Cholera epidemiology and demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editors-In-Chief: Priyamvada Singh, MBBS [2]
Overview
In 2015, 172,454 cases and 1,304 deaths of cholera were reported to WHO worldwide. Outbreaks continued to affect several countries. Overall, 41% of cases were reported from Africa, 37% from Asia and 21% from the Americas.[1] In the early 1980s, death rates are believed to have been greater than 3 million a year. It is difficult to calculate exact numbers of cases, as many go unreported due to concerns that an outbreak may have a negative impact on the tourism of a country.[2] Cholera remains both epidemic and endemic in many areas of the world. Although much is known about the mechanisms behind the spread of cholera, this has not led to a full understanding of what makes cholera outbreaks happen some places and not others. Lack of treatment of human feces and lack of treatment of drinking water greatly facilitate its spread, but bodies of water can serve as a reservoir, and seafood shipped long distances can spread the disease. Cholera was not known in the Americas for most of the 20th century, but it reappeared towards the end of that century and seems likely to persist.[3]
Epidemiology and Demographics
Incidence
- In 2015, 172,454 cases and 1,304 deaths of cholera were reported to WHO worldwide. Outbreaks continued to affect several countries.
- Overall, 41% of cases were reported from Africa, 37% from Asia and 21% from the Americas.[1]
- Worldwide, cholera affects an estimated 1.4 to 4.3 million people, and causes 28,000 to 142,000 deaths a year as of 2012[4][5]
Origin and Spread
Cholera was originally endemic to the Indian subcontinent, with the Ganges River likely serving as a contamination reservoir. It spread by trade routes (land and sea) to Russia, then to Western Europe, and from Europe to North America. It is now no longer considered an issue in Europe and North America, due to filtering and chlorination of the water supply.
Gender
Cholera occurs equally in males and females.
Age
- In non-endemic areas,cholera occurs equally in all age groups.
- In endemic regions, children older than the age of 2 years are most commonly infected which cholera.(Illness is uncommon before the age of 2 yr, likely because of passive immunity)
Geographic Distribution
Cholera in the United States
In the U.S., the occurrence of cholera is very low (0-5 cases per year) and is usually due to ingestion of contaminated food or international travel. There has been a modest increase in imported cases since 1991 related to travel and ongoing epidemics.[6]
Cholera in the Developing World
The highest incidencce of cholera in the developing world occurs in the following regions:
- Africa: Mozambique, Liberia, Democratic Republic of Congo, Niger
- Asia: Indonesia, Bangladesh, India
- The Americas: Dominican Republic, Haiti
Case Fatality Rates
- In 2015, case fatality rates (CFRs) ranged from 0.0% to 11.7% (Globally, the overall CFR was 0.8%)<ref name=WHO-GHO> World Heath Organization. Global Health Observatory (GHO) 2016. dathttp://www.who.int/gho/epidemic_diseases/cholera/case_fatality_rate_text/en/<ref>
- CFRs >1% were reported by 15 countries.
- Of these 15 countries, CFR>5% were reported in Myanmar and Niger.
- Average case fatality rates for Europe and the Americas is estimated to be around 1%.
- At the Treatment Center of the International Center for Diarrheal Disease Research, Bangladesh, less than 1% of patients with severe dehydration die.
- In Africa, a marked decline in case fatality rates has reported since 1970
- in South America, low case fatality rates have been achieved.
References
- ↑ 1.0 1.1 World Health Organization. Global Health Observatory (GHO) data. http://www.who.int/gho/epidemic_diseases/cholera/en/ Accessed on October 5th, 2016
- ↑ Sack DA, Sack RB, Chaignat CL (2006). "Getting serious about cholera". N. Engl. J. Med. 355 (7): 649–51. doi:10.1056/NEJMp068144. PMID 16914700. Unknown parameter
|month=ignored (help) - ↑ Blake, PA (1993). "Epidemiology of cholera in the Americas". Gastroenterology clinics of North America. 22 (3): 639–60. PMID 7691740.
- ↑ World Health Organization. Cholera. (2016) http://www.who.int/mediacentre/factsheets/fs107/en/ Accessed on October 5th,2016
- ↑ Ali M, Lopez AL, You YA, et al. The global burden of cholera. Bulletin World Health Organization 2012; 90: 209–18A.
- ↑ Centers for Disease Control and prevention. Sources of Infection & Risk Factors. http://www.cdc.gov/cholera/infection-sources.html Accessed on October 5th, 2016