Cette thèse est une investigation de l'écologie et de l'épidémiologie spatiale fine de la tique à pattes noires (Ixodes scapularis) et du risque associé aux pathogènes transmis par cette tique dans une forêt du sud du Québec, au Canada. Sous l’influence de changements climatiques et environnementaux, la répartition spatiale de cette tique s’étend actuellement à travers la province, et son abondance augmente dans la plupart des régions. Il en résulte une préoccupation croissante en matière de santé publique liée à l'émergence de maladies transmises par les tiques (MTT) dans la province. Ainsi, plusieurs besoins de recherche ont vu le jour, y compris l’amélioration de la compréhension des facteurs dictant où et quand le risque émergera, et l’identification des composantes sur lesquelles les autorités régionales, locales et les individus pourraient agir afin réduire ce risque. Le site d’étude pour ce projet était le parc National du Mont-Saint-Bruno. De 2016 à 2018, à 32 sites répartis dans les habitats forestiers du parc, les tiques ont été collectées par la technique de la flanelle, la communauté d’hôtes de la tique a été inventoriée (grands et petits mammifères, et oiseaux nicheurs) et les micro-habitats ont été caractérisés (en termes de structure, de composition et de conditions microclimatiques). La densité des tiques dans la zone d’étude était particulièrement élevée par rapport aux autres régions environnantes. Les analyses spatiales ont montré des patrons d’abondance des tiques, persistants sur trois ans, avec un effet significatif des conditions locales de températures et d’humidité relatives. Un effet significatif de la densité du stade de développement précédent lors de l’année précédente a également été noté, suggérant une dispersion lente des tiques par les hôtes et une dynamique d’invasion caractérisée par plusieurs évènements d’introduction et d’expansion opérant à une échelle locale. En 2017 et 2018, un dispositif d’échantillonnage plus extensif a visé la communauté d’hôtes des stades immatures d’I. scapularis, afin de documenter le rôle de ces espèces dans la circulation des agents pathogènes. 849 oiseaux nicheurs appartenant à 50 espèces et 694 petits mammifères appartenant à 4 espèces ont été examinés pour la présence des tiques et des pathogènes. Les souris à pattes blanches (Peromyscus leucopus) contribuaient à la majorité (80%) des cas d’infection des nymphes par Borrelia burgdorferi dans l’échantillon, alors que les 20% restants étaient attribuables à des oiseaux. Ce résultat confirme la proposition de certains auteurs à savoir que l’importance des hôtes alternatifs (autres que P. leucopus) aient été sous-estimée dans les études précédentes, et souligne l’importance de poursuivre les travaux pour documenter l’impact de ces hôtes dans l’épidémiologie des MTT. Finalement, la caractérisation des patrons de risque associés aux MTT dans la zone d’étude a été complétée par un échantillonnage de l’intensité d’utilisation des sentiers par les visiteurs du parc en 2017 et 2018. D’abord, les prélèvements de tiques dans l’environnement et sur les hôtes ont permis de détecter la présence de trois pathogènes représentant un risque de santé publique pour la population locale, soit en ordre du plus au moins prévalent : B. burgdorferi, Anaplasma phagocytophyllum et Borrelia miyamotoi. Ensuite, l’intégration des patrons spatiaux de l’utilisation du parc par les visiteurs a mis en évidence le rôle des facteurs comportementaux des utilisateurs et des attributs du paysage local dans la détermination des patrons de risque de contacts entre les visiteurs et les nymphes infectées par B. burgdorferi. Le risque de contact était associé à certaines périodes et zones de forte fréquentation du parc, mais pas aux indicateurs locaux de fragmentation de l'habitat, comme le suggèrent d'autres études. En outre, les zones où la densité de la couverture forestière et des points d'intérêt (infrastructures) étaient les plus élevés présentaient les niveaux de risque les plus élevés. Cette thèse contribue à l’avancement des connaissances fondamentales reliées à la biologie des tiques, aux relations écologiques entre ces ectoparasites et leurs hôtes et à l’écologie des pathogènes qu’elles transmettent. Ces connaissances trouveront de multiples applications concrètes, principalement dans le domaine de la santé publique où elles permettront notamment de parfaire les outils existants d’évaluation du risque et de prévention des MTT. En reliant l’écologie à la santé publique, cette thèse répond à un besoin de recherche et de développement d’expertise qui devient de plus en plus important dans le contexte actuel des changements climatiques et de l’émergence des maladies zoonotiques qui s’en trouvent facilitées au Canada. / This thesis is an investigation of the ecology and fine-scale spatial epidemiology of the blacklegged tick (Ixodes scapularis) and the risk associated with pathogens transmitted by this tick in a forest of southern Quebec, Canada. Under the influence of climate and environmental changes, the spatial distribution of this tick is currently expanding across the province, and its abundance is increasing in most regions. This has resulted in a growing public health threat associated with the emergence of tick-borne diseases (TBDs) in the province. Thus, several research needs have emerged, including improving understanding of the factors determining where and when risk will arise, and identifying what regional and local health authorities and individuals can do to reduce that risk. The study site for this project was Mont-Saint-Bruno National Park. From 2016 to 2018, at 32 sites distributed in the park's forest habitats, ticks were collected by drag sampling, the host community was inventoried (large and small mammals, and nesting birds), and microhabitats were characterized (in terms of structure, composition, and microclimatic conditions). The density of ticks in the study area was particularly high compared to other surrounding areas. Spatial analyses showed patterns of tick abundance, persistent over three years, with a significant effect of local microclimatic conditions (relative temperature and humidity). A significant effect of the density of the previous developmental stage in the previous year was also noted, suggesting slow host dispersal of ticks and invasion dynamics characterized by several introduction and expansion events operating at a local scale. In 2017 and 2018, a more extensive sampling scheme targeted the host community of immature stages of I. scapularis, to document the role of these species in pathogen circulation. 849 breeding birds belonging to 50 species and 694 small mammals belonging to 4 species were examined for the presence of ticks and pathogens. White-footed mice (Peromyscus leucopus) contributed to the majority (80%) of Borrelia burgdorferi nymph infections in the sample, while the remaining 20% were attributable to birds. This result confirms the suggestion by some authors that the importance of alternative hosts (other than P. leucopus) may have been underestimated in previous studies and underscores the importance of further work to document the impact of these hosts in the epidemiology of TBDs. Finally, characterization of risk patterns associated with TBDs in the study area was completed by sampling trail use by park visitors in 2017 and 2018. First, the analysis of ticks collected from the environment and on hosts demonstrated the presence of three pathogens representing a public health risk to the local population, in order from the most to the least prevalent: B. burgdorferi, Anaplasma phagocytophyllum and Borrelia miyamotoi. Second, integration of spatial patterns of visitor use of the park highlighted the role of visitor behaviour and local landscape attributes in determining patterns of risk of contact between visitors and B. burgdorferi-infected nymphs. Risk was associated with certain times and areas of increased park use, but not with local indicators of habitat fragmentation, in contrast with the results of previous studies. In addition, areas with the highest densities of forest cover and points of interest (infrastructure) had the highest levels of risk. This thesis contributes to the advancement of fundamental knowledge related to the biology of ticks, the ecological relationships between these ectoparasites and their hosts, and the ecology of the pathogens they transmit. This knowledge will have multiple applications, mainly in the field of public health, where it will allow the refinement of existing tools for risk assessment and prevention of TBDs. By linking ecology to public health, this thesis responds to a need for research and development of expertise that is becoming increasingly important in the current context of climate change and the emergence of zoonotic diseases that it facilitates in Canada.

