Human skin triglycerides prevent bed bug (Cimex lectularius L.) arrestment.

Bed bugs (Cimex lectularius) have proliferated globally and have become one of the most challenging pests to control indoors. They are nocturnal and use multiple sensory cues to detect and orient towards their human hosts. After feeding, usually on a sleeping human, they return to a shelter on or around the sleeping surface, but not directly on the host. We hypothesized that although human skin odors attract hungry bed bugs, human skin compounds may also prevent arrestment on hosts. We used arrestment assays to test human skin swabs, extracts from human skin swabs, and pure compounds identified from human skin swabs. When given a choice, bed bugs preferred to arrest on substrates not previously conditioned by humans. These responses were consistent among laboratory-reared and apartment-collected bed bugs. The compounds responsible for this behavior were found to be extractable in hexane, and bed bugs responded to such extracts in a dose-dependent manner. Bioassay-guided fractionation paired with thin-layer chromatography, GC-MS, and LC-MS analyses suggested that triglycerides (TAGs), common compounds found on human skin, were preventing arrestment on shelters. Bed bugs universally avoided sheltering in TAG-treated shelters, which was independent of the number of carbons or the number of double bonds in the TAG. These results provide strong evidence that the complex of human skin compounds serve as multifunctional semiochemicals for bed bugs, with some odorants attracting host-seeking stages, and others (TAGs and possibly other compounds) preventing bed bug arrestment. Host chemistry, environmental conditions and the physiological state of bed bugs likely influence the dual nature behavioral responses of bed bugs to human skin compounds.

Mating and starvation modulate feeding and host-seeking responses in female bed bugs, Cimex lectularius.

Reproductive fitness and survival are enhanced by adaptive behaviors that are modulated by internal physiological states and external social contexts. The common bed bug, Cimex lectularius, is an obligate hematophagous ectoparasite that requires host blood for growth, development, and reproduction. We investigated how mating, starvation and social interactions affect host-seeking, blood feeding, oviposition, and survival of female bed bugs. The percentage of females that fed and the amount of blood they ingested were greater in mated females (90-100%) than in unmated females (48-60%). Mating state also modulated the female's orientation towards human skin odor in an olfactometer; more mated (69%) than unmated (23%) females responded to human odors. The response rate of unmated females (60%) to skin odor increased with longer starvation period, while the opposite pattern was observed in mated females (20%). Although fecundity after a single blood meal was unaffected by long or short residence and interaction with males, females subjected to frequent copulation attempts had lower survivorship and lifespan than females housed with males for only 24 h. Taken together, these results indicate that by adaptively and coordinately expressing behaviors based on the internal physiological state, females maximize their survival and reproductive fitness.

Dynamics of bed bug infestations and control under disclosure policies.

Bed bugs have reemerged in the United States and worldwide over recent decades, presenting a major challenge to both public health practitioners and housing authorities. A number of municipalities have proposed or initiated policies to stem the bed bug epidemic, but little guidance is available to evaluate them. One contentious policy is disclosure, whereby landlords are obligated to notify potential tenants of current or prior bed bug infestations. Aimed to protect tenants from leasing an infested rental unit, disclosure also creates a kind of quarantine, partially and temporarily removing infested units from the market. Here, we develop a mathematical model for the spread of bed bugs in a generalized rental market, calibrate it to parameters of bed bug dispersion and housing turnover, and use it to evaluate the costs and benefits of disclosure policies to landlords. We find disclosure to be an effective control policy to curb infestation prevalence. Over the short term (within 5 years), disclosure policies result in modest increases in cost to landlords, while over the long term, reductions of infestation prevalence lead, on average, to savings. These results are insensitive to different assumptions regarding the prevalence of infestation, rate of introduction of bed bugs from other municipalities, and the strength of the quarantine effect created by disclosure. Beyond its application to bed bugs, our model offers a framework to evaluate policies to curtail the spread of household pests and is appropriate for systems in which spillover effects result in highly nonlinear cost-benefit relationships.

Infestação e controle de Cimex lectularius em abrigos públicos no município de Belo Horizonte/MG

Nos últimos anos vários autores têm relatado a ressurgência de infestações por percevejos de cama ao redor do mundo. Em meados de 2013 foi detectada a infestação por Cimex lectularius em abrigos municipais de Belo Horizonte/MG. Diversas ações foram direcionadas para o controle da praga, tais como a troca de colchões e o uso de inseticida da classe dos piretróides, mas a população de insetos não diminuiu. O objetivo desse trabalho foi caracterizar a infestação de C. lectulariusnos abrigos públicos do município de Belo Horizonte/MG e propor ações de controle. As 16 ocorrências de infestações registradas entre 2010 e 2016 foram georreferenciadas pelo software MapInfo Professional – Versão 10.0. Além disso, foram realizadas vistorias em quatro abrigos públicos municipais infestados para a caracterização dos perfis epidemiológicos da infestação nesses locais. Também foram realizados testes de contato com 10 inseticidas comerciais em laboratório. Nesses bioensaios de laboratório utilizaram-se 30 percevejos de cama adultos coletados em dois abrigos municipais em dois momentos diferentes que foram expostos por 24 horas a papéis impregnados com inseticidas, realizando-se a leitura da mortalidade 24 horas após a exposição. Por fim, foram realizados testes de campo em um abrigo público infestado utilizando-se os produtos que apresentaram os melhores resultados em laboratório. Nesses bioensaios de campo consideraram-se as camas como as unidades de estudo e realizaram-se vistorias antes e depois da borrifação com os produtos químicos. Baseado nessas informações foi proposta uma metodologia de controle

