West Nile fever - autochthonous human cases in South Moravia in 2018 from the epidemiological perspective.

AIM: To analyse repeated detection of West Nile virus (WNV) in mosquitoes in South Moravia in correlation with the first documented autochthonous human cases of West Nile fever (WNF), focusing on epidemiological and environmental investigation. MATERIALS AND METHODS: Here we report case studies of five patients with autochthonous WNF without any travel history diagnosed in South Moravia in 2018, along with in-depth epidemiological and environmental investigation. The cases were classified as confirmed based on the case definition criteria established in Commission Implementing Decision (EU) 2018/945. RESULTS: Between July and September 2018, a total of five human cases of West Nile virus infection were suspected and subsequently confirmed by the National Reference Laboratory for Arboviruses in Ostrava. All mosquito suspensions from the area where the first case of WNV infection was diagnosed tested WNV negative. CONCLUSIONS: WNV circulation in South Moravia has been known since 1997 when the first human cases (probably caused by WNV lineage 1) were confirmed after floods. The presence of more serious neuroinvasive lineage 2 (WNV-2), now circulating in central and eastern Europe, was detected repeatedly in 2013, 2015, and 2016 in Cx. modestus and Cx. pipiens mosquitoes within the scope of targeted entomological surveillance. These findings were published in 2016-2018 in both the professional press and mass media. It was only a matter of time and of making the correct differential diagnosis in patients with non-specific neuroinfections before there were confirmed autochthonous human cases of WNF caused by WNV-2. These presumptions were corroborated by epidemiological investigations performed by the staff of the Regional Public Health Authority of the South Moravian Region and Academy of Sciences.

[Hantavirus causing fatal haemorrhagic fever in the Czech Republic]. / Hantavirus jako puvodce smrtelné hemoragické horecky v Ceské republice.

Hantaviruses are RNA viruses of the family Bunyaviridae. Their hosts are mammals of the orders rodents (voles, rats, mice), insectivores (shrews, moles), and chiroptera (bats). Hantaviruses are present in many areas of Europe, the Americas, Asia, and Africa. In the Czech Republic, the occurrence of five species of hantaviruses has been reported (Dobrava/Belgrade, Puumala, Tula, Seewis, and Asikkala), with the first three of them causing human diseases. Although the course of hantavirus infections can be very serious, there is a low awareness of these diseases, even among health professionals, and hantavirus is often not considered in the diagnosis. A case history is reported of a patient who developed hantavirus haemorrhagic fever with renal syndrome (HFRS) with fatal outcome. The patient presented with typical clinical signs, but the correct diagnosis was only made at post mortem.

[Surveillance of West Nile fever in horses in the Czech Republic from 2011 to 2013]. / Surveillance západonilské horecky u koní v Ceské republice v letech 2011-2013.

STUDY AIM: The West Nile virus (WNV) is an important mosquito-borne flavivirus occurring around the world. Occasionally found in Central Europe, the virus spread massively through whole Hungary between 2008 and 2009. The aim of our study was to determine the recent prevalence of the WNV infection in horses in the Czech Republic. MATERIAL AND METHODS: Overall, 2349 serum samples, collected from healthy unvaccinated adult horses in the Czech Republic between 2011 and 2013, were tested. A commercially available competitive ELISA kit (cELISA) was used for this purpose and positive samples were confirmed by virus neutralisation tests using WNV and tick-borne encephalitis virus (TBEV). RESULTS: Altogether 271 of 2348 samples (11.5%) were positive by cELISA. Confirmatory VNT revealed 16 WNV positive samples, 11 of which had titres from 8 to 1024; VNTs with TBEV were negative. Three samples had antibodies against both viruses and the WNV antibody titres were less than or equal to the TBEV antibody titres. A cross reactivity of flaviviruses might have had an impact on the results, but in samples with similar WNV and TBEV titres, co-infection with both pathogens cannot be ruled out either. VNT antibody titres in two horses were inconclusive (cut-off titre 4). The place of birth and transfers (if any) were checked for each WNV seropositive horse. Five WNV positive/TBEV negative samples (0.2%) came from five administrative regions (South Bohemian, Karlovy Vary, Central Bohemian, South Moravian, and Moravian-Silesian) and the respective animals were never moved to a foreign country. Four of these horses never left the farm. Other six WNV positive/TBEV negative horses were imported to the Czech Republic from North America or Central and West Europe and therefore, it is not possible to tell unambiguously whether their infection is autochthonous or imported. CONCLUSION: The results of the present study confirm that WNV antibodies occur sporadically in horses in the Czech Republic. WNV was found to circulate in different parts of the Czech Republic and not only in the South of Moravia.

[Meningoencephalitis caused by Toscana virus in Czech travelers returning from the Mediterranean]. / Meningoencefalitidy zpusobené virem Toscana u ceských cestovatelu po návratu ze Stredomorí.

