Letter to the editor: Pending challenges in passenger contact tracing in air transport – a German perspective

Peer Reviewe

Evaluation of serological diagnostic test systems assessing the immune response to Japanese encephalitis vaccination.

A new commercial anti-Japanese encephalitis virus IgM and IgG indirect immunofluorescence test (IIFT) was evaluated for the detection of the humoral immune response after Japanese encephalitis vaccination. The IgM IIFT was compared to two IgM capture ELISAs and the IgG IIFT was analysed in comparison to a plaque reduction neutralization test (PRNT50) and an IgG ELISA. Moreover, the course of the immune reaction after vaccination with an inactivated JEV vaccine was examined. For the present study 300 serum samples from different blood withdrawals from 100 persons vaccinated against Japanese encephalitis were used. For the IgM evaluation, altogether 78 PRNT50 positive samples taken 7 to 56 days after vaccination and 78 PRNT50 negative sera were analyzed with the Euroimmun anti-JEV IgM IIFT, the Panbio Japanese Encephalitis – Dengue IgM Combo ELISA and the InBios JE Detect IgM capture ELISA. For the IgG evaluation, 100 sera taken 56 days after vaccination and 100 corresponding sera taken before vaccination were tested in the PRNT50, the Euroimmun anti-JEV IgG IIFT, and the InBios JE Detect IgG ELISA. The Euroimmun IgM IIFT showed in comparison to the Panbio ELISA a specificity of 95% and a sensitivity of 86%. With respect to the InBios ELISA, the values were 100% and 83.9%, respectively. The analysis of the Euroimmun IgG IIFT performance and the PRNT50 results demonstrated a specificity of 100% and a sensitivity of 93.8%, whereas it was not possible to detect more than 6.6% of the PRNT50 positive sera as positive with the InBios JE Detect IgG ELISA. Thus, the IIFT is a valuable alternative to the established methods in detecting anti-JEV antibodies after vaccination in travellers and it might prove useful for the diagnosis of acutely infected persons

Co-circulation of West Nile virus and distinct insect-specific flaviviruses in Turkey

Background: Active vector surveillance provides an efficient tool for monitoring the presence or spread of emerging or re-emerging vector-borne viruses. This study was undertaken to investigate the circulation of flaviviruses. Mosquitoes were collected from 58 locations in 10 provinces across the Aegean, Thrace and Mediterranean Anatolian regions of Turkey in 2014 and 2015. Following morphological identification, mosquitoes were pooled and screened by nested and real-time PCR assays. Detected viruses were further characterised by sequencing. Positive pools were inoculated onto cell lines for virus isolation. Next generation sequencing was employed for genomic characterisation of the isolates. Results: A total of 12,711 mosquito specimens representing 15 species were screened in 594 pools. Eleven pools (2%) were reactive in the virus screening assays. Sequencing revealed West Nile virus (WNV) in one Culex pipiens (s. l.) pool from Thrace. WNV sequence corresponded to lineage one clade 1a but clustered distinctly from the Turkish prototype isolate. In 10 pools, insect-specific flaviviruses were characterised as Culex theileri flavivirus in 5 pools of Culex theileri and one pool of Cx. pipiens (s. l.), Ochlerotatus caspius flavivirus in two pools of Aedes (Ochlerotatus) caspius, Flavivirus AV-2011 in one pool of Culiseta annulata, and an undetermined flavivirus in one pool of Uranotaenia unguiculata from the Aegean and Thrace regions. DNA forms or integration of the detected insect-specific flaviviruses were not observed. A virus strain, tentatively named as Ochlerotatus caspius flavivirus Turkey, was isolated from an Ae. caspius pool in C6/36 cells. The viral genome comprised 10,370 nucleotides with a putative polyprotein of 3,385 amino acids that follows the canonical flavivirus polyprotein organisation. Sequence comparisons and phylogenetic analyses revealed the close relationship of this strain with Ochlerotatus caspius flavivirus from Portugal and Hanko virus from Finland. Several conserved structural and amino acid motifs were identified. Conclusions: We identified WNV and several distinct insect-specific flaviviruses during an extensive biosurveillance study of mosquitoes in various regions of Turkey in 2014 and 2015. Ongoing circulation of WNV is revealed, with an unprecedented genetic diversity. A probable replicating form of an insect flavivirus identified only in DNA form was detected.U.S. Armed Forces Health Surveillance Board Global Emerging Infections Surveillance and Response System (AFHSB-GEIS) research; Walter Reed Army Institute of Research; Smithsonian InstitutionSmithsonian Institution; Georg Forster Research Fellowship (HERMES); Alexander von Humboldt Foundation, GermanyAlexander von Humboldt FoundationA U.S. Armed Forces Health Surveillance Board Global Emerging Infections Surveillance and Response System (AFHSB-GEIS) research award (to YML) supported this study. This research was performed in part under a Memorandum of Understanding between the Walter Reed Army Institute of Research and the Smithsonian Institution, with institutional support provided by both organisations. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The material to be published reflects the views of the authors and should not be construed to represent those of the United States Department of the Army or the United States Department of Defense. KE was a 2015 recipient of the Georg Forster Research Fellowship (HERMES) for Experienced Researchers, of the Alexander von Humboldt Foundation, Germany

