Human T-lymphotropic viruses types 1 and 2 (HTLV-1/2) (family Retroviridae, genus Deltaretrovirus), are due to their genomic organization capable of long persistence and latency in the human body. HTLV-1 is an oncogenic virus associated with severe diseases such as adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. HTLV-2 is not associated with the development of malignant neoplasms, but can also lead to the development of a number of severe neurological and infectious diseases. Despite the significant burden of disease associated with HTLV-1 in endemic areas, this infection remains globally neglected. Data on the prevalence of HTLV-1/2 infection in non-endemic regions are almost unavailable. Screening of blood donors for HTLV-1/2 infection markers is performed in only 50 countries worldwide. The absence of etiological therapy and specific vaccines highlights the critical importance of screening programs, preventive measures, early detection among populations at risk, and public awareness initiatives. Given the growing trends in international tourist and migration flows, enhanced epidemiological surveillance and targeted screening of high-risk groups are also essential in areas non-endemic for HTLV-1/2. The aim of this systematic review is to summarize current knowledge on the structure, genomic organization of HTLV-1 and HTLV-2, epidemiology, pathogenesis, clinical manifestations, diagnosis, treatment and prevention of HTLV-1/2-associated diseases.

The role of human herpes virus 6A and human herpes virus 6B in the pathogenesis of multiple sclerosis remains a matter of debate, largely due to the multifactorial nature of the neurological disease. This review systematizes data on the potential effect of human herpes viruses 6A and 6B on the occurrence and/or development of multiple sclerosis. The facts of the detection of laboratory diagnostic markers of beta-herpesviruses in patients with multiple sclerosis are highlighted. Hypothetical mechanisms of the pathogenesis of multiple sclerosis involving human herpes viruses 6A and 6B (molecular mimicry, incorporation of host cell proteins), including as part of a mixed infection with other viruses, are described. The mechanisms of activation of the immune system and the development of neuroinflammation under the influence of these beta-herpesviruses are considered. The main problems, unresolved issues and directions for future research in the context of the role of human herpes viruses 6A and 6B in multiple sclerosis are described.

Human papillomavirus (HPV) is one of the most common sexually transmitted pathogens. In recent years, it has been considered not only as a cause of cancer and non-cancerous growths, but also as a factor in reproductive dysfunction. In women, the virus alters the composition of the vaginal microbiota, reduces the functional activity of granulosa cells, egg maturation, and the ability of the uterine mucosa to implant and form the placenta. It also affects embryonic development and increases the risk of adverse pregnancy outcomes and premature birth.

In men, HPV alters sperm motility and morphological characteristics, and contributes to damage to genetic material, which is considered a cause of male infertility. When HPV is introduced into the sperm, it is transferred to the egg, disrupting early embryonic development.

The negative impact of HPV on the effectiveness of assisted reproductive technologies is also being studied. Infected men and women experience a reduced number of highquality embryos and the likelihood of pregnancy, as well as an increased incidence of early reproductive losses. Studying the role of HPV as a factor in subfertility, given its high prevalence, may provide additional support for widespread, gender-neutral vaccination against this infection.

Sarcopenia in people living with the human immunodeficiency virus is gradually gaining clinical significance in its own right against the background of increasing life expectancy and aging patient chores. The review examines the prevalence and risk factors for decreased muscle mass and strength in people infected with the human immunodeficiency virus, including the impact of chronic immunoactivation, metabolic disorders, comorbidities, and antiretroviral therapy. data on the role of inflammation, myosteatosis, kynurenin pathway, musculoskeletal axis disorders and environmental factors. Special attention is paid to the current diagnostic approaches, adaptation of the logic of the European Group on Sarcopenia in the Elderly of the second revision, taking into account the characteristic features of phenotypes associated with the human immunodeficiency virus. Information on clinical manifestations of sarcopenic obesity, osteosarcopenia and the combination of sarcopenia with fragility are given. Modern methods of correction are analyzed: training programs, nutritional interventions, organizational management models and possible pharmacological approaches. The data reflecting the current tasks for Russian clinical practice are presented.

