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Biology and Distribution of Ticks of Medical Importance
Published in Jürg Meier, Julian White, Handbook of: Clinical Toxicology of Animal Venoms and Poisons, 2017
André Aeschlimann, Thierry A. Freyvogel
A surprisingly wide variety of pathogens are transmitted by ticks. They include microorganisms, protozoans and metazoans9. Ticks might be the most versatile vectors among the arthropods; they are capable of transmitting the highest number of different pathogen species. This applies to tick species as well as to single specimens. Ixodes ricinus, e.g., may harbour simultaneously TBE virus, Borrelia burgdorferi and Rickettsia helvetica. Among the microorganisms there are obligatory intracellular organisms (e.g. tick-borne encephalitis viruses and rickettsiae of the spotted fever group), and other bacteria, including various spiro-chaetes like Borrelia burgdorferi, the agent of Lyme disease, or B.duttoni, the agent of African relapsing fever. It is even suspected that Yersinia tularensis may be transmitted by ticks. The tick borne protozoans include several species of Babesia and of Theileria. Among the metazoans transmitted by ticks one finds filarial helminths such as Acanthocheilonema (Dipetalonema) and Macdonaldius.
Prevalence of Spotted Fever Group Rickettsia in North-Eastern Poland
Published in Infectious Diseases, 2019
Karol Borawski, Justyna Dunaj, Piotr Czupryna, Sławomir Pancewicz, Renata Świerzbińska, Agnieszka Żebrowska, Anna Moniuszko-Malinowska
Rickettsia taxonomy includes four groups: Typhus group, Spotted Fever Group, Rickettsia bellii and Rickettsia canadensis groups. Rickettsia is small (0.3–0.5; 0.8–2.0 μm Gram-negative obligate intracellular bacilli. Spotted Fever Group rickettsiosis belongs to tick-borne diseases. In Poland three species are considered to be the etiological agents of Spotted Fever Group infections: Rickettsia slovaca, Rickettsia raoultii and Rickettsia helvetica. They are transmitted by Ixodes and Dermacentor ticks [5]. Ticks can be infected with Rickettsia spp. transovarially and transstadially [8,9]. The Spotted Fever Group Rickettsia commonly present with non-specific clinical signs and symptoms. Average incubation period is 3–12 d after a tick bite. Symptoms include fever, headache, muscle and articular pain, maculopapular or papulovesicular rash, in some cases – black eschar or ulcerative skin lesion in the bitten area. Lymph nodes enlargement is observed [10].
More than just Borrelia? A study of co-infection and etiology in erythema migrans patients from southernmost Sweden
Published in Infectious Diseases, 2019
Lukas Frans Ocias, Ram Benny Dessau, Charlotte Sværke Jørgensen, Karen Angeliki Krogfelt, Katharina Ornstein
The study patients were clinically diagnosed with EM by experienced physicians, thus reflecting the day-to-day practice at Swedish clinics. Further, as 43% of the cultured biopsies were verified by PCR, we can be sure that ticks were attached to these patients for a time of sufficient duration to transmit Bbsl. However, the samples tested were obtained in the years 1994–1997 and it is possible that the presence and distribution of tick-borne organisms in southernmost Sweden has changed over the years. This has to be kept in mind when extrapolating the results to a more contemporary setting. Moreover, long-term storage of the samples could have reduced the sensitivity of the molecular analysis. However, as all samples were stored in −80 °C, we do not expect this to have been a major problem. It is also important to keep in mind that some patients exposed to SFG rickettsiae or A. phagocytophilum could have seroconverted or displayed an increase in IgG titer prior to the initial visit thus eluding detection in our study. Finally, Rickettsia rickettsii was used as antigen which could have reduced the sensitivity of our serological assay to other species of SFG rickettsiae. Nevertheless, due to the general homology among the SFG rickettsiae we expect our assay to be capable of detecting most SFG rickettsiae, including Rickettsia helvetica, the most common SFG rickettsiae in field-collected ticks from Sweden.