| Something
crept into my bedroom the other night. It rustled a discarded
crisp packet and sent my wife scurrying for the safety of the
children’s beds. They, at least, were two feet off the floor.
I slept on uneasily, conscious that only three inches of futon
separated me from the scavenging mouse.
Ours was an all-too-frequent visitor to British homes.
Roughly one in 20 households were believed to harbour mice when
the last comprehensive survey was undertaken in the Seventies.
More recent reports suggest that rodents, particularly rats, are
on the increase. A definitive answer will soon be with us,
courtesy of the National Rodent Survey. Fifteen months of
peering into the nation’s larders came to an end last
December, and the results are expected this month.
"the sweet and depressing smell that signals a mouse’s
territory"
The environmental health officers who are conducting the
survey will be looking for exactly the kind of evidence that we
found the morning after our nocturnal visit. Mice leave about 80 droppings a day. These rice-grain-sized black spindles
were spread around the house, often accompanied by the sweet and
depressing smell that signals a mouse’s territory.
Rats and mice owe their success to an astonishing fecundity
– a breeding pair of mice can generate 2,000 offspring
in a year – and to man’s propensity to dump refuse on
his own doorstep. Not until the introduction of efficient public
sanitation were the plagues of rats that besieged earlier
generations eradicated. Ironically, it is those same sewers that
now harbour the rodent population. Constant vigilance is
required to keep numbers in check, yet the water authorities who
are responsible are regularly accused of cutting funds for sewer
baiting.
Rodents present a serious public health risk. Rats are still
recognised carriers of bubonic plague and were responsible for
an outbreak during the Vietnam War. The last British case of
plague was in the early 1900s. Another potentially fatal and
increasingly common health problem is Weil’s disease. Water
sports enthusiasts are particularly at risk since the bacteria
responsible find their way into water via rat urine.
"the chemical industry has adapted to delivering
death with a smile"
Rats and mice carry other diseases such as murine typhus, are
major destroyers and contaminators of food, and rats have been known
to attack children. They also take great pride in their teeth,
gnawing continually to keep them short and sharp. When gas pipes
and electric cables are involved the consequences can be
disastrous. The arguments for reducing rodent numbers are
strong.
When all else fails we resort to chemicals. Rodent pesticides
are not permitted to cause pain or suffering, so the chemical
industry has adapted to delivering death with a smile. The most
common of these gentle killers are anticoagulant poisons. The
first generation of anticoagulants worked well until the targets
became resistant to them.
This development resulted in a host of newspaper headlines
proclaiming the arrival of Super Rat and the demise of
civilisation. In the event, civilisation scraped through, but
resistance became so widespread that a second generation of
anticoagulants was introduced. Can we expect to see resistance
developing again? Peter Bateman of Rentokil believes so.
"Though still rare, Super Rat Mark II is already with
us," he claims.
The onward march of rodent populations has been well
documented by the press. In 1989, the Institution of
Environmental Health Officers published a report claiming that
rat numbers in England and Wales had increased by 20 per cent.
Various explanations were offered: a succession of mild winters,
cutbacks in the funding for environmental health departments,
changes in agricultural methods, and increased levels of urban
refuse and litter.
Two groups came in for particular criticism: the water
authorities for giving a low priority to sewer baiting, and
British Rail for an unwillingness to clean up its property or
co-operate with local pest control officers.
So what is happening to rodent numbers in the Nineties? The
co-ordinator of the National Rodent Survey, Dr Adrian Meyer, of
the government’s Central Science Laboratory, says: "Scare
stories appear periodically, but nobody knows what the real
situation is."
"rodent populations rise and fall under the influence of
many factors"
Rodent surveys that rely purely on reported infestations are
known to be unreliable in London, where fewer than 10 per cent of
mouse and less than 30 per cent of rat infestations are reported
to local authorities. The National Rodent Survey looks instead
at households selected at random from Council Tax registers.
This allows a direct comparison with a similar survey conducted
during the Seventies. In addition, the survey will identify
differing treatment methods and highlight regional variations in
the allocation of responsibility for rodent control.
The headline numbers may not mean much in themselves. Rodent
populations rise and fall under the influence of many factors,
the greatest of which is the weather. Cold winters reduce the
population, mild ones bring rapid increases.
Another round of shock newspaper stories will at least
concentrate minds on rodents. If that unlocks funding for
prevention and persuades the nation to change its habits, the
survey will have done a worthy job. As Jackie Marsh of the
Institution of Environmental Health Officers says,
"Everyone has a double responsibility: to take care not to
encourage rodents and to report infestations immediately." |