Ocular involvement may be caused by various members of the family Chlamydiaceae, among which Chlamydia trachomatis plays the leading role. Chlamydial infection caused by this pathogen represents a significant medical and social challenge for contemporary public health, affecting more than 129 million people worldwide annually. The rising incidence of urogenital chlamydiosis is naturally accompanied by an increasing frequency of ocular involvement, with chlamydial conjunctivitis identified in more than 50% of patients with established urogenital infection. The absence of specific clinical symptoms, marked polymorphism of manifestations, and the pathogen’s capacity for prolonged tissue persistence considerably impede timely diagnosis. Chronic forms of infection frequently follow a latent course, remain undetected on routine examination, and lead to serious complications affecting both the reproductive system and the eye. Particular diagnostic complexity is presented by mixed infections and generalized forms of chlamydial infection involving various ocular structures, including the anterior segment. Laboratory diagnosis of chlamydial eye disease requires a comprehensive approach employing modern investigative methods, including molecular biological, immunofluorescence, immunohistochemical, and serological techniques. Diagnostic outcomes are substantially influenced by appropriate patient preparation, specimen collection technique, transport and storage conditions, and the competence of medical personnel. According to published data, pathogen verification requires the use of at least two complementary diagnostic methods to ensure the reliability of results. The rapid development of novel diagnostic technologies offers additional opportunities for improving pathogen identification, particularly in cases of atypical presentation and treatment-resistant disease. An optimal diagnostic strategy is an essential prerequisite for the timely detection of chlamydial eye disease, initiation of adequate systemic therapy, and prevention of serious complications in patients of reproductive age.

Increasing the effectiveness of intensive sepsis therapy is possible only if a personalized approach is provided with the identification of phenotypes.

The aim of the study was to evaluate the outcomes of blood purification (BP) methods and corticosteroids in the treatment of patients with severe community-acquired pneumonia (SCAP) depending on the phenotypes of sepsis.

Materials and methods: The study included 1,164 intensive care patients with SCAP in 5 multidisciplinary hospitals. The phenotype was determined using a sepsis phenotype calculator developed using the Seymour method (2019).

Results: there were a total of 814 (69.9%) patients with viral and 350 (30.1%) patients with bacterial SCAP, of which 702 (60%) were elderly and senile. In patients with viral SCAP, the α-phenotype dominated (38.5%), while the prevalence of δ was 28.4%, β -20% and γ-13.1%, respectively, p<0.001. Corticosteroids therapy in patients with α-, γ and -phenotypes of viral SCAP showed a decrease in hospital mortality, compared with patients who did not receive corticosteroids (p_a=0.014, p_γ=0.001, p_δ<0.001). An analysis of the use of BP methods in patients with viral SCAP did not reveal significant differences in outcomes. In patients with bacterial SCAP, the δ-phenotype prevailed with a frequency of 53.7%, while α 18%, β-17.7%, γ-10.6%, respectively, p<0.001. In patients with bacterial SCAP with these phenotypes, the frequency of corticosteroids use did not differ (p=0.095). Outcome analysis showed that in patients with the δ-phenotype, corticosteroids therapy was associated with unfavorable outcomes in 82.2% of cases (p< 0.001), while the use of BP techniques in 62.5% of cases with a favorable outcome of the disease (p=0.036). Early start of BP methods in the prospective recruitment group in 44 (91.7%) patients with bacterial SCAP δ-phenotype provided a favorable outcome in 63.6% of cases.

Conclusion: Identification of sepsis phenotypes in elderly and senile patients with severe community-acquired pneumonia allows for optimization of pathogenetic therapy (blood purification and corticosteroids) and improvement of disease outcomes.

