PM Lecture 5: Diarrhea Across Species: Management

Diarrhea is a population signal, not a (blank)

Diagnosis

What do you need to manage with diarrhea?

The host, agent, environment, and operation; not merely the feces

Define outbreak

More cases than expected for that defined population/place/period. Does not require a known pathogen

Risk or attack proportion of diarrhea

New cases divided by animals at risk.

Case fatality proportion

Deaths divided by identified cases

Cohort-specific risk

Compare pens/rooms/sources/age/classes/feed groups

Time to onset

Plot an epidemic curve

Spatial clustering

Map housing and workflow

Step 1 of plan for diarrhea

Classify population level causes of diarrhea as infectious, toxic, nutritional, management-associated, multifactorial

Step 2 of plan for diarrhea

Prioritize differentials using species, age, immune status, onset, morbidity, mortality, fecal character, systemic, illness, and recent population events

Step 3 of plan for diarrhea

Compare how a shared pathogen or pathogen category presents in different host species

Step 4 of plan for diarrhea

Design a population diagnostic plan that specifies the animals, samples, test, timing and interpretation

Putting plan to work: management

1. Recognize a possible outbreak and implement immediate containment before etiologic confirmation.

2. Select individual targeted groups or whole population interventions based on severity, transmission, risk, feasibility evidence and stewardship

3. Construct a practical protocol, but producers, shelter staff technicians, or farm employees can carry out reliably.

Who should you prioritize testing?

Freshly sick/early, untreated, clinically representative animals first

Who/what else should you prioritize testing?

Multiple animals from epidemiologically distinct locations, severely affected animals (systemic/invasive disease), freshly dead animals for complete necropsy, environmental/feed/water sampled if tied to specific hypothesis, control test

Who does mycotoxin testing in feed?

Nutritionist

Avoid solely relying on what when testing

Chronically affected animals

Samples collected after several treatment courses

Pooled samples when the assay has not been validated for pooling

Environmental positives without animal-level clinical correlation

A single multiplex PCR result treated as the final diagnosis

Is a single positive PCR reliable in a population?

No, it's better to have multiple

What method should you use most of the time when testing dogs and cats with diarrhea (especially unresponsive)?

Use fecal float for most cases of diarrhea

What should you test puppies/young dogs for with diarrhea/ADR and shoddy vaccine history?

Parvo test

When should you consider advanced testing for dogs/cats with diarrhea?

When patient is unresponsive to treatments, diarrhea is acting different from usual, if spreading to 10% of more of a population, or with any unexplained deaths

Differential diagnoses for dogs with diarrhea

Parvovirus, canine enteric coronavirus, Giardia, coccidia, Cryptosporidium, Salmonella, Campylobacter, helminths, stress, diet change

Differential diagnoses for cats with diarrhea

Panleukopenia virus (feline parvo), Giardia, coccidia, Tritrichomonas foetus, Cryptosporidium, diet, stress

What else should you consider outside of how diarrhea looks when it comes to small animals?

Intake source, vaccination status, length of stay, housing unit, age, and movement history

Detection of Clostridium genes or Campylobacter does not automatically establish what in small animals?

Causation

What are diarrhea rates in piglets in a well run herd?

Less than 3% incidence and mortality less than 0.5%

What is considered a severe diarrhea outbreak % in piglets herds

Mortality rises to 7% and 100% for individual litters

What are usual diarrhea rates in grower/finisher swine?

If no recent feed changes, diarrhea should be very low level/none

When should you test for diarrhea in grower/finisher swine?

Test when treatments are not effective, if it is rapidly spreading or persistent, if there are wasting pigs/unthriftiness/uneven growth, increased mortality, necropsy driven, when clinical signalment indicates to test

If you get a pig with E. Coli, what is the likely age?

Unweaned piglets (< 1 week) to nursery piglets (>3 weeks)

If you get a pig with Rotavirus, what is the likely age?

Unweaned piglets (< 1 week) to nursery piglets (>3 weeks)

If you get a pig with Swine Enteric Coronavirus, what is the likely age?

