WORLD TRADE  
ORGANIZATION  G/SPS/GEN/625 
23 January 2006 
 (06-0299) 
Committee on Sanitary a nd Phytosanitary Measures Original:   English/ 
 French/  Spanish 
 
   
OIE ACTIVITIES ON ZONING AND COMPARTMENTALIZATION 
 
Communication from the World Organization for Animal Health (OIE
) 
  
 The following communication, received on 19 January 2005, is being circulated at the request 
of the OIE. 
_______________ 
 
Official recognition of disease status by the OIE 
 
1. The OIE has a mandate to examine upon request  from a member country its claims for a 
particular status with regard to four of the OIE listed diseases for terrestrial animals: foot and mouth 
disease (FMD), rinderpest, contagious bovi ne pleuropneumonia and bovine spongiform 
encephalopathy (BSE).  With regard to BSE, Memb er Countries may apply to be recognized for only 
one of two categories of status (of the five in th e current BSE chapter of the OIE Terrestrial Animal 
Health Code (the Terrestrial Code)) – free and provisionally free. 
2. The OIE does not routinely classify its Member C ountries with respect to their animal health 
status for other listed diseases.  However, it publis hes information received from the delegates of 
Member Countries with regard to their status for other listed diseases and for emerging diseases.  Some Member Countries have suggested that the diseases for which the OIE officially recognises 
health status be increased to include avian influenza (AI) and classical swine fever (CSF). 
3. The recognition procedure requires that the memb er country provide evidence that it complies 
with all the relevant provisions of the Terrestrial  Code and Manual with respect to the disease for 
which free status is being sought, either for the w hole country, or for a zone or compartment within 
the country. 
4. As the procedure concludes with an official recognition by the OIE of the status of the 
member country for that disease (through a formal resolution adopted by the International Committee 
of the OIE at its General Session), other OIE Memb er Countries have an obligation to take that 
recognition into account when developing import hea lth measures for commodities from that member 
country, to maximise the harmonisation of thei r measures with international standards.  
5. Full details of the OIE process are provided in documents G/SPS/GEN/542 and 
G/SPS/GEN/542 Add1. G/SPS/GEN/625 
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  Zoning and compartmentalization 
 
6. The Terrestrial Code  chapter on zoning and compartmenta lization provides general guidance 
to OIE Member Countries seeking to establish and ma intain different animal subpopulations within 
their national boundaries using the procedures descr ibed.  The chapter al so outlines a process for 
trading partners to follow in achieving recognition of the health status of such subpopulations.  These 
procedures are best implemented by trading part ners through establishing pa rameters and gaining 
agreement on the necessary measures prior to di sease outbreaks, rather than during outbreaks. 
As well, specific requirements have been devel oped or are being developed for diseases for which the 
application of zoning or compartmentalization is considered appropriate; for example: 
• The Terrestrial  Code  chapter on FMD gives detailed technical recommendations for a country 
or zone to be considered free from FMD, with  or without vaccination.  Recommendations for 
free compartments are under consideration but the manner in which the disease spreads presents  difficulties. 
 
• The Terrestrial  Code  chapter on avian influenza gives detailed technical recommendations for 
a country, zone or compartment to be considered  free from all types of avian influenza or free 
from the highly pathogenic form only. 
 
• The Terrestrial  Code  chapter on BSE gives detailed tec hnical recommendations for a country, 
zone or compartment to be considered of negligible BSE risk or controlled BSE risk. 
 
