Epidemiological characteristics of Salmonella infection in Yuyao, Zhejiang, 2015–2020

  Objective  To understand the seasonality, population distribution and pathogenic food of salmonella infection in Yuyao from 2015 to 2020, and provide scientific evidence for the prevention and control of salmonellosis.

  Methods   A total of 2104 stool samples or anal swabs samples were collected from the patients with foodborne diseases in Yuyao Maternity and Child Healthcare Center (a sentinel hospital) from 2015 to 2020 for the culture and isolation of Salmonella , and the isolated Salmonella strains were serotyped. Circular distribution method was used to analyze the seasonality of Salmonella infection. The gender, age and population distribution of Salmonella infection were descripted, and pathogenic food were identified.

  Results  A total of 234 Salmonella strains were detected, the averages annual positive rate was 11.12%. The Salmonella detected belonged to 36 serotypes. Salmonella Typhimurium(38.89%) and Salmonella Enteritidis (11.97%) were predominant. Circular distribution analysis indicated that the annual detection rate peaked during May-July and high detection lasted to September. The peak day was 15th July from the analysis of circular distribution.The detection rate was highest in 1–5 years old group (18.49%), followed by 0–1 year old group (16.51%), 5–10 years old groups (10.64%). The detection rates of Salmonella were high in eggs or egg product, grain or grain product, fruit or fruit product (P<0.05).

  Conclusion  The detection rates of Salmonella in food was high in Yuyao. The seasonality of Salmonella detection was obvious. Infants and preschool aged children were the susceptible population to Salmonella infection. Salmonella was detected in all main foods. It is necessary to strengthen the prevention of food contamination by Salmonella.