Cholera Epidemic in and Around Kolkata, India: Endemicity and Management


Shyamapada Mandal

  DOI 10.5001/omj.2011.71  
Department of Zoology, Gurudas College, Narkeldanga, Kolkata-700 054, India.

Received: 01 Apr 2011
Accepted: 13 May 2011

*Address correspondence and reprints request to: Dr. Shyamapada Mandal, Department of Zoology, Gurudas College, Narkeldanga, Kolkata-700 054, India. Email:

How to cite this article

Mandal S. Cholera Epidemic in and Around Kolkata, India: Endemicity and Management. Oman Med J 2011 Jul; 26(4):288-289.

How to cite this URL

Mandal S. Cholera Epidemic in and Around Kolkata, India: Endemicity and Management. Oman Med J 2011 Jul; 26(4):288-289. Available from


Cholera, an acute diarrhoeal illness caused by toxigenic strains of Vibrio cholerae serogroups O1 and O139, has the potential to appear in explosive outbreak, epidemic and even pandemic. In 1849, the British physician John Snow (1813-1858) explained the association of a cholera outbreak in London with contamination of the drinking water supply by human excreta. Later, in 1854, Filippo Pacini (1812-1883), an anatomist from Italy, and in 1883, Robert Koch (1843-1910) the German bacteriologist, discovered vibrio cholerae as the responsible microbial agent for cholera.

Since 1817, the world has already faced six pandemics of cholera, and the seventh one that began in 1961 is in progress and has affected greatly the Indian subcontinent along with almost the whole world.1,2 Nevertheless, cholera is an under-recognized problem in India; its endemicity in the country has been evidenced since the ancient times,3 and the Kolkata city of the West Bengal state located in the Gangetic delta has been hailed as the "homeland of cholera," with regular outbreaks and pronounced seasonality.4-9 India, where the disease is endemic, cholera outbreaks occur every year in between dry (March-April) and rainy (September-October) seasons. A high population density, along with unsafe drinking water, open drains and poor sanitation provide optimal niche for survival, sustenance and transmission of V. cholerae in this part of the globe.

At the beginning of the 21st century, cholera remains an epidemic or endemic disease in much of the world, and many developing countries still endure frequent outbreaks due to the lack of basic sanitation services and clean water, though in order to manage outbreaks WHO recommended emergency interventions, including excreta disposal, sanitary measures and water quality monitoring.10,11 India, which comprises 28 states and 7 union territories, has a total population of 1.15 billion people, and approximately two thirds of the population live in rural areas, where only 28% use piped drinking water and 26% access to good sanitation.12 The oral-faecal route of transmission of V. cholerae is linked to the lack of safe drinking water and sanitation facilities for people living under low socio-economic conditions; hence, the Indian sub-continent has been the epi-centre for cholera, which continues to be an important public health problem in the country, and Kolkata (a metropolitan city in India) is plagued by the reoccurrence of cholera outbreaks8,9,13; also, the dense and large slum population facilitated the cholera outbreaks.8,9,13

In Kolkata, as in other parts of the globe, cholera is changing epidemiologically. The city faced several outbreaks of cholera due to V. cholerae strains belonging to both the serogroups O1 and O139, and the biotypes, classical and El Tor of O1 serogroup. Strains of classical biotype, the reason for the past six pandemics, are suggested to be more toxigenic than El Tor strains.14 There are evidences of spread of El Tor strains harboring classical cholera toxin (CT) gene,15-17 and the replacement of the seventh pandemic El Tor strains by the classical CT producing El Tor strains as well.15,18,19 Moreover, of the two biotypes, El Tor strains have better adaptability to survive in the environment and in the human host,20 and currently, the classical biotype is believed to be extinct.18,21 However, the fact mentioned above has been taken as the evolutionary optimization of El Tor biotype, which could represent a new and more significant emerging form of the El Tor biotype of V. cholerae. Plus, the constant changes in the characteristics of the toxigenic V. cholerae, in the serotypes predominating in outbreaks, may be a survival advantage to the strains in the wake of host with less susceptibility to the pathogen, and this has been evidenced by the fact that the V. cholerae O1 strains as have been demonstrated to interconvert and to undergo serotype switching between Ogawa and Inaba.22 The problem has been compounded by the recent emergence of multidrug resistant V. cholerae strains, which limit the therapeutic potential of the drugs, and the overall evolution of antibiotic resistance sometimes attributed to R-plasmid,9,23 mainly because of the selective forces imposed due to the overuse of antibiotics.

As is true for other bacterial diseases transmitted via faecal-oral route, an adequate supply of potable water, improved sanitation and promotion of good hygienic practices, mainly in developing countries like India, remain the mainstay for preventing both endemic and epidemic cholera. Also, vaccination against cholera has been recommended as an attractive additional tool to combat the disease in endemic areas.24 But, new epidemic strains are likely to develop, evolve, and spread, and thus V. cholerae cannot be eradicated; it is a part of the normal flora and ecology of the surface water of this planet, where we have to learn to coexist with the V. cholerae. However, continued monitoring and surveillance of all cholera outbreaks becomes a necessity, in order to check the changing trends of antimicrobial resistance patterns among V. cholerae strains, and vigilance of R-plasmid is a must to combat drug resistance by preparing proper antibiotic treatment regimen for severe cholera cases.9,25


The author reported no conflict of interest and no funding was received on this work.


1. Barua D. Cholera. Proc R Soc Med 1972;65:11-16.

2. Tavana M, Fallah Z, Ataee RA. Is cholera outbreak related to climate factors? Report of seven year study from 21 March 1998-21 March 2004 in Iran. J Med Sci 2006;6:480-483 .

