Rash, Fever, & Headache
Rickettsia species:
- Intracellular rods responsible for a range of illnesses.
- Primarily target the lining of small vessels.
Pathologies:
- Rocky Mountain Spotted Fever
– Bacteria are transmitted by hard ticks.
– Infection produces a
rash that begins on the hands and feet, then spreads to the trunk
– Ocular involvement, such as conjunctivitis, is common.
– Without treatment, widespread vascular damage can lead to organ failure and death.
– Bacteria that cause rickettsialpox are transmitted by mites.
– Infection is characterized by an
eschar, which is an area of redness with a blackish scab, at the site of the mite bite, and a
vesiculopapular rash. The rash somewhat resembles the rash of chicken pox, which is why this illness is called "rickettsialpox".
– Infection is usually mild and self-limiting.
– Bacteria are transmitted via the human body louse.
– Infection produces a
pinkish macular rash that begin on the trunk and spreads to the extremities, and that the palms and soles are spared.
Notice that this rash pattern is exactly the
opposite that of Rocky Mountain Spotted Fever, which begins on the hands and feet and spreads to the trunk.
– Widespread vascular damage can lead to death.
- Brill-Zinsser disease occurs when latent infection re-emerges; it is typically less severe than the initial infection, and rash may be absent.
- Endemic typhus, aka, Murine typhus
– Bacteria are transmitted by fleas that parasitize small mammals, including cats.
– Infection is similar to epidemic typhus, though usually milder.
