Rickettsiae are a type of bacteria that can live only inside the cells of other organisms.
Spotted fevers include the following:
Like Rocky Mountain spotted fever, other spotted fevers may occur in the United States and other parts of the world (see table Some Rickettsial and Related Infections). These infections occur mainly in the spring and summer, when adult ticks are active and people are likely to be in tick-infested areas. In warmer climates, the disease may occur throughout the year. Mediterranean spotted fever can occur year-round in the Mediterranean region because it is transmitted by the brown dog tick and thus may be acquired indoors.
Symptoms of these spotted fevers are similar and usually milder than those of Rocky Mountain spotted fever.
About 5 to 7 days after a bite, a fever, fatigue, muscle aches, and headache develop. The eyes are red, and people feel generally unwell. A small buttonlike sore covered by a black scab (eschar) develops at the site of the bite. Usually, nearby lymph nodes are swollen. About 4 days after the fever starts, a red rash appears on the forearms and spreads to most of the body, including the palms and soles. Fever typically lasts over a week.
When appropriately treated, these infections rarely cause serious problems or death. Problems are more likely to occur in older people and in people who already very ill.
Symptoms suggest the diagnosis of a spotted fever.
To confirm the diagnosis, doctors may do an immunofluorescence assay, which uses a sample taken from the rash (biopsy). Or they may use the polymerase chain reaction (PCR) technique to enable them to detect the bacteria more rapidly.
Doctors may do blood tests that detect antibodies to the bacteria. However, doing the test only once is not enough. The test must be repeated 1 to 3 weeks later to check for an increase in the antibody level. Thus, antibody tests do not help doctors diagnose the infection immediately after someone becomes ill but can help confirm the diagnosis later.
Doctors immediately prescribe an antibiotic, usually doxycycline, if they suspect a spotted fever based on symptoms and the potential for exposure to infected ticks—even if laboratory test results are not yet available. The antibiotic is given for 5 days.
To prevent these infections, people should take measures to prevent tick bites.
Preventing tick access to skin includes
DEET should be used cautiously in very young children because toxic reactions have been reported. Permethrin on clothing effectively kills ticks. Frequent searches for ticks, particularly in hairy areas and on children, are essential in areas where infections transmitted by ticks are common.
Engorged ticks should be removed with care and not crushed between the fingers because crushing the tick may result in disease transmission. The tick’s body should not be grasped or squeezed. Gradual traction on the head with a small forceps dislodges the tick. The point of attachment should be swabbed with alcohol. Petroleum jelly, lit matches, and other irritants are not effective ways to remove ticks and should not be used.
No practical means are available to rid entire areas of ticks. However, the number of ticks may be reduced in areas where it is common by making the environment less appealing to the animals that carry the ticks. For example, people can make areas less appealing to mice by removing wood piles and leaf litter and clearing tall grasses and brush around homes, especially play areas. Mice can hide and nest in such places.