© GONZALO JARA/SHUTTERSTOCK
Anisakis worms in blue whiting fish.
according to a study
published in the journal
Global Change Biology.
The parasite, called
Anisakis or "herring worm" is found in several species of fish and squid. When people inadvertently eat the worm, it can attach to the intestinal wall and cause symptoms akin to food poisoning, such as nausea, vomiting and diarrhoea.
This disease, known as
anisakiasis or anisakidosis, often goes under the radar because people understandably mistake it for a bad case of food poisoning, says senior author Chelsea Wood from the University of Washington, US.
Usually, the worm dies after a few days in humans and the symptoms disappear, although some cases can cause more severe reactions, including acute stomach pain, and persevere for months.
In marine animals, the parasite reproduces and is expelled in their faeces, from where it can infect crustaceans, such as bottom-dwelling shrimp or copepods, which are then eaten by small fish and from there on up the food chain.
Recent upsurges in the disease from several regions including Japan, the US and Europe has led to it being labelled an emerging zoonosis; whether this due to better detection, increased raw fish consumption or more parasites is unclear.
To investigate, Wood and colleagues collated data from thousands of papers that have investigated the proliferation of this worm over time.
Comment: Dengue fever cases surge 200% in Mexico in 2019