The results indicate that increased awareness of the importance of pre-travel vaccination is needed among the travellers in order to improve their KAP.

Since the year 2000, clinical patterns resembling tick-borne rickettsioses have been noticed in China-Russia border areas. Epidemiological data regarding species of the aetiological agent, tick vector prevalence and distribution as well as incidence of human cases in the areas are still sparse to date. In order to identify Rickettsia species occurring in the areas, we investigated Dermacentor silvarum collected in the selected areas. Rickettsia raoultii was the predominant Rickettsia found in D. silvarum evident with ompA, ompB, gltA and 17 kDa protein genes. The Rickettsia prevalence in D. silvarum appeared to be 32.25 % with no sex difference. The results extend the common knowledge about the geographic distribution of R. raoultii and its candidate vector tick species, which suggest an emerged potential threat of human health in the areas.

BackgroundCases of Mediterranean Spotted Fever like rickettsioses, caused by Rickettsia monacensis, have become more common in the last 10 years. In China, natural infection of R. monacensis in various tick species has been confirmed but the vector(s) of R. monacensis have not been recorded.MethodsThe prevalence of R. monacensis in >1500 Ixodidae ticks from central and southern China was determined using centrifugation-shell vial culture and polymerase chain reaction techniques. The predominant species, Ixodes sinensis, harbored a natural infection of R. monacensis and was assumed to be a vector candidate of R. monacensis. Experimental transmissions were initialized by infecting Rickettsia-free tick colonies with R. monacensis using capillary tube feeding (CTF) or immersion techniques. Transstadial and transovarial transmissions, and transmission from ticks to mice, were conducted under laboratory conditions.ResultsR. monacensis was isolated and identified from hemolymph of Ixodes sinensis using molecular techniques. Transovarial transmission of R. monacensis from infected ♀I. sinensis to offspring was documented and infected offspring successfully passed Rickettsia to mice. Transstadial transmission rates were 58% in larva to nymph and 56% in nymph to adult stages. Infected nymphs and adults were also able to infect mice.ConclusionsI. sinensis is a competence vector for R. monacensis as demonstrated by natural infection and transmission studies.

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To investigate the likely source population and candidate vectors of Candidatus Rickettsia tarasevichiae, the prevalence of this bacteria was quantified in specimens of four tick species that mainly parasitize humans collected from 13 sites along the Chinese-Russian border. The presence of the bacteria was determined by detecting its specific citrate synthase (gltA) partial gene and outer membrane protein A (ompA) partial gene. Only Ixodes persulcatus Schulze was found to be naturally infected with C. R. tarasevichiae, which had an overall prevalence of 1.53% in both sexes. C. R. tarasevichiae is an emerging, tick-borne human pathogen and this finding may partially explain recent human cases of infection by this organism in China. Public health authorities should be aware of the potential risk posed by the transmission of this bacterium to humans by ticks.