• The proposed revised Terrestrial Code  chapter on classical swine fever (CSF) gives detailed 
technical recommendations for a country, zone or compartment to be considered as free from 
CSF, and addresses the disease in domestic and wild pigs. 
 7. It should be noted, however, that the applicati on of zoning or compartmentalization is not 
mandatory, and should only be used when appropri ate, taking into account the epidemiology of the 
disease and the particular factors applying in each situation.  These particular factors may include 
environmental factors (e.g., the presence of natu ral boundaries), the level of surveillance for the 
disease, the quality of veterinary services or other competent authorities, and the ability to apply 
appropriate biosecurity measures. 
OIE concept paper on compartmentalization 
 
8. A provisional draft of an OIE concept paper on compartmentalization, which has been 
developed to enhance the understa nding of Member Countries of the concept of compartmentalization 
and to suggest criteria and guidelines for the a pplication of this concept, is attached. 
  G/SPS/GEN/625 
 Page 3 
 
 
  Attachment 
   
OIE CONCEPT PAPER ON COMPARTMENTALIZATION 
 
 
A provisional draft for discussion at the General Session  
of the OIE International Committee in May 2006 
 
December 2005 G/SPS/GEN/625 
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  Introduction 
 
The objective of this document is to describe the c oncept of a “compartment” and to develop criteria 
and guidelines for the application of this concept.  
The difficulty of establishing and maintaining a disease free status for an entire country, especially for 
diseases the entry of which is difficult to control at national boundaries, has been acknowledged.  For 
many diseases, OIE Member Countries have traditiona lly applied the concept of zoning to establish 
and maintain an animal subpopulation with a diffe rent animal health status within national 
boundaries.  Recently, the concept of compar tmentalisation was introduced to the OIE Terrestrial 
Animal Health Code (the Terrestrial Code ) and the OIE Aquatic Animal Health Code  as an alternative 
way to manage disease and pathogens in animal popul ations without unnecessarily disrupting trade.  
Regionalisation or zoning can be thought of as rec ognising animal subpopulations of differing health 
status based on geographical boundaries, while  compartmentalisation is based primarily on 
management practices and biosecurity.  However, spatial considerations and good management 
practices play a role in the application of both c oncepts.  Compartmentalisation is not a new concept 
for Veterinary Services; in fact, it has been  applied for a long time in many disease control 
programmes that are based on the concept of di sease-free herds/flocks.  Examples of such 
programmes include tuberculosis, brucellosis and pse udorabies.  The intent of this document is to 
provide a structured framework for the application and recognition of compartments within countries 
or zones.  
The fundamental requirement for application of either concept is that the animal population 
considered for trade maintains a functional separa tion through management or geographic boundaries 
that allow a clear epidemiological differentiation from populations of higher risk.  For example, a 
confinement operation of  poultry or swine might have biosecurity measures and management 
practices that result in virtually zero risk from diseas es or agents in the same geographic area.  On the 
other hand, a geographically isolated population of animals or birds might have substantial risk from 
travellers, tourists, or other l ong range epidemiological links.  Thus the concept of a compartment 
extends the application of a “risk boundary” beyond that of a geographic interface and considers all 
epidemiological factors contributing to a functional separation that creates an effective boundary. 
The main criterion for a compartment is that the an imals contained in it are clearly recognisable as 
part of a unique subpopulation with limited or no epidemiological links to other populations of risk.  
The measures taken to ensure the identificati on of the sub-population and the recognition and 
maintenance of its health status should be documented in detail and mu st take into consideration the 
epidemiologic characteristics of the disease in question.  
In disease control strategies the compartments should be defined prior to the occurrence of the 
outbreak.  Following a disease outbreak, compartmentalisation may be able to take advantage of epidemiological linkages among groups of animals desp ite diverse geographical locations, to facilitate 
disease control.  
For the purpose of international trade, compartm ents should be under the direct control and 
responsibility of the official Veterinary Administration  in the country.  G/SPS/GEN/625 
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  Definitions 
  
The following definitions have been adopted for the Terrestrial Code (the definitions in the Aquatic 
Code are very similar): 
Zone/region 
means a clearly defined part of a country cont aining an animal subpopulation with a distinct 
health status with respect to a specific diseas e for which required surveillance, control and 
biosecurity measures have been applied for the purpose of international trade. 
 
