| Line 1: |
Line 1: |
| − | ===''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
| |
| | | | |
| | | | |