Mycoplasma

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Mycoplasma
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General Characteristics of Mycoplasma

• Relatively host specific
• Smallest free-living pathogens of animals
• Viruses may be smaller, but not free-living
• Normal flora of upper respiratory tract
• Bacteria with No cell wall
• Outer membrane
• No lipopolysaccharide layer (endotoxin)
• Weak gram negative stain

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Mycoplasma species

• Mycoplasma bovis
• Mycoplasma bovigenitalium
• Abortion, arthritis, vaginitis, seminal
  vesiculitis
  
• Mycoplasma dispar
• Pneumonia
• Mycoplasma bovoculi
• Conjunctivitis
• Mycoplasma californicum
• Mastitis

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Mycoplasma bovis

• Pneumonia
• Arthritis
• Abortion
• Abscesses

• Mastitis
• Middle ear infections
• Brain infections
• Keratoconjunctivitis

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Mycoplasma bovis

• Spread
• Aerosol
• Nasal secretions, coughing
• Oral ingestion
• Fences, bunks, troughs, nipples, buckets
• Direct contact with infected calves
• Milk young calves
• Milking machines, milkers hands dairy cows

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Mycoplasma bovis

• Pathogenesis
• Attaches to mucosal surfaces
• Invades tissues and liberates toxins that can
  cause severe tissue damage
  
• Enters bloodstream (septicemia)
• Spreads through blood to other tissues or body
  systems
  
• Joints, ears, eyes, udder

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Variable Surface Proteins (VSP)

• Over 20 VSP have been identified
• Found on outer surface of the plasma membrane
• Play a role as mediators for attachment to
  mucosa
  
• Help organism evade immune response
• Example
• If an immune response is mounted to VSP A, the
  organism can shut down expression of VSP A and
  begin to express another VSP.

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Mycoplasma bovis

• Suppresses the immune system
• Decreases T-lymphocyte activity
• May block response of T-lymphocytes to vaccines
• Kills lymphocytes
• Not the degree of lymphopenia seen with BVD

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Mycoplasma bovis

• Animals affected
• Young calves
• Stocker and feedlot calves
• Adult cows

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Stocker and Feedlot CalvesDairy Calves 2
Months of Age

• Mycoplasma bovis pneumonia
• Most common in 300-600 lb calves but does occur
  in 800 lb feedlot cattle
  
• Considered part of the BRD complex
• Is opportunistic
• Frequently associated with an underlying BVD
  infection

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Stocker and Feedlot CalvesDairy Calves 2
Months of Age

• Mycoplasma bovis pneumonia
• 3 to 4 weeks after arrival
• Stress from commingling, crowding, wet and cold
  weather or other similar events may increases
  incidence
  
• Can quickly become a pen problem
• Morbidity may reach 80 and mortality 25 (severe)

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Stocker and Feedlot CalvesDairy Calves 2
Months of Age

• Clinical signs of Mycoplasma bovis pneumonia
• Increased respiration
• Frequent, harsh, hacking cough
• Ocular and nasal discharge
• Fever
• Decreased appetite, weight loss

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Stocker and Feedlot CalvesDairy Calves 2
Months of Age
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Stocker and Feedlot CalvesDairy Calves 2
Months of Age

• Mycoplasma bovis arthritis
• First cases usually appear 1 week after
  pneumonia
  
• 25 of pneumonia cases will develop arthritis
• Strains of Mycoplasma bovis differ in their
  ability to cause arthritis
  
• Inflammation of synovial membrane and tendon
  sheaths
  
• Swelling extends above and below the joint
• Multiple joints
• May decrease appetite, may see muscle atrophy

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Stocker and Feedlot CalvesDairy Calves 2
Months of Age

• Middle ear infections
• Head tilt, drooped ears
• Off-feed
• Eye inflammation
• Reddened sclera and conjunctiva
  (keratoconjunctivitis)
  