Isolation and genomic characterization of Culex theileri flaviviruses in field-collected mosquitoes from Turkey

Vector surveillance for the arthropod-borne infections has resulted in the isolation of a growing number of novel viruses, including several flavivirus strains that exclusively replicate in insects. This report describes the isolation and genomic characterization of four insect-specific flaviviruses frommosquitoes, previously collected from various locations in Turkey. C6/36 Aedes albopictus and Vero cell lines were inoculated with mosquito pools. On C6/36 cells, mild cytopathic effects, characterized as rounding and detachment, were observed in four pools that comprised female Culex theileri mosquitoes. Complete (3 isolates, 10,697 nucleotides) or near-complete (1 isolate, 10,452 nucleotides) genomic characterization was performed in these culture supernatants via next generation sequencing. All strains demonstrated high genetic similarities, with over 99% identity match on nucleotide and amino acid alignments, revealing them to be different isolates of the same virus. Sequence comparisons identified the closest relative to be the Culex theileri flavivirus (CTFV) strains, originally characterized in Portugal. Phylogenetic analyses demonstrated that the isolates remained distinct as a cluster but formed amonophyletic group with CTFV strains, and shared a common ancestor with Quang Binh or related Culex flaviviruses. The organization of the viral genome was consistent with the universal flavivirus structure and stem-loops; conserved motifs and imperfect tandem repeats were identified in the non-coding ends of the viral genomes. A potential ribosomal shifting site, resulting in the translation of an additional reading frame, was detected. The deduced viral polyprotein comprised 3357 amino acids and was highly-conserved. Amino acid variations, presumably associated with adaptive environmental pressures, were identified. These isolates comprise the first fully characterized insect-specific flaviviruses in Turkey. Their impact on West Nile virus circulation, which is also endemic in the study region, remains to be explored. (C) 2016 Elsevier B.V. All rights reserved.Armed Forces Health Surveillance Center, Global Emerging Infections Surveillance and Response System (AFHSC-GEIS), United States [W81XWH-11-2-0174]; Georg Forster Research Fellowship (HERMES) for Experienced Researchers by Alexander von Humboldt Foundation; National Research Council (NRC) Research Associateship Award at the Walter Reed Army Institute of ResearchThis study was partially supported by The Armed Forces Health Surveillance Center, Global Emerging Infections Surveillance and Response System (AFHSC-GEIS), United States (W81XWH-11-2-0174) (with Yvonne-Marie Linton as the principal investigator). KE is a recipient of the Georg Forster Research Fellowship (HERMES) for Experienced Researchers by the Alexander von Humboldt Foundation, 2015. This manuscript was prepared whilst YML held a National Research Council (NRC) Research Associateship Award at the Walter Reed Army Institute of Research. This research was performed in part under a Memorandum of Understanding between the Walter Reed Army Institute of Research and the Smithsonian Institution, with institutional support provided by both organizations. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The material to be published reflects the views of the authors and should not be construed to represent those of the US Department of the Army or the US Department of Defense

