Tick-borne encephalitis in patients vaccinated against this disease.

BACKGROUND: Information on tick-borne encephalitis (TBE) in patients already vaccinated against the disease is limited. OBJECTIVES: To compare the course and outcome in patients with vaccination breakthrough TBE with findings in patients who developed TBE without previous vaccination. METHODS: All adult patients diagnosed with TBE at a single medical centre during a 16-year period and who had received at least two doses of TBE vaccine before the onset of illness qualified for the study. For each patient with breakthrough TBE, two unvaccinated sex- and age-matched patients, diagnosed with TBE in the same year, were included for comparison. RESULTS: Amongst 2332 patients diagnosed with TBE in the period 2000-2015, 39 (1.7%) had been vaccinated against the disease. Their median age was 59 (20-83) years; 22 of 39 (56.4%) were male. In comparison with unvaccinated patients with TBE, those with breakthrough disease more often experienced a monophasic course of illness (P = 0.006), had a higher CSF leucocyte count (P = 0.005), more often had urine retention (P = 0.012), more often needed ICU treatment (P = 0.009), were hospitalized for longer (P = 0.002) and had more severe acute illness (P = 0.004 for simple clinical assessment, P = 0.001 for severity score). CONCLUSION: In addition to several findings corroborating previous results in patients with vaccination breakthrough TBE, such as older age and the presence of a particular specific serum antibody pattern indicating anamnestic response, findings in this study indicate that the acute illness in patients with breakthrough TBE is more severe than in unvaccinated sex- and age-matched patients who develop the disease.

Factors affecting the ecology of tick-borne encephalitis in Slovenia.

Recognition of factors that influence the formation of tick-borne encephalitis (TBE) foci is important for assessing the risk of humans acquiring the viral infection and for establishing what can be done (within reasonable boundaries) to minimize that risk. In Slovenia, the dynamics of the TBE vector, i.e. Ixodes ricinus, was studied over a 4-year period and the prevalence of infection in ticks was established. Two groups of tick hosts were investigated: deer and small mammals. Red deer have been confirmed as having a direct influence on the incidence of TBE and rodents have been recognized as important sentinels for TBE infections, although their role in the enzootic cycle of the virus still remains to be elucidated. Last, forest and agricultural areas, which are influenced by human activity, are suitable habitats for ticks, and important for TBEV transmission and establishment. Human behaviour is also therefore an important factor and should always be considered in studies of TBE ecology.

Autochthonous dengue fever in Croatia, August-September 2010.

After information about a dengue case in Germany acquired in Croatia, health professionals and the public in Croatia were alerted to assess the situation and to enhance mosquito control, resulting in the diagnosis of a second case of autochthonous dengue fever in the same area and the detection of 15 persons with evidence of recent dengue infection. Mosquito control measures were introduced. The circumstances of dengue virus introduction to Croatia remain unresolved.

A five-year perspective on the situation of haemorrhagic fever with renal syndrome and status of the hantavirus reservoirs in Europe, 2005-2010.

Hantavirus infections are reported from many countries in Europe and with highly variable annual case numbers. In 2010, more than 2,000 human cases were reported in Germany, and numbers above the baseline have also been registered in other European countries. Depending on the virus type human infections are characterised by mild to severe forms of haemorrhagic fever with renal syndrome. The member laboratories of the European Network for diagnostics of Imported Viral Diseases present here an overview of the progression of human cases in the period from 2005 to 2010. Further we provide an update on the available diagnostic methods and endemic regions in their countries, with an emphasis on occurring virus types and reservoirs.

Low prevalence of active COVID-19 in Slovenia: a nationwide population study of a probability-based sample.

