HERD HEALTH                                       PIH-36


                           Swine Arthritis

Richard Ross, Iowa State University
Michael Hill, Purdue University
Richard L. Wood, Ames, Iowa

LeRoy Biehl, University of Illinois
Julie Ann Feeser, Taneytown, Maryland
Dave and Marty Huinker, Decorah, Iowa
Duane Miksch, University of Kentucky

     Arthritis is commonly recognized as a major factor in  swine
lameness. The disease is caused by infection of the joint and the
surrounding tissues by bacteria  or  mycoplasmas.  United  States
Department of Agriculture (USDA) meat inspection records indicate
that trimming the swine carcasses and discarding whole  carcasses
due  to  arthritis  are  leading  causes of loss at slaughter. Of
greater concern is the economic loss  that  occurs  on  the  farm
because  of  slower  and less efficient gains and reduced perfor-
mance by adult breeding stock  and  lactating  sows.  Death  loss
occurs in some instances but is not a major factor.

     Other factors in lameness in swine include those related  to
nutritional  imbalances  or  deficiencies,  foot  and leg lesions
resulting from trauma and improper conformation and  degenerative
bone and joint changes.

Streptococcal Arthritis

     Streptococci cause acute and chronic arthritis in  swine  of
all  ages. Most commonly this infection occurs in baby pigs where
the disease may be identified as part of the  ``joint-ill''  syn-
drome associated with navel infection.

     The streptococci are classified serologically  according  to
the  Lancefield  system. Representatives from virtually every one
of the Lancefield groups have been isolated from swine;  however,
most  isolates from naturally occurring arthritis belong to Group
C (Streptococcus equisimilis), Group L, or Group D (Streptococcus

     Besides  neonatal  diarrhea  and  pneumonia,   streptococcal
infection  is  probably one of the most common diseases affecting
young pigs.  Streptococcal infection occurs under many  types  of
management and environmental conditions. The organisms are common
in vaginal secretions, respiratory tract secretions and sow milk.
Streptococcus  suis  may  be carried in the tonsils of clinically
healthy animals. These organisms invade the pig's body by way  of
the  navel, foot or skin wounds or the tonsils. Rough flooring or
bedding material causes abrasions of the  legs  of  nursing  pigs
that undoubtedly facilitate invasion by these organisms.

     Streptococcal arthritis never affects a large percentage  of
pigs; the disease condition (morbidity rate) is usually less than
5%. Ten to 20% of affected pigs may die, either as  a  result  of
systemic  lesions produced during the septicemic (pathogenic bac-
teria in the blood) stage of the disease or by causes related  to
impaired mobility (starvation, overlaying, etc.).

     Clinical Signs. Acute streptococcal infection is  character-
ized by a fever, roughened hair coat, depression and lameness. As
the disease progresses, the affected pig may lose weight and have
marked  enlargement of the affected joints. One or several joints
may be involved; swelling is most often  observed  in  the  knee,
elbow and hock joints. The pain associated with the condition and
the resulting impairment of  movement  restrict  the  ability  of
affected pigs to nurse.

     Affected pigs are often stunted and have  chronic  arthritis
for  life.   Affected  joints contain increased amounts of cloudy
joint fluid with clots of fibrin. There is  swelling,  discolora-
tion  and redness of the membranes. The connective tissue capsule
around the joint is thickened and may contain small abscesses. As
the  disease becomes chronic there may be damage to the articular
cartilage. Lesions also are observed in the growth plates of  the
bones.  Other  signs indicative of systemic infection also may be
seen, particularly in S. suis infections.

     Diagnosis.  A sudden lameness with joint enlargement  and  a
fever  in pigs 1 to 3 weeks of age is highly suggestive of strep-
tococcal arthritis.  Joint and bone lesions also are very sugges-
tive. Systemic lesions, such as enlargement and congestion of the
lymph nodes, polyserositis (inflammation of the serous membrane),
pneumonia,  or meningitis are seen along with the arthritis in S.
suis infections. The organisms can be isolated from  the  acutely
arthritic joints by bacteriologic culture technics.

