Weapons of mass destruction—threats and responses
http://www.100md.com
《英国医生杂志》
Introduction
Weapons of mass destruction (WMD) include chemical, biological, and radiological agents with the potential to cause death at low doses and with serious long term health effects in survivors. This article provides general information relevant to all situations, from terrorist attacks in developed countries to conflict zones in Third World countries. WMD agents can be used to terrorise or subjugate populations and wreak economic damage. Many agents are cheap to produce and can be deployed in different ways. As well as overt use, such as in bombs or by aerial spraying, they can be used covertly such as in packages sent in the post, via animal vectors, or by poisoning of water and food supplies.
Casualties from the attack on Halabja in northern Iraq by the former Iraqi government with multiple WMD agents, including nerve and mustard agents
Threats from WMD
The classic scenario of WMD use against civilians (the basis of many current exercises) is the release of the nerve agent sarin in the Tokyo subway. In this attack the actions of first responders and medical staff helped keep the final fatalities down to 12. Because they lacked protective clothing, however, many of these people absorbed sarin from victims' clothing and developed serious long term neurological complications. Other agents—such as mustard agent, VX, anthrax, and radiation—are more persistent and thus pose greater risks: doses to victims would be higher, attending staff would face protracted periods in protective clothing, and the threat would remain until full decontamination was achieved.
Threats from weapons of mass destruction
The diversity and gravity of threats are exemplified by the recent anthrax attack on the US Congress through the postal system. It claimed few victims, thanks to rapid intervention by bioweapons specialists, but it paralysed the postal system and cost over $6bn to clean up.
For the past seven years we have collaborated in a programme to treat and study the immediate and long term effects of WMD on the people of Halabja in northern Iraq. Our experiences have led us to draw up information about the risks from WMD agents, decontamination, immediate and long term effects, and responses to help victims and protect responders.
Subway passengers affected by sarin gas planted in central Tokyo attended by unprotected first responders and medical staff
Diversity of WMD agents
The range of potential WMD agents and delivery mechanisms is extensive. For chemical weapons, as well as highly toxic and persistent new agents such as VX, older agents, such as mustard gas, remain highly dangerous and relatively easy to obtain. For biological agents, the key element is rapid identification so that countermeasures can be deployed before the agent is widely disseminated. Biological toxins resemble chemical agents rather than infectious organisms: they can pose major threats, but usually only over localised areas or to poison food or water. Radiological weapons include weaponised radioactive waste and dirty bombs as well as nuclear weapons.
Chemical weapons: agents and effects
Chemical agents include vesicants (blister or mustard agents), nerve agents (sarin, soman, tabun, and VX), and blood agents (cyanide).
In the attack on Halabja 5000 civilians died immediately. The entire town of 80 000 was overcome, and there was no one to respond or provide medical support. The agents used included powerful and persistent carcinogens, resulting in many survivors with major long term illness
The former government of Iraq often used mustard and nerve agents in the same attack and weaponised chemical agents mixed with biological agents such as anthrax and aflatoxin. Use of more than one agent can lead to difficulties in detecting all the agents involved, increase mortality, complicate symptoms, and make decontamination more difficult
Mustard agent causes immediate severe damage to the respiratory tract, skin, and eyes, but skin blisters and corneal effects are not usually apparent for minutes to hours, though the characteristic garlic odour and burning sensation in throat and eyes may provide earlier warning. The carcinogenic effects of mustard agent begin within 2-4 minutes, and there are no antidotes. Long term effects include cancers; damage to respiratory, immune, and reproductive systems; and blindness. Victims need rapid decontamination to minimise effects.
Characteristic blistering of skin from exposure to mustard agent. The blisters resolve, but 30% of mustard agent victims have severe, irreversible damage to the skin, eyes, and lungs. Even those lacking these symptoms are at risk of serious future problems. Medical authorities should be concerned about all victims' future health and wellbeing
Nerve agents may be colourless and odourless and give little warning of their presence, but minute amounts can kill rapidly. Their immediate effects can be recognised with the acronym DUMBELS (diarrhoea; urination; miosis; bradycardia, bronchorrhoea, and bronchospasm; emesis; lacrimation; and salivation and sweating). Victims—especially those without protective clothing, gas masks, or antidotes—rapidly become unconscious, have breathing difficulties, and may die. Sarin, tabun, and soman are relatively non-persistent but tend to "off gas" as they evaporate, which can present a vapour hazard for first responders. VX persists for several days and is over 150 times more toxic than sarin and tabun and is therefore very dangerous. Warning signs may include symptoms or death in animals, birds, and insects. Nerve agents can have various long term effects from cardiac arrhythmias to major neuropathies.
