What Does Typhus Do to the Body?

I've been reading about the typhus outbreak on the West Coast. I know someone who works in the Los Angeles area, and he says he sees rats in the alley behind his workplace all the time. I know you can get typhus from fleas and rats, but I'm unclear on how you know if you have typhus. What does typhus do to the body? What are the signs and symptoms of typhus?

Typhus occurs after bacteria (Rickettsia) transfer to humans, usually by vectors such as fleas or lice that have acquired the bacteria from animals such as rats, cats, opossums, raccoons, and other animals. Endemic typhus (mainly caused by R. typhi) is also termed murine typhus and "jail fever." "Endemic typhus" also means that an area or region has an animal population (usually mice, rats, or squirrels) that has members of its population continually infected with R. typhi that through flea vectors can incidentally infect humans.

Epidemic typhus (caused by R. prowazekii) is the more severe form of typhus. It has also been termed recrudescent or sporadic typhus. "Epidemic typhus" also means that a few animals, (usually rats) via lice vectors, can incidentally infect large numbers of humans quickly when certain environmental conditions are present (poor hygiene, crowded human living conditions) with the more pathogenic R. prowazekii. Epidemic typhus has a milder form termed Brill-Zinsser disease, which occurs when R. prowazekii bacteria reactivate in a person previously infected with epidemic typhus.

Symptoms of endemic typhus develop within about one to two weeks after initial infection and may include a high fever (about 105 F), headache, malaise, nausea, vomiting, and diarrhea. A petechial rash on the chest and abdomen typically begins about four to seven days after the initial symptoms above develop, and the rash often spreads. Some patients may also have a cough and abdominal pain, joint pain, and back pain. Symptoms may last for about two weeks and, barring complications or death (less than 2% die), symptoms abate.

However, epidemic typhus symptoms, although initially similar to endemic typhus, become more severe. The rash may cover the entire body except the palms of the hands and the bottoms of the feet. Patients may develop additional symptoms of bleeding into the skin (petechiae), delirium, stupor, hypotension, and shock, which can be life threatening.

Typhus risk factors include living in or visiting areas where the disease is endemic. These include many port cities where rat populations are high, and areas where trash accumulates and hygiene may be low. Disaster zones, homeless camps, poverty-stricken areas, and other similar situations that allow rodents to come into close contact with people represent the greatest threats. These are the same type of conditions that lead to outbreaks of cholera, tuberculosis, and viral diseases like influenza. Spring and summer months are when fleas (and ticks) are most active, but infections can occur any time of the year.

For more information, read our full medical article on typhus.