Methicillin-resistant staphylococcus aureus (MRSA) nasal carriage is a significant source of infection and transmission in hospital environments. Effective infection control and antimicrobial stewardship are hampered in low-and middleincome countries by a lack of local monitoring data. This study investigated the prevalence, antimicrobial resistance pattern and genetic determinants of MRSA in patients and healthcare in two tertiary hospitals in Nigerian. A total 1, 309 nasal swabs specimens were collected from in-patients, healthcare workers and out-patients from two different tertiary hospitals. Staphylococcus aureus was identified and isolated using standard biochemical methods. The MRSA were phenotypically detected using Brilliance MRSA chromagar and cefoxitin and latter subjected to antimicrobial susceptibility testing following the standard Kirby–Bauer disk diffusion method. PCR-specific primers were used to screen for mecA and pvl genes in ten randomly selected MRSA. Out of the 1,309 nasal samples collected, 575 S. aureus representing 43.9% were isolated from the nasal samples of which 96 (17%) were MRSA, 81 from in-patients/out-patients and 15 from health care workers. The in-patients and doctors habour the highest number of MRSA, 73/81 and 8/15 respectively. All the MRSA isolates resistant to cefoxitin were also found to be resistant to tetracycline, amoxicillin, and amoxicillin-clavulanic acid. The mecA and pvl genes were detected in five of the isolates. However, pvl gene was detected in one isolate without corresponding detection of mecA gene. The high frequency of MRSA carriage among patients and healthcare personnel underscores the potential for hospital-acquired transmission and highlights the need for strengthened infection control and antibiotic stewardship in Nigerian tertiary hospitals.

The prevalence of pneumonia in generalized meningococcal disease (GMID) and its impact on the disease course remain poorly understood due to the nonspecificity of respiratory manifestations, difficulty in verifying the pathogen, and the lack of a standardized radiographic examination protocol.

The aim: to determine the incidence of lung involvement in GMID and assess its impact on the disease course and prognosis.

Materials and Methods: We analyzed the medical reports of patients with a confirmed diagnosis of GMID and chest computed tomography (CT) scans performed within 48 hours after hospitalization. Records with concomitant respiratory diseases and incomplete cases were excluded. Records were divided into groups with confirmed pneumonia and those with normal lung function. The groups were compared based on age, gender, mortality, intensive care unit (ICU) admission rate, need for respiratory support, length of hospital stay, and oxygen saturation levels. Medians, interquartile ranges, and proportions and 95% confidence intervals (CI) for qualitative variables were calculated. Differences were compared using the Mann-Whitney and Pearson chi-square tests. Differences were considered statistically significant at p ≤ 0.05.

Results. The study included 307 reports. Pneumonia was diagnosed in 54 patients (17.6%, CI 13.7-22.1%) and was characterized by a low incidence of clinical symptoms. The groups were comparable in terms of age, gender, length of hospitalization, and ICU admission rate (p>0.05). Patients with pneumonia significantly more often required prehospital respiratory support and mechanical ventilation (p<0.001). Mortality in the absence of pneumonia was 11.5% (CI 7.6-15.2), unilateral pneumonia 14.3% (CI 0-33.3), and bilateral pneumonia 42.4% (CI 25.7-60), p < 0.001.

Conclusions. Lung damage in GMID occurs in 13-22% of patients and develops concurrently with other GMID symptoms. The severity of the condition and prognosis correlate with the presence of pneumonia and the extent of lung damage. Due to the absence of respiratory symptoms in most cases, all patients with GMID should undergo lung imaging, and if lung consolidation is detected, more intensive treatment should be determined.

Objective. To conduct a comprehensive analysis of clinical and epidemiological features, laboratory characteristics, and the effectiveness of organizational decisions during a large-scale outbreak of aseptic meningitis in 2023.

Materials and methods. A retrospective analysis of 880 cases of meningitis hospitalized in a regional infectious disease hospital during the epidemic rise was performed. The study cohort included 754 children (85.7%) and 126 adults (14.3%). Etiology verification was performed by PCR. Cerebrospinal fluid (CSF) parameters, duration of hospitalization, and outcomes were evaluated.

