Mr.
National
Manager
Agriculture
Security and Animal Health
Ministry of
Agriculture and Fisheries
Wellington
N E W Z E A L A N D
-------------------------------------
Dear Dr
MacDiarmid,
thank you very much for your interesting
letter of
First, few words on your statement
"If, for a particular trade, we have available reducing tools (tests,
treatment, whatever ) which will reduce the risk by 10,000 or 100,000 times,
what does it matter what the starting risk was ?" Risk reduction measures can be sufficiently
effective in case of products to be processed destroying eventual pathogens -
disinfected or sterilized. However, this is not the case when importing animals
and crude products where we depend a lot on reported situation and test
results. These results are almost never reliable for 100 % depending on
specificity and sensitivity of the methods used, range and frequency of
investigations, interpretation of the results as well as on investigators
professional level. Sometimes human errors cannot be avoided. Negative
diagnostic test results not always correspond with the reality (referring also
to your methods based on starting risk described in Rev. sci. tech. int. Epiz.,
1993, 12, p. 1093-1107).
The problem is usually multi-etiological
risk and not only mono-etiological one. I agree that the priority have the
diseases of the OIE list A. But internationally reported are about 150
diseases. Several hundreds of not controlled but important diseases (including
many zoonoses) spread also through export/import of animals and their crude
products without any protective measures (specific import conditions) and risk
reduction procedure.
Importing country needs to import healthy
animals and innocuous products and not to be depended on risk reducing measures
only without considering starting risk. Majority of reducing procedures are
usually not for 100 % reliable and cost money, time and material. It is preferable
to import under zero-risk or under minimal possible starting risk. The concept of OIE International Animal
Health Code is based correctly on defining conditions for zero or minimal
starting risk in List A and B disease.
We cannot under-estimate veterinary services
evaluation. For example see Guidelines for the evaluation of Veterinary
Services "as an important element in risk assessment process"
(Ref.: Rev.sci.tech.Off.int.Epiz., 1993, 12(4), 1291-1313).
There are many examples that in
spite of mathematical risk assessment, all the risk reducing measures and
perfect veterinary certification many specific diseases were spread through animal commodities to
other countries including specific diseases free ones or where these diseases
have (not easily) been eradicated. The
losses caused by introduced disease can be enormous and usually not covered
(paid) by exporting country.
a) Bovine spongiform encephalopathy spread by
import from U.K. to Republic of Ireland, Falkland Islands, Portugal, France,
Denmark, Switzerland, Oman etc. BSE belongs among so called "new emerging
diseases" not yet well known and controlled. BSE in
b) Hog cholera introduced by import of pigs and
pork products:
c) Eradication of screwworm (Cochliomyia
hominivorax) introduced to
You can see that in spite of all risk reducing
measures we could not avoid the introduction of these pathogens by so called
"save" import.
There are many example of spreading of
"imported diseases" from primary outbreaks creating many
secondary ones requiring costly and demanding eradication measures. Examples:
Ratios primary/secondary foot-and-mouth outbreaks in EEC country in years
1977-1987:
I
remember that in 1981, when I was Chief-editor of the FAO-OIE-WHO Animal Health
Yearbook, Lesotho government instead of returning the questionnaire reported by
cable that no animal diseases exist in the country. That time
This is once more a reason for giving
priority to zero or minimum starting risk in exporting countries and so try to
prevent disease introduction and avoid serious negative consequences requiring
also expenses to be covered by government budget (paid by the country tax
payers).
As I mentioned in my previous letter, there
is a substantial difference of the risk between the import of animate and
inanimate commodities. Circulation of etiological agents and transmissibility
of infectious animal diseases is often very complex, not always well known,
difficult to control and is very different according to individual animal species
and their specific products as well as according to particular external
conditions. The most dangerous are the animals - asymptomatic carriers of
specific pathogens.
I am a bit afraid that veterinary conditions
for international trade in animals and their products can be sometimes abused
in "trade war". I feel the consequences of so called "new trade
international policy" also in the fact that for the first time a lot of
countries did not return the usual annual questionnaire for international
animal health/disease information system: In FAO-OIE-WHO Animal Health Yearbook
1994 73 countries (not only developing ones) are missing , i.e. one third of
world ! Lack of international epizootiological information can easily
contribute to open the door to inter-country spreading of animal diseases.
I would like to stress once again that every
case is different depending on many aspects. It cannot be used one fixed
model for all the types of export/import commodities and for all circumstances,
conditions and needs. According to my opinion, when assessing disease
introduction risk, beside biological scientific aspects, also type, purpose,
distribution and use of the commodity, credibility of exporting country
as well as previous experience with it should be considered. Priority must be
given to maximum possible protection of specific diseases free populations and
territories.
We must be very and very cautious when
assessing the disease risk for import decisions ! We have to try as much as
possible to find solutions acceptable not only for traders but first of all for
specific diseases free country (territory) protection. This is also our
responsibility toward importing country farmers, consumers and economy.
The main criterion of all theory,
including risk assessment methods and interpretation, is the practical impact
and final result ! The number of new cases of spreading diseases through
the export of animals and their products is increasing due to disease risk
under-estimation . On the other hand, the number of cases when the
countries report success story of eradication of these diseases is very
sporadic and decreasing ! The result is that the animal population health
situation in the world is getting worse and thus in the future their
control and eradication will be much more difficult and very costly, if
feasible at all. Not speaking about negative economic impact and public health
consequences of spreading zoonoses. This fact is not of interest for
international businessmen who call for maximum benevolence in defining
veterinary import conditions. However, veterinary services and international
organizations must concern about this risky situation.
Mathematical analysis itself cannot replace
a complex analysis done by veterinary professionals considering all relevant
factors. Nevertheless, I hope that the mathematical risk assessment will have
better fate than disease eradication mathematical modeling without field
follow-up actions, i.e. without reaching real eradication.
Once again, I would like to thanks for the
interesting exchange of opinion and observations between us on this particular
subject. I hope too that we get the chance to meet us again soon.
Yours
sincerely,
Prof.Dr Vaclav
K o u b a, DrSc.
P.B. 516,
17000
I would like to stress once again the right
of importing country veterinary services authorities responsible for country
protection to decide the conditions asking for zero or for acceptable risk
guaranties and this should be respected by exporting country without any
dictate or imposing other conditions from abroad.