fungal pathogens within the WWTP microbiome, over the 236 sampling days. In the
WWTPs, some pathogenic fungi are of a great interest, they can be a serious threat to
human health and an issue of concern because fungi are not completely removed by
conventional WWTP and they are not included in regulatory frameworks. Furthermore, some species may produce mycotoxins, which are toxic to humans. These
pathogenic fungi may have also a significant impact on crop and plant life, affecting
food security and the whole ecosystem [43].
Cysticercosis is a parasitic infection caused by larvae of Taenia solitary worms. In
Europe and in cold or temperate regions, the species Taenia saginata is predominant.
In Africa, we find Taenia solium. These worms are most commonly found in cattle
and pigs respectively, and may infect humans. They may pose a serious risk of ocular
or neurological damage. The problem posed by Taenia is that its eggs are particularly resistant and can survive the different treatments of sewage sludge [56]. This is
why the persistence of helminth eggs is a criterion taken into account in the law of
1998 on the approval of sewage sludge as fertilizer. The transmission of worms is the
consequence of sludge spreading on plots intended for pig, sheep, or cattle breeding.
Ascariasis is a parasitic infection caused by the nematode worm Ascaris parasitizing
the small intestine of mammals. Ascaris lumbricoides is found in sewage sludge, and
its eggs contaminate the soil and plants after sludge spreading, resulting in the
infection of any organism that consumes them [1]. A. lumbricoides is the largest
intestinal roundworm and is the most common helminth infection of humans worldwide. Infestation can cause morbidity by compromising human nutritional status
[57] or affecting cognitive processes [58] inducing tissue reactions such as granuloma to larval stages and causing intestinal obstruction, which can be fatal. This
worm weakens its host by eating the ingested nutrients. Knowing that this worm is
particularly virulent in the tropics, it causes problems of undernutrition in countries
having trouble feeding. Thus, it decreases the hosts’ immune defenses making them
vulnerable to other diseases. In endemic areas, massive infections (200 to 1,000
worms) cause serious damage including intestinal obstruction that can lead to death.
The worms in abundance eventually cross the intestinal wall to spread throughout
the body and cause multiple problems (irritation, lesions, and edema). Hookworms
Ancylostoma duodenale and Necator americanus are two nematodes parasitizing
mammalian duodenum and jejunum. As with most parasitic nematode worms, they
cause skin lesions, respiratory irritation and lack of nutrition with inflammation of
the intestine. However, hookworms differ from other intestinal helminthiases in
attacking male adults rather than children. Giardiasis is also an intestinal disease,
including diarrhea, caused by Giardia intestinalis, a flagellated protozoan [59]. This
parasite can form cysts that are particularly resistant to WW treatment. It can be
transmitted to humans by non-potable water or by ingestion of contaminated food. In
the case of sewage sludge, it can be transferred to livestock after soil sludge
application. Giardia is asymptomatic most of the time. However, it can cause
diarrhea from a certain concentration of parasites. These diarrheas can become
serious when the protozoan is present at high quantity. A recent study by Amorós
et al. [60] in raw and treated sewage sludge showed that Cryptosporidium oocysts
and Giardia cysts were present in 26 of the 30 samples (86.6%) of raw sludge
Environmental, Economic, and Ethical Assessment of the Treated Wastewater and. . .
63
WWTPs, some pathogenic fungi are of a great interest, they can be a serious threat to
human health and an issue of concern because fungi are not completely removed by
conventional WWTP and they are not included in regulatory frameworks. Furthermore, some species may produce mycotoxins, which are toxic to humans. These
pathogenic fungi may have also a significant impact on crop and plant life, affecting
food security and the whole ecosystem [43].
Cysticercosis is a parasitic infection caused by larvae of Taenia solitary worms. In
Europe and in cold or temperate regions, the species Taenia saginata is predominant.
In Africa, we find Taenia solium. These worms are most commonly found in cattle
and pigs respectively, and may infect humans. They may pose a serious risk of ocular
or neurological damage. The problem posed by Taenia is that its eggs are particularly resistant and can survive the different treatments of sewage sludge [56]. This is
why the persistence of helminth eggs is a criterion taken into account in the law of
1998 on the approval of sewage sludge as fertilizer. The transmission of worms is the
consequence of sludge spreading on plots intended for pig, sheep, or cattle breeding.
Ascariasis is a parasitic infection caused by the nematode worm Ascaris parasitizing
the small intestine of mammals. Ascaris lumbricoides is found in sewage sludge, and
its eggs contaminate the soil and plants after sludge spreading, resulting in the
infection of any organism that consumes them [1]. A. lumbricoides is the largest
intestinal roundworm and is the most common helminth infection of humans worldwide. Infestation can cause morbidity by compromising human nutritional status
[57] or affecting cognitive processes [58] inducing tissue reactions such as granuloma to larval stages and causing intestinal obstruction, which can be fatal. This
worm weakens its host by eating the ingested nutrients. Knowing that this worm is
particularly virulent in the tropics, it causes problems of undernutrition in countries
having trouble feeding. Thus, it decreases the hosts’ immune defenses making them
vulnerable to other diseases. In endemic areas, massive infections (200 to 1,000
worms) cause serious damage including intestinal obstruction that can lead to death.
The worms in abundance eventually cross the intestinal wall to spread throughout
the body and cause multiple problems (irritation, lesions, and edema). Hookworms
Ancylostoma duodenale and Necator americanus are two nematodes parasitizing
mammalian duodenum and jejunum. As with most parasitic nematode worms, they
cause skin lesions, respiratory irritation and lack of nutrition with inflammation of
the intestine. However, hookworms differ from other intestinal helminthiases in
attacking male adults rather than children. Giardiasis is also an intestinal disease,
including diarrhea, caused by Giardia intestinalis, a flagellated protozoan [59]. This
parasite can form cysts that are particularly resistant to WW treatment. It can be
transmitted to humans by non-potable water or by ingestion of contaminated food. In
the case of sewage sludge, it can be transferred to livestock after soil sludge
application. Giardia is asymptomatic most of the time. However, it can cause
diarrhea from a certain concentration of parasites. These diarrheas can become
serious when the protozoan is present at high quantity. A recent study by Amorós
et al. [60] in raw and treated sewage sludge showed that Cryptosporidium oocysts
and Giardia cysts were present in 26 of the 30 samples (86.6%) of raw sludge
Environmental, Economic, and Ethical Assessment of the Treated Wastewater and. . .
63