7/29/98

Rats: A Public Health Concern

Most people, if they think about them at all consider rats to be a symptom of urban blight. In reality, some estimates place the rat population at a level equal to the human population in many communities. It is not unusual for there to be large numbers of rats in rural and farm areas as well as cities.

From time to time, residents of Rocky Hill and Wethersfield are reminded that they too, share the environment with these rodents. While complaints of rat infestation are relatively rare in the health district, occasionally residents do see a rat or suspect some are living nearby. Because they present a public health concern, residents should know something about rats, their behavior, and the hazards they pose to human health.

In this country, there are two species of rats commonly found--the smaller, gray bellied rat (roof rat) and the larger Norway (ground) rat, which has coarse brownish-gray fur and a body length of 7 to 10 inches. (Add another 6-8 inches of tail.) The Norway rat is the more common species in much of the United States, including Connecticut. Having a life span of about 1 year, rats mature in 3 to 5 months, producing 4 to 7 litters throughout the year; each litter consists of 8 to 12 baby rats. They are omnivorous, eating meat and vegetation, with sharp teeth capable of gnawing through lead sheeting, adobe brick, cinder block, wood, cloth and aluminum sheeting. Rats are excellent swimmers, climbers (both vertically and horizontally),and jumpers. (They can jump as high as three feet off the ground and as much as 48 inches horizontally from a flat surface, and 8 feet horizontally from an elevation of 15 feet.) These versatile creatures can fall from a height of 50 feet without being injured, and can gain entrance through any

opening that is larger than a ½ inch square. They can also burrow vertically into the earth to a depth of 4 feet.

Besides the $5 billion of damage caused by rats each year from pawing and rat wastes, they can be responsible for a number of diseases in humans. These include rat bite fever, flea-borne plague, Rocky Mountain spotted fever, typhus, tapeworm, tularemia, trichinosis, salmonellosis, leptospirosis, and bacterial food poisoning.

The presence of rats is indicated by a number of signs--obviously seeing a live or dead rat is one clear indication. Burrows, typically near walls of buildings or other obstructions, are normally dug at an angle and are smaller than those dug by rabbits and muskrats. Rat tracks, about 3 inches wide, and rat runs (black markings of grease and hair) along packed down earth or floors inside and around buildings, are additional signs. Rat droppings (black, capsule shaped, about ½ to ¾ inch in size, may be found along runways, at feeding spots, and in harborage places. The discovery of gnawed materials and gnawed openings around doors, windows, or other obstacles in their path is further evidence of an infestation.

There are four basic steps to rodent control: Eliminating all shelters and harboring areas, removing all sources of food and water, rat-proofing infested buildings, and killing as many rats as possible. (Because anticoagulants have been used in rat poisons since the 1950's rats have developed a genetic immunity to the old poisons and new ones have been developed.)

To make sure rats do not become a problem, the following measures should be employed:

· Practice good sanitation. Keep areas clean, store food in covered metal containers, and use tightly covered garbage cans.

· Bird feeding should be limited to hanging feeders that are not overloaded to prevent bird seed from being available on the ground. Scattering bread and birdseed on the ground for birds or other wild life is not recommended. Pet food should be kept indoors.

· Cover or remove any standing water.

· Eliminate shelters and nesting places. Keep grass short, cut down weeds and vegetation that is close to buildings.

· Close in openings around cables, pipes, vents, cracks, doors and windows. Caulk, steel wool and metal barriers can all be helpful.

· Follow manufacturer's directions when using traps or rodenticide. If traps are insufficient, it is wise to consult an exterminator so that accidental poisoning of other animals, pets, and children is avoided.

· If a dead rat is found, it should not be handled with bare hands. The use of gloves and tongs or two long sticks to move the body and place it in two sealed plastic bags is recommended.

For further information about rats, call the Central Connecticut Health District at 721-2822.