General Impact
Achatina fulica is considered one of the worst snail pests in the tropics and subtropics. It consumes large volumes of native plants, modifies habitats and out-competes native snails (Moore 2005). Achatina fulica may also effect native ecosystems by altering the food chain by providing an alternative food source for predators (Mead 1961). This can have unfortunate consequences if the predator species is also invasive. For example, in the Bonin Islands, Japan, the introduced invasive toad (Bufo marinus) was found to prey predominantly on Achatina fulica (Matsumoto et al. 1984). However, natural predation may alternatively help keep populations of Achatina fulica in check. For example, on the Christmas Islands Achatina fulica has not established in undisturbed rainforests; this is thought to be due to native red crabs consuming significant numbers of the snail (Lake and O'Dowd 1991).
Achatina fulica is a major agricultural pest, feeding on a variety of crops and causing significant economic losses. In the US state of Florida it has been estimated that Achatina fulica would have caused an annual loss of $US11 million in 1969 if its population had not been controlled (USDA 1982). In India it attained serious pest status, particularly in 1946/47, when it appeared in epidemic proportions in Orissa and caused severe damage to vegetable crops and rice paddies (Pallewatta, Reaser and Gutierrez 2002). Plants most likely damaged by the snail are garden flowers and ornamentals, vegetables, (especially Cruciferae, Cucurbitaceae and Leguminosae) and immature specimens of breadfruit, cassava and teakwood. Achatina fulica may also increase the spread of plant diseases (for example, black pod disease caused by Phytophthora palmivora), which it spreads in its faeces. (Mead 1961; Muniappan et al. 1986).
The introduction of Achatina fulica has often lead to the purposeful introduction of predatory snails and flatworms as biological control agents. These agents usually have a devastating effect on the environment. For example, a particularly important cause of the demise of the endemic snails in forested habitats in Tahiti and Hawaii has been the deliberate introduction of the predatory snail (Euglandina rosea and predatory flatworms, such as Platydemus manokwari to control Achatina fulica. However, reports that this flatworm can control Achatina fulica remain correlative and are based on an insufficient understanding of ecological principles (Muniappan 1990).
Achatina fulica is a vector for several pathogens and parasites, including the roundworm responsible for eosinophilic meningo-encephalitis in humans (News from MAF 2005) and the bacterium Aeromonas hyfrophila (also found in shellfish in New Zealand) (Kliks and Palumbo 1992). The parasites carried by the snail are usually passed to humans through the consumption of raw or improperly cooked snails (Moore 2005). For example, in American Samoa 16 Korean fishermen contracted eosinophilic radiculomyeloencephalitis disease following eating a meal of Achatina fulica infected with the parasite Angiostrongylus cantonensis (Kliks et al. 1982).
Achatina fulica are also a general nuisance when found near human habitations and can be hazardous to drivers, causing cars to skid. Their decaying bodies also release a bad stench and the calcium carbonate in their shells neutralises acid soils, altering soil properties and the types of plants that can grow in the soil (Mead 1961).
Location Specific Impacts:American Samoa 
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may lead to predation on non-target species. Brazil
Ecosystem change: The snail threatens wetland ecosystems in Pantanal. There is a serious problem with regards to Achatina fulica and another alien mollusc. At some locations (chapadas and planaltos) Achatina fulica is a problem, but Limnoperna fortunei (Bivalvia, Mytilidae), from Asia is considered an even bigger problem in the wetland areas (C. Callil, pers. comm.). Cote d`Ivoire (Ivory Coast)
Agricultural: Achatina fulica became regarded as a significant crop pest shortly after its introduction to Ghana and the Ivory Coast (Raut and Barker 2002, in Cooling 2005).
Competition French Polynesia (Polynésie Française)
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Ghana
Agricultural: Achatina fulica became regarded as a significant crop pest shortly after its introduction to Ghana and the Ivory Coast (Raut and Barker 2002, in Cooling 2005).
Competition: Achatina fulica entirely displaced a native snail in Ghana (Cooling 2005). Guam
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. India
Economic/Livelihoods: Infestations of Achatina fulica have caused sufficient damage to crops to render some vegetable growing unviable. Madagascar
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Malaysia
Human nuisance: Achatina fulica is considered a serious garden pest in Malaysia. Marshall Islands
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Mauritius
Human nuisance: Achatina fulica is considered a serious garden pest in this country. Micronesia, Federated States of (FSM)
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. New Caledonia (Nouvelle Calédonie)
Agricultural: Taro and sweet potato are eaten by Achatina fulica in New Caledonia (F. Brescia, pers. comm.).
