Environmental Diseases and Infections

Pathogens, such as bacteria, viruses, parasites, or fungi, cause infectious diseases. These diseases can spread from the environment or from one person to another resulting in illness in our communities.

What we do

There are some diseases and infections that the environment can transmit to humans. Deer tick bites can lead to Lyme Disease, some mosquitos carry West Nile Virus, and rabies can infect some animals. 

NWHU conducts surveillance of different vectors to understand what the risk is in our area and educate the public on prevention methods. We also respond to animal bite reports and investigate incidents to reduce the risk of rabies transmission. Some of these diseases are all reportable, and we track any case in a human.

West Nile Virus

West Nile Virus

You can find West Nile Virus in infected mosquitos, and mosquito bites can transmit it to humans. The mosquito is infected by biting an infected bird. Most people infected with West Nile virus have no symptoms and do not feel sick. Some people will have mild symptoms that usually appear within two to 15 days after infection. These symptoms include fever, headache, body aches and mild body rash. Rarely, however, some people may become very ill and can result in long-term damage or death.  

NWHU carries out regular mosquito trapping during the summer months. We send these mosquitos for testing to measure what the risk might be in our area. 

The risk of coming into contact with the mosquitoes that carry the West Nile virus in our region is low. The risk, however, is not zero, and there is no way of knowing which of the mosquitoes biting you might be carrying West Nile virus.

Preventing West Nile virus

The best way to reduce your chances of infection with West Nile virus is to avoid mosquito bites. Take the following simple precautions to protect yourself from bites:

  • Use insect repellent containing DEET, Icaridin or other approved ingredients on clothing as well as exposed skin. Always read and follow label directions. 
  • Wear light-coloured clothing, a long-sleeved shirt and long pants. 
  • Make sure screen doors and windows are in good repair to keep mosquitoes outside. 
  • Empty standing water around your home and property (e.g. flowerpots, gutters, pet water dishes, and birdbaths) on a regular basis, because mosquitoes breed in standing water.

For more information on West Nile virus in our area, call 1-800-830-5978 or email talkpublichealth@nwhu.on.ca.

Tick-borne Diseases

Tick-borne Diseases

Tick-borne diseases occur when a person is infected with an illness from the bite of an infected tick. In northwestern Ontario, there are several species of ticks. The only species responsible for spreading tick-borne diseases to humans in our area is Ixodes scapularis (deer tick, or black-legged tick).  

Tick identification cards are available from NWHU that show the difference between wood (dog) ticks, which are not known to carry disease and the black-legged (deer) tick that can carry tick-borne disease. We also have “tick kits” available that include information as well as a tool to help to remove ticks that are stuck in the skin.

For more information about ticks and tick-borne diseases, use the following or visit our Ticks and Tick-Borne Diseases page.

What and where is Lyme disease?

Lyme disease is an inflammatory infection that spreads to humans through tick bites. 

Public Health Ontario identifies the Kenora; Rainy River and Fort Frances; and surrounding areas of each, as being an estimated risk area for Lyme disease.

For more information about Lyme disease, visit CanLyme’ Lyme Basics page.

Preventing tick bites

To help discourage ticks from being on your property, do the following:

  • Mow the lawn regularly. 
  • Remove leaf litter, brush, and weeds. 
  • Keep tree branches and shrubs trimmed to let in more sunlight. 
  • Move children’s swing sets and sandboxes away from the wooded or bushy edges of a play area.  Consider placing swing sets and sandboxes on a woodchip or mulch foundation. 
  • Ticks often attach themselves to rodents, deer and birds. Keep rodents away by sealing stone walls and small openings around the yard. Use plants that do not attract deer or consider fencing to keep deer out of the yard. If you have a bird feeder keep it away from the house.

For more information on ticks in our area, call 1-800-830-5978 or email talkpublichealth@nwhu.on.ca.

Discouraging ticks on your property

To help discourage ticks from being on your property, do the following:

  • Mow the lawn regularly. 
  • Remove leaf litter, brush and weeds. 
  • Keep tree branches and shrubs trimmed to let in more sunlight. 
  • Move children’s swing sets and sandboxes away from the wooded or bushy edges of a play area.  Consider placing swing sets and sandboxes on a woodchip or mulch foundation. 
  • Ticks often attach themselves to rodents, deer and birds. Keep rodents away by sealing stone walls and small openings around the yard. Use plants that do not attract deer or consider fencing to keep deer out of the yard. If you have a bird feeder keep it away from the house.

