Use of real-time polymerase chain reaction to detect bovine herpesvirus 1 in frozen cattle and buffalo semen in India.

Bovine herpesvirus 1 (BoHV-1) infection in cattle and buffalo makes these animals life-long carriers of the virus which is intermittently excreted in semen. In the present study, a real-time polymerase chain reaction (PCR) was validated to screen frozen semen from cattle and buffalo for BoHV-1 by amplification of the gB gene of the virus. Analysing the intra- and inter-test variability, the assay was found to be highly reproducible. High sensitivity (100%) and specificity (90.04%) of this real-time PCR assay was recorded in comparison to virus isolation. Extended frozen semen samples from 574 cattle and buffalo bulls that were seropositive to infectious bovine rhinotracheitis (IBR) tested by real-time PCR indicated that 1.97% semen batches from cattle and 3.36% batches of buffalo semen were positive for BoHV-1. The real-time PCR protocol will be useful for screening large numbers of semen samples from IBR-seropositive cattle and buffalo bulls as the test is less time consuming and several batches of semen can be tested with ease compared to virus isolation in cell culture.

Contraceptive vaccines based on the zona pellucida glycoproteins for dogs and other wildlife population management.

Zona pellucida (ZP) glycoproteins, by virtue of their critical role in fertilization, have been proposed as candidate antigens for the development of contraceptive vaccines. In this review, the potential of a ZP-based contraceptive vaccine for the management of wildlife population, with special reference to street dogs, is discussed. Immunization of various animal species, including female dogs, with native porcine ZP led to inhibition of fertility, which was associated with the ovarian dysfunction. Immunization of female dogs with Escherichia coli-expressed recombinant dog ZP glycoprotein-3 (ZP3) either coupled to diphtheria toxoid or expressed as fusion protein with 'promiscuous' T non-B-cell epitope of tetanus toxoid also led to inhibition of fertility. To improve the contraceptive efficacy of ZP-based contraceptive vaccine, various groups are working on improving the immunogen, use of DNA vaccine as prime-boost strategy, and delivering the zona proteins/peptides presented on either virus-like particles or entrapped in microsphere. Host-specific live vectors such as ectromelia virus and cytomegalovirus have also been used to deliver mouse ZP3 in mice. Various studies show the enormous potential of the ZP-based vaccine for the management of wildlife population, where permanent sterilization may be desirable.