Microbiological Coastal Risks and Monitoring Systems - Vulnerability of Coastal Ecosystems and Adaptation - page 97

3.2.1. Pathogenic agents
The aim of the following sections is not to cover the whole
spectrum of infectious and parasitic maladies and their agents (viruses,
bacteria, protozoa and helminthes), nor to describe their cycles, but to
give some examples illustrating the principal modes of contamination;
this is to better understand the potential impacts of global
environmental changes on their epidemiological dynamics.
3.2.1.1. Virus
Numerous viruses pathogenic to humans are associated with
gastroenteritis (norovirus, rotavirus, etc.), hepatitis (virus for hepatitis
A or E), poliomyelitis and various infections (enterovirus) [BOS 05].
They are transmitted via the oral-fecal route through the water or
contaminated food products. Contamination in humans through the
marine environment essentially occurs through the consumption of
shellfish following contamination of the marine environment by
emissions from urban effluent. The survival of these viruses depends
on different factors, such as temperature, solar radiation and
adsorption. Even if these viruses are more or less broken down in the
marine environment, the elevated quantities of the virus ejected permit
the contamination of shellfish, which, through their significant
capacity for filtration, will retain and concentrate the virus.
Other viruses are transmitted by mosquitoes, causing diseases such
as dengue fever, chikungunya, Japanese encephalitis and West Nile
Fever. The development of these mosquitoes requires concentrations
of water for their larval stages, making the waters of deltas or coastal
lagoons favorable locations for their proliferation, like continental
waters [PON 07, RAM 12].
3.2.1.2. Bacteria
Pathogenic enteric bacteria are found in the marine environment
following emissions of urban effluent, such as Salmonella , Shigella
and certain E. coli enteropathogens, responsible for gastroenteritis of
varying severity, or typhoid in the case of Salmonella typhi . The
transmission is oral-fecal, and the consumption of shellfish is
responsible for most contaminations [GIR 08]. The survival of enteric