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EXECUTIVE SUMMARY

It is extremely unlikely that Leptospirosis will be eliminated entirely from the New Zealand environment. There is no human vaccine. Therefore the emphasis must be to isolate and minimise the hazard. There is no human to human transmission.

Key stakeholders are the Department of Labour (DOL), the Accident Compensation Corporation (ACC), Ministry of Health (MoH), meat industry, meat workers unions, farmers and their families, general practitioners, animal researchers, public health researchers, veterinarians, and animal vaccine manufacturers.

Following the publication of the "Guidelines" in 2001 there have been a range of initiatives taken by each of the main stakeholder groups as they have striven to meet their respective responsibilities. While this review has identified a number of specific areas requiring further research the key issue is how the contributions of the stakeholders can be brought together demonstrating the extent to which the industry has assumed responsibility for reducing the incidence and severity of occupationally acquired Leptospirosis in New Zealand, and how this leadership can be enhanced in the future.

The specific areas requiring further research are:

1. Definitive data on the occurrence of Leptospirosis in the community, especially the rural community.
2. Development of one comprehensive dataset rather than having to rely on the five different systems as at present.
3. Development of "easier-to-use" personal protective equipment of proven efficacy particularly for use in "high-at-risk" areas of meat processing plants.
4. The efficacy of vaccines for sheep and deer and hence the economics of use with these species.
5. Improvements in diagnostic tests for humans and the possibility of tests for animals before they are offered for sale or slaughter and processing.
6. Identification of sources of funding for related research initiatives.

In support of these areas and issues:

Occurrence of Leptospirosis in the community

Notified cases of leptospirosis in New Zealand increased in the period 1999 - 2002 in which year 140 cases were notified, and then have trended down with 86 and 89 notified cases in the years ended June 2005 and 2006 respectively.

Accurate information must be collected on the actual incidence of leptospirosis in rural and urban communities, the serovars involved, and the linking of this to exposures of people to various animal species, rodents and recreational waterways. Case report forms and procedures need to be amended accordingly. The absence of comprehensive and accurate data significantly inhibits the calculation of the total costs of leptospirosis and the hence the benefits and return on various preventive strategies.

It is widely believed that there is considerable underreporting of the disease. A comprehensive study in Hawaii indicated a 600% increase in actual incidence over reported "sickness". It is hoped that a study of seroconversion of meat workers to be conducted by Katie Owens of MAF and Massey University staff will be able to commence soon. A key feature will be the reporting of leptospirosis on the basis of antibodies in the blood rather than people being diagnosed as being "sick".

Cross sectional studies would provide very valuable information on levels of infection and the impacts in people, animals, and wildlife. The Hawkes Bay has been identified as an area where this type of research could take place, for a number of reasons.

Development of one comprehensive dataset

There are considerable differences in recording systems and processes. For ESR - laboratory confirmed tests greatly exceed the number of notifications through related health systems. There is a different number in the Notifiable Occupational Disease System (NODS) and the ACC and the meat industry databases. The Public Health Bill to be introduced sometime in the future might offer scope for rationalisation and a new start with one integrated and comprehensive system. It is recommended that this opportunity be pursued.

Development of "easier-to-use" personal protective equipment (PPE)

Most, if not all, meat processing companies have developed appropriate health and safety documentation and consulted with staff about its implementation and observance.

Adaptation of PPE to the particular circumstances of various workstations within the meat industry is ongoing. Operators report that with some equipment they experience significant limitations in comfort, visibility, and ease of use when worn for extended periods. Automation of the most "at risk" processes is highly unlikely.

Positive initiatives within meat processing plants include the wearing of cut-resistant gloves, the wearing of water proof gloves, the wearing of special protective glasses, the use of "Stonepine" cream, and the use of some face shields. Following the implementation of the Smokefree Act the limitation of smoking to specific designated areas is a positive move.

