Long-term health effects in the survivors of Sarin gas attack and how does it affect us

The world woke up to the horrific scenes out of Idlib province in Syria where a yet another Sarin gas attack killed over 70 people. Thousands of casualties had occurred following a similar attack on Syrians in 2013. Here we briefly discuss about Sarin, its effects on the body, historical evidences for its exposure, and how unknowingly we are being exposed to low-levels of Sarin-like chemicals.

What is Sarin?

A chemical code-named GB was synthesized in the late 1930’s by German scientists Schrader, Ambros, Gerhard Ritter, and von der Linde who wanted to develop potent pesticides. Named Sarin after its inventors, once the Nazi army realized its lethal potential, they commissioned Sarin into warfare. However, it was not used during the Second World War. Sarin is considered as a weapon of mass destruction and its production and stockpiling is banned under the Chemicals Weapons Convention. Unfortunately this has not prevented its use by military regimes and terrorist organizations against civilians.

What happens after Sarin exposure?

In its purest form Sarin is a colorless and odorless liquid that can be pressurized into vapor form. Since one cannot see it or smell it, Sarin attack is a stealth one, and an individual may not know about the exposure until the symptoms begin. Sarin can be absorbed through skin, and breathed into lungs. It is extremely lethal, about 20-times more potent than cyanide, and even a single-drop can kill a human. Children are particularly vulnerable to its deadly effects. The first signs of Sarin exposure include salivation and foaming of mouth. Lacrimation and intense eye irritation follows. Exposed individual loses control over bodily function accompanied by urination and defecation. Flaying and jerking of limbs quickly evolve into full-blown seizures. This is followed by slowing of heart, labored breathing, and rapid death ensues. Depending on the severity of Sarin exposure, from the time of exposure to death is a matter of few minutes.

What is the mechanism of action of Sarin?

Sarin is an organophosphorus chemical. It inhibits an enzyme acetylcholinesterase. This enzyme is responsible for breaking down the neurotransmitter acetylcholine. Inhibition of this enzyme increases levels of acetylcholine at the synapses producing an exaggerated cholinergic response, which exhibits itself as symptoms described above.

What treatment options are available following Sarin exposure?

As seen in the videos from Syria, rescue workers were moving the exposed victims out in open, stripping their clothing and hosing off with water. The idea behind that is to first bring the victim in an open, well-ventilated area. Since Sarin can linger on the fabric, clothes are removed from the victim and he is scrubbed with water to wash-off Sarin residues from skin. The first-line of medical treatment includes administration of atropine. This drug controls the foaming and lacrimation. Pralidoxime that helps regenerate the enzyme which breaks down acetylcholine is also administered. Diazepam or midazolam is also administered if the exposed person is exhibiting seizures. These drugs are administered as needed till the symptoms have resolved.

What are the long-term consequences of Sarin exposure?

The currently available treatments are effective in rescuing the victims if the drugs are administered early after Sarin exposure. However, survivors endure permanent brain damage and develop long-term neurological illness. It is very likely that the survivors of Sarin gas attacks from Syria will suffer from various chronic illnesses chief among which would be neuropsychiatric issues such as mood disorders, depression, memory disturbances, and post-traumatic stress disorder (PTSD). Vision disturbances, cardiac issues, and breathing problems are also observed.

Are there other incidents of Sarin exposure?

The Gulf War Syndrome refers to chronic multi-symptom illness that afflicts about one-third of the Veterans that served during the First Gulf War (Aug 1990 to Feb 1991). Persian Gulf War is considered as a text-book example of American military precision and power. Over 700,000 soldiers were deployed in this war that lasted for few months including the buildup and the withdrawal. Shortly after their triumphant return from the Gulf, soldiers started complaining about a wide variety of health conditions. After a series of research investigations and probes by Congressional committees, it was concluded that prolonged exposure to a combination of pesticides that bears structural resemblance to nerve gas could have contributed to the development of these symptoms. In addition, during the deployment, US soldiers carried out destruction of bunkers that contained Saddam Hussein’s munitions. But some bunkers were holding rockets containing Sarin and Cyclosarin. Their accidental detonation set out a plume of nerve gas that according to meteorological and intelligence analysis lasted over a period of four days. It is believed that these exposures, although at low-levels, either alone or in combination produced nerve and brain damage resulting in symptoms of depression, mood disorders, pain, and cognitive deficits that are present even 25-years after the completion of the War.

In mid-90’s Japanese doomsday cult Aum Shinrikyo carried out multiple attacks using Sarin gas. On June 27, 1994 members of this cult released Sarin gas from a back of a truck in a residential area in Matsumoto. This attack killed 7 people and injured over 200 people. Then on March 20, 1995 members of this same cult attacked passengers in Tokyo subway using Sarin. This attack killed 12 people and injured over 5000 people. Many of these injured suffer from chronic illnesses to-date. The chief complaints in survivors are pertaining vision problems, PTSD, difficulty making decisions, anxiety, cognitive difficulties amongst others.

What is the relationship between Sarin and pesticides?

Outside of attacks and acts of domestic terrorism, civilians are getting exposed to Sarin-like compounds from the environment and food. Sarin bears chemical resemblance to some commonly used pesticides. While these organophosphate pesticides have been banned for household use in United States, they are widely used for agricultural purposes and as such are available without any restriction around the world. A low-level chronic exposure to this category of pesticides such as those experienced by agricultural workers has been reported to produce symptoms similar to those seen in the Veterans suffering from Gulf War Illness. Since these pesticides are potent, even a very low exposure in children continued over a period of time could produce toxicity. Studies have shown that children living near plantations where the use of organophosphorus pesticides is rampant exhibit neurobehavioral abnormalities, low IQ scores, and learning disabilities. There is also a concern that these pesticides could be transferred to nursing infants through their mother’s milk and potentially produce neurodevelopmental disabilities.

What is your area of research?

One aspect of our research is to uncover some of the molecular mechanisms underlying the development of chronic neurological conditions following Sarin-like exposures and then using this knowledge to develop medications for their effective treatment. Our laboratory is funded by a Department of Defense grant that will help us in identifying treatment options for Gulf War Illness syndrome. These therapies could also be useful for the management of long-term neurological problems in the survivors of nerve gas exposure.

(Dr. Laxmikant S. Deshpande is an Assistant Professor, and Dr. Kristin F. Phillips is a Research Scientist in the Departments of Neurology, Pharmacology and Toxicology at Virginia Commonwealth University, Richmond VA. Their laboratory research is on the long-term neurobehavioral effects of nerve gas and pesticide exposures. Email contact: Laxmikant.Deshpande@vcuhealth.org).