OBJECTIVES: Accurate population-level assessment of the coronavirus disease 2019 (COVID-19) burden is fundamental for navigating the path forward during the ongoing pandemic, but current knowledge is scant. We conducted the first nationwide population study using a probability-based sample to assess active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, combined with a longitudinal follow-up of the entire cohort over the next 6 months. Baseline SARS-CoV-2 RNA testing results and the first 3-week follow-up results are presented. METHODS: A probability-based sample of the Slovenian population comprising data from 2.1 million people was selected from the Central Population Register (n = 3000). SARS-CoV-2 RNA was detected in nasopharyngeal samples using the cobas 6800 SARS-CoV-2 assay. Each participant filled in a detailed baseline questionnaire with basic sociodemographic data and detailed medical history compatible with COVID-19. After 3 weeks, participants were interviewed for the presence of COVID-19-compatible clinical symptoms and signs, including in household members, and offered immediate testing for SARS-CoV-2 RNA if indicated. RESULTS: A total of 1368 individuals (46%) consented to participate and completed the questionnaire. Two of 1366 participants tested positive for SARS-CoV-2 RNA (prevalence 0.15%; posterior mean 0.18%, 95% Bayesian confidence interval 0.03-0.47; 95% highest density region (HDR) 0.01-0.41). No newly diagnosed infections occurred in the cohort during the first 3-week follow-up round. CONCLUSIONS: The low prevalence of active COVID-19 infections found in this study accurately predicted the dynamics of the epidemic in Slovenia over the subsequent month. Properly designed and timely executed studies using probability-based samples combined with routine target-testing figures provide reliable data that can be used to make informed decisions on relaxing or strengthening disease mitigation strategies.

Hantavirus infections.

Over the past few decades understanding and recognition of hantavirus infection has greatly improved worldwide, but both the amplitude and the magnitude of hantavirus outbreaks have been increasing. Several novel hantaviruses with unknown pathogenic potential have been identified in a variety of insectivore hosts. With the new hosts, new geographical distributions of hantaviruses have also been discovered and several new species were found in Africa. Hantavirus infection in humans can result in two clinical syndromes: haemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS) caused by Old World and New World hantaviruses, respectively. The clinical presentation of HFRS varies from subclinical, mild, and moderate to severe, depending in part on the causative agent of the disease. In general, HFRS caused by Hantaan virus, Amur virus and Dobrava virus are more severe with mortality rates from 5 to 15%, whereas Seoul virus causes moderate and Puumala virus and Saaremaa virus cause mild forms of disease with mortality rates <1%. The central phenomena behind the pathogenesis of both HFRS and HCPS are increased vascular permeability and acute thrombocytopenia. The pathogenesis is likely to be a complex multifactorial process that includes contributions from immune responses, platelet dysfunction and the deregulation of endothelial cell barrier functions. Also a genetic predisposition, related to HLA type, seems to be important for the severity of the disease. As there is no effective treatment or vaccine approved for use in the USA and Europe, public awareness and precautionary measures are the only ways to minimize the risk of hantavirus disease.

The European Virus Archive goes global: A growing resource for research.

The European Virus Archive (EVA) was created in 2008 with funding from the FP7-EU Infrastructure Programme, in response to the need for a coordinated and readily accessible collection of viruses that could be made available to academia, public health organisations and industry. Within three years, it developed from a consortium of nine European laboratories to encompass associated partners in Africa, Russia, China, Turkey, Germany and Italy. In 2014, the H2020 Research and Innovation Framework Programme (INFRAS projects) provided support for the transformation of the EVA from a European to a global organization (EVAg). The EVAg now operates as a non-profit consortium, with 26 partners and 20 associated partners from 21 EU and non-EU countries. In this paper, we outline the structure, management and goals of the EVAg, to bring to the attention of researchers the wealth of products it can provide and to illustrate how end-users can gain access to these resources. Organisations or individuals who would like to be considered as contributors are invited to contact the EVAg coordinator, Jean-Louis Romette, at jean-louis.romette@univmed.fr.

Spatial and temporal dynamics of Puumala hantavirus infection in red bank vole (Clethrionomys glareolus) populations in Belgium.