The term aggregation refers to overdispersion and both are used interchangeably in this thesis. In addressing the problem of prevalence of infectious parasite species faced by most rural livestock farmers, we model the distribution of faecal egg counts of 15 parasite species (13 internal parasites and 2 ticks) common in sheep and goats. Aggregation and excess zeroes is addressed through the use of generalised linear models. The abundance of each species was modelled using six different distributions: the Poisson, negative binomial (NB), zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB), zero-altered Poisson (ZAP) and zero-altered negative binomial (ZANB) and their fit was later compared. Excess zero models (ZIP, ZINB, ZAP and ZANB) were found to be a better fit compared to standard count models (Poisson and negative binomial) in all 15 cases. We further investigated how distributional assumption a↵ects aggregation and zero inflation. Aggregation and zero inflation (measured by the dispersion parameter k and the zero inflation probability) were found to vary greatly with distributional assumption; this in turn changed the fixed-effects structure. Serial autocorrelation between adjacent observations was later taken into account by fitting observation driven time series models to the data. Simultaneously taking into account autocorrelation, overdispersion and zero inflation proved to be successful as zero inflated autoregressive models performed better than zero inflated models in most cases. Apart from contribution to the knowledge of science, predictability of parasite burden will help farmers with effective disease management interventions. Researchers confronted with the task of analysing count data with excess zeroes can use the findings of this illustrative study as a guideline irrespective of their research discipline. Statistical methods from model selection, quantifying of zero inflation through to accounting for serial autocorrelation are described and illustrated. / Statistics / M.Sc. (Statistics)

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Os begomovÃrus, vÃrus da famÃlia Geminiviridae transmitidos por mosca branca, tÃm emergido como sÃrios patÃgenos de culturas agronÃmicas e hortÃcolas em regiÃes tropicais e subtropicais de muitos paÃses em todo o mundo. A partir da dÃcada de 80, tÃm aumentado os relatos da disseminaÃÃo da mosca branca, Bemisia argentifolii, e de begomovÃrus provocando impacto devastador nas regiÃes em que ocorrem. No Brasil, estes patÃgenos tÃm sido limitantes para a produÃÃo de tomate (Lycopersicon esculentum) em vÃrias Ãreas de cultivo com incidÃncia crescente desde 1994. No presente trabalho, plantas de tomate exibindo sintomas de infecÃÃo provocada por vÃrus como mosaico, clorose internerval, enrolamento do limbo foliar e reduÃÃo do crescimento, foram coletadas em lavouras de tomate indÃstria em AnÃpolis-GO. O vÃrus foi identificado como pertencente ao gÃnero Begomovirus mediante tÃcnica de PCR usando oligonucleotÃdeos especÃficos que amplificaram fragmentos dos componentes A e B do genoma viral. No capÃtulo I sÃo apresentados os resultados da caracterizaÃÃo molecular e no capÃtulo II, os dados da determinaÃÃo do cÃrculo de hospedeiros e da investigaÃÃo da relaÃÃo do begomovÃrus com o vetor Bemisia argentifolii. O isolado denominado GOANPL, foi clonado e parcialmente seqÃenciado tendo sido obtidas as seqÃÃncias nucleotÃdicas dos genes da capa proteica, Rep e de toda a regiÃo intergÃnica, em um total de 2.130 nucleotÃdeos. A anÃlise comparativa das seqÃÃncias revelou que, em geral, o GOANPL possui relacionamento genÃtico distante com begomovÃrus da Ãsia, Europa e Ãfrica sendo mais prÃximo das espÃcies do Brasil, particularmente, com os begomovÃrus identificados em Minas Gerais (TRMV) e no Distrito Federal (DF-BR2). Com este Ãltimo, apresentou alta homologia em todo o genoma podendo vir a constituir, com o mesmo, uma nova espÃcie. A determinaÃÃo do cÃrculo de hospedeiros do GO-ANPL foi realizada inoculando-se 46 espÃcies vegetais pertencentes a nove famÃlias botÃnicas, sob duas modalidades de inoculaÃÃo: mecÃnica e com a mosca branca. Constatou-se que o GO-ANPL infecta, preferencialmente, plantas da famÃlia Solanaceae como Nicotiana benthamiana, Datura stramonium e Nicandra physalodes. O nÃmero de espÃcies infectadas com o inseto vetor foi superior ao obtido pela inoculaÃÃo mecÃnica e diferiu dos resultados obtidos para outros isolados de begomovÃrus de tomate no Brasil. Os testes foram todos confirmados com hibridizaÃÃo com sondas moleculares, em \"dot blot\"No estudo da relaÃÃo vÃrus-vetor, foram investigados o perÃodo de acesso de aquisiÃÃo do vÃrus (PAA), o perÃodo de acesso de inoculaÃÃo do vÃrus (PAI), e o perÃodo de latÃncia do vÃrus na fase adulta do vetor, empregando-se cinco moscas/planta de tomate \'Santa Clara\' em todos os tratamentos. Para a definiÃÃo do PAA e do PAI, foram testados nove diferentes perÃodos de tempo: 0,25, 0,5, 1, 2, 4, 8, 16, 20 e 24 horas. Nos testes para determinaÃÃo do PAA, apÃs cada um desses perÃodos seguiu-se uma inoculaÃÃo de 48 horas e para definiÃÃo do PAI, antes de cada perÃodo antecedeu-se um perÃodo de acesso de aquisiÃÃo fixo de 72 horas. Constatou-se que o PAA mÃnimo da mosca branca foi de apenas 0,25 hora, com o qual foram obtidas 6% de plantas infectadas. O percentual de plantas aumentou de 6 para 65% com a extensÃo do PAA de 0,25 para 24 horas. Com relaÃÃo ao perÃodo de acesso de inoculaÃÃo do vÃrus, foram registrados 18% de plantas infectadas com o PAI de 0,5 hora. O percentual elevou-se para 67% quando 24 horas de PAI foram concedidos. Valores isolados de 90 e 100% na transmissÃo viral, tambÃm foram observados. O tÃrmino do perÃodo latente do vÃrus no vetor ocorreu 16h apÃs a aquisiÃÃo do mesmo em planta infectada, considerando os 3% de infecÃÃo observados nas plantas inoculadas. Os dados obtidos indicam que a interaÃÃo vÃrus-vetor à estabelecida desde a fase inicial de desenvolvimento do inseto. Como parte do estudo dessa interaÃÃo, avaliou-se a presenÃa do begomovÃrus GO-ANPL em todas as fases de desenvolvimento do inseto vetor (ovo, 1 ao 4 Ãnstar e adulto) na planta infectada, em adultos com diferentes PAA, na progÃnie de fÃmeas virulÃferas e em adultos cujos estÃgios ninfais desenvolveram-se em tomateiro infectado. A tÃcnica PCR foi empregada para a detecÃÃo do GO-ANPL em mais de 2.500 espÃcimens testados. O vÃrus foi detectado em ninfas do 1 ao 4 Ãnstar que se alimentaram em plantas de tomate infectada, contudo, em ovos provenientes de avirulÃferas, os quais foram ovipositados em planta infectada e coletados apÃs sete dias, o vÃrus nÃo foi detectado. A transmissÃo à progÃnie foi constatada pela detecÃÃo do vÃrus em ovos, ninfas e adultos que se desenvolveram em planta nÃo hospedeira do vÃrus. A transmissÃo transestadial ocorreu com Ãndice elevado e, ao lado da transmissÃo à progÃnie, indica que a retenÃÃo do vÃrus à uma etapa importante da interaÃÃo vÃrusâvetor. A transmissÃo do vÃrus para mudas de tomate, a partir de adultos da progÃnie de fÃmeas virulÃferas, nÃo foi constatada. Contudo, transmissÃo para tomateiro em um percentual de 33% foi