Communicable diseases

Communicable disease control

A communicable disease is an illness that can be contracted through contact with a human or animal, their discharges, or contaminated items carrying an infectious agent. An infectious agent is a disease causing organism, such as a bacteria, virus or parasite. Once a person has contracted a communicable disease they can then pass it on to others.

Environmental Health Officers at Northern Health routinely monitor illnesses that are transmitted from person to person or through food, water, animals, and insects. Many of these illnesses may be communicable, and thus be carried and transmitted by an infected person. Therefore, the prevention of these illnesses from being spread in a family or community is important because some of the illnesses can lead to serious illness and even death.

The most effective methods for preventing the spread of communicable disease are frequent handwashing and staying home when you are sick.

If you suspect you have a communicable disease, please seek medical care.

Please call HealthLink BC at 8-1-1 or TTY at 7-1-1 for the deaf and hearing-impaired. Registered Nurses can provide health information and advice at any time - 24 hours a day, seven days a week.

More information for non-urgent questions about illnesses and diseases:


Foodborne illness

Foodborne illness, often referred to as food poisoning, is the result of eating food contaminated with a disease causing organism (bacteria, virus, parasite, fungi) or with a toxin produced by a bacteria or fungi. Symptoms may range from mild to severe, and may include nausea, vomiting, diarrhea, abdominal cramps, and fever. In serious cases, severe complication can develop and, rarely, even lead to death. A person may also be carrying an illness but not be showing any symptoms. This is one reason it is important to practice good food safety.

Two main causes of foodborne illness are infections and intoxications. Infections take longer to present symptoms (for example days to weeks) while intoxications present more quickly (within hours to days). Some intoxications produce symptoms such as tingling in extremities, dizziness, difficulty breathing, paralysis and more.
Examples of common disease causing organisms are Salmonella, E.coli, Campylobacter, Listeria and S. aureus. For a more complete list, and details on each organism, refer to the BC Health files.

Environmental Health Officers follow-up on lab confirmed cases of organisms that cause foodborne illness. This follow-up involves contacting the individual who is sick and obtaining a detailed food history, as well as asking about certain high risk activities that make you more susceptible to the illness in question.
Following up on cases also helps identify outbreaks. EHOs investigate outbreaks to determine the cause and source of the illness. You will find more information on outbreaks on this page.

What if I think I have a foodborne illness?

If you suspect you have a foodborne illness, you should visit your doctor and describe your symptoms. To verify your illness, you will be asked to give a stool sample which will be sent for laboratory confirmation. Confirmation is necessary to determine the source or cause and provide information on limiting further spread. If you are suffering from a foodborne illness, you will be contacted by an Environmental Health Officer for follow-up.

Health Canada estimates that there are 11 to 13 million cases of foodborne illness in Canada every year. However, public health experts also estimate that only about one in five people seek medical attention when they suspect they’re suffering from such an illness, and of those only a small percentage have samples collected to confirm the presence of an enteric pathogen.

Waterborne illness

Waterborne illness is any illness that is acquired through the ingestion of water containing disease causing organisms (bacteria, virus, and parasites). This may occur when drinking untreated water that is contaminated (surface water such as ponds, streams and dugouts are of particularly high risk) or through ingestion while swimming.

Symptoms vary slightly depending on the organism, but can include nausea, vomiting, diarrhea, abdominal cramps, fever and more. These symptoms will usually appear within a few days of exposure, but may take weeks or even months to show.

Some handy tips for avoiding waterborne illness include:

  • Don't drink from a stream, river or lake no matter how cleaning and fast running it may be. Surface water is always at risk of contamination.
  • Get your own private well or water supply regularly tested and serviced to ensure that your family is being provided with safe water.
  • Make sure that your well or water supply is properly secured and vermin proof.
  • Ensure that your well or water supply is at least 30 metres or 100 feet away from any probable source of contamination.
  • Try to eliminate cross connections have install back flow preventers in your house to prevent contamination of your water supply and plumbing and to avoid drinking contaminated water.

Some examples of waterborne disease causing organisms are Giardia (Beaver Fever), Cryptosporidium, and E.coli to name a few. For specific information about these illnesses, and others, refer to the BC Health files.

