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[OUTBREAK:003297]
ProMED概要 20040802-0010..20040803-0010
●06-01(0802-0040)#Ea#馬インフルエンザ、イヌ-米国（フロリダ州）#
情報源：DVM
Magazine、6月1日。
フロリダ大学の研究者らが馬インフルエンザウイルスに対するイヌの感受性を示した。
フロリダ大学(UF)獣医学研究者らが初めて、馬インフルエンザが種の壁を超えてイヌにも感染することを示した。（以下、フロリダ州Jacksonvilleのイヌ飼育場で8頭のグレイハウンド犬が死亡した呼吸器疾患の原因が馬インフルエン
ザウイルスである可能性を指摘する記載、後略。）
[Moderator注：馬インフルエンザウイルス1
型(H7N7)は1956年にヨーロッパで分離され、その後米国で分離された。2例目の馬インフルエンザウイルス(H3N8)
は1963年に米国で分離され、その後世界各地で分離されている。馬インフルエンザウイルス2型(H3N8)は最近の流行の大部分の病因であり、遺伝子配列検査
ではこのウイルス株が最初に分離されて以来わずかしか変異していないことが
示されている。これまでのところ、イヌでは特異的インフルエンザウイルスは確認されていない。1989年に中国東北部のウマで発生した、インフルエンザA
ウイルスの深刻な流行は、広く流行している馬インフルエンザウイルスと同じ
抗原性を持ったウイルス株が原因であった。しかし、その際の病因ウイルスの別の遺伝子が鳥起源であったことから、遺伝子組み換え株の様であった。発病
したグレイハウンドから検出されたウイルスが、単に種の壁を越えて感染した馬インフルエンザウイルスであるのか、他の起源から遺伝子を獲得した組み換
え株であるのかを確認するのが重要であろう。こうした情報はこのイヌのウイルス株がヒトに感染伝播する可能性を評価するのにも重要となろう。]
［もどる］
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EQUINE
INFLUENZA, CANINES - USA
(FLORIDA)
*****************************************
A
ProMED-mail post
ProMED-mail, a program of the International
Society for Infectious Diseases
Date: 1 Jun 2004
From:
ProMED-mail
Source: DVM Magazine [edited]
UF researchers
link equine influenza virus to canine
susceptibility
-----------------------------------------------
For
the 1st time, University of Florida (UF) veterinary researchers
believe they have documented cases of equine influenza virus jumping
the species barrier into dogs.
The virus is the likely cause
of a respiratory disease outbreak that killed 8 racing Greyhounds
from kennels in Jacksonville. Although the outbreak has been
isolated and quashed, any time a virus jumps species it is
considered an important epidemiological event, the university
reports.
Although researchers stress the findings involve
only these particular Jacksonville dogs, they will investigate
possible connections to similar disease outbreaks that have affected
racing dogs in Florida and elsewhere in recent years.
Cynda
Crawford, DVM, Ph.D., a UF veterinary immunologist, explains, "I
want to stress that our team's findings are preliminary and confined
to the dogs affected by an outbreak at one Florida track, an
outbreak that occurred 3 months ago and was contained through a
voluntary statewide quarantine, which is no longer in effect."
UF's research team also worked with Cornell University's
College of Veterinary Medicine in Ithaca, N.Y., and the Centers for
Disease Control and Prevention (CDC). Ed Dubovi, director of
virology section at Cornell's Animal Health Diagnostic Lab isolated
the virus. CDC was brought in to assess the public health threat and
monitor the outbreak.
"The virus found in the canine samples
is probably representative of the strain that is circulating now in
horses in Florida and elsewhere in the United States," says Ruben
Donis, Ph.D. with CDC.
On the basis of genetic sequencing,
Donis and colleagues at the Influenza Branch conclude the virus
found in canine samples resembled a strain of equine influenza virus
that appeared in horses in Wisconsin during 2003.
The
researchers also found that the dogs developed antibodies specific
for the influenza virus.
"This implies that the virus
replicated enough within the dogs for their immune system to
recognize it and form antibodies," Crawford says.
Equine
influenza is a disease of horses and is present in North America,
Europe and parts of Asia. Horses typically develop a fever and a
dry, hacking cough. In the early stages of the disease, horses are
reluctant to eat or drink for several days, but usually recover in
2-3 weeks.
Crawford adds that she is unsure how the
Jacksonville Greyhounds could have been exposed to equine influenza
virus, and that is one of many questions they intend to pursue
through further epidemiological studies.
When Crawford
learned about the January outbreak, she visited the Jacksonville
track to find 24 dogs affected with symptoms including cough, fever
and other more serious symptoms. Out of the total, 8 dogs died and
16 recovered.
Crawford reports she collected blood and nasal
fluid samples from 35 dogs, and 5 of the dogs that died underwent
postmortem examinations.
The team also alerted dog owners not
to experiment with prevention products approved for other species
because of the potential for adverse reactions, including
death.
[Details of the story provided by Sarah Carey,
University of Florida.]
--
ProMED-mail
[Equine
influenza virus 1 (H7N7) was isolated in Europe in 1956 and
subsequently in the USA. Then a second equine influenza virus (H3N8)
was isolated in 1963 in the USA and subsequently elsewhere in the
world. Equine influenza virus 2 (H3N8) has been responsible for the
majority of recent outbreaks and sequencing studies indicate that
equine influenza virus 2 virus has undergone only slight genetic
drift since first isolation. No influenza virus has been designated
as specific to canines so far. In 1989 a severe outbreak of
influenza A virus infection in horses in northeastern China was
caused by a virus withe the same antigenicity as the prevalent
equine influenza virus. However, it appeared to be a reassortant as
its other genes were of avian origin. It will be important to
establish whether the virus recovered from the affected greyhounds
is an equine virus that has simply jumped species, or whether it is
a reassortant virus that has acquired genes from another source.
This information will be important in accessing the potential of
this canine virus for transmission to humans. - Mod.CP]
[see
also:
Undiagnosed illness, canine - USA (FL)(02)
20040730.2081
Undiagnosed illness, canine - USA (FL)
20040701.1753]
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