Mosquito Awareness: Wet Nile Virus

"A procession of specialists came to see me [in hospital], a neurologist and an infectious-disease specialist. I think I was their first specimen with the virus."
"I slept for long periods of time. I only became conscious when the pain from the needles in the IVs became too much to tolerate [in the treatment of the viral meningitis she was afflicted by resulting from a West Nile infection]."
"A mosquito bite can change your life."
Mary Sharina, 67, Ottawa resident

There has been an entry to countries that had never known the existence of some diseases thought of as being of exotic origin, common to warmer geographies than those of the northern portion of North America with the advent of climate change. A changing atmosphere where warmer temperatures reflect a warming world, means that creatures once unknown to any but tropical or subtropical zones now find themselves comfortable even where winter is cold and killing -- but no longer cold enough in a sustained way to dispatch mosquitoes, those of the Culex genus that carry West Nile virus.

West Nile doesn't yet rage through Ontario, but it has a presence, and has had for decades. Originally a bird virus, mosquitoes are now the vector for the virus, picking it up after stinging birds carrying the virus. Humans don't have much contact at close quarters with birds, but they certainly do, however involuntarily, with mosquitoes, pests that flourish during the summer months, as long as there is enough moisture to enable them to lay their eggs. Once public health agencies in Canada were alerted to the presence of West Nile, courtesy of mosquitoes, a public program commenced to spray sewer systems with a chemical agent meant to kill mosquito larvae.

Still, infections can occur, and do, albeit at a low level. Concerns about West Nile virus are not misplaced. An infection has the potential to cause encephalitis, meningitis, and other long-term health conditions that can even lead to death. On the hopeful side for many, most people who are infected may realize no symptoms whatever. When Ottawa, Ontario resident Mary Sharina in 2012 shared a glass of wine with a friend in her backyard, she recalls a mosquito bite. Days later she felt the occasional headache, and within weeks she had contracted viral meningitis, thanks to the virus she was diagnosed with.

Although the viral meningitis, once diagnosed, was treated allowing her to return home and resume her normal life, additional consequences over the years developed, the most serious of which was a heart condition, such that she required surgery. Two ablation procedures to treat abnormal heart rhythms were performed for her, to remove or destroy abnormal heart tissue to enable her heart to return to a normal heart rhythm. She was fortunate to have contracted viral meningitis, and not the bacterial variety, much more dangerous and potentially fatal without antibiotic treatment.

In 2013 four cases of West Nile were discovered in Ottawa, increasing to twenty cases by 2017. Symptoms are similar to those of the flu, and typically but not always include fever, frontal cranial headache, muscle aches -- occasionally accompanied by a skin rash. Symptoms can also include neck stiffness, muscle weakness and stupor. A public information campaign accompanies the spraying program every summer, alerting residents to the need to be aware that standing water on their property invites mosquitoes to breed and lay their eggs, making the residents vulnerable as a result.

Toronto Public Health confirmed the first human West Nile virus case in the city for 2018. But the conservation authority says the odds of residents contracting the disease is 'still fairly rare.' (James Gathany/Centers for Disease Control and Prevention/Associated Press)