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Bovine herpes virus 1 / infectious bovine rhinotracheitis (IBR) - Coggle…
Bovine herpes virus 1 / infectious bovine rhinotracheitis (IBR)
what is IBR
viral respiratory disease caused by
bovine herpes virus 1 (BHV-1)
can also cause a mild venereal infection in adult cattle or brain infection in calves
can lead to 1ry or 2ry pneumonia
clinical signs
nasal discharge
thick + purulent, also red crusty nose
fever
pyrexia 40-42C
conjuctivitis
IBR virus enhances the pathogenicity of Moraxella bovid (pink eye) and severe infectious keratoconjunctivitis lesions can develop in calves
acute disease in dairy cattle usually accompanied by severe and prolonged drop in milk production
abortion / reduced fertility
highly susceptible to 2ry bacterial infections
coughing (inflammation and damage to upper airways)
halitosis due to ulcers in mouth
signs if acute IPV (Infectious pustular vulvovaginitis) or IPB (Infectious pustular balanoposthitis) infection occurs in a naïve herd
oedema of genital mucosa, small pustules and ulcers
vaginal and preputial discharge
pyrexia
pain and discomfort
infertility of females due to pain and delayed healing of ulcers after natural infection
transmission
shed in
respiratory secretions
shed in
semen
of infected bulls
animal mounts immune response, but virus remains as latent infection. If subjected to stress the virus is shed. Usually there are no clinical signs of the disease.
shed in
vaginal discharge
aerosol and direct contact --> IBR
venereal transmission --> IPV IPB
vertical transmission can occur with BHV-1 infections
Risk factors
open herds --> buying in animals
using shared/hired bulls
nose to nose contact with neighbours
differential diagnoses in individual cattle
pneumonia
malignant catarrhal fever
mucosal disease
differential diagnosis in a group of cattle
bluetongue
foot and mouth disease
other causes of respiratory disease in cattle (bovine parainfluenza virus, bovine respiratory syncytial virus, bovine coronavirus, bacterial pneumonia, lungworm)
Diagnosis
serology for latent infections or direct detection of the virus (PCR or fluorescent antibody tests on ocular or nasal secretions) for active infections
Measuring bulk milk antibody titres can be a very useful means of determining IBR status of the herd. However, a negative bulk milk result does not necessarily indicate that a herd is IBR-free as up to 20% of the milking herd can be latently infected with IBR before the bulk milk result will become positive, therefore blood testing is essential to confirm IBR-free status of a herd.
dairy: take a bulk milk sample and perform ELISA antibody tests
beef: take individual blood samples and perform ELISA antibody tests
treatment
There is no specific treatment for IBR, secondary bacterial infections can be managed with antibiotics and animals with a high fever treated with non steroidal anti-inflammatories. Preventative vaccination of the remaining herd members may aid in minimising disease spread.
endemic herd infection to reduce shedding ==> inactive vaccine
whole herd therapeutics in an acute outbreak (protection) --> live vaccine
VACCINATION + BIOSECURITY
if herd uninfected
Closed herd (may not be practical)
Quarantine all incoming animals, if not closed, for 4 weeks with appropriate testing regime
Avoid nose to nose contact with neighbours use double fencing 3 m apart
Regular monitoring
Vaccination if none of the above are possible with a DIVA (marker) vaccine