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August 2007 • VOLUME 24 • © HORSES For LIFE™ Magazine
The Associated
Press reported on 08.25.07, 7:01 AM ET an outbreak of equine influenza.
An outbreak that could have serious ramifications as it is the first
time in Australia’s history.
SYDNEY, AUSTRALIA -
“Racetracks across Australia were all but shut down Saturday, the
country's richest horse race is in doubt and losses could total more
than a billion dollars after an outbreak of equine influenza.
The highly contagious equine virus was discovered in 11 non-racehorses
at the Centennial Park complex adjoining Sydney's Royal Randwick
racecourse. Five horses at a second Sydney facility also showed
symptoms of the disease.
Racing was canceled Saturday across Australia except on the island
state of Tasmania and in the Northern Territory as agriculture
officials expanded to 6 miles an exclusion zone around the Centennial
Park stables and banned all movement of horses within New South Wales
state.
New Zealand officials later banned imports of Australian horses, and
the Melbourne Cup, traditionally held on the first Tuesday in November,
was in danger of being postponed.”
“Agricultural Minister Peter McGauran said the equine flu outbreak was
the biggest risk ever faced by the Australian thoroughbred industry.
"We've never had an introduction of influenza in the equine population
of Australia ever before ... If it was to escape beyond the stable of
the horses in Centennial Park, it would have a devastating effect on
the horse population," McGauran said.
Equine influenza was first detected Thursday at separate facilities in
New South Wales and Victoria, where some of the world's most valuable
thoroughbred stallions had been imported from Britain for the
Australian breeding season.
The imported stallions were to serve some 30,000 mares during the
course of the season, and their unavailability - coupled with the
cancellation of race meetings - was forecast to cost the racing
industry billions of dollars.
Most of the impounded horses are thoroughbred stallions with an estimated collective value of more than $400 million.’
Copyright 2007 Associated Press. All rights reserved.
As to where the "bug" came from — and who is responsible for bringing it in?
No one wants to point the finger .....
Yesterday the $8 billion industry that supplies 74,000 jobs in Victoria
alone was still in shock, coming to grips with a calamity growing more
serious by the hour.
Although equine influenza is endemic in Britain and Ireland, and in
Europe generally, it is Japan that has suffered an outbreak in the past
fortnight — closing down Japanese racing in what could be a worst-case
scenario for Australia at the beginning of the peak spring season.
Any one of 13 stallions that had been "shuttled" from Japan could have
carried the virus back on a flight. When the Japanese shipment joined
another shipment of horses from the UK and Ireland at a stopover —
probably in Hong Kong — the virus could have spread to any one of them.
So what happened next? Nine of the 13 horses from Japan were
quarantined at Spotswood in Melbourne, while the other four went to
Eastern Creek quarantine station near Sydney. It seems (pending tests)
that the "Melbourne nine" might be in the clear — but it was clear that
Sydney was in big trouble, presumably because one of the four stallions
sent there was carrying the virus. Which meant, automatically, that
more than 40 horses in quarantine with them had to be locked up to
prevent it getting out.
But it was already too late.
On Friday, veterinary officers confirmed that several pleasure horses
stabled at Sydney's Centennial Park had equine flu symptoms.
By last night, a veterinarian confirmed that 200 "hacks" at Centennial
Park were showing symptoms — which explains why a 10-kilometre horse
exclusion zone has been thrown up around the park and nearby Randwick
Racecourse, hub of NSW racing.”
Equine Influenza has
caused major havoc in all horse orientated pastimes here in Australia
over the weekend. The outbreak has resulted in a nightmare for the
racing industry and all events organisers. There is currently a nation
wide lockdown on horse movements. It is recommended that horses are not
taken out of their pastures and it is against the law to float (aka
trailer) them ANYWHERE.
One personal viewpoint of the events posted on an Australian Board
employee who wrote on an Aussie equine
forum about her first hand experience managing EI in the horses at the
Sydney based
Centennial
Park stables.