Chemical WMD agents and their properties
Cyanide is extremely light and disperses rapidly in the open air but is dangerous at high concentrations in enclosed spaces.
Responses to food contaminated with chemical agents (mustard or nerve agents)
Responses to chemical WMD
An effective response to chemical WMD requires chemical detection or monitoring systems, antidotes where appropriate, rapid decontamination, and ensuring that exposed populations do not consume contaminated food and water or remain in contaminated environments. The sarin attack in Tokyo showed the vulnerability of civilian populations, first responders, and medical teams. Victims were overcome by a colourless, odourless, volatile agent; delays in identifying the responsible agent allowed contamination to extend to receiving hospitals, where staff failed to put on protective clothing and gas masks.
Antidotes for nerve agents include atropine, which works by blocking acetylcholine at the postsynaptic receptor sites, thus counteracting muscarinic effects. Because atropine does not affect nicotinic synapses, oximes such as pralidoxime are also given. Oximes bind with acetylcholinesterase and hydrolyse the nerve agent, but are effective only if given soon after exposure, otherwise nerve agent binding becomes irreversible. Because nerve agents act rapidly, responders must put on gas masks and protective clothing immediately to avoid becoming casualties themselves.
It is important not to delay decontamination. In the absence of specialised decontamination, household bleach (sodium hypochlorite) should be used. This is effective against nerve and mustard agents and many bioweapons, but it requires clear instructions about the correct dilution (1 in 10, such as 1 litre of bleach in 9 litres water) and of special precautions such as avoiding the eyes. Although direct contact with such a bleach solution would normally be considered unwise, rapid decontamination may save lives, especially for fast acting, highly toxic agents such as VX. In Halabja, Iraq, thousands died immediately and many survivors have severe long term problems because no decontamination was carried out on victims, the environment, or the unexploded bombs that harboured large amounts of native nerve and mustard agents.
Smallpox is very contagious, and lack of natural resistance or vaccine means it would be highly lethal
Bioweapons: bacteria, viruses, and toxins
Many potential biological agents exist, but we will consider only high risk (category A) agents. These pose the greatest threat to public health, may spread across large areas, carry a high risk of death, and are readily transmissible from person to person or are easily disseminated. The dangers are greatest when no vaccines or effective treatments are available.
Bioweapons can be countered by recognition of risks, accurate diagnosis, and rapid treatment. For most agents, specialised testing is necessary by public health specialists or laboratories. For bacterial agents, vaccination and treatment with antibiotics or antitoxins must be started early to prevent disease progression and death. For viral diseases, vaccination is the principal form of prophylaxis: the use of antiviral drugs might be useful, but effectiveness and safety have yet to be established.
Nuclear devices are unmistakable because of the thermal blast, but radiological dispersal devices such as dirty bombs (conventional explosives laced with radioactive isotopes in the form of pellets or powder) may not be immediately recognised if monitoring with a Geiger counter is not done. Monitoring (including identifying contaminated food, water, and milk) is crucial in any radiological incident, as are decontamination and providing iodine tablets if radioiodine is released.
Given the wide array of WMD and delivery mechanisms, preparedness for all possible events is extremely challenging. The basis of an effective response involves
Stay upwind and uphill
Monitor to identify agents (more than one may be used)
Decontaminate or isolate people affected
Give antidotes as appropriate for nerve agents
Provide treatment for bioweapons (antibiotics, vaccination)
Provide respiratory support if necessary (respiratory paralysis is a common primary event that is often temporary), but remember that victims may pose a risk to responders who lack adequate protection
Good communication and coordination of information from pharmacies, laboratories, first responders, emergency medicine, and medical and public health staff
Deal swiftly with any contaminated food, water, and environment to prevent casualties extending beyond those directly affected (the main cancers among survivors of the atomic bombs dropped on Japan were of the gut because of ingestion of contaminated food and water)
Preparedness measures include supplies of bottled water and safe food stored in non-permeable containers.
Long term effects of WMD
The long term health effects of WMD depend on the agent used, dose, route of exposure, and victims' genetic susceptibility. The Japanese atomic bombs resulted in cancers, infertility, and adverse pregnancy outcomes. Mustard agent can cause cancers of the head, neck, and respiratory tract, haematological malignancies, immune system dysfunction, infertility, and birth defects in offspring. Long term effects of nerve agents include neurological and psychiatric problems and cardiac arrhythmias.
