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West Nile virus (WNV) danas je jedan od najrasprostranjenijih arbovirusa. U posljednja se dva desetljeća WNV infekcije kontinuirano pojavljuju na području Europe u obliku manjih ili većih epidemija i epizootija. U ovom preglednom radu prikazujemo epidemiološke značajke WNV infekcija koje su dokazane na području Hrvatske i Srbije u kontekstu “Jednog zdravlja”. Prikazani rezultati potvrđuju značaj multidisciplinarne i regionalne suradnje u dijagnostici i praćenju ove (re-)emergentne virusne zoonoze.

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.

Lymphocytic choriomeningitis virus (LCMV) is a neglected human pathogen associated with aseptic meningitis, severe systemic infections in immunocompromised persons, and congenital anomalies. Data on the prevalence of LCMV infections are scarce. We analyzed the seroprevalence of LCMV in continental Croatian regions. A total of 338 serum samples of professionally exposed (forestry workers, hunters, agriculture workers in contact with rodents) and non-exposed populations (general population, pregnant women) were tested for the presence of LCMV antibodies using indirect immunofluorescence assay. No participants reported recent febrile disease. LCMV IgG antibodies were detected in 23/6.8% of participants: 9.8% exposed persons and 5.1% non-exposed persons (6.1% in the general population and 3.9% in pregnant women). No participants were LCMV IgM positive. Although higher seropositivity was found in males compared to females (8.9% vs. 4.7%), inhabitants of suburban/rural areas compared to inhabitants of urban areas (9.2% vs. 4.6%), and persons who used well as a source of water compared to those who used tap (11.4% vs. 5.6%), these differences did not reach statistical significance. Results of logistic regression showed that the presence of rodents in the house/yard and cleaning rodent nests were associated with an elevated risk for LCMV infection (OR = 2.962, 95% CI = 1.019–8.607).

Several arboviruses have emerged in Croatia in recent years. Tick-borne encephalitis is endemic in continental counties; however, new natural micro-foci have been detected. Two autochthonous dengue cases were reported in 2010. West Nile virus emerged in 2012, followed by emergence of Usutu virus in 2013. Although high seroprevalence rates of Toscana virus have been detected among residents of Croatian littoral, the virus remains neglected, with only a few clinical cases of neuroinvasive infections reported. Lymphocytic choriomeningitis virus is a neglected neuroinvasive rodent-borne virus. So far, there are no reports on human clinical cases; however, the seroprevalence studies indicate the virus presence in the Croatian mainland. Puumala and Dobrava hantaviruses are widely distributing rodent-borne viruses with sporadic and epidemic occurrence. Hepatitis E virus is an emerging food-borne virus in Croatia. After the emergence in 2012, cases were regularly recorded. Seropositivity varies greatly by region and population group. Rotaviruses represent a significant healthcare burden since rotavirus vaccination is not included in the Croatian national immunization program. Additionally, rotaviruses are widely distributed in the Croatian ecosystem. A novel coronavirus, SARS-CoV-2, emerged in February 2020 and spread rapidly throughout the country. This review focuses on emerging and neglected viruses of zoonotic importance detected in Croatia.

Floods can pose a number of safety and health hazards for flood-affected populations and rescuers and bring risk of injuries, infections, and diseases due to exposure to pathogenic microorganisms and different biological and chemical contaminants. The risk factors and possible health consequences for the rescuers involved in evacuation and rescuing operations during the May 2014 flood crisis in Croatia are shown, as well as measures for the prevention of injuries and illnesses. In cases of extreme floods, divers play a particularly important role in rescuing and first-response activities. Rescuing in contaminated floodwaters means that the used equipment such as diving suits should be disinfected afterwards. The need for securing the implementation of minimal health and safety measures for involved rescuers is paramount. Data regarding injuries and disease occurrences among rescuers are relatively scarce, indicating the need for medical surveillance systems that would monitor and record all injuries and disease occurrences among rescuers in order to ensure sound epidemiological data. The harmful effects of flooding can be reduced by legislation, improvement of flood forecasting, establishing early warning systems, and appropriate planning and education.

Hepatitis E (HE) is an emerging public health problem in developed countries worldwide. Nowadays, it is known that the hepatitis E virus (HEV) has zoonotic potential, whereas domestic pigs and wild boars are recognized as the true reservoirs of the disease. Therefore, the aim of our study was to define the seroprevalence and viral persistence of HEV in pigs and wild boars in Croatia. In total, 1424 samples originating from domestic pigs from 14 counties, and 1000 samples of wild boar origin, collected from 16 counties, were tested during 2016 for the presence of HEV antibodies using a commercially available enzyme linked immunosorbent assay (ELISA). All positive samples, as well as samples originating from in-contact domestic pigs and wild boars, were further tested for the presence of HEV RNA using a real time RT -PCR protocol, followed by a nested RT-PCR protocol as a confirmatory test. In 11 of 14 counties, 469 seropositive domestic pigs were found with an overall seroprevalence of 32.94% (95% CI 30.55-35.42), ranging from 8.33% to 60.00%, depending on their geographical origin. Seropositive wild boars were found in six out of 16 counties, showing an overall seroprevalence of 31.10% (95%CI 28.31-34.04%), ranging from 7.70% to 50.60%. The highest seroprevalence was found in the Vukovar-Srijem and Osijek-Baranja Counties (North-East Croatia) where pig breeding dominates and the highest density of wild boars is recorded. While no positive HEV RNA samples were detected in tested domestic pigs, seventeen serologically positive wild boars (11.33% ; 95%CI 7.19-17.14) younger than one year of age were found to be HEV RNA positive, indicating chronic infection and possible prolonged virus spread into the environment. The detected viral presence despite the immune response indicates that wild boars have a key role in HEV epidemiology