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Dreann Nicole Fedor
Keyword(s):  
Side Effects ◽  
Blood Feeding ◽  
Skin Lesions ◽  
Cimex Lectularius ◽  
Control Methods ◽  
Extreme Temperatures ◽  
Bed Bugs ◽  
Pyrethroid Insecticides ◽  
Bed Bug ◽  
Unique Biology

  Bed bugs (Cimex lectularius) are blood feeding ectoparasites that have evolved as human pests due to their unique biology and reproduction. Common side effects of bed bug bites include: skin lesions, localized inflammation, itchiness and anxiety. There are numerous control methods to reduce bed bug populations such as vacuuming, steaming, laundering, exposure to extreme temperatures and chemical eradication methods. Bed bugs have become resistant to pyrethroid insecticides and DDT, supporting the cosmopolitan reemergence of bed bugs in the last couple decades.

Evidence for a shear mechanism for the precipitation of γ-zirconium hydride in zirconium

1978 ◽  
Vol 36 (1) ◽  
pp. 658-659
Author(s):  
G.J.C. Carpenter
Keyword(s):  
Elevated Temperature ◽  
Strain Field ◽  
Zirconium Hydride ◽  
Zirconium Atom ◽  
Atom Diffusion ◽  
Solvus Temperature ◽  
Hexagonal Close Packed ◽  
Partial Dislocations ◽  
The Face

In zirconium-hydrogen alloys, rapid cooling from an elevated temperature causes precipitation of the face-centred tetragonal (fct) phase, γZrH, in the form of needles, parallel to the close-packed <1120>zr directions (1). With low hydrogen concentrations, the hydride solvus is sufficiently low that zirconium atom diffusion cannot occur. For example, with 6 μg/g hydrogen, the solvus temperature is approximately 370 K (2), at which only the hydrogen diffuses readily. Shears are therefore necessary to produce the crystallographic transformation from hexagonal close-packed (hep) zirconium to fct hydride.The simplest mechanism for the transformation is the passage of Shockley partial dislocations having Burgers vectors (b) of the type 1/3<0110> on every second (0001)Zr plane. If the partial dislocations are in the form of loops with the same b, the crosssection of a hydride precipitate will be as shown in fig.1. A consequence of this type of transformation is that a cumulative shear, S, is produced that leads to a strain field in the surrounding zirconium matrix, as illustrated in fig.2a.

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.

Effects of Analgesics on Delayed Postherpetic Pain in Mice

2002 ◽  
Vol 96 (5) ◽  
pp. 1168-1174 ◽  
Author(s):  
Ichiro Takasaki ◽  
Atsushi Sasaki ◽  
Tsugunobu Andoh ◽  
Hiroshi Nojima ◽  
Kimiyasu Shiraki ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Postherpetic Neuralgia ◽  
Herpes Simplex Virus Infection ◽  
Skin Lesions ◽  
Cutaneous Lesions ◽  
Acyclovir Treatment ◽  
Simplex Virus ◽  
Von Frey Filaments

Background Postherpetic neuralgia is pain that persists long after the disappearance of the cutaneous lesions of herpes zoster. However, the mechanisms of this delayed pain are unclear. Herpes simplex virus infection induces cutaneous lesions and pain-related responses in mice. The authors examined whether such responses would persist after the disappearance of the cutaneous lesions and whether some analgesics would be effective against them. Methods Female BALB/c mice were inoculated with herpes simplex virus type 1 on the unilateral hind paw. Pain-related responses of hind paw were determined using von Frey filaments. Beginning 5 days after inoculation, mice were given perorally the antiherpes agent acyclovir five times a day for 7 days. Effects of morphine (3-5 mg/kg subcutaneously), gabapentin (30-100 mg/kg perorally), mexiletine (10-30 mg/kg intraperitoneally), and diclofenac (30 mg/kg intraperitoneally) on pain-related responses were examined on days 25-35 after inoculation. Results Viral inoculation induced cutaneous lesions and pain-related responses beginning on day 5 after inoculation. Acyclovir treatment healed all skin lesions by day 15 after inoculation. Approximately half of the mice given acyclovir showed pain-related responses at least until day 40 after inoculation. Morphine, gabapentin, and mexiletine dose-dependently inhibited pain-related responses, but diclofenac had no effects. Conclusions The authors show a mouse model of delayed postherpetic pain. This may be useful for manifesting the mechanisms of postherpetic neuralgia and the factors contributing to the transition from acute herpetic pain to delayed postherpetic pain. This may also be useful for the development of new analgesics against postherpetic neuralgia.

