Bedbug - Close-Up

Bed bugs don't carry disease, but their bites can leave a colorless welt along with an itching or burning sensation. (Courtesy of the Centers for Disease Control.)

Black Widow Spider

This is a black widow spider. Note the red "hour glass" on the abdomen. The bite of the black widow produces severe symptoms but is seldom fatal, except in children less than 3 years old and adults over 55 years old. (Courtesy of the Centers for Disease Control.)

Body Louse

This is a magnified view of a body louse. Lice produce itching and a characteristic excoriated skin rash (looks like a scrape). They may also carry relapsing fever, typhus, and trench fever. (Courtesy of the Centers for Disease Control.)

Flea

Different types of fleas prefer specific animals as hosts, but will infest humans if their specific hosts are unavailable. Fleas can carry plague (the Black Death) and murine typhus. They are also thought to be vectors in several other diseases. (Courtesy of the Centers for Disease Control.)

Fly

Flies are thought to carry disease by transporting infectious agents on their feet. They may spread polio, hepatitis A, Entameba histalytica, typhoid, and other diseases. (Courtesy of the Centers for Disease Control.)

Insect, the Basic Features of Adults

This illustration notes the basic characteristics of adult insects in general. (Courtesy of the Centers for Disease Control.)

Kissing Bug

The kissing bug can carry relapsing fever and Chagas' disease (American trypanosomiasis). (Courtesy of the Centers for Disease Control.)

Mite

This is a magnified photograph of a dust mite. Mites are carriers (vectors) of many important diseases including typhus (scrub and murine) and rickettsialpox. (Courtesy of the Centers for Disease Control.)

Mosquito, Adult Feeding on the Skin

There are many different species of mosquito, some of which carry some of the worlds most common and most economically important infectious diseases. Malaria and yellow fever are two of the most important diseases they carry. Others include encephalitis (viral), dengue fever, and leishmaniasis. (Courtesy of the Centers for Disease Control.)

Mosquito, Egg Raft

Mosquitoes of the Culex species lay their eggs in the form of egg rafts that float in still or stagnant water. The mosquito lays the eggs one at a time sticking them together in the shape of a raft. An egg raft can contain from 100 to 400 eggs. The eggs go through larval and pupal stages and feed on micro-organisms before developing into flying mosquitoes. (Courtesy of the Centers for Disease Control.)

Mosquito, Larvae

This picture shows mosquito larvae, most of which will become blood-sucking, disease-carrying mosquitoes. (Courtesy of the Centers for Disease Control.)

Mosquito, Pupa

These are mosquito pupa. This is another stage in the development of the mosquito. (Courtesy of the Centers for Disease Control.)

Wasp

Wasps are not known to carry human diseases, but allergic reactions to their sting can be fatal. (Courtesy of the Centers for Disease Control.)

Insect Stings and Allergy

Allergic reaction to bee stings occurs when a person becomes sensitized to the venom from a previous sting. This reaction is different from the reaction to the poison in the bite of a black widow spider, which injects a potent toxin into the blood. Ordinarily, bee venom is not toxic and will only cause local pain and swelling. The allergic reaction comes when the immune system is oversensitized to the venom and produces antibodies to it. Histamines and other substances are released into the bloodstream, causing blood vessels to dilate and tissues to swell. Severe reactions can lead to anaphylactic shock, a life-threatening series of symptoms including swelling of the throat and difficulty breathing. Persons who develop an allergy to bee stings should carry prescription bee sting kits to counteract the reaction to bee venom.

Brown Recluse Spider

The brown recluse is a poisonous spider most commonly found in midwestern and southern states of the United States. It is about one-half inch overall and has long skinny legs. The brown recluse is brown with a characteristic dark violin-shaped marking on its head. It is most commonly found outside in wood, leaves, or in piles of rocks. If a brown recluse wanders indoors they will go to dark closets, shoes, or attics. The brown recluse is a non-aggressive spider and will only bite when it is disturbed.

