Here are the specific published studies and systematic reviews where those percentages were reported:
Germany (30%), Greece (19.8%), Poland (25.8%), And Slovakia (23.5% / 24.8%)
These rates were aggregated and published in a 2021 study examining the baseline seropositivity of healthy adults in various European nations, alongside original data from Eastern Slovakia.
Reference: Seroprevalence of Bartonella henselae and Bartonella quintana Infection and Impact of Related Risk Factors in People from Eastern Slovakia. Published in the journal Pathogens (MDPI), September 2021.
Poland (46.4% In High-Exposure Areas)
This higher capture rate was documented in a very recent study tracking multiple tick-borne seroprevalences specifically in the human population of Eastern Poland.
Reference: Seroprevalence of Borrelia, Anaplasma, Bartonella, Toxoplasma, Mycoplasma, Yersinia, and Chlamydia in Human Population from Eastern Poland. Published in the journal Pathogens (MDPI), January 2025.
Spain (13.5% B. henselae / 11% B. quintana)
Data resulting from a large human serologic study tracking community exposure in the southern region of the country.
Reference: Serologic study of Bartonella sp. infection among human population of Southern Spain. Published in Enfermedades Infecciosas y Microbiología Clínica (Elsevier), April 2022.
China (~14% Healthy Donors / 27% Dog Bites)
This study explicitly compared standard, healthy blood donors against patients presenting to clinics for dog and animal bites, demonstrating the elevated risk boundary.
Reference: Seroprevalence of Bartonella henselae and Identification of Risk Factors in China. Published in Biomedical and Environmental Sciences, 2020 (and cited in the current Medscape epidemiological textbook for Bartonellosis).
United States (15% To 33% In Lyme Patients)
This data specifically tracked the overlap of Bartonella seropositivity in patients who were already diagnosed with Lyme disease, highlighting its prevalence as a coinfection rather than standalone general population exposure.
Reference: Human Bartonellosis: An Underappreciated Public Health Problem? Published in Tropical Medicine and Infectious Disease (available via NIH PMC), 2019.
Eastern Mediterranean Region (13.7%)
A massive systematic review and meta-analysis of epidemiological data spanning World Health Organization datasets for the entire region to aggregate total human and animal seropositivity.
Reference: Bartonellosis in World Health Organization Eastern Mediterranean Region: a systematic review and meta-analysis. Published in BMC Infectious Diseases (available via NIH PMC), January 2025.