Prediction of cross-border spread of the COVID-19 pandemic: A predictive model for imported cases outside China.

The COVID-19 pandemic has been present globally for more than three years, and cross-border transmission has played an important role in its spread. Currently, most predictions of COVID-19 spread are limited to a country (or a region), and models for cross-border transmission risk assessment remain lacking. Information on imported COVID-19 cases reported from March 2020 to June 2022 was collected from the National Health Commission of China, and COVID-19 epidemic data of the countries of origin of the imported cases were collected on data websites such as WHO and Our World in Data. It is proposed to establish a prediction model suitable for the prevention and control of overseas importation of COVID-19. Firstly, the SIR model was used to fit the epidemic infection status of the countries where the cases were exported, and most of the r2 values of the fitted curves obtained were above 0.75, which indicated that the SIR model could well fit different countries and the infection status of the region. After fitting the epidemic infection status data of overseas exporting countries, on this basis, a SIR-multiple linear regression overseas import risk prediction combination model was established, which can predict the risk of overseas case importation, and the established overseas import risk model overall P <0.05, the adjusted R2 = 0.7, indicating that the SIR-multivariate linear regression overseas import risk prediction combination model can obtain better prediction results. Our model effectively estimates the risk of imported cases of COVID-19 from abroad.

Analysis of 90 Listeria monocytogenes contaminated in poultry and livestock meat through whole-genome sequencing.

Listeria monocytogenes is a food-borne pathogen that can cause human listeriosis. The main cause of L.monocytogenes poisoning is the consumption of contaminated or processed foods, of which meat is the main one. At present, it is not clear whether the listeria contaminated in different meatis genetically diverse. In this study, a total of 90 L.monocytogenes isolates including 28 isolates in livestock meat and 62 isolates in poultry meat were obtained from chicken, duck, pork, and beef respectively in Beijing. And whole-genome sequencing (WGS) based analysis was performed to investigate the genetic diversity of L.monocytogenes between poultry and livestock meat isolates. As a result, we found the prevalence of the multilocus sequence typing (MLST)-derived clonal complexes (CCs) were quite different between two different types of meat. The number of resistance genes and virulence genes in most of the L.monocytogenes isolated from the four meat species were close, but the sequences of eight resistance genes and 19 virulence genes were significantly varied between poultry meat and livestock meat. The phylogenetic and collinear analysis of these isolates revealed the isolates in the same meat have a similar genome. These results showed that the genetic variation of L.monocytogenes in livestock and poultry meat were significantly different isolates.