Swine 2 Flashcards
piglet birth weight
1.5kg
piglet wean weight and age
- Wean: @ 16-28 days (~21 days)
piglet pre-weaning mortality
- Pre-weaning mortality: <8-10%
Diarrhea due to various agents begins at a different time in the pig’s life
The age/timing of the earliest start of clinical signs helps to determine the causal agent
What are the common 5 causes of diarrhea in piglets, and when do they occur?
- Escherichia coli (colibacillosis) (<12 hrs)
- Clostridium perfringens (<12 hrs)
- Swine enteric coronavirus diseases (SECD): PED and TGE virus (2 d)
- Isospora suis (coccidiosis) (5 d)
- Rotavirus (5 d)
is E. coli normally found in the pig GI tract? what two broad categories are there that must be distinguished?
E. coli are normal inhabitants of GIT, therefore pathogenic and non-pathogenic E. coli’s must be distinguished……
Pathogenic E. coli’s of swine:
- ETEC: Enterotoxigenic E. coli
- VTEC: Verotoxigenic E. coli (Edema disease)
- SEPEC: Septicemic E. coli
ETEC – Clinical signs; Severity dependent on:
- Virulence factors of E. coli strain
- Age and genetics of piglet
- Vaccination status of dam
- Environmental factors (temperature, cleanliness, etc)
ETEC – Clinical signs? what portion of litter affected? is the appearance of the diarrhea notable? peractue form signs?
- Single, multiple, or all pigs within the litter affected
- Colour & appearance of feces is not pathognomonic
- Diarrhea, dehydration, weakness, lethargy, death
- Peracute form: death before onset of diarrhea
ETEC – Common clinical signs in newborns
Newborns with severe dehydration, watery diarrhea and high mortality
ETEC – Common clinical signs in older nursing pigs
Older nursing pigs (i.e., still on sow) with creamy, mild diarrhea
* Severity can vary within and between litters
what type of antibodies are very important for E. coli defence? therefore, what condition can cause problems?
Lactogenic antibodies very important- agalactia leads to E coli diarrhea
how many pigs of the litter are typically affected with E. coli diarrhea?
Typically, multiple pigs to entire litter is affected.
difference in diarrhea appearance for day-old pigs vs later with E. coli
In day-old pigs – feces may be clear. Later feces is colour of ingested feed.
ETEC - Pathogenesis
- Adherence to small intestinal mucosa by means of fimbrial adhesins:
- F4 (K88), F5 (K99), F6 (987P), F41
- Colonization of jejunal/ileal mucosa
- Production of 1 or more enterotoxins
> Sta (ST1), STb (ST11) (heat-stable toxin)
> LT (heat-labile toxin) - Secretory diarrhea (alkaline pH)
fimbrial adhesins of ETEC
- F4 (K88), F5 (K99), F6 (987P), F41
enterotoxins of ETEC
- Sta (ST1), STb (ST11) (heat-stable
toxin) - LT (heat-labile toxin)
ETEC – Pathology (PM findings)
- Usually unrewarding
- Dehydration
- Dilated, fluid filled small intestine
- Congestion of SI vasculature
- Dilated stomach, may contain undigested curd
- Venous infarcts on greater curvature
ETEC – Diagnosis & Distinguishing features; on farm
1) History & epidemiology
* Age of earliest onset, gilt litters, severity, status of dams
2) Fecal pH (on farm)
* Secretory diarrhea – alkaline
ETEC – Diagnosis & Distinguishing features; at laboratory
3) Culture & sensitivity
* Gut loop (tied) or rectal swabs from affected pigs
4) Histopathology (fresh gut essential due to epithelial sloughing)
* Live piglets or place gut in formalin within 15 min
* Minimal villus atrophy
5) PCR: expression of fimbria & enterotoxin genes