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22 Cards in this Set

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Is there Neisseria in animals?

What can it be confused with?
No - but there is Moraxella - look very similar, gram - coccobacilli, often in pairs.
What does moraxella bovis cause in cattle?
Infectious bovine keratoconjunctivitis.

!! Very common disease of cattle worldwide
–! Economic importance, decreases in milk production, growth, marketability.
Pink eye, New Forest disease
Highly contagious, transmitted 1° via flies
May have age related immunity
Virulence factors:
– Adhesive fimbriae-antigenically varies- key virulence determinant
– Hemolysin (like Apx, E. coli hemolysin)- also critical
– Proteases, etc. may be produced during infection
– Host response may participate in damage to the eye
What are the clinical signs of infectious bovine keratoconjunctivitis?
Caused by moraxella bovis.

Swelling of the conjunctiva, tearing, squinting
Decreased appetite- perhaps from pain in the eyes
Opacity of the cornea may progress from very minor to very severe
_Vascularization_ of the cornea in later infections
Uncommon: may progress to ulceration, leaking of eye contents,
blindness
Usually complete recovery in the absence of treatment- takes up to 3
wks. Early antibiotics can reduce _scarring_
What is the epidemiology of moraxella?
!!Disease most common in summer and fall; young cattle are more
susceptible
Infection can be very limited or up to 80% of animals in a herd.

Some bovine strains may be more sensitive

Can spread quickly.

Similar diseases via mycoplasma and chlamydia in sheep and goats.

Prevention rather than cure is best tool.
– Control flies, provide shade, vaccination available.
How is Moraxella Bovis diagnosed? What are the predisposing factors?
Diagnosis commonly based on signs, very fragile organism,must culture quickly.
– (also true with Neisseria).
Fluorescent antibody is available
Vitamin A deficiency? UV exposure? Nonpigmented eyelids? Perhaps feeding on grasses- scratching of eyes
Are vaccines available against Moraxella Bovis?
Yes

Bacterin + Pilin based
Other cell wall antigens may be protective too.
What does moraxella ovis cause? Can it cause dz in cows?
Common aerobic isolate in conjunctiva of small ruminants.
Causes infectious keratoconjunctivitis in sheep and goats.
Very similar biology as M. bovis- virulence, disease, etc.
Can cause disease in _M. bovis_-vaccinated cows…
What are the four bugs in Pasteurellaceae? (PHAM)
Pasteurella, Mannheimia, Haemophilus,
Actinobacillus
Is Pasteruella commensal?

How is it transmitted to other animals?
!! __commensal__ in many species, can survive a long time in
water, organic media.
!! Oropharyngeal flora of many animals- transmitted to other
animals (humans) via _bites_.
What tissue does Pasteurella feel most comfy residing on?
Intimate relationship with _mucosal_ surfaces. A commensal in many species; some form of environmental/health change leads to disease.
Do both Pasteurella and Mannheimia produce capsules?

What do different capsule types lead to?
Yes

Different capsule types lead to different dz.

!Antiphagocytic- antigenic mimicry
What are the most common syndromes of pasteurella?
Atrophic rhinitis- toxin-mediated disease of _pigs_
• Fowl cholera- many bird species
• Hemorrhagic septicemia
• Snuffles, etc.- rabbits
• Mannheimia haemolytica
• _Shipping_ fever in cattle, septicemia in sheep
What toxin strain causes atrophic rhinitis of pigs?
Pasteurella.

Strain specific disease- many nonpathogenic strains can be found in a herd- introduction of the AR+ strain can lead to initiation of disease.
• AR+ strains possess _toxin_ genes (PMT)
• Young pigs most susceptible- apparent age-dependent immunity
What is PMT?
The AR+ strains of Pasteurella that are toxins.

Injected into nasal tissue: __turbinate__ atrophy and snout deformation
• Mitogenic- rho activating toxin.
• causes cell division but no mineralization- leads to osteolysis
• Encoded by a bacteriophage
What adhesive factor do pathogenic Pasteurella strains produce?
Pathogens produce _filamentous__ hemagglutinin (Pfh- also very big protein)
• Fimbriae, other adhesins may also be produced
• These proteins may vary among strains
Not all strains of Pasteurella produce the toxin PMT. Which of the following do?

Atrophic rhinitis
Fowl cholera
hemorrhagic septicemia
Atrophic rhinitis - yes
Fowl cholera - no
hemorrhagic septicemia - no

Administration of capsule or LPS from FC and HS strains can mimic disease
What virulence factor causes disease in fowl cholera?
The capsule instigates the host inflammatory and immune processes.
What species does Hemorrhagic septicemia affect?

What bacteria is this a strain of?
Pasteurella - Affects many species of mammal- primarily ungulates
Mannheimia - tropical climes
What is Pasteurella multicoda infection like in rabbits?
Many tissues can be infected.
-__abscesses__ may form in many areas of the body
-tear ducts can block
-Purulent nasal or vaginal discharge
-Auditory tube- leading to loss of balance- “_wry__ neck” or torticollis (other pathogens can cause this as well)
-Bite/puncture wounds leading to abscesses
-Mastitis, metritis

20-70% of rabbits can carry P.m. Dominant R.T. infection in rabbits
Therapy _can't_ remove pathogen. Classic signs: Sneezing, “snoring, snuffling”. Rub nostrils with front legs. Thick yellowish discharge.
What is the primary path of transmission of rhinitis and Pasteurella to humans?
Animal bites
What organism is the primary cause of Shipping fever?
Not really fair to say because this is a polyvalent dz with many pathogens playing a role, BUT Mannheimia haemolytica - bovine pneumonic pasteurellosis is the big one.

Organism is a normal inhabitant of the bovine _upper respiratory tract_.

_multifactorial_ disease- environmental stress, 2° infectious
agents play a role in turning a commensal into a pathogen.
Spread via respiratory secretions/droplets
Generalized signs- Fever, loss of appetite, listlessness
Survivors commonly have lifelong damage to their respiratory
system.
Mannheimia also associated with bovine hemorrhagic
septicemias in tropical areas, may cause serious mastitis.
What Mannheimia toxin blocks phagocytosis at low concentrations and is cytotoxic at high concentrations?

Does Pasteurella have this toxin?
Leukotoxin (Lkt)

Pasteurella has similar toxins.

Toxicity is focused on bovine leukocytes. LPS/Lkt conjugates
may be important in disease.

In Mannheimia- toxin stimulates _calcium_ accumulation by
PMNs and other phagocytes. Messes with signaling, leads to
cell death, dysfunction. Can block mitogenesis in B cells,
maybe platelet fx.
At very high concentrations- cell lysis.