By Linda on Jan 19, 2011 in Infections | comments(0)
Excerpt:
Among the 20 tick species described in Switzerland, Ixodes ricinus, the most
frequent one, is implicated in the transmission of pathogenic agents. Lyme
borreliosis and tick-borne encephalitis (TBE) are the major tick-borne
diseases transmitted to human.
**Presently 5 Borrelia species, belonging to the group Borrelia burgdorferi,
are recognized as human pathogens**.
The risks of infection depend on the stage of the vector, the multiple
hosts, the pathogenic agent, as well as human behavior in nature.
The detection of other pathogenic agents in ticks: Anaplasma, Babesia and
Rickettsia predispose to infections or co-infections. Results of
sero-epidemiologic studies suggest human infections. Active surveillance by
physicians is necessary and clinical studies are required to evaluate the
importance of these infections in Switzerland.
By Linda on May 31, 2010 in Infections | comments(0)
Excerpt:
Borrelia burgdorferi sensu lato, carried by Ixodes ticks, is one of the most significant human pathogens, causing Lyme disease. As there is no standardized PCR method for detection and identification of spirochaete DNA, we carried out a comparative analysis using a set of complementary primers for three regions in the genomic DNA of these bacteria (genes fla and rrs and the non-coding rrs–rrlA region). DNA extracted from 579 Ixodes ricinus ticks was subjected to nested PCR. DNA of the examined spirochaetes was detected in 43 (7.4 %) lysates when the fla gene was used as a molecular marker, in 7 (1.2 %) lysates when using primers complementary to the rrs gene, and in 12 (2.1 %) lysates using primers complementary to the non-coding rrs–rrlA sequence. RFLP analysis based on the fla gene helped identify species from the B. burgdorferi sensu lato complex (B. burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii, Borrelia valaisiana), detect co-infections, and also identify Borrelia miyamotoi. Therefore, the fla gene is the most sensitive and specific molecular marker for the detection and identification of Borrelia spirochaetes in I. ricinus.
