Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-06-29T13:52:59Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) tese_final.pdf: 5635071 bytes, checksum: b300efb627e9ece412ad5936ab67e8e2 (MD5) / Made available in DSpace on 2016-06-29T13:52:59Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) tese_final.pdf: 5635071 bytes, checksum: b300efb627e9ece412ad5936ab67e8e2 (MD5) Previous issue date: 2013-08-26 / CNPq / No presente trabalho duas classes de problemas são abordadas. Primeiramente, são apresentados estudos computacionais sobre o modelo O(n) de spins na rede quadrada, e em seguida apresentamos novas soluções exatas para a dinâmica de bolhas na célula de Hele-Shaw. O estudo do modelo O(n) é feito utilizando sua representação em laços (cadeias fechadas), a qual é obtida a partir de uma expansão para altas temperaturas. Nesse representação, a função de partição do modelo possui uma expansão diagramática em que cada termo depende do número e comprimento total de laços e do número de (auto)interseções entre esses laços. Propriedades críticas do modelo de laços O(n) são obtidas através de conceitos oriundos da teoria de percolação. Para executar as simulações Monte Carlo, usamos o eficiente algoritmo WORM, o qual realiza atualizações locais através do movimento da extremidade de uma cadeia aberta denominada de verme e não sofre com o problema de "critical slowing down". Para implementar esse algoritmo de forma eficiente para o modelo O(n) na rede quadrada, fazemos uso de um nova estrutura de dados conhecida como listas satélites. Apresentamos estimativas para o ponto crítico do modelo para vários valores de n no intervalo de 0 < n ≤ 2. Usamos as estatísticas de laços e vermes para extrair, respectivamente, os expoentes críticos térmicos e magnéticos do modelo. No estudo de dinâmica de interfaces, apresentamos uma solução exata bastante geral para um arranjo periódico de bolhas movendo-se com velocidade constante ao longo de uma célula de Hele-Shaw. Usando a periodicidade da solução, o domínio relevante do problema pode ser reduzido a uma célula unitária que contém uma única bolha. Nenhuma imposição de simetria sobre forma da bolha é feita, de modo que a solução é capaz de produzir bolhas completamente assimétricas. Nossa solução é obtida por métodos de transformações conformes entre domínios duplamente conexos, onde utilizamos a transformação de Schwarz-Christoffel generalizada para essa classe de domínios. / In this thesis two classes of problems are discussed. First, we present computational studies of the O(n) spin model on the square lattice and determine its critical properties, whereas in the second part of the thesis we present new exact solutions for bubble dynamics in a Hele-Shaw cell. The O(n) model is investigated by using its loop representation which is obtained from a high-temperature expansion of the original model. In this representation, the partition function admits an diagrammatic expansion in which each term depends on the number and total length of loops (closed graphs) as well as on the number of intersections between these loops. Critical properties of the O(n) model are obtained by employing concepts from percolation theory. To perform Monte Carlo simulations of the model, we use the WORM algorithm, which is an efficient algorithm that performs local updates through the motion of one of the ends (called head) of an open chain (called worm) and hence does not suffer from “critical slowing down”. To implement this algorithm efficiently for the O(n) model on the square lattice, we make use of a new data structure known as a satellite list. We present estimates for the critical point of the model for various values of n in the range 0 < n ≤ 2. We use the statistics about the loops and the worm to extract the thermal and magnetic critical exponents of the model, respectively. In our study about interface dynamics, we present a rather general exact solution for a periodic array of bubbles moving with constant velocity in a Hele-Shaw cell. Using the periodicity of the solution, the relevant domain of the problem can be reduced to a unit cell containing a single bubble. No symmetry requirement is imposed on the bubble shape, so that the solution is capable of generating completely asymmetrical bubbles. Our solution is obtained by using conformal mappings between doubly-connected domains and employing the generalized Schwarz-Christoffel formula for this class of domains.