verificado nos casos em que a inoculaÃÃo das plantas foi realizada pelos adultos que retiveram o vÃrus da sua fase imatura (transestadial) / The whitefly-transmitted viruses from the family Geminiviridae, genus Begomovirus, have been reported as an economically important pathogen group that affect important crops in tropical and subtropical countries. Since the beginning of the 1980 decade, the occurrence of the whitefly associated to Begomovirus infection has drastically increased worldwide. In Brazil, these pathogens have been responsable for severe economical losses in tomato (Lycopersicon esculentum) orchards and the production has hampered since 1994. In this work, infected tomato plants showing symptoms, such as mosaic, intervein clearing, leaf curling and growth reduction were collected in tomato orchards in AnÃpolis, State of GoiÃs. The virus was identified as a member of the genus Begomovirus by PCR reaction, using specific primers to amplify fragments of A and B components of the virus DNA genome. The Chapter I of this thesis presents the results of the molecular characterization of the virus and the Chapter II shows the determination of its host range and the relationship with its natural vector Bemisia argentifolii. The virus isolate denoted GO-ANPL was cloned and partially sequenced. Part of the sequenced genome (2.180 nucleotides long) corresponded to the coat protein and Rep genes and comprised the entire intergenic region. Sequence comparison revealed that the GO-ANPL isolate is distantly related to the begomoviruses found in Asia, Europe and Africa, and it is related to other begomoviruses reported in Brazil. The virus isolate showed to be more closely related to viruses found in the State of Minas Gerais (TRMV isolate) and in the Federal District (isolate DF-Br2). The highest homology was observed with the isolate DF-Br2 and it may represent a new specie of the genus Begomovirus. In order to determine the virus host range, 46 plant species from nine different botanical families were mechanically and using the virus vector inoculated. The GO-ANPL isolate preferentially infected plants of the family Solanaceae as Nicotiana benthamiana, Datura stramonium and Nicandra physalodes. The number of infected plants was higher when they were inoculated by the virus vector, and the results were distinct from those obtained for other begomoviruses reported in Brazil. Viruses infections were all confirmed by dot blot hybridization using specific molecular probes to the virus. 4 To study virus/vector interaction, the acquisition access period (AAP), inoculation access period (IAP), and the latent period were determined transfering five whiteflies per plant and using tomato cv. Santa Clara as the host. For the AAP and IAP, nine different time periods were tested: 0.25, 0.5, 1, 2, 4, 8, 16, 20 and 24 h. The minimal AAP determined was 0.25 h, after which, 6% of the tested plants became infected. The number of infected plants increased to 65% with an AAP of24h.Afteran IAP of 0.5 h, 18% of the plants were infected and their number increased to 67% after an IAP of 24 hours. The latent period was considered to be 16 h, after which, 3% of the inoculated plants became infected. The results of AAP, IAP and latent period seem to indicate an early interaction between virus and vector starting at early stages of vector development. The presence of the GOANPL was determined in all stages of the vector (eggs, 1st to 4th instar and adults) in infected plants, in adults under different AAPs, in the progenies of viruliferous females, and in adults originated from nymphs developed from infected plants. More than 2.500 insects were tested by PCR to detect the GO-ANPL isolate. The virus was detected in nymphs from the 1st to 4th instar that had fed in infected plants and no virus was found in eggs from aviruliferous female that had been laid in infected plants. Transmission to the progenies was observed, since the virus was detected in all stages of insect development from eggs to adults. High level transmission was also observed in newly emerged adults that had acess to virus-infected plants as immatures. This fact, in addition to the transmission to the progenies, suggests that virus retention is an important part of virus/vector interaction. No transmission was observed from adults originated from viruliferous females. However, 33% of virus transmission was obtained when adults that retained virus from their early larval stages were employed

Το βακτήριο Wolbachia είναι ένα ενδοκυττάριο και μητρικά κληρονομούμενο συμβιωτικό βακτήριο. Ανήκει στην ομοταξία των Alphaproteobacteria και την τάξη των Rickettsiales. Αποτελεί ίσως τον πιο διαδεδομένο ενδοκυττάριο συμβιωτικό οργανισμό στον πλανήτη, καθώς έχει εντοπιστεί μέχρι στιγμής σε πληθώρα αρθροπόδων και νηματωδών της φιλαρίασης. Πρόσφατες μελέτες εκτιμούν ότι πάνω από το 40% των ειδών αρθροπόδων είναι μολυσμένα με το βακτήριο Wolbachia. Το συμβιωτικό αυτό βακτήριο επηρεάζει τις βιολογικές λειτουργίες και ιδιότητες των ξενιστών του και είναι υπεύθυνο για μια σειρά αναπαραγωγικών ανωμαλιών, όπως η κυτταροπλασματική ασυμβατότητα, η παρθενογένεση, η θανάτωση των αρσενικών εμβρύων και η θηλυκοποίηση. Τα μοναδικά αυτά βιολογικά χαρακτηριστικά του βακτηρίου Wolbachia προσελκύουν όλο και περισσότερο το ενδιαφέρον διαφόρων ερευνητών τόσο για το ρόλο του βακτηρίου σε εξελικτικές διαδικασίες (κυρίως ειδογένεση) όσο και για τη χρησιμοποίησή του σε περιβαλλοντικά φιλικές εφαρμογές καταπολέμησης οργανισμών που είναι επιβλαβείς στους τομείς του γεωργικού και δασικού περιβάλλοντος, και της υγείας. Τα είδη του γένους Glossina (Diptera: Glossinidae), γνωστά και ως μύγες τσε-τσε, αποτελούν ξενιστές του βακτηρίου Wolbachia. Η μύγα τσε-τσε είναι ο σημαντικότερος φορέας των παθογόνων τρυπανοσωμάτων στην τροπική Αφρική, τα οποία προκαλούν την ασθένεια του ύπνου (sleeping sickness) στον άνθρωπο και την αντίστοιχη τρυπανοσωμίαση, γνωστή ως nagana, στα ζώα. Η χρησιμοποίηση του βακτηρίου Wolbachia σε μεθόδους βιολογικής καταπολέμησης της μύγας τσε-τσε προαπαιτεί την πλήρη γνώση της γενετικής του ταυτότητας και των αλληλεπιδράσεων του με το ξενιστή. Προς την κατεύθυνση αυτή, και στα πλαίσια της παρούσας διατριβής, πραγματοποιήθηκε η ανίχνευση του συμβιωτικού βακτηρίου Wolbachia σε περισσότερα από 5300 άτομα από φυσικούς και εργαστηριακούς πληθυσμούς 11 διαφορετικών ειδών μύγας τσε-τσε από 13 Αφρικανικές χώρες. Τα αποτελέσματα έδειξαν τεράστια απόκλιση της παρουσίας του βακτηρίου τόσο μεταξύ ειδών όσο και μεταξύ πληθυσμών του ίδιου είδους. Επίσης, πραγματοποιήθηκε ο γενετικός χαρακτηρισμός των στελεχών Wolbachia από συνολικά 29 αντιπροσωπευτικά δείγματα διαφόρων πληθυσμών και ειδών μύγας τσε-τσε, ενώ σε αρκετά από αυτά παρατηρήθηκαν πολλαπλά στελέχη του βακτηρίου. Διαπιστώθηκε εντυπωσιακή γενετική ποικιλότητα στελεχών Wolbachia που απαντούν στα διάφορα είδη μύγας τσε-τσε καθώς και ασυμφωνία μεταξύ των φυλογενειών των στελεχών Wolbachia και των μυγών τσε-τσε ξενιστών της, γεγονός που σημαίνει οριζόντια μετακίνηση του συμβιωτικού βακτηρίου κατά την εξέλιξη. Επιπρόσθετα, εντοπίστηκαν για πρώτη φορά εκτεταμένα γεγονότα οριζόντιας μεταφοράς βακτηριακών γονιδίων στο γονιδίωμα τριών ειδών μύγας τσε-τσε: στο Glossina morsitans morsitans, Glossina pallidipes και Glossina austeni. Από εξελικτικής σκοπιάς, κρίσιμα ερωτήματα προκύπτουν από τα παραπάνω ευρήματα, και πιο συγκεκριμένα σχετικά με: την προέλευση-μηχανισμό αυτών των γεγονότων οριζόντιας μεταφοράς, τον χρονικό προσδιορισμό τους, τον πιθανό ρόλο τους σε διαδικασίες ειδογένεσης και την επιλεκτική εμφάνισή τους σε ορισμένα μόνο είδη Glossina π.