Manitoba public health officials are encouraging Manitobans to take advantage of spring and summer by enjoying outdoor activities, increasing physical activity and improving their health.
However, Manitobans are reminded that exposure to some infectious diseases occurs through contact with the environment, more often in the spring and summer. These diseases include West Nile virus, Lyme disease, E. coli infections, rabies, hantavirus and blastomycosis.
Manitobans can take precautions to reduce the risk of these diseases. People can:
• prepare for West Nile virus season by reducing standing water around their homes;
• take precautions to avoid contact with blacklegged (deer) ticks to reduce their risk of Lyme disease;
• take proper food-handling precautions and test wells regularly to reduce food- and water-borne infections;
• vaccinate pets and avoid handling wildlife to reduce the risk of rabies;
• avoid exposure to mouse droppings to reduce the risk of hantavirus infections; and
• be aware of the risk for exposure to blastomycosis from fungal spores found in soil in the risk areas.
West Nile virus
Mosquitoes are just starting to appear. At this time, the risk of being bitten by a mosquito carrying West Nile virus is considered very low but this risk will increase as the weather gets warmer. The majority of the mosquitoes that are active at this time of year are not Culex tarsalis, the main species known to carry West Nile virus in Manitoba.
The 2009 mosquito surveillance program for West Nile virus will begin this weekend.
Manitobans can prepare for mosquito season by reducing standing water around their homes, which helps prevent the development of Culex tarsalis mosquitoes. This includes:
• cleaning eavestroughs and regularly emptying bird baths and other items that might collect water,
• ensuring rain barrels are covered with mosquito screening or are tightly sealed around the downspout,
• clearing yards of old tires or other items that collect water, and
• improving landscaping to prevent standing water around the home.
The risk of exposure to this virus varies from year to year. Human exposure has occurred from June to September, with most exposures occurring in July and August. During these times, Manitobans can reduce the risk of mosquito bites by:
• reducing the amount of time spent outdoors between dusk and dawn;
• using appropriate mosquito repellent;
• wearing light-coloured, loose-fitting clothing; and
• maintaining door and window screens so they fit tightly and are free of holes.
Human cases of West Nile virus were first identified in Manitoba in 2003. In 2008, Manitoba reported 12 human cases. Of this total, two neurological cases were reported. In 2007, Manitoba reported a total of 587 human cases, with 72 neurological cases including four deaths.
Manitoba Health and Healthy Living will continue to provide the public with information on the risk of West Nile virus through public education, media updates and by posting information online throughout the summer.
More information about West Nile virus is available by visiting the Manitoba Health website at www.gov.mb.ca/health/wnv.
Lyme disease
Lyme disease is a bacterial infection that people can get from the bite of an infected blacklegged (deer) tick. Blacklegged ticks can be found from April to November. These ticks are smaller in size than the common dog (wood) tick, which does not transmit Lyme disease.
Symptoms of Lyme disease can start about two days to one month after a tick bite, often but not always with an expanding ring-like rash which then fades. Early symptoms can also include headache, stiff neck, fever, muscle aches or fatigue. Sometimes Lyme disease can be difficult to diagnose because some of the symptoms are common to many other diseases and individuals may not realize they have been bitten by a tick.
People who think they may have Lyme disease should see their doctor. Lyme disease can be successfully treated with antibiotics and treatment is most successful in the early stages of infection.
Throughout Manitoba, there is a chance of being exposed to Lyme disease through contact with infected blacklegged ticks deposited by birds. However, there is a much greater risk in the southeast corner of the province where an infected blacklegged tick population is established.
Manitobans can reduce their contact with blacklegged ticks by:
• avoiding tick-infested areas whenever possible including limiting contact with tall grass or wooded areas and staying to the centre of hiking trails or paths;
• wearing light-coloured clothing to make it easier to see ticks that may be on you;
• wearing long pants and a long-sleeved shirt if you are in tall-grass habitats or wooded areas where ticks are most commonly found;
• tucking your shirt into your pants and your pants into your socks to prevent ticks from attaching to your skin;
• using repellents containing DEET on clothing and exposed skin after reading and closely following instructions for use, especially when applying repellent to children;
• inspecting yourself, children and pets for ticks and removing them as soon as possible; and
• keeping grass well mowed on property to help reduce the amount of habitat suitable for ticks.
The risk of catching Lyme disease from a blacklegged tick is reduced if it is removed early, especially within 24 hours. If a tick is attached to skin, carefully remove it with tweezers. Grasp the tick close to the skin and pull slowly upward with steady pressure. Avoid twisting or crushing the tick. Cleanse the skin around the tick bite with soap and water or a disinfectant. Mark the date and location of the bite on your calendar.
