Made available in DSpace on 2014-08-20T14:31:29Z (GMT). No. of bitstreams: 1 dissertacao_fabiana_fedatto_bernardon.pdf: 2564105 bytes, checksum: 3adada5c7a15fdd6272eae15d9df82e8 (MD5) Previous issue date: 2013-02-27 / The Ardeidae family is composed of more than 60 species, being one of the largest and most representative families of birds with characteristics adapted to wetlands. Rio Grande do Sul is characterized by presenting ecosystems which harbor a unique diversity of waders, where there is the record of 13 species of Ardeidae. Due to lack of information on the diversity of helminths in the Ardeidae family in Rio Grande do Sul, the work was developed with the goal of identifying the helminthfauna of nine species of Ardeidae and determine the parameters of prevalence, mean abundance and mean intensity. Were examined 30 birds of the Ardeidae family (Pelecaniformes), Ardea alba , Ardea cocoi, Butorides striata, Bubulcus ibis, Egretta thula, Ixobrychus involucris, Nycticorax nycticorax , Syrigma sibilatrix e Tigrisoma lineatum from the natural environment of the cities of Pelotas, Capão do Leão e Rio Grande, RS, Brazil. The birds were necropsied to collect helminths, prepared in accordance with the protocols used for each group and identified. As a result there was obtained species of Trematoda, Nematoda and Acanthocephala and their parasitological parameters as follow below: Trematoda: Digenea, Amphimerus interruptus (P=3,3%; AM=0,1; IM= 3,0), Apharyngostrigea ardearum (P=40%; AM=18,6; IM= 46,6), Ascocotyle sp. (P=33,3%; AM=88,4; IM= 265,3), Clinostomum complanatum (P=30%; AM=1,1; IM= 3,8), Episthmium proximum (P=23,3%; AM=1,0; IM=4,2), Ithyclinostomum dimorphum (P=6,6%; AM=0,1; IM=2,5), Nephrostomum limai (P=10%; AM= 0,3; IM=3,6), Ribeiroia insignis (P=10%; AM=2,8; IM=28,0 ) and Stomylotrema sp. (P=3,3%; AM=0,03; IM=1,0) belonging to eight families: Nematoda: Contracaecum microcephalum (P=80%; AM=15,1; IM=18,8), Desportesius invaginatus (P=43,3%; AM=2,76; IM=6,3), Desmidocercella ardeae (P=16,6%; AM=1,3; IM=8,0), Eustrongylides sp. (P=13,3%; AM=1,3; IM=10,2) and Baruscapillaria sp. (P=10%; AM=0,5; IM=5,0). Acanthocephala: Acanthocephalus sp. (Echinorhynchidae) (P=3,33%; AM=0,03; IM=1,0), Andracantha sp. (P=33,3%; AM=15,2; IM=45,8), Arhythmorhynchus sp. (P=6,66%; AM=0,16; IM=2,5) and Polymorphus sp. (Plagiorhynchidae) (P=13,3%; AM=1,3; IM=10,2). Tigrisoma lineatum was the only negative for all groups Ixobrychus involucris was negative for the presence of Trematoda and Bubulcus ibis negative for acanthocephalans. The Trematoda, Nematoda and Acanthocephala mentioned above are for the first time recorded in the Ardeidae family in Rio Grande do Sul in Brazil, some of the hosts and their helminth characterizes first occurrence. We have found insulated