Occurrence, significance & molecular epidemiology of cholera outbreaks in West Bengal.

BACKGROUND & OBJECTIVE: Diarrhoeal disease outbreaks are causes of major public health emergencies in India. We carried out investigation of two cholera outbreaks, for identification, antimicrobial susceptibility testing, phage typing and molecular characterization of isolated Vibrio cholerae O1, and to suggest prevention and control measures. METHODS: A total of 22 rectal swabs and 20 stool samples were collected from the two outbreak sites. The V. cholerae isolates were serotyped and antimicrobial susceptibility determined. Pulsed- field gel electrophoresis (PFGE) was performed to identify the clonality of the V. cholerae strains which elucidated better understanding of the epidemiology of the cholera outbreaks. RESULTS: Both the outbreaks were caused by V. cholerae O1 (one was caused by serotype Ogawa and the other by serotype Inaba). Clinically the cases presented with profuse watery diarrhoea and dehydration. All the tested V. cholerae isolates were sensitive to tetracycline, gentamycin and azithromycin but resistance for ampicillin, co-trimoxazole, nalidixic acid, and furazolidone. PFGE pattern of the isolates from the two outbreaks revealed that they were clonal in origin. Stoppage of the source of water contamination and chlorination of drinking water resulted in terminating the two outbreaks. INTERPRETATION & CONCLUSION: The two diarrhoeal outbreaks were caused by V. cholerae O1 (Inaba/Ogawa). Such outbreaks are frequently seen in cholera endemic areas in many parts of the world. Vaccination is an attractive disease (cholera) prevention strategy although long-term measures like improvement of sanitation and personal hygiene, and provision of safe water supply are important, but require time and are expensive.

Multifocal giant cell tumour of bone in a skeletally immature patient--a case report.

Giant cell tumor of bone is usually seen in adults affecting a single bone. Multiple giant cell tumour of bone occurring in skeletally immature patients is extremely rare. Multifocal giant cell tumor of bone in a ten year old boy involving upper end of humerus and tibia is being reported for its extreme paucity in literature.

Outbreak of cholera caused by Vibrio cholerae 01 intermediately resistant to norfloxacin at Malda, West Bengal.

During the end of September 1997, an unusual outbreak of severe dehydrating watery diarrhoea cases and deaths were reported from Malda town. Vibrio cholerae 01 El tor, the causative agent responsible for this episode was isolated from 56.5% of cases sampled. Three of the five drinking water samples were also positive for V cholerae 01. Majority of cases were adults. Isolated strains were uniformly resistant to furazolidone and intermediately to norfloxacin. Indiscriminate use of antibiotic should be discouraged for development of multidrug resistant strains.

Multi-drug resistant non-typhoidal Salmonella spp. associated with acute diarrhoeal disease.

The prevalence of different serotypes of non-typhoidal Salmonella spp. among patients suffering from acute diarrhoea admitted to the Infectious Diseases Hospital, Calcutta was investigated. The predominant serogroup was C and Salmonella infantis was the major serotype isolated followed by S. worthington, S. enteritidis, S. typhimurium, S. weltevereden and S. newport. All the Salmonella strains were isolated from adults. Multidrug resistance to various antimicrobial agents was observed in 37.5 per cent of the strains. All the strains were sensitive to ciprofloxacin, norfloxacin and gentamycin.

An El Tor cholera outbreak in Maldah district, West Bengal.

An outbreak of cholera occurred in Maldah district, West Bengal during July-August 1998. Attack rate was 34/1000. Cases were more (59.3%) amongst adults (> 15 years.). V. cholerae 01 biotype E1 Tor serotype ogawa was isolated as a single pathogen from 52.9% (9/17 samples examined). All V. cholerae strains belonged to phage type 2 (Basu and Mukherjee scheme) and type 27 (new phage type scheme). The strains were resistant to co-trimoxazole, furazolidone, ampicillin, streptomycin and nalidixic acid.

Uncooked rice powder in oral rehydration solution: an alternative to glucose or cooked rice powder.

Glucose-based or rice-based ORS is the standard treatment in acute dehydrating diarrhoea. However, glucose may not be easily available in remote villages and the rice needs to be cooked for rice-based ORS. We embarked on a study to examine whether uncooked rice powder could be used as an alternative to glucose or cooked rice powder in ORS. Initially, 50 adult male patients (aged 18 to 55 yr) were randomized to receive glucose-ORS or uncooked rice ORS, in two equal groups. Subsequently, 20 male children (aged 3 to 12 yr) were also enrolled in the study and received either WHO-ORS or study ORS. All the adult patients and the children could be successfully rehydrated with ORS containing uncooked rice powder. As compared to WHO-ORS, the study ORS significantly reduced stool output (6.60 +/- 1.24 vs. 5.88 +/- 1.34 l), ORS intake (9.17 +/- 1.54 vs 8.24 +/- 1.69 l) and duration of diarrhoea (45.68 +/- 6.91 vs 41.32 +/- 6.03 h). In children also similar results were obtained. No clinical complication (e.g., vomiting, abdominal pain etc.) or abnormality in serum electrolyte concentrations was encountered either in the adults or in the children. Uncooked rice powder containing ORS can be considered as an alternative to glucose-based ORS or rice-based ORS.

