Adult weights vary from region to region and may be
linked to the suitability of habitat, but usually range
MICE AS DISEASE CARRIERS
from l/2 to 1 ounce. Adult house mice vary in color
Excluding the spread of food poisoning, house
from light brown to dark gray but most often are a
mice are not as important as rats as carriers of disease
dusky gray or medium brown over most of their
and parasites. Yet their potential cannot be neglected.
bodies, except the belly, which may be a slightly
House mice and their parasites are implicated in the
lighter shade of their general color but never white.
transmission of a number of diseases.
The mouse has moderately large ears for its body
size. The tail is nearly hairless and about as long as
the body and head combined (2 l/2 to 4 inches). The
Bacterial food poisoning, salmonellosis, can be
feet are small in proportion to its body. The eyes are
spread when some foods are contaminated with
also relatively small.
infected rodent feces. Mice are probably more
Our native deer (white-footed) mice (Peromyscus
responsible than rats for the spread of this disease.
sp.), which often invade buildings adjacent to fields
and woodlands, are about the same size as or slightly
larger than house mice. Deer mice have a distinct,
Rickettsia akari is the causal agent of
bicolored tail; the upper portion is brown or gray and
rickettsialpox, a disease causing a rash of the
the underside is distinctly white, with well-defined line
chickenpox type. Rickettsialpox is transmitted from
where the two colors meet.
Meadow mice or voles (Microtus Sp.) sometimes
mouse to mouse, then to man by the bite of the
invade homes; they are less agile, have larger, chunky
bodies, and weigh at least twice as much as house
mice. They also have much shorter tails and small ears
Lymphocytic choriomeningitis is a virus infection
of house mice that may be transmitted to man (mainly
to children) through contaminated food or dust.
Leptospirosis (Weil's Disease)
The mouse can be a major carrier of leptospirosis
Weil's disease), although human cases are more
commonly caused by rats.
Rat-bite Fever, Ray Fungus & Ringworm
Rat-bite fever can be transmitted by house mice.
So can ray fungus, Actinomyces muris. Certain
tapeworms are spread in house-mouse droppings, and
ringworm, a skin fungus disease, can be carried to
man by mice or contracted indirectly from mice
through cats. Tularemia has also been linked to house
HABITS OF HOUSE MICE
Under optimum conditions, house mice breed year
round. Out-of-doors, house mice may tend toward
Dermatitis caused by the bites of mites has been
seasonal breeding, peaking in the spring and fall.
associated with house-mouse infestations. The
Environmental conditions, such as the availability and
uncomfortable skin irritation and itching can affect
quality of food, can influence frequency of
children and adults. Mites may spread through all
pregnancies, litter sizes, and survival. Under ideal
mouse-infested house or apartment during particular
conditions, females may produce as many as ten litters
times of the year, and the dermatitis is frequently
(about 50 young) in a year. At very high densities,
blamed on other causes (heat rash, allergies, fleas, and
however, reproduction may nearly cease despite the
presence of excess food and cover.
New-born mice are quite undeveloped, weighing
between 0.02 and 0.03 ounce and are nearly hairless.
Eyes and ears are closed, but by the end of two
The house mouse is a delicate, agile, little rodent.
weeks, the body is covered with hair and the eyes and
(See charts, chapter 1, pg 2 and chapter 2, pg 3.)
ears are open. At about three weeks, the young begin
Module Three Chapter 3, Pg 2