THE FOOT & MOUTH DISEASE THREAT TO AMERICA: A R=
by Dr. Jack Woodall
American Reporter Correspondent
Rio de Janeiro, Brazil
RIO DE JANEIRO -- [Editor's Note: The author, founder of the acclaimed = ProMED-mail tropical disease mailing list, may well be the world's foremost=
expert on disease epidemiology and containment. His citations can be read = below or at http://www.promedmail.org. Responses to his proposal follow th= is article on the AR home page.]
It has previously been suggested that, in the event of the arrival of f= oot and mouth disease (FMD) in the United States, vaccination will be point= less since vaccine stocks are inadequate to provide any kind of barrier, an= d would best be used to protect breeding stock. [see: Foot & mouth disea= se - EU: use of vaccination (03) 20010329.0636].(1)
It was also argued that mass culling would not be the way to go --select= ive culling could be instituted, but at a projected cost to the economy of = $8000 per head for cattle, or $8 billion for each million head sacrificed, = the point of unbearable financial pain would soon be reached [see: Foot = & mouth disease, mass culling issue - U.S.A 20010404.0673].(2)
A further complication would be that farmers would undoubtedly slap rest= raining orders on the United States Dept. of Agriculture (U.S.DA) to postpone= both vaccination and culling, wrecking the whole exercise.
And although experience in other countries has shown that the logistic= s of culling are best handled by the military, the American public could we= ll object to daily tv coverage of the National Guard slaughtering healthy l= ivestock by the hundreds of thousands, and the smoke from the pyres rising = all over rural America, polluting the air and water.
So if vaccination is out, and culling will be hindered until it's too la= te to be effective, what's the solution? Consider the following scenario= :
Many different conditions apart from FMD can produce blisters on the = mouths and feet of livestock, but in a climate of apprehension the smart fa= rmer will, at the first sign of a suspicious lesion, sell the affected beas= ts. When a responsible vet gets to see a genuine case, the implications wi= ll be so grave that U.S.DA confirmation will be required before the official = announcement.
This might take a week -- time for two cycles of viral replication, an= d for the farmer and his neighbors to sell before a movement ban is slapped= on them. The stock will be in Texas in 24 hours. No 3km or 10km or any r= adius cull of adjoining farms will then be of the slightest use.
At the official confirmation of the first case of FMD, Japan and South= Korea, which between them buy 60 percent of all U.S. beef exports, will sl= ap a ban on U.S. beef and pork. Other countries will follow suit. Beef pri= ces will fall, beef futures will fall, rapidly followed by pork belly futur= es, since pigs can also be infected.
A state-wide ban on livestock movement will be impossible to enforce, si= nce U.S. cattle do not carry individual IDs and passports like United Kingd= om cattle, and state borders are wide open. The disease will run out of con= trol much faster than it did in the UK.
Proponents of mass culling will object that stamping out did succeed in = eradicating FMD outbreaks in Italy in 1993 and in Greece in 1994 and 1996 -= - and maybe in France this year (but the chance for re-infection in France = remains).
But those countries have nothing like the livestock population size an= d speed of movement that the United States has.
It takes about six months of disinfection before a culled farm is read= y for restocking, but if cases are still occurring elsewhere which result i= n a movement ban in the area, it will not be possible to restock at that ti= me, and the farmer may lose an entire breeding cycle.
How is he supposed to survive financially in those circumstances?
Vaccination proponents will say that vaccination worked for years in Eur= ope until it was banned there in 1990-91. But there is not enough vaccine = available in the world to do any good in the U.S. context. Plus, for the U= nited States to obtain FMD-free status, all vaccinated livestock will event= ually have to be destroyed.
So what does this all boil down to? The United States will just have t= o give up its FMD-free status, join the ranks of other big meat-producing c= ountries that have lost theirs, such as Argentina, Uruguay and Brazil(parti= ally), and accept the reduction in productivity of flocks and herds caused = by FMD infection.