χ. στo υποείδos Glossina morsitans centralis που είναι πολύ συγγενικό του Glossina morsitans morsitans δεν παρατηρήθηκε το φαινόμενο. Εξίσου σημαντική και επιβεβλημένη κρίνεται η διεξοδική διερεύνηση του ενδεχομένου τα βακτηριακά γονίδια που ενσωματώθηκαν στο ευκαρυωτικό γονιδίωμα της μύγας τσε-τσε να ευθύνονται για την έκφραση νέων λειτουργιών-ιδιοτήτων (ή να μεταβάλλουν τις ήδη υπάρχουσες), ιδίως μάλιστα εάν αυτές συνδέονται με την αποδοτικότητα μετάδοσης της νόσου της τρυπανοσωμίασης μέσω του φορέα της, δηλαδή της μύγας τσε-τσε. Τέλος, διαπιστώθηκε πιθανή αρνητική συσχέτιση της παρουσίας του βακτηρίου Wolbachia με τον παθογόνο ιό Salivary Gland hypertrophy Virus (SGHV), γεγονός που συζητείται στα πλαίσια βιολογικών εφαρμογών καταπολέμησης του εντόμου-φορέα και της τρυπανοσωμίασης. Παράλληλα, μεγάλο ενδιαφέρον παρουσιάζει η προοπτική χρησιμοποίησης του βακτηρίου Wolbachia για τη βιολογική καταπολέμηση εντόμων αγροτικής ή /και περιβαλλοντικής σημασίας, όπως είναι οι αφίδες και η καρπόκαψα καστανιάς. Το γεγονός αυτό προϋποθέτει την ανίχνευση και τη γενετική ταυτοποίηση του βακτηρίου σε φυσικούς πληθυσμούς εντόμων. Στα πλαίσια της παρούσας διατριβής πραγματοποιήθηκε ανίχνευση και χαρακτηρισμός του βακτηρίου Wolbachia σε 78 συνολικά άτομα από 22 είδη αφίδων, από 26 φυσικούς πληθυσμούς από την Ελλάδα. Από αυτούς τους 26 πληθυσμούς, μόλις οι 4 βρέθηκαν να είναι μολυσμένοι με το βακτήριο Wolbachia και συγκεκριμένα πληθυσμοί των ειδών: Aphis fabae, Aphis hederae, Metopolophium dirhodum και Baizongia pistaciae. Τα αποτελέσματα αυτά δείχνουν για πρώτη φορά ότι η παρουσία του βακτηρίου Wolbachia στις αφίδες είναι πιθανά πιο διαδεδομένη από ότι προέκυπτε από προηγούμενες μελέτες. Επίσης, μελετήθηκε η ανίχνευση και ο χαρακτηρισμός του βακτηρίου Wolbachia στα είδη Cydia splendana, Cydia fagiglandana και Pammene fasciana. Το βακτήριο Wolbachia ανιχνεύθηκε για πρώτη φορά στα συγκεκριμένα είδη και μάλιστα διαπιστώθηκε ότι η συχνότητα εμφάνισής του ποικίλει τόσο μεταξύ των δύο ειδών Cydia όσο και μεταξύ των πληθυσμών του κάθε είδους. Στο είδος Pammene fasciana, το βακτήριο ανιχνεύθηκε σε όλα τα άτομα που μελετήθηκαν. Τα αποτελέσματα της παρούσας διατριβής συζητούνται από τη σκοπιά τόσο της οικολογικής και εξελικτικής σημασίας τους όσο και της προοπτικής χρησιμοποίησης του συμβιωτικού βακτηρίου Wolbachia για τον πληθυσμιακό έλεγχο επιβλαβών εντόμων όπως οι μύγες τσε-τσε, οι αφίδες και η καρπόκαψα καστανιάς. / Wolbachia is an intracellular and maternally inherited symbiotic bacterium that belongs to the class of Alphaproteobacteria and the order of Rickettsiales. It is the most ubiquitous intracellular symbiotic organism of the planet, since it has been estimated that over 40% of insect species, in addition to filarial nematodes, crustaceans, and arachnids are infected with Wolbachia. In arthropods Wolbachia affects the biological functions and properties of its hosts and it is responsible for a number of reproductive abnormalities, such as cytoplasmic incompatibility (CI), thelytokous parthenogenesis, feminization of genetic males and male killing. These unique biological characteristics of Wolbachia are attracting the interest of various researchers for: (a) decyphering the role of Wolbachia in evolutionary processes (mainly speciation), and (b) for its use in environmentally friendly applications for the control of agricultural pests and disease vectors. The species of genus Glossina (Diptera: Glossinidae) known as tsetse flies, have been found to be infected with Wolbachia. Tsetse flies are the sole vectors of pathogenic trypanosomes in tropical Africa, causing the “sleeping sickness” in humans and the “nagana” in animals. The potential use of Wolbachia for the control of tsetse flies, prerequisite a thorough knowledge of its genetic identity and the interactions with the host. To further characterize the prevalence of Wolbachia in tsetse flies an extensive screen of more than 5300 specimens from natural and laboratory populations of 11 different Glossina species originating from 13 African countries was carried out. Our results indicated a huge divergence in the prevalence of Wolbachia, both among the species and among populations of the same species. Further characterization by MLST and wsp genotyping was carried out for the Wolbachia strains of 29 representative populations and species of tsetse flies. An impressive genetic diversity of Wolbachia strains in tsetse flies was revealed. Interestingly, disconcordance between the phylogeny of Wolbachia and that of the tsetse flies was observed, suggesting horizontal transmission of Wolbachia during the evolution. Moreover, extended horizontal gene transfer events were detected for first time in Glossina morsitans morsitans, Glossina pallidipes και Glossina austeni. These results raise critical questions concerning: (a) the origin/mechanism of these horizontal gene transfer events, (b) their temporal determination, (c) their potential role as agents of speciation and (d) their selective appearance in only some Glossina species e.g in the subspecies Glossina morsitans centralis which is closely related with Glossina morsitans morsitans the phenomenon was not observed. Equally important will be to examine if genes from the chromosomal insertions were potentially expressed and examine if these genes are associated with the vectorial capacity of tsetse flies for the trypanosoma transmission. Finally, a negative correlation between the presence of Wolbachia with the Salivary Gland Hypertrophy Virus (SGHV) was identified. This is further discussed in the context of biological applications for control of tsetse fly-vector and trypanosomiasis. Finally in this thesis, the detection and characterization of Wolbachia in 78 specimens of 22 aphids species, from 26 natural populations, from Greece was examined. Only 4 out of 26 populations were found to be infected with Wolbachia, and specifically the species: Aphis fabae, Aphis hederae, Metopolophium dirhodum και Baizongia pistaciae. These results indicated that the presence of Wolbachia in aphids is probably more prevalent than it was derived from previous studies. Also, detection and characterization of Wolbachia in the Cydia splendana, Cydia fagiglandana and Pammene fasciana was carried out. Wolbachia was detected for first time in these species, and it was found that the prevalence of Wolbachia varies between the two species of Cydia and among populations of each species, with the infection in Pammene fasciana being fixed. At the end the ecological and evolutionary importance of Wolbachia, together with the use of the bacterium for the population control of harmful insects like tsetse flies, aphids and moths is further discussed.

