Scientists have identified amyloid plaques, the folded proteins linked with Alzheimer’s, in the brains of dolphins stranded on the beaches of Florida and Massachusetts.
Analysis of the marine mammal brains also revealed the presence of BMAA, a toxin produced by cyanobacterial blooms.
“We found β-amyloid plaques and damaged neurons in brain tissues from dolphins that had died on the beaches of Florida and Massachusetts,” Dr. David Davis, a neurologist at the University of Miami, said in a news release.
Davis and his colleagues detailed their discovery in the journal PLOS One.
“Dolphins are an excellent sentinel species for toxic exposures in the marine environment,” said Dr. Deborah Mash. “With increasing frequency and duration of cyanobacterial blooms in coastal waters, dolphins might provide early warning of toxic exposures that could impact human health.”
In lab tests, scientists have previously confirmed exposure to BMAA triggers the formation of β-amyloid plaques and neurofibrillary tangles in the brains of animals — the same abnormalities found in the brains of patients with Alzheimer’s.
“We cannot say for sure that chronic exposure to cyanobacterial blooms can trigger Alzheimer’s in humans but it is a risk that I personally am unwilling to take,” said Larry Brand, oceanographer at the University of Miami.
Similar combinations of BMAA, β-amyloid plaques and neurofibrillary tangles were identified in the brains of the Chamorro people of Guam diagnosed with an Alzheimer’s-like neurodegenerative disorder called Lytico-bodig disease.
Still, scientists can’t yet say for certain whether the plaques and tangles caused the dolphins to strand themselves on the beach.
“Until further research clarifies this question, people should take simple steps to avoid cyanobacterial exposure,” said Paul Alan Cox, ethnobotanist at the Brain Chemistry Labs, a nonprofit researcher group in Jackson Hole, Wyoming.
How can I avoid exposure to algal toxins?
Avoid contact with algae-affected water, especially where discoloured water and visible scums are present. These scums are a build-up of algae that settles along the edge of the water, where you are more likely to make contact.
Follow advice on any harmful algae information signs present, and avoid contact with the water until authorities advise there is no longer a risk.
If you suspect that your local waterway is affected by harmful algae, contact the local waterway manager for further advice.
What should I do if I contact algae-affected water?
If you make contact with affected water, immediately leave the water. Remove any traces of algae by thoroughly washing and rinsing your skin and hair, contaminated clothes and wetsuits in clean water.
Can I swim and play other water sports in algae-affected water?
It is best to avoid direct contact with affected water including swimming and any other water sports.
Can I eat fish caught in waters affected by harmful algae?
Any fish caught from algae-affected waters should be washed in clean water, gilled and gutted. Put internal organs in the rubbish – it is likely that the fish has swallowed algal toxins, so don’t feed the leftovers to animals.
Do not eat any shellfish such as pipis, mussels, oysters, yabbies or crayfish from algae-affected water, as they are more likely to accumulate dangerous levels of algal toxins.
When algal blooms die and start to break down they use up oxygen in the water, which creates an environment that can suffocate fish. If you see fish that are dead, dying or swimming erratically, do not touch or eat them.
How do I keep animals safe from harmful algae?
Pets can be poisoned from contact with or ingestion of harmful algae. Do not let your animals swim in algae-affected areas, walk along banks where scums have accumulated or drink algae-affected water.
If your pet does come into contact with affected water or scums, wash them thoroughly with fresh water before drying so they do not swallow algae while grooming their fur.
If you are concerned about your pet’s health, consult your vet as soon as possible.
If you are a livestock owner, continuously check water supplies for harmful algae, and keep livestock away from algal blooms.
Can harmful algae affect my drinking water?
Yes. Algae can impact the smell and taste of water supplies.
If your local water business supplies your drinking water, they will manage any algae risks. If you have any concerns about the quality of your drinking water supply, contact your local water business.
If you use a private drinking water supply, you can prevent algae growing by sealing your water tank and ensuring the pipes or fittings do not receive sunlight.
How long do algal blooms last?
Harmful algal blooms will remain as long as there are favourable conditions, including warmth, sunlight and low flow rates. Blooms can last from weeks to months and it is difficult to predict when they will clear.
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