Bartonella are known to be important causes of zooanthroponotic diseases. The range of human infection varies from mild lymphadenopathy and asymptomatic bacteremia to life-threatening systemic disease in immunocompromised patients. Microbiological improvements in isolation methods and PCR amplification of organism-specific DNA sequences have resulted in a dramatic increase in reports describing human patients with bartonellosis. Nevertheless, clearly and successful isolation of Bartonella spp. from bacteremic animals and human patients remains an ongoing challenge. Technology of experimental bartonellosis due to intraperitoneal introduction of biological material samples containing causative agents to laboratory animals is presented in the article. White nonlinear mice with the artificially cyclophosphamide formed immunodeficient state may be used as an experimental model for further investigation of the biological alterations responsible for angiomatosis. On the other hand, we believe that this new method will enhance the diagnostic sensitivity and specificity needed to achieve a diagnosis of bartonellosis.

Influenza viruses, in particular A ‒ A(H3N2) and A(H1N1)pdm09, as well as influenza B virus, mainly (98%) of the B/Victoria line, continue to circulate during the current epidemic season. The level of influenza vaccination remains low, about 0.6% of the population of Ukraine, and among occupational and epidemiological risk groups ‒ 22.8%, according to the Public Health Centre of the Ministry of Health of Ukraine. In the COVID-19 pandemic, simultaneous circulation of influenza viruses and SARS-CoV-2 can lead to difficulties in differential diagnosis and treatment. Comparison of clinical and laboratory features of severe influenza complicated by pneumonia caused by pandemic influenza virus A(H1N1)pdm09 in the epidemic season of 2015/2016 Kharkiv RCIDH with COVID-19 on clinical and laboratory data was the aim of the work. Patients and research methods. The analysis of clinical symptoms and laboratory examination data of 19 patients with influenza complicated by community-acquired pneumonia of clinical group IV who were treated at the Kharkiv Regional Hospital and their comparison with those of patients with COVID-19 according to the literature. Results and discussion. Among the studied patients, men predominated ‒ 12 persons (63.2%) aged 50.68±11.95 years. The predominant number had concomitant diseases. At the beginning of the disease, moderate weakness, headache, fever, minor catarrhal phenomena and, as a result, delayed hospitalization prevailed. From 3‒4 days of the disease the condition significantly worsened, shortness of breath and cyanosis joined. Typical initial symptoms of COVID-19 are fever of varying degrees (73%), unproductive cough (59%) and shortness of breath or shortness of breath. Conclusions. In patients with COVID-19 and severe influenza, a more acute onset of the disease was reported, with moderate weakness, headache and fever up to 38°C and symptoms of pharyngitis. Influenza patients often show a delay in seeking medical attention and hospitalization for 6.21±1.46 days of illness. The severity of the disease in influenza is due to the accession of community-acquired pneumonia, in contrast to COVID-19, where the typical features are diffuse, mostly subpleural lung affection. Vaccination of people at risk before the start of the epidemic season is necessary to prevent severe complications of influenza caused by the pandemic virus A(H1N1)pdm09 in the context of the COVID-19 pandemic. Keywords: influenza, pneumonia, COVID-19, diagnosis.