Public health threats are events or disasters that can affect you and your community. Examples of public health threats are:
- Natural disasters.
- Disease outbreaks.
- Accidents involving hazardous substances.
- Terrorist attacks.
Public health threats can affect air quality, cause shortages of safe water and food, and cut off electricity, gas, telephone, and other services. You and your family members may be separated.
Disasters are hard to predict and usually are out of your control. But you can take steps to help keep yourself and your family safe.
Preparing for disaster
Here are some things you can do to help prepare for a disaster:
- Learn about specific health threats and what you can do to reduce the risk to your health and safety. This topic helps you understand how health hazards can spread through a community and how you can limit your exposure to them.
- Make an emergency plan and gather the supplies you may need during an emergency. This topic includes tips on making an emergency plan and a supplies kit.
- Learn basic first aid skills such as CPR. And know where to find first aid information in case of injuries. For example, you can keep a first aid book in your emergency supplies kit.
- Always look to local authorities and health experts for specific, up-to-date information for your area. Follow their advice, even if it differs from this topic.
Following these steps can help you be better prepared for any type of public health threat.
Health threats in your community
There are many things in our environment that can be harmful. Chemicals, fumes, viruses, bacteria, and low-level radiation are just a few of them. When these substances are released in large quantities or get out of control, they can become urgent public health threats. Guidelines for how to prepare for and avoid a problem often depend on how the substance is spread.
In general, a health threat may spread through a community:
- In the air.
- In the water supply or food.
- From human to human.
- From animal or insect to human.
Call your local health unit for information about health threats in your area.
Chemicals are the most likely source of air contamination. An accident at a plant or factory or a train wreck might release large amounts of a hazardous chemical into the air, for instance. A terrorist attack could involve the deliberate release of a toxic chemical or gas.
In a bioterror attack, bacteria or viruses causing diseases such as anthrax, pneumonic plague, smallpox, or tularemia could be released in an aerosol form. Anyone who inhaled the substance could be affected.
Although air itself does not become radioactive, the release of radiation into the environment can create radioactive dust and dirt (fallout) that can make the air unsafe. A "dirty bomb" could work in this manner, causing a relatively minor explosion but doing its real damage by releasing radioactive materials into the environment.
What you can do
You cannot do much in advance to protect yourself from a hazardous substance released into the air. If there hasn't been an obvious explosion or a known terrorist attack, the air could become contaminated without anyone knowing it until people or animals start to have symptoms.
As with other potential emergencies, it makes sense to have a disaster kit with water, food, first aid items, tools, and other essentials. Concern over terrorist threats has prompted some people to consider adding the following items to their supplies:
- Duct tape and plastic sheeting for "sheltering in place." Sheltering in place involves temporarily sealing yourself inside a room in your home or another indoor location and shutting off sources of ventilation so that outside air doesn't get in.
- Masks. Different kinds of masks are available, such as surgical masks and gas masks. A surgical mask can help protect against some infections (such as SARS). But it will not protect against many other substances. A gas mask can protect against many toxic gases and other harmful substances in the air. But gas masks are expensive and hard to use. In general, masks are helpful only if you know how and when to use them and if they are properly fitted. They are not recommended for the general public. You do not need to purchase or wear any kind of protective mask unless civil or health authorities in your area tell you to do so.
- Potassium iodide tablets. Potassium iodide, also known as KI, helps protect your thyroid gland from the harmful effects of radioactive iodine, which could be released as a result of a dirty bomb, an explosion at a nuclear power plant, or any other nuclear incident. The KI is taken up by your thyroid gland and prevents the radioactive iodine from accumulating there. Potassium iodide does not protect against any other radioactive substances.
Vaccines for anthrax and smallpox are available for certain high-risk groups but are not recommended for the general public at this time. A vaccine for avian influenza was approved for use in Canada in 2013. But it is not available for the public. Canada keeps a stockpile of the vaccine. It would be used if the virus became able to pass from one person to another. The virus has not been able to do this for the 30 years since it was discovered. For more information, see Bioterrorism and Vaccinations.
If a hazardous substance is released into the environment:
- Get out of the immediate area if possible. If the release has occurred outdoors, go inside. If it has occurred indoors, go outside. Move out of low-lying spots to higher ground, because most chemicals released into the environment are heavier than air and will sink.