Black Widow Spider

The female black widow is easily recognized by her shiny black body and red hourglass marking underneath her round abdomen. Although black widows can be found in nearly every state they are most common in the southern areas of the United States. The black widow makes her home in wood piles, under eaves, and other undisturbed places. The bite of a black widow can be serious and require medical attention. Symptoms include pain radiating from the site of the bite, nausea, overall aching of the body, profuse sweating, and labored breathing.

Stinger Removal

To remove a stinger, scrape the back of a knife or other straight-edged object across the stinger. Do not use tweezers since it may squeeze the venom sac and increase the amount of venom released into the wound. Next wash the site thoroughly with soap and water. Place ice wrapped in a washcloth or other suitable covering on the site of the sting for 10 minutes and then off for 10 minutes. If needed an antihistamine can be applied to help reduce the itching. Over the next several days the stinger site should be watched for signs of infection, such as increased redness, swelling, or pain.

Flea Bite - Close-Up

Fleas are blood-feeding insects. Pain and itching results from an allergic reaction to the materials that the fleas inject into the skin at the time of the bite.

Insect Bite Reaction - Close-Up

This is a 2 to 3 centimeter wide blood-filled (hemorrhagic) blister ( bullae) that has resulted from an insect bite. It is located on the wrist. Bullae formation and tissue necrosis (death) are more common with spider bites, but may also be caused by insect bites.

Insect Bites on the Legs

Insect bites may be grouped, raised (papular), hive-like (urticarial) and have a surrounding halo. Occasionally a central depression, or punctum, can be seen.

Head Louse Emerging from Egg

This is a photograph of Pediculus humanus var. capitis, a head louse, emerging from an egg. Head lice have become an increasing problem in schools and day care centers. Some grade schools have started programs to examine children for head lice.

Head Louse, Male

This is a photograph of a male Pediculus humanus var. capitis, a head louse, as seen from the top. Head lice have become an increasing problem in schools and day care centers. Some grade schools have started programs to examine children for head lice.

Head Louse - Female

This is a photograph of a female Pediculus humanus var. capitis, a head louse, as seen from the top. Head lice have become an increasing problem in schools and day care centers. Some grade schools have started programs to examine children for head lice.

Head Louse Infestation - Scalp

This is a close-up picture of lice egg sacks (nits) in the hair. They cling to individual hair shafts. (Courtesy of the Centers for Disease Control.)

Lice, Body with Stool (Pediculus Humanus)

These lice are Pediculus humanus, or body lice. Other types of lice infest the scalp, head (Pediculus humanus capitis), and the pubic area (Rhthirus pubis). Some body lice may carry diseases such as epidemic typhus, relapsing fever, or trench fever. (Courtesy of the Centers for Disease Control.)

Body Louse, Female and Larvae

This is a magnified view of a female body louse with larvae. Lice cause itching and a characteristic excoriated skin rash (looks like a scrape). They may also transmit diseases, including relapsing fever, typhus, and trench fever. (Courtesy of the Centers for Disease Control.)

Crab Louse, Female

This is a photomicrograph of a female pubic louse. The condition known as "crabs" is so named because of the resemblance of a pubic louse to a crab. The bodies of pubic lice are shorter and rounder than those of head lice. (Courtesy of the Centers for Disease Control.)

Pubic Louse-Male

This is a photomicrograph of a male pubic louse. The condition known as "crabs" is so named because of the resemblance of a pubic louse to a crab. The bodies of pubic lice are shorter and rounder than those of head lice.

Crab Lice

This photograph shows pubic lice clinging to individual hairs (the small, whitish specks). The reddish, crusted areas with scabs (excoriated areas) are caused by scratching. (Courtesy of the Centers for Disease Control.)

Head Louse and Pubic Louse

This picture compares the relative size and shape of the head louse and the pubic louse.

Brown Recluse Spider Bite on the Hand

This lesion was produced by the bite of a brown recluse spider. Brown recluse are one of two spiders in the United States that are considered poisonous (the other is the black widow). However, the Hobo spider can also produce bites that require medical attention.

Insect Bites and Stings

Even though some insect bites or stings can be extremely painful they usually do not require emergency medical care. Although the stung or bitten area should be carefully observed for signs of infection or reaction to venom.