Long term effects of WMD. These may be serious, depending on the agent, route of exposure, dose, and individual susceptibility. Prompt actions, such as decontamination, help to mitigate against long term health problems
Fetuses are especially vulnerable because, unlike children and adults, they lack most of the protective mechanisms for metabolising or protecting against WMD agents (thus, rates of leukaemia among the survivors of the Hiroshima bomb were far greater for those exposed in utero than for other age groups).
There has been little study or acknowledgment of the long term risks of WMD, because people have concentrated almost exclusively on short term problems. Long term risks may be severe and life threatening, but the lack of recognition of the sequelae means survivors receive no help.
Reducing these effects depends on deploying effective detection systems to alert to WMD risks, establishing systems for rapid responses with facilities for decontamination and treatment of casualties, providing information to the affected population, and providing uncontaminated food, water, and environment after an attack.
Professor Christine Gosden is professor of medical genetics and Derek Gardener is biomedical laboratory scientific officer at University of Liverpool, Department of Pathology, Royal Liverpool University Hospital, Liverpool.
Competing interests: None declared.
The ABC of conflict and disaster is edited by Anthony D Redmond, emeritus professor of emergency medicine, Keele University, North Staffordshire; Peter F Mahoney, honorary senior lecturer, Academic Department of Military Emergency Medicine, Royal Centre for Defence Medicine, Birmingham; James M Ryan, Leonard Cheshire professor, University College London, London, and international professor of surgery, Uniformed Services University of the Health Sciences (USUHS), Bethesda, MD, USA; and Cara Macnab, research fellow, Leonard Cheshire Centre of Conflict Recovery, University College London, London. The series will be published as a book in the autumn.
The picture of the Halabja massacre is reproduced with permission of CNN/Getty. The picture of the Tokyo subway attack is reproduced with permission of Chikumo Chiaki/AP/Empics. The picture of mustard gas blisters is supplied by Defence Science and Technology Laboratory, Porton Down, Salisbury. The picture of smallpox is supplied by the CDC Public Health Image Library.(Christine Gosden, Derek Gardener)
Weapons of mass destruction (WMD) include chemical, biological, and radiological agents with the potential to cause death at low doses and with serious long term health effects in survivors. This article provides general information relevant to all situations, from terrorist attacks in developed countries to conflict zones in Third World countries. WMD agents can be used to terrorise or subjugate populations and wreak economic damage. Many agents are cheap to produce and can be deployed in different ways. As well as overt use, such as in bombs or by aerial spraying, they can be used covertly such as in packages sent in the post, via animal vectors, or by poisoning of water and food supplies.
Casualties from the attack on Halabja in northern Iraq by the former Iraqi government with multiple WMD agents, including nerve and mustard agents
Threats from WMD
The classic scenario of WMD use against civilians (the basis of many current exercises) is the release of the nerve agent sarin in the Tokyo subway. In this attack the actions of first responders and medical staff helped keep the final fatalities down to 12. Because they lacked protective clothing, however, many of these people absorbed sarin from victims' clothing and developed serious long term neurological complications. Other agents—such as mustard agent, VX, anthrax, and radiation—are more persistent and thus pose greater risks: doses to victims would be higher, attending staff would face protracted periods in protective clothing, and the threat would remain until full decontamination was achieved.
Threats from weapons of mass destruction
The diversity and gravity of threats are exemplified by the recent anthrax attack on the US Congress through the postal system. It claimed few victims, thanks to rapid intervention by bioweapons specialists, but it paralysed the postal system and cost over $6bn to clean up.
For the past seven years we have collaborated in a programme to treat and study the immediate and long term effects of WMD on the people of Halabja in northern Iraq. Our experiences have led us to draw up information about the risks from WMD agents, decontamination, immediate and long term effects, and responses to help victims and protect responders.
Subway passengers affected by sarin gas planted in central Tokyo attended by unprotected first responders and medical staff
Diversity of WMD agents
The range of potential WMD agents and delivery mechanisms is extensive. For chemical weapons, as well as highly toxic and persistent new agents such as VX, older agents, such as mustard gas, remain highly dangerous and relatively easy to obtain. For biological agents, the key element is rapid identification so that countermeasures can be deployed before the agent is widely disseminated. Biological toxins resemble chemical agents rather than infectious organisms: they can pose major threats, but usually only over localised areas or to poison food or water. Radiological weapons include weaponised radioactive waste and dirty bombs as well as nuclear weapons.
