Mycoplasmosis in Swine

MYCOPLASMOSIS IN SWINE
 
Classification
Division: Prokaryota
Class: Mollicutes
Order: Mycoplasmatales
Family: Mycoplasmataceae
Genus: 
Mycoplasma
Species 
(most common) 
: 
M. hyopneumoniae, M.
hyorhinis, M. hyosynoviae, M. suis
Other species: 
M. flocculare, M. sualvi, M. hyopharyngis, M.
arginii, M. bovigenitalium, M. buccale, M. gallinarum, M.
iners, M. mycoides, M. salivarium
Mollicutes
No cell wall
Plants, animals, humans
Low Gram +, small genomes, no biosynthetic
pathways -> amino acids, purines,
pyrimidines, and membrane components from
growth environment
Mycoplasma Hyopneumoniae
initiates a chronic insidious bronchopneumonia
known as 
enzootic pneumonia 
by suppression of
innate and acquired pulmonary immunity
allowing upper respiratory commensal bacteria
to proliferate in the lungs and contribute to
disease
Colony morphology
In culture, Mhyo grows slowly -> turbidity and an
acid color shift to the media 3-30 days after
inoculation of media
Inoculation of solid agar medium and incubation
in a 5-10% carbon dioxide atmosphere-> visible
colonies after 2-3 days of incubation
Strains are antigenically and genetically diverse
NO variable surface proteins -> varies it through
varies proteolytic events -> altered immunoblot
protein patterns
Pathogenesis
Colonization of airway epithelium
Stimulation of a prolonged inflammatory
reaction
Suppression and modulation of innate and
adaptive immune responses
Interaction with other infectious agents
Pathogenesis
1)
Colonization: binding to the cilia of epithelial
cells in the airways
Adhesion: P97
Colonization results in ciliostasis, clumping and
loss of cilia, and loss of bronchial epithelial and
goblet cells
 Reduction in the efficency of clearance of
debris and invading pathogens by the
mucociliary apparatus.
Pathogenesis
IMMUNOSUPPRESSIVE EFFECTS 
 upper
respiratory commensal bacteria are able to
establish and proliferate in the alveoli as
SECONDARY PATHOGENS!
ENZOOTIC PNEUMONIA
Virulence factor remain unknown
Pathogenesis
The innate and adaptive respiratory immune
response are also modulate 
 chronic
colonization of airways and prolonged
pulmonary inflammatory response.
Colonization of cilia
Infiltration of peribronchiolar and adjacent
perivascular connective tissue by
MACROPHAGES
 and both B and T
lymphocytes
Pathogenesis
Mhyo infection induces macrophages to
produce proinflammatory cytokines
IL-1, IL-6, IL-8 and tumor necrosis factor-
α
, IL-
10, IL-12, IL-18 (its secretion of interferon-
γ
 is
inhibited)
DOWNREGULATION OF CELLMEDIATE
IMMUNITY! Stimulation of the inflammation
which causes tissue injuries in the lungs
Transmission
Direct trasmission through nose to nose
contact
Airborne transmission
Vertical transmission (from sow to pig and
then between littermate or penmates)
Signs
All ages
Incubation period is unpredictable, it spreads
slowly, clinical disease begins at 2-6 months
Morbidity 100%
EPIDEMIC FORM
Spreads rapidly
Coughing, acute respiratory distress, pyrexia,
death
Signs
ENDEMIC FORM
Transition in 2-5 months
Dry, nonproductive cough (2-3 weeks or
persists)
Fever, decreased appetite, labored breathing
or prostration due to secondary pathogens
Pigs will appear fairly healty, but we will have
greater dispersion in size if we reduced feed
intake
Gross lesions
Acute epidemic respiratory mycoplasmosis:
Cranial ventral or diffuses increased firmness,
failure to collapse, marked edema of the