Australia and New Zealand will not be able to make up the shortfall in= FMD-free beef on the international market, and exports of U.S. beef will s= lowly rise again.
The financial pain will be uncomfortable, but not nearly as severe as = if several million head of livestock had to be slaughtered and disposed of.= Somebody should run the numbers and confirm this.
What will happen, of course, in real life is that the U.S. will repeat a= ll the mistakes made in the UK in dealing with the current outbreak there. = It will be too slow to implement the first cull, too slow to enforce movem= ent restrictions, offer disincentive levels of pay to veterinarians and of = compensation to the farmers, and still be wasting time talking about vaccin= ation 10 weeks after the first recognized case occurred.
Politically, i= t probably has to develop like that.
But in the end, as the legal challenges multiply and the economy begin= s to falter, it will be recognized that the most cost-beneficial solution w= ill be to let the epidemic run its natural course. ----------------------------------------------------
So now let's hear the arguments against this radical proposal.
??? ? ?= ???? ??? ???i>The two ProMED-mail posts below appear in the order they are= cited above:
(1) Vaccination? Not for the U.S.A, but perhaps for Europe
[The] current policy of APHIS [U.S. Department of Agriculture's Animal & P= lant Health Inspection Service] is that FMD vaccine will only be used in th= e U.S.A under 5 circumstances: if an outbreak has not been contained within 6= months, if it affects 25% of the livestock in a given area, if the cost/be= nefit ratio of slaughter approaches 1:2, if the disease becomes endemic in = the wildlife of 3 or more states, or if slaughter is found to be illegal.
Of course, as is happening in Europe, the policy on vaccination could ch= ange in the face of a crisis. But it will be a complete waste of time to ar= gue the pros and cons of vaccinating in the U.S.A when the disease reaches th= ere -=AD the word "when" is used deliberately -- for the following reasons.=
The U.S. stockpile contains 2.5 million doses of type O vaccine, the type = that is causing the current pandemic. But there are 8 million head of cattl= e in Texas alone, not to mention sheep and pigs. Given the massive daily mo= vements of livestock in the U.S.A, and the time needed to vaccinate 2.5 milli= on head, it would just be a diversion of scarce resources to attempt vaccin= ation there.
Even ring vaccination around outbreaks would be useless. The British exp= erience has shown that, by the time a new outbreak is detected, the disease= has already spread far beyond that locality. And vaccination of a strip al= ong the Mexican or Canadian border would not help. Cattle are no longer her= ded from one country to another; one truck crosses those borders every few = seconds, and does not stop until it is far inside the U.S.A.
The kindest thing would be for the U.S. to give its vaccine stock back to = Europe, where it came from, to help the crisis there, and concentrate on ot= her means of control when the pandemic arrives. Alternatively, the vaccine = could be given now to protect U.S. breeding stock or rare breeds there which = are not going to enter the food chain.
APHIS. Foot and mouth disease emergency disease guidelines. Washington D= C: Animal Plant Health Inspection Service, U.S. Dept of Agriculture, October= 1991.
Salt J. Vaccination against FMD. Veterinary Vaccinology, Elsevier = Press, 1997. pp.641-9.
Callis JJ. Problems of vaccine distribution (vacc= ine banks). Veterinary Vaccinology, Elsevier Press, 1997. pp.703-4.
(2) Mass culling? Not for the U.S.A
A previous post on ProMED-mail (reference above) discussed why vaccinati= on is out of the question for controlling a future FMD outbreak in the U.S.A;= it could be used for protecting breeding stock. This contribution discusse= s why mass culling -- as opposed to selective culling -- although being use= d in the UK, is also out of the question for the U.S.A.
There are several arguments against mass culling, which taken together a= dd up to making it an impossible task for a country with the density of liv= estock the U.S.A has in many states. First, it kills many adult animals which= would otherwise have survived infection, albeit with perhaps a 10 percent = loss in productivity (as compared with a 100 percent loss if they were kill= ed). That leaves a legacy of surviving but infectious animals, which would = take perhaps years to eliminate in order for the U.S.A to return to FMD-free = status.
