Re: West Nile Fever In Italy, Equine
Re: West Nile Fever In Italy, Equine
WEST NILE VIRUS - ITALY (02): (FERRARA)
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A ProMED-mail post
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Date: 25 Sep 2008
Source: Eurosurveillance V13 (No 39) Rapid Communications [edited]
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http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=18990>
There have been 6 confirmed and 5 suspected cases of West Nile virus
infection in horses reported in the vicinity of Ferrara in Italy. To
verify the diffusion of viral circulation and to prevent the spread
of disease, the regional authorities of Emilia-Romagna adopted a
special plan of West Nile fever surveillance.
Detection of cases
As of 22 Sep 2008, 12 horses with neurological symptoms indicating
the possibility of West Nile virus infection have been reported. The
notifications were made in accordance with the already existing
national surveillance of West Nile disease. In 6 of these cases, the
diagnosis was confirmed by laboratory analysis performed at the
national reference centre (Centro di Referenza Nazionale per le
Malattie Esotiche - CESME); for 5, the initial ELISA test was
positive, but the confirmation is still pending, and one tested
negative. The infected horses belong to 8 different stables, 7 in the
province of Ferrara and one in the province of Bologna at the border
with Ferrara. There are about 220 horses kept in these stables, and
all are to be tested for West Nile virus infection. The blood
sampling and laboratory testing is currently ongoing.
West Nile virus has also been recently detected in wild birds in the
area. Although no anomalous mortality has been signaled, surveillance
of wild birds conducted between 19 Aug-14 Sep [2008] in the framework
of a general monitoring of the regional wild fauna resulted in
detection of West Nile virus in 6 crows and 7 magpies [presumably
European crows (_Corvus corone_) and European magpies (_Pica pica_).
- Mod.TY] all from the province of Ferrara.
To date, there have been no human cases of West Nile fever reported
in Italy. Active surveillance of cases of meningoencephalitis (with
clear cerebrospinal fluid [CSF]) was started on 16 Sep [2008] and is
ongoing. So far, one suspected case was notified in a patient
resident in the province of Bologna near the border with Ferrara.
However, the results of laboratory analysis are still pending.
Control measures
The public health authorities in Emilia-Romagna are closely
monitoring the situation and adapting the action plan to the evolving
epidemiological situation. Currently, the following measures are in
place or planned:
Veterinary surveillance
The veterinary surveillance which started on 15 Sep [2008] comprises
passive surveillance (until 31 Oct 2008) and active surveillance
(until 31 Dec [2008]) of cases of West Nile fever in horses. It is
also foreseen that samples collected from cattle in the region as
part of sentinel surveillance for bluetongue disease will be tested
for West Nile virus. Furthermore, a national plan for surveillance of
wild birds (other than corvids) is under preparation.
Human surveillance
The surveillance of human cases ongoing since 15 Sep [2008] includes
rapid detection and reporting of cases with neurological symptoms
compatible with West Nile disease (until 31 Oct [2008]), as well as
active surveillance among employees of stables where cases of
infection in horses have occurred, promoting the awareness on this
disease, preventive measures, and early detection of West Nile fever.
The case definition used includes patients older than or equal to 15
years old with fever greater than or equal to 38.5 C and neurological
symptoms: encephalitis, meningitis or Guillain-Barre syndrome or
acute flaccid paralysis. Cases are classified as:
a) possible: clinical symptoms and clear CSF;
b) probable: clinical symptoms and at least one of the following
laboratory criteria: presence of IgM antibodies against West Nile by
ELISA; seroconversion by ELISA; 4-fold increase of IgG antibodies
against West Nile in 2 consecutive (greater than 5 days, preferably
15-20 days) samplings by ELISA;
c) confirmed: clinical symptoms and at least one of the following
laboratory criteria: isolation of West Nile virus in blood or CSF;
presence of IgM antibodies in CSF (by ELISA); detection of nucleic
acid specific for West Nile virus by RT PCR in blood or CSF;
detection of increased levels of IgM and IgG antibodies against West
Nile by ELISA confirmed by neutralization testing.
At the moment, considering the surveillance measures adopted as well
as the example of other countries, especially France [1], the Italian
authorities decided not to introduce any restrictions on blood
donations. However, the situation is monitored closely, and, should a
human case be confirmed, this decision will be reconsidered.
Vector surveillance and control
In addition to surveillance, vector control measures are being
implemented in the area affected, i.e. the province of Ferrara and
the border zones of the provinces of Ravenna, Bologna and Modena. In
these areas, samples of mosquitoes (_Culex_ spp. and _Aedes_ spp.)
are being collected; 10 000 catchments divided into pools are going
to be analysed (by PCR). In addition to larvicide disinfestations in
every potential breeding site, adulticides interventions are planned
to be undertaken in every urban area and on the occasion of open-air
public gatherings, e.g. fairs and festivals, especially held outside
the urban centres and in the vicinity of water reservoirs.
