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During the four pandemic waves, a total of 560,504 cases and 10,178 deaths due to COVID-19 were reported in Croatia. The Alpha variant, dominant from March 2021 (>50% of positive samples), was rapidly replaced by Delta variants (>90%) by August 2021. Several seroprevalence studies were conducted in different populations (general population, children/adolescents, professional athletes, healthcare workers, veterinarians) and in immunocompromised patients (hemodialysis patients, liver/kidney transplant recipients). After the first pandemic wave, seroprevalence rates of neutralizing (NT) antibodies were reported to be 0.2–5.5%. Significantly higher seropositivity was detected during/after the second wave, 2.6–18.7%. Two studies conducted in pet animals (February-June 2020/July–December 2020) reported SARS-CoV-2 NT antibodies in 0.76% of cats and 0.31–14.69% of dogs, respectively. SARS-CoV-2 NT antibodies were not detected in wildlife. Environmental samples taken in the households of COVID-19 patients showed high-touch personal objects as most frequently contaminated (17.3%), followed by surfaces in patients’ rooms (14.6%), kitchens (13.3%) and bathrooms (8.3%). SARS-CoV-2 RNA was also detected in 96.8% affluent water samples, while all effluent water samples tested negative. Detection of SARS-CoV-2 in humans, animals and the environment suggests that the ‘One Health’ approach is critical to controlling COVID-19 and future pandemics.

Introduction: The study aimed to investigate the prevalence and titres of anti-SARS-CoV-2 antibodies in children treated at the Children’s Hospital Zagreb in the first and the second wave of the COVID-19 pandemic. Statistical significance of difference at two time points was done to determine how restrictive epidemiological measures and exposure of children to COVID-19 infection affect this prevalence in different age groups.Materials and methods: At the first time point (13th to 29th May 2020), 240 samples and in second time point (24th October to 23rd November 2020), 308 serum samples were tested for anti- SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA) and electrochemilumines-cence immunoassay (ECLIA). Confirmation of results and titre determination was done using virus micro-neutralization test. Subjects were divided according to gender, age and epidemiological history. Results: Seroprevalence of anti-SARS-CoV-2 antibodies differs significantly in two time points (P = 0.010). In first time point 2.9% of seropositive children were determined and in second time point 8.4%. Statistically significant difference (P = 0.007) of seroprevalence between two time points was found only in a group of children aged 11-19 years. At the first time point, all seropositive children were asymptomatic with titre < 8. At the second time point, 69.2% seropositive children were asymptomatic with titre ≥ 8. Conclusions: The prevalence of anti-SARS-CoV-2 antibodies was significantly lower at the first time point than at the second time point. Values of virus micro- neutralization test showed that low titre in asymptomatic children was not protective at the first time point but in second time point all seropositive children had protective titre of anti-SARS-CoV-2 antibodies.

In May 2018, measles was introduced in the Dubrovnik region by an adult who recently travelled to Kosovo*. Control measures and an outbreak investigation were implemented: 15 epidemiologically-linked cases met the outbreak case definition of a visitor/resident of Dubrovnik-Neretva County with laboratory-confirmed measles and symptom onset beginning on May 19. New cases were identified through hospitals and primary care physicians. Throat swabs, urine and/or serum samples were collected from outbreak cases. RT-PCR detection of viral RNA and IgM/IgG was used to confirm infection. The median age of cases was 33 years, with one 8 month-old infant. Vaccination status was unknown for 9 cases, three were unvaccinated, one case had history of one dose and two cases reported receiving two doses of measles-containing vaccine. There were 11 hospitalisations and one person developed pneumonia. Control teams undertook an extensive search of contacts and implemented a range of control measures. Despite the outbreak occurring at the beginning of the summer tourism season, it was contained and did not spread to neighbouring regions. With continuing measles transmission in Europe, even small outbreaks create a burden on the health system in countries which have eliminated measles, and illustrate the importance of maintaining high immunisation coverage.

In June 2019, the Croatian Institute of Public Health was informed of a cluster of patients with laboratory confirmed tick-borne encephalitis (TBE) from the Gorski Kotar region. Five of the six patients with TBE reported consuming raw (unpasteurized) goat milk in the two week period before symptom onset, and one reported a recent tick bite. To assess risk factors for infection, we selected six control individuals from among healthy family and community members, and conducted a case-control analysis. None of the cases or controls were vaccinated against TBE. Individuals with TBE (cases) had 25 (95 % CI 0.8- 1410.2, p = 0.021) times higher odds of raw goat milk consumption compared to healthy controls. Milk samples from 12 goats from the implicated farm were tested for the TBE virus (TBEV) using RT-PCR. TBEV RNA was not detected in the milk, but serological testing of goats and other farm animals yielded evidence of exposure to the virus: Six goats from the flock had TBEV neutralizing antibodies. Our findings suggest that the vehicle for the outbreak was raw goat milk from a single farm. Following public health advice to cease consumption of raw dairy products, no further cases have been reported.

The brucellosis and Q-fever coinfection is very rarely reported. To our knowledge, this is the first case report of concomitant brucellosis and Q-fever, most likely imported in Croatia. A 30-year-old male agricultural worker was hospitalized on 22 April 2017 after a ten days fever up to 40°C with chills, shivering, excessive sweating, general weakness, loss of appetite and headache. A month and a half prior to the hospitalization he lost 18 kg of body weight. Three weeks before hospitalization the patient returned from Kupres (Bosnia and Herzegovina) where he was working for the past year on a sheep farm and consumed unpasteurized dairy products of sheep origin. At admission, his condition was moderately severe due to pronounced dehydration. Routine laboratory tests showed slightly elevated erythrocyte sedimentation rate, anemia, thrombocytopenia and elevated liver transaminases. The chest X-ray showed an inhomogeneous infiltrate of the lower right lung. Three sets of blood culture were cultivated. After 48 hours incubation, bacterial growth was detected in aerobic bottles. Gram-stained smear revealed small, gram-negative coccobacilli. Specimens were subcultured on blood and chocolate agar plates. Using a Vitek GN identification card, the isolated organism was identified as Brucella melitensis. 16S rRNA gene sequencing of the isolate confirmed it as a Brucella sp. Rose-Bengal test was positive, while Wright agglutination test showed a significant increase in antibody titer from 80 to 640 in paired sera. Using indirect immunofluorescence assay (IFA), Coxiella burnetii phase II IgM/IgG titers were 50 and 1024, respectively indicating acute Q-fever. The patient was treated with doxycycline and rifampicin. So far, there has been no relapse or signs of chronic infection.

Ospice su virusna bolest čije su glavne značajke vrlo visoka kontagioznost, pojava karakterističnog osipa, prolazna supresija imunološkog sustava i relativno česte komplikacije vezane uz dišni i središnji živčani sustav. Pronalaskom učinkovitog cjepiva i njegovom uporabom incidencija ove bolesti u svijetu značajno se smanjila, a u Sjedinjenim Američkim Državama 2000. godine proglašena je eliminacija ospica. U Europi se u posljednjih 6 godina incidencija smanjila za 90 %, ali se povremene epidemije još uvijek detektiraju. U nerazvijenom dijelu svijeta ospice su još uvijek jedan od vodećih uzročnika smrti u djece, a u razvijenom dijelu svijeta ospice se javljaju u necijepljenih osoba mlađe i srednje životne dobi i predstavljaju javnozdravstveni izazov na globalnoj razini. U Hrvatskoj je obavezno cijepljenje uvedeno 1969. godine. Posljednjih 20-ak godina godišnje se detektira desetak slučajeva s povremenim manjim epidemijama uzrokovanim importiranim virusima. Veća epidemija s ukupno 220 prijavljenih slučajeva zabilježena je 2014./2015. godine. Detekcija kliničkih slučajeva, epidemiološki nadzor i laboratorijska potvrda ospica, koja uključuje genotipizaciju virusa, ključni su postupci pri otkrivanju izvora infekcije i praćenju puta prijenosa., Measles is a very contagious viral disease characterized with appearance of rash, transient immunosuppression and relatively frequent complications related to respiratory tract and central nervous system. Development of an effective vaccine and vaccination has significantly reduced measles incidenceall over the world, with elimination of measles declared in the United States in 2000. In Europe,during last six years the incidence decreased by 90 %, but occasional outbreaks are still detected. In the developing world, measles is still one of the leading causes of death in children, while in the developed countries measles occur in unvaccinated young and middle-aged persons,representing a public health challenge globally. In Croatia, the mandatory vaccination was introduced in 1969. During last 20 years approximately ten cases have been detectedannually,with occasional small outbreaks caused by imported viruses. Large outbreak with a total of 220 reported cases has been recorded in 2014/2015. Detection of clinical cases, epidemiological surveillance and laboratory confirmation of measles including genotyping, are crucial steps in tracing the source of infection and monitoring transmission. Eradication of measles can be achieved only by a consistent vaccination with twodoses schedule regimen.

