The present invention relates to modified, live Porcine Reproductive and Respiratory Syndrome viruses. Viruses were genetically analyzed and selected based on phylogenetic grouping for modification by repeated passage in tissue culture. The modified, live viruses were assessed for the ability to provide protective immunity to heterologous viruses. The modified, live viruses are useful in vaccines, particularly in vaccines which can treat infection of swine by multiple heterologous viruses.

The present invention relates to porcine reproductive and respiratory syndrome virus (PRRSV) vaccines in a field of veterinary biological products, and more particularly to a PRRSV SX-105 strain having a deposit number of CGMCC No. 9906, and a use thereof in preparing PRRSV live vaccines. PRRSV SX-1 original strains are strongly pathogenic to swine. A PRRSV SX-105 attenuated strain shows safety and good immunogenicity on the swine. The PRRSV live vaccines, prepared from the PRRSV SX-105 strain, are safe and reliable, and able to generate strong immunity after immunization. The PRRSV live vaccines significantly decrease morbidity and mortality in inoculated swine groups, and have immunization effects reaching and slightly better than conventional commercial vaccines on the market, showing advantages to compete with the same kind of products around the world. The PRRSV live vaccines are capable of effectively preventing PRRS epidemic and transmission, and has broad application prospects.

The present invention relates to modified, live Porcine Reproductive and Respiratory Syndrome viruses. Viruses were genetically analyzed and selected based on phylogenetic grouping for modification by repeated passage in tissue culture. The modified, live viruses were assessed for the ability to provide protective immunity to heterologous viruses. The modified, live viruses are useful in vaccines, particularly in vaccines which can treat infection of swine by multiple heterologous viruses.

Multiple DIVA vaccines effective against porcine reproductive and respiratory syndrome virus (PRRSV) are disclosed. The DIVA vaccines may be negative DIVAs or positive DIVAs. The DIVA vaccines may be produced by modifying the nsp2 region of a modified live virus vaccine. The modification may be one or more deletions only (negative DIVAs) or a deletion with an insertion (positive DIVAs). The insertion may be of an epitope tag, such as a V5, S-Tag, or FLAG tag. Produced DIVA vaccines may be stable through multiple passes and thus may be effective for production and vaccination of animals.

A non-naturally occurring porcine reproductive and respiratory syndrome virus (PRRSV) is provided herein, and methods of making and using the non-naturally occurring PRRSV also are provided.

Disclosed herein are methods and compositions for treating or preventing Porcine reproductive and respiratory syndrome (PRRS) infection in a subject.

The present invention belongs to the field of animal health and provides means to study Porcine Reproductive and Respiratory Syndrome (PRRS), a viral disease affecting swine, and for the development of vaccines, therapeutics and diagnostics for the prophylaxis, treatment and diagnosis of PRRS. In a first consideration, the invention relates to a new PRRS virus variant, and, in a second consideration, to a nucleic acid sequence which comprises the genome of an infectious genotype I (EU) PRRS virus clone. Based on this, new PRRS vaccine candidates with improved properties are provided.

The present invention describes an efficient commercial scale production method for the preparation of PRRS virus.

A method for monitoring the viability of a megavirus in animal feed or an animal feed ingredient generally includes inoculating the animal feed or animal feed ingredient with a surrogate virus as a proxy for the megavirus, subjecting the animal feed or animal feed ingredient to a treatment that inactivates the megavirus and the surrogate virus, subjecting the animal feed or animal feed ingredient to storage or transportation conditions for at least 14 days, and determining the viability of the surrogate virus in the animal feed or animal feed ingredient, thereby monitoring the viability of the megavirus in the animal feed or animal feed ingredient. In one or more embodiments, the megavirus is African swine fever virus (ASFV) and the surrogate virus is an ASFV surrogate virus. In some of these embodiments, the ASFV surrogate virus is a Coccolithovirus such as, for example, Emiliania huxleyi virus.

Disclosed herein are methods and compositions for treating or preventing Porcine reproductive and respiratory syndrome (PRRS) infection in a subject.