Unweaned piglets (< 1 week) to nursery piglets (>3 weeks), Grow/Finish pigs (2-6 months)

If you get a pig with Clostridium (C. Diff, C. Perf. type A/type B), what is the likely age?

Unweaned piglets (< 1 week)

If you get a pig with Coccidiosis what is the likely age?

Unweaned piglets (< 1 week) to nursery piglets (>3 weeks)

If you get a pig with salmonella what is the likely age?

At any age from nursery piglets (>3 weeks) to grow/finish (2-6 months) to early adult (>7 months)

If you get a pig with swine dysentery what is the likely age?

At any age from nursery piglets (>3 weeks) to grow/finish (2-6 months) to early adult (>7 months)

If you get a pig with proliferative enteropathies (Lawsonia) what is the likely age?

Most common in grow/finish pigs (2-6 months) but can be a little before in nursery or after in adult

If you get a pig with Trichuris suis (whipworm) what is the likely age?

Most common in grow/finish pigs (2-6 months) but can be a little before in nursery or after in adult

If you get a pig with Ascaris suum (roundworm) what is the likely age?

Most common in grow/finish pigs (2-6 months) but can be a little before in nursery or after in adult

What should you ask when there are calves with diarrhea

Is it a herd level concern (20% or more salves affected)?

What else should you consider with calves with diarrhea

Calves are not responding to treatment, new signalment for disease

What should you consider with cows with diarrhea?

Increased incidence of deaths, unknown cause, affect on production, recovery

When is E. Coli most common in cows?

2-3 days of age

When is Rotavirus most common in cows?

7-14 days

When is coronavirus most common in cows?

3-36 days

When is Clostridium most common in cows?

0-14 days

When is Cryptosporidium most common in cows?

14-36 days

When is coccidia most common in cows?

21+ days

When is salmonella most common in cows?

Any age

When is nutritional caused diarrhea most common in cows?

Any age

When is BVDV most common in cows?

Any age

E. Coli signs in cattle

Diarrhea, depression, coma

Rotavirus signs in cattle

Watery brown to light green diarrhea with bloody mucus

Coronavirus signs in cattle

Profuse, watery and yellow diarrhea

Clostridium signs in cattle

None in most cases, may include some straining, kicking at abdomen, foul smelling diarrhea containing blood

Cryptosporidium signs in cattle

Watery brown to light green diarrhea with blood mucus

Coccidia signs in cattle

Tarry and often bloody scours

Salmonella signs in cattle

Diarrhea with blood and fibrin, depression, fever

Nutritional diarrhea causes in cattle

Milk or milk replacer fed at inconsistent temperature or improper solid concentration

BVDV signs in cattle

Ulcers on tongue, lips, mouth. Very liquid feces that are yellowish brown to grayish green and may become yellowish gray containing blood and fibrin as disease progresses

When to investigate diarrhea in adult equine

Diarrhea that lasts longer than a day accompanied by fever, lethargy, loss of appetite, colic, dehydration, dry mucous membranes

When to investigate diarrhea in foals

Any sick foal with diarrhea (0-3 months) and especially in breeding operations

What are bacterial diarrhea causes in foals?

E. Coli, Rhodococcus equi, Lawsonia intracellularis, Clostridioides difficile, Salmonella spp., Clostridium perfringens

What are viral diarrhea causes in foals?

Rotavirus A/B, Beta Coronavirus

What are parasitic diarrhea causes in foals?

Strongyloides westeri, Cryptosporidium spp., Giardia

What are non-infectious diarrhea considerations in foals?

Foal heat diarrhea, nutritional intolerance, sand/gravel consumption

What are bacterial diarrhea causes in adult equine?

Potomac horse fever (PHF), Clostrodiodes difficile, Salmonella spp., Clostridium perfringens

What are viral diarrhea causes in adult equine?

Beta coronavirus

What are parasitic diarrhea causes in adult equine?