Co-circulation of West Nile virus and distinct insect-specific flaviviruses in Turkey

Background: Active vector surveillance provides an efficient tool for monitoring the presence or spread of emerging or re-emerging vector-borne viruses. This study was undertaken to investigate the circulation of flaviviruses. Mosquitoes were collected from 58 locations in 10 provinces across the Aegean, Thrace and Mediterranean Anatolian regions of Turkey in 2014 and 2015. Following morphological identification, mosquitoes were pooled and screened by nested and real-time PCR assays. Detected viruses were further characterised by sequencing. Positive pools were inoculated onto cell lines for virus isolation. Next generation sequencing was employed for genomic characterisation of the isolates. Results: A total of 12,711 mosquito specimens representing 15 species were screened in 594 pools. Eleven pools (2%) were reactive in the virus screening assays. Sequencing revealed West Nile virus (WNV) in one Culex pipiens (s.l.) pool from Thrace. WNV sequence corresponded to lineage one clade 1a but clustered distinctly from the Turkish prototype isolate. In 10 pools, insect-specific flaviviruses were characterised as Culex theileri flavivirus in 5 pools of Culex theileri and one pool of Cx. pipiens (s.l.), Ochlerotatus caspius flavivirus in two pools of Aedes (Ochlerotatus) caspius, Flavivirus AV-2011 in one pool of Culiseta annulata, and an undetermined flavivirus in one pool of Uranotaenia unguiculata from the Aegean and Thrace regions. DNA forms or integration of the detected insect-specific flaviviruses were not observed. A virus strain, tentatively named as “Ochlerotatus caspius flavivirus Turkey”, was isolated from an Ae. caspius pool in C6/36 cells. The viral genome comprised 10,370 nucleotides with a putative polyprotein of 3,385 amino acids that follows the canonical flavivirus polyprotein organisation. Sequence comparisons and phylogenetic analyses revealed the close relationship of this strain with Ochlerotatus caspius flavivirus from Portugal and Hanko virus from Finland. Several conserved structural and amino acid motifs were identified. Conclusions: We identified WNV and several distinct insect-specific flaviviruses during an extensive biosurveillance study of mosquitoes in various regions of Turkey in 2014 and 2015. Ongoing circulation of WNV is revealed, with an unprecedented genetic diversity. A probable replicating form of an insect flavivirus identified only in DNA form was detected

Establishment and evaluation of serological assays for the detection of highly pathogenic arboviruses