lungs.
Chronically affected enzootic pneumonia:
Purple to gray rubbery consolidation of the
cranial ventral portions of the lungs in a
lobular pattern
Gross lesions
Uncomplicated infection:
Lesion of smaller portion of the lungs and on cut
surface, parenchyma uniform in color, catarrhal
exudate from airways
Enzootic pneumonia+ secondary pathogens:
Lager portions of the lungs is are affected, more
firm and heavy, on cut surface are mottled by
aroborized clusters of gray to white exudate
distended alveoli, mucopurulent exudate from
airways
Gross lesions
Chronic recovered lesions:
Thickeness by firm white connective tissue of
interlobular connective tissue in the cranial
ventral lungs
Tracheobronchial lymph nodes are firm, moist
and enlarged
Microscopic lesions
Lymphocytes and fewer macrophages form
cuffs around the airways, and adjacent  blood
vessels and lymphocytes expand the
propriasubmucosa of the airways
Epithelium of the airways may be hyperplastic
Serous fluid and fluid distended macrophages,
fewer neutrophils, lymphocytes, plasma cells
in alveoli and airway lumens
Microscopic lesions
Chronic lesions:
Lymphocytic cuffs are more prominent and
contain lumphoid nodules
Increased numbers of globet cells and
hyperplasia of submucosal glands in bronchi
Enzootic pneumonia:
Exudate in alveoli and airway lumens is more
extensive and may contain dense aggregates of
secondary bacteria
Recovering lesions:
Collapsed and/or emphysematous alveoli
Diagnosis
Herd epidemiology
Culture on samples of lungs with
grosslyairway (4-8 weeks to grow)
Flourescent antibody (FA) or
immunohistochemistry (IHC) or in situ
hybridization (ISH) on tissue collected as soon
after death and fixed in 10% NBF (IHC and
ISH)or chilled and shipped on ice within 24 h
(FA)
Diagnosis
PCR on lung tissue, bronchial swabs, or
bronchial washings
Real-time PCR
Serology (positive or negative status)
Treatment
Antibiotics: 
quinolones
, tylosin, oxytetracycline,
tilmicosin, and tulathromycin
Other: tiamulin, danfloxacin, chlortetracycline,
lincomycin, tilmicosin
Little efficacy: polymyxin, erythromicin,
streptomycin, trimethoprim, sulfonamides
NO: penicillin, ampicillin, amoxicillin,
cephalosporin (they interfere with cell wall)
Resistance to: tetracyclines, macrolides,
lincosamides, flouruquinolones
OFTEN WE NEED TO USE MULTIPLE ANTIBIOTICS TO
CONTROL THE SECONDARY PATHOGENS TOO!
Prevention
Providing an optimal environment (air,
ventilation, temperature, number of animals,
space)
Strategy of control: all in- all out pig flow,
medicated and segregated early weaning
Eradication: treat the sows with antibiotics
and the pigs weaned at 6 days of age, and
segregated early weaning with the use of
multisite operation
Prevention
Using pigs cesarean-derived, colostrum-
deprived pigs to repopulate a herd
Vaccines: to control the clinical disease
associated with mycoplasma pneumonia. NOT
PREVENT Single or dual dose
+ antibiotics: to reduce clinical disease
Sow vaccination is controversial
Mycoplasma Hyorhinis
“ is the agent that causes polyserositis, arthritis,
and otitis. The organism is ubiquitous within the
swine population”
Pathogenesis
It adheres to ciliated epithelial cells within the
upper and lower respiratory tract of pigs
(=Mhyo)
Presence in the eustachian tube
Other pathogens and stress may facilitate the
spread
Once systemic 
 polyserositis and
polyarthritis in pigs less than 8 weeks
                             