In 2017 Zagreb faced the largest outbreak of haemorrhagic fever with renal syndrome (HFRS) to date. We investigated to describe the extent of the outbreak and identify risk factors for infection. We compared laboratory-confirmed cases of Hantavirus infection in Zagreb residents with the onset of illness after 1 January 2017, with individually matched controls from the same household or neighbourhood. We calculated adjusted matched odds ratios (amOR) using conditional logistic regression. During 2017, 104 cases were reported: 11–81 years old (median 37) and 71% (73) male. Compared with 104 controls, cases were more likely to report visiting Mount Medvednica (amOR 60, 95% CI 6–597), visiting a forest (amOR 46, 95% CI 4.7–450) and observing rodents (amOR 20, 95% CI 2.6–159). Seventy per cent of cases (73/104) had visited Mount Medvednica prior to infection. Among participants who had visited Mount Medvednica, cases were more likely to have drunk water from a spring (amOR 22, 95% CI 1.9–265), observed rodents (amOR 17, 95% CI 2–144), picked flowers (amOR 15, 95% CI 1.2–182) or cycled (amOR 14, 95% CI 1.6–135). Our study indicated that recreational activity around Mount Medvednica was associated with HFRS. We recommend enhanced surveillance of the recreational areas during an outbreak.

Purpose: To present a case of acute anteroseptal ST-elevation myocardial infarction in the West Nile virus (WNV) meningoencephalitis. Methods & Materials: A 77- year-old patient was hospitalized in the late summer of 2017 on the second day of the illness manifested by a fever up to 38.6 °C and diarrhea. The patient did not report recent travel but recalled mosquito bites. Past medical history included hypertension. At admission, routine laboratory tests, electrocardiogram (ECG) and chest x-ray were performed. In addition, cerebrospinal fluid (CSF), urine and blood samples were collected for a virological analysis. Results: At admission, WBC count was 24.6 (reference range 3.4-9.7x10(9)/L) with neutrophilia (92%, range 44-72%) and very high levels of cardiac enzymes: creatinine phosphokinase 1856 (range 17-153 U/I), lactate dehydrogenase 433 (range 2-241 U/L), myoglobin 3116 (range 20-80 ug/L) and troponin I 17.640 (range 0.000-0.056 ug/L). ECG showed ST elevation. In the cardiac intensive care unit, an emergency coronary angiography was performed which confirmed the coronary artery stenosis. The patient's condition complicated on the 4th day of the illness by an altered level of consciousness with progression to coma, accompanied by neck stiffness and positive meningeal signs. Computed tomography of the brain was normal. Cerebrospinal fluid (CSF) showed pleocytosis with 26 cells/mm3, predominantly mononuclears (73%) and elevated protein level (1.151, range 0.170-0.370 g/L). Both CSF and urine were positive for WNV RNA by real- time and nested RT-PCR. Phylogenetic analysis showed WNV lineage 2. The patient was initially treated with acyclovir, ampicillin and cefepime parenterally with supportive therapy (antiedematous, antiaggregation and antihypertensive therapy). On the 8th day of the illness a respiratory insufficiency developed. The patient was intubated and mechanically ventilated, but developed hypotension and low oxygen saturation in spite of an adequate respiratory support. Despite the cardiopulmonary resuscitation, the patient died due to cardiopulmonary arrest. Conclusion: Although cardiac involvement is not frequently reported in the course of a WNV infection, physicians should be aware of the possibility of a WNV-related myocardial infection.

Objective Pneumococcus is a known cause of meningitis, pneumonia, sepsis, and acute otitis media in children and adults globally. Two new vaccines for children have the potential to prevent illness, disability, and death, but these vaccines are expensive. The Croatian Ministry of Health has considered introducing the vaccine in the past, but requires economic evidence to ensure that the limited funds available for health care will be used in the most effective way. Methodology Croatia appointed a multidisciplinary team of experts to evaluate the cost-effectiveness of introducing pneumococcal conjugate vaccination (PCV) into the national routine child immunization program. Both 10-valent and 13-valent PCV (PCV10 and PCV13) were compared to a scenario assuming no vaccination. The TRIVAC decision-support model was used to estimate cost-effectiveness over the period 2014–2033. We used national evidence on demographics, pneumococcal disease incidence and mortality, the age distribution of disease in children, health service utilization, vaccine coverage, vaccine timeliness, and serotype coverage. Vaccine effectiveness was based on evidence from the scientific literature. Detailed health care costs were not available from the Croatian Institute for Health Insurance at the time of the analysis so assumptions and World Health Organization (WHO) estimates for Croatia were used. We assumed a three-dose primary vaccination schedule, and an initial price of US$ 30 per dose for PCV10 and US$ 35 per dose for PCV13. We ran univariate sensitivity analyses and multivariate scenario analyses. Results Either vaccine is estimated to prevent approximately 100 hospital admissions and one death each year in children younger than five in Croatia. Compared to no vaccine, the discounted cost-effectiveness of either vaccine is estimated to be around US$ 69,000–77,000 per disability-adjusted life-years (DALYs) averted over the period 2014–2033 (from the government or societal perspective). Only two alternative scenarios were borderline cost-effective (US$ per DALY averted less than 3 × GDP per capita of approximately US$ 40,000). The first was a scenario based primarily on the WHO 2008 pneumococcal disease burden estimates for Croatia. The second was a scenario that assumed a fairly dramatic drop in the price of the vaccine over the period. Both vaccines would need to be priced at approximately US$ 20 per dose or less to be considered cost-effective under base-case assumptions. PCV10 would be more cost-effective than PCV13 with base-case assumptions, but this is sensitive to the price of each vaccine. Conclusion Based on estimated health and economic benefits in children alone, PCV is unlikely to be cost-effective in Croatia. Both vaccines would need to be priced at less than US$ 20 per dose to be considered cost-effective for children. Further analyses should be conducted to estimate the health and economic burden of pneumococcal disease in older age groups, and to assess the influence on cost-effectiveness results when short-term and long-term indirect effects are included for older individuals. While there are important uncertainties around the price and effectiveness of both vaccines, our analysis suggests there is insufficient evidence to warrant a significant difference in the price of the two vaccines.

Cytomegalovirus (CMV) is an important pathogen in immunocompromised individuals. The aim of this study was to analyze prevalence and dynamics of CMV infection among patients undergoing chronic hemodialysis. From 2010 to 2012, a total of 162 patients and 160 control subjects were tested for the presence of CMV IgM and IgG antibodies using enzyme‑linked immunosorbent assay. IgM/IgG reactive samples were further evaluated for IgG avidity to confirm or rule out recent primary CMV infection. The overall IgG seropositivity was higher in hemodialysis patients compared to controls (90.7% vs. 81.9% ; crude odds ratio [OR] =2.02, 95% confidence interval [CI] =1.05–3.89 ; OR adjusted for age and gender = 2.18, 95% CI = 1.05–4.55). CMV IgG antibody titers were similar in both groups. There was no difference in CMV prevalence between males (87.9%) and females (96.3%). According to age, a progressive increase in seropositivity was observed in both hemodialysis patients and the control group. Three hemodialysis patients (1.9%) developed recurrent CMV infection (positive IgM with high avidity IgG antibodies). In one patient (2.9%), seroconversion was documented during the second year of the follow‑up period indicating primary infection. In contrast, in the control group, recent primary CMV infection (positive IgM with low/borderline IgG avidity) was demonstrated in three subjects (1.9%), whereas one (0.6%) developed recurrent infection. On multivariate logistic regression, hemodialysis and older age were significant predictors for CMV seropositivity.

Objective: The aim of this study was to review the epidemiology of hepatitis a virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis D virus (HDV) infections in Croatia with emphasis on the influence on the national health and health care system. Materials and Methods: We conducted a literature search of data on the epidemiology of viral hepatitis in Croatia with a review of national data from our reference centers. Results: Since the year 2000, the incidence of hepatitis A in Croatia has shown a continuous and stable decline with only four cases recorded in 2012. Concerning chronic HBV infection, Croatia is classified among the countries with a low prevalence, only

With emergence of MHC class I tetramers loaded with CD8+ T-cell viral epitopes, it is possible to study virus-specific CD8 cells in humans during infection and after vaccination. MHC class I tetramers was used to detect the frequency of haemagglutinin (HA)-specific T cells in 26 healthy influenza-vaccinated humans. Peripheral blood was collected before, and 7, 14 and 28 days after vaccination. Four-colour flow cytometry was used for monitoring of vaccine induced T-cell response. In 15 donors, two- to fivefold increase in frequency of HA-specific T cells was observed 7 days after vaccination. In addition, in 12 of these donors, this increase was accompanied with fourfold increase of H1N1 antibody titre. The increase in frequency of HA-specific CD8+/IFN-gamma+ cells was low and peaked 28 days after vaccination in three of the six donors tested. Frequencies of HA-specific CD8+ T cells and antibody titre returned to prevaccination values 1 year after vaccination. Subunit influenza vaccines have the ability to induce HA-specific CD8+ cells. As the immune response to this vaccine decreased significantly after 1 year, our results confirm the importance of annual immunization for adequate protection.