3. Burrell RM. The 1904 epidemic of cholera in Persia: some aspects of Qājār society. Bull Sch Orient Afr Stud 1988;51(2):258-270.

4. Barua D, Mukherjee AC, Sack B. El Tor vibrios from cases of cholera in Calcutta. Bull Calcutta Sch Trop Med 1964 Apr;12:55-56.

5. Gupta DN, Sarkar BL, Bhattacharya MK, Sengupta PG, Bhattacharya SK. An El Tor cholera outbreak in Maldah district, West Bengal. J Commun Dis 1999 Mar;31(1):49-52.

6. Sengupta PG, Sircar BK, Mondal S, Gupta DN, Bhattacharya SK, De SP, et al. An ElTor cholera outbreak in an endemic community of Calcutta. Indian J Public Health 1989 Jan-Mar;33(1):21-25.

7. Sur D, Sarkar BL, Manna B, Deen J, Datta S, Niyogi SK, et al. Epidemiological, microbiological & electron microscopic study of a cholera outbreak in a Kolkata slum community. Indian J Med Res 2006 Jan;123(1):31-36.

8. Sur D, Dutta S, Sarkar BL, Manna B, Bhattacharya MK, Datta KK, et al. Occurrence, significance & molecular epidemiology of cholera outbreaks in West Bengal. Indian J Med Res 2007 Jun;125(6):772-776.

9. Mandal S, Mandal MD, Pal NK. Plasmid mediated antibiotic resistance of Vibrio cholerae O1 biotype El Tor serotype Ogawa associated with an outbreak in Kolkata, India. Asian Pacific J Trop Med 2010;3:637-641 .

10. World Health Organization. Global task force on cholera control. Cholera outbreak: assessing the outbreak response and improving preparedness. WHO/CDS/CPE/ZFK/2004.4. Geneva, Switzerland: WHO.

11. World Health Organization. Global task force on cholera control. First steps for managing an outbreak of acute diarrhoea. WHO/CDS/CSR/NCS/2003.7 Rev.1, Geneva, Switzerland: WHO.

12. Ministry of Health and Family Welfare. States profile. New Delhi: MOHFW, Government of India.

13. Bhunia R, Ramakrishnan R, Hutin Y, Gupte MD. Cholera outbreak secondary to contaminated pipe water in an urban area, West Bengal, India, 2006. Indian J Gastroenterol 2009 Mar-Apr;28(2):62-64.

14. Huq A, Parveen S, Qadri F, Sack DA, Colwell RR. Comparison of Vibrio cholerae serotype 01 strains isolated from patients and the aquatic environment. J Trop Med Hyg 1993 Apr;96(2):86-92.

15. Nair GB, Qadri F, Holmgren J, Svennerholm AM, Safa A, Bhuiyan NA, et al. Cholera due to altered El Tor strains of Vibrio cholerae O1 in Bangladesh. J Clin Microbiol 2006 Nov;44(11):4211-4213.

16. Goel AK, Jain M, Kumar P, Jiang SC. Molecular characterization of Vibrio cholerae outbreak strains with altered El Tor biotype from southern India. World J Microbiol Biotechnol 2010 Feb;26(2):281-287.

17. Goel AK, Jain M, Kumar P, Bhadauria S, Kmboj DV, Singh L. A new variant of Vibrio cholerae O1 El Tor causing cholera in India. J Infect 2008 Sep;57(3):280-281.

18. Nair GB, Faruque SM, Bhuiyan NA, Kamruzzaman M, Siddique AK, Sack DA. New variants of Vibrio cholerae O1 biotype El Tor with attributes of the classical biotype from hospitalized patients with acute diarrhea in Bangladesh. J Clin Microbiol 2002 Sep;40(9):3296-3299.

19. Kumar P, Jain M, Goel AK, Bhadauria S, Sharma SK, Kamboj DV, et al. A large cholera outbreak due to a new cholera toxin variant of the Vibrio cholerae O1 El Tor biotype in Orissa, Eastern India. J Med Microbiol 2009 Feb;58(Pt 2):234-238.

20. Finkelstein RA. Vibrio cholerae O1 and O139, and other pathogenic vibrios. 2006.

21. Safa A, Sultana J, Dac Cam P, Mwansa JC, Kong RY. Vibrio cholerae O1 hybrid El Tor strains, Asia and Africa. Emerg Infect Dis 2008 Jun;14(6):987-988.

22. Garg P, Nandy RK, Chaudhury P, Chowdhury NR, De K, Ramamurthy T, et al. Emergence of Vibrio cholerae O1 biotype El Tor serotype Inaba from the prevailing O1 Ogawa serotype strains in India. J Clin Microbiol 2000 Nov;38(11):4249-4253.

23. Prescott LM, Datta A, Datta GC. R-factors in Calcutta strains of Vibrio cholerae and members of the Enterobacteriaceae. Bull World Health Organ 1968;39(6):971-973.

24. Manna B, Niyogi SK, Bhattacharya MK, Sur D, Bhattacharya SK. Observations from diarrhoea surveillance support the use of cholera vaccination in endemic areas. Int J Infect Dis 2005 Mar;9(2):117-119.

25. Mandal S, Pal NK, Chowdhury IH, Debmandal M. Antibacterial activity of ciprofloxacin and trimethoprim, alone and in combinittion, against Vibrio cholerae O1 biotype El Tor serotype Ogawa isolates. Pol J Microbiol 2009;58(1):57-60.