The common bed bug is a human parasite. Unlike lice,bedbugs are only on their human host to feed,then move off to hide, rest and lay eggs. some people bitten by bed bugs may experience itching and swelling at the site of the bite but others may not have any reaction at all bed bugs have not been shown to transmit disease to humans. Adult bed bugs maybe 1/5 inch long their body is flat which allows them to crawl into narrow cracks. They do not have wings. They can be reddish brown but become a "blood red" after feeding. An adult looks elongated after feeding. Nymphs may look like sesame seeds before feeding and animated drops of blood afterword.
Adult fleas are small (1/16 to 1/8 inch long), wingless, brown to black, bloodsucking insects that are flattened from side to side. Their shape allows them to move between the hairs of an animals coat. While they cannot fly, they can jump as far as six inches. Over 95% of the fleas found on cats and dogs and in dwellings are cat fleas. Fleas will readily bite people but, they will not be able to reproduce well unless they feed on host animals(e.g., dogs, cats). Young children who crawl or spend a lot of time on the floor may get bitten around the ankles. Fleas may bite some people in a home and not others