Conclusion
This event illustrates the necessity of a coordinated strategy plan
combining surveillance in domestic animals, wild fauna and in humans
for assessing the magnitude of the outbreak and for an efficient management.
References
1. Zeller H, Zientara S, Hars J. West Nile outbreak in horses in
Southern France: September 2004. Euro Surveill. 2004;8(41)
ii=2564.
Available online:
<
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=2564>.
Citation for the above article: Macini P, Squintani G, Finarelli AC,
Angelini P, Martini E, Tamba M, Dottori M, Bellini R, Santi A, Loli
Piccolomini L, Po C. Detection of West Nile virus infection in
horses, Italy, September 2008. Euro Surveill. 2008;13(39)
ii=18990.
Available online:
<
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=18990>.
--
Communicated by:
ProMED-mail <
promed@promedmail.org>
[This report provides the specific information concerning this West
Nile virus (WNV) outbreak requested in the ProMED posting given
below. It underscores the need for comprehensive approaches by
interdisciplinary teams. Interestingly, _Aedes_ mosquitoes are being
collected and tested. Central Italy suffered an outbreak of
chikungunya virus infections transmitted by the Asian tiger mosquito,
_Ae. albopictus_. It will be interesting to see whether _Ae.
albopictus_ becomes implicated as a WNV vector in this outbreak.
ProMED Rapporteur Joseph Dudley provided the following comment
regarding this mosquito and West Nile virus transmission: "_Aedes
albopictus_ has been isolated from mosquitoes in the field in North
America (Holick et al 2002, CDC 2006), and shown experimentally to be
a competent vector of West Nile virus" (Sardelis et al 2002,
Tiawsirisup et al. 2005, Chu et al 2005).
Although this species is not considered a principal vector of WNV
transmission, vertical transmission of WNV has been demonstrated in
this species (Baqar et al 1993).
References:
Michael R. Sardelis, Michael J. Turell, Monica L. O'Guinn, Richard G.
Andre, And Donald R. Roberts. 2002. Vector Competence Of Three North
American Strains Of Aedes Albopictus For West Nile Virus. Journal of
the American Mosquito Control Association 18: 284-289 (December 2002)
<
http://apt.allenpress.com/perlserv/?request=get-abstract&doi=10.1043%2F8756-971X(2002)018[0284%3AVCOTNA]2.3.CO%3B2&ct=1>.
Shahida Baqar, Curtis G. Hayes, James R. Murphy and Douglas M. Watts.
1993. Vertical Transmission of West Nile Virus by Culex and Aedes
Species Mosquitoes. Am. J. Trop. Med. Hyg., 48(6), 1993, pp. 757-762
<
http://www.ajtmh.org/cgi/content/abstract/48/6/757>.
Sonthaya Tiawsirisup, Kenneth B. Platt, Richard B. Evans, Wayne A.
Rowley. 2005. A Comparison of West Nile Virus Transmission by
Ochlerotatus trivittatus (COQ.), Culex pipiens (L.), and Aedes
albopictus (Skuse) Vector-Borne and Zoonotic Diseases 5(1): 40-47
<
http://www.liebertonline.com/doi/abs/10.1089/vbz.2005.5.40>.
John Holick, Andrew Kyle, William Ferraro, Raymond R. Delaney, And
Marta Iwaseczko. 2002. Scientific Note: Discovery Of Aedes Albopictus
Infected With West Nile Virus In Southeastern Pennsylvania. Journal
of the American Mosquito Control Association 18: 131-131 (June 2002)
<
http://apt.allenpress.com/perlserv/...&issn=8756-971X&volume=018&issue=02&page=0131>.
J J H Chu, P W H Leong, M L Ng 2005. Characterization of plasma
membrane-associated proteins from Aedes albopictus mosquito (C6/36)
cells that mediate West Nile virus binding and infection. Virology.
2005 Sep 1;339 (2):249-60.
CDC 2006. Mosquito Species producing WNV positives by year 2002-2006
<
http://www.cdc.gov/ncidod/dvbid/westnile/mosquitospecies.htm>.
A map showing the location of Ferrara province and vicinity in Italy
can be accessed at
<
http://www.pickatrail.com/jupiter/location/europe/italy/ferrara.html>.
- Mod.TY]
[see also:
West Nile virus - Italy: (FE)
20080919.2933]
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