Diseases of Pigs

Scott P. Terrell, DVM, Diplomate ACVP

Veterinary Pathologist, Disney’s Animal ProgramsInstructor in Wildlife Pathology, UF CVM

North American Veterinary Licensing Examination (NAVLE)

360 multiple choice questions 6 blocks of 60 questions

Approx. 60 images (xrays, diagrams, photos, microscope

images, etc) Total 7.5 hours 55-65% to pass (90% pass)

North American Veterinary Licensing Examination (NAVLE)

Blueprint by species Small animal

• Canine 26%• Feline 22%• Pet bird 3%• Other (fish, lab, exotics) 3%

Food animal• Bovine 15%• Pigs 7%• Sheep / goat 2%

Horses 16%

Public health, poultry 6%

Gram positive or gram negative?SS BECLR DAMN (a ship)

S - Staphylococcus sp. S - Streptoccoccus sp. B - Bacillus sp. E - Erysipelothrix rhusiopathiae C - Clostridium sp. L - Listeria monocytogenes R - Rhodococcus equi D - Dermatophilus congolensis A - Actinomyces (Arcanobacterium) pyogenes M - Mycobacterium sp. (acid fast) N - Nocardiasp.

On to the pigs....

Ages of pigs are important

Neonates 0-3 weeks <4 kg

Weanlings/nursery 3-10 weeks 4-25 kg

Growers/finisher 10-26 weeks 25-120 kg

Breeders/adults >6-8 months >120 kg

Pig management

Backyard herds All in / all out SPF Segregrated early weaning Depop / repop

Pig medicine

Blood collection Jugular vein / anterior vena cava

IV injection Auricular vein Rubberband

Orderly thinking...

Multisystemic Diseases Respiratory Diseases Gastrointestinal Diseases Neurologic Diseases Musculoskeletal Diseases Reproductive Diseases Dermatology Miscellaneous

Multisystemic diseases

Erysipelas (Erysipelothrix rhusiopathiae) Glasser’s disease (Haemophilus parasuis) Salmonella PRRS (arterivirus) PWMWS (circovirus) Pseudorabies virus (herpes virus) Vitamin E / selenium deficiency

Erysipelas

Erysipelothrix rhusiopathiae Gram positive rod

Environmental contaminant most herds have carriers

Septicemia diamond skin, arthritis, endocarditis,

necrosis

Diamond skin disease

Valvular endocarditis

Erysipelas cont...

Treatment Penicillin Tetracyclins

Prevention and control Sanitation Vaccinate at weaning and then q6 months

Glasser’s disease (polyserositis)

Haemophilus parasuis Gram negative coccobacillus

Endemic, initiated by stress Polyserositis, septicemia (fibrinous)

Pleuritis Pericarditis Peritonitis Meningitis!!!

Glasser’s disease

Glasser’s cont...

Diagnosis Culture is difficult (but try it) Go with suspicion from gross lesions

Treatment Penicillins Tetracyclins

Prevention and control Reduce stress Vaccine at weaning then again 3-4 weeks later

Salmonella sp.

Salmonella cholerasuis Salmonella typhimurium

Zoonotic

Low-level endemnicity, carriers Septicemia

pyrexia, anorexia purple discoloration of the ears (infarction) Small or large intestinal diarrhea (button ulcers) Pneumonia Rectal strictures

Salmonella

Salmonella cont...

Diagnosis Aerobic culture

Treatment Neomycin in the feed/water for whole group Naxcel (ceftiofur) for individual

Prevention and control Sanitation All in - all out operation Various vaccines (live avirulent)

PRRS

Porcine reproduction and respiratory syndrome

Arterivirus Clinical signs - neonates

anorexia, lethargy, fever cyanosis of the ears, respiratory distress secondary bacterial pneumonia delayed or abnormal estrus cycle with

increased numbers of stillborns/mummies

PRRS cont...

Diagnosis serology, virus isolation IFA, IHC most common test used in the USA

Treatment Supportive care, treat secondary bacteria

Control closed herds change feed if contaminated by mycotoxins (*) RespPRRS vaccine

Post weaning multisystemic wasting syndrome (PWMWS)

Porcine circovirus -2 Relatively new disease Responsible for many of the

clinical signs associated with “atypical PRRS virus”.

