Bed Bugs

Bed bugs have been around for thousands of years. They feed on blood, but are not known to spread any diseases to humans. Some people can be allergic to their bites. Getting rid of a bed bug infestation is not easy.
Bed bugs get their name because they are commonly found in beds but can also be found in other places where humans spend a lot of time: hotels, airplanes, and couches.
Determining the source is very difficult in most cases but once you have them it doesn't matter where they came from, all that matters is getting rid of them.
A likely sign of bed bugs are reddish spots of blood on sheets, mattresses or walls especially where you sleep

You may have bites that appear in a row of 3-4 welts or more
Bed Bug bites may vary between a mild itch to a more severe rash like symptom
Most bed bugs feed on their hosts while they are asleep. The host supplies them with blood in a painless way, never knowing it is happening. While feeding they inject a small amount of saliva into the host's skin. The more they feed on one particular host, say a human, over a period of several weeks, the more sensitized that human becomes to their saliva. Until eventually the host develops a mild to intense allergic response.

People who have become sensitive to bed bug bites - their saliva - have lesions similar to mosquito or flea bites. Most humans will think they have been bitten by some insect, such as a mosquito, and never realize who the true culprit was.