Most patients receive cladribine by IV infusion once a day for five to seven days, but more patients are being given the option of taking this drug once a week for six weeks. The different dosing schedules used with cladribine are roughly equally effective and safe. Relatively few patients have significant side effects other than fatigue and a high fever caused by the cancer cells dying, although complications such as infection and acute kidney failure have been seen. Pentostatin is chemically similar to cladribine, and has a similar success rate and side effect profile, but it is always given over a much longer period of time, usually one dose by IV infusion every two weeks for 3–6 months. During the weeks following treatment, the patients immune systems are severely weakened, but their bone marrow will begin to produce normal blood cells again. Treatment often results in long-term remission. About 85% of patients achieve a complete response from treatment with either cladribine or pentostatin, and another 10% receive some benefit from these drugs, although no permanent cure for this disease is known. If the cancer cells return, the treatment may be repeated and should again result in remission, although the odds of success decline with repeated treatment. Remission lengths vary significantly, from one year to more than twenty years. The median patient can expect a treatment-free interval of about ten years. 2-Chlorodeoxyadenosine (Cladribine) induced complete responses in patients with hairy cell leukemia resistant to DCF, suggesting a lack of cross-resistance.
Five to nine days after the symptoms have started, a rash typically begins on the trunk and spreads to the extremities. This rash eventually spreads over most of the body, sparing the face, palms, and soles. Signs of meningoencephalitis begin with the rash and continue into the second or third weeks. Other signs of meningoencephalitis include sensitivity to light (photophobia), altered mental status (delirium), or coma. Untreated cases are often fatal. Causes
Multiple diseases include the word "typhus" in their descriptions. Types include:

Prevention
As of 2020, no vaccine is commercially available. A vaccine has been in development for scrub typhus known as the scrub typhus vaccine. Treatment
The American Public Health Association recommends treatment based upon clinical findings and before culturing confirms the diagnosis. Without treatment, death may occur in 10% to 60% of people with epidemic typhus, with people over age 60 having the highest risk of death. In the antibiotic era, death is uncommon if doxycycline is given. In one study of 60 people hospitalized with epidemic typhus, no one died when given doxycycline or chloramphenicol. Epidemiology
According to the World Health Organization, the current death rate from typhus is about one  of every 5,000,000 people per year.Only a few areas of epidemic typhus exist today. Since the late 20th century, cases have been reported in Burundi, Rwanda, Ethiopia, Algeria, and a few areas in South and Central America.Except for two cases, all instances of epidemic typhus in the United States have occurred east of the Mississippi River.