RNAlater® is a viable storage option for avian influenza sampling in logistically challenging conditions

Abstract

Surveillance of wild birds is critical in monitoring for highly pathogenic avian influenza A viruses (AIVs). However, a successful surveillance regime requires proper treatment of samples in the field - rapid placement of samples in -80°C and subsequent maintenance of cold-chain. Given the logistical difficulties of this, many avian taxa and/or geographic locations are not sampled, or, when sampled may result in false negatives due to poor sample treatment in the field. Here, we assessed the utility of RNAlater^® as a stabilization agent for AIV sampling. We found no difference in real time PCR performance between virus transport media at optimal conditions and RNAlater^® at -80°C, -20°C, 4°C or room temperature up to two weeks, at either low or high virus load. Not only was RNAlater^® useful in comparison of spiked samples or those from duck experiments, it was employed successfully in a field study of backyard birds in China. We detected AIV in cloacal and oropharyngeal samples from chickens and a sample with a low Cq was successfully subtyped as H9, although sample storage conditions were suboptimal. Thus, despite limitations in downstream characterization such virus isolation and typing, RNAlater^® is a viable option for AIV sampling under logistically challenging circumstances.

Keywords: China; Influenza A virus; RNA preservative; RNAlater(®); Storage conditions; VTM.