A multifaceted Schistosoma haematobium study aimed at assessing five different diagnostic techniques of surveillance was conducted. Their use in varying operational circumstances with particular reference to Primary Health Care was conducted in three areas of varying prevalence of disease namely; Mpolweni Mission (44.1%), Empangeni (30.3%) and Verulam (72.0%), KwaZulu-Natal, South Africa. This study incorporated both theoretical and applied components. The theoretical components included freshwater snail surveys, review of literature of S. haematobium diagnostic techniques and an assessment of five diagnostic techniques with particular emphasis on diagnostic performance and cost analyses. Added to these components was migration and the assessment of the prevalence of disease amongst occupants of informal settlements in and around the greater Pietermaritzburg city centre. The applied component included the initiation of a holistic S. haematobium control programme based along the World Health Organisation Guidelines. The study provided insight into several of the countries health issues relevant to both schistosomiasis and other diseases and highlighted weaknesses that may hinder the successful implementation of the current National Framework for Parasite Control. The presence of urban schistosomiasis was noted for the first time in the city of Pietermaritzburg. The present schistosomiasis distribution could be influenced by the rural-urban migration that is impacting upon major metropolitan areas. Without intermediate host snail surveys and schistosomiasis prevalence surveys amongst members of the population, the real geographic distribution of the disease will not be known. The diagnostic methods that were compared included sedimentation, filtration, three brands of chemical urinalysis strips, urine colour scales and an indirect questionnaire. Sensitivity, specificity, positive predictive, negative predictive and efficiency values were determined. Using these values, diagnostic performance ranges were established. The ranges were influenced by the cut-off values used, technique and prevalence and intensity of infection of the study area. The chemical urinalysis strips at cut-off 10erythrocyes/μl (73.7% - 93.2%) were highly sensitive whereas urine colour scales (97.1% - 99.4%) and indirect questionnaire (80.4% - 90.3%) were highly specific. The relationship between the community prevalence rates measured by all five techniques varied significantly. A cost-analysis of the techniques/sample demonstrated a wide price range (20c - R4.32). Therefore their use would be dictated more by the availability of funding than by any operational advantages each individual technique may have demonstrated. Within the public health services a need for: (1) staff training programmes, (2) core staff based within the PHC system that is dedicated to parasite control and (3) a strengthening of infrastructure was demonstrated. These may be achieved via workshops, improved communication, education courses, specific time allocation to parasite programmes i.e. parasite week, project co-ordinators and the designation of tasks. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

No description available.

Despite more than half a century of international research on schistosomiasis control, this disease remains a public health concern in many Third World countries. Four to five percent of the world's population is estimated to be infected. In South Africa, bilharzia is prevalent in rural communities which lack piped water and adequate sanitation. Transport and treatment costs limit access to Western medication. In the last decade, plant molluscicides have received considerable attention in the ongoing search for cheaper alternatives to chemotherapy and synthetic molluscicides. Plant molluscicides may be locally harvested, extracted and applied for the control of the snail host. This approach is based on a philosophy of self-reliance and self-determination. However, such involvement presupposes recognition of the infection as a real problem. Before selecting and evaluating plants for molluscicidal activity, it was first necessary to establish the status of schistosomiasis in rural communities, and the willingness of community members to become involved in control efforts. Field surveys showed that rural South African communities do not share the indifference of the past health-care system towards schistosomiasis in this country. Concern for the disease was matched by a prevalence of 75.14% for S. haematobium in the study area. The potential of the South African flora to provide suitable molluscicidal candidates has never been systematically assessed . As random screening is costly and is historically of limited success, a need has existed