European bat lyssavirus in Scottish bats

Abstract

We report the first seroprevalence study of the occurrence of specific antibodies to European bat lyssavirus type 2 (EBLV-2) in Daubenton's bats. Bats were captured from 19 sites across eastern and southern Scotland. Samples from 198 Daubenton's bats, 20 Natterer's bats, and 6 Pipistrelle's bats were tested for EBLV-2. Blood samples (N = 94) were subjected to a modified fluorescent antibody virus neutralization test to determine antibody titer. From 0.05% to 3.8% (95% confidence interval) of Daubenton's bats were seropositive. Antibodies to EBLV-2 were not detected in the 2 other species tested. Mouth swabs (N = 218) were obtained, and RNA was extracted for a reverse transcription-polymerase chain reaction (RT-PCR). The RT-PCR included pan lyssavirus-primers (N gene) and internal PCR control primers for ribosomal RNA. EBLV-2 RNA was not detected in any of the saliva samples tested, and live virus was not detected in virus isolation tests.

Figure 1

Distribution of Daubenton's bats in the United Kingdom and Ireland showing 5 cases of infection with European Bat lyssavirus type 2 (EBLV-2). Open circles are sites where Daubenton's bats were observed away from their roosts, and the closed circles are roosts of Daubenton's bats (summer and winter). The 5 numbered gray circles are sequential sites where EBLV-2–positive cases were found. Reprinted with permission of The Bat Conservation Trust (London, United Kingdom) from Distribution of Bats in Britain and Ireland 1980–1999.

Figure 2

Bat sampling locations in southern and eastern Scotland. The circles indicate both the location (number) and an estimate of the number (size) of bats sampled.

Figure 3

Antibody titers to European bat lyssavirus type 2 (EBLV-2) in bat sera from Scotland. An EBLV-2–specific modified fluorescent antibody virus neutralization (mFAVN) test was used to determine the level of circulating antibody in Daubenton's bats from 19 sites in Scotland. The test uses a 3-fold dilution series (9, 27, 81, 243, etc.) and the positive/negative cutoff is a titer (reciprocal dilution) of 27. Circles on the graph represent either single serum samples or pools of sera (88 for Daubenton's bats, 5 for Natterer's bats, and 1 from Pipistrelle's bats). All titers >27 are Daubenton's bats from 2 sites (5 from site 1 and 1 from site 15). No data were available for sites 2, 17, and 19.