An Independent Review of New Zealand's Biosecurity Surveillance Systems-Farmed Livestock and Domestic Animals

Background & Disclaimer

Farmed Livestock and other Domestic Animals

Includes: Diseases of farmed livestock (both mammalian and avian), horses and companion animals. Surveillance has been recognised as important to this sector for many years. For this reason it has been regarded, by many, as "mature".

Risk factors specific to the sector:

• The health status of legally imported animals and their germplasm is well controlled through the requirement for them to meet Import Health Standards based on thorough scientific risk analyses;
• The lengthy delays in the completion of risk analyses and the development of Import Health Standards creates an environment in which illegal importation of risk goods is more likely;
• Given the current border security standards, the illegal importation of most species of live animals within the scope of this "sector" would be difficult;
• International trafficking of some very high values species (particularly birds and bird eggs) is recognised and illegal importation of these species almost certainly occurs;
• Some of the diseases of livestock are transmissible through animal products and/or fomites;
• Increases in the ethnic mix of the New Zealand population have led to increased demand for the traditional foods of other countries. Numerous attempts to import animal products and other risk goods are intercepted at the border. It must be assumed that some attempts to import these goods are successful;
• International tourists (particularly those who prepare their own meals and those who camp on or visit farms) present high of an average risk of importing disease organisms either in their legally imported animal products or on other goods brought with them;
• 100% inspection of mail and of incoming passengers and their baggage cannot assure 100% detection of risk goods carried by them;
• Illegal importation of germplasm is feasible;
• The potential for the illegal importation of disease-causing organisms was demonstrated with the importation of Rabbit calicivirus;
• Passive Surveillance for BSE has been found to be unacceptable internationally. Trade with Europe would be at risk without the implementation of a specific Surveillance programme for that disease;
• Current international trends (particularly in Europe) are expected to results in the requirement for proof of absence of Scrapie from New Zealand using methods similar to those implemented for BSE if trade is to be protected;
• This trend may develop to include more stringent demands for "proof of absence" from other diseases;
• The potential impact of any incursion of an OIE list A disease on the economy of New Zealand would be significant. Detection sufficiently early to allow rapid eradication would limit the damage. New Zealand would have great difficulty finding the resources for rapid eradication of any major epidemic disease unless it was detected very early;
• An epidemic of a highly contagious animal disease (even a relatively small fraction of the size of the recent Foot and Mouth and Disease outbreak in Great Britain) would exhaust resources available within the country for its control.

Surveillance objectives:

The animal disease Surveillance objectives specified by MAF Animal Biosecurity are:

• To facilitate the export trade in animals and animal products by being able to credibly certify New Zealand's true disease status, therefore minimising the sanitary requirements that these exports must meet;
• To fulfil international treaty obligations, including the prompt reporting of animal health events to international organisations and trading partners;
• To develop and establish technically justifiable import requirements for animals and animal products entering New Zealand;
• To enable the prompt notification of exotic diseases in New Zealand;
• To support the development of pest management strategies to control animal diseases;
• To facilitate the formulation of public health policies for the control of animal diseases that can affect human health.

Surveillance processes:

• The reporting of suspect exotic diseases by animal owners or veterinary practitioners to MAF through an 0800 number which is widely advertised. Appropriate follow-up is determined on the basis of the information received;
• "Passive" disease Surveillance through veterinary diagnostic laboratories. This information is dependent upon observation, examination and referrals through a chain of animal owners, veterinary practitioners, diagnostic laboratories and MAF's Animal Health Reference Laboratory;
• A Surveillance programme for BSE based on financial incentives for farmers and veterinary practitioners to submit material from particular case types to diagnostic laboratories;
• An active Surveillance programme for arboviruses (particularly targeting Bluetongue and based on serological testing of cattle in sentinel herds) and for the vector Culicoides spp. (using light traps);
• An active Surveillance programme for BSE. This programme is termed the "MAF BSE Trade Risk Mitigation Programme" and is funded by the meat industry;
• Periodic serological surveys for diseases considered to be exotic. Such surveys, generally, target disease organisms which have the potential to be present in the absence of clinical disease;
• Companies in the broiler poultry industry maintain intensive screening of grandparent and parent flocks for a limited range of potential epidemic, exotic poultry diseases.

Strengths:

• Documentation of requirements in standards and securing of supply through contracts and MOUs [93][94][95][96][97];
• The extensive contacts between veterinary practitioners and farmers, especially in the dairy industry [98];
• A generally high level of diagnostic competence amongst veterinary clinicians;
• The extensive use of veterinary diagnostic laboratories by many veterinary practitioners;
• A high level of training and skills amongst veterinary laboratory diagnosticians;
• A high level of diagnostic competence at AHRL and NCDI.