Für viele tropische Infektionserreger herrscht ein Mangel an guten, kommerziell hergestellten, serologischen Testen. Meist beruht die serologische Diagnostik für arbovirale Erreger auf in-house Testen und ist nur in wenigen Laboren verfügbar. Eine schnelle Diagnostik ist jedoch unerlässlich, um z.B. eine eingeschleppte, tropische Krankheit erkennen und im Notfall die nötigen Gegenmaßnahmen treffen zu können. Um einer größeren Zahl von Laboratorien qualitätsgesicherte, serologische Nachweissysteme zur Verfügung zu stellen, wurden im Rahmen der Promotionsarbeit umfangreiche Testevaluierungen für die fünf folgenden, mit Virus-Vollantigen hergestellten Immunfluoreszenzteste (IIFTs) durchgeführt und die Ergebnisse ausgewertet: anti-Chikungunya-Virus (CHIKV), anti-Japanisches Encephalitis-Virus (JEV), anti-Dengue-Virus (DENV), anti-Sandfliegen-Fieber-Viren (SFV) und anti-Rifttalfieber-Virus (RVFV) IIFT. Zudem wurden zwei rekombinante Testsysteme, für das Krim-Kongo Hämorrhagisches Fieber-Virus (CCHFV) und das DENV entwickelt und beide Teste ebenfalls in einer Studie mit charakterisierten Serumpanels evaluiert. Der anti-CHIKV IIFT wurde im Vergleich zu zwei in-house Testen evaluiert. Er zeigte für IgM eine Sensitivität von 96,9 %, sowie eine Spezifität von 98,3 %. Für den IgG-IIFT wurde eine Sensitivität von 95,4 % und eine Spezifität von 100 % berechnet. Die Evaluierung des anti-JEV IIFTs wurde im Vergleich zu zwei kommerziellen ELISAs und einem Plaque-Reduktions-Neutralisationstest (PRNT) durchgeführt. Der IgM-IIFT zeigte im Vergleich zum Panbio IgM-ELISA eine Sensitivität von 86 % und eine Spezifität von 95 %. Im Vergleich zum InBios IgM-ELISA wurde für den IgM-IIFT eine Sensitivität von 83,9 % und eine Spezifität von 100 % ermittelt. Der IgG-IIFTs zeigte im Vergleich zum PRNT eine Sensitivität von 93,8 % und eine Spezifität von 100 %. Der anti-DENV IIFT wurde hinsichtlich der Fähigkeit untersucht, den per PCR bestimmten Serotyp der Infektion serologisch zu identifizieren. Mittels des IgM-IIFTs, konnten 52 % der IgM- reaktiven Seren mit dem anti-DENV IIFT richtig serotypisiert werden. Bei weiteren 48 % der Seren zeigten mehrere Serotypen eine gleich starke Fluoreszenz. Bei 92 % dieser Seren war jedoch der per PCR bestimmte, unter den am stärksten reaktiven Serotypen. Der anti-SFV-IIFT wurde mit zwei kommerziell erhältlichen Testen, einem anti-Toscana-Virus (TOSV) ELISA und einem anti-TOSV Blot, verglichen. Die stärkste Reaktivität im ELISA und Blot konnte in den 25 Seren gefunden werden, die im IIFT sowohl mit dem SFV Naples- als auch mit dem TOSV-Substrat reagiert hatten. Während im ELISA 28 % der Seren als positiv detektiert wurden, waren 98 % der Seren im Blot positiv. In den 46 Seren, die im IIFT ausschließlich mit dem TOSV-Substrat reagiert hatten, wurden mit dem ELISA 10,9 % als grenzwertig und mit dem Blot 30 % als positiv identifiziert. Der IIFT zeigte insgesamt eine höhere Sensitivität als der Blot, und eine viel höhere Sensitivität als der ELISA. Der anti-RVFV IIFT wurde im Vergleich zu einem in-house ELISA evaluiert. Die Spezifität des IgM-IIFTs lag bei 99,4 %, die Sensitivität konnte aufgrund der zu geringen Probenanzahl nicht ermittelt werden. Der IgG-IIFT zeigte eine Sensitivität von 93,3 % und eine Spezifität von 99,5 %. Es wurde ein rekombinanter anti-CCHFV IIFT entwickelt. Dafür wurde zunächst die Transfektion und Expression des Nukleoproteins und der Glykoproteine in HEK 293RKI-Zellen optimiert. Der anti-CCHFV IIFT wurde im Anschluss mit vier verschiedenen Serumpanels, die in verschiedenen in-house ELISAs als anti-CCHFV-positiv vorcharakterisiert worden waren, und einem Panel von Blutspenderseren analysiert. Die Ergebnisse dieser Serumpanels, v.a. für den IgM-IIFT, unterschieden sich stark. Die Sensitivitäten für den IgM-IIFT lagen bei 54,3 %, 44,4 %, 93,3 %, sowie 92,9 % und die Spezifität bei 97,8 %. Für den IgG-IIFT lagen die Sensitivitäten bei 83,3 %, 100 %, 100 % und 69,2 % und die Spezifität bei 100 %. Für den rekombinanten anti-DENV Test wurden die vier NS1-Proteine ebenfalls jeweils in HEK 293RKI-Zellen exprimiert. Eine korrekte Serotypisierung war mit dem IgG-IIFT im Panel 1 bei 54,5 % der IgG- reaktiven Seren und im Panel 2, das hauptsächlich aus Seren nach Sekundärinfektion bestand, bei 28,6 % der IgG-reaktiven Seren möglich. Werden im Panel 1 nur die Seren mit den reaktiven DENV-Serotypen 1, 2 und 4 betrachtet, so konnten 75 % im IgG-IIFT richtig serotypisiert werden. Insgesamt zeigten die verschiedenen IIFTs im Vergleich zu den verwendeten in- house bzw. kommerziellen Testen, vergleichbare Ergebnisse und können in den Laboratorien als evaluierte Alternativen zur Diagnose von tropischen, arboviralen Erkrankungen eingesetzt werden. Der IIFT stellt eine schnelle und effiziente Testplattform dar, mit der man vor allem Einzelseren, für die eine Untersuchung im ELISA zu aufwendig ist, analysieren kann. Die Entwicklung rekombinanter IIFTs bietet zudem eine interessante Möglichkeit serologische Teste für Erreger der biologischen Sicherheitsstufe 4 (BSL-4) ohne größere Hindernisse herzustellen, und so auch für höher pathogene Erreger kommerzielle, serologische Diagnostika vielen Laboren zugänglich zu machen. Weiterhin