when are the three times in life a pig is most likely to get ETEC?
(1) Within the first week of life (3 – 5 days of age) (2) 1-2 weeks post weaning (Edema Dz) (3) At times of high stress (abrupt change in environment or diet)
why does ETEC cause edema in edema dz?
caused by the TOXINs of the ETEC
what is the etiological agent of ETEC? (say a little about it)
Gram-negative, flagellated bacilli. Pathogenic strains form smooth to mucoid colonies. Some are beta-hemolytic
what is it that allow bacteria (like ETEC) to attach & colonize the enterocytes of the small intestine?
Fimbria, which are Small hair-like processes
what do pathogenic strains of ETEC have in common?
they produce one or more enterotoxins
do enterotoxins have systemic or local effects?
Both actually! they are elaborated locally in the sm int tho
what are the 5 common, distinct pili types found in pigs?
F4 (K88), F5 (K99), F41, F6 (987P) & F18
which 3 pili types Mediate adhesion to enterocytes in neonatal pigs?
F5 (K99), F41, F6 (987P)
which pili type is not associated with neonatal colibacillosis but is common in post weaning colibacillosis?
which pili type can be associated with neonatal or post weaning colibacillosis? ( Attaching & Effacing E. coli)
what are the 4 main types of enterotoxins produced by ETEC?
Labile toxin (LT),Stable toxin A (StA), Stable toxin B (StB), Verotoxin (shiga-like toxin, SLT)
which enterotoxins act locally causing hypersecretion?
Labile toxin (LT),Stable toxin A (StA), Stable toxin B (StB)
which enterotoxin is Responsible for the systemic vascular effects of edema disease?
Verotoxin (shiga-like toxin, SLT)
which type of diarrhea does ETEC cause?
secretory (bc toxins) (doesnt cause enough damage to be malabsorptive)
explain the pathogenesis of ETEC and how it causes diarrhea
E coli adhere to the microvili--> they colonize/prolif and elaborate enterotoxins--> excessive secretion of fluids and electrolytes (Damage to the microvilli & enterocytes --> Reduced absorption. ALSO Damaged epithelial cells may lead to septicemia), +/- Large intestine --> Impaired absorption --> diarrhea. Secretion exceeds absorptive capacity Net flow of fluids into the intestinal lumen= ***SECRETORY DIARRHEA
ETEC usually is causing ___ type diarrhea in pigs ____ (age)
Hypersecretory diarrhea in pigs < 5 days
what is the pH/appearance of ETEC diarrhea?
Feces has alkaline pH (Loss of HCO 3- ) (**SO alkaline poop but they have metabolic acidosis). The poo can vary in color (can be white or yellow, can be clear and watery, esp in neonates) but there will not be blood (hypersecretory means not much damage to vili to cause bleeding)
CSs of ETEC?
HYPERSECRETORY DIARRHEA (esp if <5d old), dehydration, rough coat, hypothermia (shivering), death losses can be severe.
2 ways to dx ETEC? (wont ask about dx he said)
Feces & Small intestine for ID, culture & sensitivity. PCR, IFA
what are some things you can do for supportive care of ETEC?
Extra bedding, heat sources, free choice water and electrolyte solutions.
how does the pig's body change if they survive the ETEC?
With time, next set of enterocytes will grow, and New enterocytes will lack receptor for attachment of ETEC. May results in self cure IF hydration can be maintained
what should you keep in mind when providing fluid to ETEC infected pig due to hypersecretory diarrhea?
NOT FREE WATER. They are losing electrolytes too. Free water will lead to cerebral edema
what route of admin of abx for tx of etec DIARRHEA?
ETEC infection is one of the few examples where oral antibiotics are efficacious & justified for treating diarrhea.
what are the two classes (and examples) of drugs you can use to treat ETEC (and route?)
REMEBER-- CAN GIVE ORALLY, THAT IS ACTUALLY BEST. (1) Aminoglycosides (gentamycin, neomycin) actually very desireable bc if given orally will not be absorbed from GI (2) Aminopenicillins (ampicillin, amoxicillin)
the best ways to control/prevent ETEC are?
Hygiene! SANITATION IS #1 (All-in, all-out facility, Clean & Disinfect, Wash the sows Prior to moving them into the farrowing unit, Personnel should practice good biosecurity habits). Immunize sows pre-partum, Single source for breeding stock, Acclimation of breeding & gestation groups 3-6 wks prior to breeding & during gestation, Feed farrowing house waste during late gestation.
is there a vx for ETEC?
yes- immunize sow prepartum
how much time should you give breeding/gestation groups to acclimate to help with this prob?
****once again what kinda diarrhea does this cause?
how is the intestinal wall itself affected by ETEC?
Pure ETEC infections result in little to no inflammatory response within the intestinal wall, bc Organisms do not invade the epithelial cells nor penetrate to the deeper layers of intestinal wall. (most probs bc of toxins). Rarely septicemia or toxemia may result
VIRUS (not in notes on this slide at least but internet says it's a corona)
TGE is most common to affect what age?
Most common in pigs < 2 wks of age. (neonates/young pigs)
what is the seasonality of TGE?
Outbreaks are more common in fall & *****WINTER.
what are the two charateristic CSs of TGE?
Diarrhea and *****VOMITING
what is mortality of TGE like?
High mortality in piglets < 2 weeks of age ( dec with age).
