title: Serological and molecular evidence for spotted fever group Rickettsia and Borrelia burgdorferi sensu lato co-infections in The Netherlands.
abstract: Only a few reported cases indicate that Rickettsia helvetica and Rickettsia monacensis can cause disease in humans. Exposure to these two spotted fever group (SFG) rickettsiae occurs through bites of Ixodes ricinus, also the primary vector of Lyme borreliosis in Europe. To date, it is unclear how often exposure to these two microorganisms results in infection or disease. We show that of all the Borrelia burgdorferi s.l.-positive ticks, 25% were co-infected with rickettsiae. Predominantly R. helvetica was detected while R. monacensis was only found in approximately 2% of the ticks. In addition, exposure to tick-borne pathogens was compared by serology in healthy blood donors, erythema migrans (EM)-patients, and patients suspected of Lyme neuroborreliosis (LNB). As could be expected, seroreactivity against B. burgdorferi sensu lato was lower in blood donors (6%) compared to EM patients (34%) and suspected LNB cases (64%). Interestingly, seroreactivity against SFG Rickettsia antigens was not detected in serum samples from blood donors (0%), but 6% of the EM patients and 21% of the LNB suspects showed anti-rickettsial antibodies. Finally, the presence of B. burgdorferi s.l. and Rickettsia spp. in cerebrospinal fluid samples of a large cohort of patients suspected of LNB (n=208) was investigated by PCR. DNA of B. burgdorferi s.l., R. helvetica and R. monacensis was detected in seventeen, four and one patient, respectively. In conclusion, our data show that B. burgdorferi s.l. and SFG rickettsiae co-infection occurs in Dutch I. ricinus and that Lyme borreliosis patients, or patients suspected of Lyme borreliosis, are indeed exposed to both tick-borne pathogens. Whether SFG rickettsiae actually cause disease, and whether co-infections alter the clinical course of Lyme borreliosis, is not clear from our data, and warrants further investigation.
authors.affiliation: Centre for Experimental and Molecular Medicine, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands. Electronic address: j.koetsveld@amc.nl.
authors.forename: Joris
authors.initials: J
authors.lastname: Koetsveld
authors.affiliation: Centre for Infectious Disease Control, Institute for Public Health and Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands. Electronic address: ellen.tijsseklasen@gmail.com.
authors.forename: Ellen
authors.initials: E
authors.lastname: Tijsse-Klasen
authors.affiliation: Centre for Infectious Disease Control, Institute for Public Health and Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands. Electronic address: tineke.johnston@casema.nl.
authors.forename: Tineke
authors.initials: T
authors.lastname: Herremans
authors.affiliation: Centre for Experimental and Molecular Medicine, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands. Electronic address: lyme@amc.nl.
authors.forename: Joppe W R
authors.initials: JW
authors.lastname: Hovius
authors.affiliation: Centre for Infectious Disease Control, Institute for Public Health and Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands. Electronic address: hein.sprong@rivm.nl.
authors.forename: Hein
authors.initials: H
authors.lastname: Sprong
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology; D001483:Base Sequence; D015748:Borrelia burgdorferi Group / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D060085:Coinfection; D005260:Female; D006801:Humans; D018884:Ixodes / Q000382:microbiology; D008193:Lyme Disease / Q000453:epidemiology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D012281:Rickettsia / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D012282:Rickettsia Infections / Q000453:epidemiology / Q000382:microbiology*; D016415:Sequence Alignment; D017282:Tick-Borne Diseases / Q000453:epidemiology / Q000382:microbiology*
keywords: Borrelia burgdorferi; Ixodes ricinus; Lyme borreliosis; Rickettsia helvetica; Rickettsia monacensis; co-Infection