Dynamics of hantavirus infection and population densities in rodents were investigated from 1996 to 1999 in southern Belgium. Evidence of Puumala infection was restricted to Clethrionomys glareolus. Although the serotype was not determined, antibodies against hantavirus were also found in eight Apodemus sylvaticus. In fall 1996, the seroprevalence in C. glareolus was high (20.1%, 37 of 184) and the infection was widely distributed in the area studied whereas a focal occurrence of positive rodents and lower seroprevalence rates were recorded in spring 1997 (14.3%, six of 42), fall 1997 (6. 6%, 11 of 166), spring 1998 (6.4%, three of 47) and fall 1998 (6.7%, 11 of 165). A pullulation of rodents was observed in spring 1999 and was associated with a markedly higher seroprevalence in C. glareolus (47.7%, 189 of 396). In all seasons, infection rates in adults were higher than in juveniles and subadults. No significant difference of prevalence was recorded between males and females. In two trapping sites, the temporary disappearance of positive animals after a crash in rodent populations suggests that a threshold in density is necessary for the maintenance of the enzootic cycle.

Evaluation of two commercially available immunoassays for the detection of hantavirus antibodies in serum samples.

BACKGROUND: hantaviruses are members of the family Bunyaviridae and the spectrum of clinical symptoms in humans may vary from sub-clinical to severe haemorrhagic fever with renal syndrome (HFRS) or pulmonary syndrome (HPS). Several serotypes have been described from which at least five are pathogenic to humans. Each serotype has a different animal reservoir and geographical distribution. In the acute phase of the disease the clinical diagnosis may be confirmed by serology or by polymerase-chain reaction (PCR). OBJECTIVE: to evaluate two commercially available immunoassays using sera from hantavirus suspected and non-hantavirus patients: an enzyme immunoassay (EIA) developed by MRL Diagnostics, for the detection of immunoglobulins M (IgM) and G (IgG) against several hantavirus serotypes and an indirect immunofluorescence assay (IFA) from Progen, based on slides coated with Hantaan virus (HNTV) and Puumala virus (PUUV), infected cells. STUDY DESIGN: a total of 145 serum samples were used for this study. The serum panel included serum samples from patients suspected of mild (n=91), severe (n=10) HFRS and patients with other viral infections (n=44). RESULTS: the agreement between the MRL EIA and the Progen IFA for the detection of IgM and IgG serum antibodies ranged from 87 to 91%, respectively. In the non-hantavirus group one out of 44 samples was positive by the Progen HNTV IgM IFA, none in the Progen PUUV IFA and two samples in the MRL IgM EIA, resulting in specificities of 98, 100 and 95%, respectively. The sensitivities and specificities of the MRL EIAs compared to the Progen overall PUUV and HNTV IFAs were 90 and 91% for IgM, respectively, and 96% for IgG in both immunoassays. CONCLUSIONS: the MRL EIA proved to be relatively sensitive and specific assay for the serological diagnosis of mild and severe HFRS.

Isolation of a strain of a Hantaan virus from a fatal case of hemorrhagic fever with renal syndrome in Slovenia.

Hemorrhagic fever with renal syndrome (HFRS) has been serologically confirmed in Slovenia during the last seven years. There is evidence that three hantaviruses (Hantaan, Puumala, and a newly described form termed Dobrava) circulate simultaneously in this area. Recently, a hantavirus was isolated from the urine and brain tissue of a fatal case of HFRS. Positive immunofluorescent reactions with reference human sera and monoclonal antibodies were first recognized after the second cell culture passage. Extensive cross-reactivity between our isolate and prototype Hantaan virus, strain 76-118, and Hantaan-like isolates from the former Yugoslavia, Fojnica and Plitvice, was revealed by enzyme-linked immunosorbent assay with specific rat antisera. The reaction pattern of the isolate was similar to the prototype Hantaan virus by indirect immunofluorescent assay with a panel of monoclonal antibodies. Furthermore, the specificity of the isolates was confirmed by analysis of polymerase chain reaction products of this virus with five restriction endonucleases. This appears to be the first isolation of a strain of prototype Hantaan virus from a fatal case of HFRS in Europe.

Clinical distinction between human granulocytic ehrlichiosis and the initial phase of tick-borne encephalitis.

