Livestock Health, Management and Production › Animal Health Management › Review of issues that
influence animal health management
Animal Health Management
Review of issues that influence Animal Health Management
Author: Dr Mary-Louise Penrith.
Licensed under a Creative Commons Attribution license.
DISEASES OF IMPORTANCE TO LIVESTOCK PRODUCTION AND
TRADE
Infectious animal diseases can affect livestock trade in two important ways. Firstly, there are the so-called
transboundary animal diseases (TADs) (see also modules on high impact diseases and on marketing
and trade) that have the capacity for rapid spread over long distances and are feared by countries that
have never had them or have eradicated them. For this reason they are highly trade-sensitive and
countries that are free of them require assurances that they will not import them when they import
livestock or livestock commodities. The World Trade Organization has mandated the OIE to develop
standards for trade in live animals and livestock commodities that will prevent the spread of TADs. These
standards constitute the Terrestrial Animal Health Code which is updated annually and is available on the
OIE website (www.oie.int). Secondly, there are diseases, including TADs, which affect animal production
and consequently reduce the amount and quality of animals available for trade. At the subsistence level
of livestock production, where trade may not be an important issue, these diseases can jeopardise
household food security. In poor mixed farming systems livestock are needed for crop production and if
they are not there to provide manure and traction families may not have enough to eat.
The important characteristics of the selected diseases are summarised in Table 3. For more details about
the diseases please refer to the relevant chapters in Coetzer, J.A.W. & Tustin. R.C. 2004. Infectious
Diseases of Livestock (2nd edn), Oxford University Press, Cape Town. References for Newcastle disease
and avian influenza are provided at the end of the section and more information is available from the
module on poultry health and production.
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Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Table 3 Characteristics of diseases important for production and trade
Disease
FMD
Viral disease that
affects cloven-
Geographical
distribution
Transmission
and reservoirs
Worldwide (Not N
Highly contagious;
Sensitive to low pH;
High, mainly via live
America, Australia,
direct contact with
cannot survive in
New Zealand and
most of Europe)
infected animals
matured muscle but
animals and bone-in
meat
and material;
survives for long
airborne in special
conditions
periods in lymphoid
Trade: Trade bans
tissues, bone
during outbreaks and
marrow, and in
some dairy products
permanent market
hoofed animals and
camelids
African buffalo
(Syncerus caffer)
Survival outside
host
Potential for
transboundary
spread
Zoonotic
potential
None
Effects on production
and trade
Production: Most severe
in high-producing dairy
cattle and in pigs
exclusion for producers
in endemic areas
are the reservoir
host
PPR
Viral disease of
sheep and goats
North, West and
Direct contact with
Ability to survive
Spread is by live
Central Africa as far
infected animals
infected animals
south as Tanzania;
south-western Asia
and material;
outside the host is
poor
airborne over short
distances
None
Production: Can cause
high mortality and also
production losses
and the potential for
spread is high
Trade: Uninfected
countries might ban live
goats from infected
countries
RVF
Serious viral
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Africa (including
Transmission to
Sensitive to
Spread is probably
RVF virus causes
Major losses can occur
Madagascar) and
animals is by a
temperature and
mainly by live
mild to
due to abortions and
the Near East
number of species
pH; long-term
infected animals;
occasionally
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
disease of domestic
ruminants
Geographical
distribution
(Saudi Arabia and
Yemen)
Transmission
and reservoirs
of mosquitoes
(Aedes, Culex)
Survival outside
host
survival is probably
in mosquitoes
Potential for
transboundary
spread
Zoonotic
potential
Fatal viral
neurological
death of young animals
mosquitoes may
serious and even
move over
