Difference between revisions of "Campylobacter jejuni"
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(Created page with '===''Campylobacter jejuni''=== *Widespread on farms - hyperendemic *Carried as commensals in intestines of cattle, sheep…') |
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*Usually asymptomatic infections in chickens and turkeys, but occasional outbreaks of avian hepatitis occur with decreased egg production, loss of condition, haemorrhage and necrosis of liver; phase contrast microscopy demonstrates curved rods in bile; in-feed dihydrostreptomycin sulphate in outbreak | *Usually asymptomatic infections in chickens and turkeys, but occasional outbreaks of avian hepatitis occur with decreased egg production, loss of condition, haemorrhage and necrosis of liver; phase contrast microscopy demonstrates curved rods in bile; in-feed dihydrostreptomycin sulphate in outbreak | ||
*Implicated in [[Intestines Catarrhal Enteritis - Pathology#Undifferentiated Neonatal Calf Diarrhoea|undifferentiated neonatal calf diarrhoea]], a mixed viral enteritis in calves[[Category:Campylobacter_species]][[Category:Dog]][[Category:Cattle]][[Category:Sheep]] | *Implicated in [[Intestines Catarrhal Enteritis - Pathology#Undifferentiated Neonatal Calf Diarrhoea|undifferentiated neonatal calf diarrhoea]], a mixed viral enteritis in calves[[Category:Campylobacter_species]][[Category:Dog]][[Category:Cattle]][[Category:Sheep]] | ||
| + | |||
| + | * An important enteropathogen of man and a number of animal species. | ||
| + | * The largest cause of food-poisoning in the UK. | ||
| + | ** Is therefore a public health issue. | ||
| + | * Very widely distributed on the farm- carried in the intestinal tract of: | ||
| + | ** Cattle | ||
| + | ** Sheep | ||
| + | ** Dogs | ||
| + | ** Chickens | ||
| + | ** Wild birds | ||
| + | * Widespread distribution on the farm means that it is hyperendemic. | ||
| + | ** All animals are regularly exposed to it by the faecal oral route. | ||
| + | ** Passive (colostral) protection is helpful while active immunity develops. | ||
| + | * There is no regular exposure in the hygienic environment of the human or pet dog. | ||
| + | ** These animals are much more susceptible to infection. | ||
| + | * The intestinal contents of the broiler chicken may be spread around the abdominal cavity at slaughter. | ||
| + | ** Most poultry is moderately or heavily contaminated. | ||
| + | *** If frozen chicken is inadequately thawed, bacteria may remain viable in the abdominal cavity. | ||
| + | *** Bacteria may be ingested by humans handling the raw meat. | ||
| + | |||
| + | ====Pathogenesis==== | ||
| + | |||
| + | * Bacteria colonise the gut, attach to and invade the mucosa, and produce toxin. | ||
| + | * Causes colitis, characterised by: | ||
| + | ** Necrosis of absorptive epithelial cells | ||
| + | ** Erosion of the mucosa | ||
| + | ** Crypt abscesses | ||
| + | ** Infiltration of inflammatory cells into the mucosa. | ||
| + | *** Primarily [[Neutrophils - WikiBlood|neutrophils]]. | ||
| + | * Functional flagella are important as virulence factors. | ||
| + | ** Non-flagellate campylobacter do not colonise in vivo, and are less invasive in vitro. | ||
| + | * Diagnosed by laboratory diagnosis. | ||
Revision as of 21:34, 10 May 2010
Campylobacter jejuni
- Widespread on farms - hyperendemic
- Carried as commensals in intestines of cattle, sheep, dogs, wild birds and especially chickens
- Farm animals regularly exposed via faecal-oral route; maternal antibody protects while active immunity develops
- Animals with little exposure are very susceptible, e.g. humans, pets
- Most chicken carcasses contaminated, leading to food poisoning and enterocolitis in people from uncooked meat
- Colonisation, attachment and invasion of colonic enterocytes; toxin production
- Necrosis of colonic absorptive epithelial cells, erosion of mucosa, crypt abscesses, inflammatory infiltrate of neutrophils into mucosa causes colitis
- Enteritis and diarrhoea in susceptible dogs; treatment with enrofloxacin
- Causes abortion in ewes
- Usually asymptomatic infections in chickens and turkeys, but occasional outbreaks of avian hepatitis occur with decreased egg production, loss of condition, haemorrhage and necrosis of liver; phase contrast microscopy demonstrates curved rods in bile; in-feed dihydrostreptomycin sulphate in outbreak
- Implicated in undifferentiated neonatal calf diarrhoea, a mixed viral enteritis in calves
- An important enteropathogen of man and a number of animal species.
- The largest cause of food-poisoning in the UK.
- Is therefore a public health issue.
- Very widely distributed on the farm- carried in the intestinal tract of:
- Cattle
- Sheep
- Dogs
- Chickens
- Wild birds
- Widespread distribution on the farm means that it is hyperendemic.
- All animals are regularly exposed to it by the faecal oral route.
- Passive (colostral) protection is helpful while active immunity develops.
- There is no regular exposure in the hygienic environment of the human or pet dog.
- These animals are much more susceptible to infection.
- The intestinal contents of the broiler chicken may be spread around the abdominal cavity at slaughter.
- Most poultry is moderately or heavily contaminated.
- If frozen chicken is inadequately thawed, bacteria may remain viable in the abdominal cavity.
- Bacteria may be ingested by humans handling the raw meat.
- Most poultry is moderately or heavily contaminated.
Pathogenesis
- Bacteria colonise the gut, attach to and invade the mucosa, and produce toxin.
- Causes colitis, characterised by:
- Necrosis of absorptive epithelial cells
- Erosion of the mucosa
- Crypt abscesses
- Infiltration of inflammatory cells into the mucosa.
- Primarily neutrophils.
- Functional flagella are important as virulence factors.
- Non-flagellate campylobacter do not colonise in vivo, and are less invasive in vitro.
- Diagnosed by laboratory diagnosis.