The Impact of Cytokines on Coagulation Profile in COVID-19 Patients: Controlled for Socio-Demographic, Clinical, and Laboratory Parameters.

Background: Severe coagulation abnormalities are common in patients with COVID-19 infection. We aimed to investigate the relationship between pro-inflammatory cytokines and coagulation parameters concerning socio-demographic, clinical, and laboratory characteristics. Methods: Our study included patients hospitalized during the second wave of COVID-19 in the Republic of Serbia. We collected socio-demographic, clinical, and blood-sample data for all patients. Cytokine levels were measured using flow cytometry. Results: We analyzed data from 113 COVID-19 patients with an average age of 58.15 years, of whom 79 (69.9%) were male. Longer duration of COVID-19 symptoms before hospitalization (B = 69.672; p = 0.002) and use of meropenem (B = 1237.220; p = 0.014) were predictive of higher D-dimer values. Among cytokines, higher IL-5 values significantly predicted higher INR values (B = 0.152; p = 0.040) and longer prothrombin times (B = 0.412; p = 0.043), and higher IL-6 (B = 0.137; p = 0.003) predicted longer prothrombin times. Lower IL-17F concentrations at admission (B = 0.024; p = 0.050) were predictive of higher INR values, and lower IFN-γ values (B = -0.306; p = 0.017) were predictive of higher aPTT values. Conclusions: Our findings indicate a significant correlation between pro-inflammatory cytokines and coagulation-related parameters. Factors such as the patient's level of education, gender, oxygen-therapy use, symptom duration before hospitalization, meropenem use, and serum concentrations of IL-5, IL-6, IL-17F, and IFN-γ were associated with worse coagulation-related parameters.

Clostridioides difficile ribotype distribution in a large teaching hospital in Serbia.

BACKGROUND: The global epidemic of nosocomial diarrhea caused by Clostridioides (Clostridium) difficile started in 2000, with high mortality rates and emergence of a new hypervirulent strain NAP1/BI/027. The aim of this study was to assess the presence of ribotype 027 and other C. difficile ribotypes in a Serbian University Hospital, compare the temporal variability of ribotypes 3 years apart, as well as to compare clinical, demographic and laboratory characteristics and disease outcome among patients infected with 027 and non-027 ribotype. This was a prospective observational cohort study addressing 4-month intervals during 2014/2015 and 2017/2018. RESULTS: Ribotyping was performed in 64 non-duplicate C. difficile strains. Ribotype 027 was the most prevalent, and was detected in 53 (82.8%) patients (43/45 and 10/19 patients in 2014-2015 and 2017/2018, respectively). Other detected ribotypes were 001/072 in 4 (6.3%), 002 in 4 (6.3%), 014/020 in 2 (3.1%) and 176 in 1 (1.5%) patient. The percentage of the patients infected with ribotype 027 significantly decreased during the 3-year period, from 95.6 to 52.6% (p < 0.001). Ribotype 027 infection was associated with fluoroquinolone treatment more frequently than infection with other ribotypes [33 (62.3%) vs. 2 (18.2%), p = 0.010)]. A severe C. difficile infection was diagnosed more often in patients with the detected ribotype 027 compared to those infected with non-027 ribotypes (p = 0.006). No significant difference in the mortality and recurrence rates was found between the patients infected with ribotype 027 and those infected with other ribotypes [10/53 (18.8%) vs. 2/11 (18.2%), p = 0.708, and 10/35 (28.6%) vs. 0/2 (0%), p = 1.000, respectively]. CONCLUSION: Clostridium difficile ribotype 027 was the most prevalent ribotype among patients in a large Serbian hospital, but there is a clear decreasing trend.

Micro-elimination of HCV as a possible therapeutic strategy: our experience and a review of literature.

BACKGROUND: Serbia has an intermediate estimated prevalence of chronic hepatitis C (CHC) infection, approximately 1.13%, with hepatitis C remaining one of the leading causes of liver-related morbidity and mortality in Serbia with impaired quality of life and overwhelming cost of treating its complications As the availability of new treatment options and resources for screening remains limited, micro-elimination of CHC becomes a top priority. METHODS: Review of the available published data related to the clinical and epidemiological situation of the hepatitis C infection in Serbia, including the unpublished data from the databases of four major reference centres in Serbia (Clinical Center Serbia, Clinical Center Nis, Clinical Center Vojvodina and Clinical Center Kragujevac). RESULTS: Currently in Serbia, micro-elimination appears to be realistic in the patients with haemophilia, who represent a small, well-defined subpopulation, under constant monitoring by the healthcare system. Other feasible targets for micro-elimination of CHC infection in Serbia are patients on hemodialysis, prisoners and people who inject drugs. CONCLUSIONS: Micro-elimination is feasible in Serbia, especially in the subpopulation of patients with haemophilia. This may represent an initial step towards achieving the WHO objective to eliminate hepatitis C infection by 2030.