fatal disease in
distances in
vehicles
humans; infection
Trade in live animals
is usually due to
may be banned during
outbreaks
contact with blood
of infected animals
Rabies
Effects on production
and trade
Worldwide. Many
Usually by bites of
Survival outside an
Spread would be
Rabies is a fatal
disease in humans
Usually only individual
countries that are
infected animals;
animal is very brief
mainly by infected
free of rabies are
islands
other routes
described are rare
under natural
conditions
animals incubating
the disease
Most cases
Infection is by oral
Prions are highly
Owing to the
In the 1990s BSE
Herds with an infected
occurred in UK
ingestion of infected
tissues
stable in tissues
lengthy incubation
was linked to a
cow were culled; most
and very high
period (years)
variant of
were valuable dairy
cattle
animals are affected but
outbreaks in cattle and
wildlife have caused
serious losses
disease of all
mammals including
humans
BSE
BSE emerged in UK
followed by other
in the 1980s. It is a
European countries,
temperatures are
before clinical signs
Creutzfeld-Jakob
fatal neurological
Canada, Japan and
disease (vCJD)
USA ex Canada; no
required to destroy
them
appear and long
disease caused by
a prion
persistence in meat
that appeared in
After the link to human
cases have been
(certain types of
younger people
disease was discovered
reported in the
tissue) and bone
there were massive
southern
meal the potential
and is invariably
fatal
for transboundary
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effects on trade due
public fear and to
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
Geographical
distribution
Transmission
and reservoirs
Survival outside
host
hemisphere
Potential for
transboundary
spread
Zoonotic
potential
spread is high
Effects on production
and trade
surveillance
requirements that are
not easy to achieve
BT
Africa, Asia,
Transmission by
The virus is labile; it
Spread is by
Australia, USA,
None
High mortality can occur
in sheep
movement of
Europe (recent
blood-sucking
midges (Culicoides
is probably
A vector-borne viral
maintained during
infected animals
disease of domestic
and wild ruminants
introduction to N
spp.)
winter in midges;
and possibly by
Outbreaks, particularly
ruminants can only
wind-borne midges;
in new areas, can cause
be infected by
midges
establishment
restrictions on
requires suitable
movement of live
animals including game
Europe now
apparently extinct)
midges to host the
virus
AHS
A vector-borne viral
disease of equines
Endemic in sub-
Transmission is by
The virus is labile;
Spread is by
Saharan Africa;
equines can only be
infected by midges
movement of
epidemics occurred
blood-sucking
midges (Culicoides
after introduction
spp.)
into Spain, Portugal,
North Africa and the
Dogs can be
Near and Middle
East
infected by eating
infected meat
Zebras are
considered to be
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infected animals;
None
AHS can cause high
mortality and loss of
working time in horses
the outbreak in
Spain was traced to
Movement restrictions
zebras imported
from Namibia
can have negative
effects on the high value
racing industry
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
Geographical
distribution
Transmission
and reservoirs
Survival outside
host
Potential for
transboundary
spread
Zoonotic
potential
Effects on production
and trade
reservoirs of the
virus
ASF
Endemic in sub-
Highly contagious
Long survival is
Spread over long
None
High mortality can cause
Saharan Africa and
and transmission
possible in a
distances is mainly
serious losses to pig
ASF is a highly fatal
in Sardinia (Italy); it
among domestic
suitable protein
by infected pork
producers, exacerbated
viral disease of
domestic pigs
occurred in Western
pigs is by direct
environment like
products; cross-
Europe, Caribbean
contact with
chilled or frozen
border sales of pigs
at times by drastic
control measures
countries and Brazil
infected pigs and
in the incubatory
(1960 – 1994) and
contaminated
pork and uncooked
pork products
in the Caucasus
phase of the
Trade restrictions are
objects and eating
disease may occur
applied to pigs and pork
and non-Caucasian
infected meat; it can
between
Russia (2007 –
present)
also be via argasid
ticks (Ornithodoros
neighbouring
countries
originating from infected
areas
spp.)
