In Africa, the most prevalent tick-­‐borne pathogens are considered to be those belonging to the genera Rickettsia, Anaplasma, Ehrlichia, Babesia, and Theileria. Very few data on ticks and tick-­‐borne diseases in Africa are found in the literature, notwithstanding their great economic, veterinary and medical impact. Considering that tick symbiotic bacteria can also play important roles in host biology and vector efficiency, we investigated the co-­‐presence of pathogenic and symbiotic bacteria in hard ticks collected from wild and domestic animals from different ecological areas in Kenya, Egypt, and Ethiopia. Taxonomic identification of ticks was performed by means of both morphological (light microscopy) and molecular (12S rRNA PCR) techniques. Tick DNAs were then screened for the presence of pathogenic and symbiotic microorganisms through ad-­‐hoc molecular approaches (PCR). Overall, 358 hard ticks were taxonomically identified as belonging to Ixodes, Amblyomma, Hyalomma, Rhipicephalus, Dermacentor, and Haemaphysalis genera. Pathogen screening provided information on pathogens circulation in Africa, confirming the presence of Rickettsia spp., Anaplasma spp., Ehrlichia spp., Borrelia garinii, Babesia spp. Theileria spp and Coxiella burnetii. More novel is the detection of Candidatus Cryptoplasma, a recently described α-­‐Proteobacterium belonging to the family Anaplasmataceae, for which little is known regarding pathogenic role, ecology and epidemiology. Furthermore, our work provides insights on the African scenario of tick-­‐symbiont associations showing that Coxiella endosymbionts are the most prevalent microorganisms, being detected in sixteen different tick species. An additional endosymbiont, Midichloria, was also found in 9 different tick species. Gene sequences were obtained for all PCR-­‐detected microorganisms, and subsequent phylogenetic analyses are ongoing. Statistical analyses will also be performed, to evaluate patterns of distribution of microorganisms on different hosts and ecological areas, as well as potential co-­‐occurrence and competition between pathogens and symbionts.

Molecular investigation of pathogenic and symbiotic bacteria in African hard ticks infesting wild and domestic animals

Alali S;
2019

Abstract

In Africa, the most prevalent tick-­‐borne pathogens are considered to be those belonging to the genera Rickettsia, Anaplasma, Ehrlichia, Babesia, and Theileria. Very few data on ticks and tick-­‐borne diseases in Africa are found in the literature, notwithstanding their great economic, veterinary and medical impact. Considering that tick symbiotic bacteria can also play important roles in host biology and vector efficiency, we investigated the co-­‐presence of pathogenic and symbiotic bacteria in hard ticks collected from wild and domestic animals from different ecological areas in Kenya, Egypt, and Ethiopia. Taxonomic identification of ticks was performed by means of both morphological (light microscopy) and molecular (12S rRNA PCR) techniques. Tick DNAs were then screened for the presence of pathogenic and symbiotic microorganisms through ad-­‐hoc molecular approaches (PCR). Overall, 358 hard ticks were taxonomically identified as belonging to Ixodes, Amblyomma, Hyalomma, Rhipicephalus, Dermacentor, and Haemaphysalis genera. Pathogen screening provided information on pathogens circulation in Africa, confirming the presence of Rickettsia spp., Anaplasma spp., Ehrlichia spp., Borrelia garinii, Babesia spp. Theileria spp and Coxiella burnetii. More novel is the detection of Candidatus Cryptoplasma, a recently described α-­‐Proteobacterium belonging to the family Anaplasmataceae, for which little is known regarding pathogenic role, ecology and epidemiology. Furthermore, our work provides insights on the African scenario of tick-­‐symbiont associations showing that Coxiella endosymbionts are the most prevalent microorganisms, being detected in sixteen different tick species. An additional endosymbiont, Midichloria, was also found in 9 different tick species. Gene sequences were obtained for all PCR-­‐detected microorganisms, and subsequent phylogenetic analyses are ongoing. Statistical analyses will also be performed, to evaluate patterns of distribution of microorganisms on different hosts and ecological areas, as well as potential co-­‐occurrence and competition between pathogens and symbionts.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11379/555521
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