Insgesamt 1746 Kleinsäuger aus den Familien Muridae (Murinae, Arvicolinae) und Soricidae aus dem Naturschutzgebiet ”Großer Hakel” (Sachsen-Anhalt) und der Tagebaufolgelandschaft ”Phönix-Ost und Rusendorf” Meuselwitz (Thüringen) wurden auf einen Befall mit Capillaria hepatica und Metazestoden von Bandwürmern (Cyclophyllida) untersucht. Das Tiermaterial stammte aus genehmigten faunistischen Untersuchungen aus den Jahren 1993 bis 1997 in Zusammenarbeit mit der Universität Halle und dem Naturkundemuseum "Mauritianum" Altenburg. Alle Mäuse wurden seziert und der Brust- und Bauchraum einschließlich aller Organoberflächen, der Subkutis, des Gehirns und der Leber untersucht. Eine Altersbestimmung der Wirte erfolgte bei den untersuchten Rötelmäusen (Clethrionomys glareolus). Erstmals in Deutschland konnte im Hakel ein stabiles Endemiegebiet von Capillaria hepatica bei Wildmäusen nachgewiesen werden. Die aus dem ”Großen Hakel” stammenden Gelbhals- (Apodemus flavicollis) und Rötelmäuse wiesen Befallshäufigkeiten von 8,5 bzw. 15,1 % auf, die Eizahlen pro Leber lagen zwischen 67 und 3 600 000. Weibliche Mäuse zeigten eine höhere Befallshäufigkeit als männliche Mäuse. Bei den Rötelmäusen konnte ein Anstieg der Befallshäufigkeit von 5,8 % der bis zu 3 Monate alten bis auf 28,6 % der bis zu einem Jahr alten Tiere beobachtet werden. Patente Infektionen waren erst in der Altersgruppe 3-6 Monate nachzuweisen. In dem Untersuchungsgebiet Meuselwitz war Capillaria hepatica bei den untersuchten 1069 Muridae und Soricidae nicht nachweisbar. Eine aktuelle Übersicht der weltweit in 53 Ländern festgestellten 137 Wirtsarten aus 25 Säugetierfamilien von Capillaria hepatica wurde zusammengestellt. Die Familie Muridae stellt mit 83 Arten die bedeutendste Wirtsgruppe dar. Bisher wurde über 56 Capillaria-hepatica-Infektionen beim Menschen (davon 39 Kinder) aus 18 Ländern berichtet. Die Leitsymptome der Erkrankung beim Menschen sind intermittierendes Fieber, Hepatomegalie, Leukozytose mit hochgradiger, persistierender Eosinophilie, Anämie, Hypergammaglobulinämie und Hypoalbuminämie. Die Serumaktivitäten von AST, ALT und LDH sind erhöht. Die Diagnose der zum Teil tödlich verlaufenden Erkrankung ist intra vitam bisher nur durch Leberbiopsie oder Laparotomie möglich. Einzelne Versuche mit serologischen Tests scheinen erfolgversprechend. Die Einzelnachweise von Capillaria hepatica bei Mensch, Hase und Sumpfbiber in Deutschland (Bayern, Sachsen und Sachsen-Anhalt) sind als Hinweise auf bestehende Endemiegebiete zu werten. Aufgrund der weiteren Verbreitung und der diagnostischen Probleme kann von einer höheren Gefährdung des Menschen (insbesondere Kleinkinder) und der Haustiere durch den Zoonoseerreger Capillaria hepatica ausgegangen werden. Bei 10,5 % aller untersuchten Mäuse wurden Metazestoden gefunden. Die Rötelmaus wies insgesamt mit durchschnittlich 23,5 % (Meuselwitz 30,2 %, Hakel 15,1 %) die signifikant höchsten Befallshäufigkeiten mit Metazestoden auf. Insgesamt konnten bei Muridae und Soricidae in Sachsen-Anhalt und Thüringen Metazestoden von 8 Bandwurmgattungen bzw. -arten (Cladotaenia globifera, Mesocestoides spp., T. crassiceps, T. martis martis, T. martis americana, T. mustelae, T. polyacantha, T. taeniaeformis) nachgewiesen werden. Die breiteste Metazestodenfauna mit insgesamt 7 Arten wurde bei der Feldmaus (Microtus arvalis), nur jeweils eine Metazestodenart dagegen bei Brandmaus (Apodemus agrarius), Zwergmaus (Micromys minutus), Feldspitzmaus (Crocidura leucodon) und Waldspitzmaus (Sorex araneus) gefunden. Die Zwergspitzmaus (Sorex minutus) war nicht von Metazestoden befallen. Eine deutliche Wirtsspezifität (Feldmaus) konnte für T.-crassiceps- und T.-polyacantha-Metazestoden festgestellt werden. Im Gebiet Meuselwitz dominierten bei Muridae Metazestoden von T. mustelae (Befallshäufigkeit 9,3 %) sowie von T. martis martis (Befallshäufigkeit 6,4 %), im Hakel von T. martis martis (Befallshäufigkeit 2,5 %) sowie T. mustelae (Befallshäufigkeit 2,2 %). Während in Meuselwitz die höchsten Befallshäufigkeiten mit Metazestoden von T. mustelae (24,7 %) bei der Rötelmaus und von T. martis martis (13 %) bei der Gelbhalsmaus vorlagen, waren im Hakel die Rötelmäuse am häufigsten mit T.-mustelae- (8,2 %) und T.-martis-martis- Metazestoden (4,8 %) befallen. Mit zunehmendem Alter der Rötelmäuse stieg die Befallshäufigkeit mit Metazestoden bei dieser Tierart an. Rötelmäuse unter einem Alter von 2 Monaten waren noch nicht von Metazestoden befallen. Infektionen mit 2 Metazestodenarten traten erstmals bei 4 Monate alten Rötelmäusen auf, bei zwei Tieren im Alter von 9 bzw. 12 Monaten wurden Infektionen mit 3 Metazestodenarten (Cladotaenia globifera + T. martis americana + T. mustelae; Cladotaenia globifera + T. martis martis + T. mustelae) nachgewiesen. Bei insgesamt 10 Muriden konnten Mischinfektionen mit Capillaria hepatica und Metazestoden von Bandwürmern festgestellt werden. Bei Mäusen der Familie Soricidae sind ausschließlich Metazestoden von Cladotaenia globifera gefunden worden. Erstnachweise für Deutschland stellen Funde der Metazestoden von Cladotaenia globifera bei der Feldspitzmaus, T. martis americana bei der Rötelmaus, T. mustelae bei Erd- und Zwergmaus und T. polyacantha bei der Waldmaus dar. Das erste Mal in Europa konnten T.