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3. Food Animal 2 > Salmonella and Winter Dysentery > Flashcards

Salmonella and Winter Dysentery Flashcards

(46 cards)

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1
Q

salmonella family

A

Enterobacteriaceae

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2
Q

how many salmonella serotypes? based on what? named for what?

A
  • 2200 serotypes based on 67 O-antigen (somatic) groups and numerous H-antigens (flagellar), Vi- antigen (capsular)
  • Name: place of isolation
    –i.e. Dublin, Montevideo, etc.
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3
Q

salmonella taxonomy

A

2 types: S. enterica & S. bongori

> S. enterica: 6 subspecies
60% S. enterica enteria

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4
Q

are salmonella serotypes host adapted?

A
  • The majority of serotypes are not-host adapted
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5
Q

three types of salmonella based on host-adaptation

A

– 1. Specific to humans:
* S. typhi and S. paratyphi

– 2. Type adapted to animal hosts (>virulent).
* S dublin in cattle; S abortusequi in horses, S. abortusovis in sheep; and S cholerasuis in pigs.

– 3. Un-adapted serotypes:
* can cause disease in humans and variety of animals. (S. typhimurium)

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6
Q

salmonella prevalence? In Ontario, new zealand, california dairy farms

A

Variable:
* Ontario: Calves in 22% farms shed Salmonella spp.
* New Zealand: 13-15% infection rate in dairy cattle
* California: 75% sampled dairies had evidence of infection

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7
Q

which serotypes of salmonella, in which serogroups, commonly cause disease in cattle?

A

10 serotypes in serogroups B, C, D and E common cause of disease in cattle

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8
Q

in what species are salmonella found?

A
  • Universally in all species
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9
Q

Salmonella Typhimurium isolates from both cattle and humans; how have these changed since the 80’s?

A

in the 80’s, almost 0 in both humans and dairy cattle
> increase in lockstep

Outbreak in dairy herds→human infection

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10
Q

6 most commonly isolated salmonella serotypes from dairy cattle

A

> 5000 isolates:
- Salmonella Dublin (23%),
- Salmonella Cerro (16%),
- Newport (14%),
- Montevideo (8%),
- Kentucky (8%), and
- Typhimurium (4%)
comprised the top 6 most commonly isolated sertotypes

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11
Q

salmonella transmission? environmental survival?

A
  • Direct or indirect contact
  • Infected animals are the source of infection → direct contact (animal-to animal) or by contaminating the environment (feed and water)
  • Can persist prolong periods (several months, even years) in the environment
  • Airborn
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12
Q

how/ where does salmonella survive in a carrier?

A
  • Survive in the phagolysosome of macrophage
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13
Q

types of salmonella carriers, their signs, and do they spread it?

A
  • Active carrier:
    – Shed the organism constantly or intermittently in feces (1 billion organism/day or 1 million/gram feces)
  • Latent carrier:
    – persistent infection (lymph nodes and tonsils) but not shedding
  • Passive carrier:
    – Acquire infection from contaminated environment but infection resolved when removed from that environment
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14
Q

salmonella source, pathogenesis? factors affecting disease and virulence?
(specifically S. dublin)

A
  • May penetrate:
  • Ocular, nasal, oral and intestinal membranes
  • Most often feco-oral transmission
  • Source: contaminated fed, water, contaminated milk
    ()
    S. dublin:
  • Invasion through intestinal wall of ileum and cecum→ mesenteric lymph nodes→???
  • Factor affecting type of disease:
    > Immune status, age, stress, virulence of strain
  • Factors affecting virulence:
    > adhesion-pilli, flagella, cytotoxin, enterotoxin, LPS, inflammatory response
    > S. dublin virulence plasmid mediates systemic infection in cattle by causing macrophage dysfunction
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15
Q

risk factors for salmonella disease

A
  • Challenge dose
  • Immunological status
  • Stress
    > transport, anesthesia/surgery, antimicrobials, food deprivation, parturition
  • Previous exposure
  • Colostrum intake (neonates)
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16
Q

salmonella Clinical findings

A
  • Septicemia
  • Acute enteritis
  • Chronic enteritis
  • Terminal dry gangrene of the extremities
  • Abortion
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17
Q

what animals commonly get septicemia from salmonella? what are the signs?

A
  • Common form in neonates
  • Signs: Depression, toxemia, fever, dyspnea, weakness, nervous signs (incoordination, nystagmus)
  • Diarrhea can occur but not common
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18
Q

what age group commonly gets enteritis from salmonella? what are the clinical findings?

A

– Older calves and adults
– Abortions, polyarthritis (calves), diarrhea (whole blood), agalactia
– Acute protein-losing enteropathy
– Abdominal pain
> Rolling, kicking, treading on feet, crouching, groaning, flank watching

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19
Q

what clinical findings might we see in a case of salmonella causing chronic enteritis?

Study These Flashcards
A
  • With inappetance, reduced weight gain, and unthriftiness (after acute enteritis)
  • Abortions (no other signs)
  • Retained placenta (S. dublin)
  • Terminal dry gangrene (limbs, ears and tail tip)
20
Q

salmonella can cause terminal dry gangrene in calves. what signs will we see?

Study These Flashcards
A
  • Lameness
  • Swelling
  • Skin sloughing of limbs

Also: * Endarteritis

21
Q

Nature of salmonella abortions: are salmonella abortions always accompanied by other signs?