PWMWS

Clinical signs Wasting in weanling pigs Enlarged peripheral lymph nodes Evidence of pneumonia

Diagnosis Necropsy-

• Granulomatous lymphadenitis and pneumonia• Intracytoplasmic inclusions

Serology, IFA

PWMWS

Treatment None Supportive care Euthanasia of affected animals

Control Difficult at this time Carrier animals are important

Pseudorabies

Aujesky’s disease Herpes virus Dogs, cats, domestic ruminants Not humans!

Pseudorabies cont...

Baby piglets up to 100% mortality neurologic dz, vomiting, diarrhea Ulcers on oral cavity and esophagus

Weanling/growers up to 60% mortality in weanlings, 0-15% in

finishers pneumonia impt, neurologic dz, vomiting, extreme

pyrexia

Adults - often inapparent can cause stillbirth/abortion

Pseudorabies cont... Reportable disease! Diagnosis

Necropsy - • histologic lesions in brain, ulcers in gi tract

Serum neutralization is standard test ELISA can be used as a screening test

Treatment - none Prevention

closed herd! quarantine! restrict wildlife vaccination

Pseudorabies

Pseudorabies

Regulation use of vaccine regulated by states federal regulations for monitoring

all animals over 6mo old must be tested 25% of herd tested q3months or... 10% of herd tested q1month

White muscle disease / Mulberry heart disease

Nursery or grower pigs Vitamin E / Selenium deficiency

Propionic acid destroys Vit E / Sel Rancid fat can destroy Midwest U.S. is selenium deficient

Clinical signs acute death (mulberry heart disease) muscle weakness (white muscle disease)

Vit E / Selenium cont...

Diagnosis Necropsy - hydropericardium, fibrinous

epicarditis, myocardial hemorrhage Diffise hepatic necrosis - hepatosis dietetica Liver selenium < 0.5 ug/g

Mulberry heart disease

Cardiovascular disease

Encephalomyocarditis virus Hog cholera African swine fever Erysipelas Vitamin E / selenium deficiency

EMC virus

Cardiovirus Clinical signs

• neonates - sudden death• older pigs - subclinical chronic myocarditis

Pathology• Epicardial hemorrhage often only lesion• May see white streaks or spots in myocardium• Heart may be enlarged, soft and pale• Hydropericardium, hydrothorax, pulmonary edema,

etc.• Non-suppurative myocarditis, meningitis, encephalitis

PigEMC virus myocarditis

Other cardiovascular conditions

Hog cholera - FAD African swine fever - FAD Erysipelas - valvular endocarditis Vitamin E / selenium deficiency

Mulberry heart disease Necrosis / degeneration

of myocardium

Respiratory diseases

Atrophic rhinitis Swine influenza Mycoplasma pneumoniae Actinobacillus pleuropneumoniae Pasteurella Verminous pneumonia

Atrophic rhinitis

Bordatella bronchiseptica Pasteurella multocida High ammonia Clinical signs

sneezing, sniffling twisted snouts excessive lacrimation epistaxis

Atrophic rhinitis cont...

Diagnosis Necropsy - cut snout at 2nd premolar Nasal culture for either organism

Treatment tetracyclines in the feed LA200 to neonates

Control and prevention all in all out, reduce stress, clean air vaccinate sows

Atrophic rhinitis

Swine influenza

Influenza virus Zoonotic Outbreaks associated with

movement or extreme weather changes

up to 100% morbidity low mortality unless secondary bacterial

infection complicates things

Swine influenza cont...

Diagnosis Necropsy - cranioventral pneumonia Fluorescent antibody test

Treatment - supportive Prevention

closed herd control secondary infections keep away from humans (no shows!)

Mycoplasma hyopneumoniae

Enzootic pneumonia Most common cause of chronic

pneumonia Chronic, non-productive cough Low mortality Secondary bacterial complication

Mycoplasma cont...

Diagnosis Necropsy - “plum colored”or pale cranio-

ventral pneumonia Culture to rule out secondary bacteria Fluorescent

antibody test on lung

Mycoplasma cont...

Treatment - Lincomycin in feed

Prevention - improve management

Actinobacillus pleuropneumonia

Intensive swine operations Inapparent carriers Peracute, acute, and chronic forms Clinical signs

severe respiratory distress death

Actinobacillus cont...