“Had an absolute shocker of a week at work (I work at
Centenial
Park in the city)
Wednesday/Thursday had a horse in one stable block come
down with the flu, had a temp of over 40 oC...had vet out. By Thursday morning
we had maybe 6-10 horses with coughs and high temps and one of our horses off
his feed.
Friday morning all 12 horses in out stable block, 16
horses in the next stable block and 6 in the one over all suffering from a
cough.
The horse I look after his temp soared from 37.5 to
39.8-40.01 within the day, had muscle spazms, sweating & cough. Vets were
already there treating horses. By the end of the day all the horses I look
after had temps in EXCESS of 39 oC (remembering a normal temp is between 37.5-38.5)
and I look after 12-14 horses.
By Friday night quarantine was out and took 10 samples
from horses showing symptoms. EVERY one of those samples came back positive for
equine influenza. The papers are saying that only 10 horses at the centre have the
virus. This is VERY untrue. There are 180 horses in the stables and I would say
there would be in excess of 70-80 horses MIN with the virus and its spreading
VERY quickly.
Was advised all lessons were cancelled and horses
stabled. Also horses were not to leave the centre under any circumstance. 6
horses had left that morning and were tracked down and quarantined at parks.
Arrived at work this morning and the whole complex was
taped off, plastic sheets were put around the whole place and guards were at
the door. Plus countless other photographers, camera men and all that jazz. We
now have to sign in and shoes have to be changed at the entrance. Only
authorized personel are allowed in the complex. On exiting you have to be
disinfected and boots scrubbed clean.
Nothing can be taken away from the centre and we
already have a problem of manure, as all the bins are full and the waste man
cant come and collect it. So its being dumped and hopefully they will organise
some special skips to be bought into the centre so it can be taken away and
burnt.
All shows (some of which were on today...i think
penrith and some arab show + more) have been cancelled and horses are to be
taken straight home. Pretty much all boarding stables/riding schools have been
shut down to the point of no new horses onto the property and no outside
instructors so that no cross contamination is found.
Mounted police at Redfern have also been locked down
and
Randwick
race course also.
No horses can leave the complex for a further 30 days AFTER
the LAST horse is cleared of illness. This could be a min of 2 months. This
isnt a good thing when States, Nationals and Equitana (dressage wise) are all
coming up... The horses cant be worked and only walked up and down the isles of
the stable blocks (not very much at all!). Horses that have been boxed for 2
days are already VERY fresh but they are too sick to be worked.
The riding schools will most likely be shut down for
min of 30 days, which is a huge financial loss which some possibly cant stand,
and who knows what kind of compensation they will get if any!
Quarantine/Vets really cant say much about it because
they in all honesty dont know what it is...they even said they are unsure if it
can be passed to humans (a few of the ppl out there inc myself have all come
down with coughs etc...hopefully its VERY unrelated).
Alot of people are saying this is just the start of
something alot bigger.
I've been told I'm unable to touch/be in contact with
any other horses off the complex for at least 30 days
Just thought you might be interested in an insiders
view.
Names: EI, Equine Influenza
Causes: Like humans, the flu is caused by a virus and spreads in much
the same way-through airborne particles, or buckets, troughs, hands or
other items that may carry the virus. The virus can spread very quickly.
Effects: Most horses make a full recovery from Equine Influenza.
Occasionally, secondary infections such as pneumonia may set in and
lung or heart damage may occur.
Prevention: Vaccination is the best preventative against Equine
Influenza. Maintain good stable hygiene that includes sterilizing
buckets, feed tubs and other equipment and taking precautions like hand
washing, to prevent spread of the virus.
What is the incubation time?
Most horses exposed to the virus will show signs within a period of 1-5 days.
What are the signs of influenza?
Equine influenza appears similar to a range of other viral respiratory
diseases. Viruses that are responsible for coughs and colds in
Australia include Equine Herpesvirus, Equine Rhinovirus and Equine
Adenovirus. Most of these viruses produce rather mild signs which
include a discharge from the nose and coughing. Equine Influenza
produces more severe symptoms with horses developing a fever and a dry
hacking cough. Horses become ill and are reluctant to eat or drink for
several days but usually recover in 2 to 3 weeks.
How is influenza virus spread?
