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22 Cards in this Set
- Front
- Back
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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.
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What does moraxella bovis cause in cattle?
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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 |
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What are the clinical signs of infectious bovine keratoconjunctivitis?
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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_ |
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What is the epidemiology of moraxella?
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!!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. |
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How is Moraxella Bovis diagnosed? What are the predisposing factors?
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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 |
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Are vaccines available against Moraxella Bovis?
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Yes
Bacterin + Pilin based Other cell wall antigens may be protective too. |
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What does moraxella ovis cause? Can it cause dz in cows?
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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… |
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What are the four bugs in Pasteurellaceae? (PHAM)
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Pasteurella, Mannheimia, Haemophilus,
Actinobacillus |
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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_. |
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What tissue does Pasteurella feel most comfy residing on?
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Intimate relationship with _mucosal_ surfaces. A commensal in many species; some form of environmental/health change leads to disease.
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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 |
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What are the most common syndromes of pasteurella?
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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 |
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What toxin strain causes atrophic rhinitis of pigs?
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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 |
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What is PMT?
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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 |
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What adhesive factor do pathogenic Pasteurella strains produce?
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Pathogens produce _filamentous__ hemagglutinin (Pfh- also very big protein)
• Fimbriae, other adhesins may also be produced • These proteins may vary among strains |
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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 |
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What virulence factor causes disease in fowl cholera?
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The capsule instigates the host inflammatory and immune processes.
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What species does Hemorrhagic septicemia affect?
What bacteria is this a strain of? |
Pasteurella - Affects many species of mammal- primarily ungulates
Mannheimia - tropical climes |
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What is Pasteurella multicoda infection like in rabbits?
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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. |
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What is the primary path of transmission of rhinitis and Pasteurella to humans?
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Animal bites
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What organism is the primary cause of Shipping fever?
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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. |
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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. |