-martis-americana-Metazestoden bei der Feldmaus gefunden werden. Eine wichtige Einflußgröße auf die Metazestodenfauna war das Aufeinandertreffen von End- und Zwischenwirt in bestimmten Biotopen. / The occurrence of Capillaria hepatica and metacestodes of Cyclophillida was investigated in 1746 small mammals of the families Muridae (Murinae, Arvicolinae) and Soricidae from the nature reserve ”Grosser Hakel” (Saxony-Anhalt) and the former open-cast mining area "Phoenix-Ost and Rusendorf" Meuselwitz (Thuringia). The animals came from approved faunistic surveys in co-operation with the University of Halle and the natural history museum ”Mauritianum” Altenburg. All mice were sectioned and the thoracic as well as the abdominal cavity including all organ surfaces, subcutaneous tissue, brain and liver were examined. The age of all bank voles (Clethrionomys glareolus) was determined. In the nature reserve "Grosser Hakel"an stable endemic area of Capillaria hepatica in wild mice could be detected for the first time in Germany. The percentage of yellow-necked mice (Apodemus flavicollis) infected with Capillaria hepatica in that area was 8.5 %, the percentage of bank voles infected with Capillaria hepatica in that area reached 15.1 % respectively. The number of eggs per liver ranged from 67 to 3,600,000. The proportion of infected mice was higher in female than in male mice. In bank voles the frequency of infection increased with age (from 5.8 % in the age of 3 months to 28.6 % in the age of one year). Patent infections were first detected in the age group of 3 to 6 month. No Capillaria hepatica could be found in 1069 Muridae and Soricidae examined in the Meuselwitz area. A current survey of the world-wide occurrence of Capillaria hepatica in 137 hosts of 25 mammal families was prepared. The family of Muridae (with 83 species) is the most important host group. Up to now 56 Capillaria-hepatica-infections in humans (including 39 children) from 18 different countries were reported. Major symptoms in humans are intermittent fever, hepatomegaly, leucocytosis with severe, persistent eosinophilia, anaemia, hypergammaglobulinaemia and hypoalbuminaemia. The serum activities of AST, ALT and LDH are elevated. Intra-vitam diagnosis of this partly lethal disease is only possible by liver biopsy or laparatomy. First serological tests are promising. Sporadic detection of Capillaria hepatica in humans, hares and nutria in Germany (Bavaria, Saxony and Saxony-Anhalt) can be regarded as an indication of existing endemic areas. A higher risk of Capillaria-hepatica-infection in humans (especially in small children) and domestic animals can be assumed on the basis of the wide distribution and the diagnostic problems. Metacestodes were found in 10.5 % of all examined mice. The bank voles showed the significantly highest rate of infection with 23.5 % (Meuselwitz 30.2 % and Hakel 15.1 %). Altogether metacestodes of 8 tapeworm genuses (Cladotaenia globifera, Mesocestoides spp., T. crassiceps, T. martis martis, T. martis americana, T. mustelae, T. polyacantha, T. taeniaeformis) could be detected in Muridae and Soricidae in Saxony-Anhalt and Thuringia. The broadest metacestode-fauna (with 7 species) was found in the common vole (Microtus arvalis). Only one metacestode-species was detected in the stripped field mouse (Apodemus agrarius), the harvest mouse (Micromys minutus), the bicoloured whitetoothed shrew (Crocidura leucodon) and the eurasion common shrew (Sorex araneus). The pygmy shrew (Sorex minutus) was not infected by metacestodes. A distinct host specificity (in the common vole) could be established for T. crassiceps and T. polyacantha. Metacestodes of T. mustelae (infection rate 9.3 %) and T. martis martis (infection rate 6.4 %) dominated in Muridae of the Meuselwitz area. In the Hakel area T. martis martis (infection rate 2.5 %) and T. mustelae (infection rate 2.2 %) dominated as well. Whereas metacestodes of T. mustelae occurred in the bank vole with an infection rate of 24.7 % and T. martis martis in yellow-necked mice with an infection rate of 13.0 % in the Meuselwitz area, T. mustelae occurred in bank voles with an infection rate of 8.2 % and T. martis martis in yellow-necked mice with an infection rate of 4.8 % in the Hakel area. The infection rate of bank voles with metacestodes increased with age. No metacestodes were found in bank voles younger than 2 month of age. Infection with 2 different metacestode-species occurred in bank voles for the first time at the age of 4 month. 3 metacestode-species were found in 2 animals at the age of 9 to 12 months (Cladotaenia globifera + T. martis americana + T. mustelae; Cladotaenia globifera + T. martis martis + T. mustelae). In 10 Muridae occurred a mixed infection with Capillaria hepatica and metacestodes of tapeworms. In mice of the Soricidae-family only metacestodes from Cladotaenia globifera could be found. For the first time in Germany were detected metacestodes of Cladotaenia globifera in the bicoloured whitetoothed shrew, of T. martis americana in bank voles, of T. mustelae in the common field vole and the harvest mouse and of T. polyacantha in the wood mouse. For the first time in Europe T. martis americana-metacestodes could be detected in the common vole. Of high importance to the metacestode-fauna was the encounter of final host and intermediate host in certain biotopes.

