Lack of evidence that bedbugs transmit pathogens to humans (2016)

To the Editor: The global population of bedbugs that feed on humans (Cimex lectularius, Cimex hemipterus, and Leptocimex boueti) has undergone a significant resurgence since the late 1990s. Due to increased international travel and pesticide resistance, bedbugs once thought to be native to certain geographic locations have been found in other parts of the world. Bedbugs present a socioeconomic burden because they are costly to eradicate and infestations often recur. According to the US Environmental Protection Agency, bedbugs are "a pest of significant health importance," and upwards of 45 disease pathogens have been reported in bedbugs.1Delaunay P. Blanc V. Del Giudice P. et al.Bedbugs and infectious diseases.Clin Infect Dis. 2011; 52: 200-210Crossref PubMed Scopus (152) Google Scholar, 2United States Environmental Protection Agency. List of Pests of Significant Public Health Importance. 2015. Available at: http://www2.epa.gov/insect-repellents/list-pests-significant-public-health-importance. Accessed August 16, 2015.Google Scholar It stands to reason to ask if bedbugs might transmit human pathogens. We performed a literature review on August 6, 2015, and searched the computerized medical bibliographic databases PubMed, EMBASE, CINAHL, and Web of Science with the search terms: "bedbug" OR "cimex lectularius." A total of 1790 articles were returned, and 12 articles were suitable for inclusion (clinical and laboratory published studies [1990 to 2015] investigating bedbugs as potential vectors of infectious disease) after screening of titles, abstracts, and/or full-text articles. These articles demonstrated that although bedbugs may carry pathogens such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and hepatitis B virus, and may be competent vectors of Bartonella quintana and Trypanosoma cruzi, there were no confirmed cases of human disease transmission. Previous reports suggest that, although a number of different disease pathogen species have been detected in or on bedbugs, there is a lack of definitive evidence that bedbugs transmit human pathogens.1Delaunay P. Blanc V. Del Giudice P. et al.Bedbugs and infectious diseases.Clin Infect Dis. 2011; 52: 200-210Crossref PubMed Scopus (152) Google Scholar, 3Goddard J. deShazo R. Bed bugs (Cimex lectularius) and clinical consequences of their bites.JAMA. 2009; 301: 1358-1366Crossref PubMed Scopus (253) Google Scholar An important challenge for scientists is to determine the reason for this interesting finding. One hypothesis relates to the fact that bedbugs are the only hematophagous arthropod that both feeds on humans and mates by traumatic insemination. Traumatic insemination results in the repeated introduction of pathogens and repeated immune stimulation in the female bedbug, and may thereby select for higher levels of immunity in bedbugs. As a result, the survival and viability of pathogens maintained within bedbugs may be affected.1Delaunay P. Blanc V. Del Giudice P. et al.Bedbugs and infectious diseases.Clin Infect Dis. 2011; 52: 200-210Crossref PubMed Scopus (152) Google Scholar Another hypothesis is that bedbug saliva has been reported to contain lysozymes and other peptides that may have antimicrobial activities.4Doggett S.L. Dwyer D.E. Penas P.F. Russell R.C. Bed bugs: clinical relevance and control options.Clin Microbiol Rev. 2012; 25: 164-192Crossref PubMed Scopus (211) Google Scholar, 5Francischetti I.M. Calvo E. Andersen J.F. et al.Insight into the sialome of the bed bug, cimex lectularius.J Proteome Res. 2010; 9: 3820-3831Crossref Scopus (52) Google Scholar Future research related to these or other hypotheses might lead to greater scientific understanding of how to limit pathogen transmission in humans, and be of significant benefit for patients and global health by preventing human transmission of a variety of infectious diseases.