Chemical weapons: agents and effects
Chemical agents include vesicants (blister or mustard agents), nerve agents (sarin, soman, tabun, and VX), and blood agents (cyanide).
In the attack on Halabja 5000 civilians died immediately. The entire town of 80 000 was overcome, and there was no one to respond or provide medical support. The agents used included powerful and persistent carcinogens, resulting in many survivors with major long term illness
The former government of Iraq often used mustard and nerve agents in the same attack and weaponised chemical agents mixed with biological agents such as anthrax and aflatoxin. Use of more than one agent can lead to difficulties in detecting all the agents involved, increase mortality, complicate symptoms, and make decontamination more difficult
Mustard agent causes immediate severe damage to the respiratory tract, skin, and eyes, but skin blisters and corneal effects are not usually apparent for minutes to hours, though the characteristic garlic odour and burning sensation in throat and eyes may provide earlier warning. The carcinogenic effects of mustard agent begin within 2-4 minutes, and there are no antidotes. Long term effects include cancers; damage to respiratory, immune, and reproductive systems; and blindness. Victims need rapid decontamination to minimise effects.
Characteristic blistering of skin from exposure to mustard agent. The blisters resolve, but 30% of mustard agent victims have severe, irreversible damage to the skin, eyes, and lungs. Even those lacking these symptoms are at risk of serious future problems. Medical authorities should be concerned about all victims' future health and wellbeing
Nerve agents may be colourless and odourless and give little warning of their presence, but minute amounts can kill rapidly. Their immediate effects can be recognised with the acronym DUMBELS (diarrhoea; urination; miosis; bradycardia, bronchorrhoea, and bronchospasm; emesis; lacrimation; and salivation and sweating). Victims—especially those without protective clothing, gas masks, or antidotes—rapidly become unconscious, have breathing difficulties, and may die. Sarin, tabun, and soman are relatively non-persistent but tend to "off gas" as they evaporate, which can present a vapour hazard for first responders. VX persists for several days and is over 150 times more toxic than sarin and tabun and is therefore very dangerous. Warning signs may include symptoms or death in animals, birds, and insects. Nerve agents can have various long term effects from cardiac arrhythmias to major neuropathies.
Chemical WMD agents and their properties
Cyanide is extremely light and disperses rapidly in the open air but is dangerous at high concentrations in enclosed spaces.
Responses to food contaminated with chemical agents (mustard or nerve agents)
Responses to chemical WMD
An effective response to chemical WMD requires chemical detection or monitoring systems, antidotes where appropriate, rapid decontamination, and ensuring that exposed populations do not consume contaminated food and water or remain in contaminated environments. The sarin attack in Tokyo showed the vulnerability of civilian populations, first responders, and medical teams. Victims were overcome by a colourless, odourless, volatile agent; delays in identifying the responsible agent allowed contamination to extend to receiving hospitals, where staff failed to put on protective clothing and gas masks.
Antidotes for nerve agents include atropine, which works by blocking acetylcholine at the postsynaptic receptor sites, thus counteracting muscarinic effects. Because atropine does not affect nicotinic synapses, oximes such as pralidoxime are also given. Oximes bind with acetylcholinesterase and hydrolyse the nerve agent, but are effective only if given soon after exposure, otherwise nerve agent binding becomes irreversible. Because nerve agents act rapidly, responders must put on gas masks and protective clothing immediately to avoid becoming casualties themselves.
It is important not to delay decontamination. In the absence of specialised decontamination, household bleach (sodium hypochlorite) should be used. This is effective against nerve and mustard agents and many bioweapons, but it requires clear instructions about the correct dilution (1 in 10, such as 1 litre of bleach in 9 litres water) and of special precautions such as avoiding the eyes. Although direct contact with such a bleach solution would normally be considered unwise, rapid decontamination may save lives, especially for fast acting, highly toxic agents such as VX. In Halabja, Iraq, thousands died immediately and many survivors have severe long term problems because no decontamination was carried out on victims, the environment, or the unexploded bombs that harboured large amounts of native nerve and mustard agents.