 arthritis in pigs of 3-6 months
Signs
Polyserositis occurs in 3-10 weeks old pigs
Signs at 3-10 days PI: roughened hair coat, slight
fever, depression, reduced appetite, reluctance to
move, difficulty breathing, abdominal tenderness,
lameness and swollen joints
Acute signs: resolve after 10-14 days
Arthritis
lameness and swollen joints for 2-3 months, up to
6 months
Signs
Mhr pneumonia
Clinical signs are uncommon: dry nonproductive
cough indistinguishable from Mhyo
Otitis
Head tilt
Conjunctivitis
Reddening of the conjunctiva, crustin of the
margins of lids by exudate and tearing
Gross lesions
Septicemic Mhr
Fibrinopurulent pericarditis, pleuritis and
peritonitis. Affected serosal membranes are
thickened, cloudy and rough, with fibrous
adhesions
Joints are swollen with serosanguinous and
fibrinous synovial fluid. Synovial membranes
are swollen and hyperemic. Pannus, erosion of
articular cartilage and fibrous adhesions.
Gross lesions
Lesion in the lungs are the same of Mhyo but
milder
Otitis
Appearance of mycoplasmas among the cilia
in the auditory canal and middle ear, and
purulent exudate fill the middle ear
Diagnosis
Slinical signs and gross lesions
Culture or molecular methods on samples
from untreated animals with acute or
subacute clinical signs (swab of serosal surface
or joints with typical exudate or fibrin from
these locations)
PCR
Treatment and prevention
Tylosin or lincomycin
Preventin conditions that may predispose the
animal
NO VACCINE
Mycoplasma Hyosynoviae
“Cause of arthritis”
Mhs colonizes the respiratory tract of pigs and is
located in the upper portions. The organism can
persist in carrier swine indefinitely in the tonsils
In infected sow the organism IS NOT
TRANSMITTED TO PIGS UNTIL 4-8 weeks age
Pathogenesis
Acute phase
 lasts 1-2 weeks (the organism sprea to the joints
and tissues throughout the body) and occurs
after 1-2 weeks from the lameness and typically
2-3 weeks PI
Incubation period of arthritis: 4-9 day PI
Subacute and chronic phase
3-16 weeks after clinical arthritis
Tonsils and lympho nodes remain infected
Signs
Acutely lameness (3-5 month-old pigs)
Normal rectal temperature. Slight reduction in
appetite that laid to weight loss
Joints normal or swollen, soft and fluctuating
Acute sign lasts 3-10 days
Low mortality, 1-50% morbility
Gross lesions
Proliferation, swelling, edema, and hyperemia of
synovial membranes in infected joints
Small amount of fibrinous or fibrinopurulent
exudate may coat synovial membranes
Increased volume of synovial fluid (serofibrinous,
serosanguinous or cloudy and brownish)
Edema of periarticular tissues surrounding the
affected joints
In chronic phases: joints membranes may be
thickened by fibrosis
Microscopic lesions
Acute lesion in synovial membranes with
edema, hyperemia, hyperplasia of synovial
cells, and perivascular infiltration with
lymphocytes, plasma cells and macrophages
Diagnosis
Culture or PCR on joint fluid or synovial
membranes aseptically collected from
affected joints in acutely lame untreated
animals
Serology: complement fixation assay and
ELISA on serum samples collected during the
acute and subacute or chronic phase
Treatment
Enrofloxacin, 
lincomycin
, tetracycline and
tiamulin
Mhs is sensitive to tylosin, lincomycin and
valnemulin
NO VACCINE
Mycoplasma suis
“causes anemia in pigs”
Originally observed as a rickettsia-like or
anaplasmosis-like disease characterized by
icteroanemia, respiratory distress, weakness, and
fever occurring in 2-8 month-old pigs.
In 1950- 
E.suis
: described as two species (
E.suis an
d
Eperythrozoon parvum
), it was later determined
that they are the same organism at different stages
of maturity.
Etiology
Lack of intracellular parasitism, small size, lack
of cell wall, susceptibility to tetracyclines
Round to oval, 0.2-2
μ
m that adheres to the
surface of erythrocyte membranes and invade
it, residing in membran-bound vacuoles or
free in the cytoplasm
Epidemiology
Morbidity 10-60%, mortality ou to 90% in acute
disease
Transmission:
Direct expose by oral uptake of blood and blood
components
Living vectors (ectoparasites and insects)
Non living vectors (needles, surgical instrument
etc)
By semen, only if there is blood contamination
(rare)
Vertical transmission in utero
Pathogenesis
Experimentally incubation period: 3-10 days – natural incubation period is variable. Status
of carrier is also possible
Acute phase
Heavy bacteriemia 
 severe anemia
(decrease inpacked cell volume, totale red blood cells
count, and hemogliobin concentration is due to MASSIVE
PARASITISM OF RBCs)
RBCs with altered membranes are recognized ad
abnormal and removed from the circulation by the
spleen
Increased bleeding potential 
 consumptive
coagulopathy
Hypoglycemia and blood acidosis
GENERAL IMMUNOSUPPRESSION
Signs
Acute hemolytic disease and death in young
pigs, prepartum sows, and stressed weaned
and feeder pigs
In sows: fever, anorexia, lethargy, decreased
milk production, poor maternal behavior.
Clinical signs occur within 3-4 days of
introduction to the farrowing room or
immediatly after farrowing
Signs
Pallor, fever, icterus, cyanosis of the extremities
(ears)
Mild anemia and poor growth rates in weaned
and feeder pigs
Chronic infection
in animals with parasites: unthriftiness, pallor,
and skin hypersensitivity (urticaria)
Decreased reproductive efficiency evidenced by
sows with anestrus, delayed estrus, early
embryonic death and abortion
Diagnosis
Clinical signs and gematology results
Splenectomize a potentially infected pig or
inoculate a splenectomized pig with blood from
suspected pigs
PCR
Complement fixation
Indirect hemagglutination
ELISA
Real-time PCR
Treatment
Oxytetracycline, 20-30 mg/kg parenterally
Administration of oxytetracycline at time of
stress can prevent acute disease. Oral therapy
can reduce the incidence of anemia. NOT
PREVENT OUTBREAKS
Supportive therapy
Iron dextran injections (200 mg/pig) help
recovery and minimize mortality
Prevention
Supportive therapy
Preventin reinfection
Parasitic control and hygiene (changing
needles etc)
NO VACCINE
Control of animal movement 
(negative status ca be
assumed if serologica or PCR tests from serum of pigs in the
farrowing unit are negative or if transfusion fro at least 10 blood
samples into slenectomized pigs has no effect)
Bibliography
Jeffrey J zimmerman, Locke A Karriker, Alejandro
Ramirez, Kent J Schwartz, Gregory W Stevenson,
Disease of Swine, 10° edition 2012
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Mycoplasmosis in swine is caused by Mycoplasma species, with Mycoplasma hyopneumoniae as the most common. It leads to chronic bronchopneumonia and can suppress the immune system, allowing other bacteria to proliferate in the lungs. The disease is characterized by slow growth in culture, adhesion to airway epithelium, and immunosuppressive effects. Colonization, pathogenesis, and colony morphology play important roles in the progression of the disease.