Results. The outbreak was characterized by an “explosive” increase in incidence caused by the combined circulation of Coxsackie A6 and ECHO 30 enteroviruses (82.2% of verified cases). It was found that in 24% of cases in children, neutrophilic pleocytosis was recorded at the onset of the disease, mimicking the bacterial nature of inflammation. This required a revision of diagnostic algorithms with the introduction of repeated lumbar punctures to monitor sanitation. Adult patients were characterized by a longer hospital stay (17–19 days versus 13–14 in children) and required antibiotics 2.5 times more often. The use of tactics of early discharge of patients with residual pleocytosis (<30 cells/µl) allowed coping with the peak load. Mortality in the study group was 0%.

Conclusion. Neutrophilic pleocytosis is a frequent variant of the onset of enteroviral meningitis (CVA6/ECHO30), which requires alertness in differential diagnosis. The introduction of dynamic cerebrospinal fluid monitoring allows minimizing antibacterial therapy safely and optimizing bed turnover.

Aim: To clinically characterize non-invasive forms of Haemophilus influenzae infection caused by type b (Hib) and non-typeable strains (NTHi) strains in children.

Materials and methods: We analyzed medical records of children hospitalized at Children’s City Clinical Hospital No. 5 named after N.F. Filatov (Saint Petersburg) from 2002 to 2023. The study included 62 patients (aged 1 month to 16 years) with verified non-invasive forms of H.influenzae infection: 25 children with Hib infection and 37 with NTHi infection. Verification was performed using bacteriological methods (cultures of nasopharyngeal mucus, sputum, and discharge from ENT foci).

Results: In some patients, the process was limited to acute respiratory infection (Hib: 8%; NTHi: 21%). Pneumonia subsequently developed (Hib: 32%; NTHi: 30%) or purulent ENT foci (Hib: 60%; NTHi: 49%). Pneumonia predominantly affected children under 24 months (79%), regardless of etiology; acute respiratory failure of grades I–III was recorded in 84% of patients with pneumonia. Among ENT focal infections, pansinusitis predominated (42%); mastoiditis and otoantritis were identified in 2 cases of Hib infection. Most patients (76%) with ENT involvement were hospitalized between days 7 and 21 of illness. No significant age differences were found between the Hib and NTHi groups. Prehospital targeted therapy was administered to 10 of 62 children; penicillins were ineffective in most cases, whereas II-III generation cephalosporins were effective.

Conclusion: Forms of H.influenzae infection caused by Hib and NTHi are characterized by similar manifestations, an indolent course with moderate systemic toxicity, and involvement of young children. Late presentation and diagnosis, along with inadequate prehospital antibiotic therapy, lead to severe disease progression and risk of progression to invasive disease.

The problem of brucellosis at the current stage determines the need to study the pathophysiological features of the infection, including the assessment of the significance of changes in the functions of platelets, vascular endothelium, and the immune system in the pathogenesis of the disease.

The aim of the study is to determine the significance of inflammation factors, hemostasis, and indicators of endothelial dysfunction in the development of clinical and pathophysiological changes in acute brucellosis.

Materials and methods of the study: 78 patients aged 19 to 68 with acute brucellosis were under observation during inpatient treatment. All patients underwent a comprehensive clinical and laboratory examination, including testing for inflammatory and hemostatic markers.

Results: In patients with acute brucellosis, thrombocytopathy is observed despite normal platelet counts. Lipid A, a component of lipopolysaccharide (LPS) from Brucella, interacts with the platelet membrane, inhibiting activation and aggregation processes. The structural features of lipid A in Brucella LPS limit its ability to actively recruit Hageman factor (XII) into the hemostatic cascade, thereby reducing the level of inflammatory reactions. Relatively long-term persistence of Brucella in the body leads to mild (moderate) inflammation and is accompanied by a hemostatic balance between the coagulation and anticoagulation systems of the blood, indicating a sufficient adaptive response that prevents the development of thrombotic complications. An increase in the level of endothelial dysfunction indicators (due to the influence of inflammatory mediators released by platelets), acute phase proteins of inflammation, and the appearance of an Mpeak in the region of γ-globulins against the background of dysproteinemia were shown.