     Prevention and  Treatment.   The  recommended  treatment  in
cases of baby pig arthritis is generally penicillin. Treatment is
most effective if initiated before the disease  is  advanced.  If
inflammation  has  become chronic, the response to treatment will
be very poor. For S. suis infections, penicillin,  ampicillin  or
lincomycin have been recommended. Antibiotic susceptibility (sen-
sitivity) should be determined from bacterial cultures.

     Use of autogenous or commercially  available  vaccines  con-
taining  appropriate streptococcal antigens of Lancefield Group C
have been reported to control streptococcal arthritis. A  vaccine
containing  S.  suis  Types  I  and  II also has been reported to
prevent that disease. Streptococcal products have  been  used  to
vaccinate pregnant sows and thus confer immunity to the baby pigs
through the colostrum. Strong emphasis should be placed on selec-
tion  of  the  most  appropriate isolate for preparation of auto-
genous vaccines. The diversity of streptococci involved may  pre-
clude  development  of  appropriate products for all types of the

Erysipelas Arthritis

     Erysipelas can be an acute, subacute and  chronic  bacterial
disease  affecting  pigs  of  all  ages.  In  the acute form, the
disease is generalized, involving all body systems.  The  chronic
form  is  manifest  primarily  as arthritis, endocarditis, and/or
inflammation of  the  heart  valves.  Erysipelas  causes  serious
economic loss in most areas of the world where swine are raised.

     Erysipelothrix  rhusiopathiae,  the   causative   agent   of
erysipelas,  varies in virulence. It may be present in some herds
and not have an adverse effect. In other herds the signs  may  be
mild.  Yet in some herds it may cause severe, explosive outbreaks
with considerable death loss. Other factors  that  influence  the
severity  of  erysipelas  include  age  of  the pigs and level of
immunity.  Antibodies may originate  from  the  colostrum,  prior
exposure  to  low  virulent  strains,  or  vaccine.  There may be
differences in resistance related to genetic  influences,  nutri-
tional status or environmental temperature.

     E. rhusiopathiae is carried in the tonsils and intestines of
convalescent swine. Although it can be isolated from soil contam-
inated with swine feces, there is  no  evidence  to  support  the
belief  that it can survive for long periods or grow in soil. The
organism also causes arthritis in lambs, acute septicemic disease
in  turkeys and localized infection in humans who handle meat and

     Clinical Signs.  Acute swine erysipelas often appears  in  a
herd  with the sudden death of one or more pigs. Affected animals
may be depressed, have temperatures of 104o  to 108o  F., have poor
appetites  and be stiff, lame and reluctant to move. There may be
shifting of weight from one leg  to  another  in  an  attempt  to
relieve the pain. The feet may be placed well under the pig, giv-
ing the back an arched appearance. Such arthritic pigs  will  lie
down frequently and may be reluctant or unable to rise. Welt-like
lesions may develop in the skin during  the  acute  stage.  These
lesions  are  firm,  raised  and, in light skinned pigs, they may
appear light pink to dark purple.  They  are  usually  square  or
rhomboid  in shape and often are called ``diamond skin disease.''
Such lesions may heal or result in sloughing of necrotic  patches
of skin later on.

     Subacute erysipelas is similar to  acute  erysipelas  except
that it is milder. Temperatures are not so high, the appetite may
be normal, and there may be  only  minimal  skin  involvement  or

     Chronic swine erysipelas consists of chronic inflammation in
the heart valves and the joints. Chronic arthritis may affect one
or  several  joints  and  vary  considerably  in  the  amount  of
interference  with  locomotion.  Affected  joints may be markedly
enlarged, stiff and, in some  cases,  so  severely  damaged  that
joint function is no longer possible.

     Lesions in acute erysipelas are similar  to  those  seen  in
other  septicemic  diseases of swine, with hemorrhages in various
organs and serous  membranes  and  acute  inflammation  of  lymph
nodes. The spleen may be enlarged. Affected joints have increased
amounts of discolored joint fluid  and  swollen,  reddened  joint

     In chronic arthritis the joints have  thickened,  discolored
synovial  membranes  with  increased amounts of connective tissue
and infiltration of inflammatory white blood  cells.  The  change
may  also  extend  into the ligaments and tendon sheaths near the
joints. The joint fluid is red to brown and increased in  amount.
The  cartilage  covering  the  ends  of bones in the joint may be
severely eroded and necrotic. There may be growth of bone  around
the  margins  of  the  joint so that the joint cannot bend. Lymph
nodes draining arthritic joints  may  be  markedly  inflamed  and
enlarged several times the normal size.

