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Published Date: 2011-12-25 20:44:47
Subject: PRO/AH> Schmallenberg virus - Europe (09): Update
Archive Number: 20111225.3674

SCHMALLENBERG VIRUS - EUROPE (09): UPDATE
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Date: Sun, 25 Dec 2011
From: Charles H Calisher <calisher@cybersafe.net>

Subject: Schmallenberg virus, epidemiology (comment)

Culicoids have been in Europe for a very long time and have been
tested for bluetongue and other viruses. Given that top-notch
European veterinary virologists have not detected the disease
Schmallenberg virus causes, that this virus now has appeared so far
in three countries there (Germany, The Netherlands and Belgium), that
the only orthobunyavirus isolated from culicoids in Europe is Tahyna
virus (1) (a member of the California serogroup), and that no Simbu
group virus has been isolated in Europe, this virus may be a recent
introduction, but from where? Many Simbu group viruses are known to
infect birds, so that infected migrating birds may have served as a
recent source, perhaps from Africa.

Consideration that this virus was intentionally introduced may be
paranoid and unlikely but must be ruled out, if possible. Could be a
trial balloon.

Reference
(1) Halouzka J, Pejcoch M, Hubalek Z and Knoz J (1991)
Isolation of Tahyna virus from biting midges (Diptera,
Ceratopogonidae) in Czecho-Slovakia. Acta Virol. 35:247-251.

Charles H. Calisher, Ph.D.
Professor Emeritus, Arthropod-borne and Infectious Diseases
Laboratory
Department of Microbiology, Immunology and Pathology
3195 Rampart Rd., Delivery Code 1690, Foothills Campus
Fort Collins, CO 80523-1690
College of Veterinary Medicine and Biomedical Sciences
Colorado State University
e-mail: <calisher@cybersafe.net>

[Prof Calisher, a world authority on bunyaviruses, is gratefully
acknowledged for reminding us the potential of birds as virus
spreaders. Hopefully, this issue will be included in the
epidemiological investigations.

How long is MBV circulating in the region, where did it come from and
how, and how wide has it been spread since its introduction, are
enigmatic issues. Similarly enigmatic, and rather worrying, is the
unsolved issue of the introduction of another vectorborne virus,
BTV-8, which appeared in the very same region in the summer of 2006
while its origin and route of introduction are still to be deciphered.

Out of 46 Dutch locations which have already reported abnormal newborn
lambs, the SBV has been identified, as of 23 Dec 2011, on 4 farms;
their locations are available in the map at
http://www.vwa.nl/txmpub/files/?p_file_id=2201854. The distance
between the most northern location, Zwolle, and the southernmost one,
Maastricht (on the Belgian border) is approximately 200 km.

One of the various potential routes of arthropod vectors introduction
into the Netherlands (a tire shipment) has been recently described
(see ref 1).

References
1. Julia E. Brown , Ernst-Jan Scholte, Marian Dik et al (2011). Aedes
aegypti Mosquitoes Imported into the Netherlands, 2010.
Emerging Infectious Diseases, Vol. 17, No. 12, December 2011. -
Mod.AS

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