Pied piper at the docks

Roy Kaye has a mission. As Chief Health Inspector at the port of Hull, he is resolved to prevent the plague-spreading black rat colonising Britain. But he may be too late, says Malcolm Smith

ROY KAYE thought he had seen the last of them. That was before the MV Sijanie - a Russian fish factory ship known as a Klondiker - docked at the Port of Hull very late one April night in 1992.

When Mr Kaye, the port's Chief Health Inspector, and his staff boarded the Sijanie to inspect her, they were shocked. Apart from its poor physical condition (Klondikers are notoriously more like rusted hulks than seagoing ships), the inside was dirty and crawling with cockroaches. But, far worse, it was overrun with rats - the plague-spreading black or ship rats.

Because of both its state of repair and construction, the MV Sijanie could not be fumigated. Nine days of baiting with poison and spraying produced 76 dead rats. The crew found yet more.

The MV Sijanie proved to be far from an isolated incident. "Last year, and so far this year," says Mr Kaye, "we found ship rats on 17 vessels, all of them Russian, mostly Klondikers. We have more than 9,000 ships arriving in the Port of Hull every year and we inspect around 40 per cent of them under health requirements. Anything suspect we inspect," he adds.

But it isn't only Roy Kaye who is concerned at the possible resurgence in Britain of the ship or black rat, Rattus rattus. Unlike its similar cousin, the brown rat, Rattus norvegicus, the black rat was thought to be on the verge of extinction in Britain. Its fortunes appear to have changed.

Britain is becoming, if not more rat-friendly, then clearly more rat- tolerant. According to a survey of nearly 11,000 homes, businesses and farms carried out last year by the Chartered Institute of Environmental Health and the Ministry of Agriculture, Food and Fisheries, rat infestations have risen by 40 per cent since 1979. These are nearly all the much commoner brown rat. Regionally, the eastern part of England is the most rat-infested, followed by North Wales and the south-west of England.

Distinguishing a black rat from a brown rat sounds easy enough. It isn't - because some brown rats are black while a few black rats are brown. Blacks are smaller (612in to 9in in head and body compared with the 8in to l012in of the brown) and their tails are longer and thinner. "In the hand," as one textbook blithely puts it, the black rat's ears are almost hairless. So if you care to handle a brown rat, you will notice its very furry ears!

Neither rat is native to Britain but the black rat is the longer established by many centuries. After the brown rat first arrived in England in the late 1720s, the black rat was, for some time, referred to as the "Old English" rat to differentiate it from the brash newcomer. For many years the black rat was believed to have hitched a lift to Britain in the baggage of returning Crusaders in the 12th century. But the discovery of black rat bones in second-century remains in York has given it far older English credentials.

Evidence for its existence over the next few centuries is sporadic, but by the 14th century "rattes" or "ratouns" were widely distributed in England and across Europe. In his Pardoner's Tale, Chaucer (1340-1400) tells of a citizen who:

"Forth he goeth, no lenger wold he tary,

Into the town unto a Pothecary,

And praied him that he him wolde sell

Som poison, that he might his ratouns quell".

There are numerous accounts throughout the Middle Ages of rat catchers trying to rid English villages of the vermin to protect stores of grain, butter and cheese. But what the rat catcher couldn't achieve, the brown rat did. More aggressive and adaptable, sturdy enough to breed outdoors in burrows, the brown rat quickly ousted its rival. The black rat went into slow decline.

By the Second World War it was still fairly common in London, a few inland towns and all our main ports; in the early 1950s a survey recorded it at 48 localities. From then until the mid-1980s, numbers fell, according to Dr Graham Twigg, an expert on the black rat and plague based at Royal Holloway and Bedford New Colleges in London. Documenting the black rat's decline, he attributes it to fewer rats arriving by ship at British ports because of their (generally) higher standard of hygiene, the re-development of old dockside buildings, new buildings made of concrete, the closure of many docks and a reduction in the quantity of goods carried on inland waterways.

But over the past decade, fortune has favoured the black rat. Although its present populations may be small, Dr Twigg's survey has recorded it in increasing numbers at 23 locations from Edinburgh to Tilbury. It is even present in Liverpool city centre, where it is occasionally found around shop loading-bays.

It is within this context that the more recent reports of infested ships at Hull, Tilbury, Truro and Falmouth give rise to concern. Port authorities are taking action. "Twelve-inch diameter metal discs are put on all mooring ropes if the ships have rats or if they look doubtful," says Roy Kaye at the Port of Hull. Adept climbers and high-wire artists, black rats can easily otherwise negotiate their way along plain mooring ropes. They also come ashore with cargoes; and possibly even swim for it.

Under the Public Health (Ships) Regul-ations, 1979, a Port Health Authority can insist on surveying a docked ship and on appropriate rat-control measures before a De-ratting Certificate is issued. But it's impossible to search each and every ship.

Increasingly, rather than coming by ship, cargoes are hauled by lorry from western and eastern Europe, and from the Middle East, and moved direct from ferry ports to distribution centres throughout Britain. Channel tunnel lorry traffic will add to this. Stowaway black rats could thus arrive in a multitude of inland locations that were previously beyond their reach.

Graham Twigg believes the very existence of a direct link between Britain and the Continent increases the chances of black rat arrivals, although the tunnel is equipped with barriers against unwelcome wildlife. "The twin tunnels have two high voltage grids, one about three kilometres from the French portals, the other nine kilometres from the English portal," says a Eurotunnel spokesman. "Like electric cattle fencing, they are designed to deter any animal." The grids are wrapped across the floor, up the tunnel sides and over the roof. But there are two gaps in each grid, one for each rail of the track to run through.

Rats are canny and agile creatures. They can climb vertical walls and even run along telegraph wires, so walking along a few feet of fixed metal rail until they pass the electric grids, they can probably manage on one leg. Provided they care to travel the 50 kilometres of tunnel. "So far," says the Eurotunnel spokesman, "none of the bait we put down in the tunnel, and regularly check, has been touched."

Eurotunnel, Klondikers and increased lorry cargoes apart, it is rising temperatures that may provide black rats with their biggest chance yet. "They might well find conditions out of doors favourable enough for breeding," says Graham Twigg. "A population has survived outdoors for many years on Lundy Island. It would not take much of a warming to release the black rat from its dependence on buildings, at least throughout southern Britain. Then, it would be much more difficult to control."

But do black rats actually pose such a health hazard? While bubonic plague is the well known example - and last year's much-debated outbreak in Gujarat has increased international vigilance - not all experts accept that the great plagues of Middle Ages Europe were, in fact, this disease. Dr Twigg himself, in his book The Black Death: a Biological Reappraisal (Batsford 1984), argues that other deadly infections, not all rat-borne, such as anthrax, may have played their part. None the less, plague is still very common in many parts of the world and rats are responsible for its spread.

Black rats - like many rodents - are prolific disease-carriers. They can be hearth and home to the flea-borne murine typhus, mite-borne scrub typhus and to the bacteria that frequently contaminate rat urine, causing lepstospirosis (or Weil's disease) in humans, who can contract it from contaminated water. Add to these salmonella food-poisoning caused by rat droppings contaminating food, toxoplasmosis, to which pregnant women are particularly vulnerable, and a number of other warmer climate diseases such as leishmaniasis, and it is obvious that black rat - though no worse than many other rodents - is not the key to a healthier life.

The last reported case of plague in Hull was in 1916, the victim a workman repairing an Egyptian vessel. Roy Kaye may not see himself as a latter- day Pied Piper but he is as determined as the townsfolk of 13th-century Hamelin to do away with any black rats. !