for the development of an objective selection procedure . A simple scoring system was devised, based on the criteria for "good" plant molluscicides as defined by the World Health Organization (WHO). Three plant species were subsequently selected for further intensive evaluation: Warburgia salutaris, Gardenia thunbergia and Apodytes dimidiata. Initially, the activity of crude aqueous suspensions of all three candidates was investigated, since this application form is the most practical for use in a rural situation. Further, the stability of extracts under changing physical and chemical conditions was assessed, as were t he effects of molluscicides on a wide range of to the toxicity of aqueous suspensions, cultivation potential, medicinal value, stability, and toxicity to non-target organisms. Studies on the mode of action of the three plant extracts revealed that death occurred via distinct physiological pathways; this despite the similarities in clinical symptoms. Such is the complexity of snail physiology that until more intensive neurological investigations are undertaken, the mechanisms of molluscicidal action can only be inferred. Chemical compounds responsible for activity were identified from Apodytes dimidiata; genipin, a monoterpene, was one such active constituent. Although not previously recorded as molluscicidal, earlier workers have isolated genipin from Genipa americana and Gardenia jasminoides. Notably, this compound has not yet been isolated from Gardenia thunbergia. Further activity in A. dimidiata extracts appeared to be the result of a synergistic effect, potentially involving (S)(-) ethyllactate. Research on mammalian toxicity, and registration procedures for plant molluscicides in South Africa should be prioritized for further investigation, before pilot field trials are initiated. Almost thirty years have passed since the first reports on the activity of Phyto!acca dodecandra. Although more than 1000 plant species have since been tested world-wide, it appears that no plant molluscicide has ever been endorsed by the WHO. More concerted efforts are necessary to ensure that appropriate molluscicidal technologies are provided to infected communities. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1994.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 180-211).

Thesis (M. S. in Chemistry)--Vanderbilt University, Dec. 2009. / Title from title screen. Includes bibliographical references.

published_or_final_version / Microbiology / Master / Master of Philosophy

An ethological study was undertaken in two primary schools in Natal to assess the effect of schistosome infections on the ordinary behaviour of schoolchildren in endemic areas. The following topics are discussed :- 1. The life cycle of the parasite, the possibility of an evolved tolerance of it, the likely limits of such tolerance, the possibility of selective exposure of certain kinds of children to the parasite, and the role of severity of infection in impairment. 2. Appropriate measures for investigating the impairment of the human host centring around the measurement of activity in the context of social interaction. 3. An ethological approach to evaluating human response to disease. Results indicate that there is selective exposure of more active, sociable children to the disease. In low-level infections of both Schistosoma haematobium and Schistosoma mansoni there is little evidence of a drop in energetic activity under normal conditions. In subjects with higher egg counts or simultaneous infections with both schistosomes, activity levels drop generally, and especially under hot, humid weather conditions where the drop in activity is greater than that for control subjects. This work throws doubt on earlier studies indicating that the parasite had no behavioural effect on humans: these studies did not control for selective exposure and may have used methods of low sensitivity and doubtful relevance to everyday life. / Thesis (Ph.D.)-University of Natal, 1981.

Iron is a trace element required for a range of metabolic reactions in virtually all living organisms. Studies of prokaryotes, plants, yeast, and vertebrates have established detailed information on iron uptake and the role iron plays in metabolic processes. Iron is an essential growth requirement of schistosomes in vitro and schistosomes also express the highly conserved iron storage protein ferritin. However, studies into how this iron is taken up by the parasite have been neglected. This study aims to identify molecules involved in iron uptake and homeostasis in the human parasite Schistosoma japonicum. I have characterised two isoforms of a divalent metal transporter (DMT), a membrane bound protein of schistosomes. These DMTs have significant homology to the