Flea-borne (murine) typhus

Flea-borne (murine) typhus is a disease caused by the bacteria Rickettsia typhi. Flea-borne typhus is spread to people through contact with infected fleas, most commonly the Oriental rat flea (Xenopsylla cheopsis) and the cat flea (Ctenocephalides felis). Fleas become infected when they bite infected animals, such as rats, cats, or opossums. Once infected, the flea remains infected for the remainder of its life.

When an infected flea bites a person or animal, the bite breaks the skin, causing a wound. Fleas poop when they feed. This poop (also called flea dirt) contains the bacteria, which can be rubbed into the bite wound or other wounds and cause an infection. People can also breathe in infected flea dirt or rub it into their eyes. These bacteria do not spread from person to person.

Flea-borne typhus occurs in many tropical, subtropical, and temperate climates around the world, including several countries in Southeast Asia, Africa, Central and South America, southern Europe, and the Middle East. In the United States, southern California, Hawaii, and southern Texas report most cases, although cases likely occur in other states. In the few states that report this disease, the number of reported cases has increased significantly during the last decade, suggesting that flea-borne typhus may be considered a re-emerging infectious disease in certain areas of the United States.

Signs and Symptoms

Xenopsylla cheopis, the Oriental rat flea

Symptoms of flea-borne typhus begin within several days and as long as 2 weeks after contact with infected fleas or flea dirt. However, people often do not know they have been bitten by a flea or exposed to flea dirt. Patients, tell your healthcare providers about time spent outdoors or contact with particular animals, especially rats, opossums, or free-roaming cats. Signs and symptoms of flea-borne typhus can include:

• Fever and chills
• Body aches and muscle pain
• Loss of appetite
• Nausea
• Vomiting
• Stomach pain
• Cough
• Rash (typically occurs in about half of patients, and generally begins around day 5 of illness)

Severe illness can occur in some people, but deaths are rare (estimated to be less than 1% of all cases). Almost all cases resolve completely with appropriate antibiotics. Hospitalizations are frequent among people with unrecognized or untreated disease. The disease can cause severe illness can damage one or more organs, including the liver, kidneys, heart, lungs, and brain.

Diagnosis and Testing

• The signs and symptoms of flea-borne typhus in the first week of illness are similar to those of many other diseases. See your healthcare provider if you develop the symptoms listed above, and if appropriate, be sure to mention contact with fleas, domestic rodents (rats and mice), stray animals (such as cats), or wildlife (such as opossums).
• Your healthcare provider may order a blood test to look for the bacteria that cause flea-borne typhus or other diseases, or to measure antibodies indicating recent exposure.
• Laboratory testing and reporting of results can take several weeks, so your healthcare provider should start treatment before results are available.

Treatment

• Flea-borne typhus is treated with the antibiotic doxycycline. Doxycycline can be used in people of all ages, including young children.
• Antibiotics are most effective when given soon after symptoms begin.
• People treated early with doxycycline usually recover quickly.
• There is no evidence that persistent or chronic infections occur.

Prevention

• There is no vaccine to prevent flea-borne typhus.
• Reduce your risk of getting flea-borne typhus by avoiding contact with fleas.
• Keep fleas off your pets. Talk to your veterinarian about flea control products for cats and dogs, such as flea collars, oral medication, or topical flea prevention products. Permethrin should not be used on cats. Animals that are allowed outside are more likely to come in contact with fleas and may bring them inside.
• Keep rodents and wild animals (e.g., opossums) away from your home, workplace, and recreational areas:
  • Store food, including pet food, in tightly sealed containers.
  • Remove brush, rock piles, junk, and clutter outside of your home.
  • Seal up holes in your home where rodents can enter.
  • Tighten lids on compost and trash cans to discourage animal visitors.
  • The CDC’s rodents website offers helpful suggestions on rodent control during and after a rodent infestation.
• Protect yourself from flea bites.
  • Do not feed or pet wild or stray animals.
  • Always wear gloves if you are handling sick or dead animals.
  • Use Environmental Protection Agency-registered insect repellents on your skin and clothing when spending time outside. Always follow instructions listed on the product label as some products are for skin and others are for clothing only.