Presented are case studies of 3 patients with aseptic meninogencephalitis occurring after returning from the Mediterranean tourist regions. None of the infectious agents common in aseptic neuroinfections in the Czech Republic was detected in the patients. Serological tests showed that in each case, the illness was caused by Toscana virus, a phlebovirus belonging to the family Bunyaviridae. The virus is transmitted by tiny biting insects of the genus Phlebotomus commonly present in the Mediterranean area. The course of the disease was mild to moderate and all the patients recovered without sequelae. These case reports document the fact that this arbovirus should be considered in the differential diagnosis of patients with aseptic neuroinfections returning from endemic areas of this virus.

[Evaluation of prophylactic precautions after exposure to biological materials]. / Hodnocení profylaktických opatrení po expozici biologickému materiálu.

OBJECTIVES: Study of transmission rates of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) and effect of HBV vaccination after parenteral exposure to biological materials. PATIENTS AND METHODS: This was a retrospective study of 879 individuals (419 health care professionals and 460 persons from the general population) after blood and body fluid exposure examined at the Clinic of Infectious Diseases in Ostrava from 1999 to 2013. HBsAg, anti-HBs, anti-HBc, anti-HCV, anti-HIV, bilirubin, and ALT were tested in exposed patients and known sources at the baseline and, except anti-HBc, after 3, 6, and 12 months. Susceptible persons were vaccinated against HBV and screened for anti-HBs after 1-2 months. Antiretroviral prophylaxis was provided if reasonable. RESULTS: At the baseline, 42 exposed persons were HBV positive, six were HCV positive, and none was HIV positive. During the follow-up, no new HBsAg positivity was detected in exposed individuals, although 25 of 837 susceptible persons were exposed to HBsAg-positive sources. After vaccination, protective anti-HBs were detected in 707 (84.7%) of 837 susceptible persons and in 709 (97.8%) of 725 persons with known post-vaccination response. Fifty-six of 873 persons had been exposed to HCV-positive sources and HCV transmission was shown in three (two health care professionals) of them. No HIV transmission was observed, although 11 of 879 individuals had been exposed to HIV-positive sources, with antiretroviral prophylaxis provided to nine of them. CONCLUSIONS: Contemporary post-exposure prophylactic precautions in the Czech Republic can be considered as adequate for the prevention of HBV and HIV, but health care professionals in particular are at risk of HCV transmission.

Molecular characterization of dengue virus 1 from autochthonous dengue fever cases in Croatia.

In the summer of 2010, two autochthonous dengue fever cases were detected in Croatia. Here we report the retrospective detection of an additional case of dengue fever, representing the first sustained autochthonous transmission in Europe since 1928. In addition, we present the phylogenetic analyses based on two sequences from the Peljesac peninsula, southern Croatia. The sequences were identified as dengue virus genotype 1 and recovered from two out of the three Peljesac patients in whom infection occurred.

[The use of electron microscopy and virus isolation in the diagnosis of aseptic neuroinfections]. / Vyuzití elektronové mikroskopie a izolace viru v diagnostice aseptických neuroinfekcí.

OBJECTIVE: In aseptic neuroinfections, the etiology is usually known in 50-70% of cases. The aim was to increase the rates using electron microscopy (EM) and virus isolation in cell cultures. MATERIAL AND METHODS: The prospective study included 34 patients with aseptic neuroinfections hospitalized at the Department of Infectious Diseases in Ostrava fromJuly to November 2012. EM examined cerebrospinal fluid of all patients and virus isolation in tissue cultures was performed in all cerebrospinal fluid samples. Cerebrospinal fluid was examined by polymerase chain reaction for enteroviruses in 30 patients and for herpes simplex virus 1 and 2 in 29 patients. Detection of antibodies against Borrelia burgdorferi and tick-borne encephalitis was performed in all 34 patients. RESULTS: Possible etiological agents were discovered in 31 out of 34 patients (91%), with one agent being found in 23 patients (68%) and two agents being detected in 8 patients (24%). EM revealed the agents in 26 patients and virus isolation was successful in 10 patients. EM was the only method to identify 10 agents. A group of 23 patients with a single agent detected included 14 patients with enteroviral meningitis, 4 patients with Lyme borreliosis and 4 patients with tick-borne encephalitis; EM detected an undefined virus in the last patient. An unusual group of 8 patients with two agents detected comprised 5 patients with enteroviruses and spirochetes, 2 patients with tick-borne encephalitis and undefined viruses and 1 patient with a spirochete and an undetermined virus. CONCLUSION: EM can aid in explaining the etiology of aseptic neuroinfections. However, the clinical interpretation of results remains problematic, such as detection of unknown viruses or two possible agents in 8 out of 34 patients.

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.

Genetic detection of Dobrava/Belgrade virus in a Czech patient with Haemorrhagic fever with renal syndrome.

