The fish tapeworm occurs worldwide (Europe, northern Siberia, North America, western Africa, South-East Asia, Japan, Australia)
Humans become infected by eating raw or undercooked fish (e.g. pike, perch, salmon)
Besides humans, as an important final host, wild and domestic carnivore animals serve as reservoir hosts
Pathology – provoked in most cases by a single worm – is light
Hosts might be depleted of vitamin B12, resulting in rare cases in a macrocytic anaemia (especially in Scandinavia)
Proglottids of Diphyllobothrium latum.
The species characteristics are: the proglottid is broader than it is long; size 2 to 4 mm long by 10 to 12 mm wide; uterus coiled in rosette appearance; genital pore at the center of the proglottid.