For the Bulletin of the World Health
Organization,
GLOBALIZATION RISK OF ZOONOSES
SPREAD THROUGH INTERNATIONAL TRADE
Prof. Dr
Vaclav Kouba
Former Chief,
Animal Health Service, Food and Agriculture Organization of the United Nations,
Rome, Italy
Present
address: P.B. 516, 17000 Praha, Czech Republic
ABSTRACT
The paper
discuses the risk of zoonoses global spreading through export and import of
animals and their raw products. Many recent cases of specific zoonoses spread
through imported animals have proved that current veterinary conditions,
certifications and measures do not correspond with the new situation. Alarming
danger of introducing zoonoses by import is rapidly increasing due to
intensification of international trade. The paper identifies the factors facilitating
the zoonoses spread which are related to
disease particularities, legal and regulatory arrangements, trade
aspects, veterinary measures and human behaviour. It is called for
strengthening the protection of specific zoonoses free populations, countries
and continents. Trade globalization must not cause diseases globalization.
KEYWORDS : disease spreading - early warning - global threat - international
trade - risk assessment - zoonoses
Introduction
The purpose if this paper is to analyze the
risk of the global spread of zoonoses due to increasing international trade in
animals and their raw products. Import of these commodities represents a
potential risk not only of diseases introduction but also of after-import
spreading with multiplying negative, often long-term or permanent,
consequences. The detection, control and eradication of introduced and spread
zoonoses are usually very difficult and costly. These facts are the main
difference in comparison with the risk when importing any other commodities.
There are many publications documenting
individual specific zoonoses introduction by international trade. Historical review of international trade and
animal diseases including zoonoses was presented by Blancou and Meslin (1).
Data documenting zoonoses introduction by trade were published in statistical
yearbooks of the Food and Agriculture Organization of the United Nations - FAO
(11) and of the International Office of Epizootics - OIE (16) as well as by
individual authors such as Davies (2), Kouba (3,4), Meslin (5,6), Stoehr (7),
etc. The papers dealing with the disease risk published by World Health
Organization (10) and International Office of Epizootics (9,14) are of
particular importance.
Material and methods
a) For the
analysis, official data on zoonoses occurrence in animals and on trade in
animals and their raw products as reported to international organizations were
used.
b) Data on
zoonoses introduction by import of animals were selected from FAO-OIE-WHO
Animal Health Yearbooks (10) and from OIE World Animal Health yearbooks (15).
Particular data collection system was introduced by the author when he was the
Editor-in-Chief of the first yearbook.
c) Data on
international trade in animals and their products were used from FAO Trade
Yearbooks (11). There have been selected the most important animal species and
products. Data on the amount and values
of these commodities cover the period of 30 years between 1965 and 1995. For
the forecasting of probable development linear regression of 1965-1995 data and
2025/1965 index of the amounts as the continuation of previous trend, were
applied.
d) Factors
influencing international spreading such as specific disease particularities,
legal and regulatory arrangements, trade aspects, veterinary measures and human
factors were identified based upon author's experience.
Results
a) Diseases introduction by imported animals
aa) There have been a lot of cases of zoonoses
introduction by import, some of them discovered and reported to international
organizations , some discovered and not reported (e.g., overwhelming majority
of zoonoses in animals are not notifiable and usually not controlled) and much
more cases not discovered at all. Emerging diseases represent a new global
threat (WHO, 10). Due to biological complexity, it is not easy and often
impossible to identify how and when the disease was introduced if discovered
after quarantine period. Examples of officially reported zoonoses introduction
by import into specific diseases free countries see in Table 1.
bb) There have been many cases when, in spite of
favorable risk assessment, risk reducing measures and standard veterinary
certification, specific disease spread through import into a country free of this disease. Of particular
importance for diseases globalization were the introductions from very distant
territories, i.e. from other continents.
Example: Screwworm (Cochliomyia
hominivorax) introduced from Southern America into Africa in 1987; foot-and-mouth disease (FMD) from Southern
America into U.K. in 1967 (spread into 2364 outbreaks; lost of 430000 animals).
cc) An other group is represented by cases in
which different diseases were reintroduced by trade, i.e into countries where
specific disease had been eradicated previously. Examples: FMD was reintroduced
into Italy in 1993 after eradication in 1989; Newcastle disease was
reintroduced into Finland in 1996 after eradication in 1971; screwworm was
reintroduced in USA in 1997 after eradication in 1987.
