What Is Typhus?

Typhus is a group of bacterial diseases caused by rickettsia bacteria infection. This zoonotic illness is transferred to humans by an infected animal, and typical carriers of the bacteria include fleas, mites, and lice.

The infection can spread through the entire bloodstream with systemic (whole-body) involvement, including affecting the central nervous system.

Although the disease is more common in underdeveloped areas, it can be found all over the world. It's uncommon in the United States, but there have been documented cases in parts of the US, including California.

Typhus is considered one of the oldest recorded diseases and was found to have plagued certain populations as far back as the 18th century.

The three different types of typhus include:

• Murine typhus, the endemic type, is transmitted through infected fleas.
• Louse typhus is the epidemic type, contracted through body lice.
• Scrub typhus is transmitted from infected mite larvae.

Types of Typhus

Since typhus presents itself differently depending on the cause and type of the infection, let’s take a more in-depth look at the different strains of the bacterial disease and what each does to the human body.

Murine Typhus (Endemic)

Found mostly in tropical and subtropical climates, endemic typhus is spread through fleas found on rodents. The specific bacteria responsible for the infection is called Rickettsia typhi. The bacteria depend entirely on rodents for its complete lifecycle and thus rely heavily on those populations to thrive.

The bacteria live in the gut of the flea and are excreted in flea feces. When the living bacteria in the feces manage to enter the bloodstream of a mammal, infection occurs.

Louse Typhus (Epidemic)

Epidemic typhus is spread through infected body lice populations and can be found worldwide, although it is more common in Asia, parts of Africa, and Mexico. The number of cases is higher in areas where sanitation is low and population numbers are high.

The specific bacteria that causes this type of typhus is called the Rickettsia prowazekii. It is generally transmitted to lice when they feed on infected hosts.

Cases in the US have been attributed to infected flying squirrel populations. The bacteria survive in the feces of lice and are spread when fecal matter enters the human bloodstream. But it can also be spread via inhalation.

Scrub Typhus (Bush Typhus)

Bush typhus is found in rural areas of northern Australia, Southeast Asia, India, Indonesia, Japan, and China. This type of infection is caused by the Orientia tsutsugamushi bacteria by chiggers or larvae mites.

Scrub typhus can be contracted through both direct feeding and through the fecal intrusion into the bloodstream. Also known as tsutsugamushi disease, this infection can be severe and potentially fatal.

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Typhus Symptoms

Depending on the type of bacteria driving the infection, the symptoms of typhus may vary. The disease course can range from mild to severe, and disease severity can be impacted by factors such as whether treatment was delayed and the infected person's baseline level of health.

Scrub Typhus

Symptoms of scrub typhus include:

• Headaches
• Fever
• Cough
• Nausea and vomiting
• Diarrhea
• Chills
• Body and muscle aches
• A scab at the site of the bite
• Inflammation of lymph nodes
• Skin rash

In more severe cases of scrub typhus, neurological symptoms can appear and include:

• Mental and cognitive changes
• Infection of the brain and thin layers of tissue that cover the brain
• Inflammation of the cerebellum
• Loss of function of cranial nerves
• Inflammation of the spinal cord
• Guillain-Barre syndrome (inflammation of the peripheral nervous system)
• Coma

Louse Typhus

Symptoms of louse typhus include:

• Chills
• Muscle aches
• Cough
• Fatigue
• Headaches
• High fever
• Joint pain
• Abdominal tenderness
• Skin rash that spreads from the back to the rest of the body
• Vomiting
• Sensitivity to light

More serious symptoms can occur in severe cases of the infection including:

• Mental confusion
• Rapid breathing
• Kidney failure
• Brain inflammation that could lead to death

Murine Typhus

Murine typhus symptoms are usually mild, and some people who contract the illness can recover without any treatment at all.

Symptoms include:

• Body aches and pain
• Cough
• Fever and chills
• Gastrointestinal symptoms such as nausea, loss of appetite, stomach pain, and vomiting
• Rash

In very rare cases, when the bacteria invade organs such as the heart, brain, kidney, liver, or lungs, it can leave lasting damage. The infection has been known to lead to acute respiratory distress syndrome, a serious lung condition that can lead to oxygen deficiency, and possibly death.

Other severe complications that can occur in a case of murine typhus include:

• Inflammation of membranes surrounding the brain
• Dangerous drops in blood pressure
• Gall bladder inflammation
• Inflammation of the pancreas
• Muscle inflammation
• Muscle tissue deterioration 

Diagnosis

The chances that you would contract typhus are quite low, especially if you haven’t recently spent time in a high-risk area. If you have symptoms and have had possible exposure to the bacteria, you may need diagnostic testing.

Tests you might need include:

• Skin biopsy
• Immunofluorescence tests (fluorescent dye is used to highlight specific antigens within the blood)
• Serology tests (specimens such as blood are tested for antibodies)
• Polymerase chain reaction (PCR) assay that tests blood, tissues, or plasma can detect the presence of the pathogen

Treatment

All forms of typhus are treated with antibiotics. For those who get prompt treatment, typhus is generally resolved.

Antibiotics used to treat bacterial infection include:

• Tetracycline
• Doxycycline
• Azithromycin

These antibiotics are used to rid the body of bacteria.

Long-Term Effects of Typhus

When typhus remains untreated, it can lead to long-term health effects. Serious and lasting symptoms that can occur in an untreated typhus infection include:

• Hearing loss
• Secondary bacterial infections
• Seizures
• Neurological decline such as confusion
• Fatigue

Low blood pressure, pneumonia, organ failure, and gangrene are serious complications that can lead to death from typhus.

There have been instances of the illness returning years after the initial infection took place. This condition is known as Brill-Zinsser disease. When a bacteria is able to lay dormant within the body, it can be ‘missed’ by antibiotics only to reactivate later on. In Brill-Zinsser disease, the symptoms are similar but milder than that of a typical case and will require treatment with antibiotics once again.

Prevention

The most important step to avoiding a typhus infection is staying away from rodents and wild animals, even the adorable cuddly ones.

Since the disease is spread through mites, lice, and fleas, keeping your distance from any animal that may be targeted by these carriers is the best bet in avoiding the infection. It's a good idea to keep your house and surroundings less appealing to animals looking for a place to call home.

If you have pets, be sure to keep them away from any other rodents or animals that may spread fleas or mites (no matter how hard they may want to chase that squirrel).

A Word From Verywell

Typhus can make you very sick if you catch the infection. Try to avoid exposure in your day to day life and be sure to practice prevention if you travel to an area of high risk. If you are exposed, be watchful of symptoms and see your healthcare provider promptly if you begin to experience the effects of the infection—treatment can be lifesaving.