Detection of rabies virus in cranial cavity lavage of naturally infected bats

Abstract

The rabies virus (RABV) has been isolated in several bats species in the world, and among them, hematophagous, frugivorous and insectivorous species. Bats found in Brazil are small, which can lead to situations in which there are limitations in the collection of the central nervous system (CNS) and the amount of material may be insufficient to carry out laboratory diagnostic techniques for rabies. The objective of this work was to evaluate an alternative sample collection for the diagnosis of rabies in bats. A total of 92 bat samples, 82 positives and 10 negatives were selected. The cranial cavity was scraped with the aid of sterile tips and a virus diluent was added to create a suspension. All samples were submitted to Rabies Tissue Culture Infection Test (RTCIT) and reverse transcription polymerase chain reaction (RT-PCR). The diagnostic sensitivity and specificity of the RTCIT and RT-PCR using the cranial cavity lavage were calculated in comparison with the results of the laboratory routine (DFAT and RTCIT) performed with the CNS (considered gold standard). The results of the RTCIT show that the cranial cavity lavage is not an adequate sample for viral isolation, since the diagnostic sensitivity was low (37.8 %) when compared with the tests with the CNS. However, the RT-PCR of the cranial cavity lavage may be a tool to assist in the diagnosis, since it presented a sensitivity of 76.8 %. The results of this study suggest that cranial cavity lavage is an interesting alternative to enable the diagnosis of rabies in bats and increases the possibility of diagnosis contributing to rabies surveillance and control.

Keywords: Bats; Cranial cavity lavage; RT-PCR; RTCIT; Rabies virus.