Schneckenradgetriebe sind aufgrund ihrer Verzahnungsgeometrie prädestiniert für Getriebeanwendungen mit diskontinuierlichem und schwingungsbehaftetem Betrieb. Bei hohen Momenten und geringen Drehzahlen stellt dabei die Zahnfußtragfähigkeit die primäre Auslegungsgrenze dar. Das Ziel der vorliegenden Arbeit lag in der Erhöhung der Genauigkeit der Berechnungsmethoden für die Zahnfußtragfähigkeit von Schneckenrädern, auch zur Steigerung des Volumennutzwertes dieser Getriebe. Hierzu wurden alle die Tragfähigkeit des Zahnfußes beeinflussenden Parameter durch eine Vielzahl von Experimenten und FE Simulationen untersucht. Dies schließt eine genaue Analyse der Geometrie von Schneckengetrieben, deren Fertigung und Einbausituation, die verwendeten Werkstoffe und deren Beanspruchung mit ein. Auf dieser Basis gelang neben der Entwicklung eines vergleichsspannungsbasierten analytischen Berechnungsverfahrens die Erstellung eines örtlichen Berechnungskonzeptes nach dem Kerbspannungskonzept. Hiermit konnte die Einschätzung der Zahnfußtragfähigkeit bei der Neuentwicklung und die Optimierung von Getrieben verbessert werden. / Worm gears are well suited for gearbox applications in environments with discontinuous conditions and mechanical vibrations. In the case of high torque and low speed, the tooth root strength is the primary design limit. The aim of the present paper is to improve the accuracy of the calculation methods for the tooth root strength of worm wheels. To reach this, all parameters which affects the strength of the tooth root were examined. This includes the geometry, the manufacturing, the materials and the stresses of worm wheels. Through this investigation, the development of a new analytical calculation method based on the equivalent stress concept could be done. Furthermore, a local calculation method based on the notch stress concept was developed. Thus, the forecast of the tooth root strength of worm wheels for redevelopment and optimization could be improved.

The quantum phase transition between groundstates of a system with correlated disorder near absolute zero is studied. The computations are based on Monte Carlo methods and the worm algorithm which is an effective method to simulate basic models like the Ising and XY model by making use of global Monte Carlo moves given by modified random walks. Random quenched disorder modeled as a correlated distribution of two values of the coupling constant gives rise to an additional phase transition with a not before seen intermediate phase. / Kvantfasövergången mellan grundtillstånd av ett system med korrelerad oordning nära nolltemperaturen studeras. Beräkningarna är baserade på Monte Carlo metoder och worm algoritmen som är en effektiv metod för att simulera grundläggande modeller som Ising och XY modellen genom att använda sig av globala Monte Carlo steg som ges av modifierade slumpmässiga vandringar. Slumpmässig infrusen oordning modellerad som en korrelerad fördelning av två värden på kopplingsstyrkan ger upphov till en ny mellanliggande fas.

Introduction: Guinea worm disease (GWD) is a painful, disabling disease caused by the parasite dracunculus medinensis. The implementation of the global GWD eradication campaign resulted in a decrease of global burden of disease and several countries have been proclaimed free of the disease. Though, Ethiopia has implemented the GWD eradication programme since 1992 the disease remains endemic in the Gambella region. Purpose of the study: The purpose of this study was to explore the perceptions and experiences of the community of Gambella region on Guinea worm disease (GWD) eradication interventions. Methodology: A qualitative study paradigm with a phenomenological research design was employed to collect data using focus group discussions, in-depth individual interviews, document reviews, and observations. The study participants were determined by purposive sampling. Qualitative data analysis involved transcription, data entry, and management of verbal information followed by coding, categorizing into themes. Interpretation of the data was done using triangulation methodology with appropriate mechanisms for validity and trustworthiness. Result: The study found that there are gaps in the perceptions and understanding of the community and programme implementers about the achievement and application of the various interventions on the eradication of Guinea worm disease. Health education programme was not fine-tuned to the eradication of GWD by community participation. Community perception was not at the required level for the eradication of GWD due to the low success of the educational intervention. Conclusion: continuous health education targeting the community with clear objectives of helping to eradicate GWD was found to be limited in its coverage. In addition, provision of water filters necessary for GWD eradication was inadequate. Moreover, the community did not have clear understanding of the causes of GWD and its eradication strategy. It is hoped that the findings of this study would contribute significantly to the GWEP in Gambella region, as well as elsewhere where GWD may be endemic / Health Studies / M.A. (Public Health)