Frequency of isolation of toxigenic Clostridium difficile from healthy adults.

An attempt was made to isolate Clostridium difficile from 129 faecal specimens from 87 young and 42 elderly healthy adults. C.difficile was isolated using bacterial culture from 7 (5.4%) specimens and the frequency of isolation of toxigenic C. difficile as detected by cytotoxin (tissue culture) assay was 1.1 per cent and 2.4 per cent in healthy young and elderly adults respectively. The carrier rate of toxigenic C. difficile amongst healthy adults is relatively low in this part of our country.

Distribution of age-specific rotavirus antibody in human: a hospital-based study in Calcutta.

Sera obtained from 332 non-diarrhoeic individuals belonging to different age groups were tested by enzyme-linked immunosorbent assay method for detection of rotavirus antibody. All the sera were found to contain rotavirus antibody in varying titres, the highest being recorded in neonates which declined to the lowest by the age of 6 months with a rapid rise during the next 5 years. This study indicates the acquisition of rotavirus antibody in different age groups.

Assessing the cause of in-patients pediatric diarrheal deaths: an analysis of hospital records.

Records of all the diarrheal patients up to the age of 5 years who were admitted to and died in Dr. B.C. Roy Memorial Hospital for Children, Calcutta, between January and December 1990 were analyzed. The records were reviewed to assess the relative importance of three clinical types of diarrhea (acute watery diarrhea, acute dysentery and persistent diarrhea) as the causes of mortality. Annual hospital death rates of children suffering from acute watery diarrhea, dysentery and persistent diarrhea were 13.6%, 18.2% and 25.9%, respectively. Overall death rates in dysentery (p = 0.03) and persistent diarrhea groups (p < .00001) were significantly higher than watery diarrhea group. Maximum deaths occurred among children aged between 7 and 36 months in all categories of diarrhea. Shigella infected children had higher case fatality rate. In acute watery diarrhea, 30.9% cases were assigned to associated causes of death whereas the same could be assigned to 92.6% and 93.2% cases in dysentery and persistent diarrhea group, respectively. Deaths occurred in most of the cases who had bronchopneumonia as underlying cause, septicemia as immediate cause and protein calorie malnutrition as associated cause and these were most frequently associated in patients suffering from dysentery and persistent diarrhea. Only 2.0% children suffering from acute watery diarrhea had dehydration at the time of death. Significantly, a high percentage of deaths occurred among malnourished children who suffered from dysentery (54.4%) and persistent diarrhea. These data suggest that Diarrheal Disease Control Programme should also give emphasis on management of non watery, non-dehydrating type of diarrhea with complications.

Epidemic of Vibrio cholerae 0139 in Calcutta.

As one of large outbreaks of cholera-like illness in the Indian subcontinent, Calcutta and its neighbouring areas experienced an unprecedented epidemic due to a new strain of V. cholerae non-01, designated as V. cholerae 0139 Bengal, since January 1993. This epidemic predominantly affected the adult population of Calcutta as evidenced by the hospitalization of more adults at the Infectious Disease Hospital, Calcutta (IDH), which bore the main brunt of the epidemic in and around Calcutta. During the peak of the epidemic about 180 to 300 diarrhoea patients were admitted daily at the IDH. Of the 807 patients screened, 407 were positive for V. cholerae 0139 and majority (82.8%) of the cases were > 10 yr of age. Severe dehydration was recorded in 85.5 per cent of the cases.

Clostridium difficile in antibiotic associated pediatric diarrhea.

A case control study was carried out at the medical wards of Dr. B.C. Roy Memorial Hospital for Children, Calcutta, between January and September 1989. One hundred eleven hospitalized children up to the age of 5 years, receiving antibiotics for different medical problems, developed antibiotic associated diarrhea. Isolation of Clostridium difficile as sole pathogen was very low (3.6%) from these patients. Fecal samples of 111 case matched control children were also screened for C.difficile. Only 2.7% fecal samples of control children were positive for C.difficile. All the strains of C.difficile isolated from antibiotic associated diarrhea cases showed neutralisable cytotoxin in in vitro test. In contrast none of the strains isolated from control children showed cytotoxicity. This study suggests that C.difficile is not an important pathogen related to antibiotic associated diarrhea in children at this hospital.

Acute diarrhoea caused by Vibrio mimicus in Calcutta.

Out of 539 acute diarrhoea cases studied, Vibrio mimicus was isolated as a sole pathogen in the faeces of 7 (1.3%) cases. The chief clinical presentations of the seven cases were watery diarrhoea and vomiting. Bloody diarrhoea was observed in 2 (28.5%), abdominal pain in 2 (28.57%) and fever in one (14.29) cases. All cases could be effectively treated with ORS except 3 (42.85%) cases who required IV Ringer's lactate. All V. mimicus strains isolated in the study were uniformly susceptible to tetracycline, chloramphenicol, norfloxacin and ciprofloxacin.