Modeling the Life Cycle of the Intramitochondrial Bacterium “ Candidatus Midichloria mitochondrii” Using Electron Microscopy Data

Our results suggest that Midichloria mitochondrii , the intramitochondrial bacterium, does not invade mitochondria like predatory bacteria do but instead moves from mitochondrion to mitochondrion within the oocytes of Ixodes ricinus . A better understanding of the lifestyle of M. mitochondrii will allow us to better define the role of this bacterial symbiont in the host physiology.

Molecular Evidence of Hemolivia mauritanica, Ehrlichia spp. and the Endosymbiont Candidatus Midichloria Mitochondrii in Hyalomma aegyptium Infesting Testudo graeca Tortoises from Doha, Qatar

Tick-borne agents constitute a growing concern for human and animal health worldwide. Hyalomma aegyptium is a hard tick with a three-host life cycle, whose main hosts for adults are Palearctic tortoises of genus Testudo. Nevertheless, immature ticks can feed on a variety of hosts, representing an important eco-epidemiological issue regarding H. aegyptium pathogens circulation. Hyalomma aegyptium ticks are vectors and/or reservoirs of various pathogenic agents, such as Ehrlichia, Anaplasma, Babesia and Hepatozoon/Hemolivia. Ehrlichia and Anaplasma are emergent tick-borne bacteria with a worldwide distribution and zoonotic potential, responsible for diseases that cause clinical manifestations that grade from acute febrile illness to a fulminant disease characterized by multi-organ system failure, depending on the species. Babesia and Hepatozoon/Hemolivia are tick-borne parasites with increasing importance in multiple species. Testudo graeca tortoises acquired in a large animal market in Doha, Qatar, were screened for a panel of tick-borne pathogens by conventional PCR followed by bidirectional sequencing. The most prevalent agent identified in ticks was Hemolivia mauritanica (28.6%), followed by Candidatus Midichloria mitochondrii (9.5%) and Ehrlichia spp. (4.7%). All samples were negative for Babesia spp. and Hepatozoon spp. Overall, 43% of the examined adult ticks were infected with at least one agent. Only 4.7% of the ticks appeared to be simultaneously infected with two agents, i.e., Ehrlichia spp. and H. mauritanica. This is the first detection of H. mauritanica, Ehrlichia spp. and Candidatus M. mitochondrii in H. aegyptium ticks collected from pet spur-thighed tortoises, in Qatar, a fact which adds to the geographical extension of these agents. The international trade of Testudo tortoises carrying ticks infected with pathogens of veterinary and medical importance deserves strict control, in order to reduce potential exotic diseases.