Highly Pathogenic Influenza A(H5N1) Virus Survival in Complex Artificial Aquatic Biotopes

Abstract

BackgroundVery little is known regarding the persistence of Highly Pathogenic Avian Influenza (HPAI) H5N1 viruses in aquatic environments in tropical countries, although environmental materials have been suggested to play a role as reservoirs and sources of transmission for H5N1 viruses.Methodology/Principal FindingsThe survival of HPAI H5N1 viruses in experimental aquatic biotopes (water, mud, aquatic flora and fauna) relevant to field conditions in Cambodia was investigated. Artificial aquatic biotopes, including simple ones containing only mud and water, and complex biotopes involving the presence of aquatic flora and fauna, were set up. They were experimentally contaminated with H5N1 virus. The persistence of HPAI H5N1 virus (local avian and human isolates) was determined by virus isolation in embryonated chicken eggs and by real-time reverse-polymerase chain reaction. Persistence of infectious virus did not exceed 4 days, and was only identified in rain water. No infectious virus particles were detected in pond and lake water or mud even when high inoculum doses were used. However, viral RNA persisted up to 20 days in rain water and 7 days in pond or lake water. Viral RNA was also detected in mud samples, up to 14 days post-contamination in several cases. Infectious virus and viral RNA was detected in few cases in the aquatic fauna and flora, especially in bivalves and labyrinth fish, although these organisms seemed to be mostly passive carriers of the virus rather than host allowing virus replication.Conclusions/SignificanceAlthough several factors for the survival and persistence of HPAI viruses in the environment are still to be elucidated, and are particularly hard to control in laboratory conditions, our results, along with previous data, support the idea that environmental surveillance is of major relevance for avian influenza control programs.

The significance of naturally occurring neuraminidase quasispecies of H5N1 avian influenza virus on resistance to oseltamivir: a point of concern

“…The interplay between host (reservoir birds) and viral factors could have promoted the survival of the quasispecies populations found in this study in their natural habitat while the cell-based systems could not (Horm et al, 2012).…”

Accumulation and Inactivation of Avian Influenza Virus by the Filter-Feeding Invertebrate Daphnia magna

“…Aquatic environments inhabited by AIV reservoir species (i.e., waterfowl) are complex, and persistence of AIV is influenced by a combination of abiotic factors, including pH, temperature, and salinity (7,37), and biotic factors, including zooplankton, bivalves, fish, amphibians, and vegetation (21). Daphnia spp.…”

“…In contrast, zebra mussels (Dreissena polymorpha) maintained detectable amounts of viable AIV in their tissue for up to 16 days postexposure (19), and freshwater clams acted as bioconcentrators for AIV, highlighting their potential use as sentinels in AIV surveillance (20). Based on a study of H5N1 persistence in simulated complex aquatic habitats, Horm et al (21) detected infectious virus in bivalve tissue only shortly after exposure and suggested that bivalves and other aquatic fauna were passive carriers of AIV. In the first assessment of the effects of filter-feeding zooplankton on AIV persistence, Abbas et al (22) exposed Daphnia magna to AIV-dosed water and found detectable levels of virus associated with Daphnia tissue for up to 6 days postexposure.…”

Synergism between arsenic trioxide and cyclopamine in the inhibition of PC3 cell survival via the Hedgehog signaling pathway

“…Recent discoveries highlight the importance of the Hh signaling pathway in prostate growth regulation [12,48] and Hh signaling pathway inhibitors therefore would be promising agents for prostate cancer therapy [12]. However, major issues with current Hedgehog pathway inhibitors include rapid acquired resistance, severe side effects and potential developmental toxicities to use in children [49]. Furthermore, most of Hh antagonists target Smo receptor and little target the signaling components down-stream of Smo, such as fused homolog (Sufu) or GLI [50,51].…”