     Diagnosis.  Erysipelas arthritis is best diagnosed by isola-
tion of the organism from affected joints; however, this is often
difficult to do because the organism  disappears  or  is  present
only  in very small numbers in the chronic stages of the disease.
Severe chronic inflammation of the joint membranes and  surround-
ing  tissues  and  damage to the bone and articular cartilage are
highly suggestive of  chronic  erysipelas  arthritis.  A  history
indicative  of  acute  erysipelas in the herd is suggestive of E.
rhusiopathiae in cases of chronic arthritis. Serologic tests have
been used for many years to aid in diagnosis, but because of dif-
ficulties in interpretation they generally are not  used  in  the

     Prevention and Treatment.  Vaccination is well-accepted as a
preventive for acute swine erysipelas.  Killed products, known as
bacterins, and certain live-attenuated  vaccines  are  available.
Selection  of  the  appropriate product depends on the individual
circumstances and experience on  a  given  farm  or  in  a  given
region. When bacterins are used, it is advisable to give 2 injec-
tions at 2 to 3 week intervals. Effective living  avirulent  vac-
cines  for  oral  administration  are also available. Vaccination
apparently does not protect against the chronic arthritis as well
as it protects against the acute disease.

     In general, it is advisable to  vaccinate  pigs  against  E.
rhusiopathiae  at  8 to 10 weeks of age. Vaccination of gilts and
sows 6 weeks prior to farrowing and again 2 weeks later has  been
thought  to  induce  antibodies  that are transferable to newborn
pigs via colostrum.

     Penicillin,  in  combination  with  antiserum   against   E.
rhusiopathiae,  is considered a good treatment for acute erysipe-
las. When this treatment is used properly in the acute stage,  it
is  likely that little chronic arthritis will develop. Animals in
which arthritis has already developed probably do not respond  as
well  and  those  with  chronic  arthritis do not respond to this
treatment. Corticosteroids may be used for temporary  alleviation
of the arthritic signs but probably do not influence the eventual
outcome of the process.

Mycoplasmal Arthritis

     Two  species  of  mycoplasmas  have  been  shown  to   cause
arthritis in pigs.  Mycoplasma hyosynoviae causes acute arthritis
in pigs 10 weeks and older and Mycoplasma hyorhinis causes  acute
and  chronic polyserositis and arthritis in pigs 3 to 10 weeks of
age and occasionally in young adult swine. Both  species  can  be
isolated from the nasal cavities, the throat and lungs of carrier
swine; however, they are  not  known  to  be  primary  causes  of
disease  in the respiratory tract. They can be distinguished from
Mycoplasma hyopneumoniae,  the  cause  of  chronic  pneumonia  in

Mycoplasma Hyosynoviae

     Arthritis caused by M. hyosynoviae occurs primarily in  pigs
12  to  24 weeks of age and occasionally in young adult swine. M.
hyosynoviae arthritis occurs in all breeds of swine, but it seems
to  be  more  frequent  and more severe in genetic lines that are
heavily muscled and that have poor leg conformation and poor  leg
action.  A degenerative joint disease (osteochondrosis) may be an
important predisposing factor in this disease. Stress  associated
with  movement  or  mixing,  transport  or changes in weather are
thought to predispose to the disease. It is quite common  to  see
M.  hyosynoviae  arthritis in young boars 7 to 10 days after they
have been introduced into a new herd.

     In most outbreaks of M. hyosynoviae arthritis, less than 10%
of the pigs are affected; however, in some severe cases more than
50% may be involved.  Very few affected pigs die.

     M. hyosynoviae becomes established in many pigs without pro-
ducing evidence of arthritis. A high percentage of adult swine in
infected herds carry the  organism  in  their  tonsils  for  long
periods.  Such carrier sows are undoubtedly the initial source of
the organism, resulting in infection of  some  young  pigs.   The
organism  appears to spread from pig to pig after weaning (5 to 7
weeks of age). Later at 2 to 3 months of age, most pigs have  the
organism in their throats.

