Epidemiological characteristics of typhoid and paratyphoid fever in coastal areas of high incidence during 1950-2017

ObjectiveTo investigate the long-term trends and epidemiological characteristics of typhoid and paratyphoid in the eastern coastal areas during the past 67 years.

MethodsRetrospective analyses were used to systematically analyze the epidemic data and outbreak data on typhoid and paratyphoid in Ningbo from 1950 to 2017.PASW Statistics 20.0 software was used to calculate the correlation rate and to test the non-linear regression model fitting.

ResultsA total of 29 583 cases of typhoid and paratyphoid were reported from 1950 to 2017 in Ningbo.The cases were mainly adults aged 20-50 years old with obvious regional agglomeration.The onset was periodic with peak incidence in winter and spring, which was significantly different from the other parts of the country with peak incidence in autumn.Outbreaks were mainly based on water and food borne transmission.

ConclusionNingbo is in areas with historic high morbidity of typhoid and paratyphoid.The risk factors are associated with the pollution of water sources and the habits of eating half raw seafood.Strengthening the hygiene supervision of shellfish and the management of water and excreta, conducting health education, and changing the habits of eating half raw seafood are the main measures to control the incidence of typhoid and paratyphoid.