Agricultural: The introduction of Achatina fulica is a special case, given the seriousness of its consequences on the food economy and public health, and the ecological imbalances it causes (from Gargominy et al. 1996).
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Ecosystem change: The introduction of Achatina fulica is a special case, given the seriousness of its consequences on the food economy and public health, and the ecological imbalances it causes (from Gargominy et al. 1996).
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Human nuisance: The introduction of Achatina fulica is a special case, given the seriousness of its consequences on the food economy and public health, and the ecological imbalances it causes (from Gargominy et al. 1996).
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. New Caledonia (Nouvelle Calédonie) 
Economic/Livelihoods: In New Caledonia the effects of the snail A. fulica are greater on the nursery industry than on the crop sector (J. Manaute, pers. comm., in Cooling 2005). New Zealand
Agricultural: Achatina fulica could impact horticulture, agriculture, forestry and home gardens in New Zealand. Of the more than 500 species of plants it feeds on, the following plants are found in New Zealand: bananas (Musa species), Asplenium species, Bougainvillea species, cabbage and cruciferae, cactus (Opuntia and Cereus species), Canna species, carrots, capsicums, members of Compositae, Tagetes species, Citrus species, members of cucurbitacea, Daphlia species, eucalyptus species, ferns, figs, hibiscus, Impatiens balsamina, jasmine, members of Leguminosae, lettuce, lilies, oleander, orchids, passionfruit species, potato, Rosa species, spinach, members of Solanaceae (egg plant, chillies and tomato), taro species, tabacco and yam (Mead 1961, Srivastava 1992, Raut and Barker 2002, Animal and Plant Health Inspection Service 2005, in Cooling 2005).
Economic/Livelihoods: New Zealand's horticultural exports increased from approximately $1 300 000 in 1997 to approximately $1 800 000 in 2000 (Statistics New Zealand 2004, in Cooling 2005) and this sector would be one of the most likely, along with the nursery industry to be affected.
Other: The snail has the potential to out-compete and displace native species, to alter the community composition, to modify the habitat and to introduce fungi and parasites into native ecosystems.
Reduction in native biodiversity: Achatina fulica is known to eat Asplenium, Phorium and Cordyline species of snails (Venette and Larson 2004, in Cooling 2005). There are 16 native Asplenium species in New Zealand (Dawson and Lucus 2000, in Cooling 2005).
Such an adaptable species as A. fulica is also likely to cause significant harm to native plants (Animal and Plant Inspection Service 2005, in Cooling 2005). Northern Mariana Islands
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Palau
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Papua New Guinea
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Samoa
Agricultural: In 1994 Achatina fulica threatened the production of basic food crops such as bananas and coconuts in Western Samoa. Damage to staple yam crops in the Samarai-Murua District were significant (Conservation International 2005, in Cooling 2005).
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Human nuisance: Large numbers may foul roads, sidewalks, etc. Singapore
Human nuisance: The snail is considered a serious garden pest in this country. Solomon Islands
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Taiwan
Agricultural: Achatina fulica has caused significant damage to vegetable crops and citrus in Taiwan.
Human nuisance: Achatina fulica is considered a serious garden pest in Taiwan. Thailand
Human nuisance: The snail is considered a serious garden pest in Thailand. Trinidad and Tobago
Agricultural: Onions, potatoes, sunflowers, eucalyptus, brassicas and lettuce are preferred by A. fulica (Government of Trinidad and Tobago 2005, in Cooling 2005). Lana`i (Lanai) Is. (United States (USA))
Competition: Is causing extinction of unique snails. Hawaii (United States (USA))
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Vanuatu
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species. Wallis and Futuna
Agricultural: Potentially feeds on a range of crops.
Competition: Possible competition with native snail species.
Disease transmission: Vector of Angiostrongylus cantonensis, the cause of eosinophyllic meningoencephalitis in humans.
Herbivory: Agricultural and garden pest - may impact native vegetation.
Human nuisance: Large numbers may foul roads, sidewalks, etc.
Predation: Introduction of putatative biocontrol agents may leads to predation on non-target species.
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