More than 14% of the world’s population has had Lyme disease, the most common tick-borne disease, according to a meta-analysis, which compiles studies on the subject.
Lyme borreliosis, or Lyme disease, is an infectious disease caused by a bacterium of the Borrelia burgdorferi sensu lato complex transmitted to humans through bites of infected ticks. According to the research published in the journal BMJ Global Health, Central Europe has the highest infection rate at 20%. Men over the age of 50 living in rural areas are most at risk.
Infection rates in Belgium have remained relatively stable over the past few years with statistics from the Public Health Ministry showing that on average around one thousand Belgians a year are diagnosed with Lyme disease. However, all indications suggest that the actual number of infections is much higher than first thought.
To show how common Lyme disease is around the world, the researchers identified 137 eligible studies (out of 4,196 possible) and pooled data from 89 of them.
In 14.5% of the approximately 160,000 participants in total, antibodies to the bacterium Borrelia burgdorferi (Bb) were found in the blood. “This is the most comprehensive and up-to-date systematic review of the global seroprevalence of Bb,” the study stated.
After Central Europe, the regions with the highest antibody levels are East Asia with 15.9%, Western Europe with 13.5% and Eastern Europe with 10.4%. The Caribbean has the lowest rate, at only 2%.
Previous research had shown that the prevalence of tick-borne diseases had doubled in the past 12 years.
According to the study, this increase is explained by longer and drier summers due to climate change, animal migration and “increasingly frequent contact with pets.” Farmers and other workers who regularly interact with host animals like dogs and sheep are most at risk of being bitten by an infected tick.
Data could be skewed in areas where Lyme disease is endemic because health authorities are more likely to perform regular antibody tests there compared to areas where it is less common, the study added.
Lyme disease is rarely fatal, but people bitten by an infected tick often have a rash and suffer from flu-like symptoms, including muscle and joint pain, headache, nausea and vomiting.