A laboratory-based surveillance was conducted to study the transmission of Salmonella infection in Ukraine during the period 2012-2023. The study focused on the different categories of food products, feed, and animals as the main transmission factors and tried to analyze the relationship between them. The serological profile of Salmonella was predominantly observed in samples from objects of veterinary control, including biological/pathological material from animals and biomaterials from poultry within the National Poultry Salmonellosis Control Program. The study found that the most frequently isolated serovars were S. Enteritidis (20.03%), followed by S. Typhimurium (14.76%), S. Pullorum (without biovar identification;10.71%), S. Pullorum biovar Pullorum (10.50%), S. Pullorum var. Gallinarum (6.62%), S. Choleraesuis (5.79%), S. Livingstone (2.53%), and S. Infantis (1.70%). In 2021, an isolate of monophasic S. Typhimurium was identified for the first time in pathological material from pigs. The study also found that the most frequent Salmonella-positive categories of food products in Ukraine were meat and meat products (78.16%), eggs and egg products (11.75%); dairy products (3.319%), fish products (2.71%), ready-to-eat food products (1.96%). The largest specific share of Salmonella isolates from food products and feed was S. Enteritidis, followed by serotypes such as S. Infantis, S. Typhimurium, S. Livingstone, S. Virchow, and rare serotypes such as S. Nigeria and S. Thompson. The dominance of certain serovars such as S. Enteritidis, S. Typhimurium, S. Infantis, S. Livingstone, and S. Virchow in biomaterials from sick animals indicates their primary role in the infection of food products of animal origin. Hence, a stress to enhance diagnostic and monitoring frameworks at animal herd levels. The findings of this study can be used as a basis for evidence-based epidemiology, as well as for the implementation of joint steps to improve the effectiveness of control measures against salmonellosis in each region.

Brucellosis is a serious disease that affects both animals and humans. It is caused by consuming unpasteurized dairy products that are contaminated with the Brucella bacteria. To study the pathobiology of this disease and develop preventive strategies, researchers rely on in vivo and in vitro models. A systematic literature search was conducted in January 2024, which revealed 38 studies that used these models in the previous four years. Mice were the most commonly used model for studying the disease's virulence genes, immune responses, vaccination, and treatment testing. Out of the 38 articles discussing infection models in brucellae, 6 used only in vivo models, 9 used only in vitro models, and 24 used both models. In addition, there were 32 studies with in vitro experiments, most of which utilized macrophages to study intracellular survival mechanisms and host-pathogen interactions. The studies mainly focused on B. abortus, as it had a significant impact on public and livestock health. Both in vivo and in vitro models were used to understand comprehensive intracellular mechanisms, immune responses, and treatment evaluations. However, there were several challenges in using these models, such as ethical concerns and host pathogen-specific immune responses. While both models provided important insights, the final selection choice of the model mostly depended on the research objectives, pathogen type, and availability of resources. Nevertheless, validation and understanding of these models are important to predict responses in the natural hosts