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.

scholarly journals On Using a Mobile Application to Support Teledermatology: A Case Study in an Underprivileged Area in Colombia

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Juan Pablo Sáenz ◽  
Mónica Paola Novoa ◽  
Darío Correal ◽  
Bell Raj Eapen
Keyword(s):  
Rural Areas ◽  
Mobile Applications ◽  
Mobile Application ◽  
Correct Diagnosis ◽  
Skin Lesions ◽  
Healthcare Personnel ◽  
Combined Use ◽  
Forest Regions ◽  
The Face

Background. The use of mobile applications in dermatology to support remote diagnosis is gaining acceptance, particularly in rural areas, where dermatology services are commonly managed by healthcare personnel with no specialty training. Moreover, ontologies—sets of concepts that represent knowledge in a given domain—are increasingly being used to support medical diagnosis. A specific case is ONTODerm: an ontology to aid dermatological diagnosis. However, there is little information on the combined use of mobile applications and ontologies as support solutions in dermatology. Objective. Assessing the reliability of ONTODerm as a tool to support remote dermatological diagnosis when used together with a mobile dermatological application in underprivileged areas. Methods. A mobile application that allows characterization of skin lesions was developed, and the information about the lesions was sent to ONTODerm. An exploratory study was conducted in a remote area without access to a dermatologist. A total of 64 dermatological queries were recorded in the application and consulted with ONTODerm. Later, an experienced dermatologist evaluated the characterization and diagnosis of each query to determine the accuracy of the system. Results. The results showed that the probability of obtaining a correct diagnosis was between 64.4% and 85.6% with a confidence interval of 95%. A higher accuracy rate was obtained when the skin lesion occurred on the face or when its border was categorized as poorly demarcated. Conclusions. This study demonstrates the implementation of a teledermatology strategy based on mobile applications and domain ontology-driven knowledge base to provide timely assistance to healthcare professionals. This approach was found to be pertinent in the Colombian rural context, particularly in forest regions, where dermatology specialists are not available. The results of this article do not represent a final validation of the proposed approach; they suggest how the ontology can be improved to effectively support medical staff in marginalized regions.

Management of a Large Arteriovenous Fistula in the Face: A Case of Neurofibromatosis Type 1

1997 ◽  
Vol 39 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Mustafa Yilmaz ◽  
Emel Ada ◽  
Haluk Vayvada ◽  
Ali Barutçu
Keyword(s):  
Arteriovenous Fistula ◽  
Neurofibromatosis Type 1 ◽  
Neurofibromatosis Type ◽  
The Face

scholarly journals Prevalence and risk of appearence of skin lesions considered to be cutaneous markers of diabetes in a population group in bihor county

2012 ◽  
Vol 19 (3) ◽  
pp. 285-290
Author(s):  
Denisa Kovacs ◽  
Luiza Demian ◽  
Aurel Babeş
Keyword(s):  
Type 2 Diabetes ◽  
Type 1 Diabetes ◽  
Skin Lesion ◽  
Skin Diseases ◽  
Population Group ◽  
Skin Lesions ◽  
Diabetic Patients ◽  
Cutaneous Lesions

Abstract Objectives: The aim of the study was to calculate the prevalence rates and risk ofappearance of cutaneous lesions in diabetic patients with both type-1 and type-2diabetes. Material and Method: 384 patients were analysed, of which 47 had type-1diabetes (T1DM), 140 had type-2 diabetes (T2DM) and 197 were non-diabeticcontrols. Results: The prevalence of the skin lesions considered markers of diabeteswas 57.75% in diabetics, in comparison to 8.12% in non-diabetics (p<0.01). The riskof skin lesion appearance is over 7 times higher in diabetic patients than in nondiabetics.In type-1 diabetes the prevalence of skin lesions was significantly higherthan in type-2 diabetes, and the risk of skin lesion appearance is almost 1.5 timeshigher in type-1 diabetes than type-2 diabetes compared to non-diabetic controls.Conclusions: The diabetic patients are more susceptible than non-diabetics todevelop specific skin diseases. Patients with type-1 diabetes are more affected.

Anatomic patterning in the expression of vestibulosympathetic reflexes

2000 ◽  
Vol 279 (1) ◽  
pp. R109-R117 ◽  
Author(s):  
I. A. Kerman ◽  
B. J. Yates ◽  
R. M. McAllen
Keyword(s):  
Relative Proportion ◽  
Vestibular Stimulation ◽  
Nerve Fibers ◽  
Spike Shape ◽  
The Face ◽  
Nerve Fascicle ◽  
The Difference ◽  
Vestibulosympathetic Reflexes

To investigate the possibility that expression of vestibulosympathetic reflexes (VSR) is related to a nerve's anatomic location rather than its target organ, we compared VSR recorded from the same type of postganglionic fiber [muscle vasoconstrictor (MVC)] located at three different rostrocaudal levels: hindlimb, forelimb, and face. Experiments were performed on chloralose-anesthetized cats, and vestibular afferents were stimulated electrically. Single MVC unit activity was extracted by spike shape analysis of few-fiber recordings, and unit discrimination was confirmed by autocorrelation. Poststimulus time histogram analysis revealed that about half of the neurons were initially inhibited by vestibular stimulation (type 1 response), whereas the other MVC fibers were initially strongly excited (type 2 response). MVC units with types 1 and 2 responses were present in the same nerve fascicle. Barosensitivity was equivalent in the two groups, but fibers showing type 1 responses fired significantly faster than those giving type 2 responses (0.29 ± 0.04 vs. 0.20 ± 0.02 Hz). Nerve fibers with type 1 responses were most common in the hindlimb (21 of 29 units) and least common in the face (2 of 11 units), the difference in relative proportion being significant ( P < 0.05, χ2 test). These results support the hypothesis that VSR are anatomically patterned.

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