Conclusion: The pathogenesis of acute brucellosis has been determined, including the formation of a systemic inflammatory response against a background of changes in the blood coagulation system and endothelial dysfunction caused by the action of Brucella LPS.

The aim of this study was to analyze of some TRIM5 gene variants in HIV-infected individuals

Materials and methods. The analysis of the rs10838525 (R136Q) and rs3740996 (H43Y) variants of the TRIM5 gene was performed in groups of HIV-infected individuals with virological failure of antiretroviral therapy (n = 378) and control group (n = 319) (individuals without acute or chronic infectious and somatic diseases at the time of examination) from the Northwestern region of Russia. Genotyping was carried out by PCR followed by sequencing. Statistical analysis included testing for Hardy-Weinberg equilibrium, assessment of associations under three inheritance models (dominant, recessive, additive) with calculation of odds ratios (OR) and 95% confidence intervals (CI), as well as haplotype analysis.

Results. Statistically significant differences in the distribution of genotypes between the groups were identified for the specified variants (p < 0.0001). The 136R allele (rs10838525) was associated with an increased risk of HIV infection (additive OR = 1.67; 95% CI 1.33–2.10), whereas the 43Y allele (rs3740996) demonstrated a protective effect (additive OR = 0.55; 95% CI 0.44–0.70; p < 0.0001). Haplotype analysis confirmed the divergence of effects: the R-H haplotype was associated with an increased risk (OR = 1.55; p = 0.0047), while the Q-Y haplotype was associated with a reduced risk (OR = 0.49; p < 0.0001).

Conclusion. This study establishes that the R136Q and H43Y variants of the TRIM5 gene are significant genetic factors associated with HIV infection in the Russian population, exerting opposing effects on susceptibility. These findings underscore the importance of accounting for population-specific genetic architecture and highlight the need for further investigation into the role of TRIM family proteins in HIV pathogenesis, with careful consideration of regional variations.

Postmortem diagnostics of HIV infection, hepatitis B, C and syphilis in forensic medical examination institutions can provide access to the study of prevalence in key population groups, improve the quality of statistical data, increase the validity of forensic medical diagnoses and map biological risks. This potential, however, has not been realized today.

The purpose of research was to assess the prevalence of HIV infection, hepatitis B and C, syphilis based on the results of a study of blood serum taken from corpses admitted to a forensic medical examination institution; assessment and analysis of the comorbidity level of socially significant infections in the study population.

The research materials included blood taken from corpses admitted to the State Budgetary Healthcare Institution of the Tyumen Region “Regional Bureau of Forensic Medical Examination” in accordance with the current sanitary rules and regulations 3.3681-31.

Research methods. Markers of HIV infection, viral hepatitis B, C and syphilis were determined using commercial test systems approved for use in Russia. A statistical analysis was performed based on the results.

The results of research. Postmortem examination of blood serum from deceased individuals revealed serological markers of one or more of the above infections in 35.8% of cases. According to the study results, the chance of detecting antibodies to the hepatitis C virus in corpses with HIV infection was 12.96 times higher than in corpses without HIV infection, and the chance of detecting serological markers of two viral hepatitis infections simultaneously was 7.26 times higher. The presence of any marker of a socially significant infection significantly increases the likelihood of detecting another marker. The discussion of the obtained results includes a comparison of the obtained results with regional data and the results of similar foreign studies, and a significant limitation of the study, namely, the use of test systems that are not validated for studying cadaveric blood, is discussed in detail.

