Showing papers by "Gereon Schares published in 2016"

Relationship between seroprevalence in the main livestock species and presence of Toxoplasma gondii in meat (GP/EFSA/BIOHAZ/2013/01)An extensive literature review. Final report

Abstract: Relationship between seroprevalence in the main livestock species and presence of Toxoplasma gondii in meat | EURLworkshop Rome 2016 3 Joke van der Giessen, Marieke Opsteegh, Gereon Schares, Radu Blaga, Miriam Maas, Franz Conrathsb, Berit Bangourac, Radu Blagad, Pascal Boireaud, Isabelle Valleed, Vitomir Djokicd, Delphine Le Rouxd, Catherine Perret-Duménild, Tamara Ducryd, Henk Wisselinke, Jan Cornelissene, Isabelle Villenaf, Dominique Aubertf, Adriana Györkeg, Vasile Cozmag, Viorica Mirceang, Anamaria Ioana Paștiug, Anamaria Baleag, Zsuzsa Kalmarg, Diana Bărburașg, Edoardo Pozioh, Furio Spanoh Georgina Limoni, Milen Georgievi, Damer Blakei, Javier Guitiani, Javier Dominguezj, Frank Katzerk, Alison Burrellsk , Lee Innesk, Olgica Djurkovic-Djakovicl, Ivana Klunl,

Sarcocystis rommeli, n. sp (Apicomplexa : Sarcocystidae) from cattle (Bos taurus) and its differentiation from Sarcocystis hominis

Abstract: R. Calero-Bernal is a postdoctoral fellow (ref. PO12010) funded by the Department of Employment and Innovation of the Regional Government of Extremadura (Spain) and the European Social Fund.

Emergence of cutaneous neosporosis in a dog receiving immunosuppressive therapy: molecular identification and management.

Abstract: BACKGROUND Neosporosis is a multisystemic disease caused by the intracellular protozoan Neospora caninum. In dogs the disease primarily affects the central nervous system. Canine cutaneous neosporosis is a rare condition often associated with old age or concurrent immunosuppressive treatments for different underlying conditions. ANIMALS A 10-year-old female spayed golden retriever dog affected by primary immune-mediated myelofibrosis and treated with immunosuppressive therapies for 6 weeks that developed severe cutaneous lesions. METHODS Definitive diagnosis was based on several investigation techniques including serology (immunoblotting), immunohistochemistry (IHC), species-specific conventional and real-time PCR, and DNA sequencing. RESULTS Remission of cutaneous neosporosis was obtained with the administration of clindamycin while the concurrent immunosuppressive therapy was maintained to manage the underlying primary condition. CONCLUSIONS AND CLINICAL IMPORTANCE To the best of the authors' knowledge this is the first report of species-specific PCR and DNA sequencing used as diagnostic methods for canine cutaneous neosporosis emerging in a dog receiving immunosuppressive therapy.

Besnoitia besnoiti lytic cycle in vitro and differences in invasion and intracellular proliferation among isolates

Abstract: Bovine besnoitiosis, caused by the protozoan Besnoitia besnoiti, reduces productivity and fertility of affected herds. Besnoitiosis continues to expand in Europe and no effective control tools are currently available. Experimental models are urgently needed. Herein, we describe for the first time the kinetics of standardised in vitro models for the B. besnoiti lytic cycle. This will aid to study the pathogenesis of the disease, in the screening for vaccine targets and drugs potentially useful for the treatment of besnoitiosis. We compared invasion and proliferation of one B. tarandi (from Finland) and seven B. besnoiti isolates (Bb-Spain1, Bb-Spain2, Bb-Israel, Bb-Evora03, Bb-Ger1, Bb-France, Bb-Italy2) in MARC-145 cell culture. Host cell invasion was studied at 4, 6, 8 and 24 h post infection (hpi), and proliferation characteristics were compared at 24, 48, 72, 96, 120, and 144 hpi. In Besnoitia spp., the key parameters that determine the sequential adhesion-invasion, proliferation and egress steps are clearly distinct from those in the related apicomplexans Toxoplasma gondii and Neospora caninum. Besnoitia spp. host cell invasion is a rather slow process, since only 50 % of parasites were found intracellular after 3–6 h of exposure to host cells, and invasion still took place after 24 h. Invasion efficacy was significantly higher for Bb-France, Bb-Evora03 and Bb-Israel. In addition, the time span for endodyogeny to take place was as long as 18–35 h. Bb-Israel and B. tarandi isolates were most prolific, as determined by the tachyzoite yield at 72 hpi. The total tachyzoite yield could not be predicted neither by invasion-related parameters (velocity and half time invasion) nor by proliferation parameters (lag phase and doubling time (dT)). The lytic cycle of Besnoitia was asynchronous as evidenced by the presence of three different plaque-forming tachyzoite categories (lysis plaques, large and small parasitophorous vacuoles). This study provides first insights into the lytic cycle of B. besnoiti isolates and a standardised in vitro model that allows screening of drug candidates for the treatment of besnoitiosis.

Negative Impact of Hypoxia on Tryptophan 2,3-Dioxygenase Function.

Abstract: Tryptophan is an essential amino acid for hosts and pathogens. The liver enzyme tryptophan 2,3-dioxygenase (TDO) provokes, by its ability to degrade tryptophan to N-formylkynurenine, the precursor of the immune-relevant kynurenines, direct and indirect antimicrobial and immunoregulatory states. Up to now these TDO-mediated broad-spectrum effector functions have never been observed under hypoxia in vitro, although physiologic oxygen concentrations in liver tissue are low, especially in case of infection. Here we analysed recombinant expressed human TDO and ex vivo murine TDO functions under different oxygen conditions and show that TDO-induced restrictions of clinically relevant pathogens (bacteria, parasites) and of T cell proliferation are abrogated under hypoxic conditions. We pinpointed the loss of TDO efficiency to the reduction of TDO activity, since cell survival and TDO protein levels were unaffected. In conclusion, the potent antimicrobial as well as immunoregulatory effects of TDO were substantially impaired under hypoxic conditions that pathophysiologically occur in vivo. This might be detrimental for the appropriate host immune response towards relevant pathogens.