lassen sich durch die Auswahl wenig kreuzreaktiver Proteine bzw. spezifischer Proteinbereiche in rekombinanten Testsystemen störende Kreuzreaktivitäten reduzieren. Insgesamt stellen rekombinant hergestellte Virusantigen-Substrate eine vielversprechende Alternative für die Herstellung von IIFT-BIOCHIPs dar.There is a lack of good and commercially available serological assays for many tropical infectious agents. The serological diagnosis of arboviruses relies mainly on in-house assays and is available only in few laboratories. Yet, a rapid diagnosis is crucial to identify a newly introduced tropical infection and to take the adequate counter measures. In order to provide an increased number of laboratories with quality assured, serological assays, extensive evaluations were performed for the following five indirect immunofluorescence tests (IIFTs) which are all produced with complete virus: anti-Chikungunya virus (CHIKV), anti-Japanese encephalitis virus (JEV), anti-Dengue virus (DENV), anti-Sandfly fever-virus (SFV) und anti-Rift valley fever virus (RVFV) IIFT. Additionally two recombinant test systems for the Crimean Congo hemorrhagic fever virus (CCHFV) and DENV were developed and both assays were likewise evaluated with characterised serum panels. The anti-CHIKV IIFT was evaluated in comparison to two in-house assays. It revealed for IgM a sensitivity of 96.9 % and 98.3 %. For the IgG IIFT the sensitivity was 95.4 % and the specificity 100 %. The evaluation of the anti-JEV IIFT was performed with two commercial ELISAs and a plaque reduction neutralization assay (PRNT). Compared to the Panbio IgM ELISA, the IgM IIFT showed a sensitivity of 86 % and a specificity of 95 %. In comparison to the InBios IgM ELISA the sensitivity was 83.9 % and the specificity 100 %. The IgG IIFT was evaluated against the PRNT and demonstrated a sensitivity of 93.8 % and a specificity of 100 %. The anti-DENV IIFT was analysed in respect to its capability to identify serologically the correct DENV serotype that was determined by PCR beforehand. Using the IgM IIFT, 52 % of the sera containing IgM antibodies were correctly serotyped by the anti-DENV IIFT. In further 48 % of the sera an equal fluorescence was detected, and in 92 % of these sera, the serotype determined by PCR was one of the most reactive serotypes. The anti-SFV IIFT was compared to two commercial assays, an anti-Toscana Virus (TOSV) ELISA and an anti-TOSV blot. The highest reactivity was found in the 25 sera, which reacted in the IIFT with the SFV Naples- and with the TOSV substrate. While 28 % of the sera were detected as positive by ELISA, 98 % were positive on the blot. Of the 46 sera, reactive only with the TOSV IIFT substrate, 10.9 % were equivocal in ELISA and 30 % positive with the blot. Altogether, the IIFT showed a higher sensitivity compared to the blot and a much higher sensitivity than the ELISA. The anti-RVFV IIFT was evaluated in comparison to an in-house ELISA. The specificity of the IgM IIFT was 99.4 %, while it was not possible to determine a sensitivity value, due to an insufficient number of samples. The IgG IIFT showed a sensitivity of 93.3 % and a specificity of 99.5 %. A recombinant anti-CCHFV IIFT was developed. For this, the transfection and expression of the nucleo- and the glycoproteins was optimised in HEK 293RKI cells. Subsequently, the anti-CCHFV IIFT was evaluated with four different sera panels, characterised as anti-CCHFV positive with different in-house ELISAs. The results varied strongly, especially for IgM. The sensitivities for the IgM IIFT were 54.3 %, 44.4 %, 93.3 % and 92.9 %, while the specificity was 97.8 %. For the IgG IIFT the sensitivities were 83.3 %, 100 %, 100 % and 69.2 %, the specificity was 100 %. For the recombinant anti-DENV assay the four NS1 proteins were likewise expressed in HEK 293RKI cells. In Panel 1 it was possible with the IgG IIFT to correctly serotype 54.5 % of the sera reactive with IgG. In Panel 2, which consisted mainly of sera with secondary DENV infections 28.6 % of the IgG-reactive sera were serotyped correctly. Considering only the reactive DENV serotypes 1, 2 and 4, it was possible to serotype 75 % of the sera correctly. Altogether, the different EUROIMMUN IIFTs showed comparable results to in-house and commercial assays and can be used as an extensively evaluated alternative for the diagnosis of tropical, arboviral diseases. The IIFT represents a rapid and efficient platform, especially for the diagnosis of single sera for which the analysis in ELISA is too laborious and cumbersome. The development of recombinant IIFTs provides the opportunity to produce commercial serological assays for biosafety level 4 (BSL-4) agents without need of a high risk containment facility. Thereby, these products for the diagnosis of highly pathogenic viruses become available for many laboratories. Furthermore, it is possible to select less cross reactive proteins or specific regions of proteins for the production of recombinant assays. The reduced cross reactivity allows to distinctively diagnose even highly related viruses. Altogether, recombinantly produced viral antigens represent a promising alternative for the production of IIFT-BIOCHIPs

