Haff Disease

Haff disease is a rare seafood-related illness that affects about one person in the United States each year. There have been three reported incidents of Haff disease in Illinois, with the last case occurring in 2019. The two prior incidents occurred in 2004 and 2014. All Illinois cases of Haff disease were related to consumption of buffalo fish.

Haff disease is a syndrome of unexplained rhabdomyolysis occurring within 24 hours of fish consumption. It is suspected of being caused by an unidentified toxin. Rhabdomyolysis occurs when damaged muscle tissue releases its protein and electrolytes into the blood. Rhabdomyolysis is a serious medical condition that can cause kidney damage, dangerous heart rhythms, seizures, nausea and vomiting, permanent disability, and death.

In the United States, Haff disease has been linked to the consumption of buffalo fish, crawfish, and salmon. In Illinois, the three observed cases have involved buffalo fish, which are commercially harvested from large rivers and reservoirs. Three species of buffalo fish occur in Illinois (bigmouth, smallmouth, and black buffalo), though it is unknown which species have been associated with the cases of Haff disease due to the species’ physical similarities and overlapping habitats.

Common symptoms associated with Haff disease include extreme muscle stiffness, muscle pain, chest pain, difficulty breathing, numbness, loss of strength throughout the body, and dark brown urine. Severe symptoms typically resolve within two to three days, though prolonged muscle weakness may remain. Complications of Haff disease include acute kidney failure and abnormal blood clotting. The case fatality rate of Haff disease is about 1%.

Other than limiting your consumption of seafood, there are no known measures to lower your risk for Haff disease. You cannot tell if a fish contains the toxin based on its taste, smell, or appearance, and the toxin cannot be destroyed by cooking. It is unknown if the disease is caused by improper packaging or storage of fish or if it is attributed to the fish’s environment. Since the majority of incidents in the United States have involved buffalo fish, those who frequently consume buffalo fish should monitor themselves for the symptoms of Haff disease.

Seek medical attention immediately if you’ve recently consumed seafood and are exhibiting symptoms of Haff disease. After you have received medical attention, notify your local health department to document the illness and prevent others from becoming inflicted. If leftover fish is available from the meal, do not throw it out. IDPH or partner agencies may request a fish sample for testing.