Palytoxin is one of the most powerful non-protein marine toxins so far well known, which was initially isolated from soft corals belonging to the genus Palythoa, to which the toxin owes its name. (Tartaglione et al., 2015).
Symptoms corresponding with palytoxin exposure differ profoundly depending upon the way of exposure. Mortalities have only happened because of palytoxin injection (in test animals) or ingestion (in humans),but a diversity of more non-lethal symptoms have been noticed due to ingestion, dermal, ocular, and inhalational exposure in humans. (Deeds et al., 2010). In common, the signs and symptoms comprise mostly the respiratory (rhinorrhea and coughing), gastrointestinal (nausea), skeletomuscular (myalgia, weakness, spasms), nervous (paresthesia, ataxia, tremors) system or apparatus and cardiovascular (electrocardiogram alterations) (Pelin et al., 2016).
Palytoxin is one of the most powerful coronary vasoconstrictors known, causing death within minutes by declining the oxygen supply to the myocardium (Vick et al., 1975). Studies of animals have shown that vasodilators, for example; papaverine and isosorbide dinitrate, can be utilized as antidotes.
Although, these antidotes are favorable only if injected into the heart directly after palytoxin exposure. In humans, the treatment is symptomatic and encouraging. Treatments such as gastric lavage, fluid administration, forced diuresis therapy, and artificial respiration is applied following oral administration, still, in some cases, mortalities cannot be averted.
To reduce the symptoms, the corticosteroids, nebulized β-agonists, NSAIDs, histamine antagonists, and oxygen therapy can be administered following inhalation or dermal exposure, with a recovery duration of a few hours to days (Patocka et al., 2018).
There is no particular therapy for or antidote to the poisoning of palytoxin and for this reason, treatment is encouraging (Snoeks & Veenstra, 2012). No antidote is available for palytoxin. Barely the symptoms can be weakened (Thakur & Jha, 2016). Animal studies have revealed that vasodilators, for example; papaverine and isosorbide dinitrate, can be used as antidotes.
Experiments on animal have only expressed benefit if the antidotes were injected into the heart immediately after the palytoxin exposure (Wiles et al., 1974).
Palytoxin in eye and rash
The entire pathophysiology of palytoxin causing injury to the eye remains unrevealed. The cornea may be specifically susceptible as Na/K+ pumps continue stromal deturgescence through the corneal endothelium acting versus sodium gradients, and this process dysregulation may assist to bulla formation and swelling of the cornea.
Appropriate tear film production depends immediately after the action of Na/ K+ against sodium gradients, and poor quality tear films may intensify corneal injury. Palytoxin disturbance of the system of actin filaments may also weaken the migration of endothelial and limbal stem cells during the corneal rebuild and explain the continued healing process (Cheung et al., 2017). The signs and symptoms of palytoxin poisoning by ocular exposure will be treated with artificial tears and corticosteroids (Pelin et al., 2017).
Unexpected cutaneous exposure to palytoxin-contaminated corals by aquarium hobbyists while cleaning marine aquaria has been related to terrible effects. In addition to local inflammatory signs, such as edema and erythema, systemic symptoms of poisoning were experienced after holding the corals, by intact as well as damaged skin.
Among them, dysgeusia and perioral paresthesia were the most ordinary ones and, in the most critical cases, temporary changes of cardiac functions were also recorded. Dangerous effects by cutaneous exposure are generally treated with supportive intra-venous physiological fluids infusion and connections of corticosteroids and antihistamines. (Pelin et al., 2017).
Will palytoxin kill fish?
Well, the answer is NO. According to different studies, palytoxin is poisonous substances but it does not affect fish, crustaceans, and worms, who feed on the zoanthids. While palytoxin can kill stony (hard) coral, however not soft coral, so it isn’t prescribed to consolidate them in a similar tank (Sprung 2015). On the other hand, palytoxin can bioaccumulate in the body and cause poisoning in humans after fish and crab ingestion containing toxin accidentally but it has a least direct effect on the body (Deeds 2011, Gussow 2014, Schemmer 2008).
In 2017 a seven-member of the family from Australia hospitalized because everyone struggles to breathe due to the effect of palytoxin. One family member reportedly removed and scrubbed some corals or to remove unwanted, unattractive growths from the tropical saltwater aquarium.