The ability to accurately identify species is fundamental to ecological research and environmental monitoring. Current taxonomic identifications often rely on differentiation of morphologically ambiguous characters, and a process of categorization which is tedious and often leads to misidentifications. This is compounded by the presence of cryptic taxa, which may be prevalent among Polychaete worms (Polychaeta: Annelida). With increased access to genetic techniques, Cytochrome c oxidase subunit I has been suggested as a possible aid to assist in the discrimination of species resources. In this study, I tested the hypothesis that the mtDNA COI gene locus is effective in discriminating morphologically recognised species of Polychaete worms. A 543 base-pair fragment of the COI locus was successfully extracted for 111 individuals from 16 out of 20 morphologically recognised species. Average intraspecific divergences were 0.8 %, ranging from 0 % to 5 %. Average interspecific variation was 26.4 %, ranging from 13.8 % to 36.8 %. The lowest divergences were found between two Nereid species (13.8 %), and two Glycera americana species (17.2 %). Relatively high maximum divergences of over 30 % suggest that some species may have reached a divergence saturation level, which may partially explain why familial groupings in constructed trees were not monophyletic. Divergences within the different Nereid species - a group previously known to have morphologically cryptic species - did not reveal the presence of any cryptic taxa. Pairwise comparisons showed a clear divide between percentages of intra- and interspecific divergences, and the suggested threshold of 11 % is effective for the taxa investigated here. On the basis of these results, I conclude that sequence variation in the mtDNA COI gene locus is effective in discriminating morphologically recognised species of Polychaete worms, but may not be appropriate for deeper (e.g. generic or familial) phylogenetic relationships among taxa.

Master of Veterinary Clinical Studies / Summary Canine Neural Angiostrongyliasis (CNA) is caused by the obligatory neural migration of Angiostrongylus cantonensis larvae in dogs. Characteristically, cases are juvenile dogs with progressive CNS dysfunction characterised by hyperaesthesia and often associated with eosinophilic pleocytosis of the CSF. In Australia, most cases occur between March and June. The rat lungworm, A cantonensis was first described by Chen in 1935 in Canton, China. While initially called Pulmonema cantonensis the parasite was later reclassified as A cantonensis. A disease diagnosed as eosinophilic meningoencephalitis was first described in 1944 in Taiwan. The same disease was reported in 1948 in the East Caroline Islands but it was not until 1961 that A cantonensis was confirmed as the aetiological agent when a patient in a Hawaiian mental institution, who had died of eosinophilic meningoencephalitis, had A cantonensis larvae recovered from the brain and spinal cord. The first reports of animals infected with A cantonensis were made by Mason in 1976 when he described a syndrome occurring in puppies in the Brisbane area, characterised by urinary incontinence, hind limb paresis and hyperaesthesia, often associated with eosinophilic pleocytosis of the CSF. Reports of infection in other species followed including macropods, bats, horses, primates and birds. Twenty-two cases of suspected CNA were collected prospectively to compare with those previously described, including 37 cases published by Mason in 1983, and to examine the accuracy of an ELISA used to diagnose human neural angiostrongyliasis in Australia. Samples were collected from two control populations in an attempt to validate the ELISA results. In the prospective series of cases, there was a significantly older subpopulation of dogs in addition to “classical” young dogs, suggesting that this syndrome can occur at any age and should be considered a differential in any dog with progressive neurological disease. The mortality rate in the prospective group was lower than in the published group, which is a reflection of the severity of the disease in younger animals as is the case with human patients. Definitive diagnosis of neural angiostrongyliasis in human patients has been achieved by identifying A cantonensis larvae within the CSF or aqueous humour. In dogs, the only definitive way to diagnose CNA has been via necropsy. While many cases of CNA are characteristic and presumptive diagnosis can be made based on typical history, signalment, clinical signs, CSF analysis and response to glucocorticoids, there appear to be an increasing number of cases occurring in older dogs, that displaying focal, atypical clinical signs or that develop permanent sequelae. Serology has been a useful tool in diagnosing neural angiostrongyliasis in humans. In its current form the ELISA is not sensitive or specific enough to allow a definitive diagnosis of CNA to be made using serum but is useful when applied to CSF specimens. Further refinement of the antigen or using monoclonal rather than polyclonal antibodies may improve the accuracy of the serology. Alternatively, methods such as Western Blot, Immuno-PCR or dot-blot ELISA, which have been successfully used to diagnoses angiostrongyliasis in humans, may be worthy of investigation The major differential diagnosis for CNA is neosporosis. Other differential diagnoses include idiopathic eosinophilic meningoencephalitis, parasitic infections including Toxoplasma gondii, Taenia solium, Gnathostoma spinigerum, visceral larval migrans (Toxocara canis) and schistosomiasis, fungal, bacterial, viral and rickettsial infections as well as neoplasia, trauma, drug reactions and toxicities. Treatment of CNA has been limited to glucocorticoids, however there may be adjunct therapies including anthelmintices, cyclosporine, and matrix metalloproteinase inhibitors. In Mason’s series of cases the use of anthelmintics significantly worsened the clinical outcome for patients. It does not appear, however, that the use of these agents in species other than the dog exacerbates clinical signs. Acquired immunity is short lived in rats and mice, which would suggest the same is true in dogs. Routine heartworm and intestinal parasite prophylaxis appears to have no influence on the occurrence of CNA.

