Meningoencephaloradiculitis following infection with tick borne encephalitis virus: case report and review of the literature

Tick borne encephalitis (TBE) is an infectious zoonotic disease caused by an RNA virus that is endemic to Central and Eastern Europe, Russia, and large parts of Asia. The tick borne encephalitis virus (TBEV) is transmitted through the saliva of infected ticks and infected goat milk. In the vast majority of cases, an infection with TBEV has a subclinical course. However, in some cases, it leads to neurological symptoms due to meningitis, meningoencephalitis, meningoencephalomyelitis, or meningoencephaloradiculitis. Here, we present the first case of meningoencephaloradiculitis in Belgium.

Seroprevalence of tick-borne-encephalitis virus in wild game in Mecklenburg-Western Pomerania (north-eastern Germany)

Mecklenburg-Western Pomerania, a federal state in the north east of Germany, has never been a risk area for TBEV infection, but a few autochthonous cases, along with TBEV-RNA detection in ticks, have shown a low level of activity in natural foci of the virus in the past. As wild game and domestic animals have been shown to be useful sentinels for TBEV we examined sera from wild game shot in Mecklenburg-Western Pomerania for the prevalence of TBEV antibodies. A total of 359 sera from wild game were investigated. All animals were shot in Mecklenburg-Western Pomerania in 2012. Thirteen of 359 sera tested positive or borderline for anti-TBEV-IgG with ELISA and four samples tested positive using NT. The four TBEV-positive sera confirmed by NT constitute the first detection of TBEV-antibodies in sera of wild game in Mecklenburg-Western Pomerania since 1986-1989. This underlines that the serological examination of wild game can be a useful tool in defining areas of possible TBEV infection, especially in areas of low TBEV-endemicity.

Surveillance of tick-borne encephalitis virus in wild birds and ticks in Tomsk city and its suburbs (Western Siberia)

To study the role of wild birds in the transmission of tick borne encephalitis virus (TBEV), we investigated randomly captured wild birds bearing ixodid ticks in a very highly endemic TBE region located in Tomsk city and its suburbs in the south of Western Siberia, Russia. The 779 wild birds representing 60 species were captured carrying a total of 841 ticks, Ixodes pavlovskyi Pom., 1946 (n=531), Ixodes persulcatus P. Sch., 1930 (n=244), and Ixodes plumbeus Leach. 1815 (n=66). The highest average number of ticks per bird in a particular species was found for the fieldfare (Turdus pilaris Linnaeus, 1758) (5.60 ticks/bird) and the tree pipit (Anthus trivialis Linnaeus, 1758) (13.25 ticks/bird). Samples from wild birds and ticks collected in highly endemic periods from 2006 to 2011 were tested for the TBEV markers using monoclonal modified enzyme immunoassay (EIA) and RT-PCR. TBEV RNA and antigen were found in 9.7% and 22.8% samples collected from wild birds, respectively. TBEV markers were also detected in 14.1% I. persulcatus ticks, 5.2% I. pavlovskyi, and 4.2% I. plumbeus ticks collected from wild birds. Two TBEV strains were also isolated on PKE (pig kidney embryo) cells from fieldfare and Blyth's reed warbler (Acrocephalus dumetorum Blyth, 1849). Sequencing of 5'-NCR of TBEV revealed that all TBEV isolates belong to Far Eastern (dominate) and Siberian genotypes. Several phylogenetic subgroups included TBEV sequences novel for the Tomsk region. Our data suggest that wild birds are potential disseminators of TBEV, TBEV-infected ixodid ticks, and possibly other tick-borne infections.

Detection of Quang Binh virus from mosquitoes in China

Flaviviruses present a wide range of genetic diversity and exhibit diverse host relationships. Mosquito-borne flaviviruses have recently been isolated and characterized worldwide. Yunnan Province of China is one of the richest areas of species diversity and is the center of multi-species evolution in mainland Asia, which supports the circulation of numerous arthropod-borne viruses (arboviruses). In a screening program of arboviruses, mosquitoes were collected during the mosquito activity season in the Yunnan Province from 2007 to 2010. Eleven flavivirus strains, named Yunnan Culex flaviviruses (YNCxFVs), were obtained from Culex tritaeniorhynchus and Anopheles sinensis specimens. Sequence analyses based on partial nonstructural protein (NS) 5 gene indicated that the YNCxFVs shared 92.8-99.6% nucleotide identity with each other and were similar to the Culex-related flaviviruses. The complete genome of one representative isolate, LSFlaviV-A20-09, was sequenced. The genome was 10,865 nucleotides long and contained a single, long open reading frame (ORF) of 10,080 nucleotides that encoded a 3360-aa polyprotein. This genome was most closely related to the Quang Binh virus (QBV) VN180 strain, an insect-specific flavivirus isolated from Culex mosquitoes in Vietnam, but only had 83.0% nucleotide and 93.8% amino acid identities for the ORF sequence. The genome has approximately 66.3%-68.5% nucleotide sequence and 69.3-73.3% amino acid sequence identities to other Culex flaviviruses, and only has 47.9-57.9% nucleotide sequence and 38.7-55.1% amino acid sequence identities to Coquillettidia-related, Mansonia-related and Aedes-related flaviviruses. Phylogenetic analyses revealed that the LSFlaviV-A20-09 fell into the Culex-related flavivirus clade. Our discoveries provide more information regarding the heterogeneity of viruses that infect mosquitoes.