Bovine Pestivirus Heterogeneity and Its Potential Impact on Vaccination and Diagnosis

Abstract

Bovine Pestiviruses A and B, formerly known as bovine viral diarrhoea viruses (BVDV)-1 and 2, respectively, are important pathogens of cattle worldwide, responsible for significant economic losses. Bovine viral diarrhoea control programmes are in effect in several high-income countries but less so in low- and middle-income countries where bovine pestiviruses are not considered in disease control programmes. However, bovine pestiviruses are genetically and antigenically diverse, which affects the efficiency of the control programmes. The emergence of atypical ruminant pestiviruses (Pestivirus H or BVDV-3) from various parts of the world and the detection of Pestivirus D (border disease virus) in cattle highlights the challenge that pestiviruses continue to pose to control measures including the development of vaccines with improved cross-protective potential and enhanced diagnostics. This review examines the effect of bovine pestivirus diversity and emergence of atypical pestiviruses in disease control by vaccination and diagnosis.

Vaccination of Sheep with Bovine Viral Diarrhea Vaccines Does Not Protect against Fetal Infection after Challenge of Pregnant Ewes with Border Disease Virus

“…In contrast to the NS3 ELISA response, all BVDV vaccines were able to induce a similar neutralizing antibody response against BDVD1a NADL strain after immunization of sheep, regardless of the genotypes 1a (Mucosiffa, Bovilis) or 1b (Bovela) of the vaccine strains. Induced detectable levels of cross-reacting antibodies against at least one other subgenotype have been previously described after BVDV-1 vaccination in cattle (for review, [ 37 ]) and BDV infection of sheep [ 9 , 11 , 16 ]. Our results however differ from those of Sozzi et al who showed that the BVDV-1b vaccine strain of Bovela did not induce neutralizing antibodies against the BVDV-1a NADL strain after immunization of cattle [ 38 ].…”

“…The genetic and antigenic diversity of pestiviruses is well known and well documented in the literature. A good cross-protection has been observed within the wide range of BVDV-1 genotypes, as was cross-protection against BVDV-2 using BVDV-1 based MLV vaccines [ 37 , 39 ]. However, the inability to fully prevent fetal infection, postnatal infection, and virus shedding has, in part at least, been attributed to antigenic diversity [ 40 , 41 , 42 ].…”

“…In this study, we did not investigate the CD4+ and CD8+ T-cell immune response, which was speculated in cattle to also drive the clinical cross-protection at least observed by Pestivirus A vaccines [ 37 ]. The cytotoxic CD8+ response eliminates BVDV infected cells while CD4+ T helper cells are key players in the development of protective humoral and cellular immunity against the virus.…”

“…On the other hand, E2 is also the main target for neutralizing antibody response which was shown to cross-react in this study, albeit neutralizing and T-cell epitopes of E2 are different. In addition, the highly conserved NS3 is known to induce cross-reactivity for T-cells and will probably generate recall T cell responses at least in sheep vaccinated with the two MLV vaccines [ 37 ]. The role of the cellular response for the prevention of BDV fetal infection remains to be determined, especially whether BDV crosses the synepitheliochorial ovine placenta in the form of free virus and/or through the passage of infected cells.…”

Bovine Viral Diarrhea Virus (BVDV): A Preliminary Study on Antiviral Properties of Some Aromatic and Medicinal Plants

“…Despite the infections ofthis pathogen havingthe highest impact on livestock worldwide [ 1 , 11 ], it is still the case that neither effective vaccines nor selective antiviral drugs are available [ 12 , 13 ].…”