• Occasional ulcerated cornea
• Usually mixed bacterial infections

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Stocker and Feedlot CalvesDairy Calves 2
Months of Age
Typical Observations

• 3 to 4 weeks after arrival
• calves pulled for pneumonia ? poor treatment
  response
  
• 1 to 2 weeks later
• arthritic calves are being pulled
• some calves have a head tilt, droopy ear, runny
  eyes
  
• affected calves become dehydrated, thin, and
  lethargic
  
• Most deaths occur 3 to 6 weeks after arrival

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Dairy Calves 2 to 8 Weeks of Age

• Source of Mycoplasma bovis
• Nasal discharge from infected cows or calves
• Contaminated waste milk
• Dirty, stressful calving conditions
• Nipples, pails, hutches
• Most often seen in winter
• Other viral and bacterial pathogens may
  predispose to Mycoplasma bovis infection

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Dairy Calves 2 to 8 Weeks of Age

• Clinical signs of Mycoplasma bovis infection
• Inflamed eyes conjunctivitis, excessive
  tearing
  
• Middle ear infection head tilt or drooped ear
• Arthritis swollen joints, difficulty standing
• Pneumonia
• Fever, lethargy, off-feed, swollen face (sinuses)

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Dairy Cows

• Mycoplasma bovis mastitis
• Contagious pathogen most commonly spread from cow
  to cow at milking
  
• Commonly persists from one lactation to the next
• All ages and any stage of lactation
• Common following purchase of cows or heifers

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Dairy Cows

• Clinical signs of Mycoplasma bovis mastitis
• Mild cases
• Normal milk, /- high SCC, decreased production
• Udder and teats may be swollen and firm
• Severe cases
• Brown to tan milk with water consistency and
  flakes
  
• High SCC, decreased production
• Swollen udder and teats
• Can be seen in conjunction with arthritis and/or
  pneumonia

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Diagnosing Mycoplasma bovis

• Tests
• Culture
• PCR polymerase chain reaction
• IHC immunohistochemistry
• Tissues
• Fresh (refrigerated) joint aspirate or lung
  tissue
  
• Do not send tissue in formalin, it degrades
  Mycoplasma bovis
  
• Nasal swabs and tracheal washes are not useful
  for a definitive diagnosis
  
• Fresh milk (refrigerated) for culture

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Treating Mycoplasma bovis

• Early treatment is essential treating chronics
  is usually futile
  
• Mycoplasma is not highly sensitive to many
  antibiotics
  
• Bio-Mycin 200 Oxytetracycline Injection
• Every 72 hours for 3 to 4 treatments (4.5 mL/100
  lb)
  
• Tylosin Injection may be beneficial
• Metaphylaxis
• Has been successful in stopping major pen
  problems
  
• Must be done early

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Preventing Mycoplasma bovis

• Prevention is key
• Stocker and feedlot calves
• Reduce stress, commingling, crowding
• Clean water tanks, bunks, and other equipment
• Protect against respiratory viruses, Mannheimia,
  Pasteurella, and Haemophilus
  
• Vaccinate against Mycoplasma bovis

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Preventing Mycoplasma bovis

• Young dairy calves
• Maintain clean calving conditions
• Feed high quality colostrum
• Feed pasteurized waste milk
• Housing
• Keep dry, well-ventilated practice all-in and
  all-out
  
• Separate from weaned calves, sick calves, and
  adult cows
  
• Protect against respiratory viruses, Mannheimia,
  Pasteurella, and Haemophilus
  
• Vaccinate against Mycoplasma bovis

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Preventing Mycoplasma bovis

• Dairy cows
• Culture all incoming cows and heifers for
  biosecurity
  
• Cull cows with Mycoplasma bovis mastitis
• Feed replacement heifers pasteurized waste milk
• Provide dry, well-ventilated housing
• Use proper milking techniques
• Protect against respiratory viruses, Mannheimia,
  Pasteurella, and Haemophilus
  
• Vaccinate against Mycoplasma bovis