Blakely, B. N., S. F. Hanson, and A. Romero. 2018. Survival and transstadial persistence of Trypanosoma cruzi in the bed bug (Hemiptera: Cimicidae). Journal of Medical Entomology. 55: 742-746. doi: 10.1093/jme/tjx252
“Bed bug populations are increasing around the world at an alarming rate and have become a major public health concern. The appearance of bed bug populations in areas where Chagas disease is endemic raises questions about the role of these insects in the transmission of Trypanosoma cruzi, the etiological agent of the disease. In a series of laboratory evaluations, bed bug adults and nymphs were experimentally fed with T. cruzi-infected blood to assess the ability of T. cruzi to survive inside the bed bug and throughout the insect’s molting process. Live T. cruzi were observed in gut contents of experimentally infected bed bug adults via light microscopy and the identity of the parasite was confirmed via polymerase chain reaction analysis. T. cruzi persisted at least 97-d postinfection in adult bed bugs. Nymphal stage bed bugs that were infected with T. cruzi maintained the parasite after molting, indicating that transstadial passage of T. cruzi in bed bugs took place. This report provides further evidence of acquisition, maintenance, and for the first time, transstadial persistence of T. cruzi in bed bugs.”
Peterson, J. K., R. Salazar, R. Castillo-Neyra, K. Borrini-Mayori, C. Condori, C. Bartow-McKenney, D. Tracy, C. Naquira, and M. Z. Levy. 2018. Trypanosoma cruzi infection does not decrease survival or reproduction of the common bed bug, Cimex lectularius. American Journal of Tropical Medicine and Hygiene. 98(3): 724-734. doi: 10.4269/ajtmh.17-0593
“Although not presently implicated as a vector of human pathogens, the common bed bug, Cimex lectularius, has been suspected of carrying human pathogens because of its close association with humans and its obligate hematophagy. Recently, we characterized the vectorial competence of C. lectularius for the parasite Trypanosoma cruzi, the causative agent of Chagas disease. We observed that C. lectularius can acquire T. cruzi infection when fed on T. cruzi–carrying mice, and subsequently transmit T. cruzi to uninfected mice. This led us to ask why has C. lectularius not been implicated in the transmission of T. cruzi outside of the laboratory? We hypothesized that T. cruzi reduces C. lectularius fitness (i.e., survival and/or reproduction) as an explanation for why C. lectularius does not to transmit T. cruzi in natural settings. We tested this hypothesis by comparing the survival and reproduction of uninfected and T. cruzi–infected C. lectularius. We observed that T. cruzi had a variable effect on C. lectularius survival and reproduction. There were negligible differences between treatments in juveniles. Infected adult females tended to live longer and produce more eggs. However, no effect was consistent, and infected bugs showed more variation in survival and reproduction metrics than control bugs. We did not observe any negative effects of T. cruzi infection on C. lectularius survival or reproduction, suggesting that decreased fitness in T. cruzi–infected C. lectularius is not why bed bugs have not been observed to transmit T. cruzi in natural settings.”
Houldsworth, A. 2016. Exploring the possibility of arthropod transmission of HCV. Journal of Medical Virology. 89(2): 187-194. doi: 10.1002/jmv.24638
“Hepatitis C virus (HCV) is a major cause of chronic hepatitis, cirrhosis, and liver cancer occurring in up to 3% of the world’s population. Parenteral exposure to HCV is the major mode of transmission of infection. Once established, infection will persist in up to 85% of individuals with only a minority of patients clearing viremia. Egypt has possibly the highest HCV prevalence in the world where 10–20% of the general population are infected with HCV. Endemic HCV appears to be concentrated in the tropics and sub-tropics where there are higher biting rates from insects. The question as to whether a bridge vector transmission is possible, via arthropods, both between humans and/or from an animal reservoir to humans is explored. Mechanical transmission, as opposed to biological transmission, is considered. Mechanical transmission can be an efficient way of transmitting an infection, as effective as biological transmission. Probability of transmission can increase as to the immediate circumstances and conditions at the time. Several factors may enhance mechanical transmission, including high levels of microbes in the vector, frequent biting, the close proximity, and contact between vectors and recipients as well as high density of insects. HCV has been isolated from bodies or heads of mosquitoes collected from the houses of HCV-infected individuals. The possibility of enzootic cycles of HCV tangential transmission via bridging vectors, such as, arthropods needs to be further investigated and possible animal reservoirs, including domestic rural epizootic cycles for HCV infection, requires further research with particular initial emphasis on equine infections.”