Environmental Health Officers (EHOs) receive confirmed lab reports and perform a follow-up in the same way they would for a foodborne illness. A detailed history is taken of foods eaten, water sources used and other high risk activities (such as swimming in a lake) for the particular organism identified by the lab.

What if I think I have a waterborne illness?

Consult your doctor and discuss the symptoms you are experiencing. To verify which organism is causing your illness, you will be asked to provide a stool sample. The results of this sample will allow your doctor to determine the appropriate treatment. If you are suffering from a food or waterborne illness, you will be contacted by an EHO for a follow-up to determine the probable cause of the illness and discuss prevention measures to limit further spread.

Animal or insect borne illness

An animal or insect borne illness is one that is acquired from an infected animal or insect, usually through a bite or contact with infected parts of an animal. Sometimes a disease-causing organism may also be inhaled from dust that has been contaminated by an animal.

Some examples of these illnesses include Rabies, West Nile Virus, Lyme Disease, Q fever, Rickettsioses, and Hantavirus Pulmonary Syndrome. Symptoms vary from illness to illness - for more information on a specific illness, refer to the BC Health files

For more information on risk factors and prevention measures contact your local Environmental Health Officer.


Environmental Health Officers (EHOs) respond to all reports of animal bites to rule out the risk of rabies. In BC, rabies is only endemic (prevalent) in the bat population, and the rate of rabid positive bats is low. However, because rabies is fatal once contracted, follow-up should be thorough and immediate. The follow-up includes a detailed account of the incident and as much information about the animal as is available to determine if there is a risk for rabies.

Although the incidence of rabies in bats is rare, they are the only reservoir in British Columbia and as such, bats should not be touched or handled. If you must remove a dead bat it should be done with extreme caution using an instrument to keep it away from your body and while wearing thick gloves.

If you or your child has been bitten by or exposed to wild or unknown animal, seek medical attention immediately and contact your local health unit where a Public Health Nurse will verify your tetanus vaccination is up to date, and an Environmental Health Officer will perform a rabies follow-up.

You can also visit the BC Centre for Disease Control rabies webpage for more detailed information.

West Nile Virus

West Nile Virus is an infection that is spread my mosquitoes. There is no current active surveillance programs for West Nile Virus in Northern Health. Please visit the BC Centre for Disease Control for more information.

Outbreak control

Outbreaks and the role of EHOs

An outbreak occurs when more than two people have the same illness that can be linked back to one source or cause. Environmental Health Officers (EHOs) respond to reports of outbreaks around food or waterborne illness as well as Norovirus. EHOs will contact the ill individuals to perform a follow-up about food history, water source, events attended and more to determine a possible source or cause. Laboratory confirmation is necessary to determine the disease causing organism and to link cases in an outbreak. Knowing what organism is causing the illness also aids in determining what prevention measures are necessary to limit further spread.

When an outbreak is linked to a facility such as a care home, child care facility, school, etc., the EHO will do an onsite investigation and identify what control measures should be put in place. If an outbreak is linked to a water system, a Boil Water Advisory or Do Not Use notice may be issued. If the outbreak is linked to a food service establishment, an investigation will be conducted and necessary control measures implemented. If the outbreak is linked back to one food source, a recall will be initiated by the Canadian Food Inspection Agency (CFIA).


Noroviruses are a group of viruses that cause gastroenteritis in humans, the symptoms of which include nausea, vomiting, diarrhea, abdominal cramps, chills, body aches and fatigue. The symptoms usually appear suddenly 24-48 hours after exposure, and last approximately 24-60 hours. It is highly contagious and transmission is primarily through the fecal-oral route following direct contact with a person who is, or has been, recently ill. Fecal-oral transmission happens through contaminated hands-to-mouth, food-to-mouth, or fomites (objects)-to-mouth resulting in ingestion of the viruses. Noroviruses are responsible for a large number of outbreaks each year, particularly in winter months when people spend more time indoors and in close quarters.

The best way to protect yourself against a Norovirus illness is to wash your hands regularly, especially before eating, and for sick people to stay home while ill. Please visit the BCCDC Norovirus page for more information.