The virus can be spread easily from horse to horse as a result of
droplets and also from nasal discharge and from things like infected
brushes and rugs. The disease is very contagious and there is almost
100% infection rate in a population that has been previously unexposed
to the virus.
A recent paper published in an English Veterinary Journal (DG Powell,
KL Watkins, PH Li, and KF Shortridge Outbreak of equine influenza among
horses in Hong Kong during 1992. Veterinary Record Vol. 136, 1995 pg.
531) has some important lessons for Australia. In 1992, an outbreak of
influenza occurred among horses stabled at the Royal Hong Kong Jockey
Club, even though all the racehorses in Hong Kong are vaccinated
against influenza. About 37% of the 955 horses stabled in the racing
stables at Hong Kong showed signs of the disease. The most severely
affected horses were those imported from countries where the disease
does not occur. The authors concluded that while vaccination did not
prevent influenza, the disease in vaccinated horses was less severe and
the signs lasted a shorter period than when horses are unvaccinated.
This highlights the need for more effective influenza vaccines.
Training was stopped when horses showed signs of influenza, which
appeared to reduce the severity of the disease. The outbreak had a
severe effect on racing in Hong Kong with the postponement of 7 race
meetings over a period of 32 days.
About Equine Influenza
What is the Equine Influenza incident?
An equine influenza infection is highly suspected in horses stabled in Sydney in two locations.
What is Equine Influenza?
Equine influenza (EI) is an acute, highly contagious, viral disease
which can cause rapidly spreading outbreaks of respiratory disease in
horses, donkeys, mules and other equine species. EI is exotic to
Australia and would have a major impact on the Australian horse
industry if it were to become established here.
How is EI spread?
The virus is usually spread by:
• direct contact between infected and susceptible horses
•
• indirect contact with contaminated tack or equipment
•
• susceptible horses occupying buildings or vehicles recently occupied by diseased horses
•
• close contact between contaminated horse handlers and healthy horses.
•
Can people catch EI?
Transmission of EI virus to humans has not occurred during outbreaks of EI in horses.
Equine influenza poses no threat to people, however it can be spread from people to horses via infected clothing.
How can I tell if my horse has EI?
The main clinical signs of EI are usually a sudden increase in
temperature (to between 39°C and 41°C); a deep, dry, hacking cough; and
a watery nasal discharge, which may later become thick and smelly.
Other signs can include depression, loss of appetite, laboured breathing, and muscle pain and stiffness.
Few adult horses die of the disease but it can kill young foals.
Recovery usually occurs after a couple of weeks but horses need to be
rested for a further period to avoid complications.
Treatment
What is the treatment for EI?
• There is no specific treatment other than rest and supportive treatment for the fever and cough.
•
• Horses that are worked or stressed while sick or
during recovery may develop secondary bacterial bronchitis or
bronchopneumonia and die.
•
• Horses should be rested for at least one week for
every day of coughing eg. if the horse coughs for 5 days, rest it for 5
weeks.
•
What will happen if my horse is infected?
All infected properties are being placed in quarantine to ensure that
the affected animals do not move and the disease does not spread.
Quarantines will be maintained until at least 30 days after the last
signs are seen in affected horses.
Are infected horses killed?
Horses are not killed. Infected horses or donkeys are quarantined in order to prevent spread of the disease.
Is there a vaccine available?
There are vaccines overseas but none will be available for use in the
short term, especially since vaccination can complicate the diagnosis
of the disease. We hope to eradicate the infection so permanent
vaccination or horses in Australia will not be required.
Protecting your Horse(s) and Property
How can I protect my horse?
• Keep your horse away from other horses.
•
• If you have contact with other horses scrub your
footwear in disinfectant, shower and change your clothes before
handling your horse.
•
• If you have contact with a sick horse do not go near another horse for 72 hours.
•
How do I protect my property from possible infection?
Before entering or leaving any premises holding horses, horse owners or handlers should:
• wear clothes and footwear which have had no contact with horses
•
• if there is any doubt, clothes should be laundered
in a hot wash or dry-cleaned and footwear be cleaned and disinfected.