     Clinical Signs.  Onset of M. hyosynoviae disease is  charac-
terized by sudden appearance of lameness in one or more legs. The
lameness varies in severity and duration, usually lasting 3 to 10
days. The pain may be so intense that the animal will not use the
affected leg. Arthritis in rear limbs is characterized  by  limp-
ing,  frequent  flexion  of the affected limb, shifting of weight
and altered stance.  The feet may be carried well under the  body
with  the back arched. Front limb involvement is characterized by
limping, stiffness or kneeling on the fetlock.  Affected  animals
usually  have  difficulty  in  rising  or  may be unable to rise.
Joint enlargement is usually not  observed  unless  the  hock  is
involved.  Acutely  arthritic  swine  may show slight to moderate
weight loss, slight to moderate loss of appetite and slight  rec-
tal temperature elevations.

     Joints with acute M.  hyosynoviae  arthritis  are  distended
with  turbid,  yellow  to  red-brown  fluid. Membranes lining the
joints are thickened and  yellow  to  red.  The  membranes  often
appear  granular  or  velvet-like.   Periarticular tissues may be
swollen and the tendon sheaths may be inflamed.  The  joint  car-
tilage generally appears normal.

     Diagnosis.  The age of the swine involved, the sudden  onset
of  lameness and the nature of the lesion are symptoms which make
tentative diagnosis possible. Joint fluid should be submitted for
microbiological  examination. M. hyosynoviae can be isolated from
about 50% of the acutely affected joints. Samples collected  from
chronically  affected  pigs or those treated with antibiotics are
usually negative for the organism.

     Prevention and Treatment.  Stressful conditions or practices
that  create  unnecessary  stress  should be minimized during the
susceptible age period in herds  troubled  with  M.   hyosynoviae
disease.  Breeding  stock  should  be selected for their good leg
conformation and leg action. Sows and boars should  not  be  pur-
chased  from seedstock herds having a history of severe arthritis

     Injectable tylosin (TylanO) has long been  available  as  an
effective  treatment for M. hyosynoviae disease. Lincomycin (Lin-
cocinO) is another drug shown to be effective  for  treatment  of
the  disease.  Treatment with either of these antibiotics is most
effective if given during the early stages of the disease.  Field
reports  as well as laboratory studies indicate the occurrence of
cases of the disease which do not respond  well  to  one  or  the
other of these antibiotics. Well-documented evidence of the value
of any medication given orally for prevention or treatment of  M.
hyosynoviae  disease  has not been presented. Corticosteroids are
sometimes used to alleviate pain associated with the arthritis.

     There  is  no  vaccine  for  prevention  of  M.  hyosynoviae
arthritis,  nor  is there evidence that M. hyopneumoniae vaccines
will induce protection against M.  hyosynoviae.

Mycoplasma Hyorhinis

     M. hyorhinis is a common inhabitant of the pigs' nasal  cav-
ity  and  a common secondary invader in swine pneumonia. It occa-
sionally produces inflammation of the  serous  membranes  of  the
pig's  body  and arthritis. The serous membranes cover the heart,
lungs, abdominal viscera and testes.

     M. hyorhinis disease occurs most  frequently  in  groups  of
pigs with other diseases such as pneumonia or enteritis and where
there is considerable stress caused by poor environmental  condi-
tions  or  poor  management. The disease may occur in young adult
breeding stock, especially  first  generation  surgically-derived
pigs  when they are stressed or mixed with conventional or second
generation SPF stock.

     In most outbreaks of M. hyorhinis disease, the incidence  of
clinical illness is low, but in occasional cases up to 25% of the
pigs may be affected.  Mortality is generally low.

     M. hyorhinis is carried in the upper respiratory tracts of a
small  percentage  of  adult  swine.  It  is  probably most often
transmitted from these carriers to a few young  pigs  which  then
serve to spread the organism among penmates. Most challenged pigs
never show any clinical signs of illness.  M. hyorhinis is  known
to  be a common secondary invader in pneumonia initiated by other
organisms and may, under some circumstances, cause  pneumonia  in
young pigs.

