Avian salmonellosis Flashcards
What salmonella species are host-specific?
typhoid: salmonella pullorum, salmonella gallinarum
paratyphoid salmonellosis is important to the poultry industry because:
food safety concerns
What is pullorum disease
infectious EGG TRANSMITTED disease of poultry, esp chicks and tuurkey poults, characterized by white diarrhea and high mortality in young birds and by asymptomatic adult carriers
Who does pullorum disease usually occur in?
young chicks and turkey poults. Disease in all age groups but greatest loss
Why was pullorum disease important historically?
the losses from the disease were so severe they impaired expansion of the poultry industry
What did the poultry industry do to address pullorum disease?
devleoped an improvemnet plant that allowed them to control hatchery disseminated disease. It is now eradicated fromm commercial poultry in US but is still in back yard flocks
What is teh cause of fowl typhoid?
salmonella gallinarum
How long can salmonella pullorum be present in the environment?
months (but can be killed with cleaning and disinfection)
How is salmonella pullorum primarily spread?
- through infected eggs laid by carrier hens, which then transmit the organism laterally in the hatchery.
- Adults can also have slow lateral spread. Contamination of eggs–penetration can also occur
- cannibalism
What are the signs of s. pullorum in adults?
none. Ma appear unthrifty
What are the signs of s pullorum in young chicks and poults?
- reduced hatchability
- early death
- batermia
- rise in morbidity/mortality around 4th, 5th day–weak, anorexia, adherent white diarrhea
mortality may be very high or relatively low
What are the lesions of s. pullorum in adults?
often none. may have abnormal gonads or myocarditis, pericarditis
What are the lesions of S pullorum in young chicks and poults?
- no signs
- feel wet
- white feces
- grey nodules on multiple sites
- petechial hemorrhags
- swollen joints
. white plaques on intestine - spleen frequently enlarged
How is pullorum disease diagnosed?
- history
- signs
- in young chicks and poults
- serology from surviving birds
- isolation of s. pullorum
How is s. pullorum controlled
maintenance of pullorum-free breeder and multiplier flocks by serological testing
What is paratyhoid infection?
an acute or chonic disease of poultry, many other birds, and mammals caused by one of a large group of salmonellae that are not host secific
What age group is most severely affected with paratyphoid?
the young
What are two speccies of salmonella that cause paratyphoid?
enteridis, typhimurium
What is responsible for the pathogenic effects of paratyphoid salmonellosis?
endotoxin
Where do paratyphoid organisms often localize to?
the intestine or gallbladder of carriers
How does infection of young birds occur?
fecal contamination of egg shells and penetration into eggs
How do carriers shed paratyphoid salmonella?
in the feces
Does vertical transmission occur with paratyphoid salmonella?
yes. The paratyphoid organisms can localize to the ovary and result in transovarian transmission
What non-poultry species is a reservoir for paratyphoid salmonella?
rodents
