Virus hazards from food, water and other contaminated environments

Abstract

Numerous viruses of human or animal origin can spread in the environment and infect people via water and food, mostly through ingestion and occasionally through skin contact. These viruses are released into the environment by various routes including water run-offs and aerosols. Furthermore, zoonotic viruses may infect humans exposed to contaminated surface waters. Foodstuffs of animal origin can be contaminated, and their consumption may cause human infection if the viruses are not inactivated during food processing. Molecular epidemiology and surveillance of environmental samples are necessary to elucidate the public health hazards associated with exposure to environmental viruses. Whereas monitoring of viral nucleic acids by PCR methods is relatively straightforward and well documented, detection of infectious virus particles is technically more demanding and not always possible (e.g. human norovirus or hepatitis E virus). The human pathogenic viruses that are most relevant in this context are nonenveloped and belong to the families of the Caliciviridae, Adenoviridae, Hepeviridae, Picornaviridae and Reoviridae. Sampling methods and strategies, first-choice detection methods and evaluation criteria are reviewed.

Figure 1

Contamination routes for environmental virus hazards (a) of animal origin and (b) in foods. (a) Contamination routes of environmental virus hazards of animal origin. Zoonotic route of contamination from the original source (animal) to humans. (b) Environmental virus contamination of foods. Contamination from original source to humans using food and water as a route of transmission.

Figure 2

Schematic diagram of the analytical process of detection and identification of environmental virus hazards. TCDI ₅₀, median tissue culture infective dose assay; EIA, enzymatic immunoassay; RIA, radioimmunoassay; ELISA, enzyme‐linked immunosorbent assay; NASBA, nucleic acid sequence–based amplification.