Dutch to push “vaccination for life” ––may end culls of healthy livestock

From ANIMAL PEOPLE,  July-August 2013:

DEN HAAG––Dutch state secretary of economic affairs Sharon A.M. Dijksma on June 4,  2013 committed The Netherlands to trying to reverse European Union and other international policies which require culling livestock who have been exposed to contagious diseases of concern,  even if the animals are apparently healthy and have been vaccinated against the feared diseases.

If the  Dijksma initiative succeeds,  it will mean globally that about a million fewer pigs and cattle per year will be raised and killed each year to achieve the same levels of production,  because a million a year will not be just culled and burned or buried.

Called “Vaccination for Life,”  the initiative has implications for intercontinental trade in live animals (see sidebar).  But by far the greatest number of animals affected by the present EU and parallel international policies  are raised for domestic dairy and egg production,  or local slaughter,  which within the EU often means the animals are trucked across a national border only a relatively short drive away.  Dutch-raised pigs and poultry,  for example,  are often slaughtered in Germany.

[pullquote]Poll and 10 other veterinarians in October 2001 asked the Royal Dutch Veterinary Association to endorse a warning to the Dutch government that they would go on strike rather than ever again kill animals who had already been vaccinated.  [/pullquote]

Only the milk,  eggs,  or meat of most of the animals raised within the EU––and especially the Netherlands––travel long distances.  

But if the animals have potentially been exposed to any of a long list of infectious diseases,  or have been vaccinated to stop disease oubreaks,  under the present trade rules no product or byproduct of the animals may be exported in any form. 

As many as two billion poultry and an average of more than a million hooved mammals per year worldwide have been culled during the more than two decades that the EU has prohibited imports and exports of vaccinated animals,  animal products,  and animal byproducts, including  milk,  meat,  eggs,  and leather.  

The culling has become so routine that the cost of culling,  other than in very large cases,  is amortized into the ordinary animal industry costs of doing business.  

EU requirements meanwhile have become the default global standard governing movements of animals who are deemed to have either been potentially infected or vaccinated.  

The present culling requirement covers all animals whose products and/or byproducts may be exported,  not just animals who may be exported alive animals,  because pathogens often travel with products and byproducts––even minute particles that are moved accidentally.  

Recent anthrax outbreaks have been traced to spores beaten out of leather drums that in some instances were decades old.  

Exotic Newcastle disease, a fungal infection that sporadically kills tens of thousands of poultry raised in close confinement,  is often traced to workers’ contaminated clothing.  (Usually the workers have been involved in cockfighting,  pigeon-racing,  or other activities that involve handling birds outside of the poultry barns.)  

Widespread prohibiton of imports of products and byproducts from vaccinated animals have often caused the governments of nations that export livestock products and byproducts to simply cull potentially infected animals by any means available,  hopng to end the outbreaks by culling alone,  without investing in vaccination.  

The economic calculation in such instances is that vaccination and culling require about the same amount of time spent per animal to accomplish,  but vaccination costs veterinary time,  while culling can be done by low-paid farm workers or soldiers.

The South Korean Ministry of Food, Agriculture,  Forestry & Fisheries therefore culled more than 1.7 million pigs,  cattle,  and dogs (believed to be mostly dogs raised for meat) during a two-month foot-and-mouth disease outbreak in 2010-2011.  

Most of the pigs were buried alive.  Eventually 1.2 million cattle and 210,000 brood sows were vaccinated to end the outbreak,  but only after weeks of appeals from international disease control experts and public protests led by the organization Korean Animal Rights Advocacy.

“DIVA” vaccines

Dijksma’s policy pronouncement applies immediately to animals vaccinated against foot-and-mouth disease and classical swine fever.  

“I shall take my ministerial respons-ibility as far as anchoring this policy in law,  stimulating research,  and creating acceptance for emergency vaccination,”  Dijksma pledged.  Agribusiness “will have to meet their own responsibility for the actual development and production of vaccines and for the marketing and sale of vaccinated animals and their products,”  Dijksma said.

Dijksma issued her statement in response to questions raised by Dutch legislators in March 2013.  Dijksma prefaced a lengthy written review of vaccination and culling policy by outlining the difference between preventive vaccination against viral disease and emergency vaccination,  introduced as a crisis response during a disease outbreak.   

Preventive vaccination,  Dijksma explained,  is exemplified by the standard vaccinations against common diseases that most children receive in early childhood.  Because of the current international trade rules,  preventive vaccination is not widely used in animal agriculture.

Like preventive vaccination,  emer-gency vaccination stops the spread of a viral disease.  But emergency vaccination is used only to help contain and eradicate disease outbreaks that are already underway.

