A mild November has seen a steep rise in the number of tick-tests being requested in one Canadian province, with similar increases likely in other areas that have also experienced warmer days and nights in recent weeks. This mild weather extends the tick season and means that more people are exposed to bites from ticks carrying the Lyme disease bacteria. Testing such ticks can help give an indication of the presence of the infection in a tick population and help officials give guidance on the likelihood of Lyme disease occurring.
Exposure to Infected Ticks
In Brockville, Ontario, 568 ticks have been submitted for testing at the local health unit, with 40 testing positive for Borrelia burgdorferi so far, and another 271 tests still to be carried out. Most of the remaining ticks were submitted for testing after mid-October and in November this year, which is unusual given the normal winding down of ticks’ activity in fall. The mild weather also means that local residents have been enjoying more time outside in areas where ticks are present when they might, in colder years, be wrapped up warm inside their homes.
Average Tick Infection Rates
The increased number of ticks found to be infected with Lyme disease bacteria appears to be proportional to the overall increase in ticks submitted for testing. The positive tests so far amount to 7% of the ticks tested with the rate of infection found to be 8% of the 382 ticks tested in the whole of 2010. Clearly, the number could rise, or the average could fall once the other 271 ticks are tested. Health officials are being positive about the increase in the number of ticks submitted, seeing it as a sign that Lyme disease awareness is spreading throughout the local population, hopefully increasing vigilance and the implementation of Lyme disease prevention techniques by residents.
Monitoring Tick Populations
The health unit is also carrying out its own geographical analysis of the ticks submitted in order to see if there are any tick populations not currently on their radar. People submitting ticks for testing are not only asked where they live but also whether they have spent any time camping or hiking in other areas so as to identify possible tick enclaves that could create Lyme disease outbreaks. There is also a call for increased Lyme disease education to further supplement that work already being done. It is unknown if the public health authorities are testing for other bacteria, such as common co-infections with Lyme disease, or just running PCR tests for the DNA of Borrelia burgdorferi. Should an increase in the rate of tick infection be found in this area it may prompt other health units nearby to increase their own testing programmes and possibly encourage increased research into Lyme disease tests for patients themselves. Using PCR tests on patients is an unreliable indicator of active Lyme disease infection and the Public Health Agency of Canada does not currently have a good reputation with patients looking for positive and proactive Lyme disease case management.
Increases in Lyme Disease Cases
Lyme disease does seem to be on the increase in both the US and Canada however and Alberta recently issued a public health announcement stating that the infection had been found in patients in the province. The highest incidence of reported Lyme disease cases still occurs in the northeast of the US, from Massachusetts to New York, along with north-central regions and now into the Pacific Northwest. Southern cases of Lyme disease are still considered relatively rare but some university professors and doctors have taken it upon themselves to collect ticks for testing in order to identify the real risks of Lyme disease in many states.
Submitting Ticks for Testing
In Canada there have been a variety of tick species reported, but the blacklegged tick is the only one that public health authorities recognize as capable of transmitting Lyme disease. Southern and eastern Ontario, parts of Nova Scotia, portions of Vancouver Island and the lower Fraser Valley, along with parts of southeastern Manitoba have established tick populations known to be infected with Lyme disease. Alberta has recently joined that group according to local health officials. Ticks in Canada have been studied by the PHAC since the 1990s and details of how to collect ticks for testing and where to submit them can be found at the PHAC website. The local health agency will determine if the tick is a blacklegged tick and only then will it be submitted to the national microbiology laboratory for testing.
Other tick-tests, including home tick-tests, are available but patients should understand that even if a tick is found to be infected with Lyme disease bacteria this does not mean that the person from whom the tick was removed has also been infected. Similarly, a negative tick-test result could mean that the person is uninfected but it may be that they were bitten by more than one tick at the same time and that bacterial transmission happened through an unobserved bite. Monitoring for symptoms and keeping a record of anything abnormal can help identify the disease at a later stage. Tick-testing is an important part of Lyme disease prevention but raising awareness of the condition is also key to reducing its incidence.
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