We all realize that salmon is packed with healthy nutrients like protein and essential fatty acids. That’s why we love it. Something we don’t talk about much is this: Wild fish also can carry harmful parasites.

If your salmon isn’t prepared properly, it can pass these parasites on to you. Within hours of eating under-prepared salmon, the worms can burrow into a human’s digestive organs.

The good news: These worms can be killed through cooking or freezing the fish before eating it.

Clinical detail No. 1

The two likely types of parasites in salmon start as small larvae with big names: anisakis and diphyllobothrium latum. Both are rarely reported among Alaskans, but the full extent of illness is uncertain because the state does not require doctors or laboratories to report illnesses caused by these parasites, said Dr. Joe McLaughlin, a state epidemiologist.

Anisakis is a type of roundworm. Larva live in the guts of the fish and migrate to the muscle after the fish dies. When people eat the fish, the larva can penetrate their gastrointestinal tract. In some cases, abdominal cramping and vomiting can develop within hours of eating. Other symptoms can occur later, such as coughing that may bring up blood. Sometimes symptoms will mimic an appendicitis, McLaughlin said, citing a public health text.

Some people don’t require treatment, but others will need surgery or other medical procedures to remove the worm or lesions.

Clinical detail No. 2

Diphyllobothrium latum is a tapeworm. It’s also found in the muscle of the fish that people eat. Once inside the person, the larva can grow into a worm. Diphyllobothrium is the longest tapeworm hosted by humans — growing as long as 30 feet, according to a state health bulletin.

The tapeworm can be treated with a drug, but diagnosing the parasite can be difficult considering many people lack symptoms.

“Most people don’t even know they’re infected,” McLaughlin said. Possible symptoms can include anemia, abdominal cramping, diarrhea, even passing of worms, state health officials said.

Some say you can see these larva in the fish, while others call them microscopic. McLaughlin said you should treat all salmon the same, regardless of seeing parasites.

“The safest thing to do is assume it’s there,” said Ron Klein, food safety and sanitation program manager with the state Department of Environmental Conservation said. That means properly cooking or freezing the fish before eating.

How to avoid

Fish should be cooked long enough to reach an internal temperature of 145 degrees for at least 15 seconds, Klein said. People who smoke their fish to at least 150 degrees for 30 minutes also should kill the parasites, he said.

Another option is what some call “flash freezing” fish before serving it raw. That means freezing the fish to minus 4 degrees Fahrenheit or below for at least seven days, or freezing it to minus 31 degrees or below for 15 hours, Klein said. Like cooking, this freezing process kills the parasites. That type of freezing, however, may not be possible in freezers at home because they’re not kept at sufficiently low temperatures.

McLaughlin said another way to prevent parasites from traveling to the fish muscle is gutting the fish as soon as possible after catching it.

Brining and pickling the fish may lower the risk of parasites in the fish, but it doesn’t completely get rid of it, according to the U.S. Food and Drug Administration. In fact, a state health bulletin discusses a 1984 outbreak of diphyllobothrium latum in King Salmon that was linked to eating ceviche, or fish marinated in lime juice.

Dining out

The Department of Environmental Conservation currently doesn’t require restaurants and stores that sell fish for raw consumption to freeze it prior to sale. The department has proposed updating these regulations, however, and they are now open for public comment and could be approved by fall, Klein said. The new requirements would insist upon the freezing criteria mentioned above for stores and restaurants that sell ready-to-eat raw or partially cooked seafood other than mollusks or tuna.

In the meantime, McLaughlin said he recommends people ask stores or sushi restaurants the same question he poses: Do you freeze raw fish before serving it?

John Jackson, with the Sagaya Wholesale Division warehouse that stocks the New Sagaya markets, says salmon sold for grilling or cooking is typically fresh, although it may have been previously frozen. Almost all of the seafood used in the sushi has been previously frozen, with the exception of tuna, said Jackson, operations manager. He said he’s considering using flash-frozen tuna as well.

Peter Park, owner and sushi chef of Peter’s Sushi Spot in Anchorage, said he buys wild salmon and freezes it at the restaurant for seven days prior to using it for sushi.

Daily News reporter Ann Potempa can be reached at 257-4581 or apotempa@adn.com.