A third type of vaccination,  post-exposure vaccination,  is used to immunize humans who have been bitten by dogs suspected of being rabid.  This type of vaccination is not used in animal agriculture at all.

The conventional vaccines used in either preventive or emergency vaccination do not always produce immune responses in vaccinated animals––and humans—that can easily be distinguished from actual exposure to a contagious viral disease.  

In addition,  though vaccine failure is now relatively rare,  mistakes in vaccine production and improper vaccine storage have sometimes resulted in emergency vaccination helping to spread the diseases that the vaccination was meant to stop.

These issues have recently been overcome by the introduction of so-called DIVA vaccines.  “DIVA” is short for “differentiating infected from vaccinated animals.”  DIVA vaccines are created by engineering them to produce antibodies with slightly different “disease signatures” from antibodies to the actual diseases that the antibodies are designed to fight.

“After emergency vaccination has been applied,  two alternatives are possible:  either you then destroy the vaccinated animals,  or you do not.  The latter approach is called vaccination ‘for life,’  and is the option that I prefer,”  Dijksma said.

Global influence

The change in Dutch policy announced by Dijksma will have immediate international repercussions.  Occupying less than one-thousandth of the world’s surface,  The Netherlands nonetheless ranks third among nations in exports of livestock and meat products––and is first in exports of live pigs and chickens,  though most travel shorter distances to slaughter in Germany than the majority of pigs and chickens who are raised and slaughtered within the U.S. and Canada.  

The De Peel region of The Nether-lands,  near the German border,  reportedly has more pigs per acre than anywhere else in the world. The Netherlands is also a longtime global leader in intensive confinement rearing of dairy cattle,  goats,  and poultry.

Encouraged by mid-20th century progress in using vaccination to eradicate rinderpest,  an initiative begun in The Nether-lands,  the United Nations Food & Agricultural Organization,  World Organization for Animal Health,  EU,  and European national veterinary authorities have in recent decades promoted the development and use of vaccination against other livestock diseases.

“European cattle were successfully preventively vaccinated against various contagious diseases for many years,”  summarized Dijksma. But after most of the best-recognized contagious viral diseases were eliminated from European livestock,   “Vaccination to maintain animal immunity was no longer outweighed by the advantages.  Vaccination is costly,  and impedes export to nations that are worried about the spread of infectious diseases from vaccinating countries to their own,”  Dijksma acknowledged,  “because until recently there was no way to tell whether an animal had been vaccinated or was infected.”

Foot-&-mouth

Foot-and-mouth disease may be the most prominent of the many diseases covered by policies against importing or exporting vaccinated animals.  Far more animals have been culled in response to the H5N1 avian flu virus than in response to all other disease outbreaks combined, but foot-and-mouth disease has led to culling the most mammals.

Explained Program for Monitor-ing Emerging Diseases moderator Arnon Shim-shony,  of the Koret School of Veterinary Medicine at Hebrew University in Jerusalem,  “Until 1991 mass vaccinations against foot-and-mouth disease were annually applied in EU member countries including Germany,  France,  the Netherlands,  Belgium,  Spain,  and Italy,  with satisfactory results.  Under pressure of nations including the United Kingdom,  Denmark, and Ireland,  this was discontinued.  Imports of vaccinated animals and their products into the EU were banned. Some traumatic experiences since––in particular,  the 2001 foot-and-mouth disease epizootic in the United Kingdom and some continental EU countries––contributed to significant changes in public opinion regarding the non-vaccination,  stamping-out policy.”

The 2001 foot-and-mouth disease strain reached Britain after hitting at least 25 other nations,  beginning in 1990,  when it was identified in northern India.  The Pan-Asian strain,  as it was called, surged across India with the illegal traffic in cattle for slaughter in the southern state of Kerala,  then east,  reaching Taiwan by 1999.  It spread west into Saudi Arabia,  Turkey,  and eastern Europe in waves coinciding with the annual haj pilgrimage to Mecca (as detailed in “Epidemic of Faith,”  ANIMAL PEOPLE,   April 2001).  

Eventually,  after exploring the theory that the Pan-Asia foot-and-mouth strain reached Britain via food waste from a freight ship,  many British and American scientists concluded that it more likely reached Britain on the wind,  after a sandstorm swept northern Africa in mid-February 2001.  Satellite photos showed that dust from one of the hardest-hit areas in north Africa settled in Britain seven days later––seven days before the outbreak was identified in Britain.

Double decimation

Foot-and-mouth disease was eradicated from Britain by the end of 2001,  for at least the third time in 80 years,  by killing every hooved animal on 9,677 farms,  including 4.9 million sheep,  763,787 cattle,  and 428,000 pigs.  

Underscoring the magnitude of the slaughter,   the Latin word “decimation” literally means killing one animal or human in ten.  The British cull of hooved lifestock was one in six:  nearly double decimation.  