Further information on Lyme disease is available from Manitoba Health and Healthy Living.
E. coli infection (hamburger disease) and other food and water-borne infections
Hamburger disease results from infection with a specific strain of E. coli bacteria. The most commonly reported source of this infection in Manitoba is contaminated ground beef that has been improperly handled or prepared. Other potential sources of this infection can include contaminated well water or person-to-person contact. Symptoms start from two to 10 days after exposure and most commonly include watery diarrhea that may become bloody. There may also be cramps, vomiting and mild fever. Severe cases can result in kidney failure or death.
In Manitoba, there are about 75 cases of E. coli infection reported each year. To reduce the risk of illness due to E.coli or other food-borne infections, proper food-handling precautions should be taken to avoid exposure to undercooked meat or other foods or items that have been in contact with raw meat. It is important to thoroughly wash all utensils, dishes, cutting boards and countertops that have come in contact with raw meat. Cook ground beef until it is well done and follow guidelines for cooking other meat. Refrigerate or freeze meat as soon as possible after buying and always wash hands after handling raw meat.
To lower the risk of illnesses that can be caused by contaminated water, well users should check that their well is safe from sources of contamination. Well testing should be done regularly. For more information about well water safety, visit the website.
Information on hamburger disease is available at:
www.gov.mb.ca/health/publichealth/ecolifs.html.
More information about safe food handling can be found at:
www.inspection.gc.ca/english/fssa/concen/tipcon/thermoe.shtml or
www.gov.mb.ca/agriculture/foodsafety/consumer/cfs01s04.html.
Rabies
Rabies is a disease caused by a virus carried in the saliva of an infected animal. Rabies is spread when infected animal saliva gets under the skin (usually by a bite) or on the mucous membranes such as the lining of the mouth, nose or eyes.
Wild animals that are most likely to carry rabies include bats, skunks, raccoons and foxes. Domestic animals, particularly dogs and cats, and farm animals such as horses and cows can get rabies from contact with infected animals.
Vaccination and rabies-immune globulin given shortly after a bite can prevent the development of rabies, which is otherwise usually fatal. Each year, rabid animals are identified in the province and human exposures treated. However, human cases of rabies are rare and no cases were reported in Manitoba in 2008.
Manitobans can reduce the risk of rabies by vaccinating pets and avoiding handling wildlife. Individuals who have been bitten by domestic or wild animals should see their health-care provider or contact Health Links–Info Santé for advice on wound care and rabies risk.
Hantavirus
Hantavirus infection is a rare viral disease which can be fatal. In Manitoba, the virus is found in urine, feces and saliva of infected deer mice. There have been three human cases reported in Manitoba since 1999 including two deaths. The most recent case was reported in 2007. Hantavirus infection usually occurs when people breathe in the air-borne virus. This exposure usually occurs in enclosed spaces. Symptoms usually develop a few weeks after exposure. Initial symptoms are flu-like including fever, muscle aches and abdominal pain, which can be followed by shortness of breath.
People can take precautions to prevent exposure to hantavirus by:
• rodent-proofing buildings,
• airing out enclosed areas as much as possible before entering, and
• taking precautions during cleanup of areas that may be contaminated with the virus including:
• wearing gloves and appropriate masks,
• dampening areas contaminated with rodent droppings with bleach disinfectant and removing droppings with a damp mop or cloth to reduce the chance the virus may become airborne, and
• ensuring hand washing takes place after cleanup is complete.
Blastomycosis
Blastomycosis is an infection caused by a fungus found in acidic, moist soil mainly in areas around the Great Lakes and Mississippi River, northwestern Ontario and areas around the Manitoba-Ontario border. Infection can occur by breathing in the fungus or by getting it on a scrape or cut.
Symptoms can include cough, muscle aches, joint pain, fever, chills, tiredness or skin infections. Symptoms often appear gradually weeks or months after exposure. It is not a common disease, which can make diagnosis difficult. People experiencing these symptoms should see a doctor and are encouraged to tell a doctor if they have travelled to an area where blastomycosis fungi are found to help in the diagnosis.
Blastomycosis is not passed by animals to humans or from person-to-person. It can be effectively treated with specific anti-fungal medication.
Although there is little evidence of effectiveness, people can take precautions including wearing gloves and other protective clothing, and using a dust mask when working in areas where the fungus may exist.
Since blastomycosis became reportable in Manitoba in 2006, 43 cases have been reported to Manitoba Health and Healthy Living.
More information on blastomycosis, hantavirus and rabies is available from local public health offices or from Manitoba Health and Healthy Living fact sheets available online.
For additional information, Manitobans can also visit their local public health office or phone Health Links–Info Santé at 788-8200 or toll-free at 1-888-315-9257.
