Nonsurgical GI - Diarrheal Disorders Flashcards by Agata Grzelak

Bovine virus diarrhea virus - what kind is it?

Pestivirus RNA virus

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Two biotypes of BVDV

Cytopathic - kills cells

Noncytopathic - does not kill cells

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Genotypes of BVDV

Type I: A and B

Type II

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BVDV has a high ____ diversity and a high rate of _____.

Antigenic; mutation

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Pathophysiology of BVDV

Contact with infected excretions/secretions
Virus is taken up by reticuloendothelial cells
Replication in lymphocytes and macropahges

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BVDV leads to viremia in which three organ systems:

GIT, respiratory tract, and reproductive tract

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C/S of bvdv

Most often subclinical infection

May see:

Diarrhea +/- blood, fever, decreased feed intake, decreased milk production, orla erosions

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The more virulent type of BVDV is what genotype?

Type II - increased severity of clinical signs, significant mortality

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Why does BVDV cause hemorrhage - petechia, ecchymosis, bleeding from injection sites, bloody diarrhea, and epistaxis?

Destruction or sequestration of platelets

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Immunosupression caused by BVDV leads to:

Transient leukopenia/lymphopenia
Altered T and B lymphocyte function
Altered neutrophil function
Altered monocyte/macropahge function
Decreased resistance to secondary infections

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Between what days of gestation will a fetus develop persistent viremia b/c their immune system will recognize the virus as self (immunotolerant?

80-100 days- needs to be a non-cytopathogenic virus

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Available tests for BVDV:

Virus isolatio and PCR - look for antigen
Serology - looks for antibody against BVDV
IHC of skin biopsy
Antigen capture ELISA - a serum test looking for antigen

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Mucosal disease with BVDV in PI calves occurs when the PI calf is exposed to a cytopathic virus that is _______ similar to the noncytopathic virus that the calf is infected with.

antigenically

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When a PI calf with BVDV is exposed to a cytopathic virus that is antigenically similar to the noncytopathic virus, what happens to the calf?

Overwhelming viremia, severe clinical signs, and even death because the calf does not even mount an immune response becuase the calf does not recognize the virus as foreign because it is so antienically simliar to the noncytopathic virus that it was originally infected with during gestation (80-100 days of gestation).

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Calves which nurse BVDV seropositive cows will have ____ titers, reardless of infection status.

Positive

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Which tests will be positive in an acutely infected animal with BVDV?

Only virus isolation/PCR (too early to mount an immune response to show up on serology)

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When do we see a BVDV positive IHC on a skin biopsy?

Only in a persistently infected cow

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Control measures of BVDV

Remove PI cattle

Whole herd screening when entire herd is open becuase you may have pregnant cow harboring a persistent calf if the whole herd is not open.

MLV vaccines - PRIOR to infection

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MC transmission of salmonellosis

Fecal-oral - cow eating fecal material

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Most salmonellosis infections present as ______.

subclinical

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MC species of salmonella - serovar B (2)?

What is the most common host?

S. typhimurium and S. agona

Found in ALL species

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MC salmonella species - serovar C?

Most common hosts?

S. newport

Cattle and sheep

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MC salmonella serovar D?

MC host?

S. dublin - cattle

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What species of salmonella is shed in in milk?

S. dublin (serovar D)

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C/S of Salmonellosis

Most are subacute. If they do show C/S, they include: Septicemia (fever, anorexia) acute enteritis (bloody, mucus dairrhea with casts; dehydration) and rarely chronic enteritis

Definitve diagnosis of salmonella

Microbiological isolation from tissue samples

Practical dx of salmonella

Characteristic clinical signs + positive fecal culture should be enough for you to treat for salmonella, even though the dairrhea may not be due to salmonella, it most likely is.

T/F: it is improtant to treat carriers of salmonella.

False

Tx of clinical disease in salmonella

Appropriate antibitoics (gram negative spectrum) - Ceftiofur Anti-inflammatory agents Fluid therapy/acid-base Cull

While winter dysentery has an undertermined etiology, what is the suspected cause of it?

