Early Embryonic Loss and Abortion

What is Tritrichomonas foetus?

Protozoa disease that is venereally transmitted

What are the economic losses of trich?

Will cause lots of early abortion

What are the C/S of trich?

No systemic disease, just see a low pregnancy rate

Can cause pyometras and abortion

What are the C/S of trich in bulls?

Colonizes prepuce and penil folds, no approved and effective treatment

Will not clear disease unless young but maybe can but rare

What happens when cows are infected with trich?

Exposure to infected bull at coitus causes no immediate failure and pregnancy will progress until 70-90 days into gestation

Will clear infection in 2-22 months but will not become immune

Can remain infected through pregnancy

What does vaccination for trich do?

Doesn’t prevent infection but might make abortion less likely once infected

Is not given to bulls

What is the epi of trich?

Rare but has a large impact

Is present worldwide

T/F trich is reportable?

True

What is the reservoir for trich?

Bulls without symptoms and cows

How do you diagnose trich?

Bull: smegma

Female: discharge or mucus but not as good

Can culture it but PCR (grow it in a culture first) is more common

What is the sensitivity of PCR for trich diagnosis?

Not very good in 1 test need to repeat it 6 times for gold standard rule out

3 negatives is good for production

What media is used for trich?

InPouch TF. Cant be too hot or cold and needs rapid shipment to lab

Saline can be used in Kansas

What happens to bulls if they might have trich?

If positive cull

Retest bulls 3 times prior to breeding season

Test all imported bulls 3 times before breeding

What do you do to positive cows for trich?

Not pregnant cows are sold

Control breeding and pregnancy test

Cull cows that has a Trich abortion

Cull pyometra cows

Biosecurity is much more important

Can vaccinate to reduce risk of impact

What is sensitivity>?

Proportion of true positives that test positive

What is specificity?

Proportion of true negatives that test negative

What is the sensitivity and specificity of trich testing?

Low sensitivity (false negatives common)

High specificity (false positives rare)

What is vibriosis very similar to?

Basically same thing as trich caused by Campylobacter

How is Vibriosis ss. fetus transmitted?

Fecal oral but vaccine is effective

What is leptospirosis?

Zoonotic bacterial disease that causes pregnancy wastage in the last trimester

Causes latent kidney infections

How is lepto transmitted?

Through mucous membranes

Abraded or water soften skin

Possible also sexual contact

Urine contaminated water holes

Describe serovars in lepto

Lots of them each serovar is adapted to a host

That host is the maintenance host with high susceptibility to infection with endemic transmission but low pathogenicity and high chronicity

What is the efficacy of lepto vaccination for host adapted strain?

Very bad

Describe incidental lepto hosts?

Low susceptibility but higher pathogenicity

Vaccination also works vetter

What lepto serovars cause abortion the most in cattle?

Hardjo (maintenance host is cattle)

Pomona (maintenance host is pigs)

What are the problems with diagnostics for lepto?

Hard to prove as cause of abortion especially hardjo

Carriers have low titers

What does a four fold rise in titer from in-contact animals from two samples taken three to four weeks apart for lepto indicate?

Stronger evidence that lepto is the cause of abortion

How do you rule out L. pomona infection?

No titers in herd >1:3000

Cannot rule it in based on titers

How do you control lepto?

Vaccination but will only provide a short duration of immunity

Antibodies are serovar specific

Clearance form bloodstream is not same as clearance from body

Minimize standing water and limit additions to herd

Control wild animals

Where does lepto persist?

Kidney

Brain

Repro tract

How do you vaccinate against lepto?

Heifers vaccinated 2-3 times at month intervals pre breeding and annual after that

What does Brucella abortus cause in humans?

Undulant fever

how do humans get Brucella abortus?

Direct contact from genital secretions from abortions

Consumption of raw milk

Exposure to vaccine on accident

T/F Brucella abortus is reportable?

True, basically eliminated

Where is Brucella abortus still present?

Greater Yellowstone Area

What is the eradication plan for B. abortus?

Quarantine infected herds

Vaccination young animals

test and slaughter

Surveillance at slaughter

T/F all 50 states are B. abortus free?

True

how is Brucella abortus transmitted?

Cow: persists in mammary gland and supramammary transmission through milk to calf. Also uterus from genital secretions after abortion

Bulls: orchitis and epididymitis infects semen then semen to cattle

Why are bulls never vaccinated for B. abortus?

Causes orchitis, epididymitis, or seminal vesiculitis

What do you do if a cattle get B. abortus?

Vaccinate between 4-12 months old only but only accredited vets can

What is Neospora caninum?

Protozoa similar to toxo that causes abortion without other C/S usually

What are the C/S of Neospora caninum?

1. Abortion midgestation with autolyzed or mummified fetus

2. Stillbirth

3. Neurologic signs in calves <2 months of age from in utero infection

4. BN

5. No C/S but chronically infected

6. No C/S and not infected even though mom was infected

What is the endemic cause of Neospora caninum?

Sporadic abortion problems persisting in a herd due to vertical transmission

What is the epidemic cause of Neospora caninum?

