Field Guide to Venomous and Medically Important Invertebrates ...

Symptoms generally include pain, swelling, redness and itching that may last several days.
Small lesions may appearr at the bite location. Recovery is otherwise uneventful.
Figure 260. Polychete worm (Glycera sp.). Photo: David Remsen.
Figure 261. Mouthparts of the polychete worm Glycera sp. Photo: source unknown.
Mollusks
There are over 70,000 described species in the Phylum Mollusca that are distributed worldwide
in terrestrial and aquatic habitats. However, only a few species can cause injury and potential
death to people through envenomation or as a host of certain parasites. All of these mollusks are
aquatic and occur in marine or freshwater habitats.
Several members of the Class Cephalapoda (squids, octopuses, cuttlefishes) are capable of
inflicting painful and potentially dangerous bites with their hardened tooth-like beaks. The
salivary glands associated with the beaks are used to kill or immobilize prey items, and they will
inflict painful bites to people when threatened or handled. Symptoms stemming from
envenomation include pain, stinging and burning sensations and swelling related to the original
bite, as well as nausea, vomiting, diarrhea, fever, headache, and chills. Some victims have
reported blurred vision, difficulty talking, and loss of feeling in the extremities. Other victims
may develop convulsions, respiratory distress, and paralysis. Death can occur, but mortality
rates attributed to cephalopods is generally less than one percent. Recovery normally is
complete within 2 days. Cephalopods occur exclusively in marine habitats but they are
distributed in oceans worldwide. The blue-ringed octopus (Octopus maculosus) of Australia has