WORLD OF MICROBIOLOGY AND IMMUNOLOGY Veterinary microbiology575•
nique, Venter and his colleagues were able to sequence the
human genome, and the genomes of other organisms, includ-
ing the bacterium Haemophilus infuenzae,.
Venter was born in Salt Lake City, Utah. After high
school he seemed destined for a career as a surfer rather than
as a molecular biologist. But a tour of duty in Vietnam as a
hospital corpsman precipitated a change in the direction of his
life. He returned from Vietnam and entered university, earning
a doctorate in physiology and pharmacology from the
University of California at San Diego. After graduation he
took a research position at the National Institutes of Health.
While at NIH, Venter became frustrated at the then slow pace
of identifying and sequencing genes. He began to utilize a
technology that decodes only a portion of the DNAfrom nor-
mal copies of genes made by living cells. These partial tran-
scripts, called expressed sequence tags, could then be used to
identify the gene-coding regions on the DNA from which they
came. The result was to speed up the identification of genes.
Hundreds of genes could be discovered in only weeks using
the method.
Supported by venture capital, Venter started a nonprofit
company called The Institute for Genomic Research(TIGR) in
the mid-1990s. TIGR produced thousands of the expressed
sequence tag probes to the human genome.
Venter’s success and technical insight attracted the
interest of PE Biosystems, makers of automated DNA
sequencers. With financial and equipment backing from PE
Biosystems, Venter left TIGR and formed a private for-profit
company, Celera (meaning ‘swift’ in Latin). The aim was
to decode the human genome faster than the government
effort that was underway. Celera commenced operations in
May 1998.
Another of Venter’s accomplishments was to use a non-
traditional approach to quickly sequence DNA. At that time,
DNA was typically sequenced by dividing it into several large
pieces and then decoding each piece. Venter devised the so-
called shotgun method, in which a genome was blown apart
into many small bits and then to sequence them without regard
to their position. Following sequencing, supercomputer power
would reassemble the bits of sequence into the intact genome
sequence. The technique, which was extremely controversial,
was tried first on the genome of the fruit fly Drosophila.In
only a year the fruit fly genome sequence was obtained. The
sequencing of the genome of the bacterium H. influenzaefol-
lowed this.
Although the privatization of human genome sequence
data remains highly controversial, Venter’s accomplishments
are considerable, both technically and as a force within the sci-
entific community to spur genome sequencing.See alsoDNA (Deoxyribonucleic acid); DNA hybridization;
Economic uses and benefits of microorganisms; Genetic code;
Genetic identification of microorganisms; Genetic mapping;
Genetic regulation of eukaryotic cells; Genetic regulation of
prokaryotic cells; Genotype and phenotype; Immunogenetics;
Molecular biology and molecular geneticsVVeterinary microbiologyETERINARY MICROBIOLOGY
Veterinary microbiology is concerned with the microorgan-
isms, both beneficial and disease causing, to non-human ani-
mal life. For a small animal veterinarian, the typical animals
of concern are domesticated animals, such as dogs, cats,
birds, fish, and reptiles. Large animal veterinarians focus on
animals of economic importance, such as horses, cows,
sheep, and poultry.
The dogs and cats that are such a familiar part of the
household environment are subject to a variety of microbio-
logical origin ailments. As with humans, vaccinationof young
dogs and cats is a wise precaution to avoid microbiological
diseases later in life.
Cats can be infected by a number of virusesand bacte-
riathat cause respiratory tract infections. For example the bac-
terium Bordetella pertussis, the common cause of kennel
cough in dogs, also infects cats, causing the same persistent
cough. Another bacteria called Chlamydiacauses another res-
piratory disease, although most of the symptoms are apparent
in the eyes. Inflammationof the mucous covering of the eye-
lids (conjunctivitis) can be so severe that the eyes swell shut.
Cats are prone to viral infections. Coronavirus is com-
mon in environments such as animal shelters, where numbers
of cats live in close quarters. The virus causes an infection of
the intestinal tract. Feline panleukopenia is a very contagious
viral disease that causes a malaise and a decrease in the num-
ber of white blood cells. The immune disruption can leave the
cat vulnerable to other infections and can be lethal.
Fortunately, a protective vaccineexists. Like humans, cats are
also prone to herpesvirus infections. In cats the infection is in
the respiratory tract and eyes. Severe infections can produce
blindness. Another respiratory disease, reminiscent of a cold
in humans, is caused by a calicivirus. Pneumoniacan develop
and is frequently lethal. Finally the feline leukemia virus
causes cancer of the blood. The highly contagious nature of
this virus makes vaccination prudent for young kittens.
Dogs are likewise susceptible to bacterial and viral
infections. A virus known as parainfluenzae virus also causes
kennel cough. Dogs are also susceptible to coronavirus.
Members of the bacterial genus called Leptospiracan infect
the kidneys. This infection can be passed to humans and to
other animals. A very contagious viral infection, which typi-
cally accompanies bacterial infections, is called canine dis-
temper. Distemper attacks many organs in the body and can
leave the survivor permanently disabled. A vaccine against
distemper exists, but must be administered periodically
throughout the dog’s life to maintain the protection. Another
virus called parvovirus produces a highly contagious, often
fatal, infection. Once again, vaccination needs to be at regular
(usually yearly) intervals. Like humans, dogs are susceptible
to hepatitis, a destructive viral disease of the liver. In dogs that
have not been vaccinated, the liver infection can be debilitat-
ing. Finally, dogs are also susceptible to the viral agent of
rabies. The virus, often passed to the dog via the bite of
another rabid animal, can in turn be passed onto humans.
Fortunately again, vaccination can eliminated the risk of
acquiring rabies.womi_V 5/7/03 10:59 AM Page 575