RT Dissertation/Thesis T1 Morphological and molecular studies on cerebral and non-cerebral coenurosis in sheep and goats A1 Christodoulopoulos,Georgios WP 2018/02/27 AB This study explores the causative agent of cerebral and non-cerebral coenurosis in sheep and goats. Cases of non-cerebral coenurosis from a wide geographical range in Africa and western Asia are investigated, and the causative agents are compared to cerebral coenurus cysts from gid cases collected from Greece, where cerebral coenurosis is common but where non-cerebral coenurosis has never been described. The study includes a field and a laboratory-experimental component and provides answers to research questions such as: (i) the presence or absence of non-cerebral coenurosis in sheep; (ii) the description of non-cerebral coenurosis in the intermediate host (sheep and goats); and (iii) the phylogenetic resolution of the T. multiceps cluster and a possible explanation why non-cerebral coenurosis has never been described from some geographical areas. In the field component, a total of 90,415 slaughtered sheep and 2,284 slaughtered goats from abattoirs in the United Arab Emirates (UAE) and Egypt, originating from various tropical and subtropical countries, including India, Pakistan, Iran, Oman, Sudan, Somalia, and Ethiopia, were examined for non-cerebral coenurosis. The field component also included the collection of cerebral coenurus cysts from 20 sheep and 6 goats with cerebral coenurosis and originating from continental Greece and vicinity. Four studies were conducted in the laboratory-experimental component: (1) a morphological study of the characteristics of non-cerebral coenurus cysts and their clusters and protoscolices, (2) a morphological comparison of the rostellar hooks of the collected cerebral and non-cerebral coenurus cysts, (3) a morphological comparison of adult worms produced in dogs experimentally infected with protoscolices from cerebral and non-cerebral cysts of sheep and goats, and (4) a molecular analysis of three partial mitochondrial genes (nad1, cox1, and 12S rRNA) of the above isolates of cerebral and non-cerebral cysts collected in Greece, UAE, and Egypt. The prevalence of non-cerebral coenurosis was 1.75% in goats and only 0.008% in sheep. The only abnormalities observed in the infected goats were large single cysts detected by palpation in thigh muscles and higher serum aspartate aminotransferase (AST) activity. The cysts were found in various muscles and attached to the kidneys, omentum, and heart; they were surrounded by a fibrous, semi-opaque, cloudy-white membrane containing a single coenurus in all cases. The volume of the cysts, the number of the clusters of protoscolices, and the number of protoscolices were similar in sheep and goats. Seventy-six non-cerebral coenurus cysts were collected from goats. The number of protoscolices was significantly positively correlated with the volume of cysts (b = 6.37 > 5; R-Sq = 89.4%; P = 0.000), and the number of clusters was significantly positively correlated with the number of protoscolices (b = 25.13 > 1; R-Sq = 79.8%; P = 0.000), indicating positive allometric growth. The number of clusters was significantly positively correlated with the volume of cysts (b = 0.25 < 0.5; R-Sq = 69.4%; P = 0.000), indicating however negative allometric growth. The biological significance of these allometries is not known, but the parasite may be investing its resources more in the growth of protoscolices, less in the growth of cyst volume, and even less in the number of clusters. Our morphological studies of the rostellar hooks of protoscolices from the cerebral and non-cerebral cysts and the adult worms produced experimentally in dogs did not indicate host-adapted differences (sheep or goats). In contrast, the parasites produced by cerebral and non-cerebral cysts showed clear morphological differences. Most measurements of the hooks and proglottids differed significantly, but the shape of the small hooks, the distribution of the testes in the mature proglottids, and the appearance of the coils of the vas deferens were the most distinct characters. These morphological differences, albeit between the parasites produced by cerebral and non-cerebral cysts, fell within the range of variation of T. multiceps. The phylogenetic analysis of the mitochondrial haplotypes produced three distinct clusters: one cluster including both cerebral isolates from Greece and non-cerebral isolates from tropical and subtropical countries, and two clusters including only cerebral isolates from Greece. The majority of the non-cerebral specimens clustered together but did not form a monophyletic group. No monophyletic groups were observed based on geography, although specimens from the same region tended to cluster. The recorded clusters indicated high intraspecific diversity. The results of this study support the association between T. multiceps variability and the geographical origin of the isolates and lead us to propose a reformulated hypothesis for the existence of cerebral and non-cerebral forms. Our phylogenetic analysis suggests that the development of cerebral coenuri in sheep may be an ancestral property of T. multiceps and the main mode the parasite uses to complete its life cycle. All variants are therefore able to cause cerebral coenurosis in sheep, but only some variants, predominantly from one genetic cluster, acquired the additional capacity to affect the brain of other species (goats and cattle) or to produce non-cerebral forms, mostly in goats and more rarely in sheep. Our phylogenetic analysis therefore clearly indicates a molecular basis for non-cerebral pathogenicity in some variants of T. multiceps. Specific biosecurity actions should therefore be enforced in areas where non-cerebral coenurosis does not occur to prevent the introduction of T. multiceps variants with such pathogenicity. K1 Taenia multiceps K1 Taenia gaigeri, Taenia skrjabini K1 Zerebralen Coenurose K1 nicht-zerebralen Coenurose K1 Mitochondriale Gene K1 Schafe K1 Ziegen PP Hohenheim PB Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim UL http://opus.uni-hohenheim.de/volltexte/2018/1446