27 – Moraxella and Chlamydia Flashcards
Microbial characteristics: Moraxella
- Biocontainment level 2
- Gram negative
- STRICT anaerobes
Microbial characteristics: Chlamydia
- Biocontainment level 2 or 3
- Obligate intracellular parasites
o Genome reduction: rely on host metabolic machinery rather than having their own - Biphasic development
Chlamydia ‘lifecycle’
- Elementary bodies bind to cell surface
- Endocytosis occurs, formation of inclusion bodies
- Organisms becomes metabolically active
- Reticulocyte bodies divide
- Reticulocyte bodies then differentiated back into elementary bodies
- Elementary bodies escape by lysis or extrusion and infect other cells
What is the natural host or habitat of Moraxella?
- Found on mucous membranes of mammals
- Don’t survive well outside of host
- May be transmitted by insects
What is the natural host or habitat of Chlamydia?
- Elementary bodies somewhat resistant to environmental conditions
- Can survive for several days outside host
- Avian GIT=natural site for C. psittaci
- Asymptomatic infections are common (BIG PROBLEM!)
Virulence factors of Moraxella
- Type IV pilli
- Cytotoxin
- Transferrin and lactoferrin binding proteins
Virulence factors of Chlamydia
- *Virulence genes comprise 10% of their gene
- Various secretion systems
- Cytotoxin
What does Moraxella bovis cause in cattle?
- Infectious bovine keratoconjunctivitis (pink eye)
- Incubation period of 2 days to 3 weeks
What are the clinical signs of Moraxella bovis in cattle?
- Copious watery lacrimation
- Blepharospasm, photophobia
- Opacity may develop in center of cornea which may ulcerate
- Most cases recover
- In severe cases: eyes rupture=blindness
How is Moraxella bovis in cattle transmitted?
- Mechanical vectors: INSECTS
- *cattle are the reservoir
How do you treat Moraxella bovis in cattle?
- Early infections: respond to topical antimicrobials
o Can be administered topically, parenterally - Adjunctive therapy includes protecting animals from LIGHT
o Housing indoors or eye patches
How do you control Moraxella bovis in cattle?
- Fly control may help
- NO effective vaccine available
What does Chlamydia psittaci cause in birds?
- Psittacosis
What are the clinical signs of psittacosis in birds?
- Nasal and ocular discharges
- Conjunctivitis
- Green-yellow feces
- Inactivity
- Weight loss
- *diffuse fibrinous airsacullits and pericarditis
In acute lesions there may be more profound gross and histological lesion of psittacosis in birds
- Hepatomegaly
- Serofibrinous polyserositis
- Petechial hemorrhages on liver and spleen
How is Chlamydia psittaci in birds transmitted?
- Fecal-oral
- Vertical