The U.S. National Poison Data System published a recent report that at least 171 cases related to palytoxin exposure has been reported to different poison control centers between 2000 and 2014 (Environ. Toxicol. Pharmacol. 2017, DOI: 10.1016/j.etap.2017.08.010). However, the incident rate of these kinds of cases are very rare and only happen due to utmost uncared.
The poisonous substance is dangerous and being exposed to it can have conceivably hazardous results. To keep yourself safe, individuals ought to keep general handling of corals to a minimum.
Wearing protecting eyewear and gloves once holding the coral will facilitate. Use bleach when you want to remove a growth from corals it will deactivate palytoxin.
Palytoxin can cause strong vasoconstriction which considered to be the second most non-protein poisonous substances. The best treatment for vasoconstrictor are vasodilators when injected immediately after exposure to a toxin, such as an isosorbide dinitrate, and papaverine and these vasodilators can be used as an antidote.
But this is not an effective treatment for palytoxin poisoning. Sometimes Supportive treatment, for example giving intravenous fluids for hypotension, and anti-arrhythmic, may provide some help. Obviously, the best treatment for any condition is prevention and the best prevention is personal protective equipment (PPE). Wear long gloves and eye protection, a face mask is advisable to avoid vaporization from palytoxin. Instead of bubbling rock for reuse, soak rock and coral in 10% bleach for thirty minutes to neutralize sufficiently any remaining zoanthids and kill any remaining palytoxin (CDC, Lowes 2015).
If doable, clean zoanthid containing rock outside, however if that’s unfeasible and live coral should be handled in an inside area, open windows and run an exhaust fan for proper ventilation and try not to wash with pressure stream or use a band-saw on zoanthid containing rock, as this may aerosolize palytoxin also (Sprung 2015).
Once treating zoanthids that are overgrown with hair alga, keep the hydrogen peroxide (H2O2) dip short. Keep any water that has contained zoanthids away from pets and children, as ingestion of palytoxin can be fatal. There are no official prescribed procedure or evidenced-based guidelines from CDC how to handle palytoxin as research still needs to be done
Are all Zoanthids toxic?
There is a myth that is Zoanthids contain palytoxin even many knowledgeable aquarists incorrectly state that all “zoanthids” toxic and are therefore dangerous, which is not accurate whatsoever.
Such blind statements show a lack of expertise in these corals. Recently, one such report published which quantify the actual concentration of palytoxin found in coral Zoanthids which are commonly sold in the market. During investigations, scientist found that many zoanthids species are non-toxic such as Zoanthus sansibaricus, Palythoa mutuki, and Zoanthus Kuroshio. They found that there is likely a single lineage of button polyps which is truly dangerous to the general aquarium community, for example, Palythoa heliodiscus.
Basically, there are no home tests to decide whether a coral contains palytoxins or not until indications show up after ingestion. If you have these animals in your reef tank, be aware of the danger they pose and handle them with care and admire their color from the other side of the acrylic or glass.
Can Coral kill you?
The distinctive coloured flower looking coral is famous in saltwater aquarium shows, yet under that mesmerizing move of colours lies a possibly lethal mystery. Coral brings beauty and colour to a home fish tank, but it also brings a diversity of naturally existing toxins. In fact, all corals in the ocean are challenging for space so they all want their territory and some of their mechanisms to defend themselves by releasing a deadliest toxin (palytoxin).
The direct effect of this toxin is very least only skin rashes but if you eat accidentally with fish or crab it could kill you. There have been situations where individuals passed on in the wake of eating food containing palytoxin or toxic substances similar to it. In the Philippines, the individual died after taking Demania reynaudii, a crab species containing palytoxin. People who had eaten smoked fish and parrotfish experienced near-fatal poisoning in Hawaii and Japan respectively.
How long does palytoxin last?
It depends on the palytoxin route of transmission into the body. If the toxin injected after food eating or administration by intraperitoneal route in different animals the symptoms have appeared in 30–60 minutes. However, if the body exposure to a toxin such as eye-exposure symptoms has appeared after 4 hours.
For comparative purpose, in some non-lethal cases, the symptoms in people have appeared in 6–8 hours after inhalation or skin exposure, and have lasted for 1–2 days
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