Anatoxin-A: Very Fast Death Factor Erika Baca, Promise Bood, Korazon Romero

Drink up buddy, this water is all natural, so it’s completely safe! WRONG!! ...dang humans always trying to kill me...

Anatoxin-a Potent neurotoxin produced by cyanobacteria in freshwater environments: Lakes Rivers and streams Ponds Observed to cause death in: Cattle Flamingos Man’s best friend Humans

Absorption Gastrointestinal Tract Skin Lungs Ingesting fish or shellfish from waters containing anatoxin-a Consuming contaminated drinking water Skin Having direct skin contact with water containing anatoxin-a through bathing, showering, swimming or wading Lungs Breathing airborne anatoxin-a while boating, waterskiing or other recreational activities

Distribution After entering the circulatory system, some of the toxin will be transported into the Central Nervous System (CNS). Anatoxin-a is a small, hydrophobic molecule, which is why it can cross the BBB.

Mechanism of Action Anatoxin-a is a structural analogue to the neurotransmitter acetylcholine. It is an agonist of the nicotinic acetylcholine receptor. Anatoxin-a has a higher affinity for the receptor than acetylcholine The toxin binds irreversibly to the acetylcholine receptor, causing muscle contractions that cannot be released.

Muscle fasciculations Tingling Signs Symptoms Muscle fasciculations Tingling Paralysis Burning Convulsions Numbness Respiratory arrest Drowsiness Incoherent Speech Salivation Toxicity Humans LD50= 200-250 ug/kg Dogs Three dogs who died in Canada had stomach concentrations of 1ug/g Differences in lethal doses indicate that there is likely interspecific differences in tolerance to this toxin.

Metabolism Anatoxin-a cannot be degraded by acetylcholinesterase Neurons cannot return to the resting state The sodium channel of the muscles remained open Overstimulation and fatigue of muscles due to postsynaptic depolarizing activity Eventually, respiratory muscles are impacted Brain will experience a lack of oxygen Suffocation will occur a few minutes after exposure

Excretion Anatoxin-a cannot be degraded, so it remains active in the nervous system until death of the victim. Anatoxin-a is lethal to animals and humans that consume it, and exerts its effects in as little as four minutes. Because of this, this toxin is also known as the “Very Fast Death Factor.”

Prevention A cyanobacteria bloom is a rapid increase and accumulation of population in waters. Chlorine-based water treatment processes are ineffective, and do not inactivate the toxin. Ozone, potassium permanganate, and oxidation processes can be successful in treating water and inactivating the toxin.

Discussion Anatoxin-a is an extremely lethal cyanotoxin that has been observed to cause death in a variety of mammals. A very common exposure pathway is through ingesting water with algal blooms. We need to be aware of the risks of drinking untreated water, not only for the sake of humans, but also for livestock and pets.

Conclusion Anatoxin-a is being looked into for potential medicinal use in studying the nicotinic acetylcholine receptor and neuromuscular action. No current treatment for anatoxin-a exposure currently exists, giving potential for future research in this area. Just because things are natural does not mean we don’t need to be precautious “Detection of anatoxin-a is essential to ensure the biological safety of water environments”

References Aráoz R., Molgó J., Nicole Tandeau de Marsac, N. (2010): Neurotoxic cyanobacterial toxins. Toxicon 56, 813–828. Chorus, I. and Bartram, J. (1999) Toxic Cyanobacteria in Water: a Guide to Public Health Significance, Monitoring and Management. E & FN Spon /Chapman & Hall, London, 416 pp. Environmental Protection Agency. (2014). Cyanobacteria and Cyanotoxins: Information for Drinking Water Systems. 1-11. Puschner, B., Hoff, B., & Tor, E. R. (2008). Diagnosis of Anatoxin-a Poisoning in Dogs from North America. Journal of Veterinary Diagnostic Investigation, 20(1), 89–92. Santos, Douglas Silva Dos, et al. “Neurotoxic Effects of Sublethal Concentrations of Cyanobacterial Extract Containing Anatoxin-a(s) on Nauphoeta Cinerea Cockroaches.” Ecotoxicology and Environmental Safety, vol. 171, 2019, pp. 138–145., doi:10.1016/j.ecoenv.2018.12.068. Westrick A., Judy, Szlag J., Benjamin. (2010): A review of cyanobacteria and cyanotoxins removal/inactivation in drinking water treatment. Analytical and Bioanalytical Chemistry 397, 1705-1714. WHO; Cyanobacterial toxins: Microcystin-LR in Drinking-water. Background document for development of WHO Guidelines for Drinking-water Quality. (2003).