- Tune into a local radio or TV station for instructions from public health and emergency officials. Phones of government agencies are likely to be overwhelmed with calls during a public health emergency. So do not try to call for instructions. Information also may be available over the Internet. Depending on the kind of release, authorities may advise you to shelter in place or simply to stay indoors. You do not need to leave your community unless local authorities tell you to.
- If you are directly exposed to radioactive dust, dirt, or other fallout, follow the steps for personal decontamination to get the substance off your skin as quickly and completely as possible.
- Do not take potassium iodide (KI) tablets unless local authorities tell you to. These tablets are effective against radioactive iodine only. And they can be harmful if taken improperly.
Food and Water Contamination
Chemicals, heavy metals like lead and mercury, and living organisms such as bacteria and viruses can all be threats to a safe water supply. These substances can also contaminate food.
Unintentional contamination of water as a result of chemical leaks or spills, natural disasters, and other causes has been a much bigger problem than deliberate contamination. Likewise, accidental food contamination by botulinum toxin (the agent that causes botulism), E. coli, and other harmful organisms during the storage or preparation of food is much more likely than intentional food poisoning.
Intentional poisoning of food and water has occurred, though. The use of food and water to expose people to biological or chemical weapons is also possible. Terrorists could release living organisms such as the bacteria that cause tularemia or botulism into the water or food supply. Hazardous chemicals could be deliberately released in liquid or solid form. Radioactive materials could be released into the water.
What you can do
With the exception of a known accident (such as a chemical spill into the water supply) or an announced terrorist or criminal incident, you probably would not know that you had consumed contaminated water or food unless you developed symptoms. To reduce your risk of consuming contaminated food or water and to be better prepared for public health emergencies affecting the water supply:
- Don't eat food or drink water or any other beverage that looks or smells suspicious. In general, it is not a good idea to eat or drink something when you don't know who has prepared or provided it or where it has come from.
- When shopping, avoid food or beverage items that look like they may have been tampered with—for instance, if the seal is broken or you think that the container or packaging has been opened.
- Remember that most cases of foodborne illness (food poisoning), including botulism, happen by accident. Follow guidelines for preparing and cooking food safely, keeping your kitchen clean, and washing your hands and utensils. If you preserve and can foods at home, learn and follow proper canning and freezing techniques to ensure safety. Discard cans or jars with bulging lids or leaks.
- Know where your household's water comes from. Is it from the city water supply? Most public water supplies are carefully monitored and treated to guard against contamination. Does a private well supply your water? Private water supplies are unlikely to be targets of intentional contamination. But they can become contaminated by accident and may not be as closely monitored as city water supplies.
- Consider storing emergency water and food supplies.
- Learn how to purify water. And make sure that you include the supplies for this in your emergency kit. Knowing how to purify water is useful in any situation where you have to rely on untreated water.
If there is an emergency affecting the water supply:
- Follow all instructions from local authorities about purifying your water (commonly called "boil water advisories" or "boil water orders") or using other water sources until authorities notify your community that it is safe to drink from the regular water supply again.
- Do not strictly ration emergency drinking water supplies. Try not to waste any water, but drink what you need. On average, a person needs about2 L (2 qt) of water a day. Individual water needs vary depending on age, health, diet, and climate. Learn the signs of dehydration in children and adults so that you know what to watch for.
- Use the safest water you have first before turning to other water sources.
- If you know or suspect that your skin has come in direct contact with water that has been contaminated by a hazardous chemical or radiation fallout, follow the steps for personal decontamination to get the substance off your body as completely and quickly as possible.
Disease Transmission From Humans, Animals, and Insects
Some bacteria, viruses, and other biological agents can be spread from person to person or from animals or insects to people. The ease of international travel has made many of these health threats more difficult to contain. Recent health threats such as SARS (severe acute respiratory syndrome), the West Nile virus, and monkeypox have made people more aware of how easily disease can spread not only within a community but from one community to the next.
The Public Health Agency of Canada (PHAC), the U.S. Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) have current, reliable information on communicable diseases and health concerns throughout the world. For updates on specific health emergencies, visit their websites:
What you can do
To reduce your chances of being infected with or spreading a contagious disease:
- Wash your hands with soap and water often, especially if you live with or come into contact with someone who is sick.
- Do not share bedding, towels, utensils, or other items with someone who is sick or, if you are sick, with anyone else.
- Avoid exposure to disease-carrying animals and insects if you are in an area where these are a problem.
