Chapter 5 : Epidemic Typhus: a Forgotten but Lingering Threat

Abstract:

The impact of louse-borne, or epidemic, typhus, which is caused by Rickettsia prowazekii, on populations is of historical significance but has passed from current concern. Whenever large numbers of people were crowded together under less than sanitary conditions, typhus appeared. Louse-borne typhus remains endemic in the mountainous regions of the Americas, the Himalayas, Afghanistan, and Africa. The disease is maintained in an endemic cycle of transmission that remains barely detectable. Occasionally, conditions that favor epidemic transmission occur. Epidemic typhus spreads into populations at higher elevations, where colder conditions prevailed and infestations with lice were prevalent. Epidemic typhus is characterized clinically by sudden onset, sustained high fever of about 2 weeks duration, a maculopapular rash, and altered mental state. There is effective antimicrobial therapy for the typhus fevers. The response to tetracyclines or chloramphenicol is rapid and efficacious. Most patients become afebrile within 48 h of treatment, and single-dose doxycycline therapy is effective in epidemic situations. Strategies for control of epidemics of louse-borne typhus in refugee camps must include two elements of intervention: (i) antimicrobial treatment of patients with suspected cases and (ii) delousing of the entire population at risk. Long-term louse control or eradication depends on correction of the complex environmental, economic, cultural, educational, and political factors that contribute to louse infestations.