Ticks are recognized as the main vectors and reservoirs of spotted fever group rickettsiae. We searched for the most prevalent Rickettsia spp. in Poland and found R. slovaca and R. helvetica bacteria in ticks in southern and central Poland; R. raoulti was found in ticks in all parts of Poland.

S. pneumoniae, in particular serotype 6B and 19A, is the most common etiologic agent of PPE/PE in Polish children. The use of PCR significantly improves pathogen identification in pleural fluid.

To investigate the role of B. henselae in patients with symptoms suggesting neuroborreliosis, serum and cerebrospinal fluid samples were tested with serological and PCR methods. Among 17 examined patients, in 12 cases Borrelia burgdorferi infections were detected, in 1 case Bartonella henselae infection was ascertained, and in two patients mixed B. burgdorferi and B. henselae infections were found. These results indicate that mixed infections should be taken into consideration in establishing diagnosis of neurological disorders. Further study of this conclusion is needed.

Since the SARS-CoV-2 outbreak, many countries have introduced measures to limit the transmission. The data based on ICD-10 codes of lower respiratory tract infections and microbiological analysis of respiratory and gastrointestinal infections were collected. The retrospective five-year analysis of the medical records revealed a substantial decrease in respiratory tract infections during the pandemic year (from April 2020 to March 2021). We noted an 81% decline in the LRTI-associated hospital admissions based on the ICD-10 analysis (from a mean of 1170 admissions per year in the previous four years to 225 admissions between April 2020 through March 2021). According to microbiological analysis, there were 100%, 99%, 87%, and 47% drops in influenza virus, respiratory syncytial virus, rotavirus, and norovirus cases reported respectively during the pandemic season until April 2021 in comparison to pre-pandemic years. However, the prevalence of gastrointestinal bacterial infections was stable. Moreover, in August 2021, an unexpected rise in RSV-positive cases was observed. The measures applied during the COVID-19 pandemic turned out to be effective but also had a substantial contribution to the so-far stable epidemiological situation of seasonal infections.

The presence of antibodies to Rickettsia conorii, R. helvetica, R. felis, R. slovaca, R. sibirica, and R. massiliae in sera of 129 forest workers from northeastern and southern Poland was assayed by indirect immunofluorescence. Previous environmental studies revealed presence of spotted fever group (SFG) rickettsiae in ticks collected from these areas. Additionally, the workers were examinated for the presence of antibodies specific to other tick-borne bacteria: Anaplasma phagocytophilum, Bartonella spp., and B. burgdorferi. The results of the studies have shown the presence of specific SFG rickettsiae antibodies in 14.7% of tested forest workers, among them 78.9% had species-specific antibodies to R. massiliae. Contrary to previous detection R. helvetica and R. slovaca in ticks collected in the environment of the examined area, no species-specific antibodies to these species were detected in studied workers. Antibodies to B. burgdorferi (44%) were found in forest workers more often than antibodies to other tested pathogens. B. burgdorferi was also the main component of coinfections. The most frequent confirmed serologically coinfections were simultaneous infections with B. burgdorferi and Bartonella spp. found in 10% of tested individuals. So far, SFG rickettsiae infections have not been diagnosed in Poland; however, the presence of the bacteria in ticks and presence of specific antibodies in humans exposed to arthropods show the need for monitoring the situation. The list of tick-borne pathogens is increasing, but knowledge about the possibility of humans acquiring multipathogens infections after tick bite still needs evaluation.