A new phylogenetic lineage of rabies virus associated with western pipistrelle bats (Pipistrellus hesperus).

Bats represent the major source of human rabies cases in the New World. In the USA, most cases are associated with species that are not commonly found or reported rabid. To understand better the epidemiology and public health significance of potentially important bat species, a molecular study was performed on samples collected from naturally infected rabid western pipistrelle (Pipistrellus hesperus), eastern pipistrelle (Pipistrellus subflavus) and silver-haired bats (Lasionycteris noctivagans) from different regions of their geographical distribution in the USA. A 264 bp fragment at the 5' end of the N gene coding region was sequenced and analysed in comparison with rabies virus variants circulating within other North American mammals. Phylogenetic analysis demonstrated that P. hesperus bats maintain a unique rabies virus variant. Preliminary data also suggest that P. subflavus and Lasionycteris noctivagans may harbour two different rabies virus variants (Ps and Ln) that are likely to be maintained independently by each bat species, which recently appear to have emerged as major vectors of human disease.

A novel technique to eliminate cross-contamination when making wells on slides for rabies diagnosis.

The direct fluorescent antibody (DFA) rabies diagnostic test requires demarcating desirable areas of brain tissue slip smear slides to be stained, traditionally achieved by applying paint from a tech pen or using a wax pencil to form a circle or dam-like ring or well into which rabies conjugate is expelled. Unfortunately, using these instruments poses a possibility of cross-contamination by transfer via the pen or pencil tip of rabies antigen from one slide to another. A new method was developed to avoid cross-contamination. The open end of a disposable glass test tube, dipped into a shallow reservoir of nail polish, was used to apply a dam-like ring about the slip smear area to be stained, after which the test tube was discarded, thereby precluding tissue transfer.