Control bovine respiratory syncytial virus and BCV

To generate the knowledge necessary to design a cost effective control program towards BRSV and BCoV in the Norwegian cattle population.

Secondary objective for the BCV experimental WP:

Evaluate the most important dispersal patterns of BCoV

a) the role of direct transmission (live animals)

b) the role of indirect transmission (humans, utensils) The Norwegian cattle population is free of many infectious diseases; many due to eradication programs. The two most costly infections today is BRSV, causing contagious respiratory disease, and BCoV, causing diarrhea in calves and adults (winter dysentery). BRSV is one of the most serious welfare problems and practically all outbreaks of respiratory disease are caused by BRSV in Norway. A recent outbreak of winter dysentery showed that the larger dairy herds lost NOK 100 000 each in reduced milk production. In addition both infections have detrimental effects on the cows' welfare, milk quality, growth rate, feed utilization, reproduction performance, and increases the use of antibiotics. Preliminary data shows serious and hitherto underestimated consequences on profitability and animal welfare of BRSV and BCoV. It is probably possible to limit the incidence of these infections. That requires documented knowledge on economic consequences, dispersal patterns, transmission modes between herds and preventive measures. The project's aim is to generate this knowledge and communicate the results. This is going to form the basis of an eventual control program of international significance.

The project includes a screening of all dairy herds in Norway based on antibodies against BRSV and BCoV in bulk tank milk. Negative herds will be re-tested annually to identify recently infected herds. Together with information on preventive measures implemented and the purchase of live animals the effect on these measures and trade with animals can be evaluated. The dissemination pattern will be analyzed by genetic analysis of virus strains from outbreaks. Experimental infections in calves will also be conducted to study transmission of virus via the airway mucosa of humans as well as equipment commonly brought from farm to farm by veterinarians.

Finally the different preventive measures as well as a possible control program will be assessed by cost-benefit analysis.

Financier: Norska Fondet for forskningsavgift på landbruksprodukter og Forskningsmidler over jordbruksavtalen (Matfondavtale)
Co-applicant: Maria Stokstad, Norges Veterinærhøgskole Olav Østerås, TINE SA, Stefan Alenius, KV, SLU