mammalian DMT1, the primary ferrous iron uptake protein of the intestinal brush border. Both schistosome isoforms displayed functional iron uptake by rescuing growth in a yeast strain deficient in iron uptake (fet3fet4). Interestingly schistosome DMT1 was localised to the tegument and not the gastrodermis of adult parasites, suggesting surface mediated iron uptake across the tegument. In physiological conditions, iron is abundant as largely insoluble ferric iron and hence ferric reductases are an essential component of iron uptake, reducing iron to the soluble ferrous form. Cytochromes b561 (Cyts-b561) are a family of ascorbate reducing transmembrane proteins found in most eukaryotic cells. Recent observations that Cyts-b561 may be involved in iron metabolism have opened new perspectives for their physiological function. Here, I have identified a new member of the cytochrome b561 family in Schistosoma japonicum that localises to the tegument of this trematode. Expression of the SjCytb561 in a Saccharomyces cerevisiae mutant that lacks plasma membrane ferrireductase activity (fre1fre2) was able to rescue the growth defect in iron deficient conditions, suggesting involvement in iron metabolism. Plasma membrane ferrireductase activities were also quantified using intact transformed yeast cells. These data further support the hypothesised tegumental uptake of host iron. Further, I have identified a putative schistosome transferrin. In mammals, transferrin is a glycoprotein responsible for binding and transporting iron in the bloodstream and delivering iron into cells via a specific transferrin receptor. Preliminary characterisation of the schistosome transferrin sequence has revealed it does not contain all the conserved amino acid residues associated with iron binding, with conservation seen only in the C-terminal lobe, not in both the N and C-lobes observed in mammalian transferrins. This difference makes it unclear whether the schistosome transferrin shares functional homology with its mammalian counterpart. In addition, no transferrin receptor has been identified to support an iron trafficking and uptake function, nor would this function be expected in an acoelomate organism. Further characterisation and localisation of this protein is required to elucidate its biological significance and function. The tegumental location of both the SjDMT1 and the SjCytb561 for the uptake of host iron make it possible to consider these proteins as potential vaccine candidates. A preliminary vaccination study with these proteins elicited only low to moderate protection from infection, and further studies are required to fully assess their potential. The data presented in this thesis provide evidence for surface-mediated uptake of iron by adult schistosomes, and represent the first characterisation of iron uptake proteins in any helminths. These studies show a novel method of iron uptake in schistosomes, and contribute to our understanding of how these parasites are able to survive and thrive by scavenging nutrients, in this case iron, from the host organism.

Orientador: Eliana Maria Zanotti-Magalhães / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-14T15:49:19Z (GMT). No. of bitstreams: 1 Zuim_NadiaReginaBorim_D.pdf: 2561919 bytes, checksum: 9793a302a9d0497fca07cd4cc0bf9f23 (MD5) Previous issue date: 2009 / Resumo: Na esquistossomose mansônica, a reação granulomatosa que ocorre em torno dos ovos de S. mansoni constitui a principal manifestação patogênica. A resposta granulomatosa mostrou ser específica para os ovos de cada uma das três principais espécies de Schistosoma que parasitam o homem ( S. mansoni, S. haematobium e S. japonicum). A reação granulomatosa que se desenvolve ao redor dos ovos de S. mansoni é estágio específico. Os objetivos deste trabalho foram estudar a evolução das reações granulomatosas em torno dos ovos de S. mansoni das linhagens BH e SJ, verificar se a reação granulomatosa em torno do ovo de S. mansoni é linhagem específica e avaliar a patogenia do S. mansoni da linhagem isolada do Jardim São Domingos (Campinas, SP), realizando um estudo comparativo com as linhagens BH e SJ. Para o estudo da evolução das reações granulomatosas, dois grupos de camundongos foram inoculados pela veia caudal com ovos maduros das linhagens BH e SJ e mortos após 1, 8, 15 e 34 dias. Para o estudo da especificidade da reação granulomatosa dois grupos de camundongos foram infectados por cercárias de S. mansoni BH e na 8ª semana de infecção um grupo foi inoculado pela veia caudal com ovos BH e outro grupo com ovos SJ. Os camundongos foram mortos após 1, 8, 15 e 34 dias após a inoculação dos ovos. Os parâmetros analisados foram: número de granulomas por área de tecido pulmonar e hepático e tamanho das reações