Genital infection and transmission of pseudorabies virus in feral swine in Florida, USA

doi:10.1016/S0378-1135(96)01307-7

Veterinary Microbiology

Volume 55, Issues 1–4, April 1997, Pages 131-139

https://doi.org/10.1016/S0378-1135(96)01307-7 Get rights and content

Abstract

Seventeen feral swine (FS) naturally infected with pseudorabies virus (PRV) and treated with dexamethasone (4 mg/kg body wt) on five consecutive days shed virus primarily from the genital tract and less frequently from the upper respiratory tract. The FS isolates were identified as PRV by virus neutralization with specific polyclonal antiserum and by direct immunofluorescence. Restriction endonuclease analysis with BamHI showed that representative samples from a total of 62 isolates were identical to each other, but differed in at least 5 DNA bands from the PRV Shope reference strain profile. DNA purified from FS isolates propagated in Vero cells or DNA extracted directly from genital swabs were amplified in the polymerase chain reaction using primers specific for the gpII (gB) gene of PRV. This amplification yielded a product of the expected size (200 bp), which specifically hybridized to a digoxigenin-labelled 30-mer probe complementary to an area within the region defined by the primers. In a transmission experiment, PRV was recovered from the vagina at 1 and 6 weeks after uninfected feral gilts were mixed with infected feral boars. PRV was not isolated from the upper respiratory tract of either gilts or boars. At eight weeks, 4 of the 5 gilts had developed low titer neutralizing antibodies to PRV. Our results indicate that PRV in FS is transmitted through sexual contact.

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Citation Excerpt :
However, in the Bartha-K61-vaccinated groups, most piglets showed obvious clinical symptoms, developing a fever, locomotor ataxia, and respiratory distress. PRV is a large double-stranded DNA virus encoding more than 70 proteins, including capsid, tegument, and envelope (glycoproteins and other membrane proteins) (Pomeranz et al., 2005; Romero et al., 1997). Glycoproteins function in virus entry, egress, and cell-to-cell spread, modulate the immune response, and promote syncytia formation.
Pseudorabies virus (PRV) is a swine alpha-herpesvirus that mainly causes reproductive disorders in sows and neurological diseases in piglets. Vaccination is the most efficient method to prevent the disease. In China, since the emergence of PRV mutant strains in late 2011, the traditional commercial vaccines have not been providing complete protection. Our previous studies have demonstrated that PRV ZJ01 is a highly virulent strain, and its derivative, ZJ01R, which carries the gE/gI/TK gene deletion, could provide protection against the variant PRV challenge. However, the difference in immune efficacy between ZJ01R and other commercial vaccines remains unclear. In this study, the immune protection efficacy between ZJ01R and three commercial PRV vaccines (Bartha-K61, HB2000, and SA215) was evaluated in piglets. The safety of ZJ01R was shown to be equivalent to that of the three commercial vaccines. The titers of the neutralizing antibodies against the PRV classical strain LA in the four vaccine groups were similar, while the anti-PRV variant neutralizing antibody titers in the ZJ01R group were significantly higher than those in the Bartha-K61, HB2000, and SA215 strain groups. After the PRV challenge, ZJ01R, HB2000, and SA215 vaccinations could provide complete protection, whereas the Bartha-K61 vaccination could only provide 60 % protection. Importantly, the rectal viral excretion and PRV DNA loads in the lung tissues in the ZJ01R group were significantly lower than those in the Bartha-K61, HB2000, and SA215 groups. Altogether, these results indicated that ZJ01R could provide higher protection efficacy against the PRV virulent ZJ01 challenge than the three commercial PRV gene-deleted live vaccines derived from the classical vaccine strains, providing the potential to develop a new PRV vaccine to control the epidemic PRV variant strains in the future.
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Paper from the second symposium on eradication of Aujeszky's disease (pseudorabies) virusGenital infection and transmission of pseudorabies virus in feral swine in Florida, USA

Abstract

J. Virol. Methods

Res. Vet. Sci.

Measures for the control of Aujeszky's disease in Denmark

The pathogenesis of herpes simplex virus infections: Latency

Serologic survey of California wild hogs for antibodies against selected zoonotic disease agents

JAVMA

Survey of selected diseases in wild swine in Texas

JAVMA

Isolation of pseudorabies (Aujeszky's disease) virus from a Florida panther

J. Wildlife Dis.

Isolation of pseudorabies virus from trigeminal ganglia of a latently infected sow

Am. J. Vet. Res.

Studies of semen parameters during pseudorabies infection in the boar

Molecular Cloning. A Laboratory Manual

Paper from the second symposium on eradication of Aujeszky's disease (pseudorabies) virus
Genital infection and transmission of pseudorabies virus in feral swine in Florida, USA