Table of Contents
Influenza Research and Treatment
Volume 2012 (2012), Article ID 912326, 11 pages
http://dx.doi.org/10.1155/2012/912326
Research Article

Persistence of Avian Influenza Viruses in Various Artificially Frozen Environmental Water Types

1Laboratory of Zoonoses, School of Veterinary Medicine, Kitasato University, 35-1 Higashi 23 Bancho, Towada, Aomori 034, Japan
2Animal Health Research Division, Bangladesh Livestock Research Institute, Savar, Dhaka 1341, Bangladesh
3Laboratory of Animal Health, Department of Veterinary Medicine, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan

Received 17 May 2012; Revised 10 August 2012; Accepted 28 August 2012

Academic Editor: Michael L. Perdue

Copyright © 2012 Dany Shoham et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. This study investigates the viable persistence of avian influenza viruses (AIVs) in various types of artificially frozen environmental water and evaluates the feasibility of similar occurrence taking place in nature, and allowing for prolonged abiotic virus survival, with subsequent biotic viral recirculation. Methods. Fresh, brackish, and salty water, taken in Japan from aquatic biotopes regularly visited by migratory waterfowl, were seeded with AIVs. We monthly monitored the viability of the seeded viruses in the frozen state at −20°C and −30°C, for 12 months. We also monitored virus viability following repeatedly induced freezing and thawing. Results. The viruses exhibited considerable viable persistence all along that period of time, as well as during freezing-thawing cycles. Appreciable, yet noncrucial variances were observed in relation to some of the parameters examined. Conclusions. As typical waterborne pathogens of numerous northerly aquatic birds, AIVs are innately adapted to both the body temperature of their hosts (40°C to 42°C) and, presumably, to subzero temperatures of frozen lakes (down to −54°C in parts of Siberia) occupied and virus-seeded by subclinically infected birds, prior to freezing. Marked cryostability of AIVs appears to be evident. Preservation in environmental ice has significant ecophylogenetic and epidemiological implications, potentially, and could account for various unexplained phenomena.