We analyzed prevalence, risk factors and hepatitis C virus (HCV) genotype distribution in different population groups in Croatia in the context of HCV epidemiology in Europe, with the aim to gather all existing information on HCV infection in Croatia which will be used to advise upon preventive measures. It is estimated that 35000-45000 of the Croatian population is chronically infected with HCV. Like in other European countries, there have been changes in the HCV epidemiology in Croatia over the past few decades. In some risk groups (polytransfused and hemodialysis patients), a significant decrease in the HCV prevalence was observed after the introduction of routine HCV screening of blood/blood products in 1992. Injecting drug users (IDUs) still represent a group with the highest risk for HCV infection with prevalence ranging from 29% to 65%. Compared to the prevalence in the Croatian general population (0.9%), higher prevalence rates were found in prison populations (8.3%-44%), human immunodeficiency virus-infected patients (15%), persons with high-risk sexual behavior (4.6%) and alcohol abusers (2.4%). Low/very low prevalence was reported in children and adolescents (0.3%) as well as in blood donors (0%-0.009%). In addition, distribution of HCV genotypes has changed due to different routes of transmission. In the general population, genotypes 1 and 3 are most widely distributed (60.4%-79.8% and 12.9%-47.9%, respectively). The similar genotype distribution is found in groups with high-risk sexual behavior. Genotype 3 is predominant in Croatian IDUs (60.5%-83.9%) while in the prison population genotypes 3 and 1 are equally distributed (52.4% and 47.6%). Data on HCV prevalence and risk factors for transmission are useful for implementation of preventive measures and HCV screening.

Virus krpeljnog encefalitisa (KE) je mali, ovijeni virus koji pripada porodici Flaviviridae, rodu Flavivirus, serokompleksu krpeljnog encefalitisa. Postoje tri podtipa virusa KE: europski, dalekoistočni i sibirski koji se razlikuju po zemljopisnoj rasprostranjenosti, vektoru i kliničkom očitovanju infekcije u ljudi. Bolest je rasprostranjena na širokom području od srednje Europe i Skandinavskog poluotoka do Japana. Virus KE se održava endemski u tzv. prirodnim žarištima gdje obitavaju rezervoari (mali glodavci) i vektori (krpelji roda Ixodes). I. ricinus je vektor europskog podtipa, a I. persulcatus dalokoistočnog i sibirskog podtipa virusa. Virus se u krpeljima prenosi transstadijski i transovarijski pa oni predstavljaju i rezervoare infekcije. Infekcija u ljudi najčešće nastaje nakon uboda zaraženog krpelja, ali je moguća i konzumacijom mlijeka i mliječnih proizvoda od zaraženih životinja. U tipičnom obliku bolest uzrokovana europskim podtipom virusa KE ima bifazičan tijek (50-77 % infi ciranih). Prva je faza obilježena nespecifi čnim simptomima nakon koje slijedi asimptomsko razdoblje nakon čega se u oko 20-30 % oboljelih pojavljuju znaci infekcije središnjeg živčanog sustava (meningitis, encefalitis, mijelitis, radikulitis). Mortalitet iznosi 1-2 %. Dijagnoza se obično potvrđuje serološkim metodama (imunoenzimni test, indirektni imunofl uorescentni test, neutralizacijski test redukcije plakova). U Hrvatskoj je u razdoblju od 1993. do 2013. godine prijavljeno ukupno 777 slučajeva KE. Bolest je endemska u sjeverozapadnim županijama (prosječna incidencija 3,61-6,78/100 000 stanovnika). Većina oboljelih su osobe starije od 20 godina (88 %). Najveći je broj infekcija (73 %) zabilježen u razdoblju od svibnja do srpnja., Tick-borne encephalitis virus (TBEV) is a small, enveloped virus that belongs to the family Flaviviridae, genus Flavivirus, tick-borne encephalitis serocomplex. There are three subtypes of TBEV: European, Far-Eastern and Siberian subtypes, which differ in geographical distribution, tick vector and clinical manifestation of disease in humans. TBEV is endemic in a wide geographic area ranging from Central Europe and the Scandinavian Peninsula to Japan. The virus is maintained in nature in so-called natural foci in cycles involving ticks and wild vertebrate hosts (mainly small rodents). The principal vector for the European subtype is Ixodes (I.) ricinus tick, whereas for Far-Eastern and Siberian subtypes it is I. persulcatus. In the Baltic States and Finland, co-circulation of two or all three subtypes was documented. Several animals, principally small rodents, serve as virus reservoirs. In the tick population, TBEV is transmitted by feeding/co-feed ing on the same host, transovarially (from infected females to their eggs) and trans-stadially (from one development stage to the next). An infected tick remains infected for life. While most TBE infections in humans occur following a tick bite, alimentary routes of TBEV transmission (consumption of unpasteurized milk/milk products from infected livestock) have also been described. All three tick stages can transmit the infection to humans. In the last decade, an increase of TBE incidence has been observed in some endemic areas. This could be due to a number of interacting factors such as changes in the climatic conditions affecting tick habitats, improvements in the quality of epidemiological surveillance systems and diagnostics, in landscape resources and their utilization and more outdoor recreation activity. In addition, the endemic area of TBEV has expanded to higher altitudes (up to 1500 m), apparently infl uenced by climatic changes. The typical clinical picture of infection with European subtype TBEV is characterized by a biphasic course (50%-77%). The fi rst phase is characterized by nonspecifi c, fl u-like symptoms followed by an asymptomatic interval of about one week. In 20%-30% of persons who develop symptoms, the second phase occurs with symptoms of central nervous system involvement (meningitis, encephalitis, myelitis, radiculitis). The mortality rate for European subtype is 1%-2%. Diagnosis is usually based on detection of specifi c antibodies (enzyme immunoassay, indirect immunofl uorescent assay, plaque reduction neutralization test). From 1993 to 2013, a total of 777 cases of TBE were reported in Croatia. Endemicity is highest in north-western counties (mean incidence 3.61-6.78/100,000 inhabitants). The majority of patients were older than 20 years (88%). Most cases (73%) were reported from May to July.

During 2011–2012, a total of 1008 serum samples from randomly selected inhabitants of seven Croatian counties located on the Adriatic Coast were tested for the presence of chikungunya virus (CHIKV) IgG antibodies using indirect immunofluorescence assay. Nine participants (0.9%) from four counties were found to be seropositive to CHIKV. Seroprevalence varied from 0.5% to 1.8% between counties. Additionally, a total of 3,699 mosquitoes were captured in 126 localities from August 16 to September 24, 2011. Three mosquito species were found: Ae. albopictus (3010/81.4%), Cx. pipiens (688/18.6%) and only one specimen of the Cs. longiareolata. Female mosquitoes (N = 1,748) were pooled. All pools tested negative for CHIKV RNA using a real-time RT-PCR.

SUMMARYThis is a retrospective study using the test-negative case-control method to estimate seasonal 2010–2011 influenza vaccine effectiveness (VE) in Croatia. Of patients consulting a physician for influenza-like illness (ILI) and for whom a swab was taken, we compared RT–PCR influenza-positive and RT–PCR influenza-negative patients. We used a structured questionnaire and physicians' records to obtain information on vaccination status and potential confounders. We conducted a complete case analysis using logistic regression to measure adjusted VE overall, against A(H1N1)pdm09 and in age groups. Out of 785 interviewed patients, 495 eligible patients were included in the study, after applying exclusion criteria [217 cases, of which 92·6% were A(H1N1)pdm09 positive, 278 controls]. Crude VE was 31·9% [95% confidence interval (CI) −40·9 to 67·1] and adjusted VE was 20·7% (95% CI −71·4 to 63·3), with higher VE in youngest and oldest age groups. Results from this first VE study in Croatia suggest a low to moderate VE for the 2010–2011 season. Studies year on year are needed with a greater sample size to provide more precise estimates, and also by age group and risk groups for vaccination.

In the frame of measles elimination activities, sera from 1205 Croatian citizens from all parts of the country and of all ages were tested, using Gull Laboratories ELISA, for measles IgG. Equivocal results were found in 50 subjects. Of the remaining 1155 participants, 118 or 10.2% were negative and 1037 or 89.8% positive. The proportion of seronegatives ranged from zero (age groups 41-50, 51 and more) up to 21.4% (1 year of age). As for their distribution into age groups suggested by the European Regional Office of WHO, there were 12.7, 8.9, 9.5 and 8.8% negatives in age groups 1-4, 5-9, 10-14 and 15 + years, respectively. According to these results, only the first two age groups meet WHO criteria, indicating that vaccination coverage higher than the reported 90-94% should be attained if one is to expect measles elimination.