Src homology 3 (SH3) domains are one family of the peptide recognition modules (PRMs), which bind peptides rich in proline or positively charged residues in the target proteins, and play important assembly or regulatory functions in dynamic eukaryotic cellular processes, especially in signal transduction and endocytosis. SH3 domains are conserved from yeast to human, and improper SH3 domain mediated protein-protein interaction (PPI) leads to defects in cellular function and may even result in disease states. Since commonly used large-scale PPI mapping strategies employed full-length proteins or random protein fragments as screening probes and did not identify the particular PPIs mediated by the SH3 domains, I employed a combined experimental and computational strategy to address this problem. I used yeast two-hybrid (Y2H) as my major experimental tool, as well as individual SH3 domains as baits, to map SH3 domain mediated PPI networks, “SH3 domain interactomes”. One of my important contributions has been the improvement for Y2H technology. First, I generated a pair of Y2H host strains that improved the efficiency of high-throughput Y2H screening and validated their usage. These strains were employed in my own research and also were adopted by other researchers in their large-scale PPI network mapping projects. Second, in collaboration with Nicolas Thierry-Mieg, I developed a novel smart-pooling method, Shifted Transversal Design (STD) pooling, and validated its application in large-scale Y2H. STD pooling was proven to be superior among currently available methods for obtaining large-scale PPI maps with higher coverage, high sensitivity and high specificity. I mapped the SH3 domain interactomes for both budding yeast Saccharomyces cerevisiae and nematode worm Caenorhabditis elegans, which contain 27 and 84 SH3 domains, respectively. Comparison of these two SH3 interactomes revealed that the role of the SH3 domain is conserved at a functional but not a structural level, playing a major role in the assembly of an endocytosis network from yeast to worm. Moreover, the worm SH3 domains are additionally involved in metazoan-specific functions such as neurogenesis and vulval development. These results provide valuable insights for our understanding of two important evolutionary processes from single cellular eukaryotes to animals: the functional expansion of the SH3 domains into new cellular modules, as well as the conservation and evolution of some cellular modules at the molecular level, particularly the endocytosis module.

Src homology 3 (SH3) domains are one family of the peptide recognition modules (PRMs), which bind peptides rich in proline or positively charged residues in the target proteins, and play important assembly or regulatory functions in dynamic eukaryotic cellular processes, especially in signal transduction and endocytosis. SH3 domains are conserved from yeast to human, and improper SH3 domain mediated protein-protein interaction (PPI) leads to defects in cellular function and may even result in disease states. Since commonly used large-scale PPI mapping strategies employed full-length proteins or random protein fragments as screening probes and did not identify the particular PPIs mediated by the SH3 domains, I employed a combined experimental and computational strategy to address this problem. I used yeast two-hybrid (Y2H) as my major experimental tool, as well as individual SH3 domains as baits, to map SH3 domain mediated PPI networks, “SH3 domain interactomes”. One of my important contributions has been the improvement for Y2H technology. First, I generated a pair of Y2H host strains that improved the efficiency of high-throughput Y2H screening and validated their usage. These strains were employed in my own research and also were adopted by other researchers in their large-scale PPI network mapping projects. Second, in collaboration with Nicolas Thierry-Mieg, I developed a novel smart-pooling method, Shifted Transversal Design (STD) pooling, and validated its application in large-scale Y2H. STD pooling was proven to be superior among currently available methods for obtaining large-scale PPI maps with higher coverage, high sensitivity and high specificity. I mapped the SH3 domain interactomes for both budding yeast Saccharomyces cerevisiae and nematode worm Caenorhabditis elegans, which contain 27 and 84 SH3 domains, respectively. Comparison of these two SH3 interactomes revealed that the role of the SH3 domain is conserved at a functional but not a structural level, playing a major role in the assembly of an endocytosis network from yeast to worm. Moreover, the worm SH3 domains are additionally involved in metazoan-specific functions such as neurogenesis and vulval development. These results provide valuable insights for our understanding of two important evolutionary processes from single cellular eukaryotes to animals: the functional expansion of the SH3 domains into new cellular modules, as well as the conservation and evolution of some cellular modules at the molecular level, particularly the endocytosis module.