  • Mycoplasmosis
  • Swine
  • Mycoplasma species
  • Pathogenesis
  • Disease

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  1. MYCOPLASMOSIS IN SWINE

  2. Classification Division: Prokaryota Class: Mollicutes Order: Mycoplasmatales Family: Mycoplasmataceae Genus: Mycoplasma Species (most common) : M. hyopneumoniae, M. hyorhinis, M. hyosynoviae, M. suis Other species: M. flocculare, M. sualvi, M. hyopharyngis, M. arginii, M. bovigenitalium, M. buccale, M. gallinarum, M. iners, M. mycoides, M. salivarium

  3. Mollicutes No cell wall Plants, animals, humans Low Gram +, small genomes, no biosynthetic pathways -> amino pyrimidines, and membrane components from growth environment acids, purines,

  4. Mycoplasma Hyopneumoniae initiates a chronic insidious bronchopneumonia known as enzootic pneumonia by suppression of innate and acquired allowing upper respiratory commensal bacteria to proliferate in the lungs and contribute to disease pulmonary immunity

  5. Colony morphology In culture, Mhyo grows slowly -> turbidity and an acid color shift to the media 3-30 days after inoculation of media Inoculation of solid agar medium and incubation in a 5-10% carbon dioxide atmosphere-> visible colonies after 2-3 days of incubation Strains are antigenically and genetically diverse NO variable surface proteins -> varies it through varies proteolytic events -> altered immunoblot protein patterns

