Relapsing fever epidemiology and demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
TBRF is endemic in the western US, southern British Columbia, plateau regions of Mexico, Central and South America, the Mediterranean, Central Asia, and much of Africa. In the United States. LBRF is mainly a disease of the developing world. It is currently seen in Ethiopia and Sudan. Famine, war, overcrowding, and the movement of refugee groups often result in LBRF epidemics. With antibiotic treatment, the mortality of epidemic relapsing fever decreases from 10% to 40% to 2% to 4%.
Epidemiology and Demographics
Prevalnce
- It is reported that 15 million cases of louse-borne relapsing fever (LBRF) and more than 5 million deaths occurred in Africa, Eastern Europe, and Russia in the past.
Incidence
- In the early 1900s, many large epidemics were described, predominantly in Africa, the MiddleEast, India, and China. With improved hygiene, the incidence of epidemic relapsing fever has declined in the 20th century, but the disease continues to be a problem in countries of Africa, Asia, and South America.
- Only in North-Eastern Africa, especially the highlands of Ethiopia where an estimated 10,000 cases of LBRF occur annually and affect mostly homeless people living in very unhygienic and crowded conditions especially during rainy seasons. [1]
- Only a few cases TRBF are reported in the U.S. annually.
Case-fatality rate/Mortality rate
- The death rate for untreated LBRF ranges from 10 - 70%. In TBRF, it is 4 -10%.
- With antibiotic treatment, the mortality of epidemic relapsing fever decreases from 10% to 40% to 2% to 4%.
- Fatalities are lower in tick-borne disease compared to louse-borne disease, with treatment.[2]
Race
- There is no racial predilection to relapsing fever.
Region
- TBRF is endemic in the western U.S., southern British Columbia, plateau regions of Mexico, Central and South America, the Mediterranean, Central Asia, and Africa.
- The first endemic region of TBRF in the US was identified in 1915 in Colorado (Meader 1915). However, the first case was actually in 1905 in New York in a traveler to Texas. Since then, TBRF has been reported in 14 states: Arizona, California, Colorado, Idaho, Kansas, Montana, Nevada, New Mexico, Ohio, Oklahoma, Oregon, Texas, Utah, Washington, and Wyoming.
- Most recent cases and outbreaks have occurred in a rustic cabin or vacation home settings at higher elevations (> 8,000 feet) in coniferous forests in the western U.S.
- TBRF occurs typically in summer months when people are traveling to mountainous areas on vacation. TBRF can occur in winter, mainly when people go into rodent-infested cabins and start fires, warming the place and producing carbon dioxide and warmth that attract the ticks that transmit TBRF.
Developed Countries
- TBRF is reported worldwide, except Antarctica, Australia, and the Pacific Southwest.
Although TBRF was removed from the list of nationally notifiable conditions in 1987, 11 states require TBRF to be reported to their State Health Departments (Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Texas, Utah, Washington, and Wyoming). Other states, such as Montana, may institute reporting in the future. [3]. Most cases of endemic relapsing fever occur in the late spring and summer.
Devloping countries
LBRF is mainly a disease of the developing world. It is currently seen in Ethiopia and Sudan. Famine, war, and the movement and groups of refugees often result in epidemics of LBRF. The largest recent epidemics of LBRF occurred during World Wars I and II. At least 1 million people died during these epidemics.[4] it is currently prevalent in Ethiopia and Sudan.
References
- ↑ Yimer M, Abera B, Mulu W, Bezabih B, Mohammed J (September 2014). "Prevalence and risk factors of louse-borne relapsing fever in high risk populations in Bahir Dar city Northwest, Ethiopia". BMC Res Notes. 7: 615. doi:10.1186/1756-0500-7-615. PMC 4175284. PMID 25196787.
- ↑ Kolarík J (1971). "Different reaction of focal and diffuse epileptic EEG activity to psilocybin". Act Nerv Super (Praha). 13 (3): 215–6. PMID 5000337.
- ↑ http://www.cdc.gov/ncidod/dvbid/RelapsingFever/RF_Epidemiology.htm
- ↑ Cutler S (2006). "Possibilities for relapsing fever reemergence". Emerg Infect Dis. 12 (3): 369–74. PMID 16704771.