The main aim of Croatia's epidemiological information system is to enable the monitoring of infectious diseases as well as to enable necessary interventions. Its 24-hour epidemiologic alert mechanism made it possible for initial reports of sudden death clusters in haemodialysis units to reach epidemiologists on the night of 12 October 2001. The alert about the sudden deaths among haemodialysis patients in two hospitals has prompted us to do an epidemiological inquiry during that night and early the next morning. It looked at suspicions of a possible link between Baxter Plivadial P-15 lot 2001F075 dialyser and these deaths. As the suspicion was based on a small amount of data, it needed confirmation from a countrywide inquiry involving the other 40 haemodialysis units. A phone inquiry showed that 23 haemodialysis deaths occurred on 8-13 October 2001. It suggested that also dialyser of a different type and lot (P-18 2001B17R) should be incriminated. During the inquiry (October 13), all haemodialysis units were informed of the suspicions regarding incriminated dialysers, and of the necessity of temporary withdrawal of these from use. The withdrawal on 13 October of incriminated dialysers stopped the deaths among haemodialysis patients. No more such sudden deaths have been recorded since that could be linked either to the described period or to this clinical picture.

Hrvatska je zemlja niske prevalencije virusnih hepatitisa A, B i C, hepatitis D se u Hrvatskoj ne javlja, a hepatitis E se javlja tek sporadično. S obzirom da je zahvaljujući poboljšanim uvjetima života i higijenskim uvjetima hepatitis A sveden na sporadičnu bolest, najčešći uzročnici virusnih hepatitisa u Hrvatskoj su hepatitis B i C. Uvođenje obveznog cijepljenja školske djece protiv hepatitisa B 1999. godine dovelo je do pada incidencije te bolesti u Hrvatskoj, s najvećim učinkom na adolescente i mlade odrasle osobe i može se očekivati daljnji pad njene incidencije i prevalencije. Incidencija hepatitisa C je također u blagom opadanju. Unatoč relativno povoljnoj situaciji u vezi s virusnim hepatitisima, hepatitis B i C i dalje su važan javnozdravstveni problem s obzirom da procjenjujemo da je oko 25 tisuća osoba u Hrvatskoj kronično zaraženo virusom hepatitisa B, a oko 40 tisuća virusom hepatitisa C., Understanding the country-specific epidemiology of disease, which may vary greatly among countries, is crucial for identifying the most appropriate preventive and control measures. An overview of the local epidemiology of viral hepatitis in Croatia is given in this paper. The overall prevalence of hepatitis B in Croatia is low (less than 2% HBsAg carriers in the general population). Hepatitis B incidence and prevalence began to decline significantly following the introduction of universal hepatitis B vaccination in 1999. Information on HBsAg seroprevalence is derived from routine testing of certain subpopulations (pregnant women, blood donors) and seroprevalence studies mostly targeted at high-risk populations. Universal childhood vaccination against hepatitis B remains the main preventive measure. We recommend testing for immunity one to two months after the third dose of hepatitis B vaccine for health-care workers. The incidence and prevalence of hepatitis C have also been declining in the general population. The main preventive measures are ensuring safety of blood products, prevention of drug abuse, and harm reduction programs for intravenous drug users. Hepatitis A incidence has declined dramatically since fifty years ago, when thousands of cases were reported annually. In the last five years, an average of twenty cases have been reported per year. The reduction of hepatitis A is a consequence of improved personal and community hygiene and sanitation. Hepatitis D has not been reported in Croatia. The risk of hepatitis D will get to be even smaller as the proportion of population vaccinated against hepatitis B builds up. Hepatitis E is reported only sporadically in Croatia, mostly in persons occupationally in contact with pigs and in travelers to endemic countries. In conclusion, Croatia is a low prevalence country for hepatitides A, B and C. Hepatitis D has not been reported to occur in Croatia and there are only sporadic cases of hepatitis E. Since hepatitis A is a rare disease occurring sporadically, which is a consequence of improved sanitation and hygiene, hepatitides B and C are the main causes of viral hepatitis in Croatia. The introduction of universal mandatory hepatitis B vaccination of schoolchildren in 1999 resulted in a decrease in the incidence of hepatitis B, which is most pronounced in adolescents and young adults, and further decrease in the incidence and prevalence is expected as the pool of susceptible individuals decreases through vaccination. The incidence of hepatitis C is decreasing as well. In spite of a relatively favorable epidemiological situation, hepatitis B and C are still a significant public health burden with an estimated 25,000 persons chronically infected with HBV and about 40,000 persons chronically infected with HCV in Croatia.

Croatian Consensus Conferences on Viral Hepatitis took place in 2005 and 2009. Considering the numerous novel concepts on the epidemiology, diagnosis and management of viral hepatitis (chronic hepatitis C genotype 1 in particular) that have emerged in the past four years, a new Croatian Consensus Conference on Viral Hepatitis was held in Zagreb on February 28, 2013. The abridged text of the Croatian Consensus Conference on Viral Hepatitis 2013 presents the new concepts on the epidemiology of viral hepatitis, serologic and molecular diagnosis of viral hepatitis, determination of the IL-28 gene promoter polymorphism, fibrosis grading, algorithm for patient diagnostic follow up, treatment of chronic hepatitis C (genotypes 1-6) and hepatitis B, treatment of special populations (children, dialysis patients, transplanted patients, individuals with HIV/HCV co-infection), and therapy side effects.

Seroprevalence data on viral hepatitis in the general population vary widely. The aim of this study was to determine the prevalence of hepatitis A (HAV), hepatitis B (HBV) and hepatitis C (HCV) viruses in the general Croatian adult population undergoing routine check-ups. The seroprevalence of anti-HAV, anti-HBc and anti-HCV was 40.5%, 7.0% and 0.9%, respectively. HBsAg was found in 0.7% and anti- HBs antibodies in 24.4% of participants. Gender was not associated with HAV, HBV or HCV seropositivity. HAV and HBV seropositivity increased progressively with age (HAV from 11.7% to 90.4%, p < 0.001 ; HBV from 1.7% to 15.8%, p < 0.001). Participants from rural areas showed a significantly higher HBV seroprevalence rate than those from urban areas (10.7% vs. 6.1%, p = 0.007). Results of univariate and multiple logistic regression showed that older age was a significant predictor for both HAV and HBV seropositivity while rural place of residence was a significant predictor for HBV seropositivity.

Dječja paraliza - bolest uzrokovana poliovirusom - poznata je od davnina. S pojavom epidemija u dvadesetom stoljeću poliomijelitis postaje globalni javno zdravstveni problem. Svjetska zdravstvena organizacija (SZO) 1988. godine započinje kampanju s ciljem eradikacije poliomijelitisa te je do danas broj slučajeva smanjen za više od 99 %. U Hrvatskoj je cijepljenje protiv dječje paralize započelo već 1961. godine i dovelo do dramatičnog smanjenja obolijevanja. Eradikacija poliomijelitisa u Hrvatskoj proglašena je 2002. godine istodobno s eradikacijom ove bolesti u Europi. Ipak, krajnji cilj - polio-free world još nije postignut. Stoga, radna skupina globalne inicijative za eradikaciju poliomijelitisa donosi „Završni strateški plan 2013-2018“ u kojem su razrađeni postupci s ciljem rješavanja: a) trajnog prijenosa divljeg soja u endemskim zemljama, b) reinfekcije područja bez poliomijelitisa i c) epidemija dječje paralize uzrokovanih cirkulirajućim sojevima proizašlim iz cjepiva (cVDPV, engl. vaccine derived poliovirus). Slijedi povlačenje oralnog, atenuiranog poliovirusnog cjepiva (OPV) i uvođenje inaktiviranog cjepiva (IPV) na globalnoj razini., Poliomyelitis is a very old disease of humans, caused by poliovirus. With appearance of the epidemics in the 20th century, poliomyelitis became a global public health issue. In 1988, the World Health Organization started a campaign for global eradication of poliomyelitis and till now poliomyelitis cases have been reduced by more than 99%. In Croatia, the introduction of vaccination in 1961 resulted in dramatic reduction of paralytic disease. The European region, including Croatia was certifi ed polio free in 2002. However, the fi nal goal of the “polio-free world” has not yet been reached. To reinforce the campaign, the global polio eradication initiative has come up with the Polio Eradication & Endgame Strategic Plan 2013-2018 with detailed program how to resolve the main challenges: (a) continued transmission of wild polioviruses in endemic reservoirs; (b) reinfection of polio-free areas; and (c) outbreaks due to the circulating vaccine-derived polioviruses (cVDPV). Global oral polio vaccine cessation will follow, with the introduction of universal use of inactivated polio vaccine.