Study These Flashcards
A

Can occur spontaneously with no other signs of salmonellosis (S. dublin)

22
Q

salmonella morbidity and mortality (calves and adults)

Study These Flashcards
A

Morbidity:
* 50% in calves
* 14-60% in cattle herds

Mortality:
* High in young calves (<12 weeks)
* 0-14% in adult cattle

23
Q

salmonella CBC findings

Study These Flashcards
A
  • Leukopenia
  • Neutropenia
  • Severe degenerative left shift
24
Q

salmonella Serum biochemistry profile

Study These Flashcards
A
  • Marked hyponatremia
  • Mild hypokalemia
  • Hypoproteinemia
25
slamonella antimicrobial susceptibility: what does it look like, how can it change over time?
- generally quite a bit of resistance >eryt, gent, TMS, Ampi, Rifa, chlor, pen neom > enro is intermediate - susceptible to tetra, some also to ceft, amik >generally, can aquire and lose resistances over time based on antimicrobial use
26
general diagnostic methods for salmonella
* Culture * Fecal culture * Antigen capture ELISA * PCR * Milk bulk tank and filters * Serial blood culture () - individual animal fecal culture using enrichment and selective media - composite fecal sampling - salmonella PCR (feces, milk, tracheal or bronchoalveolar lavage fluid) - blood, transtracheal wash, bronchoalveolar lavage, or joint fluid culture when bacteremia is suspected in claves - culture of post mortem samples: gastrointestinal tract, mesenteric lymph node, bile, and lung - environmental cultures - salmonella Dublin enzyme-linked immunosorbent assay: serum or milk
27
Microbiology results - OVC cases of salmonella PM results?
* S. Dublin was isolated in all 5 cases from the lung tissues * The PFGE pattern was indistinguishable among all 5 isolates-OVC cases * Post-mortem examinations were consistent with septicemia in all 5 cases. * All 5 calves had suppurative bronchopneumonia and three also had suppurative enteritis.
28
serology tests for salmonella dublin
* ELISA test on serum or milk to identify S. dublin carriers * IgG to O-antigen * Detect: > uninfected > recently infected recovered > milk-shedding
29
Differential diagnosis for salmonella diagnosis
–Coliform septicemia
30
differential diagnosis for acute enteric salmonellosis
–Coccidiosis –Acute intestinal obstructions –Winter dysentery –Mucosal disease (BVD) –Bracken fern –Otherpoisoning: arsenic,lead,plants
31
differential diagnosis for chronic salmonellosis
* Johne’s disease * Chronic molybdenum poisoning * Massive stomach fluke infections
32
salmonella control; is it easy? why? methods?
* Environmental contamination difficult to control > Survive in dry feces for years * Vaccination > Killed and modified lived - Adverse reaction - Lack of efficacy - outbreak control
33
winter dysentery etiology; what kind of virus? reservoir?
* Bovine coronavirus – Experimentally reproduced – Serologic response * Virus isolated from wild ruminants: – Sambar deer, waterbuck, white-tailed deer
34
winter dysentery tropism
* Tropism for intestinal and respiratory tract
35
uncertainty around winter dysentery etiology
There is uncertainty among some people as to whether coronavirus is the cause of the disease
36
where is winter dysentery found geographically?
* Common in northern climates > Cattle housed from November-April > USA, Canada, Sweden, Germany, France > Also: Israel, Australia, New Zealand
37
what age / group of animals is winter dysentery more common in?
* Common in recently calved milking cows
38
how does winter dysentery generally present in young animals?
* Young animals may develop a mild form of the disease
39
winter dysentery; morbidity and mortality
* Morbidity: 30-59% * Mortality: < 1%
40
transmission of winter dysentery
Transmission: Fecal-oral route > Affected animals or asymptomatic carriers > Highly contagious
41
winter dysentery pathogenesis?
* Virus has tropism for GI and respiratory tract – Mild enteritis of the small intestine – Respiratory disease in adult cattle and pneumonia in calves * Epithelial cells of colon crypts are destroyed by the virus * The mechanism leading to voluminous watery diarrhea is not clear, but may be related to inflammation * Inflammatory mediators may lead to hyper-secretion in the small intestine and large colon
42
winter dysentery; Clinical findings, incubation
* Incubation: 3-7 days * Explosive diarrhea for 4-7 days * Young animals: mild signs * Fever, decreased milk production, short-lasting anorexia, mild loss of body weight * Dark green to black liquid diarrhea () * Nasolacrimal discharge and cough may precede or accompany GI signs * Short course of disease (2-3days) * Some cases develop a more severe form: > Dehydration, weakness, dysentery with or without blood * Some herds production may not return to normal after a prolong period
43
winter dysentery diagnosis methods
* Electron microscopy * ELISA test (fecal samples) * Paired serology testing (8 weeks apart)
44
winter dysentery Differential diagnosis
* BVDV/MD * Coccidiosis * Salmonellosis * Johne’s disease * Dietary * Copper deficiency
45
are fatal cases of winter dysentery common? what would we see? what about on histo?
Fatal cases are rare * Severe hemorrhage * Hyperemia of colonic and cecal mucosa * Frank blood in the lumen of large intestine Microscopically: * Widespread necrosis and degeneration of epithelium of large bowel
46
winter dysentery Treatment / Prevention
* Usually not required * Supportive therapy * Fluid and electrolytes * Some management practices, notably housing animals in stanchions and use of equipment that handles both manure and feed → associated with winter dysentery

3. Food Animal 2 (20 decks)

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