Blocking enzyme-linked immunosorbent assay for detection of antibodies against bovine enterovirus

Use of ELISA procedures for the detection of Derzsy's disease virus of geese and of antibodies produced against it

We have developed a double antibody sandwich (antigen capture) ELISA for the detection of Derzsy's disease virus (GPV-1) antigen produced in cell cultures. This provided unambiguous quantification of virus whereas evaluation of cytopathic effect was sometimes difficult. A blocking ELISA was developed to quantify anti-GPV-1 antibodies in goose sera. This method was rapid, simple, easily standardized and correlated well with a virus neutralization test.

Survey of bovine enterovirus in biological and environmental samples by a highly sensitive real-time reverse transcription-PCR

Animal enteroviruses shed in the feces of infected animals are likely environmental contaminants and thus can be used as indicators of animal fecal pollution. Previous work has demonstrated that bovine enterovirus (BEV) present in bovine feces contaminates waters adjacent to cattle herds and that BEV-like sequences are also present in shellfish and in deer feces from the same geographical area. However, little information is available about the prevalence, molecular epidemiology, and genomic sequence variation of BEV field isolates. Here we describe an optimized highly sensitive real-time reverse transcription-PCR method to detect BEV RNA in biological and environmental samples. A combination of the amplification procedure with a previously described filtration step with electropositive filters allowed us to detect up to 12 BEV RNA molecules per ml of water. The feasibility of using the method to detect BEV in surface waters at a high risk of fecal pollution was confirmed after analysis of water samples obtained from different sources. The method was also used to study the prevalence of BEV in different cattle herds around Spain, and the results revealed that 78% (78 of 100) of the fecal samples were BEV positive. BEV-like sequences were also detected in feces from sheep, goats, and horses. Nucleotide sequence analyses showed that BEV isolates are quite heterogeneous and suggested the presence of species-specific BEV-like variants. Detection of BEV-like sequences may help in the differentiation and characterization of animal sources of contamination.

Bovine enteroviruses as indicators of fecal contamination

Surface waters frequently have been contaminated with human enteric viruses, and it is likely that animal enteric viruses have contaminated surface waters also. Bovine enteroviruses (BEV), found in cattle worldwide, usually cause asymptomatic infections and are excreted in the feces of infected animals in large numbers. In this study, the prevalence and genotype of BEV in a closed herd of cattle were evaluated and compared with BEV found in animals in the immediate environment and in environmental specimens. BEV was found in feces from 76% of cattle, 38% of white-tailed deer, and one of three Canada geese sharing the same pastures, as well as the water obtained from animal watering tanks, from the pasture, from streams running from the pasture to an adjacent river, and from the river, which emptied into the Chesapeake Bay. Furthermore, BEV was found in oysters collected from that river downstream from the farm. These findings suggest that BEV could be used as an indicator of fecal pollution originating from animals (cattle and/or deer). Partial sequence analysis of the viral genomes indicates that different viral variants coexist in the same area. The possibility of identifying the viral strains found in the animals and in the contaminated areas by sequencing the RNA genome, could provide a tool to find the origin of the contamination and should be useful for epidemiological and viral molecular evolution studies.

Epitopes on 14S subunits, natural empty capsids and virions of bovine enteroviruses

Eighteen monoclonal antibodies were produced against three Australian bovine enterovirus serogroups. Based on their binding patterns to 14S subunits, natural empty capsids and virions of 4 selected viral isolates (K2577, SL305, 66/27, J2129) in two types of quantitative ELISAs, the 18 antibodies were shown to belong to four groups. Due to the specific reaction of monoclonal antibodies, the four groups likely react with four epitopes. The first epitope was shown mainly on the surface of isolate K2577. The second and the third epitopes were common epitopes shared by all four isolates. These epitopes presented equally well on 14S subunits, natural empty capsids and virions. The fourth epitope was present mainly on the natural empty capsids and shared by most, but not all isolates. The four epitopes seem to be conformation dependent epitopes.