Prevalence and clinical manifestation of Borrelia miyamotoi in Ixodes ticks and humans in the northern hemisphere: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of observational studies (graded by design analogy)
PubMed 36113496 · doi:10.1016/S2666-5247(22)00157-4
What was done
The authors performed a systematic review and meta-analysis across PubMed and Web of Science (up to March 1, 2021) and reference lists to evaluate Borrelia miyamotoi prevalence in northern hemisphere Ixodes ticks (from 2011 onward) and humans (no date limit). Using random-effects models, they calculated pooled proportions and 95% CIs for tick infection rates, human seroprevalences, and PCR positivity rates across risk and clinical subgroups.
What was found
Across 157 included studies (165,637 ticks, 45,608 unique individuals, 504 human disease cases): - Tick infection prevalence was 0.7% (95% CI 0.6–0.8) in Ixodes pacificus and reached 2.8% (95% CI 2.4–3.1) in Ixodes persulcatus. - Overall human seroprevalence was 4.4% (95% CI 2.8–6.3), which was significantly higher (p < 0.0001) in high-risk individuals (4.6%, 2.6–7.1), participants with confirmed/suspected Lyme borreliosis (4.8%, 1.8–8.8), and those suspected of another tick-borne disease (11.9%, 5.6–19.9) compared to healthy controls (1.3%, 0.4–2.8). - PCR positivity was significantly higher in individuals suspected of another tick-borne disease than in the high-risk group (p = 0.025), with higher odds in Asia than in the USA (OR 14.63, 95% CI 2.80–76.41).
Why it matters
This meta-analysis provides benchmark prevalence figures in vector ticks and human populations across the northern hemisphere, underscoring B miyamotoi as a relevant differential diagnosis for patients presenting with suspected tick-borne illness.
Limits
Synthesized studies were observational with potential variation in serologic assays, cutoffs, and patient selection criteria. Tick literature was limited to studies published after 2010, and specific clinical symptom profiles were not reported in the abstract.
Cited by
- partial Hard tick relapsing fever Borrelia, such as Borrelia miyamotoi, is found in 25% of chronically ill Lyme-like patients.