An endemic form of the disease has been described-- what is the presentation like, what are the herds affected by this like?
Herds with partial immunity. Herds with concurrent PRCV infection. Less severe signs with much lower mortality.
how labile is TGE?
Virus is labile at about 72° F (22° C) but Stable when frozen. Destroyed by many common disinfectants.
what are some common sources of TGE?
other pigs, flies, ON WIND UP TO ONE MILE, starlings, rodents, truck tires
what is sthing that makes TGE particularly difficult to avoid infecting?
can travel on wind up to one mile
how does TGE virus get into body? Where does it then go?
Pharynx via the oral or nasal route--> swallowed--> Susceptible enterocytes of SI (not said on slide but I assume tips of vili)
how does TGE affect the intestine, and which parts of the intestine are most affected?
Atrophy, Destruction, & loss of function of the intestinal villi. Most noticeable in the jejunum & ileum.
which type of diarrhea goes TGE cause?
MALABSORPTION bc of atrophy and damage of vili--> cant hydrolyze lactose--> osmotic flow of fluids into intestine--> diarrhea, dehydration, death
what are the actual problems which lead to death with TGE?
Death is related to dehydration, metabolic acidosis, & abnormal cardiac function caused by hyperkalemia.
clinical signs of TGE?
Profuse diarrhea, frequent vomiting, rapid dehydration, shivering, Die within one to two days, Pigs infected after 4 weeks of age often survive
TGE usually affects young pigs...what if feeders are infected with TGE?
Feeder pig signs are usually mild except for diarrhea which is profuse & watery with occasional vomiting. (morbidity high mortality low)
you can basically dx TGE based off of hx/CS (what 3 things most identifiable?)
Explosive diarrheal disease accompanied by frequent vomiting and high mortality
3 lab ways to dx TGE? (wont ask about dx he said)
(1) FA on fresh sections or scrapings of the jejunum (2) IHC formalin-fixed sections of jejunum (3) PCR on feces from acutely affected pigs
is there a vx for TGE?
(1) IF NAIVE HERD: Autogenous vaccines – Minced intestines or from affected piglets & Feed to sows (2) NON-NAIVE HERD: Vaccines administered to dams at intervals prior to farrowing. Generally unable to protect a naïve animals.
what determines how severe the diarrhea is going to be?
more villous damage= more severe diarrhea
You know to think "corona virus" if you see what two features?
HIGH DEATHS and VOMITING
if there is a naïve herd, who will TGE affect? Who shows the most severe signs?
In a naïve herd, the virus attacks all ages.Sows & piglets show signs in severe outbreaks.
***Rare in pigs < 1 week of age. --- usually affect pigs 1-3wks old....immunity developed by 6wk age
which part of the intestine does rota affect?
there are 7 antigenically distinct serogroups of rotaviruse. Which affect swine, and which of these is the most common troublemaker?
4 (A, B, C, E) affect swine. A is the most common
how resistant is rota? how can you kill it?
Stable in the environment, Resistant to temperature changes, various pH levels, & most disinfectants. Formaldehyde & chlorine-based disinfectants including Clorox are recommended.
which part of the vili are damaged with rota?
TIPS. therefore malabsorptive
explain the pathogenesis of rota and how it leads to diarrhea
Invasion villus tips --> damage &/or destruction --> Villous atrophy & fusion --> Impaired intestinal function and reduced disaccharidase activity--> Disaccharides accumulate in the intestine --> Osmotic movement of fluid into the intestinal lumen + malabsorption --> Diarrhea
which is more severe, TGE or Rota?
TGE is more severe
what is the pH of rota diarrhea like-- and WHY does it happen that way?
fecal pH tends to be ACIDIC. This is bc Milk nutrients pass into colon-->Nutrients fermented there to organic acids-->Organic acids exert osmotic pull on water-->Water moves from ECF into lumen-->Dehydration results. Many organic acids are absorbed which results in acidosis, and many are passed resulting in acidic feces.
So Rota is malabsorptive diarrhea and has ___(pH) feces. Whereas which one is HYPERSECRETORY, and what pH does this leave the feces?
Rota=malabsorptive=fermentation=acids build up. ETEC=HYPERSECRETORY=secrete bicarb into intestines=alkaline feces
what are the clinical signs of rotavirus?
Yellow to white diarrhea that continues a few days until pigs develop active immunity. You will see fecal staining of the perineum and their feces will be acidic. They will be moderately dehydrated (vomiting rare-- TGE is the big one with vomiting). Variable morbidity, Low mortality
what are the lab diagnostics you can do to help dx rota? (wont ask about dx he said)
EM to ID virus in intestinal contents or villous epithelium, FA or IHC on villous epithelium, PCR or ELISA on fresh feces to detect virus (Shedding is much greater early in Dz process, Virus is gone in 24-48 hours)
what are some ways to reduce the severity of the rotavirus infection?
Electrolytes in drinking water, dry, warm environment, and good nutrition are important in reducing severity.
how can you manipulate the farrowing period to help dec the virus?
Shorter farrowing period will have less build up of virus
why are they losing bicarb in malabsorptive diarrhea? and if they are losing bicarb, why is there feces still acidic?
Bicarbonate loss due to failure to reabsorb pancreatic secretions. However, the non-absorbed food/milk is then fermented in the colon bc it is not absorbed so there is way more acids than the non-reabsorbed bases
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