per year and per 100,000 inhabitants, and the mortality is
very low (less than 0.02 %). More than 98 % of the population produces antibodies against HAV. HAV is highly resistant to heat. HEV causes hepatitis E and it was discovered in
1990. It is, as HAV, a non-enveloped virus with a positive
single-stranded RNA. It is excreted in the feces over a period
of more than 6 weeks after infection, thereby facilitating its
spread in the environment and its transmission. Contamination is foodborne and occurs mainly by drinking contaminated water. Its incidence in adults is higher than that of
HAV and is particularly harmful to pregnant women.
Mortality is higher than for HAV and can reach 2–3 %.
15.2.1.3 Rotavirus
Rotavirus is the main cause of infantile gastroenteritis
(95 % of children are infected). This non-enveloped virus
with double-stranded RNA is responsible for severe gastroenteritis in children from 4 months to 3 years. Transmission
is from person to person by fecal-oral route, through
contaminated food and water.
15.2.1.4 Norwalk Virus
Norwalk virus is non-enveloped and has a single-stranded
RNA. Like other viruses, the main reservoirs are feces.
Contamination is by fecal-oral route but also by drinking
and bathing contaminated water. It is widespread and causes
diarrhea and vomiting in infected patients. The infectious
dose appears to be very low.
Virus concentration in surface and drinking waters is
often very low due to the high dilution rate after contamination with feces. Their detection therefore often requires a
concentration step from tens of liters of water.
15.2.2 Bacteria
Bacteria are prokaryotic microorganisms (without a
differentiated nucleus) surrounded by a membrane and a cell
wall. Their size varies between 0.1 and 10 μm, and they may
have different morphologies. Two types of morphologies
dominate, coccus (spherical) and rod (cylindrical shape,
sometimes curved), and the cells can remain together in
groups or clusters. Depending on the nature of the cell wall
structure, we differentiate between Gram-negative (Gram-)
and Gram-positive (Gram+) bacteria according to the
response of bacterial cells to a special staining procedure,
the Gram stain. Some bacterial species can produce a
resistance form (the endospore) when the environment is
unfavorable, and endospores are able to remain dormant for
many years and, then, convert back to a vegetative cell when
the environment is favorable. The bacteria that multiply in the
digestive tract of humans or warm-blooded animals are called
enteric bacteria (sometimes simply called fecal bacteria).
The existence of pathogenic enteric bacteria has been
known for over a century. The main bacteria involved belong
to the genera Salmonella, Shigella, Campylobacter, Yersinia,
Escherichia coli, and Vibrio. Other pathogens such as
Legionella and some species of the genus Vibrio are not
enteric bacteria but pathogenic bacteria whose natural habitat
is the environment, especially aquatic systems. Opportunistic pathogenic* bacteria may be of fecal origin or not.
They belong to a variety of types of bacteria such as Pseudomonas, Aeromonas, Klebsiella, Flavobacterium, Enterobacter, Citrobacter, Serratia, Acinetobacter, Proteus,
Providencia and Mycobacterium, and Nocardia. Infections
by opportunistic pathogens mainly concern newborns, the
elderly, immunocompromised persons*, and persons
hospitalized. Several organizations such as nosocomial infection prevention centers and foundations that assist individuals
with cystic fibrosis organize or promote the structuring of
monitoring networks for opportunistic infections.
Below is a brief description of some pathogenic bacteria,
but we recommend consulting the following website for
more comprehensive information regarding waterborne
pathogens: http://www.hc-sc.gc.ca/ewh-semt/pubs/watereau/pathogens-pathogenes/index-eng.php.
Salmonella is a very important genus that brings together
more than 2,400 different serotypes. All serotypes are pathogenic for humans. They belong to the family Enterobacteriaceae and are responsible for salmonellosis. The disease
results in acute gastroenteritis caused by ingestion of a dose
that varies depending on the person, from 10 to 10
7 bacterial
cells. There are healthy carriers of Salmonella. Transmission
is by fecal-oral route, food consumption directly or indirectly (seafood) contaminated, or by direct contact with
infected animals. Salmonella paratyphi and Salmonella
typhi are only found in humans. S. paratyphi is responsible
for gastroenteritis and paratyphoid fever. The infectious
dose (ID 50 ) is approximately 1,000 cells, and contamination
occurs through ingestion of contaminated food or water
after incubation for 6–72 h. The ID 50 is 100,000 for
S. typhi infection and leads to typhoid fever after 7–28
days of incubation. Transmission is similar to S. paratyphi,
but the incubation is from 1 to 10 days.
Cattle and poultry farms are Salmonella reservoirs in
the environment, and they contribute together with the wastewater discharges to the contamination of aquatic ecosystems.
Contamination of oysters in shellfish farming areas is often
linked to Salmonella inputs via the discharge of surface waters.
Shigella also belongs to the family of Enterobacteriaceae
and is responsible for shigellosis. This disease, also called
“bacillary dysentery,” results in pain in the colon and in the
small intestine, with severe diarrhea, fever, and nausea.
The disease affects humans and primates and requires the
ingestion of 10 and 200 bacterial cells to be triggered
after incubation for 1–7 days. Contamination occurs directly
or indirectly by fecal-oral route or by contaminated water
(drinking water and recreational water). There are healthy
carriers of the germ.
