Coexistence of Ehrlichia phagocytophila and Borrelia burgdorferi sensu lato in Ixodes ricinus ticks from Italy as determined by 16S rRNA gene sequencing

• Published in: Journal of clinical microbiology Vol. 35; no. 12; pp. 3365 - 3366
• Main Authors: Cinco, M, Padovan, D, Murgia, R, Maroli, M, Frusteri, L, Heldtander, M, Johansson, K.E, Engvall, E.O
• Format: Journal Article
• Language: English
• Published: United States 01.12.1997
• Subjects: animal diseases; animal parasites and pests; Animals; Arachnid Vectors; Arachnid Vectors - microbiology; arthropod pests; bacterial infections; BORRELIA BURGDORFERI; Borrelia burgdorferi Group; Borrelia burgdorferi Group - genetics; Borrelia burgdorferi Group - isolation & purification; DNA, Bacterial; DNA, Bacterial - genetics; DNA, Bacterial - isolation & purification; EHRLICHIA; Ehrlichia - genetics; Ehrlichia - isolation & purification; Ehrlichiosis; Ehrlichiosis - transmission; Genes, Bacterial; genetics; human health and safety; Humans; isolation & purification; Italy; Ixodes; Ixodes - microbiology; Lyme Disease; Lyme Disease - transmission; medicine; microbiology; Polymerase Chain Reaction; RNA, Bacterial; RNA, Bacterial - genetics; RNA, Ribosomal, 16S; RNA, Ribosomal, 16S - genetics; transmission; Italy
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/JCM.35.12.3365-3366.1997

Human ehrlichiosis is a newly recognized rickettsial disease, first described in 1986 in the United States. The first European case of ehrlichiosis, diagnosed on a serological and clinical basis, was reported in Portugal in 1991. Furthermore, serological surveys recently conducted in Switzerland and the United Kingdom have shown the presence of antibodies to Ehrlichia phagocytophila in 5 to 7% of subjects bitten by ticks. Recently, a case of human granulocytic ehrlichiosis (HGE) infection was reported in Slovenia. The species involved in animal ehrlichiosis in Europe are E. canis, a monocytic ehrlichia, and granulocytic ehrlichiae of the E. phagocytophila genogroup. The vectors for ehrlichiae have been identified as Rhipicephalus sanguineus for E. canis and Ixodes ricinus for E. phagocytophila. Some work, based on PCR, on the detection of granulocytic ehrlichiae in Swedish ticks has been done, and indeed, a 16S rRNA gene sequence identical to that of the HGE agent has been found in one tick. However, on the whole, very little is known about the animal reservoir and the ecology of ehrlichiae throughout Europe. It has been supposed, on the basis of the coexistence of antibodies to tick-borne pathogens of ehrlichiosis and Lyme borreliosis (LB) in human sera, that the same ixodid ticks can be coinfected by Borrelia burgdorferi and Ehrlichia. Furthermore, the geographic distribution of HGE in the United States usually overlaps that of LB in those territories where the same ticks are present. In Italy Ehrlichia infections are present in dogs (E. canis) and horses, but neither human cases of clinically documented HGE nor any evidence of the organism in vector ticks has been reported. Since our investigations deal with the detection of B. burgdorferi in I. ricinus, in different areas of Italy, we looked for the presence of Ehrlichia in samples of ticks collected in an area of central Italy, where a certain prevalence of B. burgdorferi infection was detected.