How nerve agent Novichok suspected in UK poisonings affects the body

Novichok may sound like a villain from a James Bond movie, but it’s actually a chemical weapon. The nerve agent has been blamed for the almost fatal poisoning of a former Russian agent and his daughter and, now, a British couple with no known spy connections.

What is it?The English translation for the word means “newcomer.” Although, this Russian nerve agent has been on the chemical weapon scene since the Cold War, it was one of the later generations of chemical weapons developed by the former Soviet Union, as reported by former government scientists.

What is it used for?
Ideal agents for chemical warfare have four main goals: effectiveness, toxicity, untraceability, and incurability -- especially for everyday citizens. Unlike the military, the average person is virtually unprotected and vulnerable.

Nerve agents are the most toxic of chemical warfare agents.

Nerve agents were developed during testing for insecticides in Germany, it was discovered that nerve agents were particularly lethal and thus could potentially be used for military reasons -- like creating a spray bomb. Although specific data on Novichok is scant, speculative and classified, it is a type of nerve agent thought to be created from common organophosphates.

Organophosphates can be found in drugs like pesticides and fertilizers. Nerve agents and insecticides both affect nerve function in the body. But unlike insecticides -- which are safer and used to specifically kill bugs, with high doses required to affect humans -- nerve agents are much more toxic and have a wider range of targets.

What does it do?Nerve agents work by “interrupting transmission of nerve function," Dr. Olen Brown, professor emeritus at the University of Missouri and author of "The Art and Science of Poisons," told ABC news.

They block a part of the nervous system that balances the amounts of acetylcholine (ACE), a chemical that affects all nerves related to the body, particularly muscles. The blocked part is called an acetylcholinesterase inhibitor (ACEi).

Stimulating nerves over, and over again, causes effects like excessive sweating and drooling, abnormal heartbeats, seizures, smaller pupils, confusion, nausea and vomiting, blurry vision and lots of tears, smaller pupils, and uncontrollable urination and diarrhea. Most importantly, muscles are particularly affected, like the diaphragm; it can become paralyzed from repetitive stimulation and eventually cause death by suffocation.

Though some nerve agents are made to kill instantly, newer nerve gases are made of multiple components that have to be combined to become lethal -- these are called binary compounds. Each part, by itself, may not be dangerous and thus could be produced in non-military, even commercial operations.

They are thus safer to transport and store -- factors that could make them bypass even tight security measures. Although drawbacks to binary compounds include the potential for delayed reaction time and thus delayed time to cause deadly effects.

What’s the antidote?“ACEi would normally work like an eraser and get rid of excess ACE like too much chalk on a chalkboard,” Brown, a toxicology specialist, told ABC News.

Nerve agents like Novichok effectively keep that eraser from working by grasping tightly onto it. There are drugs available to treat nerve agent poisoning: atropine and pralidoxime.

Atropine works to try and stop the activation of ACE and reverse some of the symptoms. Pralidoxime works by binding to the nerve agent to allow the body to rebalance ACE by restoring ACEi. The body itself will also, with time, make more ACEis and rebalance itself. But these drugs are limited -- pralidoxime can’t work if given too late, and “too late” can mean seconds after an exposure, depending on how it’s given and who it’s given to.

How is it transmitted?Nerve agents can be odorless, tasteless, and colorless. They can come in many forms. Vapors can be easily inhaled from the air; some can be dissolved into water to make liquids that can be put on clothes and absorbed by the skin. Although rare, some could even be crafted in a form that could be eaten.

Depending on the agent itself and how it’s released, the types of signs and symptoms, as well as timing, can vary. A liquid agent contacting the skin may not show effects for hours, but inhaling just one drop of the same agent could cause someone to stop breathing in seconds.

Is it contagious?Nerve agents that contaminate a person’s skin or clothes can affect others who touch it. Dosing is important, but as Brown explained: “These agents are really effective in tiny amounts, and unfortunately, they will kill most people.”

Clothing can trap vapors and pass a nerve agent on to others. It is also not reassuring that the environmental effects of nerve agents have yet to be finalized.

Are there medical tests?There are medical tests available to determine exposure, but they are not readily available. Nerve agent exposure could look like more common conditions, like a drug overdose.

How can I protect myself?Remember, the use of nerve agents is extremely, extremely rare. In general, there is a low risk for anyone to be exposed. Military personnel who work around chemical weapons may be at some risk of exposure. Learn more here.

Petrina Craine is an emergency medicine resident physician in Oakland, California working in the ABC News Medical Unit.