Compartment  
means one or more establishments under a common biosecurity management system 
containing an animal sub-population with a distinct  health status with respect to a specific 
disease for which required surveillance, control and biosecurity measures have been applied 
for the purpose of international trade.  
 
Establishment  
means the premises in which animals or birds are kept.  
 
Seven factors for evaluation a nd recognition of a compartment 
 
1. Definition of the compartment 
A compartment is an animal subpopulation with a de fined status in respect of the conditions of 
interest, a geographical identity and integrity in maintenance of its membership and status.  The 
compartment must be clearly defined, indicating th e functional relationships of all its components and 
their contribution to an epidemiological boundary  between the animals in the compartment and 
populations of higher risk.  The definition of  compartment may revol ve around common animal 
ownership or management, membership in associ ations, industry improvement plans or breed 
registries with prescriptive biosecurity guide lines, or similar functional demarcations. 
 The compartment may also be defined by disease sp ecific factors.  For example, a cattle population 
may be defined as a BSE free compartment dependent primarily on careful historical documentation of feed sources, animal movements and identificati on.  Alternatively, a swine confinement operation 
might be defined by the ability of its biosecurity pl an to exclude infectious agents on a day to day 
basis.  In the poultry industry, a compartment may be defined on the basis of a slaughter plant and all the establishments that supply birds to it as well as those establishments that are vertically integrated 
with the operation.  In general, a compartment is defined by the f actors common to a population that provide distinct 
disease risk separation from animals or birds at higher risk for the disease(s) in question.  
 
2. Epidemiologic separation of the compartm ent from potential sources of infection 
Epidemiological parameters comprise a major porti on of the defining criteria for a compartment. 
These factors relate to pathways of disease transm ission, mitigations to prevent exposure, disease 
specific factors, and environmental factors that affect exposure and propagation of the disease agent. 
 (a) Biosecurity in respect of health related issues G/SPS/GEN/625 
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  The biosecurity plan should address potentia l pathways for introduction and spread of 
infection into the compartment.  In add ition to detailing disease introduction pathways, a 
biosecurity plan should provide standard operating procedures that mitigate exposure from each pathway and describe a plan for the implementation and monitoring of compliance with the procedures.  Finally, the plan should include means for education and training of workers 
to ensure that all persons involved in bi osecurity are knowledgeable and informed.  
(b) Physical, spatial, or location factors that affect  the status of biosecurity in the compartment 
While a compartment is primarily based on biosecurity measures, a review of geographic 
factors is needed to ensure that the functiona l boundary provides adequate separation of the 
compartment from adjacent high risk animal popul ations.  The following considerations are 
taken in conjunction with biosecurity measures and, in some instances, may alter the degree 
of confidence achieved by general bi osecurity and surveillance measures. 
y Disease or pest status in areas adjacent, or  with unmanageable epidemiological links 
to the compartment. 
y Location of nearest flocks or herds.  Are the facilities within the compartment 
immediately adjacent to flocks or herds of higher risk or is there a buffer area that 
would preclude direct contact or aerosol spread? 
y Consideration of environmental spread of the disease agent.  Are aerosols a factor in 
the transmission of the disease-causing agen t? Is the climate such that agent 
survivability would be extremely brief or extremely prolonged? 
In any case, sufficient evidence should be submitte d to assess the efficacy  of the biosecurity 
plan in accordance with the level of risk fo r each identified pathway.  The compartment 
should periodically assess the biosecurity risk of  all operations through a formal process using 
a survey instrument designed to identify high ri sk aspects.  Based on the outcome, concrete 
and documented mitigation steps should be taken to reduce areas  of high risk for introducing 
the agent. 
(c) Identification and registration 
A prerequisite to assess the integrity of the membership of the compartment is the existence 
of a valid traceability system.  All animals w ithin the compartment should be identified in 
such a way that their individual history can be audited.  Depending on the system of production, identification may be done at the herd , flock, lot or individual animal level.  All 
animal movements into and out of the comp artment should be certified by the official 
veterinary service and documented.  G/SPS/GEN/625 
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  Table 1.  General considerations of compartmen tal biosecurity: pathways of entry of disease 
agents and responsive mitigations 
 
