leona gilbertLeona GilbertLyme Disease is the most commonly reported tick-borne infection in Europe and North America, and is endemic in 63 countries all over the world including the 27 EU countries. The disease, first described in Old Lyme, Connecticut in 1975, is caused by a spiral-shaped spirochete Borrelia burgdorferi as a consequence of a bite from infected Ixodes genus ticks. This pathogen has also been found in the midgut of mosquites, Culex pipiens and Aedes vexans and other blood sucking flies, which leads to the idea that transmission may be possible by other arthropods. There are 17 genospecies in B. burgdorferi sensu lato group, which have differences in vector species and pathogenicity. The most established Borrelia burgdorferi genospecies in Europe are B. garinii, B. afzelii and to a lesser extent B. burgdorferi sensu stricto that is predominant in USA.

The different Borrelia species have been carried into new habitats by a variety of ticks, such as the deer and bear ticks, and their vectors - birds, deer, rodents and other animal species. With a high prevalence of Borrelia infection (18 %) in ticks in Europe, it is important to realize that disease prevalence is underestimated as few countries have made Lyme disease a compulsorily notifiable disease. This is also supported by the fact that WHO indicated that the disease incidence is grossly miscalculated and many infections go undiagnosed. Additionally, CDC has recently reported that the occurrence of Lyme disease has been 10 fold underestimated and predict an annual of 300,000 new cases every year. Borrelia burgdorferi is pleomorphic in morphology, nonetheless there is a long-standing debate regarding if pleomorphism of bacteria in general exists and if pleomorphic forms are actually pathogenic in nature. Here we have a developing hypothesis that the pleomorphic forms of Borrelia allows the bacteria to be sleath and evade the immune system, thereby establishing chronic infections and autoimmune-like disease states. Recent research finding suggest that pleomorphic forms are easily induced and that these forms are bioactive. Additionally, these pleomorphic forms of Borrelia are recognized by the innate immune system and can induce immune responses. Taken together, the results indicated that B. burgdorferi can change morphology very quickly, adapt and survive in hostile environments, and have pleomorphic forms consisting of DNA as well as antigenic relevant proteins that are freely recognized by the immune system. These results imply that Borrelia and its pleomorphic forms have access to immune cells. The recognition and detection of pleomorphic forms is detrimental for proper diagnosis, treatment and prevention of chronic Borrelia infections. In conclusion, the simple knowledge that B. burgdorferi has definite pleomorphic morphologies at that can be easily obtained by changes in environmental conditions may enhance future immunologically studies, help in improving the life quality of infected patients, and provide a model system to investigate other B. burgdorferi subspecies and other spirochetal pathogens.

Dette foredraget er en del av BIO-konferansen 2013.
Foredraget er på engelsk.

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