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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.
Keywords: Bed bugs, Public health, Pathogens, Infectious diseaseThe global population of bed bugs (Cimex lectularius and Cimex hemipterus, family Cimicidae) has undergone a significant resurgence since the late 1990s [1, 2, 13, 14, 17, 26, 36, 37, 47]. This is likely due to an increase in global travel, trade, and the number of insecticide-resistant bed bugs [11, 21]. In 2014, the number of international travelers reached 1.1 billion (leisure tourists accounted for 53 %) and is estimated to reach 1.8 billion by 2030 [45]. Travelers are at a particular risk for infestation, as bed bugs have been detected in aircraft, boats, trains, and hotels [12]. The global bed bug population is estimated to be increasing by 100–500 % annually [3]. In one nationwide survey, 99.6 % of United States (U.S.) pest professionals reported that they have treated bed bugs in the past year, and 68 % of U.S. pest professionals reported that bed bugs are the most challenging pest to treat [30].
Bed bugs are a significant socioeconomic burden. Complete eradication of bed bugs is challenging as bed bugs are very mobile and can travel extensively to neighboring units [9]. The estimated cost of disinfecting a house with standard insecticide and replacing infested belongings, such as clothes and bedding, is approximately $2500–$3000 (USD) per infestation [11]. For commercial and industrial workplaces, infestations may cost upwards of millions of dollars [35], and the healthcare industry is no exception. A study reported that 58 % of U.S. pest professionals encountered infestations in nursing homes, 36 % in hospitals, and 33 % in physician offices [30]. Additionally, entire hospital wards have been shut down due to infestations [4, 41].
Published evidence supports that bed bugs are experiencing a global resurgence and that bed bugs once thought to be native to certain geographic locations have been found in other parts of the world [11, 42]. For example, in 2014, C. lectularius was detected for the first time in the Chilean province of Magallanes, which is the southernmost record for this species in South America [16]. Cimex hemipterus, the bed bug indigenous to the tropics and subtropics, has been found in the United Kingdom, and is representative of the global spread of bed bugs [11]. Cimex lectularius and C. hemipterus are two species that primarily feed on humans (in addition to domestic animals) [13, 18], and a global spread of these two bed bug species may translate to widespread infestations and may also act as a route of human pathogen transmission. Recently, the media and the medical community have been concerned about this very possibility, and the amount of media attention focused on bed bugs has increased [11, 13, 39].
Bed bugs are a major concern to public health. According to the U.S. Environmental Protection Agency, bed bugs are “a pest of significant health importance,” and bed bugs have been reported to carry more than 40 microorganisms in the stomach, feces, exoskeletons, and/or saliva [13, 46]. Recent studies reported that bed bugs may act as competent vectors for pathogens, such as Bartonella quintana and Trypanosoma cruzi, the causes of trench fever and Chagas disease, respectively [23, 24, 37]. However, public health reports have thus far failed to produce evidence that major infectious disease outbreaks have been associated with bed bugs. Additionally, other members of the family Cimicidae are competent vectors for arboviruses for birds and, also, likely for wild bats [1, 14]. 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. Also, we present and propose to expand on previous hypotheses as to why bed bugs do not transmit human pathogens.
We employed the following literature review search strategy: on May 6, 2016, we systematically searched the computerized medical bibliographic databases PubMed, EMBASE, CINAHL, and Web of Science with the following search terms: “bed bug” OR “cimex lectularius” OR “cimex lectularis” OR “cimex hemipterus” (see Fig. 1 for schematic of literature search strategy based upon the preferred reporting items for systematic reviews and meta-analyses [PRISMA] guidelines) [29]. The relevant articles that met the following criteria were selected for inclusion: original clinical or laboratory research articles that evaluated vector-borne pathogens with bed bugs or C. lectularius or C. lectularis or C. hemipterus from January 1, 1990 to May 6, 2016. Exclusion criteria included: vector-borne pathogens not related to bed bugs or C. lectularius or C. lectularis or C. hemipterus and non-English articles. Information on study type, bed bug genus/species, pathogen(s), and significant findings of published reports was extracted.