Cases of Lyme disease rebound in Quebec after 2020 slowdown

Lyme disease in Quebec was back on the rise in 2021, following a brief slowdown in 2020.

According to data released earlier this week by Quebec's public health institute (INSPQ), 709 cases of Lyme disease were reported to provincial health authorities as of April 6, 2022. Of those infections, 650 were likely acquired in Quebec, while the rest occurred elsewhere.

The rate of the disease in 2021 was 1.7 times higher than in 2019, the year with the second-highest recorded rate.

Of the 650 cases of Lyme disease acquired in Quebec, Estrie was again the most affected region. With 452 cases, it accounts for nearly 70 per cent of all infections in Quebec.

Authorities reported 124 cases in Montérégie.

The other regions, including Montreal, reported fewer than 20 cases.

The age group most affected by Lyme disease in Quebec in 2021 was 60-69, followed by 50-59, 40-49 and 70-79.

Lyme is transmitted through the bite of a tick carrying the disease.

The tell-tale symptom in humans is a reddening of the skin. Many with the disease experience fatigue, fever, aches and pains -- and if the disease isn't detected and treated quickly, the bacteria can disperse into the bloodstream, leading to much more uncomfortable symptoms.

According to the Quebec government, milder winters could partly explain the disease's progression. The warmer climate allows ticks to survive and reproduce more easily.

Lyme disease has been a notifiable disease in Quebec since 2003, meaning doctors and laboratory technicians who detect a case must inform public health authorities. 

This report by The Canadian Press was first published in French on June 9, 2023.