Now’s the time to check for West Nile/Lyme disease

By MPP Toby Barrett

When new or relatively unknown disease advances, public health and disease treatment systems are often unprepared. I think of SARS in Toronto 11 years ago and the Ebola virus in West Africa today.

Over the past few years we have seen the arrival of two vector-borne diseases in southern Ontario – the mosquito-borne West Nile virus and the tick-borne Lyme disease. Again, public health has scrambled to respond, as have treatment systems, in many cases with less than satisfactory success. As mosquito and tick season draws to a close, those of us who spend time outdoors may want to reflect back on our time of possible exposure, and if we have spotted symptoms of infection.

Since West Nile is spread by mosquitoes, any prime mosquito habitat could be West Nile habitat. Mosquitoes like long grass and need standing water to breed. Most people infected with it will develop no symptoms. About 20 per cent will develop what is known as West Nile fever, with symptoms that include fever, headache, body ache, fatigue, back pain, skin rash and swollen nymph nodes. Less than one per cent will develop serious neurological symptoms.

Blacklegged ticks can carry Lyme disease and are commonly found along the north shores of Lake Erie, Lake Ontario and the St. Lawrence River in Ontario. Long Point and Turkey Point on Lake Erie were early hot spots. Called The Great Imitator, Lyme disease is often mistaken for the flu or common cold. Symptoms can include: fatigue, fever or chills, headache, numbness or tingling, spasms, skin rash, brain fog, dizziness, swollen nymph nodes, arthritis and arthritic symptoms and abnormal heartbeat.

Of the five reportable vector-borne diseases, West Nile virus and Lyme disease are the only ones that occur in Ontario and are of public health importance. There is limited mosquito surveillance on Eastern equine encephalitis virus (EEEV), while malaria and yellow fever are travel-related diseases with no endemic transmission reported in the province. For the year 2012, confirmed cases in Ontario were: West Nile virus – 239, malaria – 220, Lyme disease, including probable cases – 185, yellow fever – 2.

West Nile virus was first recognized in Africa in the 1930s. West Nile was first detected in Ontario in birds in 2001, with the first human cases following a year later. It became reportable in Ontario in 2003. During the mosquito season, Public Health Ontario produces weekly reports on the status of West Nile human cases, mosquitoes and horses in the province.

Technically speaking, Lyme disease is a tick-borne bacterial disease. The blacklegged ticks that transmit it are usually associated with deciduous or mixed forests. The identification and reporting of human Lyme cases is similar to West Nile virus cases.

Eastern equine encephalitis is also a mosquito-borne virus that circulates between birds and mosquitoes, with bridge vectors transferring the virus to humans and horses. To date, no cases have been reported in Ontario.

A few decades ago, vector-borne diseases were not a concern for Ontario residents. That has changed. They are here and an immediate threat. Education of the symptoms can minimize the threat and facilitate prompt treatment.

If you farm, fish, hunt, hike, bike, or spend a lot of time outdoors, keep an eye for any symptoms of these two relatively-new afflictions.

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