Mollusks can act as intermediate hosts to various species of trematode (fluke), nematode (roundworm), and cestode (tapeworm), which are then transmitted to hosts that can include wildlife, cattle, domestic animals, and humans. Because of the pathogens and parasites that most snails and slugs can transmit, personnel should wear gloves when handling any specimens.

Plant pathogen spores have been found in snails and slugs, but the role gastropods play in transmitting these plant pathogens remains generally unknown.

Refer to taxon-specific datasheets for details about terrestrial snails and slugs of interest.

Look for snails or slugs of interest (see datasheets for images and descriptions) and physical signs of snail or slug presence such as feeding damage on plants and mucus, slime trails, or ribbon-like feces on and around hosts. 

Surveys should take place when snail and slug populations are most likely to be apparent. The mollusk groups targeted for early detection surveys are highly variable, and surveyors must consult species-specific datasheets for details. 

Survey in areas immediately surrounding ports of entry, rail yards, airports, container yards, and cargo distribution areas. Perform a comprehensive survey by visually searching for slugs and snails in appropriate microhabitats, following the guidance below.

For all species:

• Shipping containers and container storage areas
• Vehicles, including tires, and heavy equipment, including railroad tracks
• Parking areas/lots, specifically targeting areas with vegetation 
• Areas with vegetation, especially areas where plants exhibit feeding damage
• Under rocks, cement, and asphalt pieces that are in loose contact with the soil
• Discarded wooden boards, fallen trees, logs, and branches
• Compost piles, rubbish heaps, and damp (not wet/soggy) leaf litter, which may be necessary to sort through
• Under flowerpots, planters, and on/among vegetation that can hold water (e.g., bromeliads, lilies)
• Under boards, old carpets, rubber mats, tires, and other items in contact with the soil
• Behind air conditioning units, under porches, corners of buildings, and other cool, damp places near homes or buildings
• Other areas indicated in species-specific datasheets

Additional areas of concern for dry-tolerant species (i.e., some Cochlicella spp., Monacha spp., Theba pisana)

• Look off the ground on plants, on structures 
• Standing rock walls, cement pilings, and etc.

Visual Survey

• To ensure coverage of the whole survey area, consider laying grids or transect lines across the site and then choosing microhabitats within the grids or along the transects most likely to harbor mollusks.
• If objects are safely moveable (e.g., small rocks or logs), lift them and examine both the object and the soil underneath for snails. Brush or lightly dig the top layer of soil to look for mollusks. Replace soil and the objects in the same position where they were found.
• Examine structures that are elevated off the ground (3 feet or more in height), particularly if surveying when mollusks are likely to be active. Note that these snails and slugs are mostly terrestrial, but some have the potential to be arboreal and on elevated structures and vegetation. See datasheets for species of interest.
• If the target survey area shares edges, survey the margins that meet the survey area, where mollusks may be more common (Koz?owski, 2010).
• Use flashlights and check the undersides of objects or structures for mollusks or slime trails.
• Do not survey in non-habitat areas contained within the survey site (e.g., in bodies of water, in paved areas).

Trapping

Trapping can be used to supplement visual surveying in high-risk sites. Platform traps (baited or unbaited) act as artificial daytime refuges that attract snails and slugs for easier collection.

Place cardboard or wood sheets either directly on the ground or elevated one inch off the ground. These can be baited with fermenting bread dough or by painting the underside with a yeast suspension; both are very attractive to many snail and slug species (Schneppat and Heim, 2020; Veasey et al., 2021). Check underneath the sheets regularly for target gastropods.

1. WEAR GLOVES. Because of the pathogens and parasites that most snails and slugs can transmit, personnel should wear gloves when handling any specimens. If gloves are not available, use other tools to manipulate the mollusk do not handle the mollusk directly. Always immediately disinfect hands with hot, soapy water or hand sanitizer.
2. Screen samples prior to submission. Sort out debris and non-mollusk organisms. 
3. Collect snails and/or slugs in a jar/vial and euthanize them by covering with ethanol (80% or above) 
   • Note: It is recommended that you collect multiple specimens of the snail or slug if possible. Prioritize collecting and sending the largest specimens available.
4. After snails or slugs are fully covered in ethanol for at least a few hours, the ethanol can be drained and replaced with paper towel material inside the jar/vial. Add more ethanol to just soak the paper towel. Add another piece of loose paper towel (to prevent specimen movement during shipping).
   • Note: Mailing companies have regulations against large volumes of ethanol, so the ethanol-infused paper towel reduces the volume.
5. Place jar/vial in a double plastic bag (zip-lock or equivalent) and protect for mailing.
6. Label specimens with the date, exact location (GPS coordinates), and details on the substrate, microhabitat, or plant hosts on which the specimen was found.
7. Mail the jar(s)/vial(s) to the Malacology lab via UPS or FedEx at the following address:Attn: 

• Drs. Francisco Borrero and Morgan Bullis
  Malacology Identification Specialist
  USDA-APHIS-PPQ
  Academy of Natural Sciences
  1900 Benjamin Franklin Parkway
  Philadelphia, PA 19103-1101
  Phone: 215-847-3271 

      8. It is recommended that you email PPQNISNTMalacology@usda.gov to let them know that a sample is on the way and that you liaise with the appropriate USDA-APHIS-PPQ officer in your state/region to ensure that any specimens submitted for identification by NIS are accompanied by the required Agricultural Risk Management (ARM) System form. If assistance is needed to find the appropriate officer in your region, please contact PPQNISNTMalacology@usda.gov.

This will vary based on the species. Please see taxon-specific datasheets.