We report on first evidence of simultaneous occurrence of West Nile virus (WNV) and Usutu virus(USUV) neuroinvasive infection in humans in Croatia during the transmission season 2013. From June to December 2013, a total of 95 patients with clinically suspected WNV infection (WNV fever and neuroinvasive disease) were tested for WNV IgM/IgG antibodies using enzyme-linked immunosorbent assay. Twenty-six reactive samples were further tested by virus neutralization test for confirmation. WNV neuroinvasive infection was confirmed in 20 patients, while in three patients USUV neutralizing antibodies were detected. Cases occurred during the 11-week interval (from 24 July to 07 October 2013). Both WNV and USUV cases were distributed in three northwestern Croatian counties. In addition to human cases, recent asymptomatic WNV infection (detection of IgM antibodies) was recorded in 9/3, 460 (0.3 %) tested sentinel horses. Infected animals were recorded in two eastern and one north-western county. Our results indicate co-circulation of WNV and USUV in Croatia. WNV infection could be misdiagnosed with other emerging infectious diseases presenting with neurological symptoms such as USUV infection.

Summary TBE in Croatia was first discovered in 1953 but its mandatory reporting, as a distinct nosological entity, was instituted in 1987. Data presented here concern the 1989–1998 decade. During this period a total of 500 cases of TBE was recorded, ranging from 23 (1990) to 87 (1994) per year, with an average of 50 cases annually. There is only one natural focus in the northern part of the country, between the rivers Sava and Drava. Alleged cases of TBE, as occurring out of the focus (Zadar and Pula), have not been certified. The seasonal distribution of TBE cases is typical, most cases occurring from May to July (75%). As for the age distribution of TBE, a substantial rise is seen after the age of 20, only some 3% of cases occurring in children younger than 10 years. The first documented cases of human Lyme borreliosis in Croatia were published in 1986, its official compulsory reporting starting in 1991. Since then 1464 cases were recorded with an annual average of some 150 cases, varying from 93 (1992) up to 335 (1996). The age distribution is somewhat different from TBE, since the age group 0–9 years recruits 20% of all cases. Nevertheless, most of the diseased are of adult age. About 92% of the cases occur between May and August. The disease occurs mostly in the inland, above the 45th parallel, and only sporadically on the Adriatic coast.

We present a review of the current implementation status of vaccination against human papillomaviruses (HPV) and available data concerning the burden of HPV infection and HPV type-specific distribution in 16 central and eastern European countries: Albania, Bosnia and Herzegovina, Bulgaria, Croatia, the Czech Republic, Estonia, Montenegro, Poland, Romania, Serbia, Slovakia, Slovenia, and The Former Yugoslav Republic of Macedonia. At least one current HPV prophylactic vaccine is registered in all central and eastern European countries except Montenegro. Six counties-Bulgaria, the Czech Republic, Latvia, Romania, Slovenia, and Former Yugoslav Republic of Macedonia-have integrated the HPV vaccination into their national immunization program and currently provide routine vaccination free of charge to the primary target population. Ten countries have not integrated HPV vaccination into the national immunization program. The key reasons for lack of implementation of HPV vaccination into the national immunization program are the high vaccine cost and negative public perception. Vaccination of males is not recommended in any country in the region.

Hrvatske konsenzus konferencije o virusnim hepatitisima održane su 2005. i 2009. g. (1). S obzirom na brojne nove spoznaje o epidemiologiji, dijagnostici i liječenju virusnih hepatitisa (poglavito kroničnog hepatitisa C genotipa 1) u protekle četiri godine, 28. veljače 2013. g. održana je nova Hrvatska konsensus konferencija o virusnim hepatitisima u Zagrebu. Sažeti tekst ove Hrvatske konsenzus konferencije o virusnim hepatitisima sadrži prikaz novih spoznaja o epidemiologiji virusnih hepatitisa, serološkoj i mo¬lekularnoj dijagnostici virusnih hepatitisa, određivanju polimorfizma promotora gena za IL-28, procjeni stadija fibroze, algoritmu dijagnostičkog praćenja bolesnika, liječenju kroničnog hepatitisa C (genotipovi 1-6) i hepatitisa B, liječenju specijalnih populacija (djeca, bolesnici na dijalizi, bolesnici liječeni transplantacijom, osobe s HIV/HCV koinfekcijom) i nuspojavama liječenja., Croatian Consensus Conferences on Viral Hepatitis took place in 2005 and 2009. Considering the numerous novel concepts on the epidemiology, diagnosis and management of viral hepatitis (chronic hepatitis C genotype 1 in particular) that have emerged in the past four years, a new Croatian Consensus Conference on Viral Hepatitis was held in Zagreb on February 28, 2013. The abridged text of the Croatian Consensus Conference on Viral Hepatitis 2013 presents the new concepts on the epidemiology of viral hepatitis, serologic and molecular diagnosis of viral hepatitis, determination of the IL-28 gene promoter polymorphism, fi¬brosis grading, algorithm for patient diagnostic follow up, treatment of chronic hepatitis C (genotypes 1-6) and hepatitis B, treat¬ment of special populations (children, dialysis patients, transplanted patients, individuals with HIV/HCV co-infection), and therapy side effects.

The aim of this study was to determine the immunity to varicella-zoster virus (VZV) in Croatian pregnant and non-pregnant women of reproductive age. During 2007-2011, a total of 638 women aged 16-45 years were tested for the presence VZV IgM and IgG antibodies using commercial enzyme-linked immunosorbent assay. Samples positive for IgG antibodies with positive or equivocal IgM antibodies were tested for IgG avidity. The overall IgG seroprevalence was 84.3%. There was a significant increase in IgG seropositivity with age (OR=1.04 for one year increase in age ; 95% CI=1.01-1.08). The lowest seroprevalence rate was reported in the 16-20 age group (78.6%), and the highest was in the 41-45 age group (94.3%). There was no significant difference in seroprevalence among women residing in urban and rural areas (83.6% vs. 87.0%, OR=0.76, 95% CI=0.43-1.34). The results of this study have shown that a high proportion of Croatian childbearing-aged women (15.7%) who were referred to the laboratory for VZV serology testing are susceptible to VZV and, thus, at risk for contracting varicella during pregnancy. Serology testing of adolescent girls and adult women who do not have a documented history of varicella is encouraged with the aim of vaccinating seronegative girls and women against VZV before pregnancy. Additionally, testing of pregnant women is advised in order to identify susceptible women and vaccinate them after delivery.

Cilj rada bio je prikazati virološke i epidemiološke značajke non-polio enterovirusnih (NPEV) infekcija u desetogodišnjem razdoblju(2000.-2009.) u Republici Hrvatskoj. Tijekom navedenog razdoblja u Laboratoriju za enteroviruse Hrvatskog zavoda za javnozdravstvo obrađeno je 2754 kliničkih uzoraka prikupljenih od 1880 bolesnika s kliničkom slikom enterovirusne infekcije. Dijagnoza enterovirusne infekcije dokazana je izolacijom virusa u staničnoj kulturi, a virusi su tipizirani metodama neizravne imunofluorescencije i/ili testom neutralizacije. NPEV infekcija dokazana je u 394 od 1880 bolesnika (21%). Osobe muškog spola češće su obolijevale od osoba ženskog spola u omjeru 1,8:1. Broj oboljelih najveći je u dobnoj skupini predškolske i školske djece. Bolesnici u kojih su izolirani NPEV najčešće su imali dijagnozu seroznog meningitisa - 234/394 (59,4%). Infekcije su najčešće bile uzrokovane echovirusima (218/394; 55,3%), zatim coxsackie B (126/394; 32,0%) i coxsackie A (31/394; 7,9%) virusima, a rjeđe su dokazani echovirus 22 - parechovirus 1 (16/394; 4,1%) i enterovirus 71 (3/394; 0,8%). Coxsackie B5 i B4 virusi kontinuirano se detektiraju tijekom istraživanog razdoblja s učestalijom pojavom svakih 4-5 godina. Najčešći izolat echovirusa bio je echovirus 18 koji se detektira kontinuirano od 2000. do svoje epidemijske 2006. godine. Echovirus 6 i echovirus 30 također se izoliraju kontinuirano s vršnim vrijednostima 2002. i 2008., odnosno 2002., 2006. i 2008. godine., Aim: The aim of the present study was to show the virologic and epidemiological characteristics of non-polio enterovirus (NPEV) infection over a ten-year period in Croatia. Methods: During the 2000-2009 period, the Laboratory for Enteroviruses, Croatian Public Health Institute analyzed 2754 clinical samples collected from 1880 patients with a clinical picture of enteroviral infection. The diagnosis of enteroviral infection was confirmed by virus isolation in cell culture. Viruses were typed using indirect immunofluorescence and/or neutralization assay. Results: NPEV was proven in 394 (21%) of 1880 patients. Males were more commonly infected than females, at a ratio of 1.8:1, while the number of infected cases was highest among preschoolers and schoolchildren. Patients with isolated NPEV were most frequently diagnosed with aseptic meningitis (234/394; 59.4%). Infections were most commonly caused by echoviruses (218/394; 55.3%), followed by Coxsackie B (126/394; 32.0%) and Coxsackie A (31/394; 7.9%) viruses, rarely by echovirus 22 - parechovirus 1 (16/394; 4.1%) and enterovirus 71 (3/394; 0.8%). In most cases, echoviruses of the following serotypes were proven: 6, 9, 11, 13, 14, 18 and 30 (45/218, 21%; 14/218, 6.4%; 18/218, 8.3%; 15/218, 6.9%; 11/218, 5.0%; 55/218, 25.2% and 42/218, 19.3%), while serotypes 2, 3, 4, 5, 7, 12, 20, 21, 25 and 26 were evidenced in a minority of patients or individual cases. Coxsackie B5 was the predominant serotype among Coxsackie B viruses (50/126, 40%), while Coxsackie A9 was most common Coxsackie A virus (26/31, 84%). Coxsackie B5 and B4 viruses were continually detected during the study period and appeared more frequently every four to five years. The most common echovirus isolate was echovirus 18, detected continually between 2000 and the outbreak year of 2006. Echovirus 6 and echovirus 30 were also isolated continually with peaks in 2002 and 2008, or 2002, 2006 and 2008. Conclusion: The results of this study pointed to a specific pattern of the occurrence of certain NPEV serotypes in Croatia. The epidemic pattern (echovirus 18 and Coxsackie B1) was characterized by peaks with an elevated number of isolations in given years. Contrary to this, endemic viruses were isolated in similar counts every year (Coxsackie B3), or manifested milder epidemic peaks every few years (echoviruses 30 and 6, Coxsackie B4 and B5). Data on NPEV infections, given their serotype and specific pattern of occurrence, contribute significantly to prompt diagnostic, clinical and epidemiological response to NPEV infections.

