Epidemiological Profile of Cholera Outbreaks in Parts of Rural West Bengal in Last 2 Years

Background: Diarrheal outbreaks are major public health emergencies in rural West Bengal. This study was done in our hospital on diarrheal samples collected from various blocks of Bankura and Purulia district of West Bengal where on an average 10 diarrheal deaths occur annually. Objectives: The main objective of the study was: Isolation, biotyping, and serotyping of vibrio isolates, determining the antibiotic sensitivity pattern of the isolates, mapping of confirmed cholera cases for finding incidence and geo graphical location of cholera among diarrheal outbreaks in Bankura and Purulia district of West Bengal. Materials and Methods: Stool samples collected from 170 diarrheal patients in Cary Blair media along with their proper address from July 2012 to April 2014. Microbiological processing was done by conventional methods; antibiotic sensitivity test of all samples was done by Kirby Bauer disc diffusion method. Results: 170 diarrheal cases and 55 outbreaks were reported in the study period. Out of which 43 cases (25%) and 25 outbreaks (45.45%) were caused by Vibrio cholerae O1, with increased incidence in the rainy season. Among 43 cholera cases, 28 (65%) and 15 (35%) cases occurred in Bankura and Purulia, respectively, with significant clustering of cases in two blocks of Bankura. Among these strains 70% were classical, 30% were El tor biotype and all were of Ogawa serotype. Antibiotic sensitivity testing showed all isolates were sensitive to ofloxacin, norfloxacin, tetracycline, amikacin, azithromycin; 70% isolates were resistant to amoxicillin; 50% were resistant to chloramphenicol. No significant age and sex variation were noticed. Conclusion: The study reveals that in this part of West Bengal classical biotype is predominant contrary to other parts with El Tor biotype predominance. This is a significant finding for formulating future health strategy for combating diarrheal outbreaks in these areas of rural Bengal.