Author, Donkey, Bureaucrats, Administrators
53,803
edits
Changes
Created page with '===Overview=== *Two families exist, ''Category:Leptospiraceae'' and ''Category:Spirochaetaceae'' *''Leptospiraceae'' include the pathogens of the genus ''Leptospira'' …'
===Overview===
*Two families exist, ''[[:Category:Leptospiraceae]]'' and ''[[:Category:Spirochaetaceae]]''
*''Leptospiraceae'' include the pathogens of the genus ''Leptospira''
*''Spirochaetaceae'' include the pathogens of the genera ''Borrelia'', ''Brachyspira'' and ''Treponema''
*Many cause zoonotic infections
===Characteristics===
*Spiral or helical Gram-negative bacteria
*Motile organisms via endoflagella
*Poor survival in the environment and sensitive to dessication
*Stain poorly with Gram stain
*Most require specialised media for growth
*Serology required for identification
===''Borrelia''===
*Longer, wider, helical spirochaetes with a linear chromosome and linear and circular plasmids
*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
===''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 [[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Swine Dysentery|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]][[Category:Gram_negative_bacteria]]
*Two families exist, ''[[:Category:Leptospiraceae]]'' and ''[[:Category:Spirochaetaceae]]''
*''Leptospiraceae'' include the pathogens of the genus ''Leptospira''
*''Spirochaetaceae'' include the pathogens of the genera ''Borrelia'', ''Brachyspira'' and ''Treponema''
*Many cause zoonotic infections
===Characteristics===
*Spiral or helical Gram-negative bacteria
*Motile organisms via endoflagella
*Poor survival in the environment and sensitive to dessication
*Stain poorly with Gram stain
*Most require specialised media for growth
*Serology required for identification
===''Borrelia''===
*Longer, wider, helical spirochaetes with a linear chromosome and linear and circular plasmids
*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
===''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 [[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Swine Dysentery|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]][[Category:Gram_negative_bacteria]]