For more information on ticks in our area, call 1-800-830-5978 or email talkpublichealth@nwhu.on.ca.

Rabies and animal bites

Rabies and animal bites

Rabies is a virus that you can find in wildlife and animals across the province of Ontario. In Canada, foxes, skunks, bats, and raccoons most commonly transmit rabies. But, on rare occasions, you can also find rabies in pets.  

A bite or scratch from an infected animal is how rabies infects humans and animals. Once symptoms appear, if not treated, rabies is almost always fatal in both animals and humans. NWHU investigates every report of an animal biting a human.

Vaccinating pets for rabies

You must comply with the following:

  • All dogs, cats and ferrets over the age of 3 months in Ontario must be vaccinated regularly against rabies.
  • All horses, cattle and sheep intended to come into direct contact with the general public must also be vaccinated.
  • Horses, cattle and sheep which are only accessible to persons responsible for their care and control are exempt from having to be vaccinated. 

Contact your local veterinarian for more information about vaccination or to find out if your pet’s vaccinations are up-to-date. Pet owners can be fined if their pets are not routinely vaccinated.

For more general information, you can also visit Ontario’s Rabies in pets page.

Treating a possible exposure to rabies

Some people who have been bitten by an animal will be vaccinated against rabies. This is a decision a doctor will make with you.

What happens when an animal bites someone?

NWHU begins an investigation of every bite incident within 24 hours of notification. A public health inspector will collect information about the incident from you and the pet owner (if possible).

If tests determine that you have had exposure to a rabid animal, a Primary Care Provider will treat you with the vaccine.

What happens to the animal that bites a person?

If your pet was involved in biting a human, a Public Health Inspector will contact you and gather information such as:

  • Is the animal’s rabies vaccination up-to-date? 
  • Did the animal have contact with wild animals? 
  • Was the animal acting strangely, either very aggressive or very docile, unusual for that particular animal? 
  • Was the bite provoked?

From the time of exposure, it can take 10 days for symptoms to occur whether it is an animal or human. An animal that has bitten or scratched someone must be observed for 10 days following the incident to see if symptoms arise. If the dog shows no symptoms after 10 days, then it is not contagious for rabies.

For more information on rabies, call 1-800-830-5978 or email talkpublichealth@nwhu.on.ca.

Blastomycosis

Blastomycosis

Blastomycosis is an infection caused by a fungus, Blastomyces dermatitidis. Blastomycosis affects the lungs or skin. Pneumonia caused by the spores may present with fever, chills, cough, sore chest, weight loss, aches, and fatigue. Skin infections caused by the spores may begin with lesions on the face or extremities, starting out mild but progressing to crusty or open wounds. Weight loss, fever, and fatigue can also occur with these skin lesions.

There is no vaccine against Blastomycosis, and there is no environmental control product to get rid of it. You cannot see it, so avoiding it when it is present is difficult. Symptoms can start weeks or months after exposure, which also makes pinpointing the location of Blastomycosis difficult.

Preventing Blastomycosis

Although there is no evidence that proves personal protective equipment prevents infection from blastomycosis, when performing work that disturbs the soil, especially when your face will be near the soil you should consider wearing:

  • Work gloves 
  • Long pants and sleeves 
  • Enclosed footwear 
  • A dust mask 
  • Eye protection

Individuals with weakened immune systems should also consider avoiding exposure to disturbed soil, especially in moist, acidic areas.

What’s the risk of Blastomycosis in our area

Blastomycosis is much more common in northwestern Ontario than in other parts of Ontario. If you have been outdoors in NWO and develop symptoms as described, or if you are starting a medication that will lower your immune system, tell your doctor you may have been exposed to the fungus that can cause Blastomycosis. There are specific tests for a fungal infection that your doctor can arrange; for more information, visit our Blastomycosis Information for Health Care Providers page

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Last modified: 2 October 2023