Rat Lung Worm in the Garden

Glenn I. Teves, UH CTAHR County Extension Agent

Recently in Hana, Maui, there have been cases of Rat Lung Worm, a microscopic nematode that causes a neurological disorder in humans called Eosinophilic Meningitis. This disorder affects people differently, from a headache to severe paralysis and even death. The Rat Lung Worm has a complex life cycle requiring growth stages both in a rat and a slug in order to develop the stage that infects humans.
In most instances, this disease has been spread by slugs in fresh produce eaten raw, and grown in the area, especially in home gardens. The Rat Lung Worm lives in the lungs of rats and is shed in its feces. Slugs usually pick up the Rat Lung Worm by consuming or coming in contact with rat feces.
There many ways to prevent this disease from coming in contact with your food. Controlling and keeping slugs and snails away from your garden vegetables eaten raw, including lettuce, mustards, spinach, and others, is the key. Cooking vegetables will kill the rat lung worm. Washing all produce outdoors with clean water is important to prevent cross-contamination in the kitchen. Properly washing and rinsing before eating cannot be overemphasized.
Slugs and snails are nocturnal and are in higher populations and more mobile in the wetter areas of the island. In drier areas, they will start to migrate at the first rain and move on moist nights. Checking gardens at night in wet or moist weather and physically removing them can help to keep populations low. Do not handle or touch them, and neoprene gloves are recommended as added protection. Placing boards, such as foot squares of plywood on the ground near the garden will create houses for them and is a good way to monitor and remove them from the area. Baits can be used under boards to assure that non-target organisms such as birds, dogs, and cats are not harmed.
Baits used to control slugs and snails include active ingredients Sulfur, Copper, Iron Phosphate, Methiocarb, and Methaldehyde. Some baits are organic and may not kill slugs on contact. As with all pesticides, please read and follow the label. We may be living in paradise, but it’s also paradise for diseases and other organisms.
For more information on the Rat Lung Worm, you can download the following free publications from the University of Hawaii College of Tropical Agriculture and Human Resources website:
CTAHR Farm Food Safety, Good Agricultural Practices:
manoa.hawaii.edu/ctahr/farmfoodsafety/rat-lungworm/

Best On-Farm Food Safety Practices: ctahr.hawaii.edu/oc/freepubs/pdf/FST-39.pdf
Student and Food Safety: Best Practices for Hawaii School Gardens: ctahr.hawaii.edu/oc/freepubs/pdf/FST-45.pdf
Wash Fresh Fruits and Vegetables Before Eating:
ctahr.hawaii.edu/oc/freepubs/pdf/FST-35.pdf