Rats are a risk to health
Rat infestations are a serious health and safety concern. A rat-free environment is also a legal hygiene requirement for businesses (Health and Safety at Work Act (1974) and Food Safety Act (1990)): Rats and their urine can harbour Leptospirosis bacteria, amongst an array of other disease causing pathogens, causing Weil's disease in man. The illness caused by this bacterium can be fatally serious!
The presence of rats in hospitality and food related industries will cause loss of reputation, goodwill and revenue, in addition to the possibility of prosecutions and closure. Signs of rats and/or any problems with preventative rat control measures are likely to have have a negative impact on "scores on the doors" food hygiene ratings.
Rats can also cause structural damage, such as to the fabric of buildings and electrical wiring. This poses a serious fire hazard, which alone is reason enough to get rid of rats.
Brown (sewer) rat biology
Brown rat "Rattus norvegicus"
The brow rat (rattus norvegicus) is an rodent weighing between 200-500 grams with a heavy body (usually brown in colour), a tail shorter than its body and small ears. The preferred habitats of the brown rat are damp conditions and where water is present, such as river banks and streams, where it burrows several feet underground. Examples of these can be readily observed along the banks of the Leeds-Liverpool canal and the river Douglas flowing through Wigan.
Brown rats are also found in sewers and outdoor animal housing, but will readily move inside, especially during colder months. They can also be found in cellars and lofts.
The gestation period of rats is 21 days and they can have up to 6 litters a year with up to 8 pinkies per litter. This means that a single pair of rats, under favorable conditions, can produce up to 200 young a year! Therefore it is important that action is taken at the first signs of rats.
Brown rats should not be confused with Water voles (Arvicola terrestris) which are a bit smaller, have rounded noses and shorter tails. This species is protected under the Wildlife and Countryside Act 1981, and we always check for the presence of water voles near waterways before rat control commences.
All rat species use urine as a means of communication, and one sign of a heavy infestation is the presence of urine trails; grey-brown streaks where rats travel, 1-2 cm long sausage shaped droppings and a distinct ammonia-like odour caused by the breakdown of urine
The black (ship) rat
Black rat "Rattus rattus"
The black rat (Rattus rattus) is now relatively rare and is mainly associated with ports and ships or present in lofts. I have personally not seen any black rats in the Wigan, Bolton, Preston or Liverpool areas. Black rats are more slender than the brown rat, with the tail longer than the body, relatively large ears and eyes, and are excellent climbers. The black rat is associated with dry sheltered areas and is rarely found in sewers. It probably originated in South-East Asia. The black rat was probably a carrier of the rat flea, responsible for outbreaks of the bubonic plague in the middle ages.
Rat control in Wigan, Bolton, Preston, Liverpool and Manchester
An effective rat eradication programme starts with locating of droppings, identifying harbourage sites and identifying rat entry points for proofing. Food sources need to be removed or made inaccessible. Sewers are often points of entry, and these might need an internal inspection to detect defects. When carrying out rat baiting with rodenticides we always keep health and safety and the environment in mind and use sturdy, anchored, inaccessible bait boxes.
The environment (indoors, outdoors, food processing environment etc.) usually dictates the type of bait, and the active ingredient used. Rats are naturally shy of new objects and it might take a week before they take baits. Alternative rat control methods include break back trapping and glue boards, but these are generally not as effective, especially if the infestation is substantial. Finally, rat carcasses are frequently traced and removed to prevent secondary poisonings.