Despite the widespread distribution of Q fever, the prevalence in humans is not accurately known, because many infected people seroconvert without symptoms or with a mild febrile disease. The aim of this study was to determine the seroprevalence of Q fever in different regions of Croatia. During a 2-year period (2008–2010), serum samples from 552 febrile patients with prolonged cough aged 1–88 were tested for the presence of Coxiella burnetii antibodies by using indirect immunofluorescent assay. Sera from 27.5% patients showed IgG antibodies. Serological evidence of C. burnetii infection was found in patients from all parts of Croatia. Seroprevalence rates significantly differed among regions from 21.5% to 41.2% ( p = 0.001). Men were more often seropositive (31.6%)than women (22.2% ; p = 0.016). According to age, a progressive increase in the IgG seropositivity rates was observed as ranging from 6.7% in children less than 10 years of age to 39.2% in patients aged 40–49 ( p = 0.001). Above the age of 50, the IgG seroprevalence remained stable. Patients from rural areas were more often seropositive than patients from urban areas (40.8% vs. 19%), p < 0.001). Acute Q fever was confirmed in 5.8% of patients. Cases occurred throughout the year. A majority of cases were reported during summer months.

We are reporting on a household outbreak of measles, in which cases of simultaneous measles and chickenpox infection occured in children of a family who resided in Italy during the incubation period (June 2011). In three children, fever and generalized confluent macular rash were the dominant symptoms. Serology testing revealed simultaneous measles and chickenpox infection in four children.

We describe excretion of measles vaccine strain Schwarz in a child who developed a febrile rash illness eight days after primary immunisation against measles, mumps and rubella. Throat swabs and urine specimens were collected on the fifth and sixth day of illness, respectively. Genotyping demonstrated measles vaccine strain Schwarz (genotype A). If measles and rubella were not under enhanced surveillance in Croatia, the case would have been either misreported as rubella or not recognised at all.

We report an outbreak of measles in Croatia, involving 49 cases with onset of symptoms between end of April and June 2008. Cases occurred in Zagreb and Slavonski Brod but investigations indicated a common epidemiological link between these two geographically separate regions.

SummaryPost-traumatic stress disorder (PTSD) is an anxiety disorder that can occur after exposure to extreme traumatic experience such as war trauma, and is accompanied by fear, helplessness or horror. Exposure to trauma can result in immune dysregulation and influence susceptibility to infectious disease as well as vaccine efficacy. The aim of the study was to determine the relation of psychological stress and the immune response to influenza vaccination in combat-related PTSD patients (n = 28). Detection of anti-viral antibody titre was performed by inhibition of haemagglutination assay. Ex vivo tetramer staining of CD8+ T lymphocytes was used to monitor T cells specific for human leucocyte antigen (HLA)-A*0201-restricted influenza A haemagglutinin antigens before and after vaccination. Twenty patients showed a fourfold antibody titre increase to one or both influenza A viral strains, and 18 of them showed the same response for both influenza B viral strains. Ten of 15 healthy controls showed a fourfold rise in antibody titre to both influenza A viral strains and eight of them showed the same response for both influenza B viral strains. HLA-A*0201+ PTSD patients (n = 10) showed a significant increase of influenza-specific CD8 T cells after vaccination. Although those PTSD patients had a lower number of influenza-specific CD8+ T cells before vaccination compared to HLA-A*0201+ healthy controls (n = 6), there was no difference in influenza A antibody titre between PTSD patients and control subjects before vaccination. The generated humoral and cellular immune response in PTSD patients argues against the hypothesis that combat-related PTSD in war veterans might affect protection following influenza vaccination.

In this paper legal prerequisites for vaccine licensure in Croatia are discussed. The Croatian legislation concerning vaccine licensing, marketing authorisation and utilization is reviewed. The procedures for including a vaccine into the Mandatory Childhood Vaccination Programme are also discussed with focus on Human papillomavirus (HPV) vaccines. Non-obligatory vaccination recommendations are given when according to professional opinion ; vaccination is beneficial for the vaccinee. There is little doubt that HPV vaccines should be recommended for preadolescent girls in Croatia. However, reaching a decision on its possible introduction into the Childhood Vaccination Programme will require careful consideration of the larger picture and a comparison of the cost-effectiveness of a mandatory vaccination against other competing public health priorities.

In a Letter to the Editor published in Vaccine recently (Vaccine 24 (2006) 6371-6373), the authors describe clinical features of vaccine associated aseptic meningitis (AM) of patients hospitalized in one hospital, proceeding to calculate incidence rates of AM based on hospital admission data. Since the denominator for hospital-based cases is unknown, the incidence rates calculated in such a way are methodologically incorrect and should not be considered relevant.

We studied five patients with SSPE during a 10-year period (1994–2004). The first clinical symptoms developed at the age of 5–11 years. All patients were vaccinated regularly against measles according to the official immunization schedule. One patient had measles at the age of 18 months. Two of them had a history of morbilliform rash (unrecognized measles) at the age of six and seven months, respectively. In two patients, with no history of measles before vaccination the disease started after varicella infection.Using complement-fixation (F) test and EIA, antibodies to measles virus (MV) were detected in the CSF and sera of all patients. The CF-antibody titers ranged from 1:1024 to 1:65536 in sera and from 1:16 to 1:128 in CSF samples. MV antigen was detected in brain imprints using IFA in two patients. Electron microscopic analysis revealed intranuclear viral inclusions (MV nucleocapsids). Using RT-PCR, viral RNA was found in both patients. Nucleotide sequence analysis showed that the viruses found in the brain tissue belonged to the wild-type MV D6 genotype [7].

Surveillance of influenza in Croatia is based on notification of disease/death due to communicable diseases that are reported within 24 hours (during the influenza season weekly aggregated reports are submitted) to the Epidemiology Service of the Croatian National Institute of Public Health (CNIPH). Field investigation of each cluster is conducted and samples are sent to the CNIPH National laboratory for influenza. The registered influenza morbidity in Croatia amounts to up to 191,000 cases annually, oscillating, in the interpandemic period, from several thousand to over 190,000. Average annual notification rate during last five years was 168/10000 inhabitants. Based on health service notification in the season 1957/58, Asian influenza pandemic A/Singapore/H2N2 caused illness in more than 500,000 people. The Hong Kong pandemic influenza (A/Hong Kong/H3N2) was registered in Croatia in the 1967/68 and 1969/70 season. Total number of notified influenza cases during that period was 582,000 people (14% of inhabitants). During the Hong Kong influenza pandemic morbidity higher than 1,000/10,000 inhabitants was recorded both in children aged 7?19 years and in persons aged 20+ years. The Preparedness Plan for Pandemic influenza is based on historical morbidity data in previous pandemic influenza outbreaks in the country. The brief overview of preparedness plan was given using the phases of interpandemic and pandemic period according to the latest agreed definitions published by the WHO., Nadzor nad gripom u Hrvatskoj zasniva se na prijavi oboljenja/smrti od zaraznih bolesti o kojima se unutar 24 sata obavještava (tijekom sezone influence tjedno se dostavljaju kumulativna izvješća) Služba za epidemiologiju Hrvatskog zavoda za javno zdravstvo. Provodi se epidemiološki izvid svakog pojedinog grupiranja, a uzorci se šalju Nacionalnom laboratoriju za influencu pri Hrvatskom zavodu za javno zdravstvo. Registrirani morbiditet od influence u Hrvatskoj iznosi 191,000 slučajeva godišnje te oscilira u interpandemijskom periodu od nekoliko tisuća pa do 190,000 slučajeva godišnje. Prosječni broj prijava u posljednjih pet godina iznosi 168 na 10000 stanovnika. Prema prijavama zdravstvenih službi za sezonu 1957/58, pandemija azijske influence A/Singapur/H2N2 uzrokovala je bolest kod više od 500,000 osoba. Pandemija hongkonške inlfuence (A/Hong Kong/H3N2) registrirana je u Hrvatskoj u sezonama 1967./68. i 1969./70. Ukupni broj prijavljenih slučajeva influence tijekom tog perioda iznosio je 582,000 osoba (14% stanovnika). Tijekom pandemije hongkonške influence morbiditet veći od 1,000/10,000 stanovnika zabilježen je u djece starosti od 7-9 godina i u osoba starijih od 20 godina. Plan pripravnosti za pandemijsku influencu zasniva se na povijesnim podacima o morbiditetu prethodnih epidemija influence u zemlji. Kratki pregled plana pripravnosti prikazan je korištenjem faza interpandemijskog i pandemijskog razdoblja u skladu s posljednjim definicijama Svjetske zdravstvene organizacije.