But since Japan & South Korea, which together account for over 60 percen= t of U.S. beef & pork exports, will ban imports of both from the U.S. at the fi= rst report of an outbreak (Australia and New Zealand will be only too glad = to fill the gap), a 10 percent loss in meat production would not affect the= capacity to export to other markets.
Second, the logistics of slaughtering and disposal of possibly millions = of head of livestock quickly overwhelms capacity. During the FMD outbreak i= n Taiwan in 1997, 4 million pigs were culled, at a peak rate of 130 000 per= day, after the army got up to speed. Let's say the U.S. Army could do the = same on the larger U.S. feed lots. That's still 30 days to kill 4 million; = 30 days in which the disease is still spreading. It is questionable, howeve= r, whether the public would stand for the TV spectacle of the U.S. Army or Na= tional Guard shooting livestock. Even the UK has not yet gone that far.
Third, the risk of delays due to litigation are great. Farmers and natio= nal associations of breeders would seek injunctions, animal rights and envi= ronmental groups would do the same. Slaughtering could be held up for weeks= . Also, the huge amounts of money needed to finance a big emergency would= exceed existing provisions and require additional legislation, preceded by= much debate, before being approved. Even emergency funds from the White Ho= use would take time to arrive.
My experience with public health authorities has shown that they will al= ways live in hope that the outbreak will be contained with minimum expendit= ure, leading inevitably to too little funding too late to do any good. I ha= ve no reason to believe animal health authorities will react differently.
Models exist that purport to show for U.S. conditions under the most optim= istic circumstances, if culling of 95 percent of latently infected plus inf= ectious herds can be achieved beginning in the second week after recognitio= n of the first outbreak, "only" 20 percent of an affected region's herds = need be destroyed to achieve control. But if culling to that level is delay= ed by just one week, the eventual destruction will have to be more than 90 = percent. I don't think anyone can seriously believe any state agency is g= oing to be able to move that fast, or be able to cull to that level.
Fina= lly, a recent analysis of the potential cost of FMD in California projects = direct costs, plus production losses, plus trade losses would sum to around= U.S.$8000 per head culled, or U.S.$ 8 billion per million head -- and this may= be a conservative estimate. Twenty percent of the cattle in Texas alone is= 1.6 million head.
I rest my case.
Ekboir J 1999. Potential impact of Foot and Mouth Disease in Californ= ia. Agricultural Issues Center, Div Ag & Nat Res, Univ. Cal. Davis.
Woodall J 2001. Vaccination? Not for the U.S.A. In Foot & mouth dis=
ease - EU: use of vaccination (03), ProMED-mail archive no.20010329.0636&p_=
year=3D&p_month=3D">20010329.0636&p_year=3D&p_month=3D">20010329.0636 29 Ma=
r Yang PC, Chu RM, Chung WB, Sung HT 1999. Epidemiological characterist=
ics and financial costs of the 1997 Foot and Mouth Disease epidemic in Taiw=
an. Vet Rec 145 (25): 731-734. End Citations
Dr. Jack Woodall heads the Nucleus for Investigating Emerging Infectious=
Diseases, Dept. of Medical Biochemistry, Institute of Biomedical Sciencesat=
Federal University in Rio de Janeiro, Brazil. He is the former Moderator a=
nd founder of ProMED. Reach him at firstname.lastname@example.org
Yang PC, Chu RM, Chung WB, Sung HT 1999. Epidemiological characterist= ics and financial costs of the 1997 Foot and Mouth Disease epidemic in Taiw= an. Vet Rec 145 (25): 731-734.
Dr. Jack Woodall heads the Nucleus for Investigating Emerging Infectious= Diseases, Dept. of Medical Biochemistry, Institute of Biomedical Sciencesat= Federal University in Rio de Janeiro, Brazil. He is the former Moderator a= nd founder of ProMED. Reach him at email@example.com