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  Discussion on HORSE DEATH DUE TO GAS FROM TOXIC ALGAE
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Member:
vickiann

Posted on Tuesday, Aug 11, 2009 - 11:45 am:

Found this interesting and a good reminder to stay out of algae blooms whether they are in salt or fresh water. (Fresh water algae blooms may contain neurotoxins).:

A horse died and its owner fell unconscious within seconds of falling into decomposing green seaweed along the northern coast of Brittany, France, last week, according to several sources.

Vincent Petit, DVM, PhD, said he was hand-leading his 15-year-old English Thoroughbred gelding along a beachside road after riding a long stretch of gallop when both he and the horse slipped into an algae-filled sludge nearly up to the horse's withers.

"I cried for a man on a tractor to throw a rope, and then I looked at my horse and saw that his nose was falling into the sludge," Petit said. "I held his head up for him, but a few seconds later he went into respiratory arrest, without even a fight. It was incredibly fast."

Petit said that he became unconscious immediately after that and did not recover until he had been moved out of the sludge by a passersby who had prevented him from DrOwning after he lost consciousness.

"The rapid onset of death and loss of consciousness in this case strongly suggest that we are dealing with a poisonous gas emitted from the decomposing algae," said Pierre Philippe, MD, an emergency room physician at the hospital where Petit was transferred.

Although initial veterinary reports cited the cause of the horse's death as asphyxiation, the autopsy results show no signs of DrOwning. However, they tend to support the theory of gas poisoning, particularly the acute pulmonary edema, with the horse's lungs "filled with blood," Petit said.

Petit and his horse might have broken through a sort of white "crust" that can form over decomposing green algae, suddenly releasing dangerous levels of hyDrOgen sulfide, according to Claude Lesné, MD, CNRS, researcher and toxicologist specializing in airborne pollutants at the Department of Public Health of the University of Rennes Medical School.

The horse might have succumbed to the gases faster because he had been galloping, as physical effort significantly increases exposure to toxic gases, Lesné said. "He could have even been already breathing lower doses of the gas before the accident. But research also suggests that generally humans are more resistant to toxicity than animals," he said. He added that two dogs had died in a similar accident in the same location last year.

Green algae-covered beaches are becoming more common worldwide, according to Lesné. "If the beach smells of rotten eggs, stay clear of it," he said, "especially if physical effort is involved."
Moderator:
DrO

Posted on Wednesday, Aug 12, 2009 - 6:13 am:

I would like to say that this is not so much an algae produced gas as it is a hyDrOgen sulfide (H2S) gas caused by decomposition of a sulfur rich organic material in a low oxygen environment. So not only are decomposing algae deposits a possible source of a "swamp gas mixture" but any where there is large amounts of organic decomposition, swamps, septic pits, and even barns have been reported sources of poisoning.

A few other notes about what I read while researching this subject:
  • As a cellular poison, H2 S affects all organs, particularly the CNS and pulmonary system. The spectrum of illness depends on the concentration and duration of exposure, with low concentration irritating the eyes and respiratory system. High concentrations (>700 ppm or >975 mg/m3) cause sudden death possibly due to hyDrOgen sulfide effect on the brainstem respiratory center.
  • Patients exposed to continuous low-level concentrations or after acute exposure to the very high concentrations of hyDrOgen sulfide can lose their ability to smell/detect the gas even though it is still present in the environment (olfactory fatigue/paralysis).
  • As a cellular poison, H2S affects all organs, particularly the CNS and pulmonary system.
  • It is very important to realize that 25% of fatalities usually involve rescuers, professionals, or bystanders. Rescue should be attempted with support like a rope attached to the rescuer so they can be pulled free if they loose consciousness.
  • If exposed to hyDrOgen sulfide, children are more vulnerable than adults.

DrO
Member:
vickiann

Posted on Wednesday, Aug 12, 2009 - 6:24 am:

Very interesting information.

Thanks, Dr. O.
Member:
lvmyhors

Posted on Wednesday, Aug 12, 2009 - 5:10 pm:

Thank you for this very interesting article! I find it especially so because many years ago, 8 to be exact, my mare was exposed to something on our rental property that caused her to become VERY ill! She exhibited all the signs of tetanus, but having had all of her vaccinations kept up to date my Vet searched for other possible causes to her symptoms. After many blood tests all that he was ever able to determine was that she had come into contact with something that had effected her nervous system and he honestly felt that she had been poisoned. This lasted for about one week and by the grace of God and one very determined owner we pulled her thru and she is still with me at the ripe old age of 28! I am now wondering if she had come into contact with some toxic agae in the irrigation ditch that ran through part of the property?!
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