Eradication of pseudorabies virus from three large swine herds achieved by management intervention and use of a vaccine with a deletion for glycoprotein I.
Three large farrow-to-finish swine herds in Illinois, quarantined because of infection with pseudorabies virus (PRV), were enrolled in an intensified PRV eradication program, with the goal being release from quarantine within 3 years. The intervention plan primarily relied on vaccination, using a vaccine with a deletion of the genes coding for glycoprotein I, in breeding and growing/finishing pigs and decreases of movement and mixing of growing/finishing pigs. The initial goal was to decrease viral spread in the growing/finishing pigs, thereby enabling production of seronegative replacement gilts. Off-site rearing of replacement gilts was implemented in 1 recently infected herd in which the seroprevalence in the growing/finishing group was high. Results of bimonthly serologic monitoring indicated that there was minimal spread of PRV in the growing/finishing pigs after 1 year. Increases in the number of sows culled combined with an increase in the number of seronegative replacement gilts entering the breeding group resulted in a reduction of sow seroprevalence, so that phased test and removal of seropositive breeding stock could commence in all 3 herds at about 18 months after initiation of the program. Persistent use of the test-and-removal procedure and repeated testing for release from quarantine were required for the most recently infected herd. All herds were released from quarantine within 3 years, indicating that a PRV eradication program based on vaccination and management changes designed to minimize the spread of PRV can be used in conjunction with test-and-removal procedures to effectively eliminate PRV from large farrow-to-finish swine herds.
Lehman
J R
JR
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61801.
Weigel
R M
RM
Hall
W F
WF
Taft
A C
AC
D000034:Abortion, Veterinary / Q000453:epidemiology / Q000517:prevention & control; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks / Q000662:veterinary; D005260:Female; D017353:Gene Deletion; D011558:Herpesvirus 1, Suid / Q000235:genetics / Q000276:immunology*; D008137:Longitudinal Studies; D008297:Male; D011247:Pregnancy; D015995:Prevalence; D011557:Pseudorabies / Q000453:epidemiology / Q000517:prevention & control*; D011790:Quarantine / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000517:prevention & control*; D014611:Vaccination / Q000662:veterinary; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins / Q000235:genetics*; D014765:Viral Vaccines / Q000235:genetics
D000914:Antibodies, Viral; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C042966:pseudorabies virus glycoproteins