Lai, O., D. Ho, S. Glick, and J. Jagdeo. 2016. Bed bugs and possible transmission of human pathogens: a systematic review. Archives of Dermatological Research. 308: 531–538. doi: 10.1007/s00403-016-1661-8
“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.”
Leulmi, H., et al. 2015. Competence of Cimex lectularius bed bugs for the transmission of Bartonella quintana, the agent of trench fever. PLoS Neglected Tropical Diseases. 9(5): e0003789. doi:10.1371/journal.pntd.0003789
“Bartonella quintana, the etiologic agent of trench fever and other human diseases, is transmitted by the feces of body lice. Recently, this bacterium has been detected in other arthropod families such as bed bugs, which begs the question of their involvement in B. quintana transmission. Although several infectious pathogens have been reported and are suggested to be transmitted by bed bugs, the evidence regarding their competence as vectors is unclear.”
Barbarin, A. M., B. Hu, I. Nachamkin, and M. Z. Levy. 2014. Colonization of Cimex lectularius with methicillin-resistant Staphylococcus aureus. Environmental Microbiology. 16: 1222–1224. doi: 10.1111/1462-2920.12384
Researchers investigated the potential for bed bugs to transmit methicillin-resistant Staphylococcus aureus (MRSA) to humans. Results indicated that the bed bug midgut was capable of maintaining the bacteria for up to 9 days, but the bacteria did not replicate within that environment. They concluded that bed bugs are unlikely to transmit MRSA to humans.
Saenz, V. L., R. G. Maggi, E. B. Breitschwerdt, J. Kim, E. L. Vargo, and C. Schal. 2013. Survey of Bartonella spp. in U.S. bed bugs detects Burkholderia multivorans but not Bartonella. PLoS One. 8: e73661. doi: 10.1371/journal.pone.0073661
“Bed bugs (Cimex lectularius L.) have resurged in the United States and globally. Bed bugs are hematophagous ectoparasites of humans and other animals, including domestic pets, chickens, and bats, and their blood feeding habits contribute to their potential as disease vectors. Several species of Bartonella are re-emergent bacterial pathogens that also affect humans, domestic pets, bats and a number of other wildlife species. Because reports of both bed bugs and Bartonella have been increasing in the U.S., and because their host ranges can overlap, we investigated whether the resurgences of these medically important pathogens and their potential vector might be linked, by screening for Bartonella spp. in bed bugs collected from geographic areas where these pathogens are prevalent and from bed bugs that have been in culture in the laboratory for several years. We screened a total of 331 bed bugs: 316 bed bugs from 36 unique collections in 29 geographic locations in 13 states, 10 bed bugs from two colonies maintained in the laboratory for 3 yr, and 5 bed bugs from a colony that has been in culture since before the recent resurgence of bed bugs. Bartonella spp. DNA was screened using a polymerase chain reaction assay targeting the 16S–23S rRNA intergenic transcribed spacer region. Bartonella DNA was not amplified from any bed bug, but five bed bugs from four different apartments of an elderly housing building in North Carolina contained DNA sequences that corresponded to Burkholderia multivorans, an important pathogen in nosocomial infections that was not previously linked to an arthropod vector.”
