Apple snails creep into local waterways; can bring illness

Louisiana has seen an invasion.
Apple snails, native to South America, are in our local waterways, causing agricultural and ecological damage.
“The problem [with apple snails] as with any invasive species, [they] will overpopulate and steal resources away from native species, disrupting natural ecological processes,” according to the Barataria-Terrebonne National Estuary Program at Nicholls State University. “They consume large quantities of plant material, damaging important habitat for native fish and wildlife.”
Apple snails were first found in Louisiana back in 2006. A drainage canal in the back of a subdivision in Gretna was the first location reported, but they have since been found in multiple waterways, including Bayou Teche.
According to Susan Williams, whose home is located on the Teche in Calumet, the snails can be seen all over in the waterway. Williams said children are playing with them, not realizing they are a threat that needs to be eradicated.
The snails are golden-yellow to dark brown in color and their shells are heavy. They can grow up to six inches across, but are more frequently seen in the two to four inches range.
The most visible sign of the invasion are the snail’s eggs. The eggs are bright pink and are laid in clumps of 200-600 tiny eggs attached to a tree stump, piling or any other object just above the waterline.
Multiple residents have reported seeing the bright pink clusters in the marshes, in Lake Palourde, in the Spillway, and many bayous and other waterways.
Apple snails also pose a threat to human health. According to the Barataria-Terrebonne National Estuary Program, “If eaten raw, they can transmit a deadly parasite called rat lungworm to humans and other mammals.”
If the snail is infected with the roundworm parasite named Angiostrongylus cantonensis and is ingested raw by a human or other mammal, they can become infected.
Rat lungworm disease affects the brain and spinal cord and symptoms can include severe headache, stiffness of the neck, tingling or painful feelings in the skin or extremities, low-grade fever, nausea, and vomiting. Sometimes symptoms can be severe, causing a temporary paralysis of the face as well as light sensitivity.
Unfortunately, there is no pesticide to selectively eliminate the snails. The only way to combat them is to hand remove the bright pink egg masses, effectively reducing their numbers. Egg masses can simply be scraped off the structures and allowed to fall into the water where they become inundated with water and become infertile.
There is no risk of illness from touching the egg masses or the shells, but it is suggested to wear gloves or other protective equipment if the eggs are scraped off.
The Louisiana Department of Wildlife and Fisheries is asking for the public’s help in combating these intruders. If apple snails or their eggs are seen, they are asking that the location be noted and reported to: Bobby Reed, Aquatic Nuisance Species Coordinator, 225-765-3977 or email at breed@wlf.la.gov.