Diagnosis necropsy - fibrinous pleuropneumonia often diaphragmatic lobes most severe culture is difficult complement fixation serology

Treatment ceftiofur (Naxcel) and procaine penicillin

Control vaccination of young pigs

Contagious pleuropneumonia

Pasteurella multocida

Most common bacterial isolate from pig lungs

opportunistic pathogen mycoplasma, influenza, actinobacillus, stress

clinical signs moist productive cough dyspnea some die

Pasteurella cont...

Diagnosis necropsy - suppurative cranio-ventral

bronchopneumonia may be pleuritis similar to actinobacillus culture

Treatment - penicillin, tetracyclines Control

look for underlying disease medicate feed and water (tetracyclines)

Pasteurella pneumonia

Verminous pneumonia

Ascaris suum - direct life cycle

Metastrongylus elongatus - earthworm intermediate

Problem with pasture pigs Clinical signs

poor doer respiratory distress

Secondary bacterial infection “Milk spots” liver, worms in the GI Levamisole, ivermectin

Gastrointestinal diseases

Stomach Ulcers

Small intestine E. coli (piglets) TGE (piglets) Clostridium (piglets) Coccidiosis (>7 days) Rota virus (post weaning) Salmonella (any)

Gastrointestinal disease cont...

Large intestine Swine dysentery (grower/finishers) Proliferative enteropathy (grower/finishers)

• Hemorrhagic bowel syndrome• Proliferative illeitis

Whipworms (growers) Salmonella (any)

Gastric ulcer disease

Almost always the pars esophagea Non-specific lesions Can lead to “bleed-out” Predisposing factors...

Finely ground feed Stress Vit E/Selenium def

Melena, ulceration of squamous portion of stomach, anorexia

“Bleed out”

Colibacillosis

E. coli Most impt cause of diarrhea in

piglets <5 days old!!! Clinical signs

clear watery to pasty brown feces dehydration and depression death losses higher in younger pigs

Colibacillosis cont...

Diagnosis ph of feces (>8) culture of organism (large number) necropsy - dilated gas filled small intestine

Treatment Ampicillin, tetracyclin, gentamicin, fluids

Control sanitation, vaccination of sow

Colibacillosis

TGE - transmissable gastroenteritis

Coronavirus (similar to FIP) Epidemic form (all ages) Endemic form (1-8 weeks old) WINTER disease Clinical signs

Neonates - diarrhea with undigested milk Growers, finishers - diarrhea recovers <7days

Morbidity and mortality high in pigs <2weeks old

TGE cont...

Diagnosis ELISA, immunoflourescence of gut contents Necropsy

• undigested milk in small intestine• thin walled, transparent small intestine

Treatment - supportive Control

isolate new additions for 2 weeks, keep dogs and bird away (carriers)

Immunization of sows or piglets Grind up piglet guts and feed to pregnant sows

TGE

Clostridial enteritis

Clostridium perfringens type C sudden death in 1-2 day old piglets Clinical signs

BLOODY DIARRHEA

Diagnosis Necropsy - blood in jejunum with flecks of

mucosa, necrosis of small intestine Clinical signs Histopathology - large gram positive rods

Clostridial enteritis

Clostridial enteritis cont....

Treatment usually die too quickly type C antitoxin

Control Sanitation Type C antitoxin within minutes of birth Vaccination of sow Prophylactic bacitracin or penicillin to

piglets

Coccidiosis

Isospora suis piglets 5 days old to weaning Clinical signs

diarrhea (7-10 days of age) no blood acidic feces (in contrast to E. coli) Dehydration

Coccidiosis cont...

Diagnosis Diarrheas in pigs <7days old are not Isospora! Necropsy - fibrinonecrotic enteritis Histopathology - oocysts, merozoites Fecal flotation can be falsely negative

Treatment Adding coccidiostats to feed is ILLEGAL amprolium to piglets

Control - disinfection of farrowing area

Coccidiosis

Rota virus

Reovirus Almost all pigs are infected Diarrhea in post-weaned pigs Diagnosis - difficult

Necropsy-thin walled small intestine Histopathology Flourescent antibody test Electron microscopy

Rota virus cont...

