Learn about the impact of infectious disease on sustainable animal-based food production by understanding the science of growth, immunity, and infection and by learning the problem-solving skills needed to advance animal health and food production through optimal management practices. There is a growing global need in agricultural production for a workforce that is capable of integrating knowledge of animal health and production with an understanding of consumer preferences in the context of economic reality, business efficiency, and ethical constraint. However, current evidence suggests that there is a growing shortage of people with the knowledge and problem-solving skills required to match the rapid advances being made in animal health, science, and food production. The results of this shortage are wide-ranging and could lead to challenges in food security and agricultural economic competitiveness in some countries. In this course we will explore the effect of infectious disease on sustainable animal-based food production. The content and learning outcomes of this new course will be designed to be relevant across different food production sectors (i.e., beef, dairy, poultry, and pigs). While the instructors will provide the participants with a strong scientific base for understanding the impact of infectious disease in animal-based food production, the emphasis of the material will be on practical problem-solving and will be directed towards equipping participants with a platform for developing the skills needed to contribute to sustainable food production.
6.5. Foreign Infectious Disease: The Enemy Without and the Control Within
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来自 University of Illinois at Urbana-Champaign 的课程
Sustainable Food Production Through Livestock Health Management
121 个评分
University of Illinois at Urbana-Champaign
121 个评分
从本节课中
Week 6: Infectious Disease and the World's Food
This week we will be discussing infectious disease and its impact on food safety and security at the regional, national, international, and global level. We will also help you understand how outbreaks of important infectious diseases, such as Ebola and foot-and-mouth disease, are tracked and investigated.
与讲师见面
Dr. Jim Lowe, DVM, MS, Dip ABVP (Food Animal)Associate Professor
Integrated Food Animal Management Systems, College of Veterinary Medicine
Dr. Brian Aldridge, BVSc, MS, PhD, Dip ACVIM (Large Animal), MRCVSClinical Professor
Integrated Food Animal Management Systems, College of Veterinary Medicine
[MUSIC]
My name's Gay Miller.
I'm a professor here in the College of Veterinary Medicine at the University of
Illinois and it's great for me to share with you some information about
national important infectious diseases.
In this particular time,
we're going to talk about a specific national important and infectious disease,
one that's a foreign animal disease, foot and mouth disease.
This disease, I'll just share with you a little bit about some of the basics of
foot and mouth disease.
It is a very highly infectious viral disease.
It is foreign to the US, meaning we don't have it here in this country currently and
we hope to never to have it in this country actually.
It is transmitted by a whole many different modes, right?
So it can be transmitted by semen,
it can be transmitted by direct contact with infected animals,
it can be transmitted by milk, by meat, a whole variety of ways.
It also is a virus that can be transmitted through the air.
So the virus can latch onto dust particles and
actually travel long distances, hundreds of miles, by air.
And small number of viral particles
actually are needed to infect any particular animal.
Just to share with you how important foot and mouth disease is,
it was the first animal viral disease ever discovered.
It was so important.
We were having outbreaks in this country and we really needed to figure
out what was causing this disease that caused vesicles to appear at
mucocutaneous junctions or around the mouth, around the ends of the teeth,
at the vulva where the inside of the body meets the outside of the body.
Vesicles form there and inside the mouth actually,
vesicles form and when they break, those tissues slough off, and
it causes lameness, really serious lameness, especially in hogs.
It affects all cloven hoofed animals.
So pigs, cattle, sheep, goats, camels,
wild deer, a lot of animals are affected by this virus.
It causes low mortality actually except in very young animals, but
it is a disease that is really feared because it has huge trade implications.
The minute that we would learn that we have foot and
mouth disease in this country, just like that our ability to
export any animal product that could potentially be infected would be gone.
And that's really important for us.
A big important activity for USDA is working to ensure that we
are able to trade our animal products with other countries and
if we had FMD, we couldn't do that.
We would have to announce to the world that we have foot and mouth disease and
the world would say, we're not taking your products.
And we would also say we're not sending you our products because we don't want
to be a responsible party in helping to transmit the disease in any fashion.
That's important for us because the US exports a lot of animal products.
Over a fourth of the pork produced in this country is exported product.
The value of that pork exceeds now $6 billion a year.
That value would be gone instantly, should we have an outbreak.
