Update on the Giant African Snail (GAS) in Miami-Dade
County, FL
18th Annual Southwest Florida Invasive Species
Workshop
Eduardo M. Varona
USDA APHIS PPQ
State Operations Support Officer
January 23, 2014
History (Global)
• 1800’s started the migration from East Africa
• Mid 1930’s Hawaii - established
• Late 1940’s first detections in United States - contained
• 1958 Arizona - contained
• 1966 North Miami – 10 year successful eradication
• 2004 U.S. pets stores and schools –contained
• 2011 Miami-Dade County – ongoing eradication
• Current world distribution in the Americas includes: some Caribbean islands, and countries such as Colombia, Brazil, Ecuador, and others.
Pathways into the US
• Internet/mail
• Ceremonial use
• Pets
• Cosmetics
• Cargo
• Smuggling
• Hitchhiking
• General and permit cargo – 35
• Passenger baggage and miscellaneous – 34
• Mail - 8
• Total entries -77
USDA database query entries for Achatinadea
(01/2003 to present)
Biology
Lissachatina fulica Bowdich
Biology
• GAS is a major plant pest that consumes more than 500 varieties of plants.
• GAS can harbor the rat lungworm nematode, which can cause a rare form of meningitis in humans and animals.
Biology
• GAS can grow up to 8 inches in length.
• Adult GAS typically lay up to 1,200 eggs annually…
• There is no known natural predator in Florida for GAS
• GAS are hermaphroditic
Biology
• In lab tests, self-fertilization by GAS was possible when optimal mating conditions were not present. F1 viable.
• In lab tests, paired GAS can produce up to 730 eggs/month with a 51% viability
• Largest # of eggs produced in one clutch, 1,082
• In lab tests, specimens (neonates) can survive up to 97 days without food.
Current Eradication Program Overview
• First find on September 9, 2011- resident report to FDACS
• Field efforts carried out primarily by FDACS employees (51)
with significant USDA funding through a cooperative
agreement ($6.5 million to present)
• 25 Cores identified positive in Miami-Dade County, Florida w/
636 positive properties
• Since the inception of the Program to date:
– 89,177 inspections
– 50,131 treatments
– 137,809 GAS specimens collected.
Survey Process
• Twice monthly site visit
• Remove small yard debris
• Manual collection snails
– # per property
– % mortality
– Age structure
• Egg mass
– # eggs
– % viable embryos
• Shell length
• Treat site with Metaldehyde
Other Trends
• Mean size of collected shell has decreased
• Possible sublethal effects due to
treatments
– Fecundity
– Egg viability
• New cores detected after October 2011
and presently are much smaller in area,
lower in number of positive properties, and
contain smaller snail populations
– Cores 1-12 - average ~ 46 positive properties/core
– Cores 12-25 - average ~ 5 positive properties/core Julio Rodriguez, FDACS 2011
• Better traps – preventing escape
• Better baits – durable, clean, low cost
• New treatment formulations
• Aggregation pheromones
• Detector dogs – snails in hiding
Detector dogs in training…
will be used to assist in finding GAS
where human limitations exist, providing an a
an additional tool in the eradication effort.
Other Tools
Rat Lungworm
• Confirmed in GAS
October 2012
• 7 positive core areas
– Further research to
explore distribution
within cores
– Increased sampling in
other cores
Lindo et al. 2002
• GAS are known
carriers of
Angiostrongylus
Cantonenss (Rat
Lung Worm), which
can produce a rare
form of eosinophilic
meningitis, for which
there is no known
cure.
Outreach
Has been vital in identifying new infested areas in Miami-Dade
County and garnering ongoing support for program control activities.
Efforts have included: press events, radio/tv spots, national and
international coverage, bus benches, billboards, newspaper adds,
movie theatre advertising, school events, pet amnesty day booths,
natural areas managers workshops, and many others…
Of 25 infested “core’’ areas a full 90% of them have been detected as
a result of residents calling in with leads of “I think I have GAS on my
property”
Impacts to:
Human Health
• Rat Lung Worm -
meningitis
• Organic growers
• Home gardens
Natural Environment
Agriculture
• 500 Crops
• High reproduction rate -
increased management costs
• Economic damage - trade
• Public nuisance in urban areas
Outreach messages…
• Home grown potted plants and yard equipment
• Ceremonial practices
• Illegal dumping of debris (organic and inorganic)
• Collectors/purposeful introduction
• A pet snail
• Vehicles
• Internet
• Cargo
Potential modes of movement into SW FL
What We Are
Doing
Using Metaldehyde-
based products
Mechanical Collection
Inspecting Landfills and
Transfer Stations
Regulating
Landscapers, Lawn
Maintenance and
Botanicas
Public Outreach
How You Can Help
• Don’t move home grown potted plant material and yard equipment from or near infested areas to SW FL
• Monitor areas in your community with strong connections to infested areas
• Monitor illegal dumpsites particularly if materials there are suspected from SE FL
• Spread the word in your community
• Call if you suspect you have GAS
FDACS-GALS Hotline
1-888-397-1517
Bill Torres, GALS Program
Director (FDACS)
Office: (305) 278-0340 [email protected]
Eduardo M. Varona
USDA APHIS PPQ
State Operations Support Officer
(305)278-4873 Office
(305) 986-4407 Cell
To learn more about GAS and other pests of
concern to USDA, our state, and your community
go to USDA’s….
http://www.hungrypests.com/
Circle of Life?
Questions?
