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An abattoir survey of sheep and goats was carried out in The Gambia for one year. A total of 1248 goats and 438 sheep, predominantly young females, were slaughtered and sampled. Sixty per cent of the females of both species were pregnant. There were no significant differences between the dressing percentages of different breeds and age groups. Sex and stage of pregnancy had a significant influence on carcase yields in both species. In goats the highest carcase yields were obtained during the early dry season. Most of the animals were clinically healthy and there were few pathological findings postmortem. In both species, there was a seasonal fluctuation of packed cell volume (PCV), with a minimum during the rains, and although the prevalence of trypanosomiasis was low it reduced the PCV. Faecal egg counts of Trichostrongylidae were highest during the rainy season and goats had higher faecal egg and coccidial oocyst counts than sheep. In sheep, a breed difference was observed for PCV and an age difference for egg excretion. The peak or higher rates of egg excretion occurred during the rains in both species. The immune status against peste des petits ruminants was significantly lower in goats (39 per cent) than in sheep (49.5 per cent). Antibodies against bluetongue virus were found in 62.6 per cent of goats and 55.8 per cent of sheep.

The aetiological agent responsible for an epizootic of a rinderpest-like disease afflicting sheep and goats in three states of northern India was confirmed as peste des petits ruminants virus. To differentiate the virus from rinderpest a number of diagnostic tests were used, including immunocapture ELISA, specific oligonucleotide primers in a reverse transcriptase polymerase chain reaction, immunofluorescence with virus specific monoclonal antibodies and virus isolation. The virulence profile of one isolate in cattle sheep and goats was established. Infected animals developed specific antibody responses and excreted specific antigen in their lachrymal secretions.

A monoclonal antibody based competitive enzyme-linked immunosorbent assay (MC-ELISA) for the detection of antibodies against epizootic haemorrhagic disease of deer viruses (EHDV) is described. Test sera were competed with a monoclonal antibody against the VP7 protein of EHDV serotype 1. The assay was capable of detecting antibodies to all serotypes of EHDV but unlike the agar gel immunodiffusion (AGID) test, gave no cross-reactions with antibodies against bluetongue, Palyam or Tilligery viruses. The MC-ELISA was more sensitive than a polyclonal based ELISA reported previously (Thevasagayam et al., 1995b) and would be ideal for epidemiological surveys since it is suitable for the examination of antisera from all animal species without the need for individual anti-species enzyme conjugates.

A serogroup specific sandwich ELISA was developed for the detection of epizootic haemorrhagic disease of deer viruses (EHDV) in infected insects and tissue culture preparations. Polyclonal rabbit antiserum against purified EHDV core particles was used to capture viral antigen and specific binding detected using guinea pig antisera against EHDV core particles followed by anti-guinea pig immunoglobulin enzyme-labelled conjugate. The assay is EHDV specific and detects all 8 serotypes. No cross-reactions were found with related viruses such as bluetongue (BTV), Palyam, Tilligery or African horse sickness virus (AHSV). A similar serogroup specific sandwich ELISA was also developed for BTV. The assays showed a similar sensitivity in detecting the respective EHDV or BTV antigens in a pool of 500 midges where only 2 were infected. These assays allow a simple and rapid means of detecting and differentiating members of these closely related serogroups. The sensitivity of the tests will allow more extensive studies on vector competence and virus/vector distribution.

A competitive enzyme-linked immunosorbent assay is described for the detection of antibodies against epizootic haemorrhagic disease of deer viruses (EHDV). Test antisera were tested against a guinea-pig antiserum raised against EHDV core particles. The assay detected antibodies to all serotypes of EHDV, but unlike the agar gel immunodiffusion (AGID) test, gave no cross-reactions with antibodies against bluetongue, Palyam and Tilligery viruses. The C-ELISA would be ideal for use in epidemiological surveys since it is suitable for the examination of antisera from all susceptible species without the need for individual species-specific enzyme conjugates.