As ocorrências de infestações por cimicídeos se encontraram dispersas pelo município, se concentrando na regional Centro-Sul. Os quatro abrigos municipais estudados apresentaram níveis de infestações diferentes, sendo influenciado pela estrutura física e pela dinâmica de funcionamento de cada local. O Albergue Tia Branca apresentou a pior situação. Os testes em laboratório mostraram que apenas o carbamato Propoxur 1% apresentou mortalidade de 100% dos insetos expostos e houve resistência a quase todos os produtos formulados com a classe dos piretróides. Dentre os piretróides, apenas a Bifentrina 20% apresentou resultado promissor. Os testes em campo mostraram que foi possível eliminar as infestações com o uso combinado de dois carbamatos. A metodologia de controle proposta pressupõe que todo o ambiente infestado deve ser borrifado com inseticidas de ação residual a cada três meses e necessita permanecer interditado por sete dias. Apesar de não haver registrado o aumento no número de infestações por cimicídeos na capital mineira, a situação é preocupante nos albergues municipais. Além disso, a resistência dos insetos a vários inseticidas disponíveis no mercado e a dificuldade de controlar as infestações torna o problema relevante. É imprescindível que se institua no sistema de saúde municipal uma rotina de vigilância entomológica, para que as infestações sejam prevenidas, descobertas precocemente e controladas

Bed bugs and possible transmission of human pathogens: a systematic review.

The global population of bed bugs (Cimex lectularius and Cimex hemipterus, family Cimicidae) has undergone a significant resurgence since the late 1990s. This is likely due to an increase in global travel, trade, and the number of insecticide-resistant bed bugs. The global bed bug population is estimated to be increasing by 100-500 % annually. The worldwide spread of bed bugs is concerning, because they are a significant socioeconomic burden and a major concern to public health. According to the United States Environmental Protection Agency, bed bugs are "a pest of significant health importance." Additionally, 68 % of U.S. pest professionals reported that bed bugs are the most challenging pest to treat. Upwards of 45 disease pathogens have been reported in bed bugs. Recent studies report that bed bugs may be competent vectors for pathogens, such as Bartonella quintana and Trypanosoma cruzi. However, public health reports have thus far failed to produce evidence that major infectious disease outbreaks have been associated with bed bugs. Since many disease pathogens have previously been reported in bed bugs and the worldwide bed bug population is now drastically increasing, it stands to reason to wonder if bed bugs might transmit human pathogens. This review includes a literature search on recently published clinical and laboratory studies (1990-2016) investigating bed bugs as potential vectors of infectious disease, and reports the significant findings and limitations of the reviewed studies. To date, no published study has demonstrated a causal relationship between bed bugs and infectious disease transmission in humans. Also, we present and propose to expand on previous hypotheses as to why bed bugs do not transmit human pathogens. Bed bugs may contain "neutralizing factors" that attenuate pathogen virulence and, thereby, decrease the ability of bed bugs to transmit infectious disease.

Bed bugs can cause severe anaemia in adults.

A 60-year-old woman and her 67-year-old male partner, admitted for pneumonia and non-ST elevation myocardial infarction, respectively, had severe anaemia (Hb 5.3 and 5.2 g/dL, respectively), as a result from massive infestation with Cimex lectularius. After two erythrocyte transfusions and thorough decontamination, their clinical course was unremarkable.

[Ectoparasites. Part 2: Bed bugs, Demodex, sand fleas and cutaneous larva migrans]. / Ektoparasitosen. Teil 2: Bettwanzen, Haarbalgmilben, Sandfloh und Larva migrans cutanea.

Ectoparasites or epidermal parasites include a very heterogenous group of infections of the outer layers of the skin. Worldwide the most common are scabies, lice, tungiasis, and hookworm-induced cutaneous larva migrans. In recent years, bed bug infestations in hotels or vacation homes seem to have become more frequent. Demodex folliculorum and Demodex brevis are found in the facial and scalp hair follicles in 95% of individuals. Classic Demodex folliculitis is often overlooked in differential diagnostic considerations. This inflammatory sebaceous gland disease as well as Demodex blepharitis both provide a diagnostic and therapeutic challenge. Permethrin can be used topically against demodicosis. Vacationers who go barefoot on beaches in tropical Africa, South America and subtropical Asia risk infestations from female sand fleas. The lesions can be curetted or removed with a punch biopsy, then treated with antiseptics or even systemic antibiotics if a secondary infection develops. Cutaneous larva migrans is one of the most common imported ectoparasite infections from the tropics. Topical treatment measures include thiabendazole or cryotherapy. If the infestation is severe, systemic antihelminthics or ivermectin can be employed.