Significance of UGT1A1*28 Genotype in Patients with Advanced Liver Injury Caused By Chronic Hepatitis C.

BACKGROUND: Chronic hepatitis C (CHC) is a significant cause of liver related morbidity and mortality worldwide. The role of genetics in the host response to hepatitis C virus is not elucidated. Genetic variations in UGT1A1 gene are the most common cause of hereditary unconjugated hyperbilirubinemia-Gilbert syndrome. This is the first study investigating the association of UGT1A1 TA repeats promoter genotypes with the degree of liver injury, viremia and biochemical markers in CHC patients with advanced liver injury and late virological relapse. METHODS: Genetic testing of UGT1A1 TA repeats promoter genotypes was performed in 42 CHC patients with advanced fibrosis and cirrhosis who achieved sustained virological response and 42 healthy blood donors. CHC patients were evaluated for clinical findings, laboratory tests and imaging. RESULTS: UGT1A1*28 genotype (7/7 TA repeats) was observed in 23.8% CHC patients and 16.7% healthy controls with no significant difference in genotype frequencies (p=0.49). Pretreatment levels of ferritin and bilirubin were associated with the presence of UGT1A1*28 genotype, indicating its potential as a predictive marker. However, in our study, there was no correlation of UGT1A1*28 genotype with the degree of fibrosis or viremia. During antiviral treatment, dose reductions and treatment interruptions, as well as treatment success and occurrence of late virological relapse were not related to the presence of UGT1A1*28 genotype in CHC patients with severe liver injury. CONCLUSIONS: Frequencies of UGT1A1*28 genotype are high in both Serbian CHC patients and healthy subjects. The presence of UGT1A1*28 genotype was not associated with ribavirin-related adverse effects and had no effect on long term outcome in CHC patients.

Serological status of childbearing-aged women for Toxoplasma gondii and cytomegalovirus in northern Kosovo and Metohija.

INTRODUCTION: Toxoplasma gondii and cytomegalovirus (CMV) are pathogens associated with congenital anomalies. METHODS: Serum was collected from 79 reproductive-age women and tested for IgM and IgG antibodies to T. gondii and CMV. RESULTS: Seropositivity for T. gondii was detected in 24.1% of women and CMV in 96.2%. High seropositivity for CMV was found for all ages. The highest seropositivity for T. gondii was observed among older participants. CONCLUSIONS: T. gondii remains an important pathogen owing to low seropositivity.

IL-28B genotypes as predictors of long-term outcome in patients with hepatitis C-related severe liver injury.

INTRODUCTION: Patients with severe fibrosis or cirrhosis are at high risk for liver-related complications, even after successful antiviral treatment and/or regression of fibrosis. These are the first published results concerning the role of IL-28B genotypes as predictors of the durability of sustained virological response (SVR) and long-term outcome, in patients with baseline severe fibrosis and cirrhosis caused by hepatitis C (HCV) infection. METHODOLOGY: Genetic testing for three different single nucleotide polymorphisms (SNP) near the IL28B gene, rs12979860, rs12980275 and rs8099917, was performed in 42 patients with HCV-related advanced fibrosis and cirrhosis, who achieved SVR after successful interferon-based treatment. Baseline clinical and laboratory parameters were analysed, as well as IL28B genotype association with late virological relapse, fibrosis progression and clinical outcomes. RESULTS: The most prevalent genotypes in all three tested SNP positions were: CCrs12979860 genotype in 69% of patients, GTrs8099917 in 78.6% and GGrs12980275 in 47.6% of patients. The presence of IL28B CCrs12979860 genotype was identified as a negative predictor of late virological relapse. Further analysis did not confirm the association of other IL28B genotypes with the progression of fibrosis and clinical outcomes. CONCLUSIONS: Varying long-term prognosis in patients with HCV-related severe fibrosis and cirrhosis is due to multiple interactions between host genetic factors, virus and environment. These are first published results demonstrating the significance of IL28B CCrs12979860 genotype as a negative predictor of late virological relapse. A further investigation concerning genetic factors is necessary to identify patients under risk for late relapse, complications and unfavorable outcomes, so that they can be reevaluated and offered new treatment options.