An abortion storm when a herd is exposed to horizontal transmission through feed infected with dog feces

What is the benefit of seropositive cattle with N. caninum?

More resistant to abortion storms

What is the problem with seropositive cattle with N. caninum?

More persistent abortions throughout the years

What N. caninum transmission occurs with good efficiency?

Vertical transmission with the first pregnancy after infection likely going to be an abortion

What are the stages of N. caninum?

Tachyzoites and bradyzoites

What are tachyzoites?

Actively penetrate cells and divide rapidly

Can cross placenta to cause fetal infection

What are bradyzoites?

Slowly dividing, dormant stage

Encysted within tissue cysts

Only found in neural tissue

What is the life cycle of N. caninum?

1. Bradyzoites switch to tachyzoites

2. Tachyzoites move from dams tissues to enter bloodstream

3. Tachyzoites cross the placenta and infect the fetus

What can cause N. caninum bradyzoites to become a tachyzoite?

Immunosuppression (pregnancy)

What determines host and fetal response to N. caninum?

Severity of parasitemia

When pregnancy parasitemia occurs

Whether or not fetus is infected

What significantly inhibits N. caninum multiplication?

CD4+ T cells, interferon gamma, macrophages

How does N. caninum enter the herd?

From canines that are around the herd and cows eat the feces

What is the lifecycle of N. caninum?

Tissue cysts in aborted fetuses and infected placenta

Consumed by a dog (definitive host)

Passed oocytes in feces

Contaminates feedstuff and new cattle get infected

How do you diagnose N. caninum?

IHC staining of fetal tissue to detect the parasite. Brain in 10% formalin is the best tissue

The test is not very good still in seropositive cows. Need to combine with history

Negatives are very accurate

What is serology good for with N. caninum?

Negatives are good, but positive does not guarantee it caused the disease

How do you prevent and control N. caninum?

No drugs can kill tissue cysts

Vaccine is not available

Can control by culling seropositive cattle but then you increase risk of abortion storm

Can try and prevent canids from defecting near food

What is IBR?

Infectious bovine rhinotracheitis

How is IBR transmitted?

Respiratory, ocular, and repro secretions

T/F IBR causes latent infections?

True, it is a herpes virus

How can IBR manifest?

Respiratory disease

COnjunctivitis

Infectious pustular vulvovaginitis

CNS disease

Abortion 1-2 after clinical sings

What is a common sign of an IBR abortion, but not pathognomonic?

Retained fetal membranes

How do you diagnose IBR abortion?

Histo identification of small necrotic foci in the liver

Serology is not useful due to vax and ubiquity

How do you control IBR?

Heifers given MLV vaccine two or more times from weaning to 4-6 weeks before breeding

Adult cows get boosted once a year

What should not get the IBR vaccine?

Naive pregnant cows, can cause abortion

What is the most common cause of IBR abortions?

Iatrogenic with improper vaccine giving

What are the production losses from BVD?

Repro loss

Clinical disease

Immunosuppression for other diseases

Loss from PI animals

What does BVD cause?

Respiratory: part of BRD

DIgestive: diarrhea

Repro: abortion, stillbirths, and fatal birth defects

How is BVDV transmitted?

Horizontal from direct contact, inhalation, or ingestion of contaminated material

PI animals will shed throughout life

Vertical during gestation creating a PI animal

What is the only way for a PI BVDV animal to get it?

Vertical transmission

Describe PI BVDV animals

Very high viremia with shedding from everything in the body

What happens with a pregnant female gets BVDV at 1.5-4 months of gestation?

They get a PI calf and that calf will then always have a PI animal

How do you control BVDV?

Prevent creation of PI calves

What do you do if your herd if BVDV free?

Conduct screening tests on high risk animals

Have good biosecurity by vaccinations and prevent comingling

How do you identify PI animals?

Test all calves and if negative they always be negative

If positive remove calves from breeding and test dam. If positive cull. Positive cows and bulls should be sold

When do you want to identify PI BVDV animals?

Prior to breeding season

To prevent BVDV what should you do when purchasing nonpregnant females?

Heifers and cows must be PI test negative and quarantine for 30 days

What should you do to prevent BVDV when purchasing bred females?

Must test negative and quarantine until calving and calf is non-PI

How do bulls shed BVDV?

Semen, should test before breeding

T/F fomites can cause BVDV transmission

True

T/F embryo transfer can cause BVDV transmission?

True

T/F wildlife can get BVDV?

True

What is the best way to control BVDV?

Vaccination

What is the summary of controling BVDV?

Find and remove PI animals

Segregate and isolate new animals

Vaccination to prevent risk of fetal infection

What are some common iatrogenic causes of abortion?

PGF2alpha

MLV IBR

Dexamethasone

Brucellosis vaccine

Gram negative vaccine endotoxemia

Sodium iodine IV

What are some noninfectious causes of abortion?

Genetic (usually early in gestation)

Teratogens

Nutritional

Hormonal asynchrony

Exogenous corticosteroids

High temp

What are some nutritional causes of abortion?

Acute starvation

Protein deficiency (weak calf syndrome)

Vitamin A deficiency

Iodine deficiency