granulomatosas. Para avaliar a patogenia do S. mansoni da linhagem isolada no Jardim São Domingos (Campinas, SP) e realizar um estudo comparativo com as linhagens BH e SJ foram constituídos três grupos de camundongos infectados e na oitava semana de infecção, os camundongos sobreviventes foram sacrificados para recuperação de vermes. Os parâmetros verificados foram: número de cercárias penetrantes; número de ovos eliminados nas fezes; número de esquistossomos no sistema porta-mesentérico; número de granulomas presentes no fígado, baço, intestino (cólon ascendente), pâncreas e pulmão, área dos granulomas observados no fígado e intestino e tamanho dos ovos de S. mansoni. Os resultados obtidos permitiram concluir que a reação granulomatosa em torno dos ovos de S. mansoni das linhagens BH e SJ, mostrou ser linhagem específica, indicando haver identidade parcial na resposta granulomatosa entre os ovos das duas linhagens. Os dados obtidos no estudo da linhagem SD de S. mansoni indicaram ser esta linhagem, a mais patogênica das linhagens já descritas, que tem B. tenagophila como hospedeira do trematódeo. Nos camundongos infectados com esta linhagem foi observada maior recuperação de vermes (48,62%) em relação ao número de cercárias penetrantes ( =64,50), maior número de granulomas na maioria das vísceras, maior reação granulomatosa em torno dos ovos do trematódeo e maior tamanho dos ovos (155,60 µm x 64,63 µm). De importância epidemiológica, foi a constatação de elevado número de ovos eliminados nas fezes, apresentando aspecto morfológico distinto, com um espículo lateral recurvado. / Abstract: In the schistosomiasis mansoni, the granulomatous reaction that happens around the S. mansoni eggs constitutes the principal pathogenic manifestation. The granulomatous answer showed to be specific for the eggs to each one of the three main of Schistosoma species that parasite the man (S. mansoni, S. haematobium and S. japonicum). The granulomatous reaction that grows around the S. mansoni eggs is specific stage. The objectives of this work were to study the evolution of the granulomatous reactions around the S. mansoni eggs of the BH and SJ strain, to check if the granulomatous reaction around the S. mansoni egg is specific strain and to evaluate the S. mansoni pathogenesis, of the isolated strain from Jardim São Domingos (Campinas, SP), carrying out a comparative study with the BH and SJ strains. To the study of the evolution of the granulomatous reactions, two groups of mice were inoculated by the vein tail with ripe eggs of the BH and SJ strain and sacrificed after 1, 8, 15 and 34 days. To the specific study of the granulomatous reaction, two groups of mice were infected by S. mansoni cercariae BH and in the 8th week of infection, a group was inoculated by the vein tail with BH eggs and other group with SJ eggs. The mice were killed after 1, 8, 15 and 34 days after the eggs inoculation. The analyzed parameters were: number of granulomas for area of lung tissue and hepatic and size of the granulomatous reactions. To evaluate the S. mansoni pathogenesis of the isolated strain in the Jardim São Domingos (Campinas, SP) and to accomplish a comparative study with the strains BH and SJ, three groups of infected mice were constituted and in the eighth week of infection, the surviving mice were sacrificed for recovery of the worms. The verified parameters were: number of penetrating cercariae; number of eliminated eggs in the feces; schistosome number in the system portal-mesenteric; number of granulomas present in the liver, spleen, intestine (ascending colon), pancreas and lung, area of the granulomas observed in the liver and intestine and the S. mansoni eggs size. The conclusions allowed that the granulomatous reaction around the S. mansoni eggs from BH and SJ strains, showed to be specific strain, indicating there to be partial identity in the answer granulomatous among the eggs of the two strains. The informations obtained in the study of the SD strain of S. mansoni indicated to be this strain, the most pathogenic of the strains described already, that has B. tenagophila as trematode host. In the mice infected with this strain was observed a greatest recuperation of worms (48,62%) in relation to the number of cercariae penetrating ( = 64,50), a greatest number of granulomas in most of the innards a greatest granulomatous reaction around the trematode eggs and a greatest size of the eggs (155,60 µm x 64,63 µm). About epidemic importance, it was the established high number of eliminated eggs in the feces, presenting morphological different aspect, with a side recurved spine. / Doutorado / Doutor em Parasitologia

