The Western Australian College of Agriculture at Morawa has been closed and students sent home until further notice after a toxic mouse bait only approved for grain paddocks was spread on its campus.
A severe mouse plague has overwhelmed Morawa, 370 kilometres north of Perth, with rodents invading homes, businesses and paddocks in this Wheatbelt town.
Farmers have been spreading mouse baits containing zinc phosphide, a schedule 7 poison, on their paddocks for weeks, but these baits are not approved for use in towns, residential areas or around buildings due to their toxicity.
Dead mice can be found all throughout the town of Morawa. (ABC Midwest and Wheatbelt: Chris Lewis)
“During the management of the mouse infestation a product called Mouse Off was used at the school site,” the school principal said in a letter to parents and staff.
Mouse Off is the commercial name for the zinc phosphide bait.
Double strength mouse bait is thought to be most effective controlling mice in a plague. (ABC Mid West Wheatbelt: Chris Lewis)
“To ensure the wellbeing of all students and staff, the department [of Education] will undertake a deep clean of all affected areas.”
The school will advise when it would reopen after the clean up was completed, the letter said.
Parents of the students who board at the school had been advised to collect their children or alternative arrangements would be made to accommodate them at another residential college.
Working farm
The agricultural college has about 50 students in years 10, 11 and 12.
It includes a 3,000 hectare working broadacre and livestock farm, where students learn practical knowledge of modern farming.
The Department of Health said that based on the information available so far, the risk to staff and students at the school is low.
“We are continuing to work with education staff to provide support,” it added in a statement.
All students and staff had been sent home and horses were moved to agistment off site, the school said.
Mouse bait permitted to be spread on paddocks is wheat treated with the poison zinc phosphide. (ABC Mid West Wheatbelt: Chris Lewis)
The Department of Education said the school had been closed ‘due to the management of a mouse infestation’.
“To ensure the health and wellbeing of all students and staff, the Department is undertaking a thorough deep clean of all affected areas,” the statement said.
“Arrangements were made for students remaining in Morawa to attend Morawa District High School during the closure.”
Risk to human health
The Australian Pesticides and Veterinary Medicines Authority (APVMA) does not approve the use of products containing zinc phosphide in enclosed environments as phosphine gas can be released when the bait becomes wet.
Exposure to zinc phosphide can make people unwell and in high levels can be fatal.
Mice are everywhere in Morawa. (ABC Midwest and Wheatbelt: Chris Lewis)
Last week, officials from the WA Department of Health visited Morawa after community leaders raised concerns the number of dead and dying rodents in the town could lead to some sort of health related outbreak.
Earlier this week the APVMA conditionally approved an emergency permit for the manufacture and dispersal of double-strength zinc phosphide mouse baits.
This bait began arriving on farms this week.
