—Lancaster Farming, Saturday, May 27,1978
22
Human brucellosis still a serious problem
WASHINGTON, D.C. -
With calving and farrowing
seasons now underway,
fanners and ranchers should
be aware that brucellosis
still poses some risk to
human health. Assisting
animal* at birth is one way
people may become exposed
to this disease.
Thanks to pasteurization
of milk and progress in
eradicating the disease in
livestock, human brucellosis
(sometimes called undulant
fever) is no longer a scourge
of rural areas.
“But it’s still considered
an occupational risk for
certain people,” said Dr.
Paul Becton, director of the
national brucellosis
eradication program for the
U.S. Department of
Agriculture (USDA) Animal
and Plant Health Inspection
Service.
According to Dr. Becton,
the disease now occurs most
frequently in packing plant
workers, livestock
producers, and
veterinarians - the people
most likely to handle in
fected animals or their
carcasses.
The early 1970’s saw a rise
in human cases, from 175 in
1973 to 354 in 1975 - a
doubling in just two years.
This increase was closely
linked with a resurgence of
the disease in cattle - a
trend which has since been
reversed.
“When plotted on a chart,”
said Dr. Becton, “the human
infection rate closely follows
the trend (generally
downward) in cattle in
fection. (See charts.)
“Through the cooperative
efforts of state-federal
animal health workers and
producers,” said Dr. Becton,
“the infection rate in cattle
is now down to one-half of
one per cent compared with
a five per cent rate 20 years
ago. Similarly, reported
human cases are now below
300 a year - a fraction of the
6,400 cases reported in 1947.”
The Department of Health,
Education and Welfare
(HEW), U.S. Public Health
Service, has an active in
terest in human brucellosis.
HEW’s Center for Disease
Control (CDC) in Atlanta'
carries brucellosis as a
reportable disease in its
weekly tabulations on
morbidity and mortality.
CDC also issues an annual
summary of brucellosis
surveillance.
Since 1960, CDC notes that
most human brucellosis in
this country has been of
swine origin. In two recent
years (1975 and 1976),
however, cattle-related
cases exceeded swine
related cases.
CDC figures show that
brucellosis predominately
affects men between the
ages of 2Qrand 60. This is the
age category of the working
force in this country, the
group most likely to acquire
brucellosis in the meat
packing and livestock in
dustries.
According to CDC, the
most probably source of
exposure to workers in the
meat processing industry is
swine. But, for workers in
the livestock industry -
producers, veterinarians,
market employees - the
most probably source is
cattle.
Dr. Becton noted there are
no cases on record of people
getting the disease by eating
meat. This is because the
bacteria that cause
brucellosis tend to localize in
the reproductive tract and
udder, parts that are
removed at slaughter. Also,
the bacteria are readily
killed by normal cooking
temperatures or
pasteurization.
Some natural food ad
vocates favor the use of raw
rather than pasteurized
milk. This preference for
unpasteurized milk may,
according to Dr. Becton,
present some risk to these
individuals.
In a recent 10-year period
(19654974), the eating or
drinking of unpasteurized
dairy products accounted for
some 190 human cases.
However, only one-third of
these was attributed to dairy
products produced in this
country, and none to com
mercially distributed
products.
“Though uncommon
today, human brucellosis is
a serious disease,” said Dr.
Becton, ‘'one that can cause
much misery.”
The disease is charac
terized by insidious onset of
fever, chills,, sweats,
weakness, pains, and aches.
Weakness bordering on
exhaustion is the most
outstanding complaint in
both acute mid chronic
cases.
Untreated, brucellosis in
man can result in a
debilitating, incapacitating
illness of long duration with
an occasional death.
Diagnosis presents one of
the difficult aspects of
human brucellosis. Since the
symptoms may only last
from a few days to a week
with each episode, they arc
commonly passed off as
some form of “the flu” or
other common infection.
Also, the time between
exposure and the ap
pearance of symptoms
varies from a few days to
several months; so the
source of infection also may
go unrecognized.
Chronic forms of
brucellosis, especially,
present diagnostic dif
ficulties because the
symptoms are charac
teristic of many disorders -
(Turn to Page 24)
BRUCELLOSIS: HUMAN CASES-BOVINE INCIDENCE
100,000 -
80,000 -
60.000 -
BOVINE INCIDENCE
(INFECTED HERDS)
»
'i
HUMAN CASES
I L_l I I I I I I 111 I I I I
40,000 -
20,000 -
.10,000 -
. 8,000 -
6,000 -
4,000 -
$ 2,000 -
g- 1,000
<0 800 -
« 600 -
<
400 -
200 -
100
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