Since the establishment of West Nile virus (WNV) in North America, concern has arisen that this virus may also pose a biosecurity threat to Australia. West Nile virus is maintained in an enzootic transmission cycle between birds and ornithophilic Culex spp. mosquitoes. Since its introduction into the United States in 1999, it has been responsible for over 11,000 human cases of neurological disease and over 1,000 human deaths. In addition, WNV has caused extensive equine and avian mortality. Should an exotic, virulent strain of WNV be introduced into Australia, it may have significant impact on human and animal health. This thesis examines entomological factors which may influence the potential for an exotic, pathogenic strain of WNV to become established in eastern Australia and be maintained in urban transmission cycles. Further, it aims to elucidate the most likely candidate vectors for the maintenance of WNV in natural transmission cycles. Components include: a) laboratory-based vector competence experiments to assess the ability of Australian mosquito species to become infected with and transmit a North American strain of WNV; b) identification of the vertebrate origin of mosquito bloodmeals using serological and molecular assays; c) an evaluation of the efficacy of bird-baited traps for collecting ornithophilic mosquitoes at ground level and in the tree canopy; and d) examination of the prevalence of endemic arboviruses, including Kunjin virus (KUNV; an Australian subtype of WNV) in mosquitoes collected from urban centres of eastern Australia. Vector competence experiments were conducted with field-collected Australian mosquito species. Nineteen species were were exposed to a 1999 New York strain of WNV using an artificial membrane feeding apparatus and transmission was attempted using an in vitro modified capillary tube method. A number of Culex species, including Culex quinquefasciatus and Culex gelidus, demonstrated high vector competence for WNV. Culex annulirostris, the primary KUNV vector, was the most competent vector, displaying transmission rates of 84%. Other common species, including Aedes vigilax, Aedes procax and Verrallina spp. were less susceptible to infection. Approximately 1,200 blood engorged mosquitoes were analysed using an enzyme-linked immunosorbent assay to determine host species. Overall, 90% of bloodmeals from Cx. quinquefasciatus were avian in origin, while 22% of bloodmeals from Cx. annulirostris were from birds. Molecular assays were further used to determine which bird species were commonly targeted by a selection of ornithophilic mosquito species. Mitochondrial DNA sequence data indicated that most (93%) avian bloodmeals from Cx. quinquefasciatus were obtained from passerine birds (order Passeriformes). Avian species commonly targeted by Cx. quinquefasciatus included Sphecotheres vieilloti (Australasian figbird; 39% of total identified), Sturnus tristis (common myna; 19%) and Philemon buceroides (helmeted friarbird; 17%). Alternatively, the majority (87%) of avian bloodmeals identified from Cx. annulirostris were from non-passerine birds, with most bloodmeals obtained from ducks (72%; family Anatidae). Seven field-based Latin Square trials conducted in Brisbane and Cairns showed that conventional CO2-baited CDC traps yielded higher numbers of Culex spp. than novel bird-baited traps, both at ground level and in the tree canopy. In Brisbane, CO2-baited CDC traps placed at ground level (approximately 1 m from ground) collected significantly more Cx. annulirostris than those at canopy height (5-10 m) during two trials, and more Ae. vigilax and Aedes procax during one trial each. Conversely, in Cairns, CO2-baited CDC traps placed in the tree canopy collected significantly more Culex squamosus during two trials, and significantly more Aedeomyia catasticta and Culex cubiculi during one trial each. Consistently low yields of ornithophilic species including Culex australicus and Cx. quinquefasciatus in all traps tested suggests the need to employ alternative trapping measures to target these species in urban areas. Over 1,800 mosquito pools (comprising over 65,000 individual mosquitoes collected from urban environments) were tested for evidence of arboviral infection. None of the pools showed evidence of flavivirus infection, but two alphaviruses were isolated from mosquito pools from Cairns. One isolate of Barmah Forest virus was obtained from a pool of 100 Ae. vigilax, and a pool of 89 Verrallina carmenti yielded an isolate of Ross River virus. In addition, an isolate most similar to a newly described bunyavirus, Stretch Lagoon orbivirus, was obtained from a single Aedes alternans collected from Sydney. The outcomes of this thesis demonstrate that a number of Australian mosquito species can become infected with and transmit a virulent strain of WNV, should it be introduced into Australia. Analysis of the host feeding patterns of these potential vectors in urban environments demonstrates that a number of candidate vectors, including Cx. quinquefasciatus and Cx. annulirostris, readily feed on common bird species. Further, the absence of detectable flavivirus infection in urban mosquito populations shown here suggests that endemic urban flaviviruses would have minimal influence on potential WNV transmission. Notwithstanding other ecological factors that may influence the likelihood of enzootic or epizootic transmission including susceptibility of vertebrate hosts and mechanisms of introduction, the potential establishment of an exotic, virulent strain of WNV in urban areas of Australia is certainly possible given the evidence provided in this thesis.

