According to the World Register of Marine Species database, there are 10,762 accepted cnidarian species and about 100 of these are considered harmful to humans. Cnidarian envenomations are common all around the world. This chapter is a collection of unusual cnidarian envenomations. A correct diagnosis and appropriate treatment are essential in cases of cnidarian envenomations, particularly because specific antivenoms are lacking. Reactions to fire corals are also very severe. Physaliae stings are usually painful and severe, and go together with systemic manifestations that can involve various organs.
#Anemona actinia skin
True corals provoke skin lesions through toxic and traumatic mechanisms. Sea anemones can cause cutaneous and systemic manifestations, including seabather’s eruption, characterized by pruriginous papulous lesions that persist for 1–4 weeks. Box jellyfish are among the most significant toxic marine animals, and their envenomation usually presents as a medical emergency. True jellyfish induce a great number of accidents in the world, although they are generally less severe than those caused by box jellyfish and physaliae. Different clinical pictures can arise after Cnidarians envenomations, featuring skin and systemic reactions that can even be fatal. Injuries caused by cnidarians are of two pathogenic orders, toxic (the most common mechanism) and allergic (of immediate or delayed type). An organ synthesized by the nematocytes, the nematocyst, is expelled in a harpoon-like fashion during a nanosecond process, and injects different active toxic substances into the prey.
Highly specialized cells (nematocytes) are present on the surface of Coelenterata, and associated with the venom discharged during stings. The phylum of Coelenterata (Cnidaria), animals that have a worldwide distribution, includes four toxic classes: Anthozoa (sea anemones, true hard and soft corals and sea pens), Scyphozoa (true jellyfish), Hydrozoa (physalia and fire corals: not true corals), and Cubozoa (box jellyfish). Many of these toxins will be useful pharmacological tools and some will hopefully prove to be valuable therapeutic leads. Recent developments in multiple 'omic' technologies, including genomics, transcriptomics and proteomics, coupled with advanced bioinformatics, have opened the way for large-scale discovery of novel sea anemone toxins from a range of species. One of the impediments to the exploitation of sea anemone toxins in the pharmaceutical industry has been the difficulty associated with their high-throughput discovery and isolation. An analogue of this peptide, ShK-186, which is now known as dalazatide, has successfully completed Phase 1 clinical trials and is about to enter Phase 2 trials for the treatment of autoimmune diseases. This is surprising given the success of some anemone peptides that have been tested, such as the potassium channel blocker from Stichodactyla helianthus known as ShK. Sea anemones have been understudied as a source of peptide and protein toxins, with relatively few examined as a source of new pharmacological tools or therapeutic leads.