Difference between revisions of "Category:Spirochaetaceae"

Revision as of 22:27, 14 May 2010

<ncl style=compact maxdepth=2 headings=bullet headstart=2 showcats=1 showarts=1>Category:Spirochaetaceae</ncl>

Borrelia

Brachyspira and Serpulina

Anaerobic, intestinal spirochaetes, found in normal and diseased pigs
Enterophogens of pigs
B. hyodysenteriae, B. pilosicoli, B. innocens, Serpulina intermedia and S. murdochii occur in pigs
Carrier pigs shed B. hyodysenteriae for up to 3 months, acting as a source of infection for healthy pigs
Demonstrated in stained faecal smears or silver-stained histopathology sections
Cultured anaerobically on selective blood agar
Spirochaetes differentiated by pattern of haemolysis on blood agar as well as molecular techniques

Pathogenesis
- Motility in mucous allows colonisation of pig intestine
- Haemolytic and cytotoxic activiity important for virulence
- Attachment of B. pilosicoli to epithelial cells of colonic mucosa disrupts their function and leads to their shedding and oedema

Clinical infections
- B. hyodysenteriae causes swine dysentery
- B. pilosicoli causes porcine intestinal spirochaetosis
- Infection is acquired via contaminated faeces
- Disease spreads slowly through the herd
- Dogs, rats, mice and flies may act as transport hosts
- B. hyodysenteriae survives several weeks in moist faeces

Clinical signs
- B. hyodysenteriae causes dysentry in weaned pigs 6-12 weeks old; pigs lose condition and become emaciated; appetite is decreased; large amount of mucous may be present in the faeces; low mortality; poor feed conversion ratio
- B. pilosicoli causes less severe signs than swine dysentry; reduced feed conversion rates occur

Diagnosis
- History, clinical signs and gross pathology
- Anaerobic culture on blood agar with added antibiotics for at least 3 days
- B. hyodysenteriae causes complete haemolysis whereas other spirochaetes cause partial haemolysis
- Immunofluorescence, DNA probes and biochemical tests
- Serology using ELISA can be used on a herd basis
- PCR

Brachyspira hyodysenteriae

Subcategories

This category has the following 2 subcategories, out of 2 total.

B

► Borrelia species‎ (3 P)
► Brachyspira and Serpulina‎ (2 P)

Pages in category "Spirochaetaceae"

This category contains only the following page.

L

Lawsonia intracellularis

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-===''Borrelia''===
+<ncl style=compact maxdepth=2 headings=bullet headstart=2 showcats=1 showarts=1>Category:{{PAGENAME}}</ncl>
-*Longer, wider, helical spirochaetes with a linear chromosome and linear and circular plasmids
+===''[[Borrelia]]''===
-*Obligate parasites transmitted by arthropod vectors
-*Cause systemic infections in many animals and humans
-*Slow growth in specialised culture media
-*Lyme disease
-**Caused by ''Borrelia burgdorferi''
-**Reported in humans, dogs, horses, cattle, sheep
-**Ticks are the vector, which acquire the infection from small rodents, the reservoir hosts
-**Ticks transmit the infection to large mammals such as deer and sheep
-**''Ixodes ricinus'' is the most common tick vector in Europe
-**Pathogenesis
-***Virulence of the borreliae requires a change in expression of an outer membrane protein following ingestion of blood by the tick
-***Borreliae multiply in the blood stream of susceptible hosts and disseminate throughout the body
-***Localisation in joints, brain, nerves, eyes and heart can occur
-***The associated lesions may be in part caused by the host immune response
-**CLinical signs
-***May be subclinical in endemic areas
-***Clinical manifestation depends on the site of localisation of organisms
-***Disease in dogs may cause fever, lethargy, arthritis, cardiac, renal or neurological disturbance
-***Horses suffer similar clinical signs but also lameness, uveitis, nephritis, hepatitis and encephalitis
-***Cattle and sheep may suffer from lameness
-**Diagnosis
-***Laboratory confirmation difficult due to low numbers of organisms and fastidious growth requirements
-***History of exposure to ticks in an endemic region and clinical signs
-***Rising antibody titre to ''Borrelia burgdorferi'' detected by ELISA
-***Immunofluorescence
-***Culture in Barbour-Stoenner-Kelly medium for 6 weeks under microaerophilic conditions
-***PCR
-**Treatment and control
-***Amoxycillin and oxytetracycline in the acute phase; prolonged treatment in the chronic phase
-***Tick control and removal
-***Vaccines including whole cell bacterins and recombinant subunit vaccines available for dogs
-===Avian spirochaetosis===
-*Caused by ''Borrelia anserina''
-*Acute, endemic disease of birds in tropical and subtropical regions
-*Chickens, turkeys, pheasants, ducks and geese susceptible
-*Transmitted by soft ticks of the ''Argas'' family, but also via contact with infected material such as blood and tissues
-*Transmitted transovarially and trans-stadially via the tick population
-*Outbreaks during peak tick activity during warm, humid conditions
-*Fever, anaemia and wight loss occurs, with development of paralysis later
-*Immunity is serotype specific
-*Diagnosis using dark-field microscopy of buffy coat smears or immunodluorescence of blood or tissues
-*Giemsa-stained smears and silver impregnation of tissues
-*Isolation of borreliae by inoculation of embryonated eggs or chicks
-*Antibiotic treatment
-*Inactivated vaccines available