Murine typhus

Description, Causes and Risk Factors:

Murine typhus is a bacterial disease caused by Rickettsia typhi or possibly Rickettsia felis. Murine typhus is found Worldwide, chiefly in tropical and coastal areas. In the United States there are about 200 cases of Murine typhus reported every year. Most of the cases occur in Texas, California, and Hawaii. Murine typhus is considered endemic (always present) in small areas of Los Angeles and Orange Counties, but may also occur in other parts of California.

Murine typhus persists at a low level in the United States, where most cases are seen in the South Texas and Southern California. Rat is the main reservoir of R. typhi and rat flea, Xenopsylla cheopis, is the main vector. An important vector in some areas (South Texas and Southern California) is the cat flea, Ctenocephalides felis, and opossums have been implicated as a potential reservoir in these areas. An experimental model of infection of the human louse by R. typhi has demonstrated that this arthropod could occasionally play a role in the epidemiology of Murine typhus.

Infection occurs when flea feces containing the disease agent are scratched into the bite site or other skin opening, are transferred to the eye (conjunctiva), or when dried or crushed feces are inhaled and enter the airway.

The incubation period for Murine typhus is 6 to 14 days.

Preventive measures:

• Control flea infestation.

• Eliminate food sources and other areas that may harbor wild animals.

• Take personal precautions. Limit your exposure by avoiding areas that may be infested with fleas.

Symptoms:

Although most illnesses are mild and undetected, many people infected with Murine typhus experience fever, headache, chills, and muscle aches 6 -14 days after the bite of an infected flea. Some people will also get a rash that begins on the chest and spreads to the sides and back.

Diagnosis:

A complete blood count (CBC) may show a low white blood cell count, anemia, and low platelets. Other blood tests for typhus may show:

High level of typhus antibodies.

• Low level of albumin.

• Low sodium level.

• Mildly high liver enzymes.

Presumptive diagnosis can be confirmed by paraclinic exams, especially Serology. Rash, eschar biopsy can allow detection of Rickettsiae by immunohistochemistry, and culture of R. typhi. R. typhi can also be detected in fleas by culture, PCR, or immunohistochemistry.R. typhi culture is only possible in Specialized laboratory with P3 security level, on cell culture.

Treatment:

Murine typhus is treated with antibiotics. Most people recover in a few days. Some people require hospitalization. Death from typhus is rare, 2 - 4% without treatment. Commonly prescribed antibiotics include doxycycline, tetracycline, chloramphenicol. Tetracycline taken by mouth can permanently stain teeth that are still forming. It is usually not prescribed for children until after all of their permanent teeth have grown in.

NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.