Elpida Papadopoulou

Detection of West Nile Virus Lineage 2 in Culex Mosquitoes, Greece, 2012

To gain insight into the strain(s) causing human cases of West Nile virus (WNV) infection in Greece in 2012, mosquitoes were collected and tested for probable WNV infection. WNV lineage 2 sequences were obtained from two of 14 Culex spp. pools collected in Xanthi Prefecture, and especially in the municipality with the highest incidence in Greece. As in the 2 previous years, the strain contains the H249P substitution in the NS3 protein. It seems that this specific strain is fully established in Greece and causes large-scale outbreaks. Thus, prevention and control measures have to be taken, while enhanced surveillance is needed.

Detection of West Nile virus and insect-specific flavivirus RNA in Culex mosquitoes, central Macedonia, Greece.

BACKGROUND West Nile virus (WNV) emerged in central Macedonia, northern Greece, in 2010. The aim of the study was to test Culex mosquitoes for genetic detection of WNV and other flaviviruses, and to check whether the detection of WNV in mosquitoes was correlated with the occurrence of human WNV cases. METHODS During 2013, 25 780 Culex spp. mosquitoes were collected from central Macedonia, grouped into 295 pools, according to collection site and date, and tested for the presence of flavivirus RNA. RESULTS Thirteen (4.4%) pools were flavivirus-positive. WNV lineage 2 was detected in nine (3.1%) pools, and insect-specific flaviviruses (ISFV) in four (1.4%). Three ISFV nucleotide sequences were 98% identical to Culex theileri flavivirus, previously detected in the Iberian peninsula, while the fourth sequence differed by >25% from all known flaviviruses. In most units of central Macedonia WNV detection in mosquitoes preceded the occurrence of human cases by approximately one month. CONCLUSIONS Detection of WNV lineage 2 in mosquitoes for a fourth consecutive year suggests that the virus is established in Greece. Entomological surveillance provides an early warning system for the circulation of the virus. The detection of Culex theileri flavivirus extends the known range of this virus.

Molecular epidemiology of Crimean–Congo hemorrhagic fever in Bulgaria—An update

Crimean–Congo hemorrhagic fever (CCHF) is endemic in Bulgaria. During 2013–2014, 11 confirmed CCHF cases have been reported in the country (seven in 2013 and four in 2014). The present study provides the CCHF molecular epidemiology in Bulgaria based on all currently available S, M, and L RNA segment nucleotide sequences spanning the years 1978–2014. A relatively low genetic difference (0–6%, the maximum seen in the M RNA segment) was seen among the CCHFV sequences suggesting that a slow evolving CCHFV strain belonging to “Europe 1” clade is present in Bulgaria. Although the virus emerged in new foci during the recent years, it is more active in the established endemic foci which seem to offer the most suitable ecosystem and environment. Understanding the CCHF epidemiology and virus evolution is the basis for public health programs and vaccine design. J. Med. Virol. 88:769–773, 2016.

Molecular detection and isolation of West Nile virus from a human case in northern Greece, 2013

In order to laboratory confirm the first suspected West Nile fever case in 2013 in northern Greece, a combination of serological molecular and culture methods were applied. It was shown that the causative West Nile virus strain belonged to lineage 2, and possessed the amino acid substitution H249P in the NS3 protein, as in previous years. The significance of this specific strain in Europe remains to be elucidated.

Challenges in laboratory diagnosis of acute viral central nervous system infections in the era of emerging infectious diseases: the syndromic approach.

ABSTRACT Introduction: Many acute viral infections of the central nervous system (CNS) remain without etiological diagnosis. Specific treatment is available for only few of them; however, accurate diagnosis is essential for patient’s life and public health. Areas covered: In the current article, the main parameters playing a role for a successful etiological diagnosis of acute CNS infections are analysed and the syndromic approach based on clinical and demographic data combined with surrogated indicators is discussed. For the development of a relevant test panel, knowledge on the microbes causing CNS infections in a particular geographic region is essential. The modern screening strategies covering a large panel of potential causative agents are described. Examples of the successful application of next generation sequencing in the identification of etiological agents, including novel and emerging viruses, are given. Expert commentary: Knowledge on epidemiology of the viruses, expertise on syndromic grouping of the etiological agents and advances in technology enable the laboratory diagnosis of acute CNS infections, and the rapid identification, containment and mitigation of probable outbreaks.