Portable languages and distributed paradigms have driven a wave of new applications and processing models. One of the most promising, certainly from its early marketing, but disappointing (from its limited uptake)is the mobile agent execution and data processing model. Mobile agents are autonomous programs which can move around a heterogeneous network such as the Internet, crossing through a number of different security domains, and perform some work at each visited destination as partial completion of a mission for their agent user. Despite their promise as a technology and paradigm to drive global electronic services (i.e.any Internet-driven-and-delivered service, not solely e-commerce related activities), their up take on the Internet has been very limited. Chief among the reasons for the paradigm's practical under-achievement is there is no ubiquitous frame work for using Internet mobile agents, and non-trivial security concerns abound for the two major stake holders (mobile agent users and mobile agent platform owners). While both stake holders have security concerns with the dangers of the mobile agent processing model, most investigators in the field are of the opinion that protecting mobile agents from malicious agent platforms is more problematic than protecting agent platforms from malicious mobile agents. Traditional cryptographic mechanisms are not well-suited to counter the bulk of the threats associated with the mobile agent paradigm due to the untrusted hosting of an agent and its intended autonomous, flexible movement and processing. In our investigation, we identified that the large majority of the research undertaken on mobile agent security to date has taken a micro-level perspective. By this we mean research focused solely on either of the two major stakeholders, and even then often only on improving measures to address one security issue dear to the stake holder - for example mobile agent privacy (for agent users) or access control to platform resources (for mobile agent platform owners). We decided to take a more encompassing, higher-level approach in tackling mobile agent security issues. In this endeavour, we developed the beginnings of an infrastructural-approach to not only reduce the security concerns of both major stakeholders, but bring them transparently to a working relationship. Strategic utilisation of both existing distributed system trusted-third parties (TTPs) and novel mobile agent paradigm-specific TTPs are fundamental in the infrastructural framework we have devised. Besides designing an application and language independent frame work for supporting a large-scale Internet mobile agent network, our Mobile Agent Secure Hub Infrastructure (MASHIn) proposal encompasses support for flexible access control to agent platform resources. A reliable means to track the location and processing times of autonomous Internet mobile agents is discussed, withfault-tolerant handling support to work around unexpected processing delays. Secure,highly-effective (incomparison to existing mechanisms) strategies for providing mobile agent privacy, execution integrity, and stake holder confidence scores were devised - all which fit comfortably within the MASHIn framework. We have deliberately considered the interests - withoutbias -of both stake holders when designing our solutions. In relation to mobile agent execution integrity, we devised a new criteria for assessing the robustness of existing execution integrity schemes. Whilst none of the existing schemes analysed met a large number of our desired properties for a robust scheme, we identified that the objectives of Hohl's reference states scheme were most admirable - particularly real - time in - mission execution integrity checking. Subsequently, we revised Hohl's reference states protocols to fit in the MASHIn framework, and were able to overcome not only the two major limitations identified in his scheme, but also meet all of our desired properties for a robust execution integrity scheme (given an acceptable decrease in processing effiency). The MASHIn offers a promising new perspective for future mobile agent security research and indeed a new frame work for enabling safe and autonomous Internet mobile agents. Just as an economy cannot thrive without diligent care given to micro and macro-level issues, we do not see the security prospects of mobile agents (and ultimately the prospects of the mobile agent paradigm) advancing without diligent research on both levels.

Insgesamt 1746 Kleinsäuger aus den Familien Muridae (Murinae, Arvicolinae) und Soricidae aus dem Naturschutzgebiet ”Großer Hakel” (Sachsen-Anhalt) und der Tagebaufolgelandschaft ”Phönix-Ost und Rusendorf” Meuselwitz (Thüringen) wurden auf einen Befall mit Capillaria hepatica und Metazestoden von Bandwürmern (Cyclophyllida) untersucht. Das Tiermaterial stammte aus genehmigten faunistischen Untersuchungen aus den Jahren 1993 bis 1997 in Zusammenarbeit mit der Universität Halle und dem Naturkundemuseum "Mauritianum" Altenburg. Alle Mäuse wurden seziert und der Brust- und Bauchraum einschließlich aller Organoberflächen, der Subkutis, des Gehirns und der Leber untersucht. Eine Altersbestimmung der Wirte erfolgte bei den untersuchten Rötelmäusen (Clethrionomys glareolus). Erstmals in Deutschland konnte im Hakel ein stabiles Endemiegebiet von Capillaria hepatica bei Wildmäusen nachgewiesen werden. Die aus dem ”Großen Hakel” stammenden Gelbhals- (Apodemus flavicollis) und Rötelmäuse wiesen Befallshäufigkeiten von 8,5 bzw. 15,1 % auf, die Eizahlen pro Leber lagen zwischen 67 und 3 600 000. Weibliche Mäuse zeigten eine höhere Befallshäufigkeit als männliche Mäuse. Bei den Rötelmäusen konnte ein Anstieg der Befallshäufigkeit von 5,8 % der bis zu 3 Monate alten bis auf 28,6 % der bis zu einem Jahr alten Tiere beobachtet werden. Patente Infektionen waren erst in der Altersgruppe 3-6 Monate nachzuweisen. In dem Untersuchungsgebiet Meuselwitz war Capillaria hepatica bei den untersuchten 1069 Muridae und Soricidae nicht nachweisbar. Eine aktuelle Übersicht der weltweit in 53 Ländern festgestellten 137 Wirtsarten aus 25 Säugetierfamilien von Capillaria hepatica wurde zusammengestellt. Die Familie Muridae stellt mit 83 Arten die bedeutendste Wirtsgruppe dar. Bisher wurde über 56 Capillaria-hepatica-Infektionen beim Menschen (davon 39 Kinder) aus 18 Ländern berichtet. Die Leitsymptome der Erkrankung beim Menschen sind intermittierendes Fieber, Hepatomegalie, Leukozytose mit hochgradiger, persistierender Eosinophilie, Anämie, Hypergammaglobulinämie und Hypoalbuminämie. Die Serumaktivitäten von AST, ALT und LDH sind erhöht. Die Diagnose der zum Teil tödlich verlaufenden Erkrankung ist intra vitam bisher nur durch Leberbiopsie oder Laparotomie möglich. Einzelne Versuche mit serologischen Tests scheinen erfolgversprechend. Die Einzelnachweise von Capillaria hepatica bei Mensch, Hase und Sumpfbiber in Deutschland (Bayern, Sachsen und Sachsen-Anhalt) sind als Hinweise auf bestehende Endemiegebiete zu werten. Aufgrund der weiteren Verbreitung und der diagnostischen Probleme kann von einer höheren Gefährdung des Menschen (insbesondere Kleinkinder) und der Haustiere durch den Zoonoseerreger Capillaria hepatica ausgegangen werden. Bei 10,5 % aller untersuchten Mäuse wurden Metazestoden gefunden. Die Rötelmaus wies insgesamt mit durchschnittlich 23,5 % (Meuselwitz 30,2 %, Hakel 15,1 %) die signifikant höchsten Befallshäufigkeiten mit Metazestoden auf. Insgesamt konnten bei Muridae und Soricidae in Sachsen-Anhalt und Thüringen Metazestoden von 8 Bandwurmgattungen bzw. -arten (Cladotaenia globifera, Mesocestoides spp., T. crassiceps, T. martis martis, T. martis americana, T. mustelae, T. polyacantha, T. taeniaeformis) nachgewiesen werden. Die breiteste Metazestodenfauna mit insgesamt 7 Arten wurde bei der Feldmaus (Microtus arvalis), nur jeweils eine Metazestodenart dagegen bei Brandmaus (Apodemus agrarius), Zwergmaus (Micromys minutus), Feldspitzmaus (Crocidura leucodon) und Waldspitzmaus (Sorex araneus) gefunden. Die Zwergspitzmaus (Sorex minutus) war nicht von Metazestoden befallen. Eine deutliche Wirtsspezifität (Feldmaus) konnte für T.