Treatment Glucose and fluids Antimicrobials for concurrent infections

• E. coli• Isospora

Control Wean pigs on good nutritional diet MLV vaccine at 7 and 21 days (in water)

Dont forget Salmonella Salmonella typhimurium Salmonella cholerasuis Fibrinonecrotic enteritis or colitis

at necropsy Rectal strictures Culture of organism

Swine dysentery

Serpulina hyodysenteriae Grower / finishers Mortality can be up to 30% Clinical signs

diarrhea sometimes with blood eventually watery, bloody, mucoid most recover in 2 weeks but 30% may die

Swine dysentery cont...

Diagnosis Necropsy - mucohemorrhagic colitis histopathology Spiral shaped organism on dark field microscopy Culture is definitive

Treatment Lincomycin in water

Control medicated water, depopulation, close herd vaccine only reduces clinical signs

Swine dysentery

Swine dysentery

Proliferative enteropathy

Lawsonia intracellulare proliferative illeitis, hemorrhagic bowel

syndrome

Large intestine Weanlings and older Clinical signs

intermittant diarrhea can be hemorrhagic diarrhea anemia (think gastric ulcer first)

Proliferative enteropathy cont...

Diagnosis Necropsy - “garden hose” ilium and colon

– can be hemorrhagic or fibrinonecrotic Histopathology - intracellular, silver positive DNA probes

Treatment and control No specific treatment Reduce stress Medicate feed - tetracyclines, carbadox

Proliferative illeitis

Whipworms

Trichuris suis 2-6 months of age Large intestine Clinical signs

diarrhea with mucus and blood anemia (2 DDX?)

Diagnosis - fecal float, fibrinnecrotic colitis Control - dichlorvos and fenbendazole

Whipworms

Don’t forget Salmonella!

Salmonella typhimurium Salmonella cholersuis

associated with rectal strictures?

Can be large intestine Fibrinonecrotic colitis Rectal strictures Culture

Parasites of pigs

Trichuris suis - colon Ascaris suum - small intestine, milk

spots Stephanurus edentatus - kidney Macrocanthorynchus hirudinaceous -

small intestine

Neurological diseases

Hypoglycemia Streptococcus suis Salt poisoning Edema disease

Hypoglycemia

Newborn piglets Blood glucose <50 may develop

signs Clinical signs

convulsions shivering hypothermia gait abnormalities

Hypoglycemia cont...

Diagnosis Blood glucose Empty stomach

Treatment 20ml/kg 5% glucosa, warm em up

Control make sure the milk is flowing

Streptococcus suis

Streptococcal meningitis 3-12 weeks of age Clinical signs

fever, anorexia, depression tremors, blindness, ataxia, convulsions

Diagnosis Necropsy - suppurative meningitis Culture of CSF or meningeal swab

Strep suis cont...

Treatment penicillin, tetracyclines must be quick!

Control minimize stress prophylactic antibiotics

Can be zoonotic - meningitis, headaches

Streptococcal meningitis

Salt poisoning

Usually due to water deprivation rather than too much Na

Causes hyperosmalarity of CNS resulting in swelling and edema

Clinical signs thirst, constipation depression, blindness, convulsions

Salt poisoning cont...

Diagnosis History Clinical pathology-eosinopenia, hypernatremia Histopathology - eosinophilic meningitis

Treatment None

Control provide free access to water reduce salt in diet

Edema disease

E. coli - toxin differs from GI form Shiga like toxin - vascular injury - edema

1-3 weeks post weaning Clinical signs

sudden death ataxia, convulsions, palpebral edema

Diagnosis palpebral edema, widespread edema in multiple sites Culture - pure culture from SI or colon Detection of toxin

Edema disease

Edema disease cont...

Treatment ineffectual if clinical signs have developed

Control Antibiotics in feed/water High fiber diets?

