More than 14% of the world’s population is likely to have – or had – Lyme disease, according to an analysis published today.
Lyme disease is the most common type of tick-borne infection, with highest prevalence in Central and Western Europe and Eastern Asia. Men aged 50 and over who live in rural areas are at most risk.
Researchers at The Institute for Tropical Medicine and the Yunnan Province Key Laboratory for Tropical Infectious Diseases in Universities, both at Kunming Medical University, China, searched major research databases and reviewed 137 eligible studies out of an initial haul of 4196, published up to the end of 2021. They then pooled the data from 89 studies, involving 158,287 people.
Writing in *BMJ Global Health*, the authors say their pooled data analysis reveals the reported estimated overall global seroprevalence – presence of antibodies to Bb infection in the blood – was 14.5%.
The three regions of highest reported seroprevalence were Central Europe at 21%, Eastern Asia at 16% and Western Europe at 13.5%. The regions with the lowest reported seroprevalence were the Caribbean (2%), Southern Asia (3%), and Oceania (nearly 5.5%).
The reported pooled Bb seroprevalence in studies that used Western blotting, which is an analytical technique to confirm the presence of specific proteins, was lower than that of studies using other confirmatory methods.
The smaller pooled analysis of 58 studies that used Western blotting showed that men aged 50 and over who lived in rural areas and who had been bitten by a tick were all associated with a heightened risk of Bb antibodies.
The authors suggest that the routine use of Western blotting could significantly improve the accuracy of Bb antibody detection.
“Our results indicate that the prevalence of Bb in 2010–2021 was higher than that in 2001–2010,” they write.
This could be down to issues such as ecological changes and factors including longer summers and warmer winters, lower rainfall, animal migration, and fragmentation of arable land.
The authors say there are limitations to their findings, including the scarcity of long-term studies, adding that it was impossible to systematically assess if Bb antibody positivity might have any long-term effect on the risk of developing Lyme disease or the risk of recurrence.
They also say the design of the included studies varied considerably, and most of the reports lacked important information, such as exact definitions of high risk groups.
Nevertheless, they conclude: “The reported estimated global Bb seropositivity is relatively high….[Lyme disease] is a widely distributed infectious disease, but it has not received much attention worldwide.”
Dong Y, Zhou G, Cao W et al. Global seroprevalence and sociodemographic characteristics of Borrelia burgdorferi sensu lato in human populations: a systematic review and meta-analysis. *BMJ Global Health* 14 June 2022. doi 10.1136/bmjgh-2021-007744
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