The uninterrupted occurrence of diphyllobothriasis nihonkaiense in urban areas implies that the D. nihonkaiense tapeworm perpetuates its natural life cycle successfully between salmon and its final host animals in northern territories of the Pacific Ocean; however, its definite natural life cycle remains to be elucidated.
The natural life history and the geographic range of the tapeworm remain to be elucidated, but recent studies have indicated that the brown bear in the northern territories of the Pacific coast region is its natural final host.
Recent molecular studies of the DNA sequences of the 18S rDNA, internal transcribed region 1, cox1, and nad3, clearly indicated the synonymy of D. klebanovskii to D. nihonkaiense, indicating that D. nihonkaiense is distributed not only in Japan but also in Far East Russia up to the Kamchatka Peninsula and that brown bears are its natural final host (21 ).
However, each Anisakis species has a specific distribution area and host range, depending on the availabilities of its intermediate and final hosts.
"Saturday Night Live" announced its final four hosts for Season 42 on Thursday, and there's one in particular who stands out.
A Toxoplasma parasite, for example, can make an infected rat unafraid of cat odors, making it easier to get to its final feline host.
Bryan, University of Saskatoon, unpublished data] has shown that wolves in areas and periods of greater salmon consumption have higher prevalence of eggs from Dyphyllobothrium spp. This fish tapeworm uses piscivorous terrestrial mammals as final hosts in its life-cycle, which crosses the marine-terrestrial boundary.
A similar scenario could be played out this year, with Belgium, the Davis Cup final hosts, expected to choose an indoor clay court.
Parasite eggs are transmitted to intermediate hosts via carnivore faeces, whose distribution in the environment is driven by the defecating behaviour of final hosts.
It might be attributed to the altitude-dependent species richness and abundance of the intermediate and final hosts of the parasite.