Weaknesses:

• The animal disease Surveillance programmes are primarily directed at the detection of new incursions into New Zealand and the meeting of international reporting requirements, yet: _ Programmes are not designed for the monitoring of diseases considered endemic in New Zealand and data collected are rarely used for that purpose; _ Claims that diseases are not present in New Zealand are, generally, based on those diseases not having been diagnosed. Some claims are supported by negative findings in serological surveys of varying sensitivities. Robustness of claims of absence of disease on these bases are dependent upon case numbers and on sizes and timings of surveys. _ Many of the claims would be found to be weak if challenged. The BSE Trade Risk Mitigation Programme was developed in the face of such a challenge;
• The absence of a defined strategy for animal disease Surveillance;
• The absence of defined technical objectives. (Required sensitivities should be expected to be different for different organisms based on the epidemiology of the organism, its probable impact on New Zealand well being and the tools available for its control);
• Differences between the basis upon which the list of targeted organisms for Surveillance was developed (Stone, 2001) and the stated purposes of the Surveillance programme (MAF, 2002a). (The list of target organisms was developed through a process identifying which animal disease-causing organisms should be targeted by a response should they be diagnosed in New Zealand, with potential production impacts being a major basis for decision-making. The major purposes for the current Surveillance programme are stated to be trade support and international reporting);
• A lack of prioritisation within a long list of organisms targeted within the Surveillance programme;
• The absence of a list of diseases targeted by the first objective (i.e. being able to credibly certify New Zealand's true disease status);
• A lack of systematic evaluation of the most appropriate Surveillance tools for the individual diseases targeted;
• An absence of targeting of most probable pathways for entry of diseases. (e.g. The most probable pathway for entry of FMD is illegally imported animal products being fed to pigs [99] and the same must also be true for Swine Fever and African Swine Fever, yet there is no Surveillance specifically targeted and that pathway);
• The lack of a database detailing animal disease organisms recognised in New Zealand;
• The relatively low level of usage of veterinary practitioners and diagnostic laboratories for the diagnosis of cases of clinical illness and death (especially in sheep, beef cattle and poultry) [100][101][98];
• A lack of understanding of the animal owner - veterinary practitioner - diagnostic laboratory infrastructure within New Zealand by those with responsibility for animal disease Surveillance systems in MAF;
• The lack of promotion and development of the concept of reliance of Surveillance on the flow of diagnostic material through an infrastructure commencing with the farmer and ending with information provided to MAF. (This results in a lack of commitment to the concept of Surveillance being a service with real value);
• Poor communication and relationships between MAF, NCDI and some diagnostic laboratories;
• A lack of in-depth investigation of unusual disease incidents or syndromes of unknown aetiology. (Provision is made for this type of work to be carried out by diagnostic laboratories (or others) yet the available funds have not been drawn on for at least two years);
• The view by some laboratory staff that some of the technical aspects of the Surveillance standard are inadequate for its purpose;
• A substantial number of Standards being in "draft" form;
• A lack of specialist diagnostic expertise for avian diseases within the diagnostic laboratories;
• Difficulties in recruiting specialist diagnostic microbiologists, particularly at AHRL.

Performance:

• There have not been any recent detections of "serious" unwanted organisms new to New Zealand in farmed livestock or other domesticate animals and the probability of incursions of such diseases is low;
• Evidence that the system has potential for detecting new organisms comes from the number of reports of suspect exotic disease investigated by the NCDI (One case each of suspect Salmonella Dublin, Ehrlichia canis, TSE, Brucella canis, Dirofilaria immitis and Brucella abortus and two cases each of suspect vesicular disease, Equine Viral Arteritis and Anthrax and three cases of suspect exotic ticks during the last quarter of 2001 [102];
• The incident, in the late 2001, in which Mycoplasma mycoides mycoides (Large colony) was treated as a new incursion, when in fact subsequent investigations indicated it had probably been present and may have been recognised 10 years previously, illustrated the value of having a readily accessible and comprehensive information base on the existence of diseases and disease-causing organisms in New Zealand;
• Historically, passive Surveillance activities, generally comparable to the current laboratory based Surveillance programme, have led to the initial recognition, further definition and subsequent control of many infectious and non-infectious diseases in New Zealand;
• More recent examples of detection of disease-related organisms have included: _ Equine viral arteritis (which has been controlled); _ Trichinella spiralis (which remains endemic, probably in rats); _ Caprine arthritis encephalitis virus (which remains endemic but has been eradicated from a significant number of goat flocks); _ Neosporum caninum abortions in cattle (which remains endemic); _ Rabbit calicivirus disease (which remains endemic, with the encouragement of farmers); _ Salmonella typhimurium 160 (previously recognised in humans and accepted as endemic), and; _ Mycoplasma mycoides mycoides (Large colony); _ Infectious bursal disease of poultry (for which industry mounted and eradication programme which is considered to be nearing completion);
• Infectious diseases which have been recognised and subsequently eradicated include: Sheep scab, Brucella abortus, Hydatids, Aujeszky's disease, Anthrax (last clinical case prior to 1952), Swine Fever, and Scrapie. _ With the exception of Swine Fever and Scrapie all these diseases were endemic in NZ prior to the commencement of the eradication programmes. _ Scrapie was detected in imported sheep in their early "post-quarantine" period. _ All other diseases listed were detected through Surveillance programmes which would be classified as "passive".
• Most of the diseases listed above were detected through examination of laboratory submissions. Several were identified only through in-depth investigation of syndromes of unknown aetiology. Control of many was achieved only through NZ based research following the recognition of the primary cause.

Page last updated: 16 October 2008