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Bitten by a tick, a 9-year-old boy was affected by the Powassan virus. Little known, this infection is nevertheless fatal in some cases. Zoom in on this fearsome virus, the countries affected and the means to protect yourself from it.
Two months ago, a 9-year-old boy was admitted to a hospital in Ottawa, Canada, with symptoms including fever, stiff neck and headache. The symptoms came on after he went camping in northern Ontario. It took several weeks and numerous tests for doctors to diagnose the boy with Powassan virus. A study published in the Canadian medical association journal (CMAJ) concerns this rare case.
A virus transmitted by ticks
The Powassan virus was first discovered in 1958 in Ontario. It is an arbovirus, and more precisely a flavivirus, which is therefore transmitted to humans by infected ticks (Ixodes cookei, Ixodes marxi, Ixodes spinipalpus). If bitten, the infection spreads after just fifteen minutes.
Humans are not the only potential hosts, as deer, foxes, marmots, hares, raccoons, skunks, domestic dogs and cats can also be carriers. It has so far only been detected in the United States, Canada and Russia.
A disease with potentially serious consequences
The incubation period for the infection is approximately one to five weeks. The infected person will then present flu-like symptoms for a few days: fever, headaches, vomiting, muscle weakness followed by mental confusion, epileptic seizures, memory loss, etc. If this infection worries researchers, it is because infected patients can develop serious neurological problems such as viral encephalitis (inflammation of the brain) or transverse myelitis (inflammation of the spinal cord).
Current data suggest that approximately 10 to 15 percent of people with severe disease die. Among those with neurological problems related to Powassan disease, there is a 50 percent chance of persistent neurological deficits, including altered mental status and cognitive difficulties.
A lack of clinical recognition
Although cases of infection remain rare, scientists denounce the lack of knowledge of the disease by doctors, which can lead to an underestimation of the incidence. Over the last twenty years, there has been an increase in cases of encephalitis linked to the Powassan virus and other tick-borne diseases. However, there is still no treatment or vaccine to date for this virus.
The authors of the study call for vigilance, recommending in particular that specialists carry out a broad-spectrum test in the event of symptoms of encephalitis in a patient, particularly in summer and autumn.
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