So the USDA, we work very hard to keep diseases like foot and
mouth disease and other highly infectious contagious diseases,
especially those that are foreign to the US, out of the US.
So they're not in our animal production streams.
So it is really important that producers recognize the symptoms and
signs of food and mouth disease.
So part of what I do is to be involved in educating producers in
this country what are the signs and symptoms.
And they are mainly any kind of the vesicular disease, so
things that cause vesicles in and around the around the areas where foot and
mouth disease affects the animal.
That should be an immediate red flag,
call your veterinarian if you see that kind of circumstance.
What a producer can do to decrease the likelihood that they would become
infected with disease like foot and mouth disease, first of all producers and
the bio-security that they have on their farms is really important.
So controlling the degree to which animals come on to the farm.
So animals that were not born and raised on that farm,
controlling that animal entry is really important.
Controlling the exit from the farm is also very important.
Basic hygiene associated with movement of people in and around farms, so putting on
clean coveralls when you're going to go out to be interacting with animals.
Putting on clean boots, not wearing your boots from your farm out into
the public and then coming back from being out to the public and
wearing those same boots or that same exterior clothing on to your farm.
All those things are really important but for a majority of producers,
they really don't have to worry about farm animal diseases on a day to day basis.
Those worries actually happen by and at USDA.
They are the place that is responsible for
keeping those diseases outside the United States.
So when we import live animals from all countries other than Mexico and
Canada where we do have trade that happens between Mexico and
Canada that is very free moving.
Actually we have a little more than
1 million cattle that move from Canada into the US per year.
Similarly about 1 million head of cattle move from Mexico into the US.
None of those animals move through quarantine.
Many move directly to slaughter but
not all of the animals move directly to slaughter.
In the case of hogs, more than 8 million head come into the US from Canada.
So that is one source or potential source for
a disease like foot and mouth to come into the US.
However, fortunately, Canada and Mexico have been free from foot and
mouth disease now since in the 1950s.
The US has been free from foot and mouth disease for almost a century.
And the other live animals that come into this country come in through very
specific ports and go into quarantine process.
They're tested for this disease, and
a whole variety of other foreign animal diseases,
to ensure that those that come into the United States and
are then moved out to farms or to zoos or
whatever they're going are actually healthy animals.
[MUSIC]
Many countries that have been free from foot and mouth disease for
varying lengths of time in the last, say since 2000,
have had major outbreaks of foot and mouth disease.
So the biggest and most classical example actually was the outbreak
that happened in 2001 and 2002 in the United Kingdom.
And there they had a massive outbreak.
It happened because it was not detected early on.
It started out in a species, sheep, where the symptom and
signs of the disease were not as prominent as they are in either cattle or in pigs.
And so it was hidden for a period of time and
actually moving around in the animal populations.
The UK, interestingly, chose to depopulate their way out of that infection,
which meant that they went in to farms which were suspected.
If they were found to be positive, all of the animals that were on that farm
that could have got foot and mouth disease, they were depopulated and
they were burnt or buried as the means by which then to dispose off the animals.
Because just because the animals is no longer alive doesn't mean that
it can't transmit the disease.
Actually, the virus can live inside the bone marrow,
and live inside meat, and so we also control trade that we
have with infected countries, where we do not accept
imports from countries that have foot and mouth disease.
In contrast, as an example,
there was an outbreak roughly about the same time in Uruguay and
their response was not to attempt eradication through depopulation.
But they chose to vaccinate to handle the outbreak.
And as a result they depopulated only about 6,000 animals compared to the UK,
more than 6 million animals were depopulated.
The size of the outbreaks were roughly the same, the length of time that
the outbreak was actively on-going was actually less in Uruguay.
So vaccination is becoming more and more a prominent component
that countries can institute in order to respond to this disease.
Let's compare and contrast the UK and
Uruguay's situation where the UK was depopulating and Uruguay was vaccinating.
If we were going to try to depopulate our way out of a FMD outbreak in
the United States, we might be able to do it depending on
where the outbreak occurred and the number of animals that were affected,
the species that were involved, and the size of the operations.
We have feedlots in the United States with 50,000 head and
more of animals that are on those premises at any point in time.
The ability to depopulate such a premises and then handle disposal and
decontamination from those premises is really, really challenging.
