News Releases

The Office of the Chief Medical Officer of Health is 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 and reducing exposure to mosquitoes when there is a risk for exposure to West Nile virus;

·         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 avoid E. coli infections;

·         vaccinate their pets and avoid handling wildlife to reduce the risk of rabies;

·         avoid exposure to dust from mice 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 (WNV)

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 2008 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.

 

People with pre-existing medical conditions and older adults are more at risk for severe illness.  However, severe illness has occurred in all age groups.

 

Of those who get infected, less than one per cent develop serious illness (West Nile neurological syndrome) including encephalitis, an inflammation of the brain.  Approximately 20 per cent develop West Nile virus non-neurological syndrome, an illness with symptoms such as fever, headache, fatigue and body aches.  Approximately 80 per cent of people infected with West Nile virus have no symptoms and do not become ill.

 

Human cases of West Nile virus were first identified in Manitoba in 2003.  In 2007, Manitoba reported 587 human cases, the highest number of human cases reported in one year. Of this total, 72 neurological cases were reported, including four deaths.

Based on mosquito surveillance data and risk assessments, 49 communities were larvicided and ministerial public health orders were issued for adult mosquito control in 19 communities in 2007, the most mosquito control used so far for West Nile virus.  In 2008, larviciding and adult mosquito control will continue to be used as needed, based on mosquito surveillance data and risk assessments.

 

As in previous years, the Office of the Chief Medical Officer of Health will continue to provide the public with information on the risk of West Nile virus through public education, weekly media updates and by posting information online throughout the summer of 2008.                                                                          

Lyme disease is a bacterial infection that people can get from the bite of an infected blacklegged (deer) tick.  Adult blacklegged ticks can be found from April to November but are most common in October and 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 three days to one month after a tick bite, often with an expanding ring-like rash which then fades.  Early symptoms can also include headache, stiff neck, fever, muscle aches or fatigue. 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.  Treatment should be based upon a clinical diagnosis as blood tests taken soon after infection may not show evidence of Lyme disease.  If untreated, additional health effects may develop including neurologic, cardiac or arthritic conditions. 

 

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.

 

Since 2005, five cases of Lyme disease have been identified in people who had visited the southeastern corner of Manitoba.  In 2006, Manitoba Health and the Public Health Agency of Canada carried out a field survey.  The survey found that a blacklegged tick population infected with the Lyme disease bacteria was established in this area.  Blacklegged ticks are also distributed by birds to locations throughout the province.

 

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.

 

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.

 

Since 1999, 19 cases of Lyme disease have been reported in Manitobans.  Sixteen cases have been reported in the last three years.  Seven of the cases were found in people who travelled to areas with established blacklegged tick populations outside of Manitoba. 

 

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.

 

To reduce the risk of illness, proper food-handling precautions should be taken to avoid exposure to undercooked ground beef or other foods or items that have been in contact with raw meat or sources of E. coli.  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.  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, especially if they are near to cattle. In addition, testing of wells should be done regularly.

 

In Manitoba, there are about 50 cases of E. coli infection reported each year.

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 2007. 

 

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 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 that the virus may become airborne, and

-        ensuring hand washing takes place after cleanup is complete. 

Blastomycosis is an infection caused by a fungus found in acidic, moist soil mainly in areas around the Great Lakes and Mississippi River including areas around the Manitoba-Ontario border. Infection can occur by breathing in the fungus or by getting it on a scrape or cut.