     Clinical Signs.  Pigs with  early  stages  of  M.  hyorhinis
disease  have roughened hair coats and are somewhat depressed. As
the disease progresses, clear evidence  of  abdominal  and  chest
pain  is  seen. The pigs show stretching movements with the front
and  hind  limbs  extended,  particularly  when  first   aroused.
Affected  pigs  may  be  tucked up and exhibit labored breathing.
Some animals lie on their chest rather than on their sides.  Poor
appetites  and slight temperature elevations may be seen. Some of
the affected pigs develop lameness and enlargement of the joints.
Swelling of the scrotum may be seen, especially in young boars.

     The inflammation in  the  body  cavities  may  continue  for
several  weeks  or  months  and result in stunting of growth. The
arthritis often continues for at least 6 months causing  lameness
and  reduced  mobility.  Clinical characteristics of the lameness
depend on the severity of the disease and  the  joints  involved.
The  lesions  produced  by  M. hyorhinis in joints are similar to
those produced by M. hyosynoviae  except  that  they  more  often
become  chronic.  There  is increased, discolored joint fluid and
the joint membranes are swollen and yellow to red. There  may  be
fibrin  clots in the joint fluid. Lesions in the chest, abdominal
and heart sac cavities consist of accumulation  of  cloudy  fluid
with  pieces  of  fibrin.  As  the  disease progresses, adhesions
develop. Such adhesions frequently are seen in pigs at slaughter.

     Diagnosis.  Appearance of arthritis accompanied by polysero-
sitis  (peritonitis, pleuritis and pericarditis) in 3 to 10 week-
old pigs is very suggestive of M. hyorhinis disease. The organism
can  be  isolated from the synovial fluid of arthritic joints and
from the exudate in the body cavities. This disease must be  dif-
ferentiated  from  a  very  similar  polyserositis  and arthritis
caused by Hemophilus spp.

     Prevention and Treatment.  Stress or other diseases that may
predispose  to M. hyorhinis disease such as pneumonia or diarrhea
should be controlled.

     There are no known effective treatments and no  vaccine  for
this  disease.  M. hyopneumoniae vaccines are not known to induce
cross-protection against M. hyorhinis.

Arthritis Associated with Other Septicemic Infections: Haemophilus parasuis and Actinobacillus suis

     Systemic  infections  with  bacteria  such  as   Haemophilus
parasuis  and Actinobacillus suis often include mainfestations of
arthritis. H. parasuis, known as Glassers disease, causes inflam-
mation  in  the pleural, pericardial and peritoneal cavities, the
joints and the meninges. Generalized signs of septicemia  may  be
seen  throughout the lymph nodes and abdominal organs.  Arthritis
is manifest as increased discolored fluid in the affected  joints
and  inflammation of the membranes lining the joint spaces. Simi-
lar disease may be seen  with  other  bacterial  agents  such  as
Actinobacillus suis.

     Diagnosis of bacterial septicemic disease with arthritis  is
usually  based on demonstration of post-mortem lesions and isola-
tion of the causative organism. For therapy, treatment  early  in
the  course  of  the  disease  is mandatory. Specific antibiotics
which may be useful include penicillin or sulfonamides. Commerci-
aly available vaccines have been released recently which have the
potential to induce a good level of immunity. Herds with  ongoing
problems with H. parasuis may wish to consider vaccination.

Arthritis Associated with Tail Biting

     Tail biting is a habit common in growing and finishing pigs.
However,  growth and feed conversion are impaired. Frequently the
price of the animal is then docked at the time  of  sale  to  the

     Bite wounds in the tail or other sites such as the ear  pro-
vide  access  for  organisms  to  the blood stream. Streptococcus
spp., Staphylococcus spp. and Corynebacterium pyogenes  are  most
often  involved in arthritis of this type.  Arthritis due to tail
biting usually is manifested by large swellings of the  shoulder,
elbow, hock or stifle joints. Involvement of the vertebral column
may result from direct extension from the tail injury.

     Many management factors are involved in control of tail bit-
ing.  It  has  become  common practice to remove the tail of very
young pigs at the first joint from the body. Good technique  must
be  used  since contamination of the open wound following removal
of the tail may result in development of the  very  disease  that
you are attempting to avoid.