Cyathostomiasis

What are non-infectious diarrhea causes in adult equine?

NSAID, toxins (blister beetles, arsenic, oak, ionophore), antimicrobial-induced colitis, sand/gravel consumption, neoplasia, inflammatory bowel disease

When to investigate diarrhea in poultry?

Any severe deviation from normal droppings with clinically sick birds (lethargic, ruffled feathers, reduced feed/water intake, egg production down), when more than 1/3 of droppings from a single bird are wet/sticky

Key Performance Indicators for poultry diarrhea

Deviation from mortality rates (5% cumulative general benchmark)

Increased culling

Litter quality (moisture meters, increased ammonia levels)

Appearance of droppings using scoring systems

Diagnostic hierarchy step 1

Immediate population assessment

Immediate population assessment involves what

History, exam, hydration, perfusion assessment

Temperature and systemic illness screening

Morbidity, mortality, onset, location

Feed, water, housing, movement, vaccination, treatment review

Point-of-care tests (where they will change immediate actions)

Diagnostic hierarchy step 2

Etiologic investigation

Etiologic investigation involves what

Fecal PCR/antigen testing for possible viruses/bacteria/protozoa

Fecal flotation, centrifugation, direct smear, organism specific testing

Bacterial culture and susceptibility where systemic disease or a meaningful isolate is suspected

CBC, biochemistry, blood gas, lactate, blood culture in selected systemic patients

Necropsy, histopathology, intestinal contents, fresh/fixed tissues

Types of diagnostics samples

Feces, blood, tissues

Examples of fecal tests with feces sample

Culture (aerobic, anaerobic, salmonella, Johnes)

Fecal (smear, stain)

Fecal flotation

PCR

Examples of tests using blood samples

PCR

Virus isolation

CBC/Chem

ELISA (red top tube)

Which tubes should you use for blood samples

Red and purple

Examples of tests using tissue samples

Smears, cultures, histopath (fixed), virus isolation

Diagnostic hierarchy step 3

Cause

Cause within diagnostic hierarchy contains what

Cohort comparisons and risk-factor analysis

Feed/water testing for specific suspected exposure

Environmental sampling to answer a focused biosecurity question

Repeat/serial sampling for intermittently shed organisms

Isolate typing or genomic investigation when epidemiologically justified

What should you collect premortem when it comes to feces?

2+ grams of feces: must be fresh (hold for 2 days)

Ideally collected prior to treatment

May pool samples in certain cases (contact lab)

When are fecal swabs best?

Some neonates like swine or poultry

Fecal swab instructions

Keep swabs moist (use transport media or saline)

How much blood do you need for send out and what color tubes

2-3ml each tube. Red top and purple top

Amies transport media is used for what

Bacteria

Universal viral transport medium is used for what

Viruses

What can you collect at necropsy?

Feces, blood, fresh tissues, fixed tissues

Examples of fresh tissues to collect at necropsy?

Small intestine, large intestine, spleen, intestinal contents

Examples of fixed tissues to collect at necropsy?

Forestomachs, liver, small intestine, large intestine, mesenteric lymph nodes

Fresh tissue vs fixed tissues

Fresh tissues do not need stained (culture/PCR/toxicology).

Fixed tissues need stained and are formaline fixed

Fecal testing in-house ELISA examples of what to test for

Parvovirus

Giardia

Clostridium. Spp enterotoxin

Cryptosporidium

Fecal testing with fecal cultures examples of what to test for

Salmonella, Campylobacter, E. Coli, Clostridium Spp.

What do you use for fecal cultures?

Special culture transport media

Turnaround time for fecal cultures

3-12 days

Are all things found on a fecal culture concerning?

No, many also present in normal animals

Fecal cultures growth

Heavy pure growth is more significant

Additional PCR panels for feline

Clostridium perfringens enterotoxin A gene

Cryptosporidium spp.

Feline coronavirus (FCoV)

Feline panleukopenia virus

Giardia spp.

Salmonella spp.

Toxoplasma gondii

Tritrichomonas foetus