Microbiological Coastal Risks and Monitoring Systems - Vulnerability of Coastal Ecosystems and Adaptation - page 101

These diseases include those in which infections are linked to
coastal environments, whether the transmission is hydric, vectorial or
via food. The available data do not give the proportion of DALY
caused by these infections, since very often there are no
epidemiological studies refined enough to determine the cause of
diarrhea or infections following consumption of sea produce or
contact with water.

Some studies have enabled the DALY of infections linked to
marine environments polluted by used water to be estimated
[SHU 05]. These studies estimate a DALY of 180,000 days per year
caused by respiratory infections (Ear, Nose and Throat (ENT)) and the
gastroenteritis associated with bathing in seawater of acceptable
quality (European and US norms). This estimation shows the low rate
of infections by microorganisms of fecal origin transmitted during
recreational activities in contaminated seawater.

The results of the estimation for hepatitis A and E transmitted
through the consumption of raw shellfish give a DALY of 2.9 million
days per year. This approach, even if it remains approximate, shows
the significance of infectious diseases transmitted by marine
environments. It certainly underestimates the reality of these diseases,
since it does not take account of other pathogenic agents, such as viral
gastroenteritis and vibriosis (apart from cholera), transmitted through
the consumption of shellfish and raw or slightly cooked sea produce.

3.2.2. Environmental change and modifications in the

epidemiological environment

3.2.2.1. Climate change
Climate change affects the distribution and incidence of infectious
diseases through the effects of different modifications of
environmental factors. Thus, the increase in air or water temperature
favors the dispersion of pathogens or vectors from tropical zones to
temperate zones. This is the case with bacteria of the Vibrio genus,
pathogens in humans and aquatic animals, or certain mosquito vectors
of malarial agents, dengue fever and chikungunya [GIT 01, VEZ 13].