Harmful to humans Mollusca

1 harmful humans

1.1 stings , bites
1.2 disease vectors
1.3 pests

harmful humans
stings , bites

the blue-ringed octopus s rings warning signal; octopus alarmed, , bite can kill.

some molluscs sting or bite, deaths mollusc venoms total less 10% of jellyfish stings.

all octopuses venomous, few species pose significant threat humans. blue-ringed octopuses in genus hapalochlaena, live around australia , new guinea, bite humans if severely provoked, venom kills 25% of human victims. tropical species, octopus apollyon, causes severe inflammation can last on month if treated correctly, , bite of octopus rubescens can cause necrosis lasts longer 1 month if untreated, , headaches , weakness persisting week if treated.

live cone snails can dangerous shell collectors, useful neurology researchers.

all species of cone snails venomous , can sting painfully when handled, although many species small pose of risk humans, , few fatalities have been reliably reported. venom complex mixture of toxins, fast-acting , others slower deadlier. effects of individual cone-shell toxins on victims nervous systems precise useful tools research in neurology, , small size of molecules makes easy synthesize them.

disease vectors

skin vesicles created penetration of schistosoma. (source: cdc)

schistosomiasis (also known bilharzia, bilharziosis or snail fever), disease caused fluke worm schistosoma, second malaria devastating parasitic disease in tropical countries. estimated 200 million people in 74 countries infected disease – 100 million in africa alone. parasite has 13 known species, 2 of infect humans. parasite not mollusc, species have freshwater snails intermediate hosts.

pests

some species of molluscs, particularly snails , slugs, can serious crop pests, , when introduced new environments, can unbalance local ecosystems. 1 such pest, giant african snail achatina fulica, has been introduced many parts of asia, many islands in indian ocean , pacific ocean. in 1990s, species reached west indies. attempts control introducing predatory snail euglandina rosea proved disastrous, predator ignored achatina fulica , went on extirpate several native snail species, instead.