Typhus

• Typhus is a group of diseases that cause fever, headache, and rash.
• Throughout history, typhus has been responsible for millions of deaths.
• Types of typhus include scrub typhus, murine or endemic typhus, and epidemic typhus.
• Bacteria of the Rickettsia family causes typhus, and arthropods (chiggers, lice, mites, or fleas) spread the bacteria to humans.
• Epidemic typhus, spread by lice, causes the most severe symptoms but is rare today.
• Fleas spread murine typhus.
• There are no vaccines available to prevent any of the forms of typhus.
• Treatment with the antibiotic doxycycline usually leads to rapid recovery from typhus.
• Typhus today mostly exists in areas of overcrowding and poor hygiene.

Typhus is the name for a group of potentially deadly but treatable bacterial infectious diseases that spread among humans via lice, chiggers, and fleas. Medical professionals sometimes refer to these conditions as typhus fevers. The typhus fevers include scrub typhus, murine typhus, and epidemic typhus.

• Chiggers (larval mites) spread scrub typhus, and it occurs in Southeast Asia, Indonesia, China, Japan, India, and northern Australia.
• Murine typhus (endemic typhus) is flea-borne typhus and still occurs in some areas of the U.S.
• Epidemic typhus is uncommon today and spreads via body lice.

The earliest historical documentation of typhus may have been by the ancient Greeks. By the Middle Ages, descriptions of typhus can be found in the recorded literature. Typhus epidemics were described throughout Europe for many centuries. The numerous outbreaks occurred due to poor living conditions, where high numbers of rats, mice, and other animals are common. Examples of historical outbreaks include an outbreak among Napoleon's troops retreating from Moscow in 1823, a massive outbreak with over 100,000 deaths in Ireland in the 1830s, and outbreaks in several U.S. cities in the 19th century. Typhus claimed over 3 million lives during and after World War I. Delousing stations reduced the rate of typhus infection and death among military personnel and civilians.

Typhus epidemics were described in German concentration camps during the Holocaust. The diarist Anne Frank died from typhus in the Bergen-Belsen concentration camp at age 15. Eventually, the insecticide DDT was used at the end of World War II to kill body lice, and only a few epidemics have occurred since then. DDT has been banned in the U.S. since 1972 due to toxicity.

The bacteria Orientia tsutsugamushi causes scrub typhus. It spreads by bites of infected chiggers. Most cases of scrub typhus occur in rural areas in Southeast Asia, China, Japan, India, Indonesia, and northern Australia.

The bacteria Rickettsia typhi causes endemic typhus (murine typhus). Murine typhus spreads through contact with infected fleas. Typically, the spread of the infection takes place when infected flea feces are rubbed into cuts or scrapes in the skin. Rats are the main animal host worldwide for fleas infected with the bacteria. The illness is common in tropical and subtropical climates where rats and their fleas live. In the U.S., rat or cat fleas caused uncommon murine typhus outbreaks.

Epidemic typhus is rare today. Rickettsia prowazekii bacteria causes it, and it spreads through infected body lice. This type of typhus caused millions of deaths historically when body lice were more prevalent. It has occurred rarely in the U.S., when people have been exposed to flying squirrels and their nests.

Symptoms of typhus usually begin 5 to 14 days after infection.

The symptoms and signs of typhus can vary among the different types, but all forms typically cause fever, headache, body aches, and rash.

Scrub typhus causes the typical fever, chills, and headache, as well as a rash and a dark, scab-like sot (called an eschar) at the site of the chigger bite. Other signs and symptoms include enlarged lymph nodes, body and muscle aches, and mental changes such as confusion. Coma can result from severe cases.

Symptoms of endemic typhus may include a high fever, headache, malaise, nausea, and vomiting. The rash appears on the chest and abdomen about 4 to 7 days after the initial symptoms develop and sometimes spreads to other areas. Some people may also have cough, joint pain, abdominal pain, and back pain. Symptoms tend to last for about 2 weeks.

Symptoms of epidemic typhus are initially similar to those of endemic typhus, but they become more severe. The rash may cover the entire body except the palms of the hands and the bottoms of the feet. Other serious symptoms that can occur include delirium, stupor, bleeding into the skin (petechiae), delirium, low blood pressure, and potentially life-threatening shock.

Typhus is not contagious since it does not spread from person to person. However, people residing in areas with active typhus outbreaks are at risk for the illness due to the presence of the fleas, lice, or chiggers that spread the bacteria.

Risk factors for typhus include living in or visiting areas where the disease is endemic. These tend to be areas of the world in which infected rodent populations are high, such as areas of overcrowding and poor hygiene like refugee camps. These situations allow infected rodents to come into close contact with people, allowing spread of the illness by fleas or lice.

Sometimes people confuse the terms typhus and typhoid fever. These are different diseases with different causes, modes of spread, and treatments. Typhus spreads by Rickettsia bacteria, while typhoid fever spreads by Salmonella bacteria.

Blood tests are available that can demonstrate antibodies to the bacteria that cause the disease and confirm the infection is present. Other tests can look for the genetic material of the bacteria in blood or tissue samples. However, these tests are not available in many areas of the world where outbreaks may occur.

Often a primary care physician, pediatrician, emergency medicine physician, or internal medicine specialist is the first person to evaluate and treat people who develop febrile illnesses. If medical professionals suspect or confirm a case of typhus, they may consult a specialist in infectious diseases.

The antibiotic doxycycline effectively treats the organisms that cause typhus. It is most effective when given soon after the onset of symptoms and signs. Most people recover rapidly after receiving early treatment.

If people with typhus get an early diagnosis and treatment, almost all will recover with an excellent prognosis. However, undiagnosed or untreated typhus may have worse outcomes, depending on the type of typhus. Untreated endemic typhus has a death (mortality) rate of less than 2%, but the death rate of untreated epidemic typhus ranges from about 10%-60%. Older people and those with chronic medical conditions are at greatest risk of death from untreated typhus.

Most people who receive treatment recover without complications. In people whose treatment is delayed or in untreated infections, complications can include problems with kidney function, pneumonia, brain and central nervous system problems, hepatitis, bleeding into the gastrointestinal tract, and low blood pressure that may result in shock. In epidemic typhus, some patients can stay infected without symptoms after they first get the disease. The patients then can get a relapse during a time of immune system suppression. The recurring disease (referred to as Brill-Zinsser disease) tends to be milder than the initial infection

There are no commercially available vaccines to prevent any of the forms of typhus.