Potential pathways of entry  Examples of responsive mitigations  
Endemic compartments No interactions with endemic compartments.  Biosecurity 
practices protect farm site from neighbouring 
herds/flocks (also see employee policy). 
Wild populations Animals in the free compartment should be housed in a 
way that provides adequate separation from other wild 
populations (e.g. wild boars, wild birds) 
Employees Policy prohibiting employees’ contact with high risk 
animals. e.g. in the poultry industry a policy preventing employees from owning or handling birds off farm or attending avian shows or exhi bitions; shower, dedicated 
clothing/footwear 
Training 
Service sectors (e.g. Catching/vaccination/cleaning 
crews/feed delivery/service personnel) Require use of disposable or dedicated clothing/footwear 
Require that they not have been on another farm same 
day Require truck/equipment cleaned and disinfected before coming on farm 
Congregation of sick/dead animals from multiple sources (e.g., rendering) Compost, incinerate, or bury dead animals 
e.g. for poultry, covered barrel at perimeter of property – dead birds placed in bags in barrel 
Vehicle traffic Park away from animal housing, preferably outside farm 
perimeter 
Only essential vehicles enter premises (e.g., feed truck) 
Spray station at entrance – use on own vehicles as well as others 
Visitors Prohibit visitors in animal area 
Fences, signs, locked gates, or guards to discourage entry 
Wild animals No attractants such as garbage 
Fencing House production animals indoors 
Aerosol Prevention of possible aerosol-borne infection by 
distance or other specific measures such as air filtration 
systems. 
Vectors Vector proof housing.  Verify the integrity of screens 
regularly. 
Equipment Do not share equipment with other farm sites, including 
same parent company 
Dedicated racks and flats (e.g., colour coded) – thoroughly cleaned and disinfected between uses 
Downtime Minimum downtime between flocks or litters? 
Cleaning and disinfection E.G for poultry: number of flocks before change litter? 
 G/SPS/GEN/625 
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  3. Documentation of factors critical to  the definition of compartment 
Standard operating procedures should be in place to  document all operations of the compartment.  
Documentation must provide clear evidence that  the biosecurity, surve illance, traceability and 
management practices are adequate to meet the defin ition of the compartment.  In addition to animal 
movement information, the necessary documentation should include herd or flock production records, 
feed sources, surveillance tests, birth and deat h records, visitor logbook, morbidity history, 
medications, vaccinations, biosecurity plans, do cumentation of training and any other criteria 
necessary for evaluation of disease exclusion.  The historical disease status of the compartment has to be documented, indicating the dates of last 
disease occurrence (if any), the number of outbreaks and the methods for disease control that were 
applied.  Vaccination status for many diseases must be  considered in regard to the interpretation of 
surveillance data.  The type of vaccine and frequency of administration are needed in many cases to 
evaluate test results and to determine the risk  of the disease in the population.  Therefore, 
documentation of vaccine-related factors must be  maintained for a period of time based on the 
disease, vaccine types and production cycles. 
 The information contained in the records may vary according to the species and disease(s) under 
consideration.  For example, in a disease such as BSE that is stric tly transmitted by feed, with a long 
incubation period, complete records of all feed  sources for several years would be essential to 
recognise the compartment.  On the other hand, hist oric feed records would be of little value for a 
highly contagious disease such as avian influenza. 
 
