The number of helminths that are transmitted to humans from raw fish has grown 283 times over 40 years. This conclusion was made by scientists from the University of Washington, whose study was published in the journal Global Change Biology.
The study deals with herring worms – organisms that, despite their name, are found in various species of marine fish and squid. When a person eats raw or poorly cooked fish, parasites can enter the intestines.
Destroying the intestinal wall, herring worms cause nausea, vomiting and diarrhea. In most cases, the worm dies after a few days, and the symptoms disappear, and a disease called anisakiosis or anisakidosis is rarely diagnosed. Most doctors believe that a patient with these symptoms has experienced severe food poisoning.
This species of worms enters the body of fish when they eat small crustaceans – for example, bottom shrimp, as well as when predators eat smaller fish. Worms cannot breed or live in the human gut for more than a few days, but they can survive and breed in marine mammals.
Scientists conducted a study of changes in the number of herring worms in the body of fish – and came to the conclusion that from 1978 to 2015, their population grew by 283 times.
Although the health risks of these marine worms to humans are quite low, scientists believe that they can have a great impact on marine mammals such as dolphins, whales and seals. While biologists still do not know the physiological effects of these parasites on marine mammals, parasites can live in mammals for many years, which can have harmful consequences for them, the authors of the study conclude.