Common warthogs
(Phacochoerus
africanus) maintain
the virus in a
sylvatic cycle with
Ornithodoros
CSF
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Worldwide with the
CSF is transmitted
Long survival is
Spread over long
exception of the
directly by contact
possible in a
distances is mainly
None
High mortality can cause
serious losses to pig
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
Geographical
distribution
Transmission
and reservoirs
Survival outside
host
Potential for
transboundary
spread
Zoonotic
potential
Highly fatal viral
African region,
with infected pigs
suitable protein
disease of domestic
pigs
where it is only
and contaminated
environment like
endemic in
objects; it can be
chilled or frozen
at times by drastic
control measures
Madagascar. South
transmitted in
Africa and Mauritius
semen, vertically to
pork and uncooked
pork products
Trade restrictions are
have experienced
foetuses, and under
applied to pigs and pork
epidemics.
particular conditions
can be airborne
originating from infected
areas
Eradicated in North
by infected pork
products
Effects on production
and trade
producers, exacerbated
America and in
CBPP
Western Europe
Eurasian wild boar
with the exception
of wild boars
populations can
Formerly worldwide,
Direct contact
The organism
Spread is by
become reservoirs
of the virus
it is now restricted
between infected
cannot survive for
infected animals
A respiratory
to some countries in
Africa and Near and
Middle East
and susceptible
cattle
long outside the
host
that may harbour
disease of cattle
caused by a
mycoplasm
Outbreaks in naïve
populations can cause
high mortality
the mycoplasms in
their nasal cavities
Restrictions may be
up to 40 days
placed on buying
before becoming
animals from countries
that are infected
serologically
positive
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None
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
Anthrax
Geographical
distribution
Anthrax occurs
worldwide
Transmission
and reservoirs
Survival outside
host
Potential for
transboundary
spread
Zoonotic
potential
Effects on production
and trade
Transmission is
Spores can survive
Spread is by
Severity of
If carcasses of animals
usually by ingestion
for very long
movement of
disease in humans
that die of anthrax are
A serious bacterial
or inhalation of
periods (centuries)
material
depends on the
not dealt with promptly
disease that causes
bacilli or spores;
in soil. Bacilli do not
contaminated by
route of infection.
large outbreaks with
disease in a wide
variety of mammals
mechanical
survive long in
spores, for example
Percutaneous
100% mortality can
transmission by
carcasses and must
the hides of
infection results in
biting flies has been
reported
be released into the
animals; outbreaks
the skin form
occur in ruminants,
including in wildlife
environment for
sporulation to occur
have been traced to
(sores), while
hide drums
ingestion of
Anthrax is considered
imported into
infected meat
one of the foremost
Europe and USA
from Africa
results in the
potential bioterrorism
agents
pharyngeal form
that is fatal if not
treated. Inhalation
of spores can
result in serious,
often fatal
systemic disease
ECF and CD
Theileriosis is
caused by a
protozoan blood
parasite Theileria
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Both diseases are
Transmission is via
endemic in some
the bites of the
countries in subSaharan Africa
No survival outside
the host or vector
Spread is by
None
Both diseases can
movement of
cause high mortality and
ixodid tick vector,
infected cattle
ECF can also reduce
mainly
Rhipicephalus
(ECF) and buffalo
performance in endemic
areas
(CD) or ticks; it may
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
Geographical
distribution
parva; cattle are
Transmission
and reservoirs
Survival outside
host
Potential for
transboundary
spread
Zoonotic
potential
appendiculatus
occur between
There are restrictions on
neighbouring
countries
trade in buffalo from CD-
African buffalo are
affected
infected areas; some
reservoir hosts of
CD
Trypanosomosis
Nagana in cattle is
(nagana)
widespread in
Tsetse flies
(Glossina spp.)
tropical Africa and
transmit the
distribution is
trypanosomes that
cause nagana
determined by the
local trade restrictions
may result from ECF
The parasite cannot
Spread is by
Human sleeping
Mortality is usually low
survive outside the
host and vector
movement of
except in newly
infected cattle but
sickness is caused
by Trypanosoma
the disease can
brucei gambiense
affected cattle are less
only be established
and T. b.
