The recent deaths of three people from an apparent outbreak of a rodent-borne virus on a cruise ship make one thing clear: Rats near your home or place of work pose a deadly risk.
The hantavirus is found and transmitted worldwide wherever mice, rats or other rodents are present and can cause fever and severe respiratory illness in humans. Infection typically occurs through exposure to the urine, droppings or saliva of infected rodents.
So what can you do if you spot rats on your own property?
There is no quick answer, but it can help to first ask yourself: Why are the rats here? The answer often lies in human behaviour - or more precisely, in the fact that the rodents are finding enough to eat nearby.
"In most cases, the cause is food sources such as food scraps on the compost, open rubbish storage, pet or livestock feed accessible to rats, bird or hedgehog feeding stations, or food waste illegally disposed of via the sewage system," says Julian Heiermann, an environmental specialist at Germany's Nature and Biodiversity Conservation Union (NABU).
To avoid attracting rats in the first place, you should never throw food scraps down the toilet - and ideally not onto the garden compost either. If you keep rabbits or chickens, you should also take care that no leftover feed is left lying around, experts say.
Bird feeding in the garden poses a similar problem. According to Heiermann, it is "difficult to impossible to offer bird food in a way that rats cannot benefit from it, because something can always fall to the ground - and rats are also very good at climbing and jumping." Balconies that are inaccessible to rats are an exception.
But what if you do not have a balcony and do not want to give up feeding birds? "A hanging feeder fitted with a tray to catch falling bird food would be the best option," says Heiermann.
Storing junk and waste on a property also encourages rats to settle there, environmental experts say, as it provides undisturbed nesting sites.
The problem is that individuals often have little influence over what food scraps and rubbish end up in shared courtyards and streets. Heiermann recommends talking to neighbours if rats are becoming a risk.
Environmental experts advise against using mechanical traps, since common rats are difficult to catch with them, and depending on the type of trap, the high impact force poses a risk of injury to children and pets.
Heiermann also suggests avoiding traps: "If you only use traps or poison, this does nothing to address the root cause, it does not do justice to the animals and you have to expect that you will continue to have a 'rat problem', since rats have a high reproduction rate - or simply new rats will move in."
The use of rat poison is also subject to regulations in many places, since there is a risk that domestic and wild animals will unintentionally be killed.
There are a few simple measures that can help prevent rats from getting from the property into the house, for example special backflow valves designed to stop rats entering drainpipes. Window openings can also be secured with grilles, while gaps in the frames of doors and gates can be blocked with brush strips.
What about devices sold in DIY stores that claim to repel rats using ultrasonic signals? The initial consensus is that they have proven ineffective, and Germany's Federal Environment Agency says they neither keep nor drive rats away.
If rats simply will not go away and end up inside the home as well as outside, the most sensible course of action is to seek professional help - for example from professional pest controllers, or from the local health authority if property management companies fail to act.
The WHO wrote on X in May that at least one of three deaths on a cruise ship in the Atlantic was confirmed in a laboratory as hantavirus, while the remaining infections are still classified as suspected. – dpa
