Exam 3 - Infectious Infertility

Question 1

what herpesvirus is the most common cause of abortion in mares? when is it most contagious? when is it shed? how is it transmitted?

Answer 1

EHV-1 (EHV-4 less common)

most contagious during 1st week of infection

sheds for 7-15 days

respiratory transmission! transplacental transmission!

Question 2

why is transplacental transmission of EHV-1 in mares bad? what does the abortion look like? what happens if the mare ends up having the foal?

Answer 2

can cause abortion in late gestation - expelled fresh with the foal enclosed in amnion & the foal may or may not be alive but they will die because of lung damage!

mare may have a weak foal with pneumonia

Question 3

how is EHV-1 diagnosed in mares?

Answer 3

samples taken from the aborted fetus!!!

virus isolation, PCR - looking for intranuclear inclusion bodies

Question 4

how is EHV-1 prevented?

Answer 4

vaccinate the momma at 3, 5, 7, & 9 months of gestation

virus is inactivated outside of the body by detergents, heat, & disinfectants but will last longer in cold or feces

Question 5

what is the agent that causes contagious equine metritis?

Answer 5

taylorella equigenitalis

Question 6

when was the last outbreak in the USA of contagious equine metritis?

Answer 6

2009 in kentucky at the specialized AI farm - fomite transmission was proven!!!

Question 7

how is equine contagious metritis transmitted?

Answer 7

venereally!!! stallion is asymptomatic & mares may not exhibit signs, which is why this disease is insidious

Question 8

T/F: contagious equine metritis is very susceptible to antibiotic therapy

Answer 8

true

Question 9

how long is the incubation period of contagious equine metritis? how long do they have clinical signs?

Answer 9

13 day incubation

2 weeks of purulent vaginal discharge

Question 10

what clinical signs are associated with contagious equine metritis?

Answer 10

vaginal discharge, endometritis, vaginitis, cervicitis, & short-term infertility

Question 11

how is contagious equine metritis diagnosed?

Answer 11

sample the clitoral fossa in mares & penis in the stallion

mare will have purulent vaginal discharge 13 days after breeding!

Question 12

how is contagious equine metritis prevented?

Answer 12

post-entry quarantine of imported mares, culture/PCR, & test bred to negative mares 12-45 days later!!

Question 13

why must you test bred to negative mares for contagious equine metritis 12-45 days later?

Answer 13

70% of positive stallions culture negative!!!

Question 14

what is the distribution of equine viral arteritis? how is it spread?

Answer 14

world wide! bad!

spread by semen or sometimes trans-placental if embryo transfer, if donor was bred with infected semen - not very resistant for an organism but it can survive well in frozen semen

Question 15

what horse breed has a high seropositive rate for equine viral arteritis?

Answer 15

standardbreds

Question 16

what is the incubation period of equine viral arteritis?

Answer 16

2-13 days

Question 17

why is equine viral arteritis bad for horses?

Answer 17

causes abortion, foal death, & decreases commercial value of stallions

Question 18

what clinical signs are seen with equine viral arteritis?

Answer 18

none to edema & skin rashes - peri-oribital edema & scrotal edema

Question 19

what clinical signs are seen in mares with equine viral arteritis?

Answer 19

short term carrier of the virus - abortion at 3-10 months & foals are infected

Question 20

what clinical signs are seen in stallions with equine viral arteritis?

Answer 20

long term carrier!!! disease is androgen dependent!!!

harbored in the ampullae - asymptomatic carrier, chronically shed in semen, & transmitted to mares during breeding

suborbital/periorbital edema & ventral/scrotal edema

Question 21

how is equine viral arteritis diagnosed in stallions? what is the treatment for it?

Answer 21

serologic evaluation & then VIRUS ISOLATION FROM SEMEN!!!!!

treatment isn’t possible :/ you would have to decrease testosterone!

Question 22

how is equine viral arteritis diagnosed in mares? what about in aborted fetuses?

Answer 22

mare - PCR & paired serum titers 3-4 weeks apart

aborted fetus - virus isolation from lungs, livers, & vascular lesions seen on histopathology

Question 23

why is the vaccine for equine viral arteritis not recommended to be given for the last 2 months of gestation in mares?

Answer 23

they will shed a small amount

Question 24

how is equine viral arteritis prevented?

Answer 24

isolate first time stallions for 3-4 weeks - booster them yearly with the vaccine

vaccinate teaser stallions

segregate pregnant mares

breed sero-positive stallions to sero-positive mares

establish serological status before vaccines!!!!!! some places will think seropositive means infected

Question 25

what agent causes equine coital exanthema?

Answer 25

EHV-3

Question 26

what lesions are seen in equine coital exanthema?

Answer 26

painful pustules/ulcers on the vulva & penis

Question 27

how is equine coital exanthema diagnosed?

Answer 27

appearance/lesions seen, PCR, & histopathology

Question 28

how is equine coital exanthema transmitted?

Answer 28

direct contact, fomites (AI, probe, sleeve)

Question 29

how long do lesions last with equine coital exanthema?

