|Year : 2014 | Volume
| Issue : 2 | Page : 147-151
An outbreak of Vibrio cholerae in Vikas Nagar, Chandigarh, India
Sonia Puri, Sandeep Singh Sarpal, Akshay Kumar, Naveen Krishan Goel
Department of Community Medicine, Government Medical College and Hospital, Sector 32, Chandigarh, India
|Date of Web Publication||4-Feb-2014|
Sandeep Singh Sarpal
HNO 1613, SEC 51 B, Chandigarh
Source of Support: None, Conflict of Interest: None
Background : On 1 July 2012, a large number of cases of acute diarrheal episodes were reported in Vikas Nagar, Chandigarh. A rapid response team was sent to investigate this outbreak on 3 July 2012. Aim : To determine the reasons for the outbreak and to focus on the identification of a gap in the management of the epidemic by applying remedial measures in the Vibrio cholera outbreak in the Vikas Nagar area of Chandigarh district. Materials and Methods : A house-to-house survey of 2765 houses was performed with 20 teams of Auxillary Nurse Midwife ANM/Anganwadi workers. Information regarding age, sex, place of residence, occupation, date of onset and treatment history and laboratory finding were collected. Environmental investigation and laboratory investigation of the stool samples were also performed. As the study was conducted during an emergency response to the outbreak, and was designed to provide information to orient the public health response, ethical approval was not required. Remedial measures were implemented. Results : A total of 1875 patients reported to the various health facilities of the Vikas Nagar area with complaints of increased frequency of loose watery diarrhea and a few had vomiting episodes during the time period of 1 - 14 July 2012. Four deaths were reported. Three hundred eighteen (318) cases were found in the house-to-house survey of 2765 houses of the area. Twenty-six percent of the cases were in the age group of <5 years. Hospitalization was required in 12.9% of the cases, while 87.1% were managed in the Outpatient Department. Eight samples were found to be positive for Vibrio cholera El Tor Serotype, Ogawa in samples from the house-to-house survey. A coliform count of >1800 MPN/100 mL was reported from 10 water samples. Investigations revealed that the epidemic was waterborne. Leakages in the pipes were found at many places leading to mixing of water with drainage, and water samples collected from the houses of the cases were found to be positive for Vibrio cholerae. Conclusion : Among the identified gaps, delays in the initiation of the investigation of the epidemic and pipe leakages were the most important. In India, waterborne epidemics are usual occurrences during the year. In this scenario, proper monitoring of water sources, proper sewage disposal, sanitation measures and creating awareness among the people should be undertaken.
Keywords: Cholera, investigation, India, outbreak
|How to cite this article:|
Puri S, Sarpal SS, Kumar A, Goel NK. An outbreak of Vibrio cholerae in Vikas Nagar, Chandigarh, India. Med J DY Patil Univ 2014;7:147-51
|How to cite this URL:|
Puri S, Sarpal SS, Kumar A, Goel NK. An outbreak of Vibrio cholerae in Vikas Nagar, Chandigarh, India. Med J DY Patil Univ [serial online] 2014 [cited 2019 Mar 25];7:147-51. Available from: http://www.mjdrdypu.org/text.asp?2014/7/2/147/126320
| Introduction|| |
Cholera is a clinical - epidemiologic syndrome caused by ingestion of food and water contaminated with the bacterium Vibrio cholerae. , There are an estimated 3-5 million cases of cholera worldwide, from which about 120,000-100,000 patients die every year. The first known pandemic of cholera originated in the Ganges river delta in India in 1817.  Since then, there have been seven pandemics of cholera, of which six occurred in India, except the last one that occurred in Indonesia in 1961. 
Cholera is a bacterial infection spreading via the feco - oral route, leading to an acute diarrheal disease with a large cluster of cases.  In its severe form, cholera gravis, the clinical disease, is characterized by the passage of voluminous stools of rice water character that rapidly lead to dehydration, hypovolemic shock, acidosis and death if prompt and appropriate treatment is not initiated. Studies have shown that up to 80% of the cases of acute diarrhea can be treated successfully with timely intervention like oral rehydration. , The environment plays a crucial role in cholera as it can spread both through fecal contamination of food and water by humans and through independent propagation of the pathogen in the environment. , Cholera has been regularly resurfacing in and around Chandigarh, coinciding with the onset of the monsoon season generally from June to September, for the past years. ,,
The importance of obtaining epidemiological data on diarrheal outbreaks lies in formulating preparedness plans to suit a particular affected area with the population-specific needs. Quick actions taken with simple and rapid field epidemiological (shoe leather epidemiology) and laboratory investigations together can curb such an outbreak before it progresses into an epidemic/larger outbreak leading to higher morbidity/mortality. 