Acute viral infections of the central nervous system, 2014-2016, Greece

In order to investigate the viral etiology of acute infections of central nervous system (CNS), multiplex and single PCRs combined with serology for arboviruses were applied on samples from 132 hospitalized patients in Greece during May 2014‐December 2016. A viral pathogen was detected in 52 of 132 (39.4%) cases with acute CNS infection. Enteroviruses predominated (15/52, 28.8%), followed by West Nile virus (9/52, 17.3%). Phleboviruses, varicella‐zoster virus, and Epstein‐Barr virus accounted for 15.4%, 13.5%, and 11.5% of the cases, respectively. The study gives an insight into the etiology of viral CNS infections in a Mediterranean country, where arboviruses should be included in the differential diagnosis of acute CNS infections.

Zika virus infection in a newly married Greek couple

Zika virus (ZIKV) is a member of the Flaviviridae family causing asymptomatic or mildly symptomatic infections with fever, rash, arthralgia and headache. It is transmitted by the Aedes species mosquitoes and also sexually and transplacentally, and has been recently associated with congenital neurologic birth defects in South and Central America. We report the case of a newly married couple from Greece who travelled to Cuba for their honeymoon and developed mild symptoms consistent with arboviral infection. After returning to Greece, they were found to have been infected by Zika virus during their honeymoon. These are the first two cases of Zika virus infection in Greece, the southeastern border of Europe, denoting that Zika virus infection poses a threat for public health worldwide, since returning travelers could be asymptomatic carriers of the virus, not only leading to risk of neurologic birth defects for their offspring but also the real risk of transmission of the virus in their country by local Aedes mosquitoes.

Imported Chikungunya fever case in Greece in June 2014 and public health response.

We report about the first imported case of Chikungunya fever in Greece in a Greek traveler returning from the Dominican Republic and the associated public health response. We investigated the case and performed focused epidemiological and entomological investigation in all areas the patient visited during the infectious period, to identify the targeted interventions needed. Entomological investigation revealed the occurrence of the competent vector Aedes albopictus (Diptera: Culicidae) in the environment surrounding the hospital where the patient was admitted and in her workplace. All captured mosquitoes tested negative for Chikungunya virus. We further conducted clinical and laboratory examination of the patient’s co-travelers, gave advice on appropriate personal preventive measures against mosquito bites to the patient and co-travelers and on vector control, and raised awareness among health professionals throughout Greece. The risk of introduction and local transmission of Chikungunya and other arboviruses in Greece and other European countries is present, as the competent vector exists in many parts of Europe. Public health professionals, travel medicine specialists and clinicians should maintain awareness regarding this possibility of importation of arbovirus cases in order to provide the appropriate advice, seek the prompt diagnosis, and implement appropriate interventions. Mobilization of various stakeholders will lead to enhanced epidemiological and entomological surveillance that will allow for improved risk assessment in each area.

Uukuniemi virus, Czech Republic

Following the identification of severe fever with thrombocytopenia syndrome and Heartland viruses, the interest on tick-borne phleboviruses has increased rapidly. Uukuniemi virus has been proposed as a model for tick-borne phleboviruses. However, the number of available sequences is limited. In the current study we performed whole-genome sequencing on two Uukuniemi viral strains isolated in 2000 and 2004 from Ixodes ricinus ticks in the Czech Republic. Both strains cluster together with Potepli63 strain isolated in the country in 1963. Although the Czech strains were isolated many years apart, a high identity was seen at the nucleotide and amino acid levels, suggesting that UUKV has a relatively stable genome.

Isolation and whole-genome sequencing of a Crimean-Congo hemorrhagic fever virus strain, Greece

Crimean-Congo hemorrhagic fever virus (CCHFV) was isolated from a pool of two adult Rhipicephalus bursa ticks removed from a goat in 2015 in Greece. The strain clusters into lineage Europe 2 representing the second available whole-genome sequenced isolate of this lineage. CCHFV IgG antibodies were detected in 8 of 19 goats of the farm. Currently CCHFV is not associated with disease in mammals other than humans. Studies in animal models are needed to investigate the pathogenicity level of lineage Europe 2 and compare it with that of other lineages.