Cases of introduction of particular
etiological agents into countries where specific zoonosis occurs contributed to
morbidity increase and complicated control programmes.
dd) Not all introduced diseases could be blocked
in the quarantine avoiding creating secondary outbreaks. Examples: Ratios
secondary/primary outbreaks of FMD during 1977-1987: Portugal - 591, Italy -
42, France - 19, Denmark - 10, etc. (Davies, 2).
ee) Not all introduced diseases could be
eradicated or only after longer period requiring a lot of economic and other
inputs. Example: Eradication of the screwworm introduced into North Africa cost
80 million US$ plus local input ( FAO, 15).
ff) Imported diseases represent the risk also for
neighbouring countries (e.g., in case of vectorial diseases). Example:
"For the first time in history, relentlessly destructive New World
screwworm had become established outside its natural range in the Americas and,
if left uncontrolled, it would inevitably spread to neighbouring countries,
eventually into sub-Sahara Africa, Near East and Mediterranean Europe."
(FAO, 14).
b)
Export/import of animals and their raw products
Official international trade data document
increasing risk of zoonoses spreading through export/import of animals and animal
commodities. Absolute export/import data and 1995/1965 indexes as well as
estimates of future development including 2025/1965 indexes see in tables
2,3,4.
If the regression lines are applied for
following 30 years, i.e. up to 2025, then the increase can be estimated in
comparison with 1965 values: in cattle 2.36 times, in pigs 6.97 times, in
sheep/goats 4.27 times, in fresh edible offals 6.32 times, in fresh milk 30.88
times and in eggs in shell 4.07 times.(See tables 2,3,4 and graphs 1,2).
In 1995 the
value of the above mentioned selected commodities reached 58 billion US$ (FAO
Trade yearbook 1996).
c) Other factors increasing globalization risk
Beside the general underestimation of the
alarming danger, there are many factors facilitating directly or indirectly
zoonoses spreading through trade:
aa) When assessing the risk not properly
considering disease particularities such as: real occurrence (lack of complete
and reliable data), stage and dynamics; ways and speed of spreading under given
conditions; spectrum and population size of susceptible animals species;
incubation period, grade of clinical manifestation, carriers; ability of
diagnostic methods to discover all affected herds and animals and their
products (false negative results); availability and feasibility of effective
monitoring, preventive, control and eradication methods and measures;
multi-etiological occurrence and carriers; etc..
bb) Legal and regulatory arrangements: lack of
legal codes requiring effective protection of animal populations and territory
and declaring activity conducing to dangerous zoonoses spreading as criminal
punishable act; benevolent international regulations, i.e. not enough demanding
for protection of importing countries and not respecting that the trade in
animals and their raw products is much more risky than in all other
commodities; missing legal duties for traders to cover direct and indirect
losses caused by disease introduction; etc..
cc) Trade aspects: not applying normal fair trade
practice, i.e. when the importing side is not free to decide if or not and
where to purchase the given animal commodity and to define the health quality
conditions; larger import due to reduction of national animal production (low
self-sufficiency); instable trade partnerships, too many and too distant origin
and destination places; trade agreements unfavourable for importing countries
disease protection or without sufficient guarantee for specific health quality
(disease free) and reclamation procedure; illegal import, black-market,
re-export, dumping prices; etc..
dd) Veterinary measures: lack of or deficiencies
in protective veterinary measures; lack of ability to apply effective
monitoring and control measures, import quarantine and post-import
surveillance; weak government veterinary services being not able to monitor
animal population health situation at field level, to inspect the export/import
on the spot and to issue certificates without being dependent upon not fully
reliable non-government services; benevolent import conditions (unjustified
concessions) reducing barriers against disease introduction instead of
strengthening them; mono-etiological instead of poly-etiological risk
assessment based only on theoretical mathematical calculations without considering
diseases occurrence reality, biological complexity, veterinary services
ability, human factors, possible post-introduction consequences, etc..
e) Human factors: not reporting true situation,
not taking lesson from previous disease introduction, inexperience, errors,
irresponsibility, cheating, corruption, lobbying, risk underestimation,
identity/ health certificates falsification, distrust due to bad experience
with previous import, abusing "disease regionalization", low
discipline when implementing of regulations and measures, etc.
