Episode 16: Diarrheal & Enteric (Intestinal) Dx in Neonates

What is the function of villi?

fingerlike projects that are responsible for the bulk of absorption from the gut

What is the function of the small intestine?

absorption of water, electrolytes, and nutrients from the lumen into the bloodstream

What is the function of crypts?

the “valley” between villi → responsible for the bulk of secretion into the gut

What are two main root causes of diarrhea?

1. Decreased absorption (malabsorption)

2. Increased secretion (hypersecretion)

Why are there 5 types of Clostridium perfringens?

Each type produces a different effect (endotoxins) in different ages and production classes of animals.

What are the main viral causes of diarrhea?

1. Rotavirus = more common

2. Coronavirus = more severe

What is the reservoir for bovine rotavirus and bovine coronavirus?

digestive tract of cattle

True or False: Rotavirus and Coronavirus will survive in the environment for weeks to months.

True

What is the tissue preference for Rotavirus and Coronavirus?

• Rotavirus → tip of villi

• Coronavirus → tip & sides of villi

What is the pathogenesis of Rotavirus and Coronavirus?

1. immature epithelial cells migrate up from the villous crypts

2. Diminished absorption of nutrients coupled w/ the continuing secretion of fluids from the crypt cells results from osmotic diarrhea due to the accumulation of lactose & carbohydrates in the gut lumen

3. acts as an endotoxin which further interferes w/ the ability of epithelial cells to absorb nutrients

4. loss of protective covering of the epithelium gives secondary bacterial pathogens a good foothold to colonize the gut surface

What is the age of onset of Rotavirus and Coronavirus?

• Rotavirus → age of onset: 3 days - 3 weeks

• Coronavirus → age of onset: 1-3 weeks

True or False: Escherichia coli strains are commonly found in the gut of people and animals are most are not pathogenic.

True

True or False: Clostridium perfringens is a gram-negative, spore-forming aerobic bacteria.

False: Clostridium perfringens is a gram- positive, spore-forming anaerobic bacterium.

What makes E. coli unique?

Virulence factors:

• capsule

• pilus antigens

• enterotoxins

What is the pathogenesis of E. coli?

True or False: Type A Clostridium is considered by many to be normal gut flora in animals.

True

What is Type A Clostridium associated with?

• abomasal bloating

• ulcers

• in young calves (2 weeks - 2 months of age)

Which Clostridium type secretes beta-toxin?

Type C

Which Clostridium type is associated with blood scours that leads to sudden death?

Type C

Clostridium type C is almost never implicates as a cause of disease in calves older than _____ days.

7 days

Which two protozoa of Cryptosporidium are common in causing scours in calves?

1. Cryptosporidium parvum → common species affecting calves (zoonotic)

2. Cryptosporidium hominis → only affects people (common w/ waterparks & swimming pools)

True or False: Cryptosporidium is extremely hardy in the environment and resistant to disinfectants.

True

What is the age of onset for Cryptosporidium?

1 week - 1 month

What is the pathogenesis of Cryptosporidium?

Which coccidiosis affects cattle?

Eimeria bovis

What is the pathogenesis of Coccidiosis?

• calf ingests oocysts

• Infective forms invade intestinal epithelial cells

• extensive damage to intestinal lining

Is it important to identify specific agents in a scours outbreak?

• Yes

  • some agents need certain treatments

  • vaccination of cow herd

• No

  • exposure patterns are the same regardless of agent

  • treating dehydration is important regardless

  • many infections involve> 1 agent

List the clinical signs and effects of scours in neonatal calves.

• Dehydration: sucken in eyes, decrease skin tent, weakness

• Acidosis: abnormally low blood pH

• Electrolyte disturbances: result in a depletion of potassium in cells

• Depression: loss of ability to nurse

• Hypothermia: temp <100F

List the goals of tx for fluid therapy in diarrheic calves.

1. Correcting dehydration, restoring blood volume in the process

2. Correcting metabolic acidosis

3. Correcting electrolyte abnormalities

4. Correcting energy deficits

What are the reasons for using antibiotics in treating scouring calves?

30% of 10-day old scouring calves are bacteremic

List principles of feeding calves milk replacer that reduce risk of digestive problems.

1. meticulous attention to proper milk replacer mixing

2. feed at body temp of 102F

3. feed at the same time every day

4. make changes gradually

What is the onset of scours?

• Rotavirus: 5 -14 days

• Coronavirus: 7 - 21 days

• Crypto: 7 - 28 days

• Coccidiosis: 28 days and up

• ETEC, C. perfringens Type C: 0-14 days (usually 0-5)

True or False: Acidosis of the blood can correct well with dehydration.

False

In oral calf electrolyte preparations, which ingredient does the best job of alkalinizing a calf’s system? (combat acidosis)

acetate

True or False: You should feed electrolytes and milk replacer one after another.

False: Separate milk and electrolytes feedings by 2-3 hrs if possible.

What combination proves water and alkalinization will combat both dehydration and acidosis?

isotonic sodium bicarbonate

What oral antibiotics should be avoided to tx scours?

• sulfa pills

• tetracycline (CalfSpan) boluses

Why might probiotics make scours worse in calves?

young calves are not yet ruminants → many of these products are beneficial in older animals for various indications

Other than rehydration, providing an energy source, and potential use of antibiotic, what are other possible diarrhea treatments?

• NSAID (Banamine)

• B-Vitamins

What product has Vitamin B in it?

NurseMate ASAP

What are some host factors that affect susceptibility to calf scours?

1. Passive Immunity: colostrum

2. Age

3. Maternal nutrition