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Scheid P.,Central Institute of the Bundeswehr Medical Service | Scheid P.,University of Koblenz-Landau
Current Opinion in Microbiology

A lot of endocytobionts (or endosymbionts) have been discovered within free-living amoebae in recent years. In this article the results of a long lasting effort to derive valuable data about an extraordinary spore-like infectious microorganism (endocytobiont, endosymbiont) within host amoebae (Acanthamoeba sp.) recently isolated from the contact lens case of a patient with keratitis, are presented. It took some time until this endocytobiont could be attributed to the genus Pandoravirus following a publication of two other pandoraviruses isolated from aquatic environments. Consequently the molecular biological investigation led to the taxonomic affiliation of the endocytobiont with the genus Pandoravirus and to the description of a new Pandoravirus species, Pandoravirus inopinatum after whole-genome sequencing in 2015. The fact that it was isolated from a contact lens container of a keratitis patient gives another dimension to these findings showing paradigmatically, how readily these 'new' giant viruses get to humans. © 2016 Elsevier Ltd. Source

The Horn of Africa represents a region formerly known to be highly susceptible to mosquito-borne infectious diseases. In order to investigate whether autochthonous WNV transmission occurs in the Djibouti City area, in how far, and which of, the endemic Culex mosquito species are involved in WNV circulation activity,and whether sentinel site-enhanced near-real time surveillance (SSE-NRTS) may increase WNV detection sensitivity, mosquito vector monitoring was conducted from January 2010 to June 2012. Six monitoring locations, including two identified sentinel sites, considered most probable for potential anthroponotic and zoonotic virus circulation activity, have been continuously employed. Among the 20431 mosquitoes collected, 19069 (93.4%) were Cx. quinquefasciatus, and 1345 (6.6%) Cx. pipiens ssp. torridus. WNV lineage 2 circulation activity was detected between December 20th, 2010 and January 7th, 2011. Overall, 19 WNV RNA-positive mosquito pools were detected. Generally, urban environment-specific WNV-RNA circulation took place in Cx. pipiens ssp. torridus, whereas periurban and rural area-linked circulation was detected only in Cx. quinquefasciatus. Serological investigation data from 10 volunteers employed at the dislocated zoonotic WNV transmission sentinel site suggest that six persons (60%) had an acute, or recent, WNV infection. Results show that WNV should be considered endemic for Djibouti and sentinel site-enhanced near-real time surveillance is an elegant and highly effective epidemiological tool. In Djibouti, the endemicity level, public health impact and transmission modes of vector-borne diseases in concordance with locally optimized monitoring and control regimen deserve further investigation. Source

Scheid P.,Central Institute Of The Bundeswehr Medical Service Koblenz Andernacherstr 100 | Hauroder B.,Central Institute of the Bundeswehr Medical Service | Michel R.,Central Institute Of The Bundeswehr Medical Service Koblenz Andernacherstr 100
Parasitology Research

In this article, the results of investigations concerning a parasitic endocytobiont within the host amoebae (Acanthamoeba sp.) are presented. The endocytobiont was recently isolated from the contact lens and the inflamed eye of a patient with keratitis. Light microscopy and electron microscopy were performed to provide morphological details: Light microscopy revealed the presence of ovoid microorganisms developing and proliferating within the cytoplasm of the amoebic trophozoites. Details of the unusual development of these endocytobionts within the amoebae could be studied and demonstrated by means of electron microscopy. Foldings and morphological reorganization of the microorganisms took place exclusively within the host cytoplasm. The intracellularly aggregating organisms led to the rupture of the Acanthamoeba trophozoites after proliferation. Numerous microorganisms were released, which were infectious and were subsequently ingested by hitherto uninfected acanthamoebic trophozoites. To evaluate the in vitro growth of the isolated endocytobionts (without their hosts), they were transferred to several different culture plates. There was no growth of these unique organisms on five different common cultural plates suitable for the growth of bacteria and fungi. © 2010 Springer-Verlag. Source

Sharma V.,Aix - Marseille University | Colson P.,Aix - Marseille University | Colson P.,Institut Universitaire de France | Chabrol O.,Aix - Marseille University | And 4 more authors.
Frontiers in Microbiology

Nucleocytoplasmic large DNA viruses, or representatives of the proposed order Megavirales, belong to families of giant viruses that infect a broad range of eukaryotic hosts. Megaviruses have been previously described to comprise a fourth monophylogenetic TRUC (things resisting uncompleted classification) together with cellular domains in the universal tree of life. Recently described pandoraviruses have large (1.9-2.5 MB) and highly divergent genomes. In the present study, we updated the classification of pandoraviruses and other reported giant viruses. Phylogenetic trees were constructed based on six informational genes. Hierarchical clustering was performed based on a set of informational genes from Megavirales members and cellular organisms. Homologous sequences were selected from cellular organisms using TimeTree software, comprising comprehensive, and representative sets of members from Bacteria, Archaea, and Eukarya. Phylogenetic analyses based on three conserved core genes clustered pandoraviruses with phycodnaviruses, exhibiting their close relatedness. Additionally, hierarchical clustering analyses based on informational genes grouped pandoraviruses with Megavirales members as a super group distinct from cellular organisms. Thus, the analyses based on core conserved genes revealed that pandoraviruses are new genuine members of the 'Fourth TRUC' club, encompassing distinct life forms compared with cellular organisms. © 2015 Sharma, Colson, Chabrol, Scheid, Pontarotti and Raoult. Source

Scheid P.,Central Institute of the Bundeswehr Medical Service | Balczun C.,Ruhr University Bochum | Schaub G.A.,Ruhr University Bochum
Parasitology Research

In this article, the results of a long effort to derive valuable phylogenetic data about an extraordinary spore-like infectious particle (endocytobiont) within host amoebae (Acanthamoeba sp.) recently isolated from the contact lens and the inflamed eye of a patient with keratitis are presented. The development of these endocytobionts has already been demonstrated with electron microscopic photo sequences, leading to a relevant model of its development presented here. The molecular biological investigation following the discovery of two other Pandoravirus species within aquatic sediments in 2013 led to the taxonomic affiliation of our endocytobiont with the genus Pandoravirus. A range of endocytobionts (intracellular biofilms) have been found in recent years, among which are several viruses which obligatorily proliferate within free-living amoebae. In human medicine, foreign objects which are placed in or on humans cause problems with microorganisms in biofilms. Contact lenses are especially important, because they are known as a source of a rapid formation of biofilm. These were the first Pandoraviruses described, and because this is additionally the first documented association with humans, we have clearly demonstrated how easily such (viral) endocytobionts can be transferred to humans. This case counts as an example of parasites acting as vectors of phylogenetically different microorganisms especially when living sympatric within their biocoenosis of biofilms. As the third part of the “Pandoravirus trilogy”, it finally reveals the phylogenetic nature of these “extraordinary endocytobionts” within Acanthamoebae. © 2014, Springer-Verlag Berlin Heidelberg. Source

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