What is Coral Toxicity?

Corals are spineless creatures belonging to the class Anthozoa and the group Cnidaria. They are primarily found in the ocean, where they live in close-packed groups, each one forming lots of small organism called polyps. They are of vital importance as they construct reefs in tropical seas. Some corals, specifically the Zoanthid type or soft corals, are cherished in home or public aquariums as they are gorgeous and don’t require much upkeep. However, some Zoanthid species contain a potentially deadly chemical, palytoxin, making them toxic. Those who handle these corals in aquarium stores or at home may be more susceptible to exposure. Despite posing significant health risks, these risks often go underestimated or unnoticed due to the limited number of reported cases.

Palytoxin (PTX) is a highly poisonous non-protein substance. It is among the largest polymer compounds naturally found, with a molecular weight of 2680 kilodaltons. The lethal amount for mice, if given directly into the bloodstream, is 150 nanograms for each kilogram of body weight. PTX is also present in certain fish, algae, and specific marine bacteria. Cases of toxicity from non-coral sources have been reported frequently as well.

Recently, there has been a growing concern about the influence of PTX on human health due to contact with soft corals. The rate of poisonings, mostly among aquarium enthusiasts who handle PTX-laced soft corals, is steadily increasing. This rise can be attributed to inadequate regulation over coral trading and limited understanding and disregard for the threat that PTX poses.

What Causes Coral Toxicity?

The toxicity from Palytoxin (PTX), which is found in certain corals, is most commonly experienced when someone inhales vapors while cleaning or removing the coral from aquariums. Since these types of corals can grow quickly, they often need to be removed from parts of the aquarium where they’re not wanted. This is typically done by boiling them or scrubbing them off rocks. However, doing this can create steam or tiny droplets in the air, which people can breathe in.

In exposure can also happen through the skin, if someone handles corals that have PTX in them for a long time without protection. This can happen whether the skin is intact or broken.

Another way PTX can affect people is through eating seafood that either produces PTX or has been contaminated by the toxic corals. There have also been cases of eye toxicity due to PTX.

Risk Factors and Frequency for Coral Toxicity

Zoanthids, or sea anemones, are generally found in the tropical and subtropical oceans. They’re found along the coastlines of places like Hawaii, Florida, Brazil, Australia, Japan, and many islands in the Atlantic. They tend to live on the hard-bottom floors of shallow ocean waters, up to about 12 meters deep. Despite being sea-dwelling creatures, they’re easily available for purchase online, which means people can come into contact with them anywhere.

Most commonly, people who keep aquariums are the ones who experience toxicity from Zoanthids. In fact, there’s been a rise in cases where people inhale the toxins while cleaning their aquariums or handling the coral for long periods of time.

Signs and Symptoms of Coral Toxicity

There’s growing evidence that people can be exposed to palytoxin (PTX) through inhaling or touching PTX-contaminated soft corals. The severity of the poisoning from PTX depends on how long the exposure lasted, how the person was exposed, and how close they were to the coral. People generally seek medical help a few minutes to hours after upkeep of home aquariums. A comprehensive account of what the person was doing before symptoms appeared as well as information about their hobbies and jobs can provide helpful insights.

Usually, people recount an incident where they handled corals, often by boiling water and scrubbing corals off rocks. This can lead to breathing in vapors that cause symptoms. Often reported symptoms are:

Runny nose
Cough
Shortness of breath
Weakness
Muscle pain and cramps
Damage to skeletal muscles (rhabdomyolysis)
Tingling sensation
Seizures
Dizziness
Numbness
Restlessness
Fever
Nausea or vomiting
Rapid heart rate
Low blood pressure

Touching corals for an extended period with either intact or damaged skin might allow the toxin to be absorbed through the skin, causing:

Localized swelling, redness, and itching
Tingling sensation around the mouth
Altered taste
Other non-specific system-wide symptoms

If the toxin gets in the eyes, it might cause symptoms of keratoconjunctivitis, including severe eye pain, red eyes, decreased vision, sensitivity to light, a feeling of having a foreign object in the eye, and a metallic taste.

In severe cases, patients might show signs of serious difficulty in breathing and blue-tinged skin (cyanosis), which could lead to worsening respiratory failure and possibly death.

Testing for Coral Toxicity

Diagnosing coral toxicity can be challenging because there is no specific test or imaging that can confirm it. Instead, doctors primarily depend on the patient’s history of exposure to particular types of coral and the symptoms they experience afterward. With this condition, symptoms can vary widely from person to person, so a detailed understanding of the history and strong clinical suspicion are vital for an accurate diagnosis.

While a compound called PTX, found in some types of coral, has been successfully identified using a method called high-performance liquid chromatography in public health cases, this is not routinely done for diagnosing individual patients. There is no test to assess the level of toxicity in humans accurately. In recent cases, a diagnosis was made after identifying a link between the symptoms and prior exposure to palytoxin and ruling out an infectious cause.