  6. Pathogenesis Colonization of airway epithelium Stimulation of a prolonged inflammatory reaction Suppression and modulation of innate and adaptive immune responses Interaction with other infectious agents

  7. Pathogenesis 1) Colonization: binding to the cilia of epithelial cells in the airways Adhesion: P97 Colonization results in ciliostasis, clumping and loss of cilia, and loss of bronchial epithelial and goblet cells Reduction in the efficency of clearance of debris and invading mucociliary apparatus. pathogens by the

  8. Pathogenesis IMMUNOSUPPRESSIVE respiratory commensal bacteria are able to establish and proliferate in the alveoli as SECONDARY PATHOGENS! ENZOOTIC PNEUMONIA Virulence factor remain unknown EFFECTS upper

  9. Pathogenesis The innate and adaptive respiratory immune response are also modulate colonization of airways pulmonary inflammatory response. Colonization of cilia Infiltration of peribronchiolar and adjacent perivascular connective MACROPHAGES and lymphocytes chronic prolonged and tissue B by both and T

  10. Pathogenesis Mhyo produce proinflammatory cytokines IL-1, IL-6, IL-8 and tumor necrosis factor- , IL- 10, IL-12, IL-18 (its secretion of interferon- is inhibited) DOWNREGULATION IMMUNITY! Stimulation of the inflammation which causes tissue injuries in the lungs infection induces macrophages to OF CELLMEDIATE

  11. Transmission Direct trasmission through nose to nose contact Airborne transmission Vertical transmission (from sow to pig and then between littermate or penmates)

  12. Signs All ages Incubation period is unpredictable, it spreads slowly, clinical disease begins at 2-6 months Morbidity 100% EPIDEMIC FORM Spreads rapidly Coughing, acute respiratory distress, pyrexia, death

  13. Signs ENDEMIC FORM Transition in 2-5 months Dry, nonproductive cough (2-3 weeks or persists) Fever, decreased appetite, labored breathing or prostration due to secondary pathogens Pigs will appear fairly healty, but we will have greater dispersion in size if we reduced feed intake

  14. Gross lesions Acute epidemic respiratory mycoplasmosis: Cranial ventral or diffuses increased firmness, failure to collapse, marked edema of the lungs. Chronically affected enzootic pneumonia: Purple to gray rubbery consolidation of the cranial ventral portions of the lungs in a lobular pattern

  15. Gross lesions Uncomplicated infection: Lesion of smaller portion of the lungs and on cut surface, parenchyma uniform in color, catarrhal exudate from airways Enzootic pneumonia+ secondary pathogens: Lager portions of the lungs is are affected, more firm and heavy, on cut surface are mottled by aroborized clusters of gray to white exudate distended alveoli, mucopurulent exudate from airways

  16. Gross lesions Chronic recovered lesions: Thickeness by firm white connective tissue of interlobular connective tissue in the cranial ventral lungs Tracheobronchial lymph nodes are firm, moist and enlarged

  17. Microscopic lesions Lymphocytes and fewer macrophages form cuffs around the airways, and adjacent blood vessels and lymphocytes propriasubmucosa of the airways Epithelium of the airways may be hyperplastic Serous fluid and fluid distended macrophages, fewer neutrophils, lymphocytes, plasma cells in alveoli and airway lumens expand the

  18. Microscopic lesions Chronic lesions: Lymphocytic cuffs are more prominent and contain lumphoid nodules Increased numbers hyperplasia of submucosal glands in bronchi Enzootic pneumonia: Exudate in alveoli and airway lumens is more extensive and may contain dense aggregates of secondary bacteria Recovering lesions: Collapsed and/or emphysematous alveoli of globet cells and

  19. Diagnosis Herd epidemiology Culture grosslyairway (4-8 weeks to grow) Flourescent immunohistochemistry hybridization (ISH) on tissue collected as soon after death and fixed in 10% NBF (IHC and ISH)or chilled and shipped on ice within 24 h (FA) on samples of lungs with antibody (FA) or or (IHC) in situ

  20. Diagnosis PCR on lung tissue, bronchial swabs, or bronchial washings Real-time PCR Serology (positive or negative status)