The main aim of the study was to determine the causative factor for outbreak in Vikas Nagar, Chandigarh, such that remedial measures could be taken in time for its control.
| Materials and Methods|| |
After receipt of information about an outbreak of gastroenteritis by the surveillance team in Vikas Nagar, a rapid response team from the Government Medical College and Hospital, Sector 32, Chandigarh, undertook the management and investigation of the epidemic on 3 July 2012. A case of cholera was defined as the occurrence of diarrhea and/or vomiting clinically. And, a confirmed case of cholera was defined as clinical illness with laboratory confirmation of infection and isolation of cholera toxin producing Vibrio cholerae serovar O1 or O139 from the vomitus or the stool.  From the history of the patients visiting the Outpatient Department (OPD) of the Community Health Centre Manimajra, Government Multi-Speciality Hospital Sector 16 and Tertiary Institute Government Medical College and Hospital Sector 32, Chandigarh, the affected localities were identified. A total of 2765 houses with a population of around 15,000 of Vikas Nagar were surveyed intensively with the help of Anganwadi workers/ANMs (3-5 th July). Active search for the cases was carried out by 20 teams (two members in each) and line listing of cases was performed.
Information regarding age, sex, place of residence, occupation, date of onset and treatment history and laboratory finding were collected. The hypotheses were generated based on the characteristics of the person and time and place of the outbreak. The epidemic curve was constructed to describe the development of the outbreak over time and cases were plotted on the geographical map of the area to plan action for control of the outbreak.
After reviewing the descriptive epidemiology and hypotheses-generating interviews, epidemic occurrence pointed to a contaminated water supply. The investigation teams visited house-to-house and collected information regarding water quality, sources of water supply and drainage system, information of mass gathering as well as exposure to mass food consumption. Officials from the water supply department and the local community members were also interviewed to enquire about the general water supply and sanitation situation and random samples of water from households and all the municipal wells of Vikas Nagar were also taken using standard techniques.
Food and water samples were also collected from various commercial establishments and vendors operating in the area. A total of 318 cases were found in the house-to-house survey of 2765 houses of the area during 3-5 July. Water samples were found to be positive for coliform count and Vibrio cholerae. One local food joint (dhaba) where food and water samples were contaminated was closed with the help of food administration authorities. Instructions were also passed to local vendors selling food in unhygienic conditions with the help of administrative machinery for better compliance.
The community was given IEC materials, chlorine tablets and oral rehydration solution (ORS) packets. All the new identified cases were referred to the OPD for general examination and stool examination.
Most of the patients had loose rice watery diarrhea. Stool samples were collected from patients from the cases requiring hospitalization. These were inoculated in alkaline peptone water and tested using standard bacteriological techniques.
This study was conducted as an emergency response to the cholera outbreak and was designed to provide information to orient the public health response; hence, ethical approval was not sought prior to the survey. It was undertaken as a public health practice rather than as a research.  Privacy, confidentiality and rights of patients were ensured during and after the conduct of the study. Oral informed consent was obtained from the participant of each household after detailed explanation of the existence of an outbreak, the objective of the study and the planed use of the information were explained. Moreover, health education was carried out in each household regarding cholera transmission and prevention. The information was entered and analyzed anonymously. The study was implemented in collaboration with the local administrative machinery including the health officials after obtaining authorization to carry out the survey.
| Results|| |
Vikas Nagar in Mauli Jagran, Chandigarh, is a rehabilitated area of slum dwellers where one-room tenements that had been allotted to people for rehabilitation have been extended to multilevel houses over the years. The infrastructure that was initially meant to provide for single storey houses is now catering to at least three times that population as they have constructed multilevel houses in place of the single storey tenements.
The geographical map of the affected area was structured by the survey team during their visit to the area. The residence of the cases was plotted on the map to determine the place distribution of the outbreak [Figure 1].
|Figure 1: Geographical map of Vikas Nagar, Chandigarh, showing the affected areas during the outbreak|
Click here to view
A total of 1875 patients reported to the OPD of the Vikas Nagar area with complaints of increased frequency of loose watery diarrhea and a few had vomiting episodes during the time period of 1-14 July 2012. Of these, 1445 (77.1%) cases were treated on an OPD basis while 430 (22.9%) cases were referred to the tertiary institutes for treatment [Figure 2].
Forty samples were found to be positive for coliform count and 15 were found positive for Vibrio cholerae. A coliform count of >1800 MPN/100 mL was reported from 10 water samples.