Smallpox is very contagious, and lack of natural resistance or vaccine means it would be highly lethal
Bioweapons: bacteria, viruses, and toxins
Many potential biological agents exist, but we will consider only high risk (category A) agents. These pose the greatest threat to public health, may spread across large areas, carry a high risk of death, and are readily transmissible from person to person or are easily disseminated. The dangers are greatest when no vaccines or effective treatments are available.
Bioweapons can be countered by recognition of risks, accurate diagnosis, and rapid treatment. For most agents, specialised testing is necessary by public health specialists or laboratories. For bacterial agents, vaccination and treatment with antibiotics or antitoxins must be started early to prevent disease progression and death. For viral diseases, vaccination is the principal form of prophylaxis: the use of antiviral drugs might be useful, but effectiveness and safety have yet to be established.
Nuclear devices are unmistakable because of the thermal blast, but radiological dispersal devices such as dirty bombs (conventional explosives laced with radioactive isotopes in the form of pellets or powder) may not be immediately recognised if monitoring with a Geiger counter is not done. Monitoring (including identifying contaminated food, water, and milk) is crucial in any radiological incident, as are decontamination and providing iodine tablets if radioiodine is released.
Given the wide array of WMD and delivery mechanisms, preparedness for all possible events is extremely challenging. The basis of an effective response involves
Stay upwind and uphill
Monitor to identify agents (more than one may be used)
Decontaminate or isolate people affected
Give antidotes as appropriate for nerve agents
Provide treatment for bioweapons (antibiotics, vaccination)
Provide respiratory support if necessary (respiratory paralysis is a common primary event that is often temporary), but remember that victims may pose a risk to responders who lack adequate protection
Good communication and coordination of information from pharmacies, laboratories, first responders, emergency medicine, and medical and public health staff
Deal swiftly with any contaminated food, water, and environment to prevent casualties extending beyond those directly affected (the main cancers among survivors of the atomic bombs dropped on Japan were of the gut because of ingestion of contaminated food and water)
Preparedness measures include supplies of bottled water and safe food stored in non-permeable containers.
Long term effects of WMD
The long term health effects of WMD depend on the agent used, dose, route of exposure, and victims' genetic susceptibility. The Japanese atomic bombs resulted in cancers, infertility, and adverse pregnancy outcomes. Mustard agent can cause cancers of the head, neck, and respiratory tract, haematological malignancies, immune system dysfunction, infertility, and birth defects in offspring. Long term effects of nerve agents include neurological and psychiatric problems and cardiac arrhythmias.
Long term effects of WMD. These may be serious, depending on the agent, route of exposure, dose, and individual susceptibility. Prompt actions, such as decontamination, help to mitigate against long term health problems
Fetuses are especially vulnerable because, unlike children and adults, they lack most of the protective mechanisms for metabolising or protecting against WMD agents (thus, rates of leukaemia among the survivors of the Hiroshima bomb were far greater for those exposed in utero than for other age groups).
There has been little study or acknowledgment of the long term risks of WMD, because people have concentrated almost exclusively on short term problems. Long term risks may be severe and life threatening, but the lack of recognition of the sequelae means survivors receive no help.
Reducing these effects depends on deploying effective detection systems to alert to WMD risks, establishing systems for rapid responses with facilities for decontamination and treatment of casualties, providing information to the affected population, and providing uncontaminated food, water, and environment after an attack.
Professor Christine Gosden is professor of medical genetics and Derek Gardener is biomedical laboratory scientific officer at University of Liverpool, Department of Pathology, Royal Liverpool University Hospital, Liverpool.
Competing interests: None declared.
The ABC of conflict and disaster is edited by Anthony D Redmond, emeritus professor of emergency medicine, Keele University, North Staffordshire; Peter F Mahoney, honorary senior lecturer, Academic Department of Military Emergency Medicine, Royal Centre for Defence Medicine, Birmingham; James M Ryan, Leonard Cheshire professor, University College London, London, and international professor of surgery, Uniformed Services University of the Health Sciences (USUHS), Bethesda, MD, USA; and Cara Macnab, research fellow, Leonard Cheshire Centre of Conflict Recovery, University College London, London. The series will be published as a book in the autumn.
The picture of the Halabja massacre is reproduced with permission of CNN/Getty. The picture of the Tokyo subway attack is reproduced with permission of Chikumo Chiaki/AP/Empics. The picture of mustard gas blisters is supplied by Defence Science and Technology Laboratory, Porton Down, Salisbury. The picture of smallpox is supplied by the CDC Public Health Image Library.(Christine Gosden, Derek Gardener)