Biomarkers are biological measures used for clinical assessment, whether an individual has a particular medical condition or to monitor and predict health states in individuals. Sensitive detection and quantification of various biomarkers are essential for disease diagnostics. The majority of biomarker-based diagnostics examines the presence and quantity of a single biomarker. Since the symptoms of many diseases are alike, multiplexed biomarker tests are highly desirable. Furthermore, detection of multiple biomarkers would improve the accuracy of diagnosis as well as providing additional information about the prognosis. Microarray platforms have the potential for higher level of multiplexing for biomarker detection. However, conventional microarray technologies are limited by the sensitivity of assays. This dissertation describes how single-particle interferometric reflectance imaging sensor (SP-IRIS) overcomes the sensitivity issues in biomarker detection and its applications to biomolecular and cellular biomarker detection assays. SP-IRIS provides optical detection of individual nanoparticles when they are captured onto a simple reflecting substrate, providing single-molecule sensitivity. This technique can be used to detect natural nanoparticles (such as viruses) without labels as well as molecular analytes (proteins and nucleic acids) that are labeled with metallic nanoparticles. Moreover, the advancements in technology make SP-IRIS ideal for the detection of low abundance biomarkers. Utilization of light polarization in combination with plasmonic gold nanorods as labels enhances the signal-to-noise ratio in nanoparticle detection allowing for the use of low numerical aperture optics increasing the field-of-view, hence, the throughput and sensitivity. Additionally, the integration of a disposable microfluidic flow cell and dynamic particle tracking in kinetic measurements provide a robust, ultra-sensitive and automated diagnostic platform. This dissertation focuses on the development of biological assays demonstrating effective use of SP-IRIS as a clinical diagnostic platform. We discuss the development of protein, nucleic acid and biological nanoparticle detecting SP-IRIS microarrays. We demonstrate four digital detection platforms for Hepatitis B, microRNA, rare mutations in an oncogene, KRAS, and virus-like particle detection with ultra-high sensitivity. / 2022-09-28T00:00:00Z

Biological nanoparticles have enormous utility as well as potential adverse impacts in biotechnology, human health, and medicine. The physical and chemical properties of these nanoparticles have strong implications on their distribution, circulation, and clearance in vivo. Accurate morphological visualization and chemical characterization of nanoparticles by label-free (direct) optical microscopy would provide valuable insights into their natural and intrinsic properties. However, three major challenges related to label-free nanoparticle imaging must be overcome: (i) weak contrast due to exceptionally small size and low-refractive-index difference with the surrounding medium, (ii) inadequate spatial resolution to discern nanoscale features, and (iii) lack of chemical specificity. Advances in common-path interferometric microscopy have successfully overcome the weak contrast limitation and enabled direct detection of low-index biological nanoparticles down to single proteins. However, interferometric light microscopy does not overcome the diffraction limit, and studying the nanoparticle morphology at sub-wavelength spatial resolution remains a significant challenge. Moreover, chemical signature and composition are inaccessible in these interferometric optical measurements. This dissertation explores innovations in common-path interferometric microscopy to provide enhanced spatial resolution and chemical specificity in high-throughput imaging of individual nanoparticles. The dissertation research effort focuses on a particular modality of interferometric imaging, termed “single-particle interferometric reflectance (SPIR) microscopy”, that uses an oxide-coated silicon substrate for enhanced coherent detection of the weakly scattered light. We seek to advance three specific aspects of SPIR microscopy: sensitivity, spatial resolution, and chemical specificity. The first one is to enhance particle visibility via novel optical and computational methods that push optical detection sensitivity. The second one is to improve the lateral resolution beyond the system's classical limit by a new computational imaging method with an engineered illumination function that accesses high-resolution spatial information at the nanoscale. The last one is to extract a distinctive chemical signature by probing the mid-infrared absorption-induced photothermal effect. To realize these goals, we introduce new theoretical models and experimental concepts. This dissertation makes the following four major contributions in the wide-field common-path interferometric microscopy field: (1) formulating vectorial-optics based linear forward model that describes interferometric light scattering near planar interfaces in the quasi-static limit, (2) developing computationally efficient image reconstruction methods from defocus images to detect a single 25 nm dielectric nanoparticle, (3) developing asymmetric illumination based computational microscopy methods to achieve direct morphological visualization of nanoparticles at 150 nm, and (4) developing bond-selective interferometric microscopy to enable multispectral chemical imaging of sub-wavelength nanoparticles in the vibrational fingerprint region. Collectively, through these research projects, we demonstrate significant advancement in the wide-field common-path interferometric microscopy field to achieve high-resolution and accurate visualization and chemical characterization of a broad size range of individual biological nanoparticles with high sensitivity.