•
• shower or wash using plenty of warm water and soap, and
•
• clean and disinfect any item or equipment that may
have been in contact with horses including horse transport vehicles.
•
People having no contact with horses need take no special precautions.
What about my feed delivery?
Non-essential vehicles and visitors must be prevented from entering
areas of the premises that hold horses. Arrange whenever possible for
collection and delivery of supplies to take place at the boundary of
the premises.
Should I cancel my farrier/chiropractor/massage therapist/dentist?
Access to properties should only be allowed if the matter is an
emergency. Where possible do not make arrangements for these types of
visits until after the stock standstill has been lifted.
Where visits do take place ensure appropriate disinfection occurs by the property owner and the visitor.
How do I disinfect my gear?
Equine influenza virus can easily be killed by vigorous cleaning and
disinfection of potentially contaminated hands, clothing and objects
and is rapidly inactivated by exposure to ultraviolet light.
A dirty surface must always be cleaned thoroughly before it can be
satisfactorily disinfected. Organic material such as dirt, manure and
straw may neutralise the disinfectant and make it useless.
It is therefore most important that anything that must be disinfected
is first thoroughly washed and cleaned and finally washed down or
sprayed with an approved disinfectant.
Bleach, diluted as per the manufacturer’s recommendation, is a suitable disinfectant.
Specific agents to kill viruses are available. Please consult your veterinarian for further information.
As disinfectants and chemicals can be irritant, persons handling them
should always read the product label and follow the manufacturer’s
instructions, and wear protective clothing as necessary.
If my horse is infected, how do I dispose of contaminated bedding or feed?
Contaminated materials from stables can be disposed of by burning
(where approved), by burial or by composting. The virus that causes
equine influenza does not survive long in the environment.
Do carrrier animals exist?
No. Once an animal has recovered and a sufficient time (30 days) has elapsed they pose no risk to other horses.
Response Activities
The suspected outbreak response is being carried out in accordance to the Equine Influenza AUSVETPLAN Manual PDF [1.2mb]
Why is controlling the equine influenza outbreak important?
EI would have a major impact on livestock health and on the horse
industry if it were to become established in the horse population. All
horses will be permanently at risk of infection with subsequent impacts
on competitive and domestic activities.
I am likely to lose money because of this disease. Can I seek compensation?
No, there is no compensation for loss of income or production. These
controls are intended to benefit the whole industry, including domestic
horse owners, in the long term.
Who is paying for the control activity?
All emergency animal diseases, such as equine influenza, are
cost-shared under existing agreements between government and the
relevant industries. Initial activities are undertaken by the lead
agency, in this case the NSW Department of Primary Industries.
Backgrounder: Equine influenza
November 13, 2006
Printer-friendly version (PDF)
Causative agent
Equine influenza (EI) is caused by a type A Orthomyxovirus. The viruses
are 80 to 120 nanometers (nm) in diameter, and consist of a core of
eight separate segments of single-strand ribonucleic acid (RNA)
surrounded by a spiked arrangement of glycoproteins. These viruses are
classified based on the relative numbers of hemagglutinin (H) and
neuraminidase (N) glycoproteins in the lipid outer layer. Strains (or
subtypes) of influenza viruses are formally described according to
their type (A, B, or C), host species, location of first isolation
(city or country), strain number (if any), year of first isolation, and
antigenic subtype (H and N designation); shorthand methods of
identification are limited to the H/N description. The two major
strains known to cause disease in equids are H7N7
(A/eq/Prague/56[H7N7], type A influenza, equine, first isolated in
Czechoslovakia in 1956) and H3N8 (A/eq/Miami/2/63[H3N8], type A
influenza, equine, first isolated in Miami, strain 2, isolated in
1963). The two subtypes are immunologically distinct. Sublineages of
the two major strains (e.g., A/eq/Newmarket/2/93[H3N8],
A/eq/Kentucky/92[N3H8]) have emerged due to antigenic shift
(reassortment of the genome resulting in genetic alteration) and
antigenic drift (point mutations in the genetic code causing minor
alterations in the H and N glycoproteins).