Orientador: Luiz Augusto Magalhães / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T14:43:10Z (GMT). No. of bitstreams: 1 Oliveira_DanteFerreirade_M.pdf: 4679239 bytes, checksum: 8289c39d5ca804477229fe8194c1d9c1 (MD5) Previous issue date: 2013 / Resumo: Estima-se que a esquistossomose, infecte cerca de 200 milhões de pessoas em 75 países em desenvolvimento no mundo. A larga dispersão dos moluscos transmissores e a relevância da migração interna como fator de instalação da esquistossomose mansônica tem sido um importante fator para se delinear estratégias de prevenção e controle. Do ponto de vista epidemiológico, é importante conhecer quais são as espécies de planorbídeos presentes em determinada região e seu potencial para instalação da doença. O objetivo desse estudo foi avaliar o panorama de distribuição de criadouros de moluscos planorbídeos no município de Monte Mor, SP, através de um levantamento malacológico em coleções de água doce, sua positividade para o Schistosoma mansoni, testar a suscetibilidade dos moluscos encontrados frente a linhagens distintas do trematódeo e como pesquisa complementar análise de fezes de indivíduos oriundos de áreas endêmicas de todo o país, que trabalham na agricultura local. O estudo de campo foi realizado com coletas de mosluscos pelo período de 4 meses em coleções de água doce, através de coletas exaustivas em coleções acessíveis. O material coletado foi analisado e identificado no Laboratório de Helmintologia da Unicamp. Através deste estudo foi possível concluir que existe uma vasta distribuição de moluscos no município de Monte Mor composta pelas espécies: Biomphalaria tenagophila, B. straminea, B. intermedia, B. occidentalis, B. peregrina; além de exemplares dos gêneros: Physa, Lymnaea, Melanoides, Drepanotrema, Pomacea e Achatina. Entre os exemplares coletados de moluscos todos se apresentaram negativos ao S. mansoni e outras larvas de trematódeos. Descendentes dos moluscos planorbídeos do gênero Biomphalaria coletados foram submetidos à exposição individual por 10 miracídios de Schistosoma mansoni das cepas BH, SJ, Pernambuco, Sergipe e Bahia. Neste experimento, espécies de B. tenagophila e B. straminea se infectaram com S. mansoni de Pernambuco. Outras espécies de moluscos se mostraram negativas para a infecção pelo Schistosoma mansoni. As análises complementares de fezes dos trabalhadores locais não apresentaram resultados parasitológicos positivos, o que não descarta sua relevância na transmissão da doença frente ao fluxo anual de diferentes trabalhadores para o trabalho na agricultura local / Abstract: It is estimated that schistosomiasis, infects about 200 million people in 75 countries in the developing world. The wide dispersal of snails transmitters and relevance of internal migration as a factor installation schistosomiasis has been an important factor in order to outline strategies for prevention and control. From the epidemiological point of view, it is important to know what are the snails species present in a given region and its potential for desease onset. The aim of this study was to find a picture of the situation of the distribution of breeding of freshwater snails in the municipality of Monte Mor, SP, throughout a malacological in collections of freshwater, its positivity Schistosoma mansoni, test the susceptibility clam found against distinct strains of S. mansoni and how complementary research scat analysis of individuals from endemic areas throughout the country, working in local agriculture. The field study was conducted with snails collections for a period of four months in collections of freshwater through exhaustive collections of collections accessible. The collected material was analyzed and identified in the laboratory of Helminthology UNICAMP. Through this study it was concluded that there is a wide distribution of snails in the municipality of Monte Mor composed by species: Biomphalaria tenagophila, B. straminea, B. intermedia, B. peregrina e B. occidentalis, besides copies of genres: Physa, Lymnaea, Melanoides, Drepanotrema, Pomacea e Achatina. Among the species collected shellfish all were negative to S. mansoni and other trematode larvae. Descendants of freshwater snails of the genus Biomphalaria collected underwent solo exhibition by 10 miracidia of S. mansoni strains Belo Horizonte, São José dos Campos, Pernambuco, Sergipe e Bahia, where they were checked positivity rates of 13.33% from the line of Pernambuco for species B. tenagophila and 3.33% strain Pernambuco for the species B. straminea. Other species of snails were negative for infection with S. mansoni. The complementary analyzes of feces of local workers did not show positive results parasitological, which does not rule out its relevance in disease transmition across the annual flow of different workers to work in local agriculture / Mestrado / Parasitologia / Mestre em Parasitologia