Discussion
The results reconfirm the anxiety of many
authors such as Blancou & Meslin (1) about the risk of zoonoses spread
through international trade. The
presented facts on zoonoses introduction by trade and on increasing global
export/import in animals and their raw products are self- explanatory. It is
obvious that the grade of global risk is directly correlated with trade size
and frequency as well as with the number and distances between origin and destination
places.
Controlling only a few selected diseases
and confirming their "free status" in exporting animals and products
means omitting not notifiable, not internationally controlled and new emerging
diseases. Therefore, it can be supposed that among imported animals and their
raw products can be carriers of etiological agents which for importing country
are considered as exotic species, types, subtypes or strains. Not all can be
controlled. Absolute "filter" doesn't exist. In spite of the best
possible protective measures, disease introduction cannot be always avoided.
This is the reason for minimizing international animal trade size, frequency,
number of origin and destination places and distances.
Example: In 1972 Czech Republic being eight
years free of Brucella abortus (BA)
decided as exception to import about one thousand heifers from officially BA
free region and ranches of a neighbouring country after sending specialists to
reconfirm the situation. After series of pre-import and post-import complex
serological investigations with negative results (quarantine up to first
calving), imported animals were distributed into several farms of a ranch and
systematically tested with negative results. However during second calving the
brucellosis "exploded" and all imported animals and thousands heads
of local cattle must go to slaughter. Several persons became sick.
Animal disease import risk is generally
underestimated giving priority to instantaneous profit ignoring the potential
disease spread and consequences, often irreparable. There were hundreds of
cases of importing diseases which destination country was not able to control
and eradicated them. The losses and cost of measures have been usually very
high. Most of introduced diseases, mainly chronic without clinical
manifestation, if widely spread and particularly if penetrated among wild
animals are today almost impossible to eradicate and negative consequences can
last for ever.
The impact of disease introduction can be
disastrous. It is difficult to accept the practice when post-introduction
losses and cost of measures are covered by government budget (by tax-payers)
only and not by profiting traders who usually do not contribute anything. In
all other commodities the traders must cover losses due to hidden defects.
Today's extreme pressure of international
organizations such as World Trade Organization (8) and traders to limit
protective import conditions, general tendency to reduce trade controlling
government veterinary services (e.g., the proportion of government
veterinarians decreased from 34 % in 1983 to 25 % in 1996) and to restrict
animal health programmes as well as disease testing can cause much worse and
difficult-to-solve situation for the generations to come. E.g. from 1997
international reporting system was significantly reduced eliminating previous
grading of animal diseases occurrence and information on the disease
introduction, i.e on occurrence in imported animals (in quarantine). This means
less information on diseases occurrence than before computer era !
For exporting country is easier and cheaper
to manage importing country to reduce protection barriers than demanding
diseases reduction/eradication programmes at home. Recently was introduced so
called "disease regionalization", when in spite of unfavorable and
instable disease situation (which in the
past blocked the export) the exporting country declares one or several
"islands" of territory also without their borders' control (usually
without international clearance) as "specific disease free" and the
export can go on. Very complicated network of daily transfer of animals and
their products within the country or block of countries without internal
borders' inspection, is almost impossible to control by veterinary services. In
the past these territories were understood for export purposes as one unit and
thus reducing the risk of diseases spreading outside the country.
The principle to protect specific diseases
free populations and territories should be defended in spite of strong pressure
and unilateral monetary arguments. The trade in animals and their products is a
big business. If we consider reported value of the import of all animal species
and products including illegal trade, then globally the annual estimate is
about one hundred billion US$.
International trade organizations press
importing countries to justify the refusal to import what they do not want when
assessing disease introduction risk, i.e. ask for scientific evidence
supporting the need for the trade restriction. This discriminating demand is
not applied in any other goods. How to evaluate "scientifically" all
introduction risk criteria, in particular the non-biological ones ?
Every import of animals and their raw
products is a risk of diseases introduction. Increasing intensity of
international trade in animals and raw animal products causes increasing spread
of zoonoses among the countries and continents. The situation is getting worse
every day as never before in spite of having much better scientific knowledge
as in the past. Imminent risk of the globalization calls for urgent revision of
existing leaky measures with the aim to achieve much better protection of
specific diseases free populations, territories and countries.
