File:Bed bug, Cimex lectularius.jpg

ID#: 9822

This 2006 photograph depicted an oblique-dorsal view of a bed bug nymph (Cimex lectularius) as it was in the process of ingesting a blood meal from the arm of a “voluntary” human host.

Bed bugs are not vectors in nature of any known human disease. Although some disease organisms have been recovered from bed bugs under laboratory conditions, none have been shown to be transmitted by bed bugs outside of the laboratory.

The common bed bug is found worldwide. Infestations are common in the developing world, occurring in settings of unsanitary living conditions and severe crowding. In North America and Western Europe, bed bug infestations became rare during the second half of the 20th century and have been viewed as a condition that occurs in travelers returning from developing countries. However, anecdotal reports suggest that bed bugs are increasingly common in the United States, Canada, and the United Kingdom.

C. lectularius inject saliva into the blood stream of their host to thin the blood, and to prevent coagulation. It is this saliva that causes the intense itching and welts. The delay in the onset of itching gives the feeding bed bug time to escape into cracks and crevices. In some cases, the itchy bites can develop into painful welts that last several days.