Natural distribution
Equine influenza affects horses, donkeys, mules, and other equidae. The
virus is widespread with only Iceland, New Zealand, and Australia
considered to be free of the virus. The H7N7 subtype is believed to be
extinct or present at very low levels. The H3N8 subtype appears to be a
mutation of an avian influenza virus.
An outbreak involving a modified H3N8 subtype (designated
A/eq/Jilin/89[H3N8]) occurred in China in 1989. High morbidity (80%)
and mortality (20%) were observed. Other important outbreaks of the
H3N8 subtype have occurred worldwide, including in Trinidad (1979),
Argentina (1985), South Africa (1986), and Jamaica (1989). Most
confirmed outbreaks occurred at racetracks; as a result, horseracing
activities were suspended for prolonged periods of time, resulting in
marked economic losses.
Transmission
Equine influenza is spread via aerosolized respiratory secretions and
fomites, including contaminated inanimate objects and people moving
between infected and uninfected horses. The most common source of
infection and outbreak is the introduction of a new animal into the
herd. The incubation period is usually one to three days. Incubation
periods approaching seven days have been observed, but are less common.
Infected horses shed virus in their respiratory secretions during the
incubation period, and continue to excrete the virus for four to five
days after clinical signs are observed. It is also possible for an
infected animal to shed the virus for 7-10 days after the animal has
appeared to recover. Viral shedding is thought to reach its peak during
the first 24 to 48 hours the animal is febrile. Infected droplets may
be able to spread as far as 50 yards. Virtually 100% of horses that are
exposed become infected. Nearly 20% of infected horses do not exhibit
clinical signs of disease, but still shed virus and can spread the
infection.
Clinical signs
Equine influenza virus causes clinical disease of the upper respiratory
tract. The virus spreads rapidly, and naïve or immunocompromised horses
are at higher risk of developing disease. Clinical signs include fever,
coughing, serous to mucopurulent nasal discharge, depression, muscle
soreness, anorexia, and enlarged regional lymph nodes. Colic (abdominal
pain) and edema of the legs and scrotum have also been observed with
influenza infection.
In the absence of secondary complications, healthy, adult horses
usually recover from EI within one to two weeks; however, coughing may
persist for a longer period. Young foals lacking adequate maternal
antibodies are at risk of developing a rapidly fatal viral pneumonia.
Recovery from EI is complicated and prolonged by the development of
secondary bacterial infections. Deaths have been reported as caused by
secondary bacterial pneumonia and pleuritis. Purpura hemorrhagica, a
potentially fatal, immune-mediated disease, has also developed
secondary to EI infection. Fatal interstitial myocarditis (inflammation
of the heart muscle) can occur during or after infection.
Diagnosis
A tentative diagnosis of EI is often made based on clinical signs.
Diagnosis can be confirmed by detection of the virus in samples from
nasal swabs. Traditionally, a diagnosis of EI was confirmed by
inoculating embryonated hen eggs with material from nasopharyngeal
swabs and subsequently isolating the virus. Alternatively, paired acute
and convalescent serum samples can be submitted for EI hemagglutinin
inhibition; a fourfold-or greater increase in antibody titer is
diagnostic for EI. Other diagnostic methods include reverse
transcriptase polymerase chain reaction (PCR) and nested reverse
transcriptase polymerase chain reaction. Reverse transcription PCR is
more rapid and sensitive than serologic testing, and more rapid and
specific than virus isolation.
Preferred samples for diagnostic testing are fresh nasopharyngeal swabs
that are shipped overnight at room temperature. If serologic testing is
desired, a minimum of 2 ml of whole blood should be collected in an
EDTA (lavender top) or ACD (yellow top) tube and shipped overnight at
room temperature.
Treatment
As for all viral disease, treatment is largely supportive. Good
husbandry and nutrition may assist horses in mounting an effective
immune response. Rest reduces viral shedding. Because tracheal
clearance rates (an indication of the ability of the respiratory tract
to eliminate particles, mucus, and infective organisms) are reduced for
up to one month after infection, rest is also recommended after
resolution of clinical signs. Antipyretics are recommended for horses
with fevers exceeding 105°F (40.5 C) and/or severe depression and
anorexia. Pneumonia in more severely affected horses responds best to a
combination of broad-spectrum bactericidal antibiotics and maintenance
of hydration via intravenous administration of fluids.
