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WHAT IS THE EXTENT OF, AND EXPOSURE TO, THE HAZARD?

What leadership is being shown by the Department?

It has to be acknowledged that leptospirosis is endemic in the New Zealand environment and that it is unrealistic to expect the existence of the organism in farm and feral animals, in waterways that are used for recreational purposes and during other casual exposures to be eliminated in the foreseeable future. Leptospirosis is a serious illness in humans. It is preventable to an extent only, and therefore the emphasis must be on prompt effective treatment as well as prevention. The most important aspect is the necessity to establish an ongoing and worthwhile partnership between occupational health, human health, veterinary science, and the industry stakeholders.

The usual approach would be:

• The development of an overall strategy and operational components/projects in consultation with stakeholders;
• Making decisions on components/projects on the basis of good data and evidenced based solutions;
• Resourcing the projects with appropriate personnel, equipment and funds;
• Implementing the projects within the proposed timescales; and
• Auditing and monitoring progress with modification of subsequent stages if shown to be necessary or appropriate.

Most individuals and organisations consulted in the course of this project reported that the "Guidelines" had been reasonably well received and provided a good basis for a range of appropriate initiatives by employers and employees. However they need to be linked to actual reality in the field. The gap between what it is thought people should do, and what they do, is often vast.

The Department of Labour has actively initiated, facilitated and participated in meetings identifying research priorities. The Department is unable to contribute to the funding of research.

Since the publication of the "Guidelines" the Department of Labour has demonstrated a commitment to proactive intervention at a level commensurate with its ability to contribute.

A total of 210 Notices of Improvement (Formal and Advisory Notices) were issued between the beginning of 2000 and September 2005 relating to employees contracting leptospirosis. Before that date the Department was successful in taking two prosecutions and one is currently pending.

Research is needed to determine the full extent of the hazard. There are a number of questions which must be answered before the appropriate interventions can be focused.

The opportunity to obtain one complete and comprehensive dataset.

As noted elsewhere in the Report there are currently up to five streams of incidence reporting of the infection (i.e. notifications by GPs, laboratory data, entries lodged by various parties in the Notifiable Occupational Disease System (NODS), ACC, and Meat Industry databases) which are not fully integrated.

Many people who have had close associations with the disease are convinced that there is considerable under reporting - anywhere between two and ten-fold. Hawaiian data cited showed that when comprehensive testing was done in that survey the actual level of incidence was some 600% greater than expected, or reported. 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.

The proposed Public Health Bill, scheduled for consideration at the Select Committee stages later this year, is intended to provide a frame work for managing public health risks that, in some circumstances, are unpredictable.

"The new legislative framework will cover the identification, assessment, and management of risks to public health. The Bill will focus on communicable disease and environmental health, and also provide a framework for dealing with current and future risks to public health not managed adequately under other legislation." (Proposed Public Health Bill - Background on www.moh.govt.nz ).

While leptospirosis is not a communicable disease in the normal human to human situation, it will be important for the Department of Labour and ACC to liaise with the Ministry of Health and other relevant agencies to see if the new legislation will provide the opportunity for the comprehensive collection and reporting of leptospirosis data and how this can be achieved in an accurate, complete, and timely manner.

The opportunity to obtain comprehensive regional data

The proposals for the monitoring of bloods of workers in meat plants (hopefully to be commenced within the next 3 months) will provide useful data on the extent of seroconversion in those individuals over time and enable the reporting of leptospirosis on the basis of antibodies in the blood rather than people who are diagnosed as being "sick". An important aspect from the results will be information on the seasonality of occurrence.

Additionally the three important short-term research priorities identified by the group in August 2004 are particularly relevant:

1. What is the "true" incidence of the infection, based on the linking of data from multiple sources?
2. What are the sources of human infection? What proportion of human leptospirosis is due to sheep and other livestock? Who is exposed? Which meat handling practices contribute?
3. What is the impact of leptospirosis on individuals and society? Can this be partly ameliorated by improved recognition and early treatment of cases?

Research carried out and reported since the publication of the Guidelines has confirmed the widespread incidence of leptospirosis in deer (83% of herds) and that there are levels of infection in sheep, especially in hoggets and mature ewes such that workers in sheep only plants are exposed to the risk when processing these animals.

However more research is needed to quantify the extent of infection in sheep flocks, and to obtain more data on the efficacy, and production benefits, of vaccination programmes in beef cattle and deer and the impact of those programmes on levels of infection in sheep on the same farms.

This information is required to persuade and convince beef, sheep, and deer farmers of the need for, efficacy, and benefit of, these programmes - with respect to both the cost and labour requirements, for undertaking such a vaccination programme.

Useful proposals are being worked on by researchers at Massey University Institute of Veterinary, Animal and Biomedical Sciences and the Department of Public Health, Wellington School of Medicine and Health Sciences in consultation with key stakeholders. In the period since the publication of the Guidelines difficulties have been experienced in obtaining funding for research proposals which have been formulated.

A Pilot Project in Hawkes Bay

The Hawkes Bay and Tairawhiti District Health Boards have consistently high rates (11.6 and 14.4/100,000 respectively) of incidence of leptospirosis (Baker 2004).

Hawkes Bay regional staff of the Department of Labour, the Medical Officer of Health, specialist occupational medicine physicians, organisers of the New Zealand Meat Workers Union, managers of meat processing plants, veterinarians and members of Federated Farmers and Rural Women have expressed strong interest in participating in a research project centred on that region.

The project would gather information on the incidence of leptospirosis in members of the farming community as well as the urban communities, explore links between the degree of infection in the various animal species (and by what serovars), with the exposure and incidence in humans. It would explore options of how knowledge of the disease status of animals could affect processes at the meat processing works. The efficacy and economics of the selected vaccination of different animal species could be researched, in combination with proposals being developed by Massey University.

Information gained on how members of the farming community view the disease and their reaction to possible measures to reduce its incidence could be very useful for the development of future strategies. The experiences of and attitudes to leptospirosis by members of the community could be ascertained in combination with proposals from the researchers at the Wellington Medical School.

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