Conclusion
All cases of disease introduction to be
analyzed and correcting measures applied. To reinforce countries protection,
the factors increasing zoonoses introduction risk, as presented above, to be
avoided. The key criterium of the country and continent protection measures
effectivity is practical result avoiding animal diseases introduction.
In importing countries the
increase of animal production to be supported, i.e. to be self-sufficient as
much as possible and thus to reduce the need for risky import. The protection
of country territory is the first responsibility of any official veterinary
service. Therefore, it must have the right to make the final decision about the
import conditions which has never been easy due to disparate interests.
In order to transfer into field
practice extremely useful
recommendations and methods for zoonoses prevention and control elaborated by
WHO, mostly in collaboration with FAO and OIE, government veterinary services
must be significantly reinforced, to be able to cope with the new situation
defending community interests effectively .
Alarming risk linked with increasing trade
requires to revise urgently national and international regulations such as of
WTO (8) and OIE (12) and to adjust them to the new developing situation and
conditions strictly defending specific zoonoses free populations and
territories.
General tendency in international trade is
to increase the quality requirements on the commodities. Trade in animals and
their products must not be the exception. Improvement of animal health quality
of exporting countries through diseases
reduction and eradication is the best way how to facilitate the trade in these
commodities. Trade globalization must not cause globalization of zoonoses. The
priority should be given to globalization of the health.
References
1. Blancou J, Meslin FX. International trade and human or animal
diseases: a historical review. Proceedings of the World Veterinary
Congress, Yokohama, 1995,p.4.
2. Davies G. Risk assessment in practice: a foot and mouth disease control strategy
for the European Community. Rev.sci.tech.Off.int.Epiz., 1993, 12(4),
1009-1119.
3. Kouba V. [General epizootiology], 2nd edit. Havana, Edicion Pueblo y Educacion,
Instituto del Libro, 1987 (in Spanish), 867 pp.
4. Kouba V. Computerized methods for animal health risk assessment using the EPIZOO
2.6 program. Rev.sci.tech. Off.int.Epiz., 1997, 16(3), 793-799.
5. Meslin FX. Surveillance and control of emerging diseases. World Health
Statistics Quarterly, 1992, 45, 2/3, 200-207
6. Meslin FX. Zoonoses in the world: current and future trends. Schweiz. med.
Wochenschr., 1995, 125
7. Stoehr K. Prevention and control of foodborne Salmonella. Southeast Asian
J.Trop.Med.Pub.Health, 1995
8. Agreement on the Application of Sanitary
and Phytosanitary Measures. In: The results of the Uruguay Round of
multilateral trade negotiations: the legal texts. GATT. World Trade
Organization (WTO), Geneva, 1994, 69-84.
9. Contamination of animal products: prevention
and risk for public health. Rev.sci.tech. Off.Int.Epiz, 1997, 16,2.
10. Emerging and re-emerging infectious
diseases: WHO responds to a global threat. Press release WHO/37, 26 April
1994
11. FAO-OIE-WHO Animal Health Yearbook
1981-1995. Rome, FAO, 1982-1996.
12. FAO Trade Yearbook 1965-1995. Rome,
FAO, 1966-1996
13. International Animal Health Code, Special
edition 1997. International Office of Epizootics, Paris, 1997, 642 pp.
14. Risk analysis, animal health and trade.
Rev.sci.tech. Off.int.Epiz., 1993, 12(4), 1005-1362.
15. The New World Screwworm Eradication
Programme, North Africa 1988-1992. FAO, Rome, 1992, 192 pp.
16. World Animal Health 1990-1997. International
Office of Epizootics, Paris, 1991-1998.
Tables
Table 1.
Examples of zoonoses occurrence in imported animals (quarantine) only
Table 2. World
export/import of cattle, pigs and sheep/goats as reported during 1965-1995 and
estimates for years 2000-2025
Table 3. World
export/import of meat as reported during 1965- 1995 and estimates for years
2000-2025
Table 4. World
export/import of fresh offals, milk and eggs as reported during 1965-1995 and
estimates for years 2000-2025
Figures
Figure 1.
Export/import of pigs in the world (reported, trend)
Figure 2.
Export/import of meat in the world (reported, trend)
Into Word 7 –
April 2000