OBJECTIVES: The aim of our study was to establish clinical and laboratory differences between patients with acute human granulocytic ehrlichiosis (HGE) and patients with the initial phase of tick-borne encephalitis (TBE). METHODS: Clinical features and laboratory results of four patients with acute HGE (established by the presence of the specific DNA sequences of the HGE agent in whole blood by polymerase chain reaction and/or by seroconversion to the HGE agent by indirect immunofluorescence assay) and 12 patients with the initial phase of TBE (demonstrated by the presence of serum IgM antibodies to TBE virus) were compared. All these patients were uncovered at the Department of Infectious Diseases, University Medical Centre, Ljubljana, Slovenia, during 1995-1996, in a prospective study on the aetiology of febrile illnesses occurring within 6 weeks after a tick bite. RESULTS: Findings were similar for the majority of the examined parameters including severity of illness, level and duration of fever, presence of headache, leukopenia, thrombocytopenia, and liver - function test abnormalities. Statistically significant differences were found only for arthralgia (P=0.026) and elevated concentration of C-reactive protein (P=0.003); both variables were found more often in patients with acute HGE. CONCLUSIONS: In a patient residing in the central part of Slovenia, who reports a tick bite followed by a febrile illness with leukopenia and/or thrombocytopenia, the presence of arthralgias and/or an elevated C-reactive protein value directs toward the diagnosis of acute HGE and against the initial phase of TBE.

Seroprevalence of ehrlichiosis, Lyme borreliosis and tick-borne encephalitis infections in children and young adults in Slovenia.

BACKGROUND: Little is known about the seroprevalence of ehrlichiosis in adults and much less about the same in children. METHODS: One hundred and forty-three healthy children and young adults (6-24 years of age, male to female ratio, 1:1) were assessed for the presence of antibodies to the agents of human granulocytic ehrlichiosis (HGE), human monocytic ehrlichiosis (HME), Borrelia burgdorferi sensu stricto (BB), and tick-borne encephalitis (TBE) virus in Slovenia, where tick-related infections are endemic. Antibodies to HGE and HME agents were assayed by indirect immunofluorescence, and antibodies to BB and TBE by enzyme-linked immunosorbent assay. A questionnaire about tick exposure was answered by all subjects. In the event of a positive result, a detailed interview was conducted. RESULTS: Of 143 study subjects, 22 (15.4%) had detectable antibodies to HGE agent, 22 (15.4%) were positive to BB, 18 (12.6%) were positive to TBE virus (12 of these were vaccinated) and 4 (2.8%) were positive to the HME agent. The history of persons seropositive to an HGE agent had been uneventful. CONCLUSIONS: Our study documents a high seroprevalence of HGE in children and young adults in Slovenia, similar to the seroprevalence of LB and higher than that of TBE and HME. Although the majority of these infections are probably asymptomatic or mild, active surveillance for acute HGE infections in children in areas endemic for tick-related infections is necessary.

Diffuse reversible alopecia in patients with Lyme meningitis and tick-borne encephalitis.

Alopecia occurring after febrile bacterial and viral infection is a phenomenon well known since the beginning of the century. To evaluate the occurrence of alopecia in tick transmitted disease, 23 adult patients with Lyme meningitis and 71 patients with tick-borne encephalitis were included in a prospective study and were followed up for one year. Diffuse alopecia occurred within three months after the outbreak of disease in 3 out of 23 (13%) patients with Lyme meningitis and in 40 out of 71 (56.3%) patients with tick-borne encephalitis. The mean duration of alopecia was 2 to 3 months and alopecia was reversible in all patients.

Infection of small mammals with Borrelia burgdorferi sensu lato in Slovenia as determined by polymerase chain reaction (PCR).

Thirty-four small mammals collected in the vicinity of Ljubljana were tested for the presence of Borrelia burgdorferi sensu lato by polymerase chain reaction (PCR) of urinary bladder tissues, using universal flagellin primers and species specific rRNA primers. Seventeen small mammals (50%) were found to be positive, and 7 small mammals were infected with two species of B. burgdorferi sensu lato simultaneously. The most commonly found species was B. afzelii (n = 14), followed by B. burgdorferi sensu stricto (n = 7) and B. garinii (n = 3), as determined by species-specific primers. We conclude that PCR is a rapid and reliable method to detect infection with B. burgdorferi sensu lato in small mammals.

Human ehrlichiosis in central Europe.

