Rodent Damage

Problems caused by Rodents

Rodents can cause problems even if they are few in number. The following outlines some of the most common ones, but for many people just the knowledge that a mouse or a rat has come into their home needs addressing.


Pest rodents can chew through cables and electric wiring, causing fires and power outages. In 2014 a grade 2 listed farmhouse in England caught fire.

It took nearly 50 firemen, some of whom worked throughout the night, to put out the blaze. Rats chewing through electric wires were blamed.

Suncorp Group, one of Australian’s largest insurance groups, has paid out more than AU$3.5 million since 2011 due to rodent-related damage.

Some of the claims came from owners of cars that had their wiring damaged when rats took refuge under the warm hoods in cold weather and nibbled on anything nearby in the absence of food.

Population swarms

YouTube has disturbing videos of mice plagues, with millions of the vermin swarming on farms in Southern Australia. The direct costs of these plagues to the agricultural industry can be as high as AU$38 million, with indirect costs adding considerably more.

The situation has become sufficiently worrying in rural parts of the country that an official online mouse census is available, with plague threat warnings. This is not purely an Australian issue.

In Asia, it is estimated that the rice damaged by rats and mice in one year would feed approximately 200 million people, which is about 8 times the current population of Australia!

Both Sydney and Melbourne have suffered negative publicity due to rapidly increasing rat populations. In Melbourne, rats are brazenly sitting in the open in parks, even stealing food from possums in broad daylight to avoid poison bait left out by the authorities.


Rodents are, perhaps, most notorious for the diseases they spread. Worldwide they are known to be vectors of 35 diseases.

Of the two species of non-native rat in Australia, the black rat is the carrier of the most infamous in history: the Bubonic Plague or Black Death. Rat’s blood can carry many types of infectious bacteria with no harm to itself, which is what makes it so dangerous.

Diseases include:

  • Salmonellosis
  • Leptospirosis
  • Typhoid
  • Tularemia
  • Lymphocytic Choriomeningitis
  • Streptobacillus Moniliformis (Rat bite fever)


There are many more, some endemic to Australia. These can be caused by:

  • rodent urine or faeces contaminating food
  • rodents scratching or biting people
  • biting insects transferring disease from rodents to humans
  • bacterial infection.


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