Vaccines against the PRRS virus – Articles

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Most vaccines are live attenuated vaccines, but there are also commercial versions in which the virus is inactivated.

Live attenuated vaccines against genotype 1 PRRSV are authorized in all countries, although some countries allow only attenuated genotype 2 vaccines. Other countries do not allow the use of attenuated genotype 2 vaccine but allow the use of inactivated vaccine. Even in some countries there is an inactivated vaccine with both genotypes in one package.

Target species

Inactivated vaccines are registered only for sows and future producers. Attenuated vaccines have many records. There are vaccines with general registration for pigs that can be used both for breeding animals and for piglets and pigs. Others register only piglets, fattening pigs or only breeding sows.

Indications for use

Indications for use will depend on whether the vaccine is a live attenuated or inactivated vaccine, and whether it is intended for piglets, breeders, or both.

In general, whether intended for breeding stock or piglets, the indications for use of an attenuated vaccine relate to the reduction of viremia.

In particular, when it comes to reproductive females, they indicate signs like: “to reduce reproductive disorders, frequency and duration of viremia, transplacental transmission of the virus, viral load in tissues and clinical manifestations in offspring associated with infection with PRRSV strains“

When it comes to piglets or finishing pigs, specific instructions include descriptions such as: “For fattening pigs, the most important effect of the virus is on the respiratory system. In field trials, vaccinated pigs, especially piglets vaccinated at 6 weeks of age, showed significant improvements in production results (reduced incidence of PRRSV and improved daily growth and feed conversion until the end of the baiting period).or “p”to reduce viremia and nasal discharge caused by infection with European strains of the PRRS virus (genotype 1).»

It should be noted that when vaccinating piglets, the vaccination age indications in the technical passport are not the same for all vaccines, since for commercial vaccines its use is registered from the first day of life, and for others – from the first day of life. .17 days or 4 weeks.

Indications for the use of inactivated vaccines are limited to their use in breeding stock.reduction of reproductive disorders caused by the PRRS virus (European strain) in a contaminated environment. Vaccination reduces the number of premature births and the number of stillborn piglets.»

Onset and duration of immunity

In the case of attenuated vaccines, the development of immunity in piglets or fattening pigs varies from 2, 3 to 4 weeks, and the duration of immunity ranges from 24 to 26 weeks.

In sows, the development of immunity is 28-30 days, and the duration of registered immunity is 16-17 weeks.

For inactivated vaccines, the establishment and duration of immunity are not indicated.

Route of administration

PRRSV vaccines must be administered intramuscularly, but some commercial versions have the option of intradermal administration, and even one vaccine is registered for intranasal administration.

Dosage

In the case of attenuated vaccines, vaccination of piglets is carried out once from the age indicated in the indications for use, and for breeding producers – before the introduction of pigs into the farm, at each gestation or every 3-4 months. .

In the case of inactivated vaccines, vaccination and revaccination are necessary if this is the primary vaccination, and then every 3 or 4 months or at 60-70 days of pregnancy, depending on the vaccine.

Combination vaccines

There is no joint use with other microbial preparations, but there is the possibility of joint use with other vaccines.

In piglets, simultaneous use after mixing with the vaccine against Mycoplasma hyopneumonia and PCV2 or with simultaneous vaccination, but at different points of application, compared with Mycoplasma hyopneumoniaPCV2 or a mixture of PCV2 and Lawsonia intracellularis.

Livestock farmers have registered its use in a mixture with a vaccine to combat porcine parvovirus, as well as porcine parvovirus and red disease.

Contraindications, special precautions

A vaccine containing a live attenuated virus that can be excreted by animals after vaccination and has recombinant abilityIt is very important to pay attention to the various warnings or precautions in the technical data sheets, which, in brief, include warnings regarding its use to boars who produce semen for negative farms, to take precautions to avoid the spread of the vaccine virus from those vaccinated. Unvaccinated animals should be protected against PRRS and should no longer be simultaneously vaccinated with different attenuated vaccines on the same farm or allow a transition period when changing attenuated vaccines.