In the summer of 2008, a 15-year-old boy was hospitalized in a paediatric intensive care unit in the Czech Republic. Laboratory diagnosis of hantavirus infection was established by serological and molecular methods. Sequence and phylogenetic analyses showed that the causative strain was Dobrava/Belgrade virus, which is genetically closer to strains associated with Apodemus flavicollis rodents.

[Serological characteristics of hantaviruses from clinical specimens analyzed in 1998-2008 in the Department of Virology, Public Health Institute, Ostrava]. / Výsledky sérologie hantaviru z klinických vzorku vysetrených v obdobi 1998-2008 na oddeleni virologie Zdravotniho ustavu v Ostrav.

In 1998 - 2008, serum samples from 464 patients, predominantly residents of the Moravia-Silesian Region, were examined in the Department of Virology, Public Health Institute in Ostrava, using Enzyme-Linked ImmunoSorbent Assay (ELISA) for the detection of specific anti-hantavirus antibodies. Seropositivity was ascertained in 41 persons (8.8%). More patients tested seropositive against Hantaan virus (24, i.e. 58.5%) than against Puumala virus (13, i.e. 31.7%). Four persons were reactive against both antigens. Clinical symptoms corresponding to hantavirus infection were observed in 19 seropositive patients. Fifteen of them had antibodies reactive with Hantaan virus antigen (cross-reactive with anti-Dobrava virus), 3 patients had antibodies against Puumala virus and 1 patient had both types of antibodies. Clinical data on the other seropositive persons were lacking. The higher rate of Dobrava virus infections in the Moravian-Silesian Region seems to be associated, among others, with the geographic distribution of striped field mouse (Apodemus agrarius) which is the main reservoir of Dobrava virus in Central Europe.

Micromodification of virus-neutralisation assay with vital staining in 96-well plate and its use in diagnostics of Tahyna virus infections.

Virus neutralization test (VNT) is considered to be the gold standard for arbovirus serology because of its high specificity and sensitivity. Its micromodification in 96-well plate with vital staining of cell cultures was developed in the National Reference Laboratory (NRL) for Arboviruses of the Czech Republic and is used for the detection of specific antibodies against various viruses, mainly arboviruses. The test procedure is described for the Tahyna virus micromodified neutralization assay in 96-well plate. Results of an anti-Tahyna antibody survey conducted among the population of northern Moravia using the VNT assay are presented. The overall anti-Tahyna seroprevalence among 1001 tested persons was 3.80%. The highest positivity rate was found in persons aged over 59 years (17.53%) comparing to children with the seroprevalence rates of 0.00% and 0.56% in the age groups 0-5 years and 6-14 years, respectively.

[Experience with serological diagnosis of chikungunya fever]. / Zkusenosti se sérologickou diagnostikou horecky chikungunya.

BACKGROUND: During the year 2006 first imported cases of chikungunya fever in Europe occured contextual to the epidemic in the area of Indian ocean. In summer 2007 also autochthonnic chikungunya infections in the northern part of Italy appeared. On the basis of these facts serologic diagnostics of chikungunya fever was initiated in the National Reference Laboratory (NRL) for Arboviruses of the Czech Republic. MATERIAL AND METHODS: Complement-fixation assay was estabilished in 2006. Micromodification of virus-neutralisation assay in 96-well plate with staining of the cell cultures for detection of anti-chikungunya v. antibodies was developed and estabilished for improvement of the diagnostics in 2007. Consequently in 2008 the diagnostics was completed with indirect immunofluorescence assay for detection of anti-chikungunya v. IgG and IgM antibodies using the commercial EUROIMMUN assay. Principle of virus-neutralisation and the test procedure is described in the paper. Results reached by the use of all these methods are compared. RESULTS: From February 2006 to February 2008 110 serum samples from 104 persons were tested for anti-chikungunya v. antibodies. In 4 pateints acute chikungunya v. infection was proved and two other persons revealed seropositivity without acute infection. CONCLUSIONS: Qualitative correspondence between the particular methods was demonstrated and a benefit of virus-neutralisation assay for confirmation of the results was proved.

[The first case of imported infection of Chikungunya virus in the Czech Republic]. / První prukaz importované infekce virem Chikungunya v Ceské republice.

The authors describe the first confirmed case of tropical fever caused by Chikungunya virus imported into the Czech Republic. As the virus belonging to the Alphavirus genus of the Togaviridae family is transmitted by mosquitoes of the genus Aedes it is classified as an arbovirus. A 43-year-old woman became ill following her arrival from the island of Mauritius where she had stayed during an epidemic. The patient presenting with typical symptoms of the disease recovered completely. Chikungunya virus as the etiological agent was confirmed serologically by the complement fixation reaction in the Czech National Reference Laboratory for Arboviruses.