Presentation on theme: "Black Widow Spider By Kelsey Hamilton. What to look for? The black widow is a medium-sized spider whose body is about a half- inch long. The name is derived."— Presentation transcript:
What to look for? The black widow is a medium-sized spider whose body is about a half- inch long. The name is derived from the mistaken belief that the female invariably kills the male after mating. Although the spider is mostly found in the southern United States, it may be seen throughout the US. Five species are common to the US, with two of them being the most common: The southern black widow has the shiny, black, globular abdomen with the distinctive red hourglass on the underside. The northern black widow has a row of red spots down the middle of the upper surface of its abdomen and two crosswise bars on the undersurface. The markings can also be yellow or white, and the spider itself may be brown or have red legs. Black widow spiders are nocturnal and, thus, are active at night. They prefer dark corners or crevices. They are said to avoid human dwellings, but you can find them in such areas as outhouses and garages. Only the female black widow bites humans, and she bites only when disturbed, especially while protecting her eggs.
Bite Symptoms! The black widow spider produces a protein venom that affects the victim's nervous system. This neurotoxic protein is one of the most potent venoms secreted by an animal. Some people are slightly affected by the venom, but others may have a severe response. The first symptom is acute pain at the site of the bite, although there may only be a minimal local reaction. Symptoms usually start within 20 minutes to one hour after the bite. Local pain may be followed by localized or generalized severe muscle cramps, abdominal pain, weakness, and tremor. Large muscle groups (such as shoulder or back) are often affected, resulting in considerable pain. In severe cases, nausea, vomiting, fainting, dizziness, chest pain, and respiratory difficulties may follow. The severity of the reaction depends on the age and physical condition of the person bitten. Children and the elderly are more seriously affected than young adults. In some cases, abdominal pain may mimic such conditions as appendicitis or gallbladder problems. Chest pain may be mistaken for a heart attack. Blood pressure and heart rate may be elevated. The elevation of blood pressure can lead to one of the most severe complications. People rarely die from a black widow's bite. Life-threatening reactions are generally seen only in small children and the elderly.
Medications! The person bitten by a black widow spider, who has pain severe enough to seek treatment at an Emergency Department, will require narcotic pain relief. Muscle relaxants given by injection may also be of value. Although calcium gluconate given through an IV has long been advocated, it does not seem to produce much relief of symptoms. Symptoms are often not easily relieved, even with narcotics. Some experts recommend that antivenin be used in any severe bite because one vial of the antitoxin produces significant and rapid relief of symptoms. It can even be used if there is delay in reaching the hospital. Yet other sources recommend that antivenin be used only in children, the elderly, and those with severe underlying medical conditions.
Follow Up! Follow-up is always necessary in cases where antivenin is used. Although serum sickness is uncommon with single-vial doses of horse serum, it may occur 7-12 days after exposure and is characterized by skin lesions, fever, pain in the joints, and swollen lymph glands. The symptoms may occur sooner in a sensitized person. The process is self-limited, goes away in 2-3 weeks, and may be treated with antihistamines and steroids.
Prevention! Because black widow spiders bite if they are disturbed, care should be taken in reaching into dark areas. In areas where spider infestations are a problem, the use of a pest control service may also be useful.