622
P. Lebaron et al.
very low (less than 0.02 %). More than 98 % of the population produces antibodies against HAV. HAV is highly resistant to heat. HEV causes hepatitis E and it was discovered in
1990. It is, as HAV, a non-enveloped virus with a positive
single-stranded RNA. It is excreted in the feces over a period
of more than 6 weeks after infection, thereby facilitating its
spread in the environment and its transmission. Contamination is foodborne and occurs mainly by drinking contaminated water. Its incidence in adults is higher than that of
HAV and is particularly harmful to pregnant women.
Mortality is higher than for HAV and can reach 2–3 %.
15.2.1.3 Rotavirus
Rotavirus is the main cause of infantile gastroenteritis
(95 % of children are infected). This non-enveloped virus
with double-stranded RNA is responsible for severe gastroenteritis in children from 4 months to 3 years. Transmission
is from person to person by fecal-oral route, through
contaminated food and water.
15.2.1.4 Norwalk Virus
Norwalk virus is non-enveloped and has a single-stranded
RNA. Like other viruses, the main reservoirs are feces.
Contamination is by fecal-oral route but also by drinking
and bathing contaminated water. It is widespread and causes
diarrhea and vomiting in infected patients. The infectious
dose appears to be very low.
Virus concentration in surface and drinking waters is
often very low due to the high dilution rate after contamination with feces. Their detection therefore often requires a
concentration step from tens of liters of water.
15.2.2 Bacteria
Bacteria are prokaryotic microorganisms (without a
differentiated nucleus) surrounded by a membrane and a cell
wall. Their size varies between 0.1 and 10 μm, and they may
have different morphologies. Two types of morphologies
dominate, coccus (spherical) and rod (cylindrical shape,
sometimes curved), and the cells can remain together in
groups or clusters. Depending on the nature of the cell wall
structure, we differentiate between Gram-negative (Gram-)
and Gram-positive (Gram+) bacteria according to the
response of bacterial cells to a special staining procedure,
the Gram stain. Some bacterial species can produce a
resistance form (the endospore) when the environment is
unfavorable, and endospores are able to remain dormant for
many years and, then, convert back to a vegetative cell when
the environment is favorable. The bacteria that multiply in the
digestive tract of humans or warm-blooded animals are called
enteric bacteria (sometimes simply called fecal bacteria).
The existence of pathogenic enteric bacteria has been
known for over a century. The main bacteria involved belong
to the genera Salmonella, Shigella, Campylobacter, Yersinia,
Escherichia coli, and Vibrio. Other pathogens such as
Legionella and some species of the genus Vibrio are not
enteric bacteria but pathogenic bacteria whose natural habitat
is the environment, especially aquatic systems. Opportunistic pathogenic* bacteria may be of fecal origin or not.
They belong to a variety of types of bacteria such as Pseudomonas, Aeromonas, Klebsiella, Flavobacterium, Enterobacter, Citrobacter, Serratia, Acinetobacter, Proteus,
Providencia and Mycobacterium, and Nocardia. Infections
by opportunistic pathogens mainly concern newborns, the
elderly, immunocompromised persons*, and persons
hospitalized. Several organizations such as nosocomial infection prevention centers and foundations that assist individuals
with cystic fibrosis organize or promote the structuring of
monitoring networks for opportunistic infections.
Below is a brief description of some pathogenic bacteria,
but we recommend consulting the following website for
more comprehensive information regarding waterborne
pathogens: http://www.hc-sc.gc.ca/ewh-semt/pubs/watereau/pathogens-pathogenes/index-eng.php.
Salmonella is a very important genus that brings together
more than 2,400 different serotypes. All serotypes are pathogenic for humans. They belong to the family Enterobacteriaceae and are responsible for salmonellosis. The disease
results in acute gastroenteritis caused by ingestion of a dose
that varies depending on the person, from 10 to 10
7 bacterial
cells. There are healthy carriers of Salmonella. Transmission
is by fecal-oral route, food consumption directly or indirectly (seafood) contaminated, or by direct contact with
infected animals. Salmonella paratyphi and Salmonella
typhi are only found in humans. S. paratyphi is responsible
for gastroenteritis and paratyphoid fever. The infectious
dose (ID 50 ) is approximately 1,000 cells, and contamination
occurs through ingestion of contaminated food or water
after incubation for 6–72 h. The ID 50 is 100,000 for
S. typhi infection and leads to typhoid fever after 7–28
days of incubation. Transmission is similar to S. paratyphi,
but the incubation is from 1 to 10 days.
Cattle and poultry farms are Salmonella reservoirs in
the environment, and they contribute together with the wastewater discharges to the contamination of aquatic ecosystems.
Contamination of oysters in shellfish farming areas is often
linked to Salmonella inputs via the discharge of surface waters.
Shigella also belongs to the family of Enterobacteriaceae
and is responsible for shigellosis. This disease, also called
“bacillary dysentery,” results in pain in the colon and in the
small intestine, with severe diarrhea, fever, and nausea.
The disease affects humans and primates and requires the
ingestion of 10 and 200 bacterial cells to be triggered
after incubation for 1–7 days. Contamination occurs directly
or indirectly by fecal-oral route or by contaminated water
(drinking water and recreational water). There are healthy
carriers of the germ.
622
P. Lebaron et al.