Year : 2007 | Volume
: 32 | Issue : 1 | Page : 84--85
An outbreak investigation of viral hepatitis E in south Dumdum municipality of Kolkata
P Das, KK Adhikary, PK Gupta
Deptt. of Community Medicine, NRS Medical College, 138, AJC Bose Road, Kolkata - 700014., India
Deptt. of Community Medicine, NRS Medical College, 138, AJC Bose Road, Kolkata - 700014.
|How to cite this article:|
Das P, Adhikary K K, Gupta P K. An outbreak investigation of viral hepatitis E in south Dumdum municipality of Kolkata.Indian J Community Med 2007;32:84-85
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Das P, Adhikary K K, Gupta P K. An outbreak investigation of viral hepatitis E in south Dumdum municipality of Kolkata. Indian J Community Med [serial online] 2007 [cited 2019 Oct 14 ];32:84-85
Available from: http://www.ijcm.org.in/text.asp?2007/32/1/84/53417
Many communicable diseases are endemic in India. These diseases can cause outbreaks with the potential to spread rapidly and cause many deaths. Recognition of early warning signals, timely investigation and application of specific control measures can limit the spread of the outbreak and prevent deaths. One of such epidemic prone diseases is viral hepatitis.
Inadequate environmental sanitation supports the existence of Hepatitis E virus and essentially it is a waterborne disease. Water or food supplies contaminated by faeces have been implicated in major outbreaks reported in all parts of the world with hot climate.
During earlier part of April 2004, few cases of jaundice were reported at South DumDum Municipality Hospital consecutively for 3-4 days and then it was found that many other cases were reported from a particular area of the Municipality. So, epidemiological investigation was required in this situation to determine the existence of epidemic of jaundice if any, to find out time, place and person distribution of jaundice cases, sources of infection, to identify and characterize the disease agent and to recommend and adopt control measures.
Material and Methods
The place of study was ward number 17 and 19 of South DumDum Municipality, Kolkata. The investigation period was April 2004 to July 2004. A pre-designed semi-structured schedule was utilized to collect the data. Total population of the ward No. 17 and 19 of South DumDum Municipality was taken for this study. The family was used as the sampling unit of the study. Inductive investigation of this jaundice outbreak included case detection, defining population at risk, examining the distribution of cases by time, place and person, consideration of aetiology and source of infection. The affected area was visited with local social health workers of ward No. 17 and 19. Area maps were taken from municipality. Complete enumeration of all the families was done by houseto-house survey using pre-designed schedule. Presence of yellowish discolouration of bulbar conjunctiva and passage of dark coloured urine were the criteria used to define a jaundice case. Source of water for drinking and domestic use, excreta disposal, history of hospital admission for jaundice etc. were collected. Reports of laboratory tests of blood and serum (229 samples) for bilirubin (total and direct), alanine aminotransferase (ALT), HAV IgM, HEV IgM were collected. Samples of drinking water were tested for MPN (most probable number) of coliforms, faecal coliforms and E. coli during the current outbreak. After charging of chlorine through bleaching powder solution at later part of outbreak, again samples of drinking water was tested for the same.
Out of 5656 families surveyed in the community, 819 were found with one or more cases of jaundice. Total jaundice cases were 1137 in this area. In the last 5 years, no documented jaundice case was reported to health authority. Six cases showed positive result for hepatitis E virus. These findings point to the occurrence of viral hepatitis E outbreak.
The following symptoms and signs were recorded from patients i.e. high coloured urine (97.0%), jaundice (95.8%), anorexia (80.3%), nausea and or vomiting (73.7%), weakness (49.3%), backache and headache (38.0%), icterus (68.0%), hepatomegally (67.7%) and hepatic tenderness (21.1%) etc.
Source of water for drinking and domestic use was principally intermittent piped line. Few hand-pumps (2.02%) were also found in the locality. Excreta disposal was not insanitary in most of the houses but the habit of child defaecation in the open drain is still followed. Limited sewerage system like Lalababu Nikashi Nala was the narrow dirty sullage and sewage carrying open drain situated between ward 17 and 19. Leaking drinking water lines were crossing through this drain submerged under filthy liquid. Clustering of cases in families was found around this drain. Few residents were using on-line private booster pumps. Blood samples of 229 symptomatic cases were tested in the laboratory for total and direct bilirubin, alanine aminotransferase (ALT) and six samples were tested for anti-HAV and anti-HEV IgM. More than 1 mg/dl total bilirubin was found in 97 cases (42.46%) whereas >2 mg/dl was found in 81 cases (35.47%). 158 cases (69.0%) showed increased level (=> 41U/L) of ALT. All six samples of blood from jaundice cases were found to be negative for anti-HAV IgM but found to be positive for anti-HEV IgM.
Report of bacteriological examination of drinking water samples (7 numbers) in connection with the outbreak of jaundice revealed that five samples (71.4%) were found highly contaminated. During outbreak at the onset, safe water supply was made available to the inhabitants through movable water tanks and the local people were requested to boil the drinking water till further notice. The appropriate authority was requested to repair the leaking water pipe line. After one day of charging of chlorine through bleaching powder solution, water samples were collected from three public stand-posts. These water samples were found bacteria free. The people were requested to conduct periodic bacteriological check-up and dis-infection of water.
Although occasional outbreaks of Hepatitis A or B had been reported, Hepatitis E Virus caused most of the outbreaks of viral hepatitis in India. Clustering of jaundice cases around the leaking pipe line water supply, presence of poor environmental and sanitary conditions, presence of open-air defaecation, bacteriologically unfit water for consumption, hepatocellular damage assessed by blood biochemistry, presence of anti-HEV IgM in serum of jaundice cases, quick control of outbreak by supplying potable water and repair of water supplying pipe line etc suggested that this outbreak was due to common source type of faeco-orally transmitted Hepatitis E Virus.
The overall attack rate of 4.77% in this study was similar as compared with Gupta et al, 1995  . Variable attack rates ranging from 1.9 to 8.6% have been reported ,, . Age specific attack rate of this outbreak was found to be higher in late adolescents and young adults. Case fatality rate (CFR) was found to be 0.35% in this outbreak and this was lower as compared to Kota (1.0%) and Jhalawar (0.5%) outbreaks. However, none of the pregnant mothers died in this outbreak.
Kolkata was already affected by HEV. Institutional outbreak of hepatitis E was reported from the School of Tropical Medicine, Kolkata in 1995  . Other parts of Kolkata were involved later on  .
This outbreak started in first week of April 2004. The last case was detected on first week of May 2004. No secondary peak was observed in the Epidemic curve. Considering the average incubation period to be usually one month to one and a half months, it was likely that contamination of water occurred during the beginning of first week of March 2004. This summer related episode of viral hepatitis E was found consistent with other outbreaks ,,,.
Measures were taken to control the spread of outbreak to reduce the morbidity and mortality. Hepatitis E outbreak spread rapidly among all groups of people in the area of filthy water supply with a case fatality rate of 0.35%.
We acknowledge the service given by Miss Shyamali Chakraborty a voluntary worker of South DumDum Municipality.[Table 1]
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