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Bovine Viral Diarrhea: Mucosal Diseases: Multisystemic Diseases of…
Bovine Viral Diarrhea: Mucosal Diseases: Multisystemic Diseases of Ruminant
species
:cow:
seroprevalence in North America 40-90%
PIs <1%
can be endemic in herds
natural host
:camel:
prevalence 7-25%
PI cria
little known
:deer:
:sheep: :goat:
:water_buffalo:
clinical syndromes
naive infection
pathophysiology
replication occurs in respiratory tract
spread to epithelial tissue
GI epithelium
skin
repro tract
epithelial erosions
infection of local LNs
dissemination throughout lymph system
depletion of B and T lymphs
immunosuppression
subclinical
70-90% of cases
no obvs dz
immunosuppression
increased susceptibility to dz of any organ system
infertility
males and females
acute BVD
6-24mo of age
usually not fatal
GI tract infection
erosive gastroenteritis
clinical signs
:eye:
anorexia
depression
diarrhea
decreased milk production
:female-doctor:
fever
:hand:
oral lesions
skin and coronary band lesions
hemorrhagic syndrome
severe thrombocytopenia
plt # <25,000
plt dysfunction
mortality 25%
survivors may be unthrifty
clinical signs
:eye:
epitaxis
bloody diarrhea
:hand:
petechia
eccymoses
spontaneous/prolonged bleeding
respiratory disease
virus suppresses defenses
secondary bacterial pneumonia (BRDC)
PI calf in beef feedlot increases treatment for pneumonia in exposed animals
transplacental infection
<50d gestation
conception failure
embryonic death
50-125 d gestation
abortion
fetal mummification
development of a PI animals
rare after 100d
infection while immune system is developing
fetus sees virus as "self"
will not develop Abs to BVDV
125-150d gestation
final stages of organogenesis
congenital abnormalities
cerebellar hypoplasia
cataracts and retinal lesions
hydrocephalus
brachygnathism
misalignment of upper and lower teeth
arthrogryposis/dwarfism
150-270d gestation
fetus mounts immune response to virus
calf is seropositive
organ damage
weak, unthrifty calves
infertility
stillbirth
abortion
persistently infected (PI) animals
mucosal diseae
acute
superinfection with cytopathic (CP) strain
b/w 6mo-1yo
100% fatality
clinical signs
:eye:
depression
anorexia
profuse watery diarrhea
:hand:
fever
dehydration
acute mucosal disease
+/- oral lesions
coalescing erosions
muzzle, lips, gums, dental pad, palate, tongue
+/- skin lesions
interdigital space
coronary band
:microscope:
neutropenia
electrolyte abnormalities
chronic
superinfection with cytopathic strain
100% fatality <18mo after signs
less severe, chronic version of acute signs
infected
in utero
constant source of infection for naive animals
appearance
maybe normal
maybe small and unthrifty
outcome
most die w/n 1y
sometimes live to reproductive age
all offspring will be PI
transmission
worldwide distribution
horizontal
literally
every body fluid
vertical transmission
in utero
fomites
PI animals
animals infected
in utero
are infected for life
major source of viral shedding
100% offspring infected