  21. Treatment Antibiotics: quinolones, tylosin, oxytetracycline, tilmicosin, and tulathromycin Other: tiamulin, danfloxacin, chlortetracycline, lincomycin, tilmicosin Little efficacy: polymyxin, streptomycin, trimethoprim, sulfonamides NO: penicillin, ampicillin, cephalosporin (they interfere with cell wall) Resistance to: tetracyclines, lincosamides, flouruquinolones erythromicin, amoxicillin, macrolides, OFTEN WE NEED TO USE MULTIPLE ANTIBIOTICS TO CONTROL THE SECONDARY PATHOGENS TOO!

  22. Prevention Providing ventilation, temperature, number of animals, space) Strategy of control: all in- all out pig flow, medicated and segregated early weaning Eradication: treat the sows with antibiotics and the pigs weaned at 6 days of age, and segregated early weaning with the use of multisite operation an optimal environment (air,

  23. Prevention Using deprived pigs to repopulate a herd Vaccines: to control the clinical disease associated with mycoplasma pneumonia. NOT PREVENT Single or dual dose + antibiotics: to reduce clinical disease Sow vaccination is controversial pigs cesarean-derived, colostrum-

  24. Mycoplasma Hyorhinis is the agent that causes polyserositis, arthritis, and otitis. The organism is ubiquitous within the swine population

  25. Pathogenesis It adheres to ciliated epithelial cells within the upper and lower respiratory tract of pigs (=Mhyo) Presence in the eustachian tube Other pathogens and stress may facilitate the spread Once systemic polyarthritis in pigs less than 8 weeks arthritis in pigs of 3-6 months polyserositis and

  26. Signs Polyserositis occurs in 3-10 weeks old pigs Signs at 3-10 days PI: roughened hair coat, slight fever, depression, reduced appetite, reluctance to move, difficulty breathing, abdominal tenderness, lameness and swollen joints Acute signs: resolve after 10-14 days Arthritis lameness and swollen joints for 2-3 months, up to 6 months

  27. Signs Mhr pneumonia Clinical signs are uncommon: dry nonproductive cough indistinguishable from Mhyo Otitis Head tilt Conjunctivitis Reddening of the conjunctiva, crustin of the margins of lids by exudate and tearing

  28. Gross lesions Septicemic Mhr Fibrinopurulent peritonitis. Affected serosal membranes are thickened, cloudy and rough, with fibrous adhesions Joints are swollen with serosanguinous and fibrinous synovial fluid. Synovial membranes are swollen and hyperemic. Pannus, erosion of articular cartilage and fibrous adhesions. pericarditis, pleuritis and

  29. Gross lesions Lesion in the lungs are the same of Mhyo but milder Otitis Appearance of mycoplasmas among the cilia in the auditory canal and middle ear, and purulent exudate fill the middle ear

  30. Diagnosis Slinical signs and gross lesions Culture or molecular methods on samples from untreated animals subacute clinical signs (swab of serosal surface or joints with typical exudate or fibrin from these locations) PCR with acute or

  31. Treatment and prevention Tylosin or lincomycin Preventin conditions that may predispose the animal NO VACCINE

  32. Mycoplasma Hyosynoviae Cause of arthritis Mhs colonizes the respiratory tract of pigs and is located in the upper portions. The organism can persist in carrier swine indefinitely in the tonsils In infected sow the TRANSMITTED TO PIGS UNTIL 4-8 weeks age organism IS NOT

  33. Pathogenesis Acute phase lasts 1-2 weeks (the organism sprea to the joints and tissues throughout the body) and occurs after 1-2 weeks from the lameness and typically 2-3 weeks PI Incubation period of arthritis: 4-9 day PI Subacute and chronic phase 3-16 weeks after clinical arthritis Tonsils and lympho nodes remain infected

  34. Signs Acutely lameness (3-5 month-old pigs) Normal rectal temperature. Slight reduction in appetite that laid to weight loss Joints normal or swollen, soft and fluctuating Acute sign lasts 3-10 days Low mortality, 1-50% morbility

