Ex 3 - Developmental pathology and teratology Flashcards
What are 2 important principles regarding agents and the diseases they cause?
- a single agent can induce dramatically different dz at different stages of gestation
- Totally different agents can induce the same pathologic changes and phenotypes
How does veratrum californium (skunk cabbage) affect sheep at different stages of gestation?
- day 14 –> cyclopia
- 28-31 –> short legged lambs, “chrondrodysplastic phenotype”
- 30-36 –> tracheal hypoplasia
What 4 factors are involved in pathogenesis of congenital disease?
- genotype of animal (mother and conceptus)
- dose and frequency (thresholds)
- Nature of agent or insult
- stage of development
What are the three critical stages of development?
- early embryo –> can result in early fetal death
- organogenesis –> serious congenital defects
- histogenesis –> functional defects, not as severe as insults during organogenesis
What class of virus is Blue Tongue? how is it transmitted?
Orbivirus transmitted by Culicoides gnats
*Blue tongue is restricted to areas with the vector
BTV in sheep
severe disease, large outbreaks
BTV in cattle
usually subclinical
Main teratogenic effect of BTV
hydranencephaly (“bubble brain”)
What kinds of vaccines can cross the placenta?
live attenuated vaccines
Schellenberg virus
Causes: hydranencephaly, arthogryposis, kyphosis, scoliosis
Akabane virus
Transmitted by mosquitoes and Culicoides
Infected adult cattle, sheep, goats –> subclinical infection
Akabane virus lesions
abortion, stillbirth, premature birth
arthrogryposis and hydranencephaly
What is better for testing fetuses, Ag or Ab tests?
Ab!
Many Ag tests will be negative on fetal tissues –> the virus is gone before parturition, but the damage is done
Pestiviruses (name 3)
Swine fever, BVD (CP and NCP), border dz
Lesions of pestiviruses
Hydranencephaly, cerebellar hypoplasia, congenital cataracts, hypotrichosis