Serological status of childbearing-aged women for Toxoplasma gondii and cytomegalovirus in northern Kosovo and Metohija

Abstract INTRODUCTION: Toxoplasma gondii and cytomegalovirus (CMV) are pathogens associated with congenital anomalies. METHODS: Serum was collected from 79 reproductive-age women and tested for IgM and IgG antibodies to T. gondii and CMV. RESULTS: Seropositivity for T. gondii was detected in 24.1% of women and CMV in 96.2%. High seropositivity for CMV was found for all ages. The highest seropositivity for T. gondii was observed among older participants. CONCLUSIONS: T. gondii remains an important pathogen owing to low seropositivity.

The prevalence and the risk factors for hepatitis C virus infection in Serbia.

INTRODUCTION: The epidemiological characteristics of the hepatitis C virus (HCV) infection in Republic of Serbia have not been studied sufficiently so far. The aim of this study was to estimate the prevalence of anti-HCV positivity in the general population of Serbia and determine the risk factors for this infection. METHODOLOGY: Estimation of the prevalence was done using the median ratio method with data from several regional countries to a previously determined prevalence of anti-HCV positivity among volunteer blood donors of 0.19%. In order to determine the risk factors a matched case-control study was conducted of 106 subjects with confirmed HCV infection from the Clinic for Infectious and Tropical Diseases, Clinical Center of Serbia and the same number of hospital controls matched by sex and age. RESULTS: The estimated prevalence of anti-HCV positivity in the general population of Serbia was 1.13% (95% CI: 1.0-1.26%). The most important predictive risk factors of HCV infection were: intravenous drug use (OR = 31.0; 95% CI: 3.7-259.6), blood transfusions (OR = 3.7; 95% CI: 1.6-8.7), invasive dental treatment (OR = 3.1; 95% CI: 1.4-6.8), and low level of education (OR = 2.2; 95% CI:1.1-4.7). A total of 91.5% of the persons with hepatitis C had at least one of the significant risk factors. CONCLUSION: The prevalence of anti-HCV positivity ranks Serbia in the range of mid-endemic European countries. Preventive measures should be directed at preventing drug use, on education about getting the infection, creating safe conditions for blood transfusions, and strict adherence to adopted practices in dentistry.

Intravenous drug use - an independent predictor for HCV genotypes 3 and 4 infection among HIV/HCV co-infected patients.

INTRODUCTION: About one quarter of human immunodeficiency virus (HIV) infected persons in Serbia have also been found to be hepatitis C virus (HCV) co-infected. In the general population, HCV genotype 1 has been shown to be the most prevalent one. Here, we present the first study on the distribution of HCV genotypes among HIV/HCV co-infected patients in Serbia, in relation to epidemiological and clinical features. MATERIAL AND METHODS: The study included HIV/HCV co-infected and a group of HCV mono-infected patients in the period 1998-2012, with collection of epidemiological, clinical, and behavioral data using a standardized questionnaire. The HCV genotyping to the level of pure genotype was performed by reverse hybridization. RESULTS: Intravenous drug use (IDU) was found to be significantly more prevalent among the co-infected patients (p < 0.01). HCV genotype 1 was detected in 87% of patients with mono-infection, compared to 46.3% of patients with co-infection (p < 0.01); genotypes 3 and 4 were significantly more common among co-infected patients (6% and 5%, vs. 27% and 25%, respectively). Multivariate logistic regression confirmed IDU, infection with non-1 HCV genotype and HCV viral load over 5 log to be predictors of HIV co-infection. CONCLUSIONS: The HCV genotypes 3 and 4 were found to be significantly more prevalent among HIV/HCV co-infected patients in Serbia, compared to HCV mono-infected patients, but also more prevalent compared to the European HIV/HCV co-infected cohort. History of IDU represents an independent predictor of HCV genotypes 3 and 4 infection, with important implications for treatment.

Translation and validation of the Serbian primary biliary cholangitis-40 questionnaire.