Efficacy of vaccines for sheep and deer

Since 2001 there has been an increase in workers in lamb only plants and deer slaughter premises contracting leptospirosis. It is noted that some works drawing stock from particular regions will have very little occurrence of leptospirosis while other plants drawing stock from the same areas can have a much higher incidence - this is an area warranting further study.

Staff at Massey University are seeking funding to research the production effect of leptospirosis in lambs, and older sheep, and the efficacy of vaccination in controlling leptospirosis at the sheep farm level. Alternatively will vaccination of all cattle and deer on the property significantly reduce the infection in sheep on that farm? All young animals are born seronegative therefore any seropositive animals have become infected during their lifetime.

Research reported in 2005 by staff from Massey University and Invermay indicates some 80% of deer herds have a high proportion of stock infected. Vaccination, by definition is meant to be the elimination of shedding in those animals not infected at the time of vaccination. Some productivity gains after vaccination have been reported in deer.

Improvements in diagnostic tests for humans and for animals before slaughter

Two blood tests, some 4 to 6 weeks apart, and using the microscopic agglutination test (MAT) are the primary method of diagnosing leptospirosis in humans. A 4 fold increase in titre is required to provide confirmation of a positive diagnosis. A polymerase chain reaction (PCR) test is available - the analysis of one sample providing a definitive diagnosis of the presence or absence of leptospirosis, but not of the serovar causing the infection.

There are numerous accounts of delays by both GPs and hospital clinicians in ordering tests, and also in employers being reluctant to meet the cost of either the MAT or the PCR tests. Simplified testing for humans would be particularly advantageous.

There is a need to develop simple, rapid tests to identify infected herds and flocks so that staff at the meat plants can be warned in advance.

Identification of sources of funding

While the DOL has actively initiated, facilitated and participated in meetings identifying research priorities and prevention strategies it does not have any appropriation to fund the research initiatives identified. Animal industry funding has supported projects carried out by Massey University veterinarians. Some funding for the research of the kind suggested might be possible from the joint Occupational Health Research Fund - now administered jointly by ACC and the Health Research Council and this and other possibilities need to be explored.

Other institutional and industry initiatives

Since the publication of the "Guidelines" the DOL has demonstrated a commitment to proactive intervention and enforcement commensurate with the severity of the other workplace health and safety matters it deals with. Some 210 improvement notices relating to leptospirosis and employees were issued between December 1999 and September 2005. Two prosecutions were taken before December 1999 and one is currently pending (2006).

The "Guidelines" published by the DOL in 2001 were reasonably well received - relevant parts were extracted by meat works, regional DOL offices, and industry groups and communicated to various audiences and target groups. Some updating and amendment, to correct current ambiguities, is required. It is recommended that the sections of the Guidelines which need change are identified and an updated version generated.

Although Leptospirosis was added to ACC's Schedule 2 in 1998 the percentage of "lodged claims" that have become "covered claims" has declined. It is hoped that the reasons for these trends can be explored.

Training of staff of the various stakeholders is ongoing. In a number of regions there has been good information for employees to share with doctors, information made available to GPs, and to farmers, their families, and people handling livestock. Additional strategies for communication to interested parties should be developed when the Guidelines are updated.

Progress with other species - cattle and pigs

Estimates are that some 90% of dairy cattle are vaccinated on an ongoing basis. The Westland Dairy Co has paid for the vaccination of dairy cattle owned and farmed by its suppliers since 1984. The NZVA wants to extend its prevention programme (called Leptosure TM) to 8000 dairy farms within 5 years. Very little data is available on the incidence of leptospirosis in dairy herds.

Previous work by Roger Marshall indicates a similar proportion (80%) of beef cattle herds are infected with leptospirosis.

Vaccination of all pigs for leptospirosis is encouraged and definitely improves productivity in sows, baconers, and porkers. Major pig processing companies will not accept stock from properties which cannot produce a vaccination certificate.

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