Confirmed Exposure to Tick-Borne Encephalitis Virus and Probable Human Cases of Tick-Borne Encephalitis in Central/Northern Anatolia, Turkey

Tick-borne encephalitis virus (TBEV) is the aetiological agent of tick-borne encephalitis (TBE), a potentially fatal central nervous system infection of humans. TBE is endemic in many areas of Europe and Asia; however, very scarce data on TBEV activity are available from Turkey. We aimed to identify TBEV exposure in healthy blood donors and the impact of TBEV in central nervous system infections in Central/Northern Anatolia. Two-thousand four hundred and fifty four sera, collected from blood donors at Ankara, Konya, Eskişehir and Zonguldak branches of the Turkish Red Crescent Middle Anatolia Regional Blood Center, were analysed for TBEV serosurveillance. Paired serum and cerebrospinal fluid samples from 108 patients with the diagnosis of aseptic meningitis/encephalitis of unknown aetiology were also evaluated to identify TBE and neuroborreliosis cases. Commercial enzyme-linked immunosorbent assays and indirect immunofluorescence tests were employed for antibody detection. Forty-seven donor samples (1.9%) were reactive for TBEV IgG. In 25 persons with IgG reactivity (53.1%), risk factors for tick-borne infections were revealed. One sample from Zonguldak province (1/198; 0.5%) in the Black Sea region of Turkey was confirmed to possess neutralizing antibodies via plaque reduction neutralization test. TBEV IgM was detected in 9.2% (8/108) of the patients. IgM was accompanied by IgG reactivity in two persons where, in one, recent history of a tick bite was also identified. Intrathecal antibody production for TBEV could not be demonstrated. No evidence for Borrelia infections could be found. Confirmed exposure to TBEV and/or an antigenically similar tick-borne flavivirus is documented for the first time in blood donors in Zonguldak in Northern Anatolia. Probable cases of TBE have also been identified from Central Anatolia. The epidemiology of TBEV activity in Turkey needs to be assessed and benefits of vaccination for general population, risk groups or travellers must be considered