     Treatment of arthritis resulting from tail  biting  is  very

Osteochondrosis and Osteoarthrosis

     Osteochondrosis (OC, abnormal development of  cartilage  and
bone)  and osteoarthrosis (OA, degenerative joint disease) affect
young pigs of both genders in all major hog producing  countries.
Clinical  signs  develop when pigs are between 4 and 6 months and
tend to be  most  frequent  and  severe  in  fast-growing,  well-
muscled,  lean pigs. Poor conformation may be an associated prob-
lem. Deformities caused by OC include bow-legs and cross-legs  of
forelimbs,  and  cow-hocks  or  sickle-hocks.  The  common  sites
affected by OA are elbows and stifles, but shoulders, hips, hocks
and vertebral (spinal) joints also may be affected. Typically the
conditions affect many sites at the same time.

     Clinical signs include an unwillingness to move, a shortened
stride,  and,  if  elbows  are  affected, a desire to walk on the
knees; affected pigs are usually very vocal if they are forced to
move.  Gilts  and  sows  may be unwilling to stand for a boar and
affected boars either cannot mount or fall  off  the  sow  before
completing  a  service.  Although OC and OA can cause ``leg weak-
ness,'' the degree of lameness may be governed by the pain thres-
hold  of the pig; those which do not feel pain or become lame may
have extensive lesions.

     Although losses caused by OC and OA are often ignored,  they
are  probably  a  major  cause  of culling of breeding stock. The
estimated cost to the U.S. pig industry is in excess of $24  mil-
lion annually.

     The causes of OC and OA are poorly understood, but appear to
be multiple.  Heredity is thought to be an important predisposing
factor as there are breed differences in  susceptibility  for  OC
and  OA;  within  breeds there is variability in the frequency of
lesions in different lines. Although there has been  no  associa-
tion  between  OC  or  OA and nutrition, if pigs are fed less and
grow slowly, lesions develop more slowly  and  are  less  severe.
However,  by the time slow-growing pigs reach 230 lb, lesions are
similar to those in pigs fed to appetite. Pigs that  have  severe
lesions  at  slaughter may have overall slower growth rates. Ini-
tially, these pigs may have  the  fastest  growth,  but  as  pain
becomes  more severe they become inactive and eat less, thus los-
ing body condition.

     Excessive compressive forces over growth cartilages can ini-
tiate  or  worsen  lesions.  It  is, therefore, possible that the
increased muscle weight  or  the  greater  forces  across  joints
caused by larger muscles in contemporary pigs make lesions worse.
Exercise may improve movement of a pig and reduce  the  frequency
of  deformed limbs, but may not impact the severity of lesions in
joints. The results of putting pigs on softer  dirt  lots  or  in
deep  bedding  have been variable both for the degree of lameness
and the severity of lesions.

     Because specific causes of OC and OA have not  been  identi-
fied,  treatment,  control and prevention are difficult. Leanness
and muscle mass are related  to  a  higher  frequency  of  severe
lesions.  Lesions  also  occur in faster growing pigs.  Soundness
does not insure the absence of lesions, and lesions cannot always
be  detected grossly or radiologically. Drugs that alleviate pain
may simply mask the problems as may increased exercise or  softer
flooring.  Antimicrobial  compounds  are  of no value, because no
infections have caused OC or OA. At present, the best  preventive
measures  that  can  be suggested include selection for soundness
and conformation, adequate exercise on non-slippery  floors,  and
the  supply of a suitable ration for normal development of joints
and bones.  Further investigations are needed  to  study  genetic
influences  as  well as microscopic and biochemical evaluation of
cartilage from normal and affected pigs. Only more complex selec-
tion  criteria  would  screen out a large percentage of arthritic

     Reference to products in this publication is not intended to
be  an  endorsement to the exclusion of others which may be simi-
lar. Persons using such products assume responsibility for  their
use  in  accordance with current label directions of the manufac-

REV 12/91 (7M)


Cooperative Extension Work in  Agriculture  and  Home  Economics,
State  of Indiana, Purdue University and U.S. Department of Agri-
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