La chinche de cama, ¿un ectoparásito emergente? / No disponible

Fundamentos: La chinche de cama, Cimex lectularius, ectoparásito temporal humano, ha pasado desapercibido a lo largo de las últimas décadas. Sin embargo, su reciente hallazgo en viviendas urbanas hace preverla emergencia de este insecto hematófago, potencial vector de patógenos microbiológicos y parasitarios. Material y métodos: Se reporta un caso de presencia, durante el verano de 2004, de chinches de cama en cuatro dependencias de una vivienda del casco antiguo de la ciudad de Valencia. Cinco de los 8 inquilinosse vieron afectados por picaduras que respondieron a las producidas por chinches de cama. Resultados: Los insectos fueron identificados como pertenecientes a la especie C. lectularius. El tratamiento continuado con insecticidas durante 2 meses y la aplicación de otras medidas profilácticas individuales en la vivienda conllevó la desaparición de los ectoparásitos. Conclusiones: El origen de las chinches pudo ser probablemente la introducción de dos camastros de madera y espuma, por tratarse de la forma más habitual de traslado de estos insectos y por su coincidencia temporal con su detección y la aparición de las picaduras. La inspección minuciosa de enseres de dudosa procedencia antes de su introducción en una vivienda, así como la concienciación de la existencia y el diagnóstico de las picaduras de las chinches, se muestran como las principales medidas profilácticas a seguir, sobre todo en aquellos casos en que la posibilidad de pulgas y/o mosquitos haya quedado descartada como causa aparente (AU)

Purpose: The bed bug, Cimex lectularius, a non permanent human parasite seemed to have disappeared over the last decades. However, recent findings in urban dwellings make it possible to foresee the emergence of this hematofagous insect, a potential vector of microbiological and parasitological pathogens. Material and methods: A case of bed bug presence was reported in the summer of 2004 in four rooms of a flat in the old town in the city of Valencia. Five of the eight tenants were affected by bed bug bites. Results: The insects belong to the species of C. lectularius. The insecticide treatment lasted for two months and the employment of further precautious measures in the flat led to the disappearance of this ectoparasite. Conclusions: The introduction of two wooden structures and foam mattresses of dubious origin might have been the way in which the bed bugs entered the flat - the most probable manner of moving these particular insects, which is reinforced by the temporal coincidence of their appearance and the detection of their bites. The thorough inspection of such “dodgy” belongings before moving them into a house or flat together with the awareness of the bugs’ existence and the diagnosis of their bites, ought to be the main preventive measures to be followed especially in cases which the existence of flees and/or mosquitoes can be discarded as the possible cause (AU)

Enfermedades cutáneas producidas por algunos artrópodos en Chile / Cutaneous diseases caused by some arthropods in Chile

Existen muchos artrópodos que afectan al hombre y a animales. Algunos artrópodos sólo producen manifestaciones cutáneas o sistémicas, otros son vectores de diversas enfermedades. Las picaduras y mordeduras de artrópodos son un motivo de consulta muy frecuente en la práctica dermatológica diaria, la mayoría de diagnóstico y tratamiento fácil, sin complicaciones. A veces, sin embargo, las manifestaciones puden ser tan greves que producen la muerte. En ocaciones, por ejemplo, en pacientes que han viajado al extranjero, el diagnóstico de las lesiones puede ser difícil, y es necesario profundizar en los diagnósticos diferenciales. En este artículo revisamos las patologías cutáneas más frecuentes producidas por distintos artrópodos de las clases Insecta y Aracnida, tales como abejas, pulgas, moscas, chinches, vinchucas, arañas y escorpiones. Se describen con detalle las distintas manifestaciones cutáneas y sistémicas y se entregan algunos elementos teóricos en el tratamiento de éstas

Induction of skin papillomas in the rabbit, Oryctologus cuniculus, by bites of a blood-sucking insect, Cimex lectularius, irradiated by gamma rays.

Bed bugs, Cimex lectularius, irradiated with gamma rays were allowed to suck blood from shaved areas of the skin of rabbits, Oryctolagus cuniculus, 2 times/week for 5 months and then once weekly for another 5 months. This significantly induced the formation of skin papillomas and sweat gland hyperplasia in five out of nine experimental animals. It is speculated that the saliva of the irradiated bugs was activated by gamma rays and was responsible for the induction of skin papillomas. Because bed bugs play a significant role in the transmission of virus, it is also speculated that there is a virus in the saliva of bugs; this virus may be activated by gamma radiation and causes the development of papillomas in the skin.