LESSON 2
ANIMAL-BORNE DISEASES
2-1.
GENERAL
Zoonotic diseases are diseases that are common to animals, but can be
transmitted to man. For this reason, these diseases have been a menace to man
throughout history. The pet you love so much could be a host for diseases which are
very dangerous to mankind. In this lesson, you will learn to identify some of the
zoonotic diseases with which you may come into contact. With an awareness of these
diseases, their general characteristics, modes of transmission, and clinical findings, you
will be alert for either treatment or prevention. The more important zoonotic diseases
include rabies, leptospirosis, brucellosis, anthrax, Q-fever, and tularemia.
2-2.
RABIES (HYDROPHOBIA)
Rabies is an acute infectious disease of the central nervous system to which all
warm-blooded animals, including man, are susceptible. It is a viral encephalitis which is
transmitted when infected saliva gains entry into the body by a bite through an open
wound. The host range for this disease is both the carnivorous and chiropterna (bat)
species to include skunks found in the Midwest and California, foxes found in the east
and southeast, raccoons from Florida and Georgia, bats found in the entire US, and
occasionally, there are cases in which coyotes, bobcats, wolves, and squirrels are rabid.
Domestic animals that are hosts for rabies are dogs, cats, cows, pigs, horses, and
mules. The virus travels in the nerves to the brain, multiplies, and then migrates along
the efferent nerves to the salivary glands. The incubation period is variable. It is
usually between two and eight weeks, but can vary from 10 days to eight months.
a. Signs and Symptoms. The prodromal phase lasts from two to four days,
and the patient suffers headache, a slight temperature elevation from 1-3F, malaise,
nervousness, and abnormal sensation around the site of the bite. During the excitation
phase (predominant phase up to the time of death), the victim has dilated pupils,
lacrimation, excessive perspiration, loss of swallowing reflex, excess salivation (frothy),
a fear of water (hydrophobia), increased apprehension, anxiety, insomnia, and maniacal
seizures.
b. First Aid Treatment. When the victim is bitten, wash the wound immediately
with copious amounts of saline and cleanse the area with large amounts of soap and
water. After this, thoroughly rinse with large amounts of saline and drown the wound
with 1-2 percent benzalkonium chloride. If necessary, debride the wound and
administer tetanus toxoid. It is generally not advised to perform immediate suturing.
MD0589
2-2
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