Study of cattle persistently infected with bovine viral diarrhea virus that lack detectable virus in serum.
OBJECTIVE
To determine whether cattle persistently infected with bovine viral diarrhea virus (BVDV) that lack virus detectable in serum by use of the immunoperoxidase microtiter assay (IPMA) can transmit the virus to susceptible herdmates and determine prevalence of these cattle.


METHODS
Clinical trial and serologic survey.


METHODS
2 cattle and 1,952 blood samples.


METHODS
A persistently infected cow in which virus could not be detected in serum was housed with a BVDV-seronegative steer. Blood and nasal swab specimens were tested via virus isolation and serum virus neutralization. Parallel WBC preparations and sera from blood samples of 1,952 adult cows were screened for BVDV by use of IPMA.


RESULTS
The steer seroconverted to BVDV within 4 weeks of contact with the cow. Virus was detected in sera and WBC of 5 adult cows that were verified as persistently infected by retest 3 weeks later. Cattle persistently infected with BVDV in which virus could not be detected in both serum and WBC by use of IPMA were not found.


CONCLUSIONS
Cattle persistently infected with BVDV in which virus cannot be detected in serum by use of IPMA may serve as virus reservoirs for infecting susceptible cattle. Persistent infection was detected at a prevalence of 0.26%. Screening adult cattle by use of IPMA on serum samples appears to be a reliable means of detecting persistent infection with BVDV. Prevalence of cattle persistently infected with BVDV that have negative results of IPMA on serum is extremely low.
Grooms
D L
DL
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824, USA.
Kaiser
L
L
Walz
P H
PH
Baker
J C
JC
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001681:Biological Assay / Q000379:methods; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000097:blood* / Q000453:epidemiology / Q000635:transmission*; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology / Q000302:isolation & purification*; D004197:Disease Reservoirs / Q000662:veterinary; D005260:Female; D007124:Immunoenzyme Techniques / Q000662:veterinary; D008297:Male; D015995:Prevalence; D016036:Seroepidemiologic Studies
D000914:Antibodies, Viral