Coronavirus

C/S of winter dysntery

Fever **Fulminate diarrhea (dark/bloody, rapid spread)** **Respriatory signs** Decreased milk production

Winter dysentery is most sever in ____ adults, but absent in \_\_\_\_\_.

Young adults; absent in youngstock

Clinical course of winter dysentery? When does herd outbreak resolve? Mortality?

Clinical course = 3 days Herd outbreak resolves within 2 weeks High morbidity but NO mortality!

Another name for M. avium ssp paratuberculosis infection?

Johne's Disease

*Mycobacterium avium ssp. paratuberculosis* is an ___ fast organism related to TB, leprosy, and M. avium.

acid

M. avium ssp paratuberculosis persists in ____ for up to 1 year. Alkaline ____ have decreased organism survival.

Soil; soil

M avium ssp paratuberculosis resists pasteurization at ___ degrees C for ___ minutes.

63; 30

Host range of M. avium ssp. paratuberculosis

Cattle, sheep and goats other feral and domestic ruminants occasionally in camelids

Most common route of transmission of M. avium spp paratuberculosis?

Fecal-oral

Can M. avium ssp paratuberculosis be transmitted transplacentally and sexually?

Yes

MC age of M. avium ssp paratuberculosis infection?

Neonates - does not mean they develop C/S - simply pick up the organism at an early age

Vast majority of animals will pick up M. avium ssp paratuberculosis within the first ___ months of life.

M avium ssp paratuberculosis is more common in dairy or beef cattle?

Dairy

Stage 1 infection of M. avium ssp. paratubuerculosis

Silent - no clinical signs and no ill effects, generally seronegative, may be culture positive

Stage 2 infeciton of M. avium ssp paratuberculosis

Subclinical - potential, mildly decreased productivity, often seronegative, 20% culture positive

Stage 3 of M. avium ssp paratuberculosis infection

Clinical disease - decreased production and body coniditon, episodic diarrhea, with normal appetite and often excessive thirst

Stage 4 infection with M. avium ssp paratuberculosis

Advanced clinical disease - emaciation, fluid diarrhea, +/- edema, weakness

For each animal in stage 3 infeciton with M. avium ssp paratuberculosis, expect at least _______ animals in stage 2 and stage 1 infection.

16 - 25

Peak incidence of M. avium ssp paratuberculosis

3-5 years of age

C/S of M. avium ssp paratuberculosis rarely occur before ___ years of age.

Common C/S in cattle with M. avium ssp paratuberculosis infection

Chronic progressive weight loss Excellent appetite! Calving often precipitates C/Ss Singular animals ill at any time Diarrhea - itnermittent progressing to persistent**, watery wihtout blood or casts** **I**ncreased external parasite burden Dependent edema, bottle jaw.

T/F: Cows showing C/S of M. avium ssp paratuberculosis infection have a poor appetite.

False - they have an excellent appetite despite signs of weight loss

What kind of diarrhea is MC in cattle infected with M. avium ssp paratuberculosis showing clinical signs?

Watery WITHOUT blood or casts

C/S of M. avium ssp paratuberculosis in sheep?

Chronic weight loss diarrhea is RARE

MC tests used to dx M. avium ssp paratuberculosis

Serology - ELISA (worry about false negatives and positives with subclinical animals) - trust serology in clinical animal Fecal culture Fecal PCR

Two types of fecal cultures used to test for M. avium ssp paratuberculosis? What are the differences?

Herrold's egg yolk fecal culture - takes up to 16 weeks to dx negative; better test for sheep TREK liquid media - only takes a couple weeks for positive to show up

What is the best test to dx M. avium ssp paratuberculosis in sheep?

Serology - ELISA

Eosinophilic enterocolitis presents similarly to which disease?

Johnes disease - M. avium ssp paratuberculosis

Eosinophilic enterocolitis is a _____ diarrhea.

malabsorptive

Tx for eosinophilic enterocolitis:

Steroids

Why is it improtant to take a biopsy dx for eosinophilic enterocolitis before tx with steroids?

B/c johnes disease will also respond to steroids but then become much worse - so we need to be sure the animal does not have Johnes disease