Retrospective serological study on bluetongue antibody prevalence in a Louisiana herd

Abstract

Previous studies on the prevalence of bluetongue antibodies in south-eastern Louisiana herds, essentially Louisiana State University herds, since 1978 indicate that her6 prevalence rates averaged 55% and for animals of two years of age or more were within the 50 to 100% range (Fulton, Nicholson, Pearson, Potter, Archibald, Pearson and Jochin, 1982). The overall prevalence of bluetongue antibodies for the State of Louisiana as determined in 1980 to 1981 is 28%. Data are not available for the period prior to 1978. At the time the sera from Louisiana State University herds was collected during 1957 to 1962 no test was available for sero-epidemiological studies. This sera was originally collected by E. Roth as part of a leptospirosis study, stored at -18~ rescued and organised into a serum bank in 1979 to 1980. This study was carried out to determine the differences, if any, in antibody prevalences in LSU herds as currently reported. All sera used were derived from this collection and three separate test runs were conducted. The first test was carried out upon 121 samples derived from the LSU dairy herd and randomly selected from three age groups: four to 12 months; 13 to 24 months; and 25+ months of age, each in two periods of time 1957 to 1959 inclusive and 1960 to 1962 inclusive. The purpose of structuring the sample in this way was to obtain indicators of the prevalence rates in each of these six categories which were to be used as guidelines for selection of further samples for more detailed investigation. As all results from the first test were negative a second test was carried out involving 112 randomly selected samples from older animals in three herds. Two of these samples proved positive and a third test run of 67 serum samples was conducted concentrating upon older animals sampled during the period 1957 to 1959. Details of the structuring of the three samples are given in Table I. Subsequently a search was made for other sera from positive animals. Four further samples from one animal were found and tested. A microgel diffusion technique (Fulton et al, 1982) was conducted for all samples using an antigen and control antiserum. 4 All plates were read after 24h; the bovine serum was used undiluted. Two of the 300 sera tested were found to be positive. One of these was collected on 9 September 1958 from a 12t/z year old Guernsey cow (cow 2) in the LSU dairy herd. Sera collected from the same

DOI: 10.1007/BF02356969

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Cite this paper

@article{Hughjones1985RetrospectiveSS, title={Retrospective serological study on bluetongue antibody prevalence in a Louisiana herd}, author={M Hugh-jones and Peter D. Moorhouse and Robert W. Fulton}, journal={Tropical Animal Health and Production}, year={1985}, volume={17}, pages={180-182} }