4. Supervision and control of the compartment 
The authority, organisation, and infrastructure of the veterinary services, including laboratories, must 
be clearly documented in accordance with the chapter on the evaluation of veterinary services of the 
OIE Terrestrial Code , to provide confidence in the integrity of the compartment 
 Official oversight of biosecurity and surveillance is an essential component of compartmentalisation.  
The supervision of the factors critical to maintena nce of a compartment status should be developed 
through cooperation of in dustry and government veterinary ser vices.  The final authority for the 
purposes of domestic and international trade lies within the official Veterinary Services .  All 
production within the compartment should be carried out according to a single standard of operation. 
 Industry’s responsibilities in most cases will include the application of biosecurity measures, quality 
assurance schemes, monitoring the efficacy of the measures, documenting corrective actions, 
conducting surveillance sampling, rapid reporting and maintenance of records in a readily accessible 
form.  A HACCP approach may be an appropria te tool with which to design and apply these 
measures.   The Official Veterinary Services  with authoritative responsibility fo r international trade will provide 
movement certification, periodic inspections of fac ilities, biosecurity measures, records, surveillance, 
and sampling procedures.  Official  Veterinary Services  should conduct surveillance and sampling and 
they will conduct or oversee laboratory diagnostic examinations.  The extent of oversight and 
frequency of inspections must be adequate to provi de reasonable confidence to trading partners that 
the measures defining the compartment are applied in a manner that meets the importing country’s appropriate level of protection.   G/SPS/GEN/625 
 Page 9 
 
 
  5. Surveillance for the agent or disease 
(a) Surveillance should involve the collection and anal ysis of disease/infection data such that the 
official Veterinary Services  have confidence that the flocks or herds comply with the defined 
status of a compartment.  A surveillance system that is able to ensure early detection in the 
event that the agent enters a flock or herd is  essential.  The surveillance system should comply 
with the General Guidelin es for Surveillance in the Terrestrial Code  and the specific 
guidelines for surveillance fo r the disease of interest.  
(b) Depending on the disease of interest, many different  combinations of testing and surveillance 
may be applied to achieve the desired c onfidence in disease freedom.  The surveillance 
methodology will usually follow OIE guidelines bu t may utilise a demonstrably equivalent 
method.  Based on an assessment of risk factors, a country may choose to sample with greater 
intensity in areas of higher risk and less so in other areas that have a documented lower risk.  
In general, an appropriate combination of  active (ongoing laboratory-based testing) and 
passive (voluntary intermittent reporting or tes ting) is necessary to achieve the surveillance 
goals described above.  A system for reporting the results of surveillance testing must be 
documented and efficacious to inform veterina ry officials and trading partners of positive 
tests, abnormal clinical signs and production ob servations that are included in the surveillance 
strategy.  Surveillance information must be reported immediately by the compartment management and field veterinary officials res ponsible for surveillance and monitoring of the 
disease. 
6. Diagnostic capabilities 
Officially designated laboratory facilities complyi ng with the OIE standards for quality assurance as 
defined by the OIE Manual for diagnostic Tests and Vaccines  for terrestrial and aquatic animals 
should be available for sample testing.  The labor atory tests and their use should be audited by the 
national authority.  In particular, laboratories a nd personnel performing the t ests should be trained and 
certified by the national reference laboratory as to competency.  Periodically, the laboratories and 
personnel should complete a proficiency test to ve rify continuing competence.  Reporting of test 
results should be transparent.  
7. Emergency response, control, and notification capability 
Rapid diagnosis, reporting, and notification of disease ar e critical to minimising risk from outbreaks.  
The structure of the compartment must be such that producers and their employees are aware of the 
notifiable diseases and procedures for reporting.  Li kewise, each laboratory that conducts surveillance 
testing must have systematic procedures in place for rapid reporting of disease results to authoritative 
government officials.  The veterinary authority mu st then have standard operating procedures to 
inform the OIE and if necessary, other pertinent international bodies.  
 
