Microbiology

Microbiology Study Guide

disease is transmitted by lice and a major outbreak was witnessed during World War I, where many soldiers were infected while in the trenches. Another form of rickettsial disease is ehrlichiosis, which is caused by the bacterium Ehrlichia canis . Ehrlichiosis does not cause any skin rashes, but the patient may complain of a high fever and severe headache. Similarly, human granulocytic ehrlichiosis is another form of rickettsial disease and is caused by the same bacteria belonging to the species of Ehrlichia . The disease is transmitted by ticks. All these rickettsial diseases can be treated with a drug therapy of antibiotics, including tetracycline. Q Fever The bacterium Coxiella burnetii is responsible for causing Q fever. The disease is transmitted by airborne droplets, unpasteurized milk and dairy products, ticks, and other arthropods. Treatment includes antibiotics, usually tetracycline. Lyme Disease The spirochete bacterium Borrelia burgdorferi causes Lyme disease. The disease is transmitted by ticks belonging to the species of Ixodes. The disease is known as Lyme disease since it originated in Lyme, but later instances of this disease have been observed throughout the United States. The disease is transmitted by tick bites. Symptoms include a bull’s-eye rash on the skin, popularly known as erythema chronicummigrans. When the tick bites the individual, a red rash appears on the affected area and extends over the next few days. After a few days, the rash fades and the spirochete travels to the bloodstream of the infected person. Symptoms at this stage include fever and an irregular beating of the heart. In extreme cases, the person suffers from paralysis of the face and meningitis. The disease is likely to have long-term effects and may include arthritis of the joints. Treatment of Lyme disease is possible with an antibiotic course of penicillin and tetracycline. Toxic Shock Syndrome Toxic shock syndrome is generally caused by the Staphylococcus aureus (staph) bacteria and is sometimes caused by the toxins produced by group A Streptococcus (strep) bacteria. Risk factors for this syndrome are wounds on the skin, skin burn, and surgery. The bacteria enter the body through an opening, like a cut, sore, or wound on the person's body. Toxic shock may also be caused by women using tampons for a long time. The disease is diagnosed by a physical examination and by finding traces of Streptococcus bacteria in urine and blood samples. The physician may also check for traces of the bacterial cells by examining swabs extracted from the vagina, cervix, and throat. Possible treatment for toxic shock syndrome includes an intravenous antibiotic, IV fluids, and gamma gloubin injections. Viral Diseases Yellow Fever Yellow fever is caused by a mosquito bite and belongs to the genus Aedes aegypti . The disease is transmitted when the mosquito injects icosahedral, an RNA particle of the virus, in the human body. Once the mosquito injects this virus, it travels to the bloodstream and lymph nodes and moves to other blood engorged organs, like the liver. Major symptoms include nausea, fever, and jaundice. The

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