Clinical, epidemiological and laboratory findings of four patients with subacute sclerosing panencephalitis (SSPE), diagnosed in Croatia in 2002, were examined. Patient age at disease onset ranged from 5–11 years. All patients were vaccinated regularly with MMR-vaccine. Two patients had a history of measles infection at the age of six and seven months, respectively. In the other two patients, the disease started immediately after the varicella infection. Complement fixing antibody titre to the measles virus (MV) ranged from 1:1024 to 1:65536 in serum, and from 1:16 to 1:128 in cerebrospinal fluid (CSF). In CSF, no antibodies to varicella-zoster virus were found. Brain tissue samples were obtained at autopsy from two patients. In one patient, electron microscopy demonstrated intranuclear viral inclusions (MV nucleocapsids). MV antigen was detected in brain imprints using IFA in both of them. Viral RNA was found in brain tissue samples only, while plasma, serum and CSF were negative. Nucleotide sequence analysis showed that the viruses detected in brain tissue belong to the wild-type MV D6 genotype14.

Two cases of subacute sclerosing panencephalitis (SSPE), diagnosed in Croatia in 2002, were investigated. The coding regions of the matrix (M), hemagglutinin (H) and nucleoprotein (N) genes of measles virus were sequenced following direct RT-PCR amplification of viral RNA extracted from brain tissue. Phylogenetic analysis of the sequences of H and N genes, showed that both strains belonged to genotype D6. No vaccine strain was detected although both patients had been previously immunized. The comparison of analyzed sequences of two SSPE causative viruses with corresponding sequences of D6 genotype and with each other revealed a number of mutations in N and H gene sequences. In comparison to the Edmonston reference strain, the M gene of the SSPE viruses showed the characteristic biased hypermutation and a premature termination codon in one of the patients.

In an adaptive immune response, antigen is recognized by two distinct sets of highly variable receptor molecules: (1) immunoglobulins, that serve as antigen receptors on B cells and (2) the antigen-specific receptors on T cells. T cells play important role in the control of infection and in the development of protective immunity. These cells can also mediate anti-tumor effects and, in case of autoimmune syndromes, contribute to the development and pathology of disease. The specificity of T cells is determined by T cell receptors (TCR). Understanding of the success of immune responses requires the direct measurement of antigen-specific T lymphocytes. Cell with major histocompatibility complex (MHC) class I molecules are able to present antigens to antigen-specific CD8+ cytotoxic T lymphocytes. MHC class I molecules present small peptides (epitopes) processed from intracellular antigens such as viruses and intracellular bacteria. MHC class I molecules in humans are designated as human leukocyte antigen (HLA) class I and divided into HLA-A, -B and -C. CD8+ T cells recognize MHC class I molecules and after activation produce proteins that destroy infected cells. MHC class II molecules receive their peptides mainly from extracellular and soluble antigens and present them to the CD4+ T helper cells. A recently described technique that can be used in flow cytometry enables us to quantify ex vivo antigen-specific T cells by binding of soluble tetramer MHC-peptide complexes attached to fluorochrome. Quantitative analyses of antigen-specific T cell populations provide important information on the natural course of immune responses. The interaction of T cell receptors on T lymphocytes with tetrameric MHC-peptide complexes mimics the situation on the cell surface, and allows for reliable binding. Tetramers consist of four biotinylated HLA-peptide epitope complexes bound to streptavidin conjugated with fluorescent dye. Tetramer technology has sensitivity of detection as little as 0.02% of total cytotoxic T cell pool or T helper cell pool (i.e. approximately 1 in 50.000 lymphocytes). The combination of this technology with intracellular cytokine staining methods opens up significantly better ways of studying these cells than previously possible, allowing immunologists to look at their life cycle (activation and proliferation), manner of death (aging and apoptosis) and effector function (cytotoxic potential and cytokine production). MHC tetramers class I have yielded useful insights into in vivo dynamic and function of antigen-specific CD8+ T cells in viral infections, parasitic infections, cancer, autoimmune disease and transplantation. This knowledge is of special interest for immunotherapy, diagnostic monitoring of T cell mediated immunity, and the development of new vaccination strategies. There is some possibility for cell therapy with antigen-specific CD8+ T cells for various diseases including cancer and viral infections. Targeted immunotherapy of selective deletion of auto--or alloreactive T cells with MHC tetramers may be important for the treatment of autoimmune disease, or to prevent the rejection of transplanted organs. The utility of this technique for the immunotherapy in vivo needs to be confirmed and modified in further research. Understanding how antigen-specific cells develop and function in different circumstances and pathologies will be the key to unravelling the secrets of cellular immune system.

In the frame of measles elimination activities, sera from 1205 Croatian citizens from all parts of the country and of all ages were tested, using Gull Laboratories ELISA, for measles IgG. Equivocal results were found in 50 subjects. Of the remaining 1155 participants, 118 or 10.2% were negative and 1037 or 89.8% positive. The proportion of seronegatives ranged from zero (age groups 41-50, 51 and more) up to 21.4% (1 year of age). As for their distribution into age groups suggested by the European Regional Office of WHO, there were 12.7, 8.9, 9.5 and 8.8% negatives in age groups 1-4, 5-9, 10-14 and 15 + years, respectively. According to these results, only the first two age groups meet WHO criteria, indicating that vaccination coverage higher than the reported 90-94% should be attained if one is to expect measles elimination.

An outbreak of hepatitis A occurred among children of a refugee camp in Croatia. In order to disrupt the outbreak, we decided to vaccinate children from 1 to 15 years of age in the camp, in addition to intensified general preventive measures. Assuming high prevalence of hepatitis A virus antibodies within this population, we conducted anti-HAV testing of the children eligible for vaccination. Of 108 children tested, 74 (68.5%) were anti-HAV positive. We vaccinated 34 children. One month after vaccination 31 previously negative children were tested for anti-HAV and 30 of them were found positive, suggesting a seroconversion rate of 96.8%. One child fell ill 5 days after vaccination, after whom no new cases of hepatitis A occurred. Thus we conclude that active immunization is a successful means of stopping an outbreak of hepatitis A.

In a Letter to the Editor published in Vaccine recently (Vaccine 24 (2006) 6371-6373), the authors describe clinical features of vaccine associated aseptic meningitis (AM) of patients hospitalized in one hospital, proceeding to calculate incidence rates of AM based on hospital admission data. Since the denominator for hospital-based cases is unknown, the incidence rates calculated in such a way are methodologically incorrect and should not be considered relevant.