Sequence of steps to be taken in defining a compartment 
  
There is no single sequence of steps which must be followed in defining a zone or a compartment.   
The steps that the veterinary services of importing and exporting countries choose and implement will 
generally depend on the circumstances existing within a country and at its borders.  The 
recommended steps are:   G/SPS/GEN/625 
Page 10  
 
  o based on discussions with the relevant enterprise/industry, the exporting country 
identifies within its territory one or more est ablishments or other premises owned by an 
enterprise(s) which operates under a common bi osecurity management system, and which 
it considers contains an animal subpopulation with  a distinct health status with respect to 
a specific disease/specific diseases; 
o the exporting country assesses through a form al process compliance with the seven 
factors described above 
o the exporting country identifies such an enterprise to be a free compartment, in 
accordance with the measures stipulated in the Terrestrial or Aquatic Code; 
o the exporting country provides the informa tion above to the importing country, and 
proposes that such an enterprise be treat ed as an epidemiologically separated 
compartment for international trade purposes; 
o the importing country determines whethe r it may accept such an enterprise as a 
compartment for the importation of animals and animal products, taking into account: 
 an evaluation of the exporting country's Veterinary Services/competent 
authorities, according to the OIE Codes; 
 its own animal health situation with respect to the disease(s) concerned; and 
 other relevant OIE standards;  
o the importing country notifies the exporting country of its determination and the 
underlying reasons, within a reasonable period of time, being either: 
 recognition of the compartment; in which case, the importing country and the 
exporting country may enter into a formal agreement defining the compartment; 
 request for further information; or 
 rejection of such an enterprise as a comp artment for international trade purposes; 
Official recognition of animal health status 
 
The OIE has a mandate to examine upon request from a Member Country its claims for a particular 
status with regard to four of the OIE listed diseases: foot and mouth disease (FMD), rinderpest, 
contagious bovine pleuropneumonia and bovine spongiform encephalopathy (BSE).  The OIE does 
not routinely classify its Member Countries with respect  to their animal health status for other listed 
diseases. 
The procedure requires that the Member Country provide evidence that it complies with all the 
relevant provisions of the Terrestrial Code and Manual with respect to the disease for which free 
status is being sought, either for the whole country, or for a zone or compartment within the country.  
While at present free status recognition is confined to countries and zones, as the use of the concept of 
compartmentalisation broadens within the Terrestri al and Aquatic Codes, official recognition of 
claims for free status of compartments will follow.  
As the procedure concludes with an official rec ognition by the OIE of the status of the Member 
Country for that disease (through a formal resoluti on of the OIE International Committee), other OIE 
Member Countries have an obligation to take that  recognition into account when developing import 
health measures for commoditi es from that Member Country.  G/SPS/GEN/625 
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  Conclusion 
 
OIE Member Countries have continuously striven to  facilitate risk-based trade in the face of the 
challenges represented by disease prev alence in the livestock and poultry populations involved.  In 
recent years, regionalisation/zoning was introduced as a means for trading from a sub-national area in 
an otherwise infected country.  This requires that the official Veterinary Services  exert control at the 
region/zone level equivalent  or superior to that at the national level.  
Compartmentalisation is a tool that may also be applied to facilitate trade.  Fundamental to its 
application is the official Veterinary Services ’ control over the compartment and the free exchange of 
information necessary to convince importing countries  that the risk of disease introduction from trade 
is minimised.  Therefore, the procedures for establishing trade based upon the compartmentalisation 
concept should be similar to those prac tised for regionalisation or zoning.  
All disease control approaches require the combined contributions of nationa l veterinary services and 
individual producers.  Compartmentalization requires a higher relative investment of resources per unit of animal production by the producers and the veterinary services than zoning or national disease 
control programs.  A compartment is analogous to  the initial phase in traditional national disease 
control programs (tuberculosis, brucellosis, pse udorabies) in which producers, under the official 
veterinary service supervision, decided for trade pur poses to establish individual herd status superior 
to that to the general herd population. 
The preceding guidelines provide a basis for establishi ng, evaluating and excha nging information on 
compartmentalised animal populations in the interest of international trade.  As in the case of similar 
national or zoned/regionalised applications, the re lated trade decisions are ultimately determined by 
the importing country’s assessment of whether its acceptable level of risk can be met during the 
commercial transaction. 
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