Disease Transmission: The possibility of transmission of human disease agents by bed bugs is controversial. Since the insects repeatedly suck blood from humans and live a relatively long time, conceivably they might ingest a pathogen and later transmit it. It has been reported that bed bugs have been suspected in the transmission of 41 human diseases; however, finding a blood-sucking insect infected with a pathogen does not mean that it is a competent vector of that agent, or even a vector at all.

There have been studies of possible HIV transmission by bed bugs. Webb and colleagues found that HIV could be detected in bed bugs up to 8 days after exposure to highly concentrated virus in blood meals, but no viral replication was observed, nor was any virus detected in bed bug feces. In addition, by using an artificial system of feeding bed bugs through membranes, the authors could not demonstrate mechanical transmission of HIV.

Perhaps the best candidate for transmission by bed bugs is hepatitis B virus (HBV). Pools (groups) of bed bugs collected from huts in northern Transvaal, South Africa–an area with high rates of human HBV sero positivity–tested positive for hepatitis B surface antigen (HBsAG). In addition, HBsAG has been shown to persist in bed bugs for at least 7.5 weeks after experimental feeding. However, that same study found no biologic multiplication of HBV in bed bugs. Another study suggested that bed bug feces might be considered a source of mechanical transmission of HBV infection under some circumstances.  However, finding surface antigen in feces is no indication of viable virus.

Whether HBV infectivity survives the bed bug digestive process is unknown. A transmission experiment with chimpanzees helped resolve this issue, although the sample size was small (3 animals). In that study, bed bugs were fed HBV-infected blood through a membrane. Ten to 13 days later, sub-samples of the bugs were tested for infectivity; 53% to 83% were found to be infected. Then, approximately 200 of the infected bugs took meals from the 3 chimpanzees. No infections or seroconversions resulted. To confirm infectivity of the inoculum, the researchers then injected the same 3 animals with a portion of the original blood used to infect the bed bugs. HBV infections followed quickly in all 3 chimpanzees.

Whether or not bed bugs transmit human disease agents remains a point of contention. Attorneys representing plaintiffs bitten by the bugs in hotel rooms often firmly state that the risk is real and warrants compensation. However, until further evidence proves otherwise, I think the best summary of current data goes something like this: "Even though bed bugs have been found naturally infected with many disease agents, they have never been proved to transmit even one."