Conclusion. Diagnostics of HIV infection, hepatitis B and C, syphilis during forensic autopsies allows access to testing in key population groups. Taking into account the data obtained in the course of our study, in order to improve the epidemiological surveillance system and improve preventive measures, the authors propose the introduction of expanded laboratory postmortem diagnostics of HIV infection, hepatitis B, C and syphilis during autopsies, provided that adequate algorithms for testing cadaveric blood are developed, taking into account the diagnostic sensitivity of test systems used in postmortem diagnostics of infections.

Aim: to assess the state of humoral immunity against measles and factors influencing its intensity among staff of an infectious diseases center.

Materials and methods: the study included 463 employees of the Federal Scientific and Clinical Center for Infectious Diseases. The concentration of specific immunoglobulin G against measles virus in blood serum was determined by enzyme-linked immunosorbent assay. An antibody level of 0.18 international units per milliliter and above was considered protective. Data on age, professional status, vaccination history, and previous measles infection were collected. Student’s t-test and the chi-square test were used for statistical analysis.

Results: a non-protective level of measles antibodies was found in 12.9% of the examined staff. The highest proportion of seronegative individuals was detected in the 20-37 age group: 22.5% among medical and 30% among nonmedical personnel. In the group over 57 years old, this rate was 1-4%. No statistically significant differences were found in antibody levels between medical and non-medical workers, nor between individuals in direct contact with infectious patients and other staff. Among employees with documented two-dose and three-dose vaccination, the proportion of individuals without protective immunity was 17-18.5%. Administration of an additional (booster) vaccine dose to staff with non-protective titers after a complete vaccination course led to seroconversion or a significant increase in antibody levels in 90.9% of cases.

Conclusion: a significant proportion of staff at an infectious diseases center, especially young individuals, lack protective immunity against measles despite prior vaccination. Professional activity in an infectious diseases hospital setting is not a significant booster factor. The results justify the need to implement regular serological monitoring of measles immunity among all personnel, followed by revaccination of seronegative individuals.

Aim: to study the clinical and epidemiological features of acute respiratory infections of the upper respiratory tract in individuals from an organized military unit at the initial stages of its formation in order to improve the quality of antiepidemic protection.

Research objectives: to determine the structure of the causative agents of ARI of the upper respiratory tract, to assess the frequency of clinical symptoms in various etiological variants of the disease, to conduct a comparative analysis of clinical manifestations, and to propose clinical guidelines for the differential etiological diagnosis of acute respiratory infections of the upper respiratory tract at the initial stages of the formation of an organized military unit.

Materials and methods: clinical, epidemiological, and laboratory data of 287 patients who sought medical care for upper respiratory tract infections were analyzed. The etiology of the disease was determined using multiplex PCR and classical bacteriological studies, and the results were used to form groups based on the type of isolated pathogens. The frequencies of clinical symptoms were calculated for each group.

Results: 221 cases (77.0%) were monoinfections, and 66 cases (23.0%) were co-infections. The most common pathogens were rhinovirus (28.6%) and influenza B virus (11.5%). Rhinovirus infection was characterized by a predominance of catarrhal syndrome (rhinorrhea 75.6±4.7%, pharyngitis 65.9±5.1%) with a low frequency of fever (12.2±3.7%). In cases of influenza B and adenovirus infections, fever (36.4±8.8% and 40.0±10.7%, respectively) and cough (78.8±7.1% and 80.0±8.9%) were more common.

Metapneumovirus and respiratory syncytial virus were manifested mainly by cough. Seasonal coronaviruses were mild infections with rhinitis and pharyngitis. SARS-CoV-2 infection had a variable clinical picture without specific signs. Diseases caused by bacterial agents were characterized by more pronounced inflammatory manifestations: Streptococcus pyogenes — typical tonsillitis without catarrhal symptoms, Staphylococcus aureus — intoxication and a purulent component. In co-infections, a combination of symptoms was observed.

Conclusions: the clinical manifestations of ARI URT in members of organized groups may be characterized by certain symptom complexes, due to the etiology of the disease, which allows them to be used for preliminary differential diagnosis in conditions of limited laboratory availability.