- Follow the advice of local health authorities if there has been a disease outbreak in your community or in an area where you are travelling. It is especially important to follow health experts' instructions if you live or work with someone who becomes sick. For instance, you may be advised to wear a surgical mask if you are in close contact with someone who has a serious contagious illness, such as SARS. Make sure you know how to properly fit and wear the mask.
- If there is an outbreak of a contagious disease in your area, do not leave the area unless authorities tell you to. If you have already been infected, you may spread the disease. Leaving the area may also cause a delay in your diagnosis or treatment.
Also see the Bioterrorism and Vaccinations section of this topic. A vaccine for smallpox is available for certain high-risk groups but is not recommended for the general public at this time.
Bioterrorism and Vaccinations
Health Canada and the Public Health Agency of Canada (PHAC), as well as provincial and local agencies, have developed plans on how to respond to bioterrorism threats. Certain diseases have been identified as posing the greatest threat. These diseases are:
Although the PHAC is addressing all of these potential threats, vaccines are available only for anthrax and smallpox. Currently these vaccines are not recommended for the general public. But the PHAC has advised special vaccinations for people at high risk for exposure to anthrax or smallpox, such as certain health care workers or military personnel. For more information, see:
Anthrax vaccine recommendations. The anthrax vaccine can be given for two reasons:
- To protect people at high risk of being exposed to anthrax. This type of vaccination is given in a series of shots over 18 months. Booster shots are then needed every year to stay protected.
- To treat people who have already been exposed to anthrax. For this purpose the vaccine is given as a series of shots over 4 weeks.
- Smallpox vaccination recommendations. The smallpox vaccine is given with a pronged device or a solid needle that delivers quick punctures to the upper arm.
A little organization can go a long way towards helping you feel ready to handle the unexpected. Having an emergency plan and an emergency supplies kit for your household can help you and your family be better prepared for any kind of disaster.
Developing an emergency plan
Putting together an emergency plan is easy:
- Choose a friend or relative as a contact person for family members to call if they are separated during a disaster. It is best to choose an out-of-province contact. Make sure every member of your household has the contact's phone number. Email may also be a good way to get in touch.
- Pick a place to meet outside your neighbourhood in case you cannot return home. Make sure every member of your household has the address and phone number. (Also designate a place to meet just outside your home—a neighbour's front yard, for instance—in case there is a fire in your home.)
- Write down where and how to turn off the water, gas, and electricity to the house. Make sure you have any special tools this requires, such as a T-wrench for the water line.
- Discuss what you would do if you had to leave your home and the area. Include your pets in your plans. Most emergency shelters and health facilities will not accept animals.
- Keep important documents, such as birth certificates, marriage licenses, wills, insurance forms, telephone numbers you might need, and credit card information together and readily available in case you need to quickly evacuate your home.
You may have other things that you want to include, especially if you have children in school or if anyone in your household has special needs. Review your plan yearly, and make sure that phone numbers, email addresses, and other items are still current.
Assembling an emergency supplies kit
The essentials of an emergency kit are the same no matter what the situation: food and water, first aid supplies and medicines, blankets and clothing, special-needs items (such as baby formula), and certain tools and household items, including a battery-powered radio, a flashlight, and extra batteries. You can also use a radio or flashlight that is powered by a hand crank and so does not need batteries.
Visit the Canadian Red Cross's website at www.redcross.ca for a checklist to use as you gather supplies. Store everything in one place, preferably a cool, dark location. Consider putting together a smaller version of your emergency kit that you could take if you had to leave home or shelter in place.
After you've assembled your emergency supplies, remember to check and replace them periodically:
- Bottled water that has remained sealed and unopened needs to be replaced once a year. Water in containers that you filled yourself needs to be replaced every 6 months.
- Follow the Red Cross's guidelines (www.redcross.ca) on how often to replace food supplies. Even "non-perishable" items may need to be replaced.
- Remember that both non-prescription and prescription medicines have expiration dates.
Information on disaster readiness
It is hard to prepare for a terrorist attack because no one knows what form it might take or when or where it may occur. But being prepared for general emergencies—including fires, natural disasters, power failures, fresh-water shortages, and similar events—makes sense and will help to reassure you and your family.
The following agencies provide extensive information about disaster planning and terrorism:
- The Canadian Centre for Emergency Preparedness and Response (CEPR) serves as the country's single coordinating point for public health security. Helpful links and answers to frequently asked questions are available from the CEPR website at www.phac-aspc.gc.ca/cepr-cmiu.
