Determination of NovelBorreliaGenospecies in SwedishIxodes ricinusTicks

Abstract

A total of 301 adult questing Ixodes ricinus ticks were collected at 15 different locations along the south and east coasts of Sweden to determine the Borrelia genospecies diversity. Thirty-two ticks (11%) were found to be positive by nested PCR with Borrelia burgdorferi sensu lato-specific primers. Species determination was based on partial sequencing of the 16S rRNA gene and the flagellin gene. Five different Borrelia species were found. The nucleotide sequence of the Borrelia DNA found in two ticks differed extensively from the nucleotide sequences of the Borrelia DNA found in the other ticks, and analysis revealed that they were closely related to the relapsing fever borrelia species Borrelia miyamotoi. This is the first report of a B. miyamotoi-like borrelia in I. ricinus and in Europe. Moreover, the Borrelia DNA of two ticks (6%) clustered within the B. valaisiana complex. B. valaisiana has not previously been reported in Sweden. B. afzelii DNA was found in 14 ticks (44%), and B. garinii DNA was found in 10 ticks (31%). B. burgdorferi sensu stricto DNA was found in four ticks (13%). We conclude that all of the known human-pathogenic species (B. garinii, B. afzelii, and B. burgdorferi sensu stricto) and B. valaisiana found elsewhere in Europe are also present in the Swedish host-seeking tick population and that a B. miyamotoi-like Borrelia species seems to be present in I. ricinus ticks in Europe.Ticks transmit many clinically important pathogens of the genus Borrelia. These spirochetes are responsible for two groups of human disease: Lyme borreliosis (LB) and relapsing fever (RF). LB is the most prevalent tick-borne zoonosis in Europe and North America and affects the skin, joints, heart, and nervous system (31). Borreliae that cause LB are transmitted by hard ticks of the genus Ixodes. In Europe the principal vector is Ixodes ricinus. The disease is caused by spirochetes of the Borrelia burgdorferi sensu lato complex, which consists of 10 different named genospecies. Three species, all found in Europe, are known to be pathogenic for humans: B. burgdorferi sensu strico, B. garinii (4), and B. afzelii (4, 9). Another two species, B. valaisiana (34) and B. lusitaniae (17), have been isolated from European ticks. The pathogenic capabilities of the last two species are still uncertain, although B. valaisiana DNA has been amplified by PCR from patients with LB (29). Two additional Borrelia species have been found in European patients with LB; B. bissettii sp. nov. (26) has been isolated from patients in Slovakia (25), and a novel Borrelia species has been isolated from a patient in The Netherlands (35). There has been an increasing interest in the clinical and diagnostic implications of the different Borrelia species, since an association between the clinical manifestations of LB and the infective species has been suggested (3, 9, 22, 33). The infective Borrelia species also influences the immune response (8, 30).Tick-borne RF, with periodic febrile episodes as the main symptom, is caused by a genetically and e...

Incidence and hospitalisation rates of Lyme borreliosis, France, 2004 to 2012

“…In contrast, all four pathogenic genospecies of B. burgdorferi s.l. are present in Europe, although most of the LB cases are caused by B. afzelii and B. garinii (Fraenkel et al, 2002;Oehme et al, 2002;Ornstein et al, 2002;Santino et al, 2002). B. afzelii predominates in the northern, central and eastern parts of Europe, and B. garinii in the western parts.…”

‘Candidatus Borrelia texasensis’, from the American dog tick Dermacentor variabilis

“…Moreover, 'Borrelia lonestari' has been detected and cultured in the hard tick Amblyomma americanum from the US states of Texas, New Jersey, New York, Missouri and Georgia (Barbour et al, 1996;Varela et al, 2004), and a Borrelia species genetically close to Borrelia miyamotoi has been detected in Ixodes scapularis from Rhode Island, Connecticut, New York and New Jersey (Scoles et al, 2001). Also, a B. miyamotoi-like Borrelia species appears to be present in Ixodes ricinus ticks in Europe (Fraenkel et al, 2002). In Japan, B. miyamotoi is vectored by the closely related Ixodes persulcatus, which also is a vector of the Lyme borreliosis spirochaetes Borrelia garinii and Borrelia afzelii (Fukunaga & Koreki, 1995).…”

Borrelia miyamotoiInfections among Wild Rodents Show Age and Month Independence and Correlation withIxodes persulcatusLarval Attachment in Hokkaido, Japan

“…In Japan, B. miyamotoi is carried by the vector tick Ixodes persulcatus, as it is in other parts of Asia (Fukunaga et al 1995, Fomenko 2010. I. scapularis, I. pacificus, and I. ricinus are the vectors in their respective ranges in other parts of the world (Fraenkel et al 2002, Mun et al 2006, Barbour et al 2009). …”