Thomann, Beat; Falzon, Laura Cristina; Bertoni, Giuseppe; Vogt, Hans-Rudolf; Schüpbach, Gertraud; Magouras, Ioannis (2017). A census to determine the prevalence and risk factors for caprine arthritis-encephalitis virus and visna/maedi virus in the Swiss goat population. Preventive veterinary medicine, 137(Pt A), pp. 52-58. Elsevier 10.1016/j.prevetmed.2016.12.012
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Thomann et al. - 2017 - A census to determine the prevalence and risk factors for caprine arthritis-encephalitis virus and visnamaedi vi.pdf - Published Version Restricted to registered users only Available under License Publisher holds Copyright. Download (1MB) |
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PREVET-16-270R2.pdf - Accepted Version Available under License Creative Commons: Attribution-Noncommercial-No Derivative Works (CC-BY-NC-ND). Download (2MB) | Preview |
In Switzerland, viruses belonging to two different phylogenetic groups of small ruminant lentiviruses (SRLV) are currently circulating: the caprine arthritis-encephalitis virus (CAEV) and visna/maedi virus (VMV). In the past two decades, a mandatory national control program has led to a very low preva- lence of seropositivity, while completely eliminating CAE as a clinical manifestation. However, in order to reduce the high costs and effort associated with this program, adjustments based on the most recent epidemiological knowledge are needed. The purpose of this study was to estimate the seroprevalence of CAEV and VMV using the newest diagnostic tools available, and to identify potential risk factors for infection with these viruses in Switzerland. For the prevalence estimation, a census was carried out including 10,696 farms with a total of 85,454 goats. Blood samples were analysed using a 3-step sero- logical testing algorithm consisting of Chekit ELISA, Western Blot and SU5 ELISA. A risk factor analysis was conducted using logistic regression models built with data obtained from a mail questionnaire, and serological results from the census. The apparent herd-level prevalences were 0.38%, 2.77%, and 3.04% for CAEV, VMV and SRLV, respectively. Animal-level prevalences were 0.06% for CAEV, 0.55% for VMV, and 0.61% for SRLV. No statistically significant risk factors associated with CAEV or VMV infection were identified. However, the proportional high number of CAEV seropositive dwarf goats, in relation to their population size, could indicate that these hobby breeds may slip through some of the official controls. For an infection with SRLV, a medium herd size (7–40 goats) was found to be protective, compared with smaller (OR = 1.90, p = 0.034) and larger herds (OR = 1.95, p = 0.038). In conclusion, considering that all CAEV positive animals were culled, these results imply that CAEV is no longer actively spreading and has successfully been controlled in Switzerland. However, given the uncertain pathogenic potential of VMV in goats, future surveillance should also be taking into account the not insignificant number of VMV circulating in the Swiss goat population.