Goddard, J., A. Varela-Stokes, W. Smith, and K. T. Edwards. 2012. Artificial infection of the bed bug with Rickettsia parkeri. Journal of Medical Entomology. 49(4): 922–926. doi: 10.1603/ME11282
“Although a variety of disease agents have been reported from bed bugs, the mechanical and biological disease transmission potential of bed bugs remains unelucidated. In this study we assayed survivability of the mildly pathogenic spotted fever group rickettsia, Rickettsia parkeri, in bed bugs after feeding on R. parkeri-infected chicken blood. Two groups of 15 adult bed bugs each were fed on infected or noninfected blood, and two groups of fourth-instar bed bugs also were fed on either infected or noninfected blood. One group of 15 adult bed bugs received no bloodmeal and was included as an additional control. Two weeks postfeeding, two pools of five live bed bugs from each group were surface sterilized, macerated, and placed in Vero cell cultures in an attempt to grow live organism. The remaining five individual bed bugs from each group were dissected, their salivary glands were removed for immunofluorescence assay (IFA) staining, and the remaining body parts were processed for polymerase chain reaction (PCR) analysis. Results indicated that no immature (now molted to fifth instar) bed bugs were positive for R. parkeri by IFA or PCR, indicating that organisms did not survive the molting process. After 4 wk of cell culture, no organisms were seen in cultures from any of the treatment or control groups, nor were any cultures PCR positive. However, two of the adult bed bugs were IFA positive for rickettsia-like organisms, and these two specimens were also PCR positive using R. parkeri-specific primers. These IFA and PCR results indicate that remnants of Rickettsia parkeri (possibly whole organisms) survived in the bugs for 2 wk, but the viability of the organisms in these two specimens could not be determined.”
Delaunay, P., V. Blanc, P. Del Giudice, A. Levy-Bencheton, O. Chosidow, P. Marty, and P. Brouqui. 2011. Bedbugs and infectious diseases. Clinical Infectious Diseases. 52: 200–210. doi: 10.1093/cid/ciq102
“Bedbugs are brown and flat hematophagous insects. The 2 cosmopolite species, Cimex lectularius and Cimex hemipterus, feed on humans and/or domestic animals, and recent outbreaks have been reported in occidental countries. Site assessment for bedbug eradication is complex but can be assured, despite emerging insecticide resistance, by hiring a pest-control manager. The common dermatological presentation of bites is an itchy maculopapular wheal. Urticarial reactions and anaphylaxis can also occur. Bedbugs are suspected of transmitting infectious agents, but no report has yet demonstrated that they are infectious disease vectors. We describe 45 candidate pathogens potentially transmitted by bedbugs, according to their vectorial capacity, in the wild, and vectorial competence, in the laboratory. Because of increasing demands for information about effective control tactics and public health risks of bedbugs, continued research is needed to identify new pathogens in wild Cimex species (spp) and insecticide resistance.”
Lowe, C. F., and M. G. Romney. 2011. Bedbugs as vectors for drug-resistant bacteria. Emerging Infectious Diseases. 17: 1132–1134. doi: 10.3201/eid1706.101978
Letter to the editor describing how methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE) were isolated from bedbugs that were found on patients. The prevalence of bedbugs and infections with these two bacteria in humans in Vancouver, British Columbia are discussed. The authors conclude that “bedbugs carrying MRSA and/or VRE may have the potential to act as vectors for transmission.”
Richard, S., P. Seng, P. Parola, D. Raoult, B. Davoust, and P. Brouqui. 2009. Detection of a new bacterium related to “Candidatus Midichloria mitochondrii” in bed bugs. European Society of Clinical Microbiology and Infectious Diseases. 15: 84–85. doi: 10.1111/j.1469-0691.2008.02244.x
Molecular techniques were used to identify bacteria from bed bugs collected from bunks on six French warships. Bed bug samples stored in ethanol were subjected to PCR. Wolbachia spp., a common endosymbiont, and Candidatus Midichloria mitochondrii, recently identified in ticks, were isolated and identified.
Werner, B. G., S. Diallo, W. Wills, M. Pourtaghva, and B. S. Blumberg. 1977. Hepatitis-B virus in bedbugs (Cimex hemipterus) from Senegal. The Lancet. 310: 217–219. doi: 10.1016/S0140-6736(77)92834-3
Tropical bed bugs, Cimex hemipterus, collected from village huts in Senegal, West Africa, were sampled for the presence of hepatitis-B surface antigens. Their data represented the highest field infection-rates of hepatitis B virus reported in any insect species. They concluded that bed bugs need to be considered as a potential vector of hepatitis B virus.
Burton, G. J. 1963. Bedbugs in relation to transmission of human diseases. Public Health Reports. 78: 513–524.
A literature review to evaluate the potential for bed bugs to carry and transmit disease causing organisms. Disease-causing organisms can survive for several days to several weeks inside bed bugs. However, Burton concluded that disease transmission by bed bugs is unlikely in nature.