- The Canadian Red Cross has information on disaster readiness, including instructions on how to build a disaster supplies kit and how to make a disaster plan. You can access this information at www.redcross.ca.
The following resources from agencies in the United States may also be helpful:
- The American Red Crosshas specific disaster-readiness guidelines, including instructions on how to build a disaster supplies kit and how to make a disaster plan. You can access this information at www.redcross.org.
- The U.S. Federal Emergency Management Agency (FEMA) provides extensive information about national security emergencies, including chemical, biological, and nuclear attacks. You can access this information at www.fema.gov.
- The U.S. Centers for Disease Control and Prevention (CDC) provides answers to frequently asked questions about chemical and biological agents, such as toxic gases and smallpox, and nuclear attacks as well as advice on how to protect yourself. You can access this information at www.cdc.gov.
- The U.S. Department of Homeland Security urges citizens to be prepared and stay informed. Many helpful links are available from its website at www.dhs.gov/disasters or at www.ready.gov.
Responding to a Disaster
Dealing with injuries
In any disaster situation, transportation and communication may be interrupted, and medical services may be overwhelmed. You may need to evaluate or treat minor or major injuries or provide first aid, because medical care may not be immediately available. You may feel more confident when an emergency happens if you know what to do ahead of time and have resources at hand. The following topics discuss emergencies that can occur in a disaster situation:
- Back Problems and Injuries
- Chest Problems
- Confusion, Memory Loss, and Altered Alertness
- Head Injury, Age 3 and Younger
- Head Injury, Age 4 and Older
- Heart Attack and Unstable Angina
- Neck Problems and Injuries
- Nervous System Problems
Emergency procedures you may want to know include:
Injuries related to exposure and sanitation
A natural disaster, industrial accident, or terrorist attack can cause a lot of situations that lead to injury or illness. In some cases your home may need to be evacuated or may be damaged. A disaster may interrupt water supplies, food supplies, sewer and trash services, and heat and electricity. You may be exposed to the elements or have less-than-adequate shelter for a period of time. The following topics can help you avoid or cope with injuries related to food safety, sanitation, and exposure:
- Carbon Monoxide Poisoning (from appliances, fires, and generators)
- Foodborne Illness and Safe Food Handling
- Heat-Related Illnesses
- Hypothermia and Cold Temperature Exposure
- Insect Bites and Stings
The topic Dealing With Emergencies provides more information about how to cope with injuries that can occur during or right after a disaster.
You may feel overwhelmed after an accident, natural disaster, or terrorist attack. Some people who witness a traumatic event that seemed life-threatening develop a stress reaction known as acute stress disorder, which can last up to a month after the event.
Symptoms include feeling numb, reliving the event through disturbing memories or dreams, and avoiding anything that may be a reminder of the event. Symptoms are so intense that they disrupt daily activities like going to work and interacting with other people.
If the symptoms last more than a month or don't develop until more than a month after the event, you may have post-traumatic stress disorder (PTSD). Even if you were not injured or in danger, you can still get acute stress disorder or PTSD if you felt physically threatened or witnessed violence. For more information, see the topic Post-Traumatic Stress Disorder (PTSD).
People who have experienced or witnessed a traumatic event often need help from health professionals who are specially trained. If symptoms are severe enough to disrupt your daily life or do not improve after 2 weeks, talk with a doctor.
If you lost a loved one or friend in a disaster or accident (or even a pet, your home, or important possessions), you will need time to cope with feelings of grief and loss. For more information, see the topic Grief and Grieving.
Traumatic events can also cause feelings of depression that may need treatment. For more information, see the topic Depression.
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Brian O'Brien, MD, FRCPC - Internal Medicine
Kathleen Romito, MD - Family Medicine
Adam Husney, MD - Family Medicine
Christine Hahn, MD - Infectious Disease, Epidemiology
Martin J. Gabica, MD - Family Medicine
Current as ofMarch 29, 2018
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Current as of: March 29, 2018
Author: Healthwise Staff
Medical Review: E. Gregory Thompson, MD - Internal Medicine & Brian O'Brien, MD, FRCPC - Internal Medicine & Kathleen Romito, MD - Family Medicine & Adam Husney, MD - Family Medicine & Christine Hahn, MD - Infectious Disease, Epidemiology & Martin J. Gabica, MD - Family Medicine