Prehrambena i biološka vrijednost mlijeka kao namirnice izuzetno je visoka uzevši u obzir sastav, mogućnost resorpcije i iskorištenja u organizmu. Unatrag nekoliko godina iskustva i stručna saznanja upućuju na zaštitnu ulogu mlijeka i mliječnih proizvoda u sprečavanju nekih kroničnih bolesti kao npr lokalizacije karcinoma, hipertenzije i osteoporoze. Potrošnja pojedinih vrsta mliječnih proizvoda podložna je promjenama i utjecaju novijih saznanja, ekonomskim prilikama i ustaljenim prehrambenim navikama pučanstva. Podaci o prehrambenim navikama i potrošnji mlijeka i mliječnih proizvoda u Hrvatskoj upozoravaju na lagani pad potrošnje mlijeka i mliječnih proizvoda. Rezultati istraživanja koje je proveo Hrvatski zavod za javno zdravstvo upućuju na nezadovoljavajuće nisku potrošnju mlijeka i mliječnih proizvoda u populaciji školske djece osnovnih i srednjih škola u Hrvatskoj. Samo 66 % školske djece dnevno konzumira više od dva decilitra mlijeka, a čak 17 % manje od jednog decilitra. Također, na temelju rezultata analize cjelodnevnih obroka učenika osnovnih škola u Hrvatskoj utvrđeno je da se prosječno vrijednosti kalcija kreću u rasponu od 570 do 713 mg u odnosu na preporučenih 1000 mg. Podaci o potrošnji mlijeka u odrasloj populaciji pokazuju da samo 45 % odraslih osoba svakodnevno konzumira mlijeko., Considering composition, resorption and utilization in organism, milk is qualified as a foodstuff of a high nutrient density. Experience and scientific evidence point that milk contributes to prevention of several chronic illnesses such as some carcinoma sites, hypertension and osteoporosis. Consumption of different types of milk products is influenced by new scientific findings, economical situation and dietary habits. Since several years, data on food consumption confirmed a slight decrease in consumption of milk and milk products. Results of nutrition surveys, conducted by the Croatian National Institute of Public Health also indicate unsatisfactorily low consumption of milk and milk products among elementary and secondary school population in Croatia. Only 66% of school children consume two or more, while 17 % of children consume less than one deciliter of milk daily. According to the results of a whole day meal computer analysis, daily mean values of calcium intake is within range from 570-713 mg in comparision to recommended 1000 mg and more of calcium. Data on milk consumption among adult population point that only about 45 % of adults consume milk every day.

Introduction In July and August 2021, the SARS-CoV-2 Delta variant dominated in Europe. Aim Using a multicentre test-negative study, we measured COVID-19 vaccine effectiveness (VE) against symptomatic infection. Methods Individuals with COVID-19 or acute respiratory symptoms at primary care/community level in 10 European countries were tested for SARS-CoV-2. We measured complete primary course overall VE by vaccine brand and by time since vaccination. Results Overall VE was 74% (95% CI: 69–79), 76% (95% CI: 71–80), 63% (95% CI: 48–75) and 63% (95% CI: 16–83) among those aged 30–44, 45–59, 60–74 and ≥ 75 years, respectively. VE among those aged 30–59 years was 78% (95% CI: 75–81), 66% (95% CI: 58–73), 91% (95% CI: 87–94) and 52% (95% CI: 40–61), for Comirnaty, Vaxzevria, Spikevax and COVID-19 Vaccine Janssen, respectively. VE among people 60 years and older was 67% (95% CI: 52–77), 65% (95% CI: 48–76) and 83% (95% CI: 64–92) for Comirnaty, Vaxzevria and Spikevax, respectively. Comirnaty VE among those aged 30–59 years was 87% (95% CI: 83–89) at 14–29 days and 65% (95% CI: 56–71%) at ≥ 90 days between vaccination and onset of symptoms. Conclusions VE against symptomatic infection with the SARS-CoV-2 Delta variant varied among brands, ranging from 52% to 91%. While some waning of the vaccine effect may be present (sample size limited this analysis to only Comirnaty), protection was 65% at 90 days or more between vaccination and onset.

Krpeljni meningoencefalitis (KME) je rastući javno zdravstveni problem u središnjoj i sjevernoj Europi. Uzročnik infekcije je RNK virus iz porodice Flaviviridae, roda Flavivirus. Danas je poznato 12 vrsta krpeljima prenosivih flavivirusa iz skupine uzročnika meningoencefalitisa. Na temelju domaćina, podijeljeni su na viruse koji inficiraju sisavce i izolate izdvojene iz morskih ptica. Premda se KME sezonski javlja u Republici Hrvatskoj (RH) te svaki slučaj podliježe prijavi Svjetskoj zdravstvenoj organizaciji, primjetan je nedostatak podataka vezanih za identifikaciju mogućih vektora, njihovu rasprostranjenost, kao i prevalenciju uzročnika KME u vektorima i životinjama na području RH. Na području Europe, glavni prijenosnik virusa KME je krpelj Ixodes ricinus koji može invadirati preko 300 različitih vrsta životinja, ali i ljude. Pri tom virus može biti prenošen s krpelja na krpelja transtadijalno, transovarijalno i zajedničkim bliskim hranjenjem inficiranih i primljivih krpelja na istom domaćinu. U ljudi su zabilježeni slučajevi infekcije i putem konzumacije nepasteriziranog kontaminiranog mlijeka. U RH postoji ograničen broj pisanih uradaka o prevalenciji i pojavnosti KME u životinja. Stoga smo s ciljem boljeg epidemiološkog uvida u širenje KME identificirali i utvrdili prevalenciju virusa KME u 371 krpelju (1, 6%) skinutom s lešina 40 lisica (Vulpes vulpes) izlovljenih u endemskim područjima sjeverne Hrvatske, te stekli bolji uvid o ulozi divljih papkara, poglavito jelena običnog (Cervus elaphus) u održavanju virusa KME u prirodnom ciklusu. U istraživanju smo identificirali pet vrsta krpelja (Ixodes ricinus, Ixodes hexagonus, Haemaphysalis punctata, Dermacentor reticulates i Rhipicephalus sanguineus), ali virus smo izdvojili jedino iz odraslih oblika dobro nasisanih krpelja vrsta I. ricinus i I. hexagonus. Nadalje, virus smo dokazali i u slezenama dvaju od 182 pretražena jelena obična (1, 1%). Izolati virusa izdvojeni na području Hrvatske su na temelju nukleotidne i aminokiselinske podudarnosti svrstani u dva klastera europske podskupine virusa što ukazuje na unos i paralelno širenje dvaju genetskih podtipova virusa. Naši rezultati ukazuju na potrebu za prepoznavanjem životinjskih rezervoara KME infekcije u RH te za daljnjom genetskom tipizacijom izolata kako bi utvrdili mogući međuvrsni prijenos virusa. Divlje životinje mogle bi predstavljati idealan sentinel za prepoznavanje endemičnih područja u RH i analizu rizika daljnje pojave i širenja infekcije.

Krpeljni meningoencephalitis (KME) je rastući javno zdravstveni problem u središnjoj i sjevernoj Europi. Uzročnik infekcije je RNK virus iz porodice Flaviviridae, roda Flavivirus. Danas je poznato 12 vrsta krpeljno prenosivih flavivirusa iz skupine uzročnika meningoencefalitisa. Na temelju domaćina, podijeljeni su na viruse koji inficiraju sisavce i izolate izdvojene iz morskih ptica. Premda se KME sezonski javlja u Republici Hrvatskoj (RH) te svaki slučaj podliježe prijavi svjetskoj zdravstvenoj organizaciji, primjetan je nedostatak podataka vezanih za identifikaciju mogućih vektora, njihovu rasprostranjenost, kao i prevalenciju uzročnika KME u vektorima i životinjama na području RH. Na području Europe, glavni prijenosnik virusa KME je krpelj Ixodes ricinus koji može invadirati preko 300 različitih vrsta životinja, ali i ljude. Pri tom virus može biti prenošen s krpelja na krpelj transtadijalno, transovarijalno i zajedničkim bliskim hranjenjem inficiranih i primljivih krpelja na istom domaćinu. U ljudi su zabilježeni slučajevi infekcije i putem konzumacije nepasteriziranog kontaminiranog mlijeka. U RH postoji ograničen broj pisanih uradaka o prevalenciji i pojavnosti KME u životinja. Stoga smo s ciljem boljeg epidemiološkog uvida u širenje KME identificirali i utvrdili prevalenciju virusa KME u 371 krpelju (1.6%) skinutima s lešina 40 lisica (Vulpes vulpes) izlovljenih u endemskim područjima sjeverne Hrvatske, te stekli bolji uvid o ulozi divljih papkara, poglavito jelena običnog (Cervus elaphus) u održavanju virusa KME u prirodnom ciklusu. U istraživanju smo identificirali pet vrsta krpelja (Ixodes ricinus, Ixodes hexagonus, Haemaphysalis punctata, Dermacentor reticulates i Rhipicephalus sanguineus), ali virus smo izdvojili jedino iz odraslih oblika dobro nasisanih krpelja vrsta I. ricinus i I. hexagonus. Nadalje, virus smo dokazali i u slezenama dvaju od 182 pretražena jelena obična (1.1%). Izolati virusa izdvojeni na području Hrvatske su na temelju nukleotidne i aminokiselinske podudarnosti svrstani u dva klastera Europske podskupine virusa što ukazuje na unos i paralelno širenje dvaju genetskih podtipova virusa. Naši rezultati ukazuju na potrebu za prepoznavanjem životinjskih rezervoara KME infekcije u RH te za daljnjom genetskom tipizacijom izolata kako bi utvrdili mogući međuvrsni prijenos virusa. Divlje životinje mogle bi predstavljati idealan sentinel za prepoznavanje endemičnih područja u RH i analizu rizika daljnje pojave i širenja infekcije.