Characterization of a Culex theileri flavivirus variant in field-collected mosquitoes from Turkey

[No Abstract Available

A novel rhabdovirus, related to Merida virus, in field-collected mosquitoes from Anatolia and Thrace

Next-generation sequencing technologies have significantly facilitated the discovery of novel viruses, and metagenomic surveillance of arthropods has enabled exploration of the diversity of novel or known viral agents. We have identified a novel rhabdovirus that is genetically related to the recently described Merida virus via next-generation sequencing in a mosquito pool from Thrace. The complete viral genome contains 11,798 nucleotides with 83% genome-wide nucleotide sequence similarity to Merida virus. Five major putative open reading frames that follow the canonical rhabdovirus genome organization were identified. A total of 1380 mosquitoes comprising 13 species, collected from Thrace and the Mediterranean and Aegean regions of Anatolia were screened for the novel virus using primers based on the N and L genes of the prototype genome. Eight positive pools (6.2%) exclusively comprised Culex pipiens sensu lato specimens originating from all study regions. Infections were observed in pools with female as well as male or mixed-sex individuals. The overall and Cx. pipiens-specific minimal infection rates were calculated to be 5.7 and 14.8, respectively. Sequencing of the PCR products revealed marked diversity within a portion of the N gene, with up to 4% divergence and distinct amino acid substitutions that were unrelated to the collection site. Phylogenetic analysis of the complete and partial viral polymerase (L gene) amino acid sequences placed the novel virus and Merida virus in a distinct group, indicating that these strains are closely related. The strain is tentatively named Merida-like virus Turkey. Studies are underway to isolate and further explore the host range and distribution of this new strain.Armed Forces Health Surveillance Center, Global Emerging Infections Surveillance and Response System (AFHSC-GEIS), United States [W911QY-16-C-0160-P00001]This study was partially supported by the Armed Forces Health Surveillance Center, Global Emerging Infections Surveillance and Response System (AFHSC-GEIS), United States (with Yvonne Marie-Linton as the principal investigator) (grant agreement number: W911QY-16-C-0160-P00001)

Immunogenicity and safety of yellow fever vaccination for 102 HIV-infected patients

BACKGROUND: Yellow fever vaccine (17DV) has been investigated incompletely in human immunodeficiency virus (HIV)-infected patients, and adequate immunogenicity and safety are of concern in this population. METHODS: In the Swiss HIV Cohort Study, we identified 102 patients who received 17DV while they were HIV infected. We analyzed neutralization titers (NTs) after 17DV administration using the plaque reduction neutralization test. NTs of 1:>or=10 were defined as reactive, and those of 1:<10 were defined as nonreactive, which was considered to be nonprotective. The results were compared with data for HIV-uninfected individuals. Serious adverse events were defined as hospitalization or death within 6 weeks after receipt of 17DV. RESULTS: At the time of 17DV administration, the median CD4 cell count was 537 cells/mm(3) (range, 11-1730 cells/mm(3)), and the HIV RNA level was undetectable in 41 of 102 HIV-infected patients. During the first year after vaccination, fewer HIV-infected patients (65 [83%] of 78; P = .01) than HIV-uninfected patients revealed reactive NTs, and their NTs were significantly lower (P < .001) than in HIV-uninfected individuals. Eleven patients with initially reactive NTs lost these reactive NTs <or= 5 years after vaccination. Higher NTs during the first year after vaccination were associated with undetectable HIV RNA levels, increasing CD4 cell count, and female sex. We found no serious adverse events after 17DV administration among HIV-infected patients. CONCLUSION: Compared with HIV-uninfected individuals, HIV-infected patients respond to 17DV with lower reactive NTs, more often demonstrate nonprotective NTs, and may experience a more rapid decline in NTs during follow-up. Vaccination with 17DV appears to be safe in HIV-infected individuals who have high CD4 cell counts, although rate of serious adverse events of up to 3% cannot be excluded