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The response to this title’s question may vary. In countries and poultry farms with fragile biosecurity measures, infectious coryza in chickens is an endemic disease. Now, in developed poultry farming regions, it was, for a long time, under control. However, it has been proven that there are challenges of the disease in poultry farms even with frequent vaccination.
This situation recently seen in Brazilian breeding stocks can be attributed to a few factors. One of them is the fact that the housings are larger and with greater poultry stocking density, which facilitates horizontal contamination (from the infected bird to the healthy bird). Another factor is that we may be facing variant strains of Avibacterium paragallinarum — as it happened in poultry farming areas of South Africa.
“Infectious coryza is a disease that is difficult to control when there are variant strains, because, in the development of a vaccine, only a few Avibacterium paragallinarum serovars are chosen, which may be different from those that circulate in the field”, explains Biocamp’s Business Manager, Nelson Haga.
The vaccination program itself can also be misaligned and be a factor that contributes to the appearance of new cases of infectious coryza. There may be an inadequate concentration of bacteria (antigen) or a delayed or insufficient immune response.
“Furthermore, inactivated vaccines against infectious coryza associated with other bacterial and viral agents are good alternatives considering the cost-effectiveness, but end up having lower response specificity. So, when there is an association of immunizing agents in the same product, it may lose its efficacy”, says Nelson.
Considering all this, what is the best way to currently prevent the flock against infectious coryza?
Management and vaccination
Good management practices associated with a strict vaccination protocol are essential to prevent and contain infectious coryza. As the bacterium Avibacterium paragallinarum hardly survives outside the host, efficient management measures already contribute to its control — check here the 7 biosecurity measures for commercial laying hen farms.
However, the best prevention tool is the immunization of chickens. And an effective vaccination program is one in which vaccines are chosen according to current field challenges. The first recommendation is to protect the flock against mycoplasmosis, an opportunistic disease that can worsen the symptoms of infectious coryza. We talk more about the subject here.
The second recommendation is to protect the flock directly against infectious coryza. Currently, there are vaccines on the market that have Avibacterium paragallinarum serotypes A, B and C and guarantee broad protection against field challenges. However, faced with a possible scenario of variant strains, the autogenous vaccine ends up being one of the main alternatives for control – and needs to be considered.
Autogenous vaccines: effective measure against variant strains
Autogenous vaccines are indicated when commercial line vaccines do not provide adequate protection to the birds. They enter to control the outbreak of a disease already present in the flocks or to guarantee the immunity of the flocks that are housed on the same property.
Also known as autologous vaccines or autovaccines, they are customized products produced to meet the specific needs of disease prevention on the property, as they are prepared with the same agent that is causing the infectious disease.
Nelson recommends two doses of autogenous vaccine against infectious coryza, the first between 5 to 6 weeks and the second between 12 to 14 weeks of old, and reinforces that this type of measure has already been effectively applied in some flocks where there is a infectious coryza challenge.
If you understand that winter is a critical period for laying hens and you want to prevent your farm against respiratory problems and production losses, see how to adjust your vaccination program so that infectious coryza does not enter your farm. Talk to one of Biocamp’s technicians!
Now, if you are currently facing this challenge on your farm, learn about AutoVac®! The vaccine developed by Biocamp and approved by MAPA (Ministry of Agriculture, Livestock and Food Supply) undergoes strict quality control to reduce production losses.