Thursday, August 28, 2008

Rats and Mice - General

This thread concerns the commensal rodents. The word commensal means "sharing ones table." This is the appropriate term as rats and mice have been "sharing" people's food and shelter for many years. And the word rodent means "to gnaw." Like all rodents, rats and mice possess a single pair of chisel-like incisor teeth that grow continuously throughout their lives. The incisors are kept filed and sharp primarily by the rodents grinding the incisors against on another, and secondarily by the rodents constant knowing on various objects.

The three species of commensal rodent pests are:

a. The House Mouse
b. The Norway Rat
C The Roof Rat

Occasionally, the deer mouse and less frequently, the white footed mouse, harvest mouse, and pocket mouse invade buildings located near fields or wooded areas, and may be confused with the house house. Field mice are easily separated from house mice by certain specific characteristics. These native rodents, including meadow mice (voles) and pack rats and other small mammals (shrews) that occasionally invade buildings.


Rodents have been responsible for, or implicated in, the spread of many diseases to people and domestic animals - especially in years past. Today, however, because of sanitation, effective drugs the disease threat from rodents is not as significant as it once was. In fact, the spread of disease by rodents is often not the primary reason for their control. But because of the habits of rodents (travelling and dwelling in sewers, garbage, etc.), there are still cases of human and animal diseases being transmitted by rodents, and there is also the potential of disease outbreaks that can be intensified and accelerated by rodents in cities where rats and mice live in close proximity to people. The following is a brief overview regarding the rodent transmitted diseases of most concern today!

Mouse Allergens: Research in 1999 of children in inner-city areas of eight major cities demonstrated that the house mouse carries a protein within its urine that can trigger severe cases of asthma and allergic rhinitis in susceptible people. Considering that mice typically urinate in micro droplets in many, many spots as the forage about inside a room, literally thousands of micro areas on surfaces can be covered with mouse urine inside homes or schools. As a result of this finding, the ordinary house mouse is considered much more of a health pest than in the past.

Hanta Virus: Because of the 1993-1995 outbreaks of Hanta viruses in the southwestern United States, there is heightened awareness this virus. The deer mouse has identified as the primary reservoir associated with this virus, although the cotton rat and the white-footed mouse have also been implicated with certain strains.

Plague: is the the "Black Death" that killed 25,000,000 people in Europe during the 14th century and millions of others bother earlier and later in history. Although plague does not now exist in commensal rodents in the US, it is still found in some native rodents such as ground squirrels in the western US, as well as in several other parts of the world.

Murine Typhus: Is a disease transmitted from infected rats and some other rodents to people also my the oriental rat flea and occasionally by the cat flea. The predominant reservoir for most areas where murine thyphus occurs are the Norway rat and the Roof rat. The organism enters the human blood stream via the bites of fleas or when infected feces are rubbed into the skin.

other diseases include rickettsial pox, salmonellosis, rat bite fever, weils diseases, rabies, lymphocytics, choriomeningitis, trichinosis, typhoid and dysentery.

Experts estimate that rats and mice destroy enough food each year to feed 200 million people. And some people want to let these guys go! Conservative annual estimates place the cost of rodent pest management programs to be well over $120 million dollars a year in the United States. Worldwide, the cost of rodent control is probably in the billions.

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