Epidemiological characteristics of cholera in Shanghai city, 2008 – 2017

Objective To examine the incidence and risk factors of cholera and drug resistance of isolated Vibrio cholerae strains in Shanghai city.

Methods The collected data for the study included all registered cholera cases and their case survey reports, the isolatios of pathogens from drinking water, food and environment specimens at 19 monitoring sites, and the results of drug resistance to 12 antibiotics of the isolated Vibrio cholerae strains during the period from 2008 to 2017 in Shanghai city. Paper diffusion method (Kirby-Bauer, K-B) was used in drug resistance test.

Results The majority of the cholera cases reported during the 10-year period were local residents and 90.48% of cases dwelled in suburb regions of Shanghai. The main clinical manifestations of the cases were diarrhea and vomiting, with 61.9% of the cases reporting diarrhea of 10 times or more and 45.45% reporting vomiting of 3 times or more. Almost all the cases reported suspicious incidence related-dietary history during one week before the onset of the disease, of which 76.19% reported the history of dinner party. Vibrio cholera contamination to water, food and external environment were at a very low level based on the monitoring data and it was consistent with the low incidence of cholera during the period. All isolated Vibrio cholera strains were sensitive to ceftriaxone and the observed highest resistance rate (74.07%) of the isolated strains was to nudic acid.

Conclusion The cholera incidence was at a low level in Shanghai city from 2008 to 2017. Food contamination and the history of dinner party one week before the disease incidence were main risk factors of cholera epidemic. Antibiotic resistance is prevalent for Vibrio cholera strains isolated from monitoring specimens in the city.