Typhus is a disease caused by an infection with the Rickettsia bacteria. Fleas, mites (chiggers), lice, or ticks transmit it when they bite you. Fleas, mites, lice, and ticks are types of invertebrate animals known as arthropods. When infected arthropods bite someone, they may leave the bacteria that cause typhus behind. Scratching the bite opens the skin and allows the bacteria to enter the bloodstream. Once in the bloodstream, the bacteria reproduce and grow.
There are three different types of typhus:
- epidemic (or louse-borne) typhus
- endemic typhus
- scrub typhus
The type of typhus you are infected with depends on what bit you. Arthropods are typically carriers of one typhus strain unique to their species.
Typhus outbreaks usually only occur in developing countries or in regions of poverty, poor sanitation, and close human contact. Typhus is generally not a problem in the United States, but you may become infected while traveling abroad.
Untreated typhus can lead to serious complications and it’s potentially fatal. It’s important to see your doctor if you suspect that you may have typhus.
Typhus is not transmitted from person to person like a cold or the flu. There are three different types of typhus and each type is caused by a different type of bacterium and transmitted by a different type of arthropod.
This type is caused by Rickettsia prowazekii and carried by the body louse. It can be found around the world, including in the United States, but is typically found in areas of high population and poor sanitation, where conditions promote lice infestation.
Formerly known as murine typhus, this type is caused by Rickettsia typhi and is carried by the rat or cat flea. Endemic typhus can be found worldwide. It may be found among people in close contact with rats or areas where rats live. It isn’t commonly found in the United States, but cases have been reported in some areas, primarily Texas and southern California.
This type is caused by Orientia tsutsugamushi and carried by mites. This type of typhus is more commonly found in Asia, Australia, Papua New Guinea, and the Pacific Islands. It is also called tsutsugamushi disease.
The louse, flea, tick, or mite becomes infected with the bacteria when they feed on the blood of an infected person or an infected rodent (in the case of endemic typhus). If you come in contact with these infected arthropods (for example, by sleeping on bed sheets infested with lice), their feces may be deposited on your skin when the louse, flea, tick, or mite feeds on your blood. If you scratch the bite, the bacteria can enter your bloodstream through the tiny wound on your skin.
Symptoms vary slightly by the type of typhus, but there are symptoms that are associated with all three types of typhus, such as:
Symptoms of epidemic typhus usually appear suddenly and include:
- severe headache
- high fever (above 104 degrees Fahrenheit)
- rash that begins on the back or chest and spreads
- stupor and seeming out of touch with reality
- low blood pressure (hypotension)
- eye sensitivity to bright lights
- severe muscle pain
The symptoms of endemic typhus last for 10 to 12 days and are very similar to the symptoms of epidemic typhus but are usually less severe. They include:
- dry cough
- nausea and vomiting
Symptoms seen in people with scrub typhus include:
- swollen lymph nodes
- red lesion or sore on the skin at the site of the bite
The incubation period for the disease is 10 to 14 days, on average. This means that symptoms won’t usually appear for 10 to 14 days after you are bitten. Travelers who get typhus while traveling abroad may not experience symptoms until they are back home. This is why it is important to tell your doctor about any recent trips if you have any of the above symptoms.
If you suspect that you have typhus, your doctor will ask about your symptoms and your medical history. To help with the diagnosis, tell your doctor if you:
- are living in a crowded environment
- know of a typhus outbreak in your community
- have traveled abroad recently
Diagnosis is difficult because symptoms are common to other diseases, including:
- dengue (breakbone fever)
- malaria (infectious disease spread by mosquitos)
- brucellosis (infectious disease caused by the brucella bacteria)
Diagnostic tests for the presence of typhus include:
- skin biopsy (sample of the skin from your rash will be tested in a lab)
- Western blot (test to identify presence of typhus bacteria)
- immunofluorescence test (using fluorescent dyes to detect typhus in samples of sputum, which is the thick fluid or mucus found in the lungs and the breathing passages)
- blood test (results can indicate the presence of infection)
Antibiotics most commonly used to treat typhus include:
- doxycycline (preferred treatment)
- cholramphenicol (option for those not pregnant or breast-feeding)
- ciprofloxacin (used for those who are unable to take doxycycline)
Some complications of typhus include:
- hepatitis (infection of the liver)
- gastrointestinal hemorrhage (bleeding inside the intestines)
- hypovolaemia (decrease in blood volume)
Early treatment with antibiotics is very effective and relapses aren’t common if you take the full course of antibiotics. Delayed treatment and misdiagnosis can lead to a more severe case of typhus.
Epidemics of typhus are more common in poor, unsanitary, and crowded areas. People who are most at risk of dying are generally those who are unable to afford quick treatments. The overall mortality rate for untreated typhus ranges from 10 to 40 percent, according to the Ohio Department of Health. The highest rates are seen in the older adults and those who are malnourished. Children usually recover from typhus. People with underlying diseases (such as diabetes mellitus, alcoholism, or chronic renal disorders) also have a higher risk of mortality.
Endemic typhus is rarely deadly, even without treatment (less than 4 percent of cases), according to an article in Clinical Infectious Diseases.
During World War II, a vaccine was created to prevent epidemic typhus. However, the shrinking number of cases has stopped the manufacture of the vaccine. The easiest way to prevent typhus is by avoiding the insects that spread it.
Suggestions for prevention include:
- maintaining personal hygiene (helps guard against lice carrying the disease)
- controlling the rodent population (rodents are known to carry arthropods)
- avoiding travel to regions where typhus exposure has occurred, or to countries that are high risk due to lack of sanitation
- chemoprophylaxis with doxycycline (used as a preventive only in those at high risk, such as those on humanitarian campaigns in areas with extreme poverty and little or no sanitation)
Use tick and insect repellant. Perform routine examinations for ticks, and wear protective clothing if you’re traveling near an area where there have been typhus outbreaks.