proglottids of cestodes in small and large intestine in some birds, but could not identify them. / A família Ardeidae é composta por mais de 60 espécies sendo uma das maiores e mais representativas famílias de aves com características adaptadas às áreas úmidas. O Rio Grande do Sul caracteriza-se por apresentar ecossistemas que abrigam uma diversidade ímpar de aves pernaltas onde há o registro de 13 espécies de ardeídeos. Devido a escassez de informações sobre a diversidade de helmintos em Ardeidae no Rio Grande do Sul, desenvolveu-se o trabalho com o objetivo de identificar a helmintofauna de nove espécies de ardeídeos e determinar a os parâmetros de prevalência, abundância e intensidade médias. Foram examinados 30 aves. Ardea alba, Ardea cocoi, Butorides striata, Bubulcus ibis, Egretta thula, Ixobrychus involucris, Nycticorax nycticorax, Syrigma sibilatrix e Tigrisoma lineatum, provenientes de ambiente natural dos municípios de Pelotas, Capão do Leão e Rio Grande RS, Brasil. As aves foram necropsiadas para a coleta dos helmintos, preparadas de acordo com os protocolos utilizados para cada grupo e identificadas. Como resultado obteve-se espécies de trematódeos, nematóides e acantocéfalos e seus parâmetros parasitológicos como seguem a seguir: Trematoda: Digenea, Amphimerus interruptus (P=3,3%; AM=0,1 ;IM=3,0), Apharyngostrigea ardearum (P=40%; AM=18,6; IM= 46,6), Ascocotyle sp. (P=33,3%; AM=88,4; IM= 265,3), Clinostomum complanatum (P=30%; AM=1,1; IM=3,8), Episthmium proximum (P=23,3%; AM=1,0; IM=4,2), Ithyclinostomum dimorphum (P=6,6%; AM=0,1; IM=2,5), Nephrostomum limai (P=10%; AM= 0,3; IM=3,6), Ribeiroia insignis (P=10%; AM=2,8; IM=28,0) e Stomylotrema sp. (P=3,3%; AM=0,03; IM=1,0) pertencentes a oito famílias; Nematoda: Contracaecum microcephalum (P=80%; AM=15,1;IM=18,8),Desportesius invaginatus(P=43,3%; AM=2,76; IM=6,3), Desmidocercella ardeae (P=16,6%; AM=1,3; IM=8,0), Eustrongylides sp. (P=13,3%; AM=1,3; IM=10,2) e Baruscapillaria sp. (P=10%; AM=0,5; IM=5,0). Acanthocephala: Acanthocephalus sp. (Echinorhynchidae) (P=3,33%; AM=0,03; IM=1,0), Andracantha sp. (P=33,3%; AM=15,2; IM=45,8), Arhythmorhynchus sp. (P=6,66%; AM=0,16; IM=2,5) e Polymorphus sp. (Plagiorhynchidae) (P=13,3%; AM=1,3; IM=10,2). Tigrisoma lineatum foi o único ardeídeo negativo para todos os grupos, enquanto que Ixobrychus involucris quanto à presença de trematódeos e Bubulcus ibis quanto à presença de acantocéfalos. Os trematódeos, nematóides e acantocéfalos citados anteriormente são pela primeira vez registrados em ardeídos no Rio Grande do Sul. No Brasil, alguns dos hospedeiros e respectivos helmintos constituem primeira ocorrência. Foram encontradas proglotes isoladas de cestóides no intestino delgado e grosso em algumas aves, porém não foi possível identificá-las.

