Relationship between the prevalence of Dibothriocephalus latus (Cestoda: Diphyllobothriidea) and the load of Escherichia coli: New findings in a neglected fish‐borne parasitic zoonosis

Abstract

Humans contract a variety of parasitic fish-borne zoonoses, many of which are caused by helminths such as cestodes, trematodes and nematodes (Chai et al., 2005). Infections occur through the consumption of raw, undercooked or improperly processed fish products (salted or marinated fish fillets) harbouring viable larval stages of zoonotic parasites (EFSA, 2010). The type and the number of parasites in fish products depend on the environment where the fish was farmed or fished (Iwamoto et al., 2010). The large sub-Alpine lakes of Switzerland, Italy and France have long been reported an endemic area of diphyllobothriosis, a parasitic zoonosis caused by Dibothriocephalus latus (previously named Diphyllobothrium latum).According to recently published data, an estimated 20 million people are infected worldwide; however, the global prevalence of D. latus is unknown (Scholz et al., 2009). A recent survey funded by the Italian

Unique genetic structure of the human tapeworm Dibothriocephalus latus from the Alpine lakes region – a successful adaptation?

“…The probability of errors during meiosis and mitosis can increase under severe environmental conditions (Lorch et al , 2016). The subalpine lakes belong to anthropized water systems affected by intensive industrial, agricultural and urban activities (Lang, 1989; Anneville et al , 2007; Manca et al , 2007; Menconi et al , 2021). It could contribute to spontaneous polyploidization and aneuploidy and to changes in reproductive strategy, which are common in harsh environments and bottlenecked populations (Lorch et al , 2016).…”

“…The other 5 subalpine lakes were chosen as study areas due to their similar ecological conditions. The Italian lakes Iseo, Como and Maggiore were originally oligotrophic but underwent severe cultural eutrophication caused by urban, industrial and/or agricultural pollution (Manca et al , 2007; Menconi et al , 2021). Lakes Geneva, Biel and Neuchâtel in Switzerland suffered from eutrophication but later became mainly mesotrophic (Lang, 1989; Anneville et al , 2007).…”

“…Diphyllobothriosis has persisted in ALR despite great efforts to eliminate the further spread of the disease, mainly due to eating habits and the proliferation of restaurants serving raw fish, insufficient disinfection of wastewater and the many yachters and fishermen using the lakes (Dupouy-Camet and Peduzzi, 2004;Jackson et al, 2007). Since 2000, diphyllobothriosis has been diagnosed in human patients from Switzerland, Italy and France and D. latus has also been frequently detected in fish from various subalpine lakes (Wicht et al, 2010a(Wicht et al, , 2010bDupouy-Camet et al, 2015;Menconi et al 2020Menconi et al , 2021.…”

The Occurrence of Freshwater Fish-Borne Zoonotic Helminths in Italy and Neighbouring Countries: A Systematic Review

“…Although a few isolated cases were noted later on, diphyllobothriasis was generally considered a minor public health concern [82][83][84]. However, in the last 20 years, a rising number of human diphyllobothriasis cases was observed in Italy, France, and Switzerland [85][86][87]. In fact, the endemic area of this parasite mainly concerns the great alpine lakes of these three countries [86,[88][89][90][91][92][93].…”

“…The D. latus life cycle involves two intermediate hosts, a crustacean copepod (Cyclops) and a predatory freshwater fish (P. fluviatilis), and one definitive host, a fish-eating mammal (including humans) [87] (Figure 3). The parasites can also be transmitted to other paratenic hosts such as burbot (Lota lota), and pike (Esox sp.…”