Britain had only just completed culling 3.5 million cattle,  over 15 years,  to stop the spread of mad cow disease.  Believing that effort to have been successful,  albeit against a much less contagious disease transmission agent,  British authorities rejected the use of vaccination to contain the Pan Asian foot-and-mouth disease outbreak,  because vaccinated animals as well as diseased animals were,  and are,  banned from European commerce.   Rejecting vaccination proved to be a mistake.  A vaccination strategy would have ringed infected herds with immune animals before culling began,  thereby keeping foot-and-mouth disease from spreading on the wind,  on the clothing of workers,  or in any other accidental manner.  Culling alone did not prevent extensive accidental transmission of Pan Asian foot-and-mouth disease to all parts of Britain before the outbreak was quelled.

Dutch vets revolt

The hoof-and-mouth epidemic hit The Netherlands about a month after reaching Britain.  Retired small-animal veterinarian Peter Poll, then 68,  was recalled from retirement to help direct a vaccination-and-slaughter campaign that eradicated the Dutch outbreak within just two weeks,  at cost of  only  265,000 animals killed.  

Despite the nominal success of the effort,  especially compared to the British catastrophe,  Poll was appalled by the cost in lives, amounting to 10,000 animals killed for every case of hoof-and-mouth disease actually detected.  Poll and 10 other veterinarians in October 2001 asked the Royal Dutch Veterinary Association to endorse a warning to the Dutch government that they would go on strike rather than ever again kill animals who had already been vaccinated.  

They asked for repeal of the European Union requirement that animals vaccinated against hoof-and-mouth be killed before livestock from that nation can be exported.

This was the beginning of the long reconsideration of Dutch policy that Dijksma formalized on June 4,  2013. “Back in 1991,”  when the European Union instituted the present policy,  “we assumed that biological security measures at the outer borders of the EU would be a sufficient barrier to prevent the return of infectious animal diseases,  and that  if there were any new outbreaks despite this barrier,  they could be dealt with quickly and ‘disease free’ status could be quickly restored,”  Dijksma said.  “To this end, European Union member states were required to destroy all the animals on any farm where one or more infected animals were discovered, and to ban the transport of any and all animals within a certain safety zone around such a farm.

“The European non-vaccination policy was and is advantageous for the Dutch export of animals and animal products,”  Dijksma admitted. “However,  discontinuing preventive vaccination and the disappearance of animals carrying antibodies” to the diseases formerly vaccinated against “has also made our stock of cattle vulnerable to these diseases again.”  

Dijksma mentioned,  in addition to the 2001 outbreak of foot-and-mouth disease,   a 1997 outbreak of classical swine fever in The Netherlands that led to the slaughter of 1.1 million pigs and piglets at 39 Dutch farms.  “The only legally allowed way to prevent the spread of these outbreaks was the mass destruction of healthy animals on uninfected farms surrounding any infected farm,”  Dijksma said.  “Because of widespread public indignation about the mass destruction of healthy, uninfected animals,  the Netherlands and the EU are now discussing adjustment of the non-vaccination policy.  Development of DIVA vaccines has played an important role in this discussion.” 

Positive response

Already,  Dijksma said,  “Dutch efforts have been partly responsible for a policy change that allows emergency vaccination in Europe in the cases of classical swine fever,  foot-and-mouth disease,  and avian influenza.  This is a relaxation of the former strict non-vaccination policy, but it is still restricted by very specific terms and conditions intended to minimize the risk of spreading of these diseases.” 

Beyond the present EU prohibition of preventive vaccination,  Dijksma mentioned complications  including “the existence of multiple virus types of foot-and-mouth disease and avian influenza;  the cost of yearly vaccinations;  and the effect of repetitive vaccination on animal welfare. A final question,”  Dijksma finished,  “is whether preventive vaccination is desirable in light of how important livestock exports are for the Dutch economy.”

While “The Dutch government and the meat industry together have decided to push for the use of emergency vaccination when classic swine fever and foot-and-mouth disease occur,  it is difficult to predict how the international community,  especially outside the EU,  will react if  The Netherlands ever does actually respond to an outbreak with emergency vaccination,” Dijksma said.

“The reactions of other EU member states indicate clearly that opinion about emergency vaccination is changing in the right direction,” Dijksma said.  “Germany recently laid down a rule that the option of emergency vaccination must be explored before mass destruction of animals may take place,  in the case of diseases for which a vaccine exists.  The Animal Health Quadrilateral Group,  consisting of the U.S., Canada,  Australia and New Zealand,  has also embraced the strategy of emergency vaccination ‘for life.’” 

––Merritt Clifton (with document translation help from Alexandra Semyonova)

 

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