March 19, 2012

LYME DISEASE UPDATE

– – –
Established Blacklegged Tick Populations Identified in Manitoba

Manitoba Health advises that more blacklegged tick populations have been identified in the province. There are now several areas across southern Manitoba where populations of blacklegged ticks are confirmed or suspected to be established.
Blacklegged ticks can carry the bacteria that causes Lyme disease.  Manitobans are advised to watch for ticks in southern areas of the province, particularly where established blacklegged tick populations have been identified and also in areas with suitable tick habitats.
Manitobans can take the following precautions to reduce the risk of coming into contact with blacklegged ticks while enjoying the outdoors:

• limit contact with tall grass or other vegetation along wooded areas and stay to the centre of hiking trails or paths;
• wear light-coloured clothing to make it easier to see ticks that may be on the skin or clothing;
• wear long pants and a long-sleeved shirt in tall-grass habitats or wooded areas where ticks are most commonly found;
• tuck a shirt into pants and pants into socks to prevent ticks from attaching to the skin;
• apply an appropriate repellent (it should say ‘tick repellent’ on the container) on clothing and exposed skin after reading and following instructions for use;
• inspect yourself, children and pets for ticks and remove them as soon as possible; and
• keep grass well mowed to help reduce the amount of habitat suitable for ticks.

Symptoms of Lyme disease can start about three days to one month after a tick bite, often with an expanding circular rash around the site of the bite, which then fades.  Early symptoms can also include headache, stiff neck, fever, muscle aches or fatigue, chills and swollen lymph nodes.  People who think they may have Lyme disease should see their doctor.  Lyme disease can be successfully treated with antibiotics.  Treatment is most successful in the early stages of infection. 

Established areas of blacklegged tick populations in Manitoba include:

• the southeast corner of Manitoba (confirmed in 2006);
• the area around the Stanley Trail in south-central Manitoba west of the Red River (confirmed in 2011 and extended north along the Thompson trail in 2012); and
• the area in and near Pembina Valley Provincial Park near the United States border (confirmed in 2012).

Areas with suspected established blacklegged tick populations include:

• the Pembina Valley to the north and west of Pembina Valley Provincial Park near La Rivière and roads 22N and 57W;
• Beaudry Provincial Park west of Headingley;
• the area around St. Malo in south-central Manitoba; and
• the area around Arbakka in south-central Manitoba.

A map showing the locations of confirmed and suspected established populations of blacklegged ticks is available on the Manitoba Health website at www.gov.mb.ca/health/lyme/surveillance.html.
Blacklegged ticks can be found in wooded areas, along streams and river banks, or along the edges of forest and prairie habitats with woody shrubs and other vegetation, plenty of leaf litter and high humidity.  The greatest risk of tick exposure occurs in the areas of the province identified with established or suspected established blacklegged tick populations.  Surveillance efforts in similar habitats are occurring in other areas.  Manitobans should consider tick precautions in areas of southern Manitoba with similar tick habitats.
In addition, blacklegged ticks can be deposited by birds outside of these areas.  Blacklegged ticks have been found throughout southern Manitoba and occasionally in the north.  Approximately 300 blacklegged ticks were submitted in 2011 in the fall tick-submission campaign.
Since 2009, 28 human cases of confirmed and probable Lyme disease have been identified in Manitoba.  The most likely locations of exposure were:

• seven cases in areas outside Manitoba;
• 12 cases in areas with established tick populations in Manitoba; and
• four cases in other areas of Manitoba.

It was not possible to determine the exposure location for five reported cases.

Approximately 10 per cent of the blacklegged ticks submitted to Manitoba Health were infected with the bacteria that causes Human granulocytic anaplasmosis (HGA).  In most cases, HGA is a mild illness.   Some people can get seriously ill, particularly people who are immune compromised or have other health conditions affecting the immune system.  Rare severe complications can include respiratory or kidney problems, encephalitis or meningitis, blood clotting disorders and occasionally death.
The symptoms of HGA can include fever, chills, headache, muscle aches and nausea.  Less frequent symptoms can include vomiting, diarrhea, loss of appetite, abdominal pain, joint pain, cough, confusion and occasionally a rash.  Symptoms can begin five days to three weeks after being bitten by an infected tick.
If you think that you may have HGA, contact your health-care provider.  HGA can be successfully treated with antibiotics.  Early diagnosis and treatment can reduce the time the person is ill and the severity of disease. 
At this time, no cases of Lyme disease have been reported in Manitoba in 2012.  In 2011, Manitoba had seven confirmed case of Lyme disease and four probable cases.  Four additional reports not meeting the national surveillance case definition were also received.  The definition for confirmed and probable cases for surveillance purposes is more stringent than clinical criteria used by physicians to consider treatment for Lyme disease.

This information is being presented at the Lyme Disease Scientific Symposium being held in Winnipeg today.  Medical and research experts from across North America have gathered to present current knowledge and emerging information on Lyme disease to health-care providers and researchers from across Canada.                                     
More information on Lyme disease and HGA is available at the Manitoba Health website at www.gov.mb.ca/health/lymeand www.gov.mb.ca/health/publichealth/environmentalhealth/hga.html, or by contacting Health Links-Info Santé at 204-788-8200 (in Winnipeg) or 1‑888-315-9257 (toll-free).

- 30 -