Inf. diseases II - Ruminant respiratory disease 1/2 Flashcards
BOVINE RESPIRATORY DISEASE complex
is most common in what age group?
more commonly in young animals during period between passive and active immunity
Alt. Terminology in use for bovine respiratoy disease (BRD) complex (4)
Enzootic pneumonia
“Shipping fever”
Pneumonic pasteurellosis – Pasteurella spp and Mannheimia spp
Atypical interstitial pneumonia – Dictyocaulus viviparus
Clinically BRD appears
BRD = bovine respiratory disease (complex)
as pneumoenteritis
Many pathogens affect resporatory tract and intestinal tract at the same time.
Bacterial spp. that contribute to BRD (4)
BRD = bovine respiratory disease (complex)
Mannheimia haemolytica,
Pasteurella multocida,
Histophilus somni,
Arcanobacterium pyogenes
Viruses that contribute to BRD (6)
BRD = bovine respiratory disease (complex)
Bovine Respiratory Syncytial Virus (BRSV),
Bovine Herpesvirus-1
Bovine Viral Diarrhea Virus (BVDV)
ParaInfluenza 3 (PI3)
Bovine Coronavirus
Bovine Adenovirus
BRSV
Bovine respiratory syncytial virus
Bovine respiratory syncytial virus (BRSV) is an infectious disease of cattle, caused by Paramyxovirus, and characterized by (3)
fever, infection of upper respiratory tract and bronchopneumonia
BRSV causative agent
genus
family
type (RNA/DNA)
Bovine respiratory syncytial virus (BRSV)
Genus Pneumovirus,
family Paramyxoviridae
RNA virus
serotypes of BRSV?
subtypes?
2 serotypes
3 antigenic subtypes: A, AB and B
BRSV was named for its characteristic..?
cytopathic effect – the formation of syncytial cells
What is a syncytial cell?
A large cell-like, multinucleated structure formed by the joining together of two or more cells.
Host range of BRSV
cattle
Human RSV is pathogenic to calves, but BRSV is not zoonotic!
BRSV More severe clinical disease can be seen in
1-3 month-olds
Maternal antibodies do not prevent clinical disease.
Mortality in this age group is 5-20%.
Morbidity of BRSV in herd
Morbidity 80-100%
Spreads quickly within the herd.
On primary introduction to herd: severe pneumonia in all age groups.
When is BRSV most common?
Seasonality – more common during fall and winter.
Reinfections during summer months.
BRSV found where in the world?
Has been isolated in most European countries, North-America, Australia, Japan and Africa.
Basically everywhere except South America, Middle East and Asia minus Japan.
Transmission of BRSV.
Excretion: nasal discharge
Aerogenic mode of transmission
(Fomites – including human)
Route: respiratory
IP: of BRSV
IP: 3-5 days
Clinical signs of BRSV
Fever (40–42°C), depression, decreased feed intake,
increased respiratory rate, cough, and nasal and lacrimal discharge – common signs.
More severe cases:
Dyspnea in the later stages of the disease
Subcutaneous emphysema may occur
Secondary bacterial pneumonia is a frequent occurrence!
Recovery in 1-2 weeks
Post mortem signs of BRSV
Diffuse interstitial pneumonia with subpleural and interstitial emphysema along with interstitial edema
so BOTH emphysema and edema!
Bronchopneumonia
Material for diagnosis of BRSV. (2)
Nasal swabs
Lungs, trachea, bronchial LNs
Lab analyses for diagnosis of BRSV. (2)
Virus identification – PCR
Antibodies – serology (ELISA)
Tx of BRSV.
no specific Tx!
Mainly supportive care – IV fluids and electrolytes for dehydration.
In severe cases also NSAIDs can be used
ABs if secondary infections
BRSV Secondary bacterial infections are common, name 3 spp. of bact.
M. hemolytica
P. multocida
H. somni (Histophilus)