---

Background
The causative agent of epidemic typhus fever, Rickettsia prowazekii, is transmitted by the human body louse, which becomes infected by feeding on the blood of patients with acute epidemic typhus fever. Infected lice excrete rickettsia onto the skin while feeding on a second host, who becomes infected by rubbing louse faecal matter or crushed lice into the bite wound.
The incubation period is 1–2 weeks (usually 12 days). The onset is variable but often sudden, with high fever, chills, headache, prostration, coughing and severe muscular pain. After 5–6 days, a macular skin eruption appears, initially on the upper trunk, which then spreads to the entire body excepting, usually, the face, palms and soles of the feet. The case–fatality rate is up to 40% in the absence of specific treatment.
Louse–borne typhus fever is the only rickettsial disease that can cause explosive epidemics. Humans are the only reservoir and are responsible for maintaining the infection during inter–epidemic periods. In the past, it was associated with wars and human disasters. Outbreaks occur in colder areas where people live in crowded, unhygienic, louse–infested conditions. Milder symptoms of louse–borne typhus can occur years after the primary attack (Brill–Zinsser disease).

Epidemiology
There were no cases of epidemic typhus fever in Taiwan. Early detection of infected cases by active and passive surveillance system can implement early response activities and reduce the risk of local transmission.

Epidemic Typhus Fever Surveillance in Taiwan

1. Taiwan National Infectious Disease Statistics System–Epidemic Typhus Fever
2. Self–reporting through toll–free 1922 hotline or local public health authority.

Prevention and Control

1. Insecticidal powders are available for body-louse control and treatment of clothing for those at high risk of exposure.
2. Body lice usually infest persons who do not launder and change their clothes regularly.
   • (1)Bathe frequently and change clothes regularly.
   • (2)Machine wash and dry infested clothing and bedding using the hot water laundry cycle and the high heat drying cycle.

FAQs

1. What is epidemic typhus fever?
   • Epidemic typhus fever is a rickettsial disease with variable onset, but is often characterised by the sudden appearance of headaches, chills, prostration, high fever, coughing and severe muscular pain. After 5–6 days, a macular skin eruption develops first on the upper trunk and spreads to the rest of the body but usually not to the face, palms of the hands or soles of the feet.
2. How are epidemic typhus fever transmitted?
   • The causative agent, Rickettsia prowazekii, is transmitted by the human body louse which is infected while feeding on the blood of patients with acute epidemic typhus fever. A Rickettsia–harboring louse bites a second host to engage in a blood meal and causes a pruritic reaction on the host's skin. The louse defecates as it eats; when the host scratches the site, the lice are crushed, and the Rickettsia–laden excrement is inoculated into the bite wound. The Rickettsia travel to the bloodstream and rickettsemia develops.
3. How to prevent the epidemic typhus fever?
   • Primary prevention of louse-borne typhus relies on measures to avoid infestation with body lice, and cleanliness is important in preventing infestation by body lice. The following are steps that can be taken to help prevent and control the spread of body lice:
     • (1)Insecticidal powders are available for body-louse control and treatment of clothing for those at high risk of exposure.
     • (2)Bathe frequently and change clothes regularly.
     • (3)Machine wash and dry infested clothing and bedding using the hot water laundry cycle and the high heat drying cycle.

More Information

1. WHO|Typhus fever (Epidemic louse–borne typhus)
2. USA CDC|Rickettsial & Related Infections
3. USA CDC|Lice–Body Lice
4. USA CDC|Epidemic Typhus
5. ECDC|Facts about epidemic louse-borne typhus