3.2 Seroprevalence and presence of viral DNA
The results obtained from the serological tests and molecular analysis for each year are shown in Table 2, Fig.1 and Fig.2. Antibodies recognising MYXV antigens were detected in 57 Iberian hares. Interestingly, 5.4% (CI95% 3.0-9.6%) of the samples randomly collected in 1994-1997, were seropositive (Table 2). In 2017, 1.7% of sera (CI95% 0.3-8.9%) were seropositive, while in 2018-2019 the seropositivity was 17.4% (CI95% 12.3-24.2%). The seropositivity in the found-dead subset of the sample was 39.1% (CI95% 22.2-59.2%), more than double than in the randomly collected sera subset.
For the samples collected between 1994-1999, only blood serum was available. Sera were diluted 1:4 in PBS prior extraction to avoid inhibition. MYXV-DNA was detected in four samples from 1994-1999 (all corresponding to seronegative hares), in very low quantities as expected (Cq values around 35.0 according with (Duarte et al., 2014)). Regarding the samples collecter over 2017-2019, higher RI10 values were associated to the qPCR positive samples (Fig. 3, green dots in left graph). Contrarily, lower values of RI10 were observed in the group of qPCR negative and non-tested hares (Fig. 3, red and blank dots in right graph).
Seropositive samples were detected in two out of the five administrative units included in the study in 1994-1999 as well as in 11 of 20 units included in 2017-2019 (Fig. 4).