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. 2020 Sep 24;9(10):780.
doi: 10.3390/pathogens9100780.

Transstadial Transmission and Replication Kinetics of West Nile Virus Lineage 1 in Laboratory Reared Ixodes ricinus Ticks

Cristian Răileanu  1 , Oliver Tauchmann  1 , Ana Vasić  1   2 , Ulrike Neumann  1 , Birke Andrea Tews  1 , Cornelia Silaghi  1   3
Affiliations

Transstadial Transmission and Replication Kinetics of West Nile Virus Lineage 1 in Laboratory Reared Ixodes ricinus Ticks

Cristian Răileanu et al. Pathogens. .

Abstract

West Nile virus (WNV) is a mosquito-borne agent that has also been isolated from several tick species. Vector competence of Ixodes ricinus, one of the most common tick species in Europe, has been poorly investigated for WNV to date. As such, to evaluate the vector competence, laboratory reared Ixodes ricinus nymphs were in vitro fed with WNV lineage 1 infectious blood, allowed to molt, and the resulting females artificially fed to study the virus transmission. Furthermore, we studied the kinetics of WNV replication in ticks after infecting nymphs using an automatic injector. Active replication of WNV was detected in injected nymphs from day 7 post-infection until 28 dpi. In the nymphs infected by artificial feeding, the transstadial transmission of WNV was confirmed molecularly in 46.7% of males, while virus transmission during in vitro feeding of I. ricinus females originating from infected nymphs was not registered. The long persistence of WNV in I. ricinus ticks did not correlate with the transmission of the virus and it is unlikely that I. ricinus represents a competent vector. However, there is a potential reservoir role that this tick species can play, with hosts potentially acquiring the viral agent after ingesting the infected ticks.

Keywords: Ixodes ricinus; West Nile virus; arbovirus; transstadial persistence.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
West Nile virus (WNV) titre in Ixodes ricinus nymphs injected by percoxal route at different timepoints. The horizontal black lines represent the medians, the x indicates the mean, the boxes show the interquartile ranges and the whiskers indicate the minimum and maximum values. The number of samples tested per timepoint is indicated above the x-axis.
Figure 2
Figure 2
WNV titre in supernatants of Vero cells inoculatd with homogenates of Ixodes ricinus nymphs injected by percoxal route at different timepoints. The horizontal black lines represent the medians, the x indicates the mean, the boxes show the interquartile ranges and the whiskers indicate the minimum and maximum values. The number of samples tested per timepoint is indicated above the x-axis.
Figure 3
Figure 3
Viral RNA titres of WNV in Ixodes ricinus males. Different groups indicate the different FUs in which nymphs that molted into adult males were infected with WNV by in vitro feeding. The number of samples are indicated above the x-axis. Horizontal black lines are representing the medians, the x indicates the mean, the boxes show the interquartile ranges and the whiskers the minimum and maximum values.
Figure 4
Figure 4
Viral RNA titres of WNV in Vero supernatants of Ixodes ricinus males. Different groups indicate the different feeding units (FUs) in which nymphs that molted into adult males were infected with WNV by in vitro feeding. The number of samples are indicated above the x-axis. Horizontal black lines are representing the medians, the x indicates the mean, the boxes show the interquartile ranges and the whiskers the minimum and maximum values. The values outside the interquartile ranges are represented as outliers.
Figure 5
Figure 5
Experimental work for the vector competence study of Ixodes ricinus for WNV lineage 1.
See this image and copyright information in PMC

References

    1. Chancey C., Grinev A., Volkova E., Rios M. The global ecology and epidemiology of West Nile virus. Biomed. Res. Int. 2015;2015:376230. doi: 10.1155/2015/376230. - DOI - PMC - PubMed
    1. Campbell G.L., Marfin A.A., Lanciotti R.S., Gubler D.J. West Nile virus. Lancet Infect. Dis. 2002;2:519–529. doi: 10.1016/S1473-3099(02)00368-7. - DOI - PubMed
    1. Kolodziejek J., Marinov M., Kiss B.J., Alexe V., Nowotny N. The complete sequence of a West Nile virus lineage 2 strain detected in a Hyalomma marginatum marginatum tick collected from a song thrush (Turdus philomelos) in eastern Romania in 2013 revealed closest genetic relationship to strain Volgograd 2007. PLoS ONE. 2014;9:e109905. doi: 10.1371/journal.pone.0109905. - DOI - PMC - PubMed
    1. Hoogstraal H., Clifford C.M., Keirans J.E., Kaiser M.N., Evans D.E. The Ornithodoros (Alectorobius) capensis group (Acarina: Ixodoidea: Argasidae) of the palearctic and oriental regions. O. (A.) maritimus: Identity, marine bird hosts, virus infections, and distribution in western Europe and northwestern Africa. J. Parasitol. 1976;62:799–810. doi: 10.2307/3278964. - DOI - PubMed
    1. Lvov D.K., Timopheeva A.A., Smirnov V.A., Gromashevsky V.L., Sidorova G.A., Nikiforov L.P., Sazonov A.A., Andreev A.P., Skvortzova T.M., Beresina L.K., et al. Ecology of tick-borne viruses in colonies of birds in the USSR. Med.Biol. 1975;53:325–330. - PubMed