Screening of Active Lyssavirus Infection in Wild Bat Populations by Viral RNA Detection on Oropharyngeal Swabs

Abstract

Brain analysis cannot be used for the investigation of active lyssavirus infection in healthy bats because most bat species are protected by conservation directives. Consequently, serology remains the only tool for performing virological studies on natural bat populations; however, the presence of antibodies merely reflects past exposure to the virus and is not a valid marker of active infection. This work describes a new nested reverse transcription (RT)-PCR technique specifically designed for the detection of the European bat virus 1 on oropharyngeal swabs obtained from bats but also able to amplify RNA from the remaining rabies-related lyssaviruses in brain samples. The technique was successfully used for surveillance of a serotine bat (Eptesicus serotinus) colony involved in a case of human exposure, in which 15 out of 71 oropharyngeal swabs were positive. Lyssavirus infection was detected on 13 oropharyngeal swabs but in only 5 brains out of the 34 animals from which simultaneous brain and oropharyngeal samples had been taken. The lyssavirus involved could be rapidly identified by automatic sequencing of the RT-PCR products obtained from 14 brains and three bat oropharyngeal swabs. In conclusion, RT-PCR using oropharyngeal swabs will permit screening of wild bat populations for active lyssavirus infection, for research or epidemiological purposes, in line not only with conservation policies but also in a more efficient manner than classical detection techniques used on the brain.

Twenty years of active bat rabies surveillance in Germany: a detailed analysis and future perspectives

“…With more than 4000 oropharyngeal swabs and 1200 blood samples tested by RT-PCR and RFFIT, respectively, this is one of the most extensive active bat rabies surveillance studies ever conducted in Europe. While in several European studies no EBLVspecific RNA was detected in oropharyngeal swabs [6], we found seven oropharyngeal swab samples positive for EBLV-1 by RT-PCR which is in accordance with previous reports from Spain, UK and Switzerland [13,20,24,25]. The majority of RT-PCR-positive results were associated with E. serotinus bats, the natural reservoir host of EBLV-1.…”

“…At the serotine bat colony level (Hartmannsdorf, Brandenburg) the percentage of qRT-PCR-positive swabs reached 4·7%. In contrast, up to 21% RT-PCR-positive results were reported from a Spanish serotine bat colony targeted after the detection of a bat rabies case during passive surveillance [24]. In our study, repeated detection of viral RNA in saliva swabs from recaptured serotine bats (E. serotinus) was not observed.…”

“…The use of molecular techniques, e.g. RT-PCR, for the detection of bat lyssavirus-specific RNA was first applied in Europe [24]. So far, active bat rabies surveillance has been conducted in eight European countries (for review see [6]) including Germany, which implemented active bat rabies surveillance of free-ranging bat colonies in addition to the already established passive bat rabies surveillance system in 1993 [40].…”

Mitochondrial DNA signatures at different spatial scales: from the effects of the Straits of Gibraltar to population structure in the meridional serotine bat (Eptesicus isabellinus)

“…With maternity colonies behaving as closed communities, a pattern of epidemiological circulation by fast-spreading viral waves-as is typical in other viruses-is unlikely to occur. In fact, given that E. isabellinus bats can survive after infection (Pérez-Jordá et al, 1995;Echevarría et al, 2001), vertical transmission within bat colonies (mother-offspring) would be the most likely way for the virus to spread, with only occasional transmission between colonies caused by individual interactions between females and males (for example, mating) at the end of the reproductive season and when maternity colonies disaggregate. Although EBLV-1 has not yet been found in Africa (only around 50 E. isabellinus tested to date), we predict that Eptesicus from Northern Morocco will also carry the rabies virus and that its strains will be very similar to the EBLV-1 rabies strains found in Andalusia.…”

Australian bat lyssavirus infection in two horses

“…Although FAT is the gold standard assay for the identification of lyssavirus in tissues, in recent years advances in molecular diagnostics have seen wide use of conventional and realtime RT-PCR for the diagnosis of lyssavirus infections (Banyard et al, 2009;Black et al, 2002;Echevarría et al, 2001;Foord et al, 2006;Smith et al, 2002 Until recently, the only cases of lyssavirus infection recorded in Australia were in bats and humans. However, in May 2013 two horses were diagnosed with ABLV and are the first confirmed Australian field infections.…”