  35. Gross lesions Proliferation, swelling, edema, and hyperemia of synovial membranes in infected joints Small amount of fibrinous or fibrinopurulent exudate may coat synovial membranes Increased volume of synovial fluid (serofibrinous, serosanguinous or cloudy and brownish) Edema of periarticular tissues surrounding the affected joints In chronic phases: joints membranes may be thickened by fibrosis

  36. Microscopic lesions Acute lesion in synovial membranes with edema, hyperemia, hyperplasia of synovial cells, and perivascular lymphocytes, plasma cells and macrophages infiltration with

  37. Diagnosis Culture or PCR on joint fluid or synovial membranes aseptically affected joints in acutely lame untreated animals Serology: complement fixation assay and ELISA on serum samples collected during the acute and subacute or chronic phase collected from

  38. Treatment Enrofloxacin, tiamulin Mhs is sensitive to tylosin, lincomycin and valnemulin NO VACCINE lincomycin, tetracycline and

  39. Mycoplasma suis causes anemia in pigs Originally anaplasmosis-like icteroanemia, respiratory distress, weakness, and fever occurring in 2-8 month-old pigs. observed as a rickettsia-like characterized or by disease In 1950- E.suis: described as two species (E.suis and Eperythrozoon parvum), it was later determined that they are the same organism at different stages of maturity.

  40. Etiology Lack of intracellular parasitism, small size, lack of cell wall, susceptibility to tetracyclines Round to oval, 0.2-2 m that adheres to the surface of erythrocyte membranes and invade it, residing in membran-bound vacuoles or free in the cytoplasm

  41. Epidemiology Morbidity 10-60%, mortality ou to 90% in acute disease Transmission: Direct expose by oral uptake of blood and blood components Living vectors (ectoparasites and insects) Non living vectors (needles, surgical instrument etc) By semen, only if there is blood contamination (rare) Vertical transmission in utero

  42. Pathogenesis Experimentally incubation period: 3-10 days natural incubation period is variable. Status of carrier is also possible Acute phase Heavy bacteriemia severe anemia (decrease inpacked cell volume, totale red blood cells count, and hemogliobin concentration is due to MASSIVE PARASITISM OF RBCs) RBCs with altered membranes are recognized ad abnormal and removed from the circulation by the spleen Increased bleeding potential coagulopathy Hypoglycemia and blood acidosis GENERAL IMMUNOSUPPRESSION consumptive

  43. Signs Acute hemolytic disease and death in young pigs, prepartum sows, and stressed weaned and feeder pigs In sows: fever, anorexia, lethargy, decreased milk production, poor maternal behavior. Clinical signs occur within 3-4 days of introduction to the immediatly after farrowing farrowing room or

  44. Signs Pallor, fever, icterus, cyanosis of the extremities (ears) Mild anemia and poor growth rates in weaned and feeder pigs Chronic infection in animals with parasites: unthriftiness, pallor, and skin hypersensitivity (urticaria) Decreased reproductive efficiency evidenced by sows with anestrus, embryonic death and abortion delayed estrus, early

  45. Diagnosis Clinical signs and gematology results Splenectomize a potentially infected pig or inoculate a splenectomized pig with blood from suspected pigs PCR Complement fixation Indirect hemagglutination ELISA Real-time PCR

  46. Treatment Oxytetracycline, 20-30 mg/kg parenterally Administration of oxytetracycline at time of stress can prevent acute disease. Oral therapy can reduce the incidence of anemia. NOT PREVENT OUTBREAKS Supportive therapy Iron dextran injections (200 mg/pig) help recovery and minimize mortality

  47. Prevention Supportive therapy Preventin reinfection Parasitic needles etc) NO VACCINE Control of animal movement (negative status ca be assumed if serologica or PCR tests from serum of pigs in the farrowing unit are negative or if transfusion fro at least 10 blood samples into slenectomized pigs has no effect) control and hygiene (changing

  48. Bibliography Jeffrey J zimmerman, Locke A Karriker, Alejandro Ramirez, Kent J Schwartz, Gregory W Stevenson, Disease of Swine, 10 edition 2012

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