rickettsíum

Rickettsia is a genus of bacteria that are obligate intracellular parasites. This means they can only live and reproduce inside the cells of a host organism. Rickettsia are Gram-negative bacteria, meaning they have a specific cell wall structure that stains pink with the Gram stain. They are typically rod-shaped or pleomorphic, meaning they can vary in shape.

These bacteria are primarily transmitted to humans and other animals through arthropod vectors, such as ticks, fleas, mites, and lice. When an infected vector bites a host, it can transmit the Rickettsia bacteria into the bloodstream. Once inside the host, Rickettsia invade various host cells, including endothelial cells (which line blood vessels), macrophages, and other cell types, depending on the specific species.

Rickettsia are responsible for a group of diseases known as rickettsial diseases. The most well-known of these is Rocky Mountain spotted fever, caused by Rickettsia rickettsii and transmitted by ticks. Other important rickettsial diseases include typhus (epidemic typhus caused by Rickettsia prowazekii, transmitted by lice, and murine typhus caused by Rickettsia typhi, transmitted by fleas) and ehrlichiosis, caused by Rickettsia species like Ehrlichia chaffeensis.

Symptoms of rickettsial infections vary but often include fever, headache, rash, and muscle pain. Diagnosis is typically made through serological tests that detect antibodies against the bacteria. Treatment usually involves antibiotics, with doxycycline being a commonly prescribed drug. Prompt treatment is important as some rickettsial diseases can be severe if left untreated.