What vector is
responsible for transmitting the bacterium that causes the rash seen in this
picture? Where in the US would you most
likely diagnose a patient with this disease?
Rocky Mountain Spotted Fever is transmitted by the American dog tick, brown dog tick, and Rocky Mountain wood tick. The name comes from the region in which the disease was first found. But the name of the disease is misleading, because Rocky Mountain Spotted Fever occurs primarily along the East Coast of the United States (in the southeastern states of Virginia, North Carolina, and Georgia), where the American dog tick, Dermacentor variabilis, is located. This tickborne disease is caused by the bacterium Rickettsia rickettsii and it can lead to severe or even fatal illness.
This disease is characterized by the acute onset of nonspecific symptoms (e.g., fever, severe headache, myalgias, and prostration). The typical rash, which appears 2 to 6 days later, begins with macules that frequently progress to petechiae that appear first on the hands and feet and then move inward to the trunk. Profound central nervous system changes such as delirium and coma may occur, as well as disseminated intravascular coagulation (DIC), edema, and circulatory collapse. The diagnosis must be made on clinical grounds and therapy started promptly, because the first line treatment doxycycline is most effective if started before the fifth day of symptoms.
Photos courtesy of: Lichtman’s Atlas of Hematology and the Review of Medical Microbiology and Immunology
Explanation courtesy of: the Review of Medical Microbiology and Immunology and the CDC RMSF web entry.
Rocky Mountain Spotted Fever is transmitted by the American dog tick, brown dog tick, and Rocky Mountain wood tick. The name comes from the region in which the disease was first found. But the name of the disease is misleading, because Rocky Mountain Spotted Fever occurs primarily along the East Coast of the United States (in the southeastern states of Virginia, North Carolina, and Georgia), where the American dog tick, Dermacentor variabilis, is located. This tickborne disease is caused by the bacterium Rickettsia rickettsii and it can lead to severe or even fatal illness.
ReplyDeleteThis disease is characterized by the acute onset of nonspecific symptoms (e.g., fever, severe headache, myalgias, and prostration). The typical rash, which appears 2 to 6 days later, begins with macules that frequently progress to petechiae that appear first on the hands and feet and then move inward to the trunk. Profound central nervous system changes such as delirium and coma may occur, as well as disseminated intravascular coagulation (DIC), edema, and circulatory collapse. The diagnosis must be made on clinical grounds and therapy started promptly, because the first line treatment doxycycline is most effective if started before the fifth day of symptoms.
Photos courtesy of: Lichtman’s Atlas of Hematology and the Review of Medical Microbiology and Immunology
Explanation courtesy of: the Review of Medical Microbiology and Immunology and the CDC RMSF web entry.