Musculoskeletal diseases

Arthritis S. suis, Erysipelothrix, A. pyogenes Mycoplasma hyosynoviae

Myodegenerative disease Malignant hyperthermia (PSE) White muscle disease

Rickets Fibrocartilagenous infarcts Osteochondrosis

Suppurative arthritis

Streptococcus suis Erysipelothrix rhusiopathiae Actinomyces pyogenes May see loss of cartilage Due to fighting, surgical contamination Distended joints, abscesses Penicillin - treatment often no good

Suppurative arthritis

Mycoplasmal arthritis

Mycoplasma hyosynoviae 4-12 weeks of age acute or chronic lameness non-suppurative arthritis/synovitis edema of synovial tissue Lincomysin to treat

Mycoplasmal arthritis

Malignant hyperthermia

Porcine stress syndrome, Pale soft edudative pork

Autosomal recessive gene Stress predisposes

Fighting, movement, handling Halothane anesthesia

Clinical signs muscle tremors, dyspnea, red areas of skin,

increased body temperature, muscle rigidity

Malignant hyperthermia

Treatment Remove stress Cool Dantrolene

Control genetic selection - DNA probe avoid stress

Malignant hyperthermia

White muscle disease / Mulberry heart disease

Nursery or grower pigs Vitamin E / Selenium deficiency

Propionic acid destroys Vit E / Sel Rancid fat can destroy Midwest U.S. is selenium deficient

Clinical signs acute death (mulberry heart disease) muscle weakness (white muscle disease)

Vit E / Selenium cont...

Diagnosis Necropsy - hydropericardium, fibrinous

epicarditis, myocardial hemorrhage hepatic necrosis - hepatosis dietetica Liver selenium < 0.5 ug/g

Treatment and control Vit E or selenium injection feed supplements

Mulberry heart disease

Rickets

Ca/P imbalance or Vit D deficiency Decreased mineralization of bone 3-5 months of age Pathologic fractures Distorted bones Adjust diet

Osteochondrosis

Grower pigs Rapid growth Usually involves humero-radial joint

Stifle less common

Fibrocartilagenous infarcts

Heavily muscled lean pigs Usually present down in hindlimbs Evidence of discospondylitis Rupture of nucleus pulposus Embolism of nucleus pulposus with

subsequent infarction of spinal cord

Reproductive disease

Parvovirus Leptospirosis PRRS Cystitis / pyelonephritis Brucellosis

Porcine parvovirus

100% prevalence Signs depend on time of infection

<30days - embryo resorbed 30-70days - mummy >70days - dead or weak, survive normally no other signs of illness

SMEDI - stillbirth, mummy, embryonic death, infertility

Diagnosis - detection of virus in mummy by immunofluorescence or by rising titer

Parvo - SMEDI

Porcine parvovirus cont...

Control Natural infection of gilts before breeding Commingle gilts with sows Grind up mummies and feed to gilts Vaccination!

• may still get some losses

Leptospirosis

Leptospira interrogans serovar pomona - most common serovar bratislava

Clinical signs Pyrexia, last trimester abortion, stillbirths

Diagnosis Culture difficult Dark field microscopy of fetal fluids, urine Serology (<1:800)

Leptospirosis cont...

Treatment Chlortetracycline in feed

Control Vaccination Gilts twice before first breeding Sows before every breeding

PRRS

Porcine reproductive/respiratory syndrome Premature farrowing Small weak piglets or stillborns increased numbers of mummies Delayed or abnormal estrus Serology to diagnose Vaccination for prevention

Cystitis / Pyelonephritis

Eubacterium suis Clinical signs

pyrexia, blood or pus in urine high urine pH

Diagnosis necropsy - hemorrhagic cystitis Culture difficult - anaerobic

Treatment - penicillin

Brucellosis

Brucella suis Clinical signs

abortion at any time in gestation infertility - many sows coming back into heat infected sows recover and deliver normally

Lesions mild endometritis arthritis orchitis

Brucellosis

Brucellosis cont...

Diagnosis Serology - card test Culture

Treatment and control Test and slaughter Zoonotic

Abortions/stillbirths

Parvo virus PRRS Pseudorabies Lepto

Dermatologic diseases

Mange Greasy pig disease Swine pox Erysipelas Pityriasis rosea (JPPD) PRRS associated

vasculitis/glomerulonephritis

Mange Sarcoptes scabei var suis Young nursery or grower pigs Clinical signs

intense pruritis, thickened skin poor production susceptible to other diseases

Diagnosis - clinical signs, skin scrape Treatment and control

acaricide (amitraz) topically, ivermectin injection

Mangy piglet

Mangy piglet

Sarcoptes scabei

Histopath

Greasy pig disease

Exudative dermatitis Staphylococcus hyicus Affects late preweaning pigs Clinical signs

exfoliation of skin, excess sebaceous secretion pruritis not a feature unless complicated my

mange

Diagnosis - clinical signs and culture

Greasy pigs

Greasy pig disease cont...