BACKGROUND AND AIMS: To translate into Serbian and validate the Primary Biliary Cholangitis-40 (PBC-40) and PBC-27 questionnaires. MATERIALS AND METHODS: Ninety-four consecutive outpatients with the diagnosis of PBC from three departments across two tertiary care institutions in Belgrade were enrolled from February to October 2016. Standard methodology for cultural adaption of healthcare related quality of life questionnaires was used, and included: a forward translation, backward translation and a pilot test of the Serbian PBC-40 on five patients who gave suggestions and comments. For evaluation of the questionnaires, acceptance was shown by the proportion of missing items and the internal consistency was assessed using Cronbach's α coefficient. The PBC-40 was self-administered under the supervision of an experienced hepatologist. The PBC-27 is a shorter version of the PBC-40. RESULTS: A total of 92 (97.9%) of the patients were females. The mean age was 59.26 ± 1.05 years and the average length of disease was 60.45 ± 48.314 months. The average PBC-40 score was 85.62 ± 30.46. The total time needed to complete the questionnaire ranged from 7 to 16 minutes. The proportion of missing items was 5.45% (205/3760). Cronbach's α for the entire scale was 0.93. Reliability for all of the domains of the PBC-40 was above 0.70, except for the domain "Symptoms" (α = 0.52). Overall reliability of the PBC-27 was α = 0.90. Domains "Dryness", "Symptoms" and "Fatigue" demonstrated reliability below α = 0.70. CONCLUSIONS: The Serbian PBC-40 is a valid and reasonably adequate for use in Serbian PBC patients. The PBC-40 is preferred over the PBC-27.

ANTIVIRAL TREATMENT OF HEPATITIS C IN SERBIAN PRISON SETTING: MEDICAL TREATMENT OUTCOMES AND PATIENTS' ADHERENCE.

INTRODUCTION: Seroprevlence of chronic hepatitis C viral infection in correctional facilities ranges from 16% to 49%. However, there are only very limited data available on the course of hepatitis C viral infection and outcomes oftreatment with pegylated interferon plus ribavirin in correctional settings. The aim ofthis study was to assess the feasibility and effectiveness of use of pegylated interferon plus ribavirin treatment in the Serbian correctional setting. MATERIAL AND METHODS: The study sample consisted of the patients with hepatitis C hospitalized in the Special Hospital for Prisoners in Belgrade (Serbia) during 2007-2013. Health authorities approved treatment for 32 patients out of 76 treatment-naive patients referred to this institution. The patients (N=32) received 180 mcg pegylated interferon alfa-2a once a week plus oral ribavirin in dosage of 800 mg or 1000/1200 mg/day for 24 or 48-week treatment. All patients who completed therapy were assessed at the end of an additional 24-week treatment-free period for a sustained virological response. RESULTS: Sustained virological response was achieved in 53.8% of hepatitis C viral infection genotype I patients and in 73.3% and 66.6% of patients with hepatitis C viral infection genotype 3 and 4, respectively. One patient with mixed genotype (1, 2) did not achieve sustained virological response. The overall safety profile of the treatment regimen was very good. The incidence of influenza-like symptoms and depression were low A serious adverse event was recorded only in 6.4% of patients. CONCLUSION: The results showed that pegylated interferon alfa-2a plus ribavirin given once a week was well tolerated among prisoners and the regimen had the same adherence and effectiveness as in general population.

Boceprevir in genotype 1 chronic hepatitis C: first experiences in Serbia.

INTRODUCTION: The triple therapy which consists of one of the protease inhibitor plus pegylated interferon and ribavirin (P/R) is the standard of care for the treatment of chronic hepatitis C virus (HCV) genotype 1 (G1) infection both in treatment-naïve and experienced patients. OBJECTIVE: The aim of this study was to analyze the efficacy and tolerability of this regime in hospital practice in Serbia. METHODS: From July 2012 to October 2012, 20 previously treated patients with advanced fibrosis and HCV G1 infection were included in the triple antiviral regimen in six referral centers in Serbia. All patients were treated with response guide therapy (RGT) regime according to the boceprevir treatment protocol. During the 4-week lead-in period all patients received peginterferon plus ribavirin. After the lead-in pe- riod boceprevir was added in the dosage of 800 mg three times a day orally.The subsequent treatment varied according to virologic response and fibrosis. During the therapy HCV RNA level was measured at week 4, 8, 12, 24 of the treatment for the assessment of virologic response profile. All patients who completed therapy were assessed at the end of the treatment and at the end of an additional 24-week treatment-free period for a sustained virologic response (SVR). RESULTS: The total of 20 patients with advanced fibrosis was treated. Among patients with an undetectable HCV RNA level at week 8 the rate of SVR was 100%. No patient with decrease in the HCV RNA level < 1 log 10 IU/ml at treatment week 4 achieved SVR. The overall rate of SVR was 55%. The safety profile of the treatment regimen was good. Anemia was reported in 25% of patients. There was no life-threatening treatment adverse event. CONCLUSION: Boceprevir in combination with P/R achieved fairly good SVR rates in patients that were"most difficult to treat"who failed on dual therapy and was effective among patients with cirrhosis.