Much better would be a vaccination response.
In fact, some of the research has said it's almost impossible that we
could depopulate, should we have an outbreak, which would affect cattle, for
example, in the panhandle of Texas or in the heart of Kansas, which are two of
the most heavily, densely populated livestock regions in the United States.
The USDA has a bank of vaccine called the National Veterinary Stockpile.
And when we talk about vaccine banks,
somehow that makes it seem like we have a lot, right?
You make deposits in the bank, you can go take them out.
Well, you can only take out of the bank what you put in, and
it's extremely costly to put into the bank vaccines for foot and mouth disease.
First of all, the vaccine itself is not inexpensive, but
we have extremely large populations of animals in the US that we would want to
vaccinate should we have an outbreak.
So round numbers, roughly 60 million head of hogs on the ground at
any point in time in the US, approaching 100 million cattle.
Everybody who's involved in those kinds of industries would like to have vaccine,
and foot and mouth disease is not a simple disease.
So there are seven different serotypes for foot and mouth disease and
several sub-types.
So the World Reference Laboratory in Great Britain recommends banking
more than 20 different serotypes as a means by which to protect your country.
Now it's been almost 100 years since we've had an outbreak here.
So think about the cost associated with banking the number
of vaccines we would need for all of the different
potential strains that we might be, unfortunately,
getting into the United States and the cost is just phenomenal.
So we have developed limited banks that we hope will be used strategically in ways
that will help us fight this outbreak, should we have an outbreak of foot and
mouth disease, or this disease should we have an outbreak.
But we need to improve on that bank.
And part of what USDA would like is to get better buy-in, have better funding,
in order for them to be able to use vaccine as a component,
a realistically important component, should we have an outbreak of FMD.
So there are many elements that make this a truly wicked
problem to figure out how to appropriately respond.
First of all, not all vaccines are what we call DIVA compatible; the ability
to differentiate infected from vaccinated animals, D-I-V-A.
And vaccination does not prevent infection, okay?
And it is also possible that a vaccinated animal could retain
the virus inside their body.
Now there's no evidence that such an animal which has retained the virus
is actually an important individual to transmit the disease subsequently.
Still, subsequent testing would suggest that we still had the virus
inside the United States, so it makes it really complicated.
Also there's an organization called the OIE,
almost all countries in the world belong to the OIE.
And the OIE gives guidance about how to regulate or
determine appropriate trade that occurs between countries.
The goal is of course to improve animal health and
limit transmission of the disease in these kinds of things.
So they put out guidance which eventually sort of on
some level becomes regulation based on the way
many countries go about using those guidances.
And the amount of time that you're out of the ability to export
product depends in part on whether or not you're vaccinating.
So if you depopulate your way out of an outbreak,
you can return to export markets as being FMD free relatively quickly,
three months after the last known case, and with no evidence of transmission.
And of course, during that time, you're doing all kinds of testing, right,
to prove that you don't have the disease here.
But as soon as you incorporate vaccination as a component to your strategy,
in combination with depopulation, you increase the amount of time
that you are now out of the official FMD free market.
And many countries don't want to trade with you if you're actually vaccinating.
In fact the US, we don't trade with countries in the same way that
are vaccinating for FMD, even if they've been free of FMD for years.
And they're vaccinating because they're worried about the possibility of
importation or transmission from a neighboring country where they are.
So there are lots of complications associated with what is the right and
appropriate response for
how to manage during an outbreak of a disease like foot and mouth disease.
So we've used FMD here just to reflect a highly contagious viral disease and
how we would go about responding to it.
There are lots of diseases out there, lots of viral,
highly infectious viral diseases.
FMD is just one of many that are foreign.
And of course, we have many viral diseases inside the US also, and
so the bio security then and the approaches for internal infectious
diseases becomes a little bit different because we know we have it.
So what you are looking for is known and different, and
there may be strategies that are in place in farms that will limit introduction
because they test specifically for diseases that they know exist,
that they're trying to exclude from their farms.
And they test specifically to prove that they're negative,
if they're exporting semen, as an example.
So biosecurity on farm is really important to help in the prevention of
foreign animal diseases, of infectious diseases generally,
and give our animal populations an opportunity to be healthy,
to produce healthy food for consumers in the United States.
[MUSIC]
