Epidemiological characterization of sapovirus gastroenteritis aggregation in a kindergarten in Jinshan District， Shanghai

ObjectiveTo analyze the epidemiological characteristics of an aggregational gastroenteritis and determine the genotypes of sapovirus， and to provide scientific basis for formulating effective control strategies.

MethodsUnified case definition， active case search and descriptive epidemiology were used to analyze the epidemic. Feces or anal swabs of untreated students， teachers， canteen staff as well as canteen environment samples were collected. Norovirus and sapovirus nucleic acid tests were conducted by real-time fluorescent RT-PCR， and sapovirus nucleic acid was amplified by conventional RT-PCR. The gene region of capsid protein was analyzed by MEGA7.0 software and phylogenetic tree was constructed.

ResultsA total of 12 cases were reported in the epidemic， and the incidence rate was 44.44%. All reported cases， with vomiting symptoms， were found in the same class. The epidemic showed a point-based outbreak. The first case became the source of infection in class， and the epidemic lasted for 8 days. Real-time fluorescent RT-PCR assay confirmed that five children's feces were positive for sapovirus nucleic acid， and the first-episode children's feces were positive for sapovirus and GII norovirus nucleic acid. Sequence alignment result showed that the sapovirus strains belonged to GI.1 type with homologous genes.

ConclusionBased on the clinical manifestations， field epidemiological investigation and laboratory test results， we confirm that the first case of the epidemic in class is caused by GI.1 sapovirus infection. The epidemic is effectively controlled by comprehensive measures such as case isolation and disinfection.