Answer 29

lesions are self-limiting & last 10-14 days

Question 30

nocardia is associated with what pathology in mares?

Answer 30

mucoid placentitis associated with gram positive actinomyces spp.

Question 31

what is the pathogenesis of nocardia in horses? what is the transmission?

Answer 31

we don't know either!! we know it isn't ascending or hematogenous unable to induce this condition - maybe associated with caterpillars

Question 32

what clinical signs are associated with nocardia in horses?

Answer 32

late term abortion, weak foal with normal delivery cranio-ventral portion of the placenta is affected

Question 33

what animals/situations is nocardia associated with?

Answer 33

hot weather, older mares, & large horse farms

Question 34

how is nocardia treated in horses?

Answer 34

empirical treatment - sensitive to SMZ & doxycycline

Question 35

what causes fescue toxicosis?

Answer 35

animal ingests grass that is infected with endophyte fungus ergot alkaloids!

Question 36

what clinical signs are associated with fescue toxicosis?

Answer 36

agalactia is the big one!!! prolonged gestation, dystocia, weak foals, & thick placentas

Question 37

why does fescue toxicosis cause agalactia?

Answer 37

ergot alkaloids cause reduced prolactin & progesterone

Question 38

why does fescue toxicosis cause placental problems?

Answer 38

causes a thickened placenta that can lead to RED BAG!!!! or foal delivered in chorioallantois

Question 39

why does fescue toxicosis affect fertility of horses?

Answer 39

causes prolonged luteal function, increased cycles/pregnancy, & embryonic death

Question 40

what happens if a mare does produce milk with fescue toxicosis? what happens to these foals that drink it?

Answer 40

if milk is present - it is brown & not nutritious foals that receive colostrum have a reduced ability of absorption, so IgG will be low regardless of receiving colostrum

Question 41

what is domperidone used for in horses with fescue toxicosis?

Answer 41

it is a D2 dopamine receptor blocker that will prevent ergot alkaloids from decreasing prolactin - stops them from mimicking dopamine which is what causes the decrease in prolactin

Question 42

what is the treatment/prevention of fescue toxicosis?

Answer 42

remove mares from affected pastures 40-90 days before foaling

Question 43

T/F: fescue toxicosis can cause prolonged gestation which can lead to dystocia especially if the mare has a large foal

Answer 43

true

Question 44

what is mare reproductive loss syndrome (MRLS)?

Answer 44

increased early fetal loss (35-100 days) with cloudy flocculent fluid

Question 45

what is seen in late gestation in horses with mare reproductive loss syndrome?

Answer 45

red bag, engorged placenta, foals are born weak & die - associated with alpha-hemolytic strep & actinobacillus

Question 46

horses grazing with _______ _____ trees with _____ ______ ________ are at risk for getting mare reproductive loss syndrome especially in warm summer months

Answer 46

black cherry trees eastern tent caterpillars

Question 47

what clinical signs are seen in horses with mare reproductive loss syndrome?

Answer 47

endophthalmitis, pericarditis, early fetal loss, & funiculitis

Question 48

what treatment is used for mare reproductive loss syndrome? what follow up care is used?

Answer 48

treatment - supportive care follow up - few mares rebred to eCG level from endometrial cups abortion activity associated with exoskeleton/cuticle embedded in the deep submucosa of gi tract

Question 49

you see this isolated from aborted foal tissues - what do you suspect?

Answer 49

EHV-1

Question 50

the agent pictured on bottom causes the clinical signs seen in the photo on top - what is it?

Answer 50

contagious equine metritis caused by taylorella equigenitalis

Question 51

where will you take samples from a stallion when testing for contagious equine metritis?

Answer 51

urethral sinus, terminal urethra, external penis, & prepuce

Question 52

this stallion has a lot of scrotal edema - what do you think is going on?

Answer 52

equine viral arteritis

Question 53

what is the initial diagnostic done when looking for equine viral arteritis in a stallion? what is done next?

Answer 53

initial - serologic evaluation next - determine carrier status by virus isolation in the semen

Question 54

you have horses presenting with these lesions on a large horse farm - what do you think is going on? what is this going to affect on this farm?

Answer 54

equine coital exanthema management consideration - going to affect copulation because it is painful!!

Question 55

the cranio-ventral portion of this placenta is affected and was taken from a late term aborted foal - what are you concerned about?

Answer 55

nocardia - focal mucoid placentitis with associated gram positive actinomycetes spp.

Question 56

what is the agent causing fescue toxicosis?

Answer 56

neotyphodium coenophialum - ergot alkaloid

Question 57

a foal was just delivered like this - what is going on?

Answer 57

foal delivered in chorioallantois - fescue toxicosis

Question 58

what is this?

Answer 58

red bag - EMERGENCY

Question 59

all of these clinical signs are associated with what condition in mares?

Answer 59

mare reproductive loss syndrome

Question 60

what are these bugs? what condition are they associated with?

Answer 60

eastern tent caterpillars - mare reproductive loss syndrome