The evaluation process depends on the way the patient was exposed to the toxin and their symptoms. Some individuals may need an electrocardiogram (a test that records the heart’s electrical activity) or monitoring of their respiratory system.

Treatment Options for Coral Toxicity

So far, there’s no established antidote or standard treatment plan for Palytoxin (PTX) poisoning linked to corals. However, there are ways to manage symptoms and limit damage caused by the toxin. Treatment is usually determined on a case-by-case basis. If the toxin affects the skin or eyes, rinsing with water can help minimize the effects.

Several methods are being studied to manage the harmful effects of inhaling PTX. Some methods involve using inhaled medications (nebulized β-agonists) or steroids. Alternatively, treatment may involve a mix of non-steroidal anti-inflammatory drugs (NSAIDs) and β-agonists, or a combination of steroids and antihistamines. If the toxin is in contact with the skin, it’s essential to use treatments like intravenous fluid support, steroids, and antihistamines. For eyes mildly affected by PTX, artificial tears, steroid drops, and antibiotics are commonly used. Serious eye conditions such as corneal inflammation (keratitis) and ulcers may require surgery.

If a patient gets to the emergency room with shortness of breath, bluish skin, or breathing problems, immediate and intensive care is crucial as these can be signs of impending respiratory failure. Moreover, attention should be given to the possible toxic effects of PTX on the heart, as it can be monitored using an electrocardiogram.

Studies involving animals suggest that certain medications like vasodilators, papaverine, and isosorbide dinitrate could potentially act as antidotes. However, these were beneficial only when injected directly into the heart right after exposure. This method is not tested on humans yet, so it’s not a standard treatment at the moment.

If a doctor is trying to identify a patient’s ailment, they might consider whether the patient might have:

Acute Anemia (a condition where your body doesn’t have enough red blood cells)
Acute Gastritis (inflammation of the stomach lining)
Aspiration Syndromes (when someone accidentally inhales something into their lungs)
Congenital anomalies of the lungs (birth defects affecting the lungs)
Hematologic problems (issues related to the blood)
Intestinal Perforation (a hole in the intestine)
Metabolic problems (conditions that disrupt normal metabolism)
Portal Hypertension (high blood pressure in the liver’s blood system)
Pulmonary air leaks (air leaks in the lungs)
Renal Artery Aneurysm (an abnormal bulge in a blood vessel in the kidney)
Small Intestinal Diverticulosis (presence of small pouches in the intestine)
Upper Gastrointestinal Bleeding (bleeding from the upper part of the digestive system)

It’s crucial for the doctor to rule out these possibilities through relevant tests to establish the correct diagnosis.

What to expect with Coral Toxicity

Patients with a mild exposure and minimal symptoms may only need treatments for symptoms and recover nicely. However, in severe cases, where symptoms include respiratory failure, heart toxicity, eye inflammation, muscle tissue breakdown, and kidney failure, there’s a considerably higher risk of serious illness and death.

Possible Complications When Diagnosed with Coral Toxicity

PTX toxicity from coral can cause several issues, which can vary based on how and for how long you were exposed. Mild poisoning may have local symptoms and general systemic symptoms. If the poisoning is severe, it might cause damage to the heart muscles, intense shortness of breath, fluid in the lungs, the breakdown of muscle tissue, kidney failure, loss of consciousness, and death due to heart or respiratory failure. Direct contact with the eyes can cause corneal damage and even eye puncture.

Common Symptoms and Complications:

Local symptoms
General systemic symptoms
Heart muscle damage
Intense shortness of breath
Fluid buildup in the lungs
Breakdown of muscle tissue
Kidney failure
Loss of consciousness
Death due to heart or respiratory failure
Eye damage
Eyeball puncture

Preventing Coral Toxicity

Over recent years, an increasing number of cases have shown that contact with a toxin called PTX can happen when handling soft corals, most commonly when cleaning and maintaining aquariums at home and public places. This issue has grown due to the potent toxicity of PTX found in these soft corals, in combination with the unregulated sale of these marine plants. With the rising frequency of poisonings, this issue has become a significant health concern.

For those who have an aquarium with any type of coral, it’s crucial to assume that palytoxin (PTX) might be present and to take precautions to avoid exposure. Aquarium owners should limit their direct contact with the corals as much as possible and always wear protective gear, such as gloves, masks with activated charcoal filters, and glasses, if they need to handle them. It’s also important to handle the corals gently and avoid harsh scrubbing or boiling, which can release harmful vapors and particles into the air. Some experts suggest that the safest way to deal with these types of corals is to have them removed by a trained professional. Using activated carbon treatment can purify the tank water by removing over 99% of PTX.

Public health advocates can contribute to reducing the risk of these poisonings by focusing their efforts on educating the public about this emerging health threat. Laws regulating the purchase and sale of corals could also increase public awareness and help reduce the number of poisoning cases in the future.