rhodesiense
productive and often in
very poor condition
None
European cattle breeds
None
presence of the
vector
Bovine babesiosis
Heartwater
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Effects on production
and trade
where there are
tsetse flies
introduced cattle, but
The parasites
tropical, subtropical
The ticks
Rhipicephalus
and warm
(Boophilus)
temperate regions
decoloratus and
outside the host and
vectors
wherever the
vectors are present
R.(B.) microplus
Infected cattle or
ticks can introduce
babesiosis to new
areas as occurred
in Australia with the
introduction of B.
microplus
Throughout sub-
Ehrlichia
The parasite cannot
Infected cattle can
Saharan Africa,
ruminantium is
spread the agent
due to high mortality in
mainly in tropical
transmitted by ticks
survive outside the
host and vector
and the vector,
ruminants including
and subtropical
of the genus
which can become
some wild species when
Widespread in
cannot survive
transmit babesias
are most severely
affected
Major stock losses occur
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
Geographical
distribution
Transmission
and reservoirs
Survival outside
host
Potential for
transboundary
spread
areas; was
Amblyomma; A.
established if
established on two
Caribbean islands
variegatum is the
conditions are
suitable
most important
Zoonotic
potential
Effects on production
and trade
introduced into endemic
areas
vector in southern
Africa
Bovine
anaplasmosis
None
Worldwide; endemic
Ticks transmit the
The parasite cannot
Spread is by
The effects range from a
in most of southern
anaplasmas; the
movement of
drop in milk production,
Africa (cattle
farming areas)
main vector is
Rhipicephalus
survive outside the
host and vector
infected cattle and
weight loss and poor
this can result in
conditions with slow
(Boophilus)
outbreaks in non-
recovery to high
decoloratus, but
endemic areas but
mortality (up to 50%);
three other species
of Rhipicephalus
establishment is
temporary infertility may
only possible where
occur as well as
and Hyalomma
suitable tick vectors
occur
abortions and neonatal
deaths
marginatum rufipes
can transmit the
agent
Newcastle disease
Worldwide
Direct contact with
The virus is easily
Spread is mainly by
Mild conjunctivitis
ND can cause severe
movement of live
poultry
in humans has
been described
losses due to mortality
infected birds or
inactivated by
ND is a viral
contaminated
changes in pH and
disease of birds
material resulting in
disinfectants but
(probably all
ingestion or
faeces are a potent
species) that occurs
inhalation of
source of infection
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as well as drop in egg
production and growth
Trade restrictions may
Livestock Health, Management and Production › Animal Health Management › Review of issues that influence animal health management
Disease
Geographical
distribution
Transmission
and reservoirs
infected material
in mild to virulent
forms
Survival outside
host
Potential for
transboundary
spread
Zoonotic
potential
for other birds
Effects on production
and trade
occur during outbreaks
Ducks are relatively
resistant to ND
Avian influenza
Worldwide
Direct contact with
The virus is easily
Live infected poultry
H5N1 HPAI has
High mortality occurs
infected birds or
inactivated but can
and infected
caused more than
and because of the
Viral disease of
contaminated
persist in faeces at
migratory birds
300 human deaths
zoonotic potential even
birds that varies
matter, including
water, and aerosols
low temperatures
have proven highly
since 2002
birds infected with LPAI
for up to 44 days as
well as in water
efficient in moving
although humans
the virus over long
distances
are relatively
are killed so losses can
be very heavy
resistant to
infection
Trade restrictions are
from mild (low
pathogenic AI) to
highly fatal (highly
Some water birds
pathogenic AI,
HPAI)
appear to be
relatively resistant
severe if there is an
outbreak and trade is
also damaged by fear of
human disease
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