Distribution

Fresh and sea water. Cases of poisoning seen predominantly in Europe, Asia and North America.

Biology

In ichthyootoxic fish, it is the reproductive organs and their products that are poisonous. The consumption of roe (fish eggs) is particularly dangerous. The presence of toxins appears to correlate with the reproductive season.

Ichthyootoxic fish belong to families that vary greatly taxonomically, and nothing is known about the nature of the toxins. Although toxic phospholipids have been found in the roe of individual fish, it is still not certain whether the toxins are produced by the fish themselves or are ingested by the fish via the food chain.

Risk

The toxicity of many species that are associated with ichthyootoxicity is doubtful and is often based on descriptions from around the beginning of the 20th century or earlier. The most dangerous representatives, which are believed to be the cause of many cases of poisoning in Europe and Asia, are minnows of the genus Barbus (Barbels), Tinca (Tenches) and Schizothorax (Marinkas), as well as Stichaeus from the Stichaeidae family. There are believed to have been fatalities due to the consumption of Schizothorax and Stichaeus roe. Although cooking is said to destroy most ichthyootoxins, this might not be completely safe, since the poison in some fish roe seems to be resistant to heat.

Signs and symptoms

According to Halstead (2001a), the following signs and symptoms commence shortly after the consumption of roe (cause not mentioned):

abdominal pain, nausea, vomiting, diarrhoea, headache, fever, bitter taste in the mouth, dryness of the mouth, intense thirst, a sensation of constriction of the chest, cold sweats, irregular pulse, low blood pressure, cyanosis, pupil dilation, syncope, chills, dysphagia and tinnitus. In severe cases there may be muscle cramps, paralysis, coma and even death.

Treatment

Symptomatic.

Literature (biological)

Halstead 1988, 2001a, Burns 1988