Exotic Disease Summary
Bovine brucellosis
Causative agent
A bacterium, Brucella abortus.
Characteristics
a. Likely source(s) of this
disease (area it comes from)
Description
Has been found throughout the world, successfully
eradicated from a number of countries including New
Zealand and Australia (both reported their last case in
1989).
b. Likely cause(s) of this
disease (how it could get to
NZ)
Importation of infected cattle or semen.
c. Likely host animal(s)
Cattle are the main hosts, horses can also be affected.
d. How host(s) commonly
affected by this disease
Abortion and reduced fertility in cows and bulls.
Horses may have discharging swellings on the neck
and withers, leading to fistulous withers or poll evil.
Lameness can also occur.
e. How this disease is
commonly spread
An infected cow when it aborts or gives birth, will
shed huge numbers of the bacteria to be ingested
when other cattle come into contact with the placenta,
foetus, genitalia, or contaminated feed or water.
Bacteria are also shed between calvings in the milk,
urine and faeces.
Infected bulls can transmit the disease through their
semen and calves can be infected by their mothers
before they are born.
f. Animal behaviours that
could contribute to spread or
complicate control of the
disease
© Ministry of Agriculture and Forestry, 2006
Cows are naturally curious, investigating new calves
the newly calved cow.
Exotic Disease Summary: Bovine Brucellosis Version 1.0
Page 1
Characteristics
g. Farm or industry practice(s)
that could contribute to spread
or complicate control of the
disease
Description
Intensive grazing.
Holding aborting or aborted cows with other animals.
Movement of infected animals between herds.
Introduction of uninfected heifers to an infected herd
results in infection and abortion in the young cattle,
maintaining the infection in the herd.
h. Wildlife vectors that could
contribute to spread or
complicate control of the
disease
i. Useful treatments and/or
control measures for this
disease
Dogs, cats and hawks can move aborted foetuses and
placentas around the farm and to other local farms.
j. Times when these treatments
or controls may not be
appropriate - and why
k. Possible effects of this
disease on the NZ economy
Vaccination can cause disease in humans when
accidentally exposed (eg, Strain 19).
Vaccination.
Testing, identification and slaughter of infected
animals.
Costs of eradication.
Public health effects.
Potential trade impacts for live cattle, bovine semen
and embryos.
l. Severity of these effects
Low.
m. Possible effects of this
disease on the NZ natural
environment
Nil.
n. Severity of these effects
NA.
This disease is Zoonotic?
If YES
Characteristic
How it can be transferred to
humans
YES

NO

Description
Ingesting unpasteurised milk and dairy products.
Handling infected cows, tissues or discharges.
Aerosol transmission reported at slaughterhouses.
© Ministry of Agriculture and Forestry, 2006
Exotic Disease Summary: Bovine Brucellosis Version 1.0
Page 2
Characteristic
How easy it is to be transferred
Description
Can easily be caught by humans consuming
unpasteurised dairy products.
A risk for those working with cattle such as freezing
workers, farm workers, vets.
How severe the infection could
be for humans
© Ministry of Agriculture and Forestry, 2006
Called ‘undulent fever’ in humans it causes flu-like
symptoms. Brucellosis can be treated with antibiotics.
Can become chronic and recur for many years.
Exotic Disease Summary: Bovine Brucellosis Version 1.0
Page 3