Ehrlichioses are tick-transmitted diseases associated with illnesses of animals for decades, but recently recognised to be emerging human diseases. In the last ten years increasing number of cases of human infections caused by Ehrlichia chaffeensis and granulo-cytic ehrlichia were described in the United States. Several reports also indicate the presence of infection with the human granulocytic ehrlichiosis (HGE) agent in Europe. The first confirmed acute human disease caused by HGE agent was reported from Slovenia. Until 1997, five patients have been discovered in a prospective study on the etiology of febrile illnesses occurring within six weeks following a tick bite, conducted at the Department of Infectious Diseases, University Medical Centre, Ljubljana, Slovenia. The diagnosis of acute HGE was established by seroconversion to the HGE agent and/or molecular identification of ehrlichial organisms. None of the patients had detectable morulae on blood smear examination. Clinical characteristics and laboratory findings were similar to those reported from the United States, although the disease course was relatively mild in the Slovenian cases. All patients recovered rapidly and without sequelae, although only three patients received antibiotic therapy (of whom only two were treated with doxycycline). Many ehrlichiosis cases could go undetected due to a lack of physician awareness, lack of public knowledge, or limited investigation. HGE should now be also included in the differential diagnosis of febrile illnesses occurring after a tick bite in Europe.

Evidence for Hantavirus disease in Slovenia, Yugoslavia.

In Slovenia, North-Western part of Yugoslavia, 17 clinically documented Hantavirus disease cases (HVD) were serologically confirmed so far. Previously HVD was reported in the Southern part of Yugoslavia. By the indirect fluorescent antibody test (IFA), the prevalence of IgG class antibodies against different Hantaviral antigens was demonstrated in human sera collected in Slovenia. Three different reactivity patterns were observed. Majority of the IFA-positive human sera were confirmed by the immunoblot method. The distribution of Hantaviral infections was examined in small mammals captured in two natural foci of HVD, where clinical documented cases were reported. Hantaviral antibodies and antigens were demonstrated in C. glareolus, A. flavicollis, A. sylvaticus, and M. musculus.

The first fatal case of Mediterranean spotted fever in Croatia.

The first lethal case of Mediterranean spotted fever in Croatia is described. A previously healthy, 58-year-old man was admitted to the hospital with high fever and rash. Several days later, severe anemia, leukopenia and thrombocytopenia developed, and the patient died about eight weeks after the onset of disease. Bone marrow biopsy showed hypercellularity of the cortical and trabecular bone structures with morphologically normal cells of all three hematopoietic lineages that were reduced due to regular nodular infiltrates. Serologic findings indicated that Rickettsia conorii infection was the etiologic cause of the patient's death.

[Bartonella henselae as the causative agent in cat-scratch disease: case report]. / Bartonella henselae kao uzrocni agens bolesti macjeg ogreba: prikaz bolesnika.

In this article we reported typical clinical, primary skin lesion and regional lymphadenitis, and atypical, protracted fever and algic syndrome, characteristics of cat scratch disease (CSD) in a 21-year-old man (a student) from Zadar, Croatia. Laboratory parameters were in normal range. The histopathologic findings of affected lymph nodes included stellate caseating granulomas. By using IFA method a seroconversion of specific IgG antibodies (neg/1:512) and rise of IgM antibodies (1:160/ > 1:320) to B. henselae were detected in paired sera, and these serologic findings indicate on conclusion that B. henselae is probably etiologic agent of CSD in our patient.

[Azithromycin in the prevention of Mediterranean spotted fever]. / Azitromicin u profilaksi mediteranske pjegave groznice.

Antibodies to Rickettsia conorii were detected by the indirect immunofluorescence (IFA) assay in 64 (51.6%) out of 124 examinees living in North Dalmatia (Croatia) who had a history of recent tick bites during 1994 and 1995. Positive titers of IFA antibodies to R. conorii were detected in 12 (31.5%) out of 38 examinees with carried out prophylaxis by azithromycin. The usual clinical signs of Mediterranean spotted fever were registered in 22 (25.6%) and asymptomatic infection in 30 (34.8%) out of 86 examinees without prophylaxis. Clinical signs of the disease were not registered in examinees with prophylaxis.