: Bed bugs spread disease.

FACT: Bed bugs have been accused of transmitting a number of diseases. So far, no findings have confirmed any transmission of any disease by a bed bug to a human. Theories suggest that bed bugs may pose the threat of anemia, however, especially in cases involving heavy infestations. Read Canadian Medical Journal article

Bed bugs are concerns for psychological problems, however, including: poor steep, stress, anxiety and paranoia.  
Secondary infections can occur from agitating or scratching bed bug bites, however. Source. Every effort should be made to prevent scratching irritated bites. Calamine lotion, ice and antihistamines may help with itching and swelling.

Myth: Bed bugs can spread Chagas disease.

Fact: Common bed bugs (the ones we’re hearing so much about lately) are not known to transmit diseases.

There are worse pests than bed bugs. Common bed bugs are not known to transmit any disease, though they are suspected threats for anemia and a number of psychological conditions. The association of Bed Bugs with Chagas disease comes from a parasitic insect common near the Equator.  The insect is commonly referred to as a Mexican bed bug, kissing bug, assassin bug, or triatomine. They are not closely related to common bed bugs, though they share a common trait; both feed on human blood. Kissing Bug, Conenose Bug, Masked Hunter