Seroprevalence and risk factors for hepatitis C virus infection among blood donors in Serbia: A multicentre study.

BACKGROUND: The epidemiological characteristics of hepatitis C virus (HCV) infection have not yet been described in Serbia. AIMS: To determine the prevalence of anti-HCV-positive individuals among first-time blood donors and the risk factors for hepatitis C transmission. METHODS: A multicentre case-control study nested within a prospective cohort study was conducted at 10 main transfusion centres in Serbia in 2013 and 27,160 blood donors who gave blood for the first time were included. Blood donors with confirmed anti-HCV positivity and seronegative controls were enrolled to determine the risk factors. RESULTS: Of 27,160 blood donors 52 were anti-HCV-positive; seroprevalence was 0.19%. By univariate analysis, marital status, educational level, drug use, previous transfusion, tattooing, non-use of condoms and number of sexual partners, were risk factors for hepatitis C. In the final multivariate analysis, three factors remained independently predictive: drug use, tattooing and previous blood transfusion. In total, 87.5% of cases had at least one of the risk factors for HCV transmission; 20.9% presumed that they knew when the infection occurred. CONCLUSION: HCV seroprevalence in Serbia is higher than in developed European countries. Preventive measures need to be directed towards drug use and tattooing facilities. The admission questionnaire for blood donors should be improved.

The significance of hepatitis B virus (HBV) genotypes for the disease and treatment outcome among patients with chronic hepatitis B in Serbia.

BACKGROUND: Hepatitis B virus (HBV) genotypes influence disease progression and treatment outcome. OBJECTIVES: To determine natural history and treatment outcome in patient chronically infected with HBV. STUDY DESIGN: A cohort study included 162 treatment naive patients with chronic HBV infection in order to analyze factors influencing natural history of infection and survival. RESULTS: Genotype A was far less prevalent, detected in 14.2%. The prevalence of HbeAg+ serology of 60.8% among patients infected with genotype A was significantly higher then 30.9% recorded among those with genotype D (P=0.02). Even though patients from two genotypes subgroups had significantly different prevalence of HBeAg serology, their viral loads were similar at the time of diagnosis (2.90 log10 and 3.31 log10 HBV DNK IU/µl plasma, for genotypes A and D, respectively). The analyses of viral loads across three serologic patterns of chronic HBV infection were: for HBeAg+/HBeAb-, HbeAg-/HBAb+, and both "e" antigen and antibodies negative: 4.24, 2.67 and 2.69 log10 IU/ml of HBV DNA IU/µl, respectively (P=0.01). Mean time to liver cirrhosis was 23.2±3.4 years and 15.1±8.4 years, for genotypes A and D, respectively (P=0.02). The overall estimated mean survival of patients with chronic HBV infection was 28.4 years, and was influenced by the stage of liver disease, but not by gender, age above 40, viral genotype and lamivudine therapy. CONCLUSIONS: Patients infected with genotype D had more rapid progression to ESLD regardless of levels of viral replication. All clinical and laboratory differences between genotypes did not affect survival of patients with chronic hepatitis B, regardless of lamivudine therapy.

[Efficacy and safety of peginterferon alfa-2a and ribavirin treatment of chronic hepatitis C in the Republic of Serbia].