1. Overview Schistosomes have achieved first position among parasitic helminths, because some of them are the etiological agents of a serious human parasitic disease, schistosomiasis, which affects over 200 million people in tropical and subtropical countries (WHO, 2001). Other schistosomatids, such as the bird flukes of the genus Trichobilharzia, have also implications for human health. Although they can mature only in specific hosts (birds), their invasive larvae - cercariae - are able to penetrate also human skin due to chemical signals similar to those present on bird skin (Haas and van de Roemer 1998). Repeated infections result in an inflammatory reaction of the skin called cercarial dermatitis. Due to the increasing number of outbreaks all around the world, cercarial dermatitis is cons disease (Kolářová 2007idered as re-emerging ; Larsen et al. 2004). Among schistosomes, Trichobilharzia regenti is the only species described so far having a unique migration route within vertebrate hosts: after penetration of the skin, the invasive larvae enter peripheral nerves and continue via the spinal cord and central nervous system to the nasal cavity of birds, causing neuromotor disorders or paralyses of birds and even experimental mammals (Hrádková...

From simple beginnings, when only one host was required, numerous parasitic organisms have evolved complex life-cycles involving two or more host species. For example, trematode parasites reproduce in vertebrates, their definitive host, but their current life cycle also typically involves two intermediate hosts that were added during the course of evolution. Vertebrates are often considered to be the ancestral hosts of trematodes although other scenarios exist. While multi-host life cycles are observed in distantly related groups of parasites, their evolution remains largely unexplored. In trematodes, while recent phylogenetic studies have shed light on the sequence along which the different hosts were incorporated in the cycle, conditions that favoured the evolution of such complex life cycles can only be hypothesized. However, one opportunity to understand the force shaping the evolution of complex life cycles is provided by the few trematode species in which the classical three-host cycle facultatively reverts to a shorter cycle (i.e. life cycle abbreviation). In this study, the effects of different environmental factors on the life history strategy of the trematode Coitocaecum parvum were investigated using laboratory and field studies. C. parvum is able to abbreviate its life cycle from three to two hosts by maturing early (i.e. progenesis) and producing eggs inside the second intermediate host; both life history strategies occur simultaneously in C. parvum populations. Environmental factors such as predator densities should strongly influence parasite life history strategies. In fact, this study shows that laboratory reared Coitocaecum parvum adopt preferentially the normal three-host cycle when chemical cues from the definitive host are added to their environment, while the shorter cycle is favoured when these cues are absent. However, in nature, multiple environmental factors are likely to be perceived by parasites. Consequently, C. parvum�s ability to adapt its developmental strategy to definitive host densities may be confounded by the complex combination of various environmental parameters. Within-host competition between parasites sharing a common host is also likely to influence individual life history strategies. Parasites could then use alternative life strategies to adaptively respond to intraspecific and interspecific competition. Indeed, this study found that C. parvum preferentially adopts the abbreviated cycle in the presence of competitors. However, in interspecific competition, C. parvum�s strategy also depends upon the competitor species, possibly influenced by the other species� transmission route. Furthermore, intensity of intraspecific competition proved to constrain C. parvum�s ability to use the abbreviated life cycle. Finally, genetic relatedness between co-infecting C. parvum individuals seems to affect parasite life strategy through kin selection: closely related individuals are more likely to adopt the same developmental strategy, when they share a host, than unrelated ones. C. parvum individuals adopting the abbreviated cycle are enclosed within a cyst in their intermediate host and must produce eggs by self-fertilization, the most severe case of inbreeding. It was hypothesized that their offspring would have reduced fitness due to inbreeding depression, therefore selecting against the shorter cycle. However, this study found no difference in the survival and infection success of offspring produced through the abbreviated and normal cycles. Furthermore, no evidence for a genetic basis of life cycle abbreviation was detected: the same proportion of offspring from both reproductive strategies adopted the shorter life cycle. The work in this thesis provides evidence that although life cycle abbreviation provides Coitocaecum parvum with a viable alternative life strategy, numerous factors promote or restrict the adoption of this strategy. While this life history strategy has no detectable effect on parasite fitness, both environmental parameters and within-host competition affect C. parvum life-history strategies, alternatively selecting for either the shorter or normal life cycle. Overall, the complexity of the parasite environment could maintain both developmental strategies in C. parvum populations and, on a broader scale, could have influenced the evolution of complex life cycles in parasites.

