Bovine Virus Diarrhea Bovine Virus Diarrhea and PI’sand PI’s

Brendan Kraus, DVMBrendan Kraus, DVM

Spur Ridge Vet HospitalSpur Ridge Vet Hospital

Marion, KSMarion, KS

What is BVD?What is BVD?

Bovine Virus DiarrheaBovine Virus Diarrhea 2 Biotypes & 2 Genotypes2 Biotypes & 2 Genotypes A contagious disease transmitted in A contagious disease transmitted in

bodily fluidsbodily fluids Causes a wide range of clinical Causes a wide range of clinical

symptomssymptoms Cause marked suppression of Cause marked suppression of

immune systemimmune system

Biotypes of BVDBiotypes of BVD (Type does not affect immune response!)(Type does not affect immune response!)

CytopathicCytopathic Kills cells in tissue Kills cells in tissue

cultureculture Arises from a virus Arises from a virus

mutationmutation Most common Most common

strain in vaccinesstrain in vaccines

NoncytopathicNoncytopathic Does not change Does not change

culture cellsculture cells Most common Most common

biotype found in biotype found in naturenature

Genotypes of BVDGenotypes of BVD

Type 1Type 1 Original strains of Original strains of

BVD that were BVD that were isolatedisolated

Is included in all BVD Is included in all BVD vaccinesvaccines

*There is *There is somesome cross cross protection with protection with vaccines between vaccines between types 1 & 2types 1 & 2

Type 2Type 2 This type was more This type was more

recently discoveredrecently discovered Hemorrhagic Hemorrhagic

syndrome strainssyndrome strains Is included in most Is included in most

BVD vaccines nowBVD vaccines now

BVD symptomsBVD symptoms

70-90% of infections 70-90% of infections are subclinicalare subclinical

PneumoniaPneumonia FeverFever RhinitisRhinitis DiarrheaDiarrhea Oral and GI ulcersOral and GI ulcers Immune Immune

suppressionsuppression

AbortionsAbortions StillbornsStillborns Birth DefectsBirth Defects

Mycoplasma JointMycoplasma Joint

What is What is PPersistent ersistent IInfection?nfection?

A PI calf is born infected with the virusA PI calf is born infected with the virus This can happen if the dam is a PI animalThis can happen if the dam is a PI animal This can happen if the dam is transiently This can happen if the dam is transiently

infected during pregnancy from another animalinfected during pregnancy from another animal *The virus must be non-cytopathic**The virus must be non-cytopathic*

The calf must be infected between 40-100 The calf must be infected between 40-100 days approximatelydays approximately During this time the calf has no immune system During this time the calf has no immune system

so it recognizes the virus as “self” and never so it recognizes the virus as “self” and never clears itclears it

After this time, the calf’s immune system is After this time, the calf’s immune system is developed enough to fight the virusdeveloped enough to fight the virus

Manifestations of Calves infected in Manifestations of Calves infected in uteroutero

PI calfPI calf (Body does not (Body does not recognize virus)recognize virus)

Virus is always circulating Virus is always circulating in bodyin body

May die soon after birthMay die soon after birth

Many are clinically normalMany are clinically normal

This is the natural This is the natural reservoir of the virus reservoir of the virus

Infected in utero but Infected in utero but not PInot PI (infected around or after (infected around or after day 100)day 100)

Congential defectsCongential defects Skeletal problemsSkeletal problems Dome shaped headDome shaped head Shortened lower jawShortened lower jaw Eye abnormalitiesEye abnormalities Brain defectsBrain defects

AbortionsAbortions

Clinically normal calvesClinically normal calves

Calves that are not killed Calves that are not killed can clear the virus and go can clear the virus and go onon

PI Calves PI Calves

PI calves are more likely to die than PI calves are more likely to die than non-PI calves in the first yearnon-PI calves in the first year PneumoniaPneumonia DiarrheaDiarrhea Poor doerPoor doer Many look and perform like a healthy Many look and perform like a healthy

calfcalf

Pasteurella mult. LungsPasteurella mult. Lungs

Mucosal DiseaseMucosal Disease

This is Highly fatal syndrome in This is Highly fatal syndrome in which the mucous membranes which the mucous membranes become ulceratedbecome ulcerated MouthMouth StomachStomach IntestineIntestine TeatsTeats Coronary bands of hoovesCoronary bands of hooves

Abomasal UlcersAbomasal Ulcers

Mucosal Dz, contMucosal Dz, cont

For mucosal disease to occur a PI calf For mucosal disease to occur a PI calf (noncytopathic) must be (noncytopathic) must be superinfected with a cytopathic strain.superinfected with a cytopathic strain. The more closely related the viruses are The more closely related the viruses are

genetically, the worse the diseasegenetically, the worse the disease When a noncytopathic virus found in When a noncytopathic virus found in

nature mutates to cytopathic & the calf is nature mutates to cytopathic & the calf is exposedexposed

When the PI calf’s own noncytopathic When the PI calf’s own noncytopathic strain mutatesstrain mutates

PI Calf SheddingPI Calf Shedding

PI calves shed the virus their entire lifePI calves shed the virus their entire life Some periods they may shed a lot, and Some periods they may shed a lot, and

others not as muchothers not as much Virus shed in saliva, tears, urine, feces, Virus shed in saliva, tears, urine, feces,

bloodblood There is so much virus shed, that most There is so much virus shed, that most

vaccines cannot protect other cattle vaccines cannot protect other cattle against a PIagainst a PI

Continue to infect cow herds and create Continue to infect cow herds and create more PI’smore PI’s

PI DiagnosisPI Diagnosis

Ear Notch ElisaEar Notch Elisa Ear Notch ImmunohistochemistyEar Notch Immunohistochemisty Polymerase Chain ReactionPolymerase Chain Reaction Virus IsolationVirus Isolation

These tests can be done at anytime in a PI’s life and only These tests can be done at anytime in a PI’s life and only need to be done once. If positive, will always be need to be done once. If positive, will always be positive. If negative, can be infected with BVD but will positive. If negative, can be infected with BVD but will not be a PInot be a PI

If transiently infected, some tests may be positive, but the If transiently infected, some tests may be positive, but the calf may need to be tested again in a month to confirm calf may need to be tested again in a month to confirm PI statusPI status

BVD ControlBVD Control& Prevention& Prevention

Vaccination with a vaccine using Vaccination with a vaccine using Type 1 and Type 2 strainsType 1 and Type 2 strains

Modified live vaccine creates a Modified live vaccine creates a stronger, more natural immunity, is stronger, more natural immunity, is cheaper, and less doses requiredcheaper, and less doses required

Newer vaccines have label claims Newer vaccines have label claims that if given to cow pre-breeding can that if given to cow pre-breeding can successfully prevent PI in fetussuccessfully prevent PI in fetus

BVD Control & Prevention, cont.BVD Control & Prevention, cont.

Test herds for PI calves and remove Test herds for PI calves and remove all animals to quarantine**all animals to quarantine** Test all dams of PI calves to see if they Test all dams of PI calves to see if they

are also PIare also PI Test all purchased breeding animals Test all purchased breeding animals

before entry into herdbefore entry into herd

Questions?Questions?