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== Introduction<br> ==

== Introduction ==

Bovine Respiratory Syncitial Virus (BRSV) is a respiratory condition in cattle that is more serious than [[Bovine Parainfluenza - 3|PI-3]]. It replicates in nasal epithelium and then dispreses throughout the upper respiratory tract to the bronchial tree. Here, syncytia form and further spread into the bronchioles occurs. <br>

Bovine Respiratory Syncitial Virus ('''BRSV''') is a respiratory condition in cattle that is more serious than [[Bovine Parainfluenza - 3|PI-3]]. It replicates in nasal epithelium and then disperses throughout the upper respiratory tract to the bronchial tree. Here, syncytia form and further spread into the bronchioles occurs.  

Outbreaks of RSV associated disease usually occur associated with winter housing and also during periods of stress such as mixing of calves and transport. The virus can contribute to calf enzootic pneumonia.<br>

Outbreaks of RSV associated disease usually occur associated with winter housing and also during periods of stress such as mixing of calves and transport. The virus can contribute to [[Enzootic Pneumonia - Calves|calf enzootic pneumonia]].

Subclinical reinfections are important in spreading disease and more than 70% of cattle in the UK have antibodies to BRSV.<br><br>

Subclinical reinfections are important in spreading disease and more than 70% of cattle in the UK have antibodies to BRSV.

== Signalment<br> ==

== Signalment ==

This virus can occur as part of the calf pneumonia syndrome along with Parainflunza and Herpesvirus (IBR) as well as the bacteria Mannheimia, Mycoplasmas and Pasturella.<br>

This virus can occur as part of the [[Enzootic Pneumonia - Calves|calf pneumonia syndrome]] along with [[Bovine Parainfluenza - 3|Parainflunza]] and [[Infectious Bovine Rhinotracheitis|Herpesvirus (IBR)]] as well as the bacteria [[Mannheimia haemolytica|''Mannheimia'']], [[:Category:Mycoplasmas|''Mycoplasmas'']] and [[Pasteurella multocida|''Pasturella'']].

It can cause disease in adult cattle too however, it is more severe in young stock.<br>

It can cause disease in adult cattle too however, it is more severe in young stock.

== Clinical Signs<br> ==

== Clinical Signs ==

Clinical signs include [[Pulmonary Emphysema|emphysema]] and [[Pulmonary Oedema|oedema]]. In adult cattle, you may see a drop in milk yield. <br>

Clinical signs include [[Pulmonary Emphysema|emphysema]] and [[Pulmonary Oedema|oedema]]. In adult cattle, you may see a drop in milk yield.  

== Diagnosis ==

== Diagnosis ==

Often when in combination with other viral agents and bacteria then diagnosis is presumptive due to number of animal affected and the age and circumstances of these (housed etc). A dose of anitbiotics is usually given and an effect is often seen quickly.<br>

Often when in combination with other viral agents and bacteria then diagnosis is presumptive due to number of animal affected and the age and circumstances of these (housed etc). A dose of [[antibiotics]] is usually given and an effect is often seen quickly.

If the animal has succumbed to the disease a post mortem can be performed to aid diagnosis. Diseased lung tissue from dead animals or centrifuged cells from lung lavage can be used for this. The virus is too fragile for cell culture isolation (often inactivated in transport). <br>

If the animal has succumbed to the disease a post mortem can be performed to aid diagnosis. Diseased lung tissue from dead animals or centrifuged cells from lung lavage can be used for this. The virus is too fragile for cell culture isolation (often inactivated in transport).  

Grossly on post mortem, one will see cranioventral atelectasis and consolidation, interstitial emphysema, which is more prominent in the caudal lung lobes. The results from bronchoconstriction which results in airway obstruction - this constriction is thought to arise from mast cell degranulation and histamine release. Histologically, one may see acute bronchiolitis, characteristic of the bronchiolar response is the formation of syncytial giant cells (formed by proliferating bronchiolar epithelial cells which may contain intracytoplasmic inclusion bodies) and the alveolar epithelium sometimes affected. The broncioles are often obstructed by exudate and these may later become obliterated by the fibrous tissue of organisation.<br>

Grossly on post mortem, one will see cranioventral [[atelectasis]] and consolidation, interstitial emphysema, which is more prominent in the caudal lung lobes. The results from bronchoconstriction which results in airway obstruction - this constriction is thought to arise from mast cell degranulation and histamine release.  

Antigen detection by '''immunocytochemistry''' for intracytoplasmic viral inclusions containing labelled viral protein can also be performed as well as serology. A 4-fold rise in ELISA antibody in paired serum samples from several animals is indicative of the disease.<br>

Histologically, one may see acute [[bronchiolitis]], characteristic of the bronchiolar response is the formation of syncytial giant cells (formed by proliferating bronchiolar epithelial cells which may contain intracytoplasmic inclusion bodies). The alveolar epithelium is sometimes affected. The bronchioles are often obstructed by exudate and these may later become obliterated by the fibrous tissue of organisation.

Treatment with anibiotics is often used to treat secondary infections and lessen clinical signs and help the body focus on eliminating the virus. <br>

== Treatment and Control ==

It is important to try and improve husbandry as in [[Bovine Parainfluenza - 3 (PI-3)#Secondary_Concerns|PI-3]] in order to prevent the disease from occuring. Avoiding mixing of different aged calves is very important in the control of the disease, as is good hygiene.<br>

Treatment with antibiotics is often used to treat secondary infections and lessen clinical signs and help the body focus on eliminating the virus.  

Vaccines are available but not effective as need to stimulate [[Lymphocytes#Cytotoxic_CD8.2B|cytotoxic T-cells]].<br>

It is important to try to improve husbandry as in [[Bovine Parainfluenza - 3 (PI-3)#Secondary_Concerns|PI-3]] in order to prevent the disease from occurring. Avoiding mixing of different aged calves is very important in the control of the disease, as is good hygiene.