A parasitic worm that causes serious infections, especially via foods and beverages, has sickened at least three mainland visitors to Hawaii’s Big Island, according to state officials.

Hawaii’s health department director has released information provided to the state by the federal Centers for Disease Control and Prevention about the confirmation of the infected patients. Hawaii Gov. David Y. Ige joined Health Director Bruce Anderson in the announcement, which did not indcate when the federal agency contacted them. Cases of rat lungworm infections have received increasing coverage from news media across the country in recent years.

Specific tests are required to diagnose rat lungworm infections, which come from microscopic creatures that infect rats. Larvae infect the rats’ lungs and are then passed through their feces to animals that people eat, such as snails and frogs. The parasitic worms travel through the human body to the brain and can cause eosinophilic meningitis and/or damage the central nervous system.

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“People also can get infected by accident, by eating raw produce such as lettuce that contains a small snail or slug or part of one,” according to the CDC. 

Certain animals such freshwater shrimp, crabs, or frogs, have been found to be infected with larvae of the parasite and can therefore infect people, according to CDC information. Eating undercooked or raw animals that are infected can result in people becoming infected. Fish do not spread this parasite. 

Some people become infected from drinking rain water collected from roofs and other untreated sources that are accessible to carrier animals, according to health care officials who have spoken to Food Safety News in recent years. Many homes in Hawaii are not connected to municipal water sources. Carrier animals can also contaminate traditional regional dishes that are often cooked outdoors. 

Children and other people who drink from garden hoses have also been infected, according to reports in the U.S. and Europe.

Transmission routes for recently confirmed patients
Two of the patients recently confirmed by CDC laboratory analysis became ill early this year. The third visited Hawaii in December 2018 and became ill later that month. All three visited Hawaii Island, also known as the Big Island, before becoming sick.

The person who became ill in December visited East Hawaii “and became infected by purposely eating a slug on a dare” according to the health director’s announcement. Statewide, 10 people were confirmed to have been infected with angiostrongyliasis, the scientific name for rat lungworm disease, in 2018. 

Some researchers and government officials in Hawaii say the disease is under-reported and often not diagnosed. Specific testing is necessary and many health care providers are not aware of the symptom set the disease causes and therefore do not order the appropriate tests.

The two people who became ill from the parasite in January and the December 2018 patient, were infected in unrelated scenarios. The January cases had traveled to the opposite side of Hawaii Island that did the patient from December 2018.

One of the people who became ill in early January recalls eating many homemade salads while on vacation on the Big Island. The state’s investigation could not determine for sure how the individual was infected, according to the health department statement. 

“The other individual became ill in late February and was hospitalized for a short time. The investigation was not able to identify an exact source of infection, but the individual likely became infected while ‘grazing,’ or eating unwashed raw fruits, vegetables and other plants straight from the land,” according to state health officials.

With the confirmation of the two patients, the state has logged five confirmed cases of angiostrongyliasis in 2019.

Action taken by state officials
To help minimize the number of people who become infected, the state has posted information on signs “in local airports and shopping centers.”

“It’s important that we ensure our visitors know the precautions to take to prevent rat lungworm disease, which can have severe long-term effects,” said Anderson in this week’s announcement. “Getting information to visitors about the disease is just as critical as raising awareness amongst our residents.”

The Hawaii Department of Health has posted tips for avoiding the parasitic disease, including:

  • Wash all fruits and vegetables under clean, running water to remove any tiny slugs or snails. Pay close attention to leafy greens.
  • Control snail, slug, and rat populations around homes, gardens and farms. Get rid of these vectors safely by clearing debris where they might live, and also using traps and baits. Always wear gloves for safety when working outdoors.
  • Inspect, wash and store produce in sealed containers, regardless of whether it came from a local retailer, farmer’s market, or backyard garden.

In recent years victims have reported being infected after eating only in restaurants. Some have said they discovered snails or parts of snails in restaurant salads. Some have reported eating traditional dishes prepared outdoors, according to researchers and health care professionals in Hawaii.

To read previous Food Safety News coverage about rat lungworm disease, please see:

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