Nous avons établi, dans la base des descriptions des menaces informatiques Threat Explorer de Symantec un groupe de descriptions répertoriées virus et nous avons essayé de les traduire en lituanien en nous servant des sources terminographiques qui sont à disposition en lituanien et qui datent de 1971 à 2012. Très vite, nous nous sommes rendus compte qu’un groupe assez important de termes anglais et français désignant différents types de virus informatiques n’avaient pas d’équivalents lituaniens. De même, nous avons observé que, pendant une trentaine d’années de son existence, le concept de virus informatique a toujours été confondu avec d’autres concepts de même niveau tels que ver informatique, ou tout court ver, et cheval de Troie. Ces confusions ont engendré un échec de traduction des descriptions mentionnées précédemment et nous ont ammené vers l’idée de rédiger un travail, la présente thèse, afin d’identifier les raisons de l’impossibilité de nous fier aux sources terminologiques lituaniennes, de les analyser pour ensuite proposer des solutions fondées sur les conclusions d’une étude scientifique. / Sąvoka kompiuterių virusas gyvuoja nuo 1984 m., tačiau net ir praėjus trims dešimtmečiams lietuvių kalboje ji vis dar nėra pakankamai diferencijuota, tebėra painiojama su kitomis kompiuterių saugumui priskiriamomis sąvokomis, dažniausiai kirminu ir Trojos arkliu. Iki šiol nebuvo atlikta išsamių lingvistinių nagrinėjamos sąvokos ir jos žymiklio tyrimų lietuvių kalba. Šios disertacijos tikslas – aprašyti sąvokos kompiuterių virusas semantinį lauką, kurio pagrindas yra termino kompiuterių virusas mikrosistema. Tirta 919 Symantec kompiuterių grėsmių banke Threat Explorer paskelbtų kompiuterių grėsmių aprašų su žyma Virus, Threat Explorer partnerių terminografiniai ištekliai ir Lietuvoje nuo 1984 m. iki 2006 m. išleisti kompiuterijos terminų žodynai bei tuo pačiu laikotarpiu paskelbti analitiniai straipsniai apie kompiuterijos leksiką Lietuvos mokslo leidiniuose. Sąvokos raidai įvertinti įtraukta papildomų terminografinių išteklių lietuvių ir prancūzų kalbomis. Visi surinkti terminologiniai duomenys apie nagrinėjamos sąvokos semantinį lauką, kurį šiame darbe sudaro 177 sąvokos, tirti taikant šiuos metodus: lyginamąjį, aprašomąjį, komponentinės analizės ir aukštynkryptės analizės metodais. Tyrimo metu paaiškėjo, kad disertacijoje nagrinėjamos sąvokos semantinį lauką dėl jį sudarančių sąvokų tarpusavio hierarchinių santykių galima gana tiksliai apibrėžti. Toks semantinių laukų teorijos taikymas terminologiniams duomenims, iš kurių svarbiausiu laikoma intensinė termino apibrėžtis... [toliau žr. visą tekstą] / The concept “computer virus” has been in existence since 1984. However despite the fact that almost 30 years have passed, it is not properly defined in Lithuanian sources and is still confused with other concepts tied to computer security, most often with concepts such as “worms” and “Trojan horses.” There has never been comprehensive linguistic research carried out on this concept and its signifier in Lithuanian. The aim of this dissertation is to describe the semantic field of the concept “computer virus,” the basis of which is the microsystem of the term “computer virus.” The following was used for the research: a total of 919 computer threat descriptions included in the Symantec computer threat bank that are tagged virus, the terminographical resources of Threat Explorer partners and computer terminology dictionaries published in Lithuania from 1984 to 2006 as well as analytical articles about computer terminology in Lithuanian scientific journals during the same period. Additional terminographical resources in Lithuanian and French are included in the research to assess and analyze the development of this concept. All of the terminological date that was collected concerning the semantic field of the concept in question (comprised of 177 concepts in this work) was analysed using the following methods: the comparative method, descriptive method, componential analysis and uplink analysis. As the research was carried out, it became clear that the semantic field of the... [to full text]

