Explainer | Smelling a rat: what is Hong Kong’s rodent infestation rate and why is it under fire?
- Current methodology for determining rate has ‘insufficiencies’, Deputy Chief Secretary for Administration Warner Cheuk says
- Over the years, critics have said index does not accurately reflect severity of city’s rat problem
Hong Kong’s rodent infestation rate has been a key indicator measuring the extent of the city’s rat problem for more than two decades, but it has recently been singled out for reform by Deputy Chief Secretary for Administration Warner Cheuk Wing-hing.
The Post examines the index and why it is in the crosshairs of officials in charge of the city’s latest clean-up campaign.
1. What is the rodent infestation rate?
The figure measures the presence of rats in a particular area. It is based on the findings of the Food and Environmental Hygiene Department’s rodent infestation survey and is calculated by dividing the number of pieces of bait consumed by the animal with the amount of bait collected from a survey location. District and citywide figures are also available.
The department has carried out the study regularly since 2000. It currently covers a total of 50 locations across 19 districts. These spots are either rodent-infested areas or places that are likely to suffer from the issue.
As part of the study, authorities use a piece of uncooked sweet potato as bait since it is “generally attractive” to rodents and will leave clear marks from the animals.
2. Why is there renewed interest in the rate?
Deputy Chief Secretary Warner Cheuk on Saturday said the current rodent infestation rate had “insufficiencies”, raising the example of using sweet potatoes as bait.
“The rate will be low naturally when the rats don’t even come to bite the sweet potato,” Cheuk said, adding the indicator needed to be reformed and that authorities were working with the University of Hong Kong to develop a new, more comprehensive way of assessing the rat population.