Introduction
Fish are considered a primary source of nutrition for humans, characterized by their high nutritional value. However, consuming them raw or undercooked may lead to the transmission of certain parasites to humans. This article reviews the most important parasites associated with fish, their transmission routes, health risks, and preventive measures.
Major Parasites Associated with Fish
There are three main groups of parasites that may be transmitted through fish:
Nematodes (roundworms): such as Anisakis spp. and Pseudoterranova decipiens. Their larvae are transmitted to humans when consuming raw or undercooked fish, causing anisakiasis with symptoms such as abdominal pain and nausea.
Cestodes (tapeworms): mainly Diphyllobothrium latum (the fish tapeworm). It develops in the human intestine as the definitive host and may cause vitamin B12 deficiency and severe anemia if left untreated.
Trematodes (flukes): such as Haplorchis pumilio and Centrocestus formosanus. These are transmitted through freshwater fish and cause gastrointestinal disorders of varying severity.
Mechanisms of Transmission
These parasites are usually transmitted through their larval stages present in fish flesh or viscera. Eating raw, salted, or inadequately smoked fish increases the risk of infection. Some parasites, such as Anisakis, do not complete their life cycle in humans but still cause acute symptoms, while others, such as Diphyllobothrium latum, can develop and adapt inside the human body.
Health Risks to Humans
Severe gastrointestinal symptoms (nausea, abdominal pain, diarrhea).
Vitamin B12 deficiency and anemia (particularly in fish tapeworm infection).
Gastrointestinal irritation and allergic reactions (especially in anisakiasis).
Rare but serious infections may occur when consuming fish contaminated with certain trematodes in endemic regions.
Prevention and Control
To reduce the risk of fish-borne parasitic infections, the following measures are recommended:
Proper cooking of fish to a core temperature of ≥63°C to kill most parasites.
Adequate freezing of raw fish at −20°C for 7 days or −35°C for 15 hours.
Prompt removal of viscera after catching and storing fish at low temperatures.
Raising awareness about safe preparation methods, especially for raw or semi-raw dishes.
Strict health inspection of fish in markets and restaurants.
Conclusion
Certain fish parasites can be transmitted to humans, causing gastrointestinal diseases or nutritional deficiencies. Nevertheless, adherence to proper cooking and storage practices makes fish consumption largely safe. Understanding these parasites, their transmission, and prevention methods is essential for protecting public health, especially with the global rise in popularity of raw seafood dishes.
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