-crassiceps- und T.-polyacantha-Metazestoden festgestellt werden. Im Gebiet Meuselwitz dominierten bei Muridae Metazestoden von T. mustelae (Befallshäufigkeit 9,3 %) sowie von T. martis martis (Befallshäufigkeit 6,4 %), im Hakel von T. martis martis (Befallshäufigkeit 2,5 %) sowie T. mustelae (Befallshäufigkeit 2,2 %). Während in Meuselwitz die höchsten Befallshäufigkeiten mit Metazestoden von T. mustelae (24,7 %) bei der Rötelmaus und von T. martis martis (13 %) bei der Gelbhalsmaus vorlagen, waren im Hakel die Rötelmäuse am häufigsten mit T.-mustelae- (8,2 %) und T.-martis-martis- Metazestoden (4,8 %) befallen. Mit zunehmendem Alter der Rötelmäuse stieg die Befallshäufigkeit mit Metazestoden bei dieser Tierart an. Rötelmäuse unter einem Alter von 2 Monaten waren noch nicht von Metazestoden befallen. Infektionen mit 2 Metazestodenarten traten erstmals bei 4 Monate alten Rötelmäusen auf, bei zwei Tieren im Alter von 9 bzw. 12 Monaten wurden Infektionen mit 3 Metazestodenarten (Cladotaenia globifera + T. martis americana + T. mustelae; Cladotaenia globifera + T. martis martis + T. mustelae) nachgewiesen. Bei insgesamt 10 Muriden konnten Mischinfektionen mit Capillaria hepatica und Metazestoden von Bandwürmern festgestellt werden. Bei Mäusen der Familie Soricidae sind ausschließlich Metazestoden von Cladotaenia globifera gefunden worden. Erstnachweise für Deutschland stellen Funde der Metazestoden von Cladotaenia globifera bei der Feldspitzmaus, T. martis americana bei der Rötelmaus, T. mustelae bei Erd- und Zwergmaus und T. polyacantha bei der Waldmaus dar. Das erste Mal in Europa konnten T.-martis-americana-Metazestoden bei der Feldmaus gefunden werden. Eine wichtige Einflußgröße auf die Metazestodenfauna war das Aufeinandertreffen von End- und Zwischenwirt in bestimmten Biotopen. / The occurrence of Capillaria hepatica and metacestodes of Cyclophillida was investigated in 1746 small mammals of the families Muridae (Murinae, Arvicolinae) and Soricidae from the nature reserve ”Grosser Hakel” (Saxony-Anhalt) and the former open-cast mining area "Phoenix-Ost and Rusendorf" Meuselwitz (Thuringia). The animals came from approved faunistic surveys in co-operation with the University of Halle and the natural history museum ”Mauritianum” Altenburg. All mice were sectioned and the thoracic as well as the abdominal cavity including all organ surfaces, subcutaneous tissue, brain and liver were examined. The age of all bank voles (Clethrionomys glareolus) was determined. In the nature reserve "Grosser Hakel"an stable endemic area of Capillaria hepatica in wild mice could be detected for the first time in Germany. The percentage of yellow-necked mice (Apodemus flavicollis) infected with Capillaria hepatica in that area was 8.5 %, the percentage of bank voles infected with Capillaria hepatica in that area reached 15.1 % respectively. The number of eggs per liver ranged from 67 to 3,600,000. The proportion of infected mice was higher in female than in male mice. In bank voles the frequency of infection increased with age (from 5.8 % in the age of 3 months to 28.6 % in the age of one year). Patent infections were first detected in the age group of 3 to 6 month. No Capillaria hepatica could be found in 1069 Muridae and Soricidae examined in the Meuselwitz area. A current survey of the world-wide occurrence of Capillaria hepatica in 137 hosts of 25 mammal families was prepared. The family of Muridae (with 83 species) is the most important host group. Up to now 56 Capillaria-hepatica-infections in humans (including 39 children) from 18 different countries were reported. Major symptoms in humans are intermittent fever, hepatomegaly, leucocytosis with severe, persistent eosinophilia, anaemia, hypergammaglobulinaemia and hypoalbuminaemia. The serum activities of AST, ALT and LDH are elevated. Intra-vitam diagnosis of this partly lethal disease is only possible by liver biopsy or laparatomy. First serological tests are promising. Sporadic detection of Capillaria hepatica in humans, hares and nutria in Germany (Bavaria, Saxony and Saxony-Anhalt) can be regarded as an indication of existing endemic areas. A higher risk of Capillaria-hepatica-infection in humans (especially in small children) and domestic animals can be assumed on the basis of the wide distribution and the diagnostic problems. Metacestodes were found in 10.5 % of all examined mice. The bank voles showed the significantly highest rate of infection with 23.5 % (Meuselwitz 30.2 % and Hakel 15.1 %). Altogether metacestodes of 8 tapeworm genuses (Cladotaenia globifera, Mesocestoides spp., T. crassiceps, T. martis martis, T. martis americana, T. mustelae, T. polyacantha, T. taeniaeformis) could be detected in Muridae and Soricidae in Saxony-Anhalt and Thuringia. The broadest metacestode-fauna (with 7 species) was found in the common vole (Microtus arvalis). Only one metacestode-species was detected in the stripped field mouse (Apodemus agrarius), the harvest mouse (Micromys minutus), the bicoloured whitetoothed shrew (Crocidura leucodon) and the eurasion common shrew (Sorex araneus). The pygmy shrew (Sorex minutus) was not infected by metacestodes. A distinct host specificity (in the common vole) could be established for T. crassiceps and T. polyacantha. Metacestodes of T. mustelae (infection rate 9.3 %) and T. martis martis (infection rate 6.4 %) dominated in Muridae of the Meuselwitz area. In the Hakel area T. martis martis (infection rate 2.5 %) and T. mustelae (infection rate 2.2 %) dominated as well. Whereas metacestodes of T. mustelae occurred in the bank vole with an infection rate of 24.7 % and T. martis martis in yellow-necked mice with an infection rate of 13.0 % in the Meuselwitz area, T. mustelae occurred in bank voles with an infection rate of 8.2 % and T. martis martis in yellow-necked mice with an infection rate of 4.8 % in the Hakel area. The infection rate of bank voles with metacestodes increased with age. No metacestodes were found in bank voles younger than 2 month of age. Infection with 2 different metacestode-species occurred in bank voles for the first time at the age of 4 month. 3 metacestode-species were found in 2 animals at the age of 9 to 12 months (Cladotaenia globifera + T. martis americana + T. mustelae; Cladotaenia globifera + T. martis martis + T. mustelae). In 10 Muridae occurred a mixed infection with Capillaria hepatica and metacestodes of tapeworms. In mice of the Soricidae-family only metacestodes from Cladotaenia globifera could be found. For the first time in Germany were detected metacestodes of Cladotaenia globifera in the bicoloured whitetoothed shrew, of T. martis americana in bank voles, of T. mustelae in the common field vole and the harvest mouse and of T. polyacantha in the wood mouse. For the first time in Europe T. martis americana-metacestodes could be detected in the common vole. Of high importance to the metacestode-fauna was the encounter of final host and intermediate host in certain biotopes.