Efficacy of an inactivated vaccine for prevention of reproductive failure induced by porcine reproductive and respiratory syndrome virus

• Published in: Veterinary microbiology 1997-04, Vol.55 (1), p.361-370
• Main Authors: Plana-Durán, J., Bastons, M., Urniza, A., Vayreda, M., Vilà, X., Mañé, H.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Viral - blood; Antibody Formation; Arterivirus; Biological and medical sciences; Enzyme-Linked Immunosorbent Assay; Female; Fetal Death - veterinary; Fundamental and applied biological sciences. Psychology; Immuno-peroxidase monolayer assay; Litter Size; Macrophages, Alveolar - virology; Microbiology; Porcine alveolar macrophages; Porcine Reproductive and Respiratory Syndrome - immunology; Porcine Reproductive and Respiratory Syndrome - prevention & control; Porcine reproductive and respiratory syndrome virus; Porcine respiratory and reproductive syndrome virus - growth & development; Porcine respiratory and reproductive syndrome virus - immunology; Porcine respiratory and reproductive syndrome virus - isolation & purification; Pregnancy; Reproductive failure; Swine; Vaccine; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Vaccines, Inactivated; Viral Vaccines; Virology
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/S0378-1135(96)01317-X

This report describes the results of experiments with an inactivated oily vaccine containing per dose about 10 5.5 median tissue culture infectious dose (TCID 50) of the Spanish strain of porcine reproductive and respiratory syndrome (PRRS) virus grown in porcine alveolar macrophages (PAMs). In order to evaluate the efficacy of the vaccine, two experimental infection routes were tested in sows: subsequent intranasal (I.N.) and intravenous (I.V.) (out of a total of 93 piglets born to 7 sows, 16% were mummified, 18.2% were weak and died within 48 h of birth, 37% were stillborn, 5.3% died between 2 and 7 days of age, 22.5% lived for more than one week) and intranasal alone (out of a total of 65 piglets born to 5 sows, 0% were mummified, 22.5% were weak and died within 48 h of birth, 40% were stillborn, 4.6% lived for more than one week). I.N. alone was selected to evaluate the efficacy of the vaccine because this is the natural route of infection. A number of experiments were conducted to test the immunogenicity of the vaccine. In general, after challenge with the homologous strain, protection in vaccinated sows was high (at least 70% of the piglets were born alive and healthy), whereas protection in unvaccinated sows was low (only 10% of the piglets were born alive and healthy). Vaccinated animals devoid of antibodies by immunoperoxidase monolayer assay (IPMA) at the time of challenge were still protected at experimental infection.