Objective: To identify current epidemiological characteristics of acute gastrointestinal infections (AGI) among patients 18 years and older hospitalized in an infectious diseases hospital.

Materials and Methods: Data from Form No. 60/u of the «Journal of Infectious Diseases» was analyzed for patients hospitalized with AGI at the Clinical Infectious Diseases Hospital named after S.P. Botkin in St. Petersburg from January 1, 2022, to October 31, 2025. Etiological determination was performed using polymerase chain reaction, serology (indirect hemagglutination assay), and bacteriology. Microsoft Excel was used to process the obtained data.

Results: Since 2022, an increase in the number of hospitalized adult patients with AGI of established etiology has been observed. In the etiological structure of acute intestinal infections, Norovirus, Salmonella spp., Campylobacter spp., and Rotavirus account for 73.9% to 80.4% of cases. Since December 2023, a dramatic increase in the number of patients admitted with acute intestinal infections of norovirus etiology has been detected; in 2025, their share reached 39%. An increase in the proportion of AGI of mixed etiology was detected from 4.5% in 2022 to 9.4% in 2024, while combinations of norovirus with other microorganisms accounted for 60.3% of associations. In addition to typical seasonality, increases in the number of patients with acute intestinal infections of viral etiology were observed in the summer months. An inverse correlation (r = -0.89) was observed between the number of admissions and the age of patients. The maximum number of hospitalizations was observed among individuals aged 18-19 in 2022-2023 and 19-23-year-olds in 2024-2025. More than 70% of those hospitalized with acute intestinal infections caused by campylobacter and norovirus were under 40 years of age, while the age distribution for rotavirus etiology was uniform, and for Clostridioides difficile, patients over 60 years of age predominated.

Conclusion: An increase in hospitalizations of patients with AGI, whose etiology was subsequently elucidated, has been identified. An inverse relationship between patient age and hospitalization rate is observed. The main causative agents among young adults are Campylobacter and Norovirus. When collecting the epidemiological history, it is necessary to detail information on the consumption of ready-to-eat meals, including the public catering establishments where they were purchased.

Pneumococcal infection (Streptococcus pneumoniae) remains one of the leading causes of severe communityacquired pneumonia and sepsis, which can rapidly lead to multiple organ failure and death even in individuals without significant comorbidities. A hallmark of severe sepsis is the early development of immune dysregulation with profound T-cell lymphopenia, which substantially worsens the prognosis. Modern intensive care, including extracorporeal blood purification when indicated, may contribute to a more favorable disease course. The article presents a clinical case of a 33-year-old patient without a relevant premorbid background, admitted to the St. Petersburg State Medical Institution “Clinical Infectious Diseases Hospital named after S.P. Botkin” with the diagnosis of Community-acquired pneumonia caused by Streptococcus pneumoniae, severe course, complicated by severe sepsis (SOFA >4).

The article presents two clinical observations demonstrating the persistent risk of hepatocellular carcinoma in patients with chronic hepatitis C after achieving sustained virological response. In the first case, a patient from the Republic of Tyva with pre-existing liver cirrhosis (F4) developed hepatocellular carcinoma after long-term virus persistence and late sustained virological response. Fibrosis regression (F4–F2) and normal alpha-fetoprotein levels contributed to the lesions being interpreted as adenomas, leading to a three-year delay in diagnosis verification. In the second case, a patient from St. Petersburg with HIV/HCV coinfection developed hepatocellular carcinoma one year after achieving sustained virological response. The final diagnosis (hepatocellular carcinoma) was established only at autopsy, whereas cholangiocarcinoma had been suspected during life. Portal vein tumor thrombosis was identified, which was complicated by fatal bleeding from esophageal varices. These observations indicate the need for lifelong follow-up in patients with chronic hepatitis C, especially in those with pre-existing cirrhosis and HIV coinfection. Any newly detected hypervascular liver lesion in this patient category should be considered potentially malignant until proven otherwise.