Protecting people at work who have an elevated risk of exposure to leptospirosis will be required by law in almost every country, and should begin with removal of the hazard (where possible) followed by protective equipment. It is not possible at this time to protect employees by giving them medication or vaccination.
Note for European workplaces
Leptospira interrogans is a class 2 pathogen under EU Directive 93/88/EEC, and where it is being used as part of research, appropriate containment measures must be enforced. However, as there is no human vaccine, the requirements of Article 14(3) do not apply.
When exposure to the “wild” bacterial population is incidental to a workplace task, measures to limit the risk to employees are still required, however it is clearly not possible to enforce laboratory-type containment and barrier systems, and as the bacteria are not packaged as ‘a product’ there will be no material data safety sheets, labelling or transport rules to follow.
Hazard removal
In simple terms, where the bacteria can be eliminated from a workplace they should be – so for example pest control and building hygiene are important first steps. This is often difficult where the workplace cannot be controlled (e.g. on construction sites) but measures should be put in place to at least protect eating areas and water supplies. Where the work itself involves exposure to the bacteria, staff education is paramount. Facilities should be on hand to allow workers to disinfect their skin should they be accidentally exposed, and advice given on the reasons for infection, the symptoms to look out for and what action to take should an accident occur.
High-risk occupations in this category include but are not limited to:-
- Veterinary medicine
- Livestock handling, slaughter and meat production
- Farming involving immersion in water (rice farming, aquaculture, etc.)
- Farming in areas of high carrier host activity (sugar cane plantations, etc.)
- Leading and instructing adventure sports such as caving, rafting, kayaking, trekking, etc.)
- Manual work in the wastewater industry
- Pest control involving any carrier species (not just rats)
- Work in underground confined spaces (tunnels, mines, etc. with a wild mammal presence)
Even if the environment remains contaminated, it is often possible to isolate workers from the hazard by adopting remote-reach equipment or designing activities to prevent the risks of falling into water, for example by using long-handled tools or guard-rail barriers when taking water samples.
Personal protective equipment
For general activities, protection of broken skin using waterproof dressings or clothing is the most important factor, but where there is a risk of aerosol spray (for example when pressure-washing or performing veterinary or meat preparation tasks) then eye and face protection is advised to prevent liquid droplets from entering the mouth or eyes. Goggles and a simple paper dustmask will be adequate in most cases. Clothing will be non-infectious once dried and washed, so full coveralls are not essential unless there are associated hazards that demand them. Workers should be given facilities to wash their hands, including soap or antibacterial gel, so they can remove any contaminant from their skin after an accidental exposure.
For situations where workers may accidentally immerse themselves (by falling into water) there is no reasonable way to prevent them inhaling and ingesting some water, so protective measures should be used to prevent the fall in the first place – barriers, covers or fall protection harnesses. It is important to remember that water which is likely to contain leptospira is equally likely to contain many other harmful bacteria, viruses or chemicals.
Commercial diving operations
Diving in the workplace, in freshwater sites, is of course a guaranteed method of total immersion and the risks must be assessed in detail. Basic open-circuit scuba with a mouthpiece regulator is not suitable as there will be water ingestion, so full-face masks or ‘hard hat’ diving are required. Drysuits are not completely essential if the diver’s skin is entirely undamaged, but are usually worn as standard and we advise they be used. There is an extremely small risk of venereal infection via the genital tract if immersed using a wetsuit, and as yet the potential for leptospires to burrow through very waterlogged skin has not been ruled out. Equipment should be washed after use and allowed to completely dry for at least one hour, alternately it can be immersed in disinfectant solution or seawater and soaked for five minutes.