Treatment Injectible penicllin, oxytetracyline Tetracyclines in feed

Control Sanitation Control external parasites Good nutrition

Swine pox Swine pox virus Only pigs less than 4months old Clinical signs

papules 1-6 mm in diameter pustules, crusts clear spontaenously

Diagnosis - clinical signs, biopsy intracytoplasmic inclusion bodies

Treatment - not necessary

Swine pox

Erysipelas Erysipelothrix rhusiopathiae Diamond skin disease pigs 3months - 3years old Clinical signs

widespread ecchymotic hemorrhages due to microthrombi

arthritis, endocarditis

Diagnosis Diamond skin lesions pathognomonic Culture of blood, joints, lung, liver

Diamond skin disease

Erysipelas cont...

Treatment Penicillin is the drug of choice

Control General sanitation Bacterins or attenuated live vaccines

Pityriasis rosea

Juvenille pustular psoriaform dermatitis

Pseudo-ringworm Spontaneous regression

PRRS associated Vasculitis/glomerulonephritis

Newly described condition associated with PRRS virus infection

Type III hypersensitivity reaction Causing vasculitis Dermal and cutaneous infarction Large red sloughing skin lesions usually

over rear and legs Commonly associated renal disease

PRRS vasculitis/glomerulonephritis

Miscellaneous diseases

Swine lice Baby piglet anemia Eperythrozoonosis

Swine lice

Haematopinus suis Indicator of poor management Clinical signs

pruritis (mild), anemia, poor growing

Diagnosis visible to naked eye

Treatment - same as for mange

Baby pig anemia Iron deficiency Piglets iron demand is greater than the

sows milk Clinical signs

anemia within 2-3 days of birth dyspnea, edema, pale skin, lethargy

Diagnosis - clinical signs, CBC Treatment - 200mg iron dextran at 1-3

days of age

Eperythrozoonosis

Eperythrozoan suis Obligate intracellular parasite of RBC’s Clinical signs

pyrexia, icterus, anemia intravascular hemolysis necropsy - large spleen

Diagnosis - Giemsa stained blood smear Serology - 1:80 considered positive

Eperythrozoonosis cont...

Treatment Oxytetracycline injected or in feed

Control Control lice and fomite transmission Surgical instruments, needles, etc...

Pigweed

Amaranthus retroflexus Common in southeast Severe perirenal edema

Fumonensin

Fusarium moniliforme Hypertension Arteriolar medial proliferation Hemorrhagic pleural and pulmonary

edema*

Foreign diseases

Hog cholera pestivirus - splenic infarction is

pathognomonic

African swine fever iridovirus - hemorrhage in multiple areas

Vesicular diseases of swine Foot and mouth disease - apthavirus* Swine vesicular disease - enterovirus Vesicular exanthema - calicivirus Vesicular stomatitis - rhabdovirus

Case #1

Signalment: 10 weanling pigs History: dead and dying Necropsy findings:

yellow fibrin covering lungs yellow fibrin covering abdominal organs meninges are reddened

DDX?

Case #2

Signalment: several growers History: poor doers, chronic cough Clinical signs:

non-productive cough harsh lung sounds

Euthanize and necropsy: cranioventral pneumonia, plum-red color

DDX?

Case #3

Signalment: 2 grower pig females History: diarrhea, weak Clinical signs:

pale mucous membranes perineum stained with feces

One dies - necropsy findings: Large intestine markedly thickened and

contains small amount of blood

DDX

Case #4

Signalment: 1 piglet just weaned History: sudden death Clinical signs: dead! Necropsy findings:

subQ expanded by fluid, eyelids swollen mesentery and omentum expanded by fluid

Diagnosis? How do you confirm?

Case #5

Signalment: breeding sows History:

decreased fertility litters have contained dried up small fetuses

Clinical signs: none in the sows

DDX? How do you confirm your top differential?

Case #6

Signalment: many weanlings History: lameness Clinical signs

swollen painful hocks fever, one has pulmonary edema on xrays

Aspiration of joint reveals pus DDX?

Case #7

Signalment: young nursery pigs History: very itchy, bad skin Clinical signs:

dermatitis, pustules intense pruritis, self trauma

DDX? Diagnostic tests?

THE END!!!