The location of the houses from where these samples were taken was plotted on the map of the area to look for distribution of the outbreak. Three hundred and eighteen cases were found in the house-to-house survey of 2765 houses of the area. One hundred and sixty-nine (53%) patients were male and 149 (47%) were female.
Of the 318 cases, 26.4% cases were in the age group of ≤5 years, followed by 21.1% cases in the age group of 16-25 years. 4.1% of the cases were seen in the age group of >55 years [Table 1].
27.6% of the cases were students, 26.4% were children less than 5 years old while 22.6% were housewives [Table 2].
Twenty-seven percent of the cases reported passage of ≥3 stools for the past 2 days, 20.7% for the past 3 days and 17.2% for the past 1 day. 57.5% reported the passage of rice watery stools [Table 3].
5.6% of the patients reported a history of fever ≥3 days [Table 4].
69.1% of the cases were taking ORS and medication, while 10.3% were only taking medicines and 9.1% cases were not taking anything [Table 5].
12.9% of the cases required hospitalization, while 87.1% were managed in the OPD [Table 6].
60.3% were using plastic containers for storing water, followed by 26.7% who using buckets while 10.1% were using filters [Table 7].
Being a rehabilitated colony, where one-room tenements were allotted to people, it has been extended to multilevel houses over the years. The main source of water was piped water supplied by the municipal corporation to the houses.
From the patients hospitalized after the house-to-house survey, eight stool samples were found to be positive for Vibrio cholera El Tor Serotype, Ogawa.
| Discussion|| |
Unauthorized colonies and the rapid expansion of urban slums are creating a burden on the infrastructure of Chandigarh. In rehabilitation colonies, one-room tenements allotted to people for rehabilitation have been extended to multilevel houses over the years. The infrastructure that was initially meant to provide for single storey houses is now catering to at least three times that population. The pipelines that were laid for supplying water to cater to these houses are not being able to meet the needs of the people. Because of the low pressure, water cannot reach the upper storeys, leading to the installation of water boosters on the direct supply line that caused problems in the supply and quality of water.
Four tube wells were supplying fresh water in the area. The water supply to the area was intermittent. Maximum cases were found in the vicinity of tube well number 1. Contaminated water remains the prime vehicle for outbreaks of cholera in developing countries like India. Because of poor sanitation practices, fecal contamination through leakages of water sources of households could be one of the possibilities.
The third target of the Seventh Millennium Development Goal of the United Nations proposes to halve the proportion of people who are unable to reach or afford safe drinking water between 1990 and 2015.  As per the United Nations' criteria, improved drinking water sources include household water connections, public water pipelines, bore wells and protected dug wells, springs and rainwater collection. 
National surveys have shown that only 42% of the households in India have piped water supply as a source of drinking water.  The proportion of people using an improved sanitation facility remains a great challenge. Improper sanitary conditions lead to outbreaks of waterborne diseases.  From a dismal 7% in 1990, this figure has only improved up to 31% in 2008. Seventeen percent of the households in urban areas have no facilities of toilets in India, while 24% are sharing toilet facilities with other households. Twenty-six percent of the households throw child waste in the garbage, while 44% leave it in the open. 
It was also noticed that once the news of epidemic spreads in the area through various channels, a panic-like situation is created in the community. One of the peculiar findings during the field survey seen was a local vendor selling bottled water in the area on the pretext of being safe, but, on inquiry, it was found to be non-branded, bottled tap water, and sale of this water was stopped with the help of the administrative machinery.
Limitations of the Study
Laboratory confirmation of cholera could be carried out on a limited number of patients. We could not exclude other causes either acting together or on their own to cause the outbreak. Secondly, patients with complaints of diarrhea, vomiting and dehydration, irrespective of lab confirmation, were also treated. Thirdly, on asymptomatic persons, stool examination was not carried out. Fourthly, the residual chlorine levels determined at the source were 1.5-2 mg/dL; however, these levels were not determined at the household levels of individual consumers. The above limitations could have had an impact on the association of the outbreak and Vibrio cholerae, but either way the recommendations would be the same.
For immediate remedial action, the residents of the area were informed not to panic, with proper education regarding safe drinking water, use of chlorine tablets and proper sanitation measures by the team performing the house-to-house survey. Super chlorination of water sources was done during the outbreak and chlorine tablets were distributed along with Information Education and Communication materials. ORS was also distributed into the community during the surveys. The residents of the area, especially the housewives, were educated regarding proper household water storage, water disinfection by boiling and chlorination, healthy sanitation measures like clean sewage treatments and proper hand washing. Further regular monitoring of chlorination of water by the health authorities is required to forestall such outbreaks in the future.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]