Areas of rural and regional NSW are currently affected by an ongoing mouse plague which may increase health and safety risks for those in contact with rodents – particularly farmers and agriculture workers.
These risks include greater exposure to diseases such as leptospirosis and hazardous chemicals like zinc phosphide. Your mental health and wellbeing and that of your colleagues and workers could also be impacted.
The following information explains the health and safety risks in more detail and provides guidance and resources for employers and workers to manage the increased risks as well as help your workplace stay healthy and safe as we combat the mouse plague.
Exposure to diseases
Zoonoses such as leptospirosis are diseases that can be transmitted between animals and humans. Leptospirosis is a bacterial infection that can be spread from animals, such as rodents to people. Exposure can occur through contact with infected mice or water, soil or mud that has been contaminated by the urine of infected mice. The bacteria can enter the human body through cuts or abrasions and occasionally through the lining of the mouth, nose and eyes.
Rodents such as mice can also transmit other diseases to humans, including lymphocytic choriomeningitis virus (LCMV), rat bite fever and gastrointestinal infections such as salmonellosis.
Who is at risk?
You are at risk of exposure to leptospirosis if you have close contact with rodents and other infected animals or are exposed to water, mud, soil or vegetation that has been contaminated with infected urine.
Farmers, agriculture, horticulture and abattoir workers are some groups who are at higher risk of exposure. Rainfall and flooding events such as those recently seen across NSW can also increase the risk of leptospirosis.
Symptoms and treatment
Symptoms of leptospirosis usually develop within five to 14 days after infection.
Symptoms may include flu-like symptoms such as headaches, muscle aches, fever, chills, vomiting, diarrhoea and conjunctivitis. Some people will only have mild symptoms, although some may develop severe disease including kidney and liver problems, jaundice, bleeding and lung problems.
If you have symptoms that might be due to leptospirosis, it is important to see a doctor as soon as possible. Diagnosis can be made using blood tests and is treated with antibiotics. Antibiotics are more effective when started early in the disease.
Leptospirosis is considered a serious illness under the Work Health and Safety Act. All cases of leptospirosis acquired in the workplace must be reported to SafeWork NSW on 13 10 50.
Control measures – what you can do
There are a number of ways to minimise the risk of leptospirosis exposure in your workplace.
Minimise rodent contact
- Clean-up rubbish and remove food sources around your workplace or onsite accommodation.
- Seal as many holes or gaps as possible inside your premises.
- Conduct regular pest control such as baiting and traps. Do not set traps near food preparation areas.
When you work in areas where mice and rodents have been
- Cover cuts and abrasions with a waterproof dressing.
- Wear personal protective equipment (PPE), including gloves and waterproof protective clothing (for example, goggles, aprons and boots) where contact with rodents or their urine is possible (such as clean-up of mouse carcasses). Handling of rodent carcasses should not be undertaken by workers who are pregnant or whose immune system is suppressed.
- Wear appropriate footwear when walking in mud or moist soil.
- Avoid wading in or drinking water that could contain rodent urine (boil drinking water if you are unsure).
- Wash any cuts and scratches sustained immediately with clean water and soap.
- Wash hands with clean water and soap and dry thoroughly after handling potentially infected material – especially before eating, drinking or smoking.
- Shower after work.
Clean and decontaminate
- Clean and disinfect rodent contact areas such as floors and countertops with disinfectant or bleach solution.
- Wash any clothing or bedding with laundry detergent in hot water if exposed to rodent urine or droppings.
- SafeWork NSW - Leptospirosis webpage
- SafeWork NSW - Leptospirosis fact sheet (PDF 203kb)
- NSW Health – Staying healthy during a mouse plague fact sheet
- EPA Factsheet – Guidance on the handling and disposal of dead mice (PDF 224kb)
Managing Hazardous Chemicals - Zinc phosphide
To control the mice population, farmers and workers may use hazardous chemicals such as zinc phosphide more often and in bigger quantities than commonly used in mouse and rat baits.