Currently available antiviral drugs are approved for use in humans only
and little is known about their use in equids. Often their cost
precludes their use. Veterinarians who use approved drugs in a manner
that is not in accord with approved label directions (e.g., use of an
antiviral drug only approved for use in humans) must follow the federal
extralabel drug use regulations of the Animal Medicinal Drug Use
Clarification Act (AMDUCA).
Morbidity and mortality
Morbidity associated with EI in naïve populations is estimated at 60 to
90%; to date, mortality of horses with confirmed infection has ranged
from 1% to 20%. Higher fatality rates are observed in foals,
malnourished or immunocompromised equids, and donkeys.
Prevention and control
Inactivated intramuscular and intranasal vaccines are commercially
available for prevention of influenza in equids. The American
Association of Equine Practitioners (AAEP) has produced Guidelines for
Infectious Disease Outbreaks; these guidelines state that the
administration of booster influenza vaccines to apparently healthy
animals in the face of an outbreak may be of value. For animals that
were unvaccinated prior to the outbreak, the use of a modified live
intranasal vaccine may be preferred because it can induce protective
immunity within 5 days. The Guidelines are available to AAEP members
through the AAEP website (www.aaep.org) or the AAEP office
(aaepoffice@aaep.org).
Vaccination is not always effective in preventing infection, but it
appears to reduce severity of clinical signs. The AAEP has produced
"Guidelines for Vaccination of Horses" that can be obtained by
contacting the AAEP at aaepoffice@aaep.org.
The EI virus is an enveloped virus that appears to be easily killed by
disinfectants in common use in veterinary facilities, such as
quaternary ammonium compounds and 10% bleach solutions. The most common
source of infection is the introduction of a new animal into the herd;
therefore, isolation of newly acquired animals is recommended.
Isolation protocols should be rigorously applied for horses showing
signs of respiratory disease, and should be maintained for 21 days
after the last horse has appeared to recover from the infection.
Clothing, equipment, surfaces, and hands should be cleaned and
disinfected after exposure to horses known or suspected to be infected.
This information has been prepared as a service by the American
Veterinary Medical Association. Redistribution is acceptable, but the
document's original content and format must be maintained, and its
source must be prominently identified.
Movement Restrictions
What restrictions have been put on horse movements in NSW?
All movements of horses in NSW have been restricted in an effort to
control the spread of equine influenza and to prevent it from becoming
established in Australia.
The New South Wales Department of Primary Industries is sending
Inspectors under the Stock Diseases Act 1923 to inspect horses where
there is concern that they may have been exposed to an infected horse.
Some horses, which were in transit when the restriction was put in place, were allowed to continue their journey.
What restrictions are on horse movements in other states?
It has been agreed that all states and territories will implement a
standstill on the movement of horses for at least the next 72 hours.
Horse transporters are requested to abide by the standstill and ensure
their vehicles and equipment are cleaned before any future use.
Animal health authorities recommend that all equine events and gatherings should not take place during this time.
Horse owners are being asked not to move horses from their properties
and that they keep informed about updates for further restrictions.
Avoid contact between your horses and other horses.
A number of race meetings have been called off in Australian states.
Agricultural Shows, Breed Shows and other horse events have also been
cancelled throughout NSW.
Racing clubs and other equine associations are being asked to cancel or postpone any meetings or events.
What happens if my horse is at an event?
Horses at events outside NSW can return directly home provided the
travel is only within the state where the event is being held.
Horse owners currently at events can return directly home after thorough cleaning of all their equipment.
Why are movements and events being restricted?
The primary spread of equine influenza is by contact between infected
horses. In order to ensure spread does not occur all horse movements
have been prohibited.
Please check for the latest information on movement restrictions at:
http://www.outbreak.gov.au/pests_diseases/pests_diseases_animals/equine_influenza/faqs.htm
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