Cystic echinococcosis in Iceland: a brief history and genetic analysis of a 46-year-old Echinococcus isolate collected prior to the eradication of this zoonotic disease.

Cystic echinococcosis (CE) is considered the most severe parasitic disease that ever affected the human population in Iceland. Before the start of eradication campaign in the 1860s, Iceland was a country with very high prevalence of human CE, with approximately every fifth person infected. Eradication of CE from Iceland by 1979 was a huge success story and served as a leading example for other countries on how to combat such a severe One Health problem. However, there is no genetic information on Echinococcus parasites before eradication. Here, we reveal the genetic identity for one of the last Echinococcus isolates in Iceland, obtained from a sheep 46 years ago (1977). We sequenced a large portion of the mitochondrial genome (8141 bp) and identified the isolate as Echinococcus granulosus sensu stricto genotype G1. As G1 is known to be highly infective genotype to humans, it may partly explain why such a large proportion of human population in Iceland was infected at a time . The study demonstrates that decades-old samples hold significant potential to uncover genetic identities of parasites in the past.

Moritella viscosa in lumpfish (Cyclopterus lumpus) and Atlantic salmon (Salmo salar).

Winter ulcer disease, caused by Moritella viscosa, is a significant problem in cold water salmonid farming, although the bacterium can infect and cause disease in a number of other fish species, such as lumpfish (Cyclopterus lumpus). Lumpfish are used as cleaner fish, to eat sea lice from Atlantic salmon (Salmo salar) in sea pens. It remains to be established whether M. viscosa can be transmitted between the fish species. In this study, we examined whether a salmon isolate of M. viscosa could infect and cause disease in lumpfish. We further examined whether a lumpfish isolate of M. viscosa could infect and cause disease in salmon. Finally, we examined whether vaccination of salmon with a salmon isolate of M. viscosa conferred protection against a lumpfish isolate. The data indicate that while lumpfish appeared to be resistant to a salmon isolate of M. viscosa, the salmon could be infected with a lumpfish isolate of M. viscosa. Vaccination protected the salmon against the salmon isolate of M. viscosa but did not confer sufficient protection to prevent infection with the lumpfish isolate.