Graduation date: 1954

From simple beginnings, when only one host was required, numerous parasitic organisms have evolved complex life-cycles involving two or more host species. For example, trematode parasites reproduce in vertebrates, their definitive host, but their current life cycle also typically involves two intermediate hosts that were added during the course of evolution. Vertebrates are often considered to be the ancestral hosts of trematodes although other scenarios exist. While multi-host life cycles are observed in distantly related groups of parasites, their evolution remains largely unexplored. In trematodes, while recent phylogenetic studies have shed light on the sequence along which the different hosts were incorporated in the cycle, conditions that favoured the evolution of such complex life cycles can only be hypothesized. However, one opportunity to understand the force shaping the evolution of complex life cycles is provided by the few trematode species in which the classical three-host cycle facultatively reverts to a shorter cycle (i.e. life cycle abbreviation). In this study, the effects of different environmental factors on the life history strategy of the trematode Coitocaecum parvum were investigated using laboratory and field studies. C. parvum is able to abbreviate its life cycle from three to two hosts by maturing early (i.e. progenesis) and producing eggs inside the second intermediate host; both life history strategies occur simultaneously in C. parvum populations. Environmental factors such as predator densities should strongly influence parasite life history strategies. In fact, this study shows that laboratory reared Coitocaecum parvum adopt preferentially the normal three-host cycle when chemical cues from the definitive host are added to their environment, while the shorter cycle is favoured when these cues are absent. However, in nature, multiple environmental factors are likely to be perceived by parasites. Consequently, C. parvum�s ability to adapt its developmental strategy to definitive host densities may be confounded by the complex combination of various environmental parameters. Within-host competition between parasites sharing a common host is also likely to influence individual life history strategies. Parasites could then use alternative life strategies to adaptively respond to intraspecific and interspecific competition. Indeed, this study found that C. parvum preferentially adopts the abbreviated cycle in the presence of competitors. However, in interspecific competition, C. parvum�s strategy also depends upon the competitor species, possibly influenced by the other species� transmission route. Furthermore, intensity of intraspecific competition proved to constrain C. parvum�s ability to use the abbreviated life cycle. Finally, genetic relatedness between co-infecting C. parvum individuals seems to affect parasite life strategy through kin selection: closely related individuals are more likely to adopt the same developmental strategy, when they share a host, than unrelated ones. C. parvum individuals adopting the abbreviated cycle are enclosed within a cyst in their intermediate host and must produce eggs by self-fertilization, the most severe case of inbreeding. It was hypothesized that their offspring would have reduced fitness due to inbreeding depression, therefore selecting against the shorter cycle. However, this study found no difference in the survival and infection success of offspring produced through the abbreviated and normal cycles. Furthermore, no evidence for a genetic basis of life cycle abbreviation was detected: the same proportion of offspring from both reproductive strategies adopted the shorter life cycle. The work in this thesis provides evidence that although life cycle abbreviation provides Coitocaecum parvum with a viable alternative life strategy, numerous factors promote or restrict the adoption of this strategy. While this life history strategy has no detectable effect on parasite fitness, both environmental parameters and within-host competition affect C. parvum life-history strategies, alternatively selecting for either the shorter or normal life cycle. Overall, the complexity of the parasite environment could maintain both developmental strategies in C. parvum populations and, on a broader scale, could have influenced the evolution of complex life cycles in parasites.

Thesis (Ph. D.)--Illinois State University, 1977. / Title from title page screen, viewed Jan. 4, 2005. Dissertation Committee: Harry W. Huizinga, H. Hetzel, M. Nadakavukaren, A. Richardson, E. Willis. Includes bibliographical references (leaves 181-195) and abstract. Also available in print.

M.Sc. (Zoology) / Please refer to full text to view abstract

The objective of the present study is then limited to investigate the parasitic fauna of marine fishes from Ensenada, Baja California, and to compile in a single manuscript all data (Host-Parasite list, Parasite-Host list, and distribution of parasites) on digenea previously reported from the Mexican Pacific and the Gulf of California.

Examination of 154 fishes representing 45 species from the Jamaican north shore yielded 43 species of digenea in 12 families.

Cerithidea california is examined to determine the fecundity of the parasitic trematode species in its gonad. Five species of trematodes are studied (Cloacitrema michiganensis, Euhaplorchis californiensis, Parorchis acanthus, Himasthia rhigedana, and Acanthoraryphium sp.). Their fecundity is determined by direct counts of rediae and estimation of the cercarial population. Correlations are shown for trematode numbers and snail size. Incidences of infection are given with regard to site, snail size, and trematode species. Comparison is made between infection ratios of C. californica and another marsh snail, Batillaria zonalis.