The Australian Pesticides and Veterinary Medicines Authority (APVMA) has recently issued a permit allowing the concentration of zinc phosphide to be increased from 25 grams per kilogram to 50 grams per kilogram in mouse and rat baits.
Exposure and symptoms
Exposure to zinc phosphide can be hazardous to your health. Exposure can occur by getting it on your skin, breathing it in or accidently eating or drinking a product containing the chemical. When zinc phosphide is accidently eaten by a person it can travel to the stomach and mix with stomach acid – causing it to release the toxic gas, phosphine.
Symptoms of exposure to zinc phosphide include headaches, dizziness, vomiting and difficulty breathing. It can also cause liver and kidney failure, convulsions, delirium, coma and death in cases with severe acute exposure.
Zinc phosphide is a hazardous chemical, so it is important to use, handle, store and dispose of it safely.
Ask your supplier for safety data sheets (SDS) and always refer to product labels and the SDS for directions on the safe use, handling, storage and disposal of hazardous chemicals. Read and understand the health effects of the product that you are using and note the safety measures required to use the chemical safely.
- Follow instructions and information in labels and the SDS for safe use.
- Ensure all workers and others who are handling the chemical are informed of the risks to their health and are instructed on working safely with it.
- Do not open zinc phosphide in enclosed areas and avoid inhaling any vapour.
- Make sure correct personal protective equipment (PPE) such as gloves, masks (with suitable gas filter cartridges) and protective clothing are used and provided to those who are at risk of exposure.
- Make sure you practice good personal hygiene to reduce your risk of exposure.
- Always remove contaminated clothing and wash hands after using chemicals and before eating, drinking, using the toilet or smoking
- Wash contaminated clothing separately.
- Follow instructions and information in labels and the SDS for safe handling.
- Read APVMA labels, follow instructions and use mouse bait products at approved doses.
- Display appropriate warning signs where necessary to warn others and prevent entry into zinc phosphide application areas..
Storage and disposal
- Follow instructions and information in the SDS for safe storage and disposal.
- Store the chemical in a ventilated, secure place that is away from children, animals, food, seed and fertiliser.
- Keep zinc phosphide away from acids and ignition sources
In case of accidental release, follow the emergency procedures provided in the SDS. If you are worried about any possible health effects from using zinc phosphide, talk to your doctor.
- Department of Primary Industries – Mouse management
- NSW Environment Protection Authority – Misuse of mouse baits leads to poisoning
- SafeWork NSW Code of Practice – Managing risks of hazardous chemicals in the workplace
Rebates and financial support package
The NSW government is offering financial support to help manage the costs of baiting in rural and regional NSW to combat the mouse plague.
The NSW mouse control rebate, includes rebates of up to $1,000 for mouse baits, traps and cleaning materials for eligible small businesses including primary producers and sole traders and up to $500 for households. This rebate is available through Service NSW.
Primary producers will be able to claim a rebate for buying zinc phosphide ahead of spring.
Learn more about the government's financial support package.
Mental health matters
Your wellbeing and that of your workers and colleagues can be impacted during challenging times. You don’t need to be a mental health expert to provide and seek support.
You can show that mental health and workplace safety is a priority in the workplace by supporting your team and leading change. Support is available from the Rural Adversity Mental Health Program (RAMHP) and the Centre for Rural and Remote Mental Health (CRRMH).
We also have some useful information and resources on mental health at work during the COVID-19 pandemic.
Call one of these crisis support services or go to their website for online chat options:
- Lifeline Australia – 13 11 14
- Kids Helpline (for under 25’s) – 1800 55 1800
- MensLine Australia – 1300 78 99 78
- Suicide Call Back Service – 1300 659 467
- Beyondblue – 1300 22 4636
For connection to specialist mental health services, call 1800 011 511.
In an emergency call 000 or go to your nearest Emergency Department.