The article, titled “Established and emerging pathogens in Ixodes ricinus ticks collected from birds on a conservation island in the Baltic Sea,” looked at the potential role of migrating birds in the spread of tick-borne infections such as Lyme disease and babesiosis. Here’s the abstract:
Tick-borne pathogens such as Lyme borreliosis spirochaetes, Anaplasma phagocytophilum, Rickettsia spp. and Babesia spp. cause a great variety of diseases in animals and humans. Although their importance with respect to emerging human diseases is increasing, many issues about their ecology are still unclear. In spring 2007, 191 Ixodes ricinus (Acari: Ixodidae) ticks were collected from 99 birds of 11 species on a bird conservation island in the Baltic Sea in order to test them for Borrelia spp., A. phagocytophilum, Rickettsia spp. and Babesia spp. infections. Identification of the pathogens was performed by polymerase chain reaction (PCR), restriction fragment length polymorphism and sequence analysis. The majority of birds with ticks testing positive were European robins and thrushes. Borrelia DNA was detected in 14.1%, A. phagocytophilum in 2.6%, rickettsiae in 7.3% and Babesia spp. in 4.7% of the ticks. Co-infections with different pathogens occurred in six ticks (3.1%). The fact that 11 ticks (five larvae, six nymphs) were infected with Borrelia afzelii suggests that birds may, contrary to current opinion, serve as reservoir hosts for this species. Among rickettsial infections, we identified Rickettsia monacensis and Rickettsia helvetica. As we detected five Rickettsia spp. positive larvae and two birds carried more than one infected tick, transmission of those pathogens from birds to ticks appears possible. Further characterization of Babesia infections revealed Babesia divergens and Babesia microti. The occurrence of Babesia spp. in a total of five larvae suggests that birds may be able to infect ticks, at least with Ba. microti, a species considered not to be transmitted transovarially in ticks.
But, as the retraction notice explains, the findings weren’t exactly novel:
The following article from Medical and Veterinary Entomology, ‘Established and emerging pathogens in Ixodes ricinus ticks collected from birds on a conservation island in the Baltic Sea’ by J. Franke, F. Meier, A. Moledenhauer, E. Straube, W. Dorne and A. Hildebrandt, published online on 26 September 2010 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal Editors, Doug D. Colwell, Mary Cameron, Domenico Otranto and Hilary Ranson and Blackwell Publishing Ltd. and with the knowledge of the authors. The retraction has been agreed due to overlap between this article and the following articles published in the journal Ticks and Tick-borne Diseases:
‘The potential role of migratory birds in transmission cycles of Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp.’ by Anke Hildebrandt, Jan Franke, Frank Meier, Svea Sachse, Wolfram Dorn and Eberhard Straube. Ticks and Tick-Bourne Diseases, Volume 1 Issue 2, 2010, pages 105–107 DOI: 10.1016/j.ttbdis.2009.12.003
Are birds reservoir hosts for Borrelia afzelii? By Jan Franke, Anja Moldenhauer, A., Anke Hildebrandt, Wolfram Dorn, Ticks and Tick-Borne Diseases, Volume 1 Issue 2, 109–112 DOI: 10.1016/j.ttbdis.2010.03.001
The now-retracted paper has been cited twice, according to Thomson Scientific’s Web of Knowledge.
Douglas Colwell, editor of MVE, told us:
The article in MVE that was retracted contained the same data as the two articles published in Ticks and Tick-borne Diseases. Checking the timelines revealed that submission to MVE was after the submissions to TTBDis. The retraction wording was specified by the publisher.
How similar were the papers? Well, here’s the abstract from the second one in TTBD:
It is known that birds are competent reservoir hosts of particular Borrelia species like B. garinii and B. valaisiana but not for B. afzelii, a rodent-associated genospecies. Since they can carry infected ticks over long distances, they are also important covectors for Lyme borreliosis spirochaetes. To assess the role of different bird species in transmission and dispersal of Borrelia OspA types, we examined 191 Ixodes ricinus ticks from 99 birds, captured on a German conservation island in the Baltic Sea in spring 2007. Surprisingly, more than one third of the 27 positive samples were identified as B. afzelii. The cause for this unusually high prevalence remains unknown, indicating the need of further studies on bird-feeding ticks that should include a higher sample size.
Looks pretty close — as does the abstract from the first article:
Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp. are potentially emerging tick-borne pathogens, whereas many issues about their ecology, e.g. reservoir host specificity, are still unclear. In spring 2007, we collected 191 feeding Ixodes ricinus ticks from 99 birds of 11 different species on a German bird conservation island in the Baltic Sea. Babesia spp. were detected in 4.7% (9/191), A. phagocytophilum was present in 2.6% (5/191), and Rickettsia spp. were identified in 7.3% (14/191) of the investigated ticks. Further characterization of Babesia spp. infections resulted in B. divergens and B. microti. Among the Rickettsia spp. infections, we identified at least 2 different species: R. monacensis and R. helvetica. Furthermore, 2 ticks harboured mixed infections. Our study provides first interesting insights into the role of migratory birds in the distribution of several emerging tick-borne pathogens.
Close, but not identical. As Colwell notes:
To be absolutely fair, the article published in Medical and Veterinary Entomology contained the same data as in the two articles in TTBDis with the addition of data on 6 birds that had dual infections. It was our determination that this constituted ‘substantial overlap’
Still, we do wonder: Given how similar the two TTBD papers are, will the journal be retracting one of them? We’ve asked the editor and will update this post if we learn more.
Updated 1/11/2012, 11:05 am: Jochen Süss, editor of TTBD, responded to our query and had this to say:
As stated in the Abstracts, one paper reports the occurrence of Borrelia s.l., whereas the other deals with Babesia, Anaplasma and Rickettsia. The only overlap is that the same pool of 191 Ixodes ricinus ticks from the same pool of 99 birds was used for both investigations. Upon your message, I have carefully re-checked not only the Abstracts but also the complete articles. Also in the whole text there is no overlapping data. Thus, my conclusion is that it was legitimate for the authors to publish these two data sets (Borrelia s.l. on the one hand and Babesia, Anaplasma and Rickettsia on the other) as two separate articles in TTBDIS.