Videotutorial on Controlling PRRSV: Key points for PRRSV control

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Videotutorial on Controlling PRRSV: Key points for PRRSV control

More than 25 years after its appearance, PRRS continues to be the most challenging and costly disease affecting pig production. Four key points have been established in order to understand the behaviour of PRRSV and what the most suitable decisions for controlling it are.

 

The disease, of unknown aetiology, was described for the first time in the USA in the late 80s and shortly afterwards also in Europe. It was not until 1991 that the PRRSV was isolated for the first time in Lelystad. The PRRSV then spread quickly, and today it is present in the majority of pig-producing countries in the Americas, Europe and Asia. Only Australia, New Zealand, Scandinavian countries and some South American countries are free from PRRS.

HIPRA is a pharmaceutical company and a reference in prevention for Animal Health. It has its owndiagnostics laboratory and its own line of ELISA kits. A large team of professionals with broad work experience supply all of the knowledge and experience which, together with the tools available, enable us to provide the best service to clients for the control of PRRSV. Despite now having effective vaccines against the disease, HIPRA continues to invest resources in research and development in order to find a solution that is 100% effective against PRRSV. Consequently, HIPRA has the vaccine, the diagnostics, the knowledge and the experience to provide the best advice to our clients.

Part of the complexity of combating the disease at the present time is due to the wide variability that the PRRSv presents at a genetic level. This variability between strains means that cross-immunity is hardly ever complete, and in most cases is only partial. Therefore, when tackling the problem, it is firstly necessary to bear in mind where the infection comes from, in other words, if it is a homologous or heterologous infection. An endemic strain that circulates within the farm is considered to be a homologous strain, which is already present when the analytical process is started. We refer to a heterologous strain when the infective virus is not one that has previously been found in the farm, and is therefore a different genetic strain. This can have implications and repercussions on a practical level since it is unknown whether the immunity generated by the HOMOLOGOUS strain will be sufficient to control this new challenge. We therefore need to establish a series of control mechanisms to guarantee the stability of the affected farms.

The success of disease control depends on a combination of the following strategies: monitoring, which allows us not only to diagnose the disease but also to be informed about the status of the animals at all times, at what age they are infected and how the virus is transmitted within the farm. Biosecurity consists of containment measures which prevent the entrance of a new heterologous strain with regard to external biosecurity, as well as all internal biosecurity measures that enable us to minimise the circulation of the homologous strain within the farm itself. With regard to the handling of animals it is necessary to be familiar with the production system in order to identify the facilities and challenges that this represents for controlling the disease. Protocols for acclimatization and introduction of replacement animals are one of the most important points in PRRS control. This is one of the most frequent entry points of new PRRSV strains and one of the main causes of farm destabilization. Finally, active immunisation of the animals is vital in order to minimise the clinical presentation of the disease, as it enables us to reduce viral excretion and decrease infection pressure and circulation of the virus on farms.

It is therefore very important to have a complete, global view of the situation with regard to PRRS disease on our farms. Only then will we be able to apply the right measures and successfully control the disease.