Master of Veterinary Clinical Studies / Summary Canine Neural Angiostrongyliasis (CNA) is caused by the obligatory neural migration of Angiostrongylus cantonensis larvae in dogs. Characteristically, cases are juvenile dogs with progressive CNS dysfunction characterised by hyperaesthesia and often associated with eosinophilic pleocytosis of the CSF. In Australia, most cases occur between March and June. The rat lungworm, A cantonensis was first described by Chen in 1935 in Canton, China. While initially called Pulmonema cantonensis the parasite was later reclassified as A cantonensis. A disease diagnosed as eosinophilic meningoencephalitis was first described in 1944 in Taiwan. The same disease was reported in 1948 in the East Caroline Islands but it was not until 1961 that A cantonensis was confirmed as the aetiological agent when a patient in a Hawaiian mental institution, who had died of eosinophilic meningoencephalitis, had A cantonensis larvae recovered from the brain and spinal cord. The first reports of animals infected with A cantonensis were made by Mason in 1976 when he described a syndrome occurring in puppies in the Brisbane area, characterised by urinary incontinence, hind limb paresis and hyperaesthesia, often associated with eosinophilic pleocytosis of the CSF. Reports of infection in other species followed including macropods, bats, horses, primates and birds. Twenty-two cases of suspected CNA were collected prospectively to compare with those previously described, including 37 cases published by Mason in 1983, and to examine the accuracy of an ELISA used to diagnose human neural angiostrongyliasis in Australia. Samples were collected from two control populations in an attempt to validate the ELISA results. In the prospective series of cases, there was a significantly older subpopulation of dogs in addition to “classical” young dogs, suggesting that this syndrome can occur at any age and should be considered a differential in any dog with progressive neurological disease. The mortality rate in the prospective group was lower than in the published group, which is a reflection of the severity of the disease in younger animals as is the case with human patients. Definitive diagnosis of neural angiostrongyliasis in human patients has been achieved by identifying A cantonensis larvae within the CSF or aqueous humour. In dogs, the only definitive way to diagnose CNA has been via necropsy. While many cases of CNA are characteristic and presumptive diagnosis can be made based on typical history, signalment, clinical signs, CSF analysis and response to glucocorticoids, there appear to be an increasing number of cases occurring in older dogs, that displaying focal, atypical clinical signs or that develop permanent sequelae. Serology has been a useful tool in diagnosing neural angiostrongyliasis in humans. In its current form the ELISA is not sensitive or specific enough to allow a definitive diagnosis of CNA to be made using serum but is useful when applied to CSF specimens. Further refinement of the antigen or using monoclonal rather than polyclonal antibodies may improve the accuracy of the serology. Alternatively, methods such as Western Blot, Immuno-PCR or dot-blot ELISA, which have been successfully used to diagnoses angiostrongyliasis in humans, may be worthy of investigation The major differential diagnosis for CNA is neosporosis. Other differential diagnoses include idiopathic eosinophilic meningoencephalitis, parasitic infections including Toxoplasma gondii, Taenia solium, Gnathostoma spinigerum, visceral larval migrans (Toxocara canis) and schistosomiasis, fungal, bacterial, viral and rickettsial infections as well as neoplasia, trauma, drug reactions and toxicities. Treatment of CNA has been limited to glucocorticoids, however there may be adjunct therapies including anthelmintices, cyclosporine, and matrix metalloproteinase inhibitors. In Mason’s series of cases the use of anthelmintics significantly worsened the clinical outcome for patients. It does not appear, however, that the use of these agents in species other than the dog exacerbates clinical signs. Acquired immunity is short lived in rats and mice, which would suggest the same is true in dogs. Routine heartworm and intestinal parasite prophylaxis appears to have no influence on the occurrence of CNA.