AMB Volume 42, Issue 2, 2026 Pages 247-252 https://doi.org/10.59393/amb26420209
Serology Studies on Contagious Ecthyma in Small Ruminants in Bulgaria
Ivanov L., Peshev R.
Comparative serological studies were performed to establish the prevalence of the virus of contagious ecthyma (CE) in small ruminants in Bulgaria, using the microvirus neutralization test (MVNT) and passive hemagglutination (PHA) on 260 serum samples obtained from animals inhabiting 12 sheep and goat farms. Fourteen serum samples from sheep and goats with characteristic clinical signs of CE, including animals vaccinated against the infection, were used to develop PHA. To determine non-specific inhibitors and hemagglutinins, the 14 serum samples were processed thermally, and with a sheep erythrocyte depot, and in this study, no non-specific hemagglutinins and PHA inhibitors were detected. А reference strain of CE “Phylaxia” was used as antigen for conducting the PHA, after concentrating with a saturated solution of ammonium sulfate. The sheep erythrocytes were found to be the most suitable for conducting PHA. When performing comparative studies of 14 serum samples by MVNT and PHA, 13 samples were found positive by using MVNT, and 14 were positive by PHA. We found an agreement of results in 13 samples, studied by MVNT and PHA. In a serological study of 260 serum samples for antibodies against the virus of CE, we found 190 positive (73.1 %) by MVNT, and 192 positive (73.8 %) by PHA. No statistically significant difference in the studies of serum samples by both tests was found. From the results obtained, it can be concluded that the PHA can be successfully used for retrospective diagnosis of CE. Both tests established a wide prevalence of CE in Bulgaria.
Keywords: Contagious ecthyma, MVNT, PHA
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