Lyme disease: 14% of the world’s population affected

Called by its scientific name infection Borrelia burgdorferi sensu lato, Lyme disease is a common infection transmitted by tick bites. It generates typical, localized redness and swelling of the skin, but the disease can spread to other tissues and organs, potentially affecting the nervous system, joints, heart and skin.

Learn about the disease

In order to better understand Lyme disease and determine the number of people affected, the authors of this work have combined data from 89 studies, involving 158,287 people.

Analysis of the pooled data revealed that the estimated overall seroprevalence, ie the presence of antibodies directed against the infection in the blood) reported by these various studies is 14.5%. The results are published in the journal BMJ Global Health.

Regions of the world more affected than others

Based on the findings of this meta-analysis, Central and Western Europe and East Asia are the regions of the world with the highest reported prevalence of infection. The least affected regions are the Caribbean, South Asia and Oceania.

Regarding the profile of the most exposed people, these are men aged 50 and over who live in rural areas. The authors further note that their resultsindicate that the prevalence of Lyme disease in 2010-2021 was higher than that of 2001-2010″.

However, they remain cautious in their conclusions because there are few long-term studies and it is not possible to know whether the presence of antibodies can have an effect on the risk of developing Lyme disease in the long term.

Climate change involved?

To understand why certain regions of the world are more prone to Lyme disease than others, researchers put forward possible explanations such as ecological and climatic changes, which include longer summers and warmer winters, lower precipitation, animal migration, fragmentation of arable land and more time spent outdoors with pets.

A poorly understood disease

What the authors of this work point out is that Lyme disease, “although it is widespread, it has not received much attention in the world”.

An observation shared by Bertrand Pasquet, president of ChroniLyme, an association of patients affected by the disease: “This study proves that it is essential, in France and around the world, to massively fund medical research to understand why some individuals do not develop any symptoms while others will develop, on the contrary, severe and persistent forms that are often disabling and which defeat medicine. It is obvious that we are not equal in the face of tick-borne diseases and looking to the side of the immune system is the direction to follow. Why are these joint damage, heart damage and neurological damage so violent in some people? he wonders.

The authors of this study hope that their work will “inform the development of public health response policies and disease control programs”.