[2] Epidemic typhus generally occurs in outbreaks when poor sanitary conditions and crowding are present.

[7] The name comes from the Greek tûphos (τῦφος), meaning 'hazy' or 'smoky' and commonly used as a word for delusion, describing the state of mind of those infected.

[citation needed] Other signs of meningoencephalitis include sensitivity to light (photophobia), altered mental status (delirium), or coma.

These symptoms include fever, headaches, chills, swollen lymph nodes, nausea/vomiting, and a rash at the site of infection called an eschar.

It can also be done with either immunohistochemistry (IHC) or polymerase chain reaction (PCR) tests excluding scrub typhus.

[17] The American Public Health Association recommends treatment based upon clinical findings and before culturing confirms the diagnosis.

Since the late 20th century, cases have been reported in Burundi, Rwanda, Ethiopia, Algeria, and a few areas in South and Central America.

[22][23][24][25] Except for two cases, all instances of epidemic typhus in the United States have occurred east of the Mississippi River.

[26] Sylvatic cycle (diseases transmitted from wild animals) epidemic typhus remains uncommon in the US.

[27] An outbreak of flea-borne murine typhus was identified in downtown Los Angeles, California, in October 2018.

[28] The first reliable description of typhus appears in 1489 AD during the Spanish siege of Baza against the Moors during the War of Granada (1482–1492).

These accounts include descriptions of fever; red spots over arms, back, and chest; attention deficit, progressing to delirium; and gangrenous sores and the associated smell of rotting flesh.

During the Lent assizes court held at Taunton in 1730, gaol fever caused the death of the Lord Chief Baron, as well as the High Sheriff, the sergeant, and hundreds of others.

During a time when persons were executed for capital offenses, more prisoners died from 'gaol fever' than were put to death by all the public executioners in the British realm.

In May 1750, the Lord Mayor of London, Sir Samuel Pennant, and many court personnel were fatally infected in the courtroom of the Old Bailey, which adjoined Newgate Prison.

[34] A major epidemic occurred in Ireland between 1816 and 1819, during the famine caused by a worldwide reduction in temperature known as the Year Without a Summer.

[citation needed] In 1922, the typhus epidemic reached its peak in Soviet territory, with some 20 to 30 million cases in Russia.

[44] In Russia during the civil war between the White and Red Armies, epidemic typhus killed 2–3 million people, many of whom were civilians.

[47] On 6 March 1939, Prime Minister of France Édouard Daladier stated to the French parliament, he would return 300,000 of the Spanish refugees fleeing from the 1938 Spanish Civil War; reasons included the typhus spread in the French refugee camps, as well as France's sovereign recognition of Francisco Franco.

Pictures of mass graves including people who died from typhus can be seen in footage shot at Bergen-Belsen concentration camp.

[50] Beginning in 2018, a typhus outbreak spread through Los Angeles County primarily affecting homeless people.