INTRODUCTION: Hepatitis C virus (HCV) infection is one of the main causes of chronic liver disease worldwide. Pegylated interferon alfa-2a or 2b (PEG IFN alfa-2a or 2b) and ribavirin (RBV) represent a standard treatment of chronic hepatitis C (CHC). Sustained virological response (SVR), defined as continued undetectable HCV RNA 24 weeks after completion of treatment, is universally considered as an indicator of treatment efficacy. OBJECTIVE: The aim of this study was to determine efficacy and safety of PEG IFN alfa-2a and RBV treatment in patients with CHC in Serbia. METHODS: One hundred seventy-six patients with CHC were included in this multicenter trial from 8 reference centers in Serbia. The patients were treated with standard PEG IFN alfa-2a and RBV protocol. We performed the following virological testing: anti-HCV (ELISA), HCV RNK (quantitative PCR), HCV genotype (type-specific PCR), HBsAg, anti-HBs, anti-HBc and anti-HIV (ELISA). Histological activity and the degree of fibrosis were determined according to the Metavir scoring system. Potential predictors for achieving SVR were evaluated using multivariable logistic regression analysis. RESULTS: Of the treated patients with CHC 65.9% were male, and 60.2% of them aged over 40 years. Of the treated patients 68.2% had infection over 5 years, 63% had HCV RNA >400.000 IU/mL, 76.1% had HCV G1/4, and 60.1% had a mild to moderate liver fibrosis. SVR was achieved in 78.9% of patients (G1/4 79.1%; G2/3 78.1%). The factors that indicated a poorer efficacy of the treatment were age >40 (p<0.05), high basal viremia (p=0.013), and the reduction of PEG IFN alfa-2a and RBV doses, with interruption of therapy (p<0.001). Of the treated patients 45.9% had adverse affects (G1/4 50.8%; G2/3 29.7%). CONCLUSION: Treatment of CHC with PEG IFN alfa-2a and RBV was efficient in 78.9% of patients. The safety profile of therapy was satisfactory. Longer therapy increases the possibility of the development of adverse affects. No life-threatening adverse effects were recorded in our patients.

[Therapeutic approach to actinomycosis--experience gained at the department of infectious and tropical diseases].

INTRODUCTION: Actinomycosis is a chronic infectious disease caused by anaerobic, gram-positive microorganisms from the order of Actinomyce or Propionobacterium. The disease manifests iself mostly in cervicofacial form and less frequently in thoracic and abdominal form. The study was aimed at reviewing clinical manifestations and therapeutic approaches in treatment of patients with Actinomycosis. MATERIAL AND METHODS: The study sample consisted of four patients with different clinical manifestations of Actinomycosis, who had been treated at the Institute for Infectious and Tropical Diseases in Belgrade in 2002, 2003, 2006 and 2008. RESULTS: Four patients with Actinomycosis were treated during the above mentioned periods of time. One patient had kidney Actinomycosis, which developed into generalized Actinomycosis. Two patients had the most common cervical form, while the forth one had abdominal form; all patients received Penicillin G followed by Ampicillin, during the period of four weeks to up to a year. CONCLUSION: Actinomycosis is a rare disease, which imposes great diagnostic dilemmas. The treatment of this disease requires long term use of antibiotics.

Molecular characterization and phylogenetic analysis of full-genome HBV subgenotype D3 sequences from Serbia.

Hepatitis B virus (HBV) is classified into 8 genotypes with distinct geographical distribution. Genotype D (HBV/D) has the widest distribution area and is comprised of 7 subgenotypes. Subgenotypes D1, D2 and D3 appear worldwide, while D4-D7 have a more restricted distribution. Within the Mediterranean area, HBV/D and subgenotype D3 are the most prevalent. The purpose of this study was to characterize the full genome of Serbian HBV/D3 isolates by comparison and phylogenetic analysis with HBV/D3 sequences (66 samples) found in GeneBank/DDBJ databases from different parts of the world. Isolates were obtained from three patients diagnosed with chronic hepatitis B (HBsAg+). All three isolates have two very rare nucleotide substitutions, A929T and T150A, which indicate the same ancestor. Phylogenetic analysis of HBV/D3 genome sequences throughout the world follows an ethno-geographical origin of isolates with rare exceptions, which could be explained by human travelling and migration. The geographically close but ethnically different Serbian and Italian isolates clustered in the same subnode, and on a common branch with strains from Northern Canada. To test the apparently close HBV phylogenetic relationship between completely separated patients from Serbia and Northern Canada we analyzed in depth a 440 bp region of the HBsAg from Canadian (n=73) and Serbian (n=70) isolates. The constructed parsimony tree revealed that strains from Serbia and Northern Canada fell along the same branch which indicates independent evolution within regions of each country. Considering that HBsAg sequence has limited variability for phylogenetic analyses, our hypothesis needs further confirmation with more HBV complete genome sequences.