No / Yellow leaf syndrome (YLS) of sugarcane has been associated with Sugarcane yellow leaf virus (ScYLV) and has been reported from most sugarcane growing countries around the world. As sugarcane is vegetatively propagated, it is important to use effective and sensitive detection methods to screen new propagating material. Virus detection in symptomatic tissue is currently achieved using enzyme linked immunosorbent assay (ELISA), tissue blot immunoassay (TBIA) or a conventional RT-PCR based assay. This paper reports the development of an improved assay based on multiplex real-time fluorescent RT-PCR. The new assay is 100-fold more sensitive than conventional RT-PCR, and incorporates a novel `RNA specific¿ internal positive control (based around the intron of the caffeic acid 3-o-methyltransferase gene) to guard against false negative results. The paper also describes the comparison of eight RNA extraction methods for sugarcane tissue giving a number of alternatives for different laboratory situations. The sensitivity of this assay has allowed the detection of ScYLV in many samples that were thought to be healthy following conventional testing (RT-PCR, ELISA or TBIA). The detection of ScYLV using this TaqMan assay can be applied to the production of ScYLV-free plants and prevents its spread through the propagation material.

BACKGROUND:In a globalized word, prevention of infectious diseases is a major challenge. Rapid detection of viable virus particles in water and other environmental samples is essential to public health risk assessment, homeland security and environmental protection. Current virus detection methods, especially assessing viral infectivity, are complex and time-consuming, making point-of-care detection a challenge. Faster, more sensitive, highly specific methods are needed to quantify potentially hazardous viral pathogens and to determine if suspected materials contain viable viral particles. Fourier transform infrared (FTIR) spectroscopy combined with cellular-based sensing, may offer a precise way to detect specific viruses. This approach utilizes infrared light to monitor changes in molecular components of cells by tracking changes in absorbance patterns produced following virus infection. In this work poliovirus (PV1) was used to evaluate the utility of FTIR spectroscopy with cell culture for rapid detection of infective virus particles.RESULTS:Buffalo green monkey kidney (BGMK) cells infected with different virus titers were studied at 1 - 12 hours post-infection (h.p.i.). A partial least squares (PLS) regression method was used to analyze and model cellular responses to different infection titers and times post-infection. The model performs best at 8 h.p.i., resulting in an estimated root mean square error of cross validation (RMSECV) of 17 plaque forming units (PFU)/ml when using low titers of infection of 10 and 100 PFU/ml. Higher titers, from 103 to 106 PFU/ml, could also be reliably detected.CONCLUSIONS:This approach to poliovirus detection and quantification using FTIR spectroscopy and cell culture could potentially be extended to compare biochemical cell responses to infection with different viruses. This virus detection method could feasibly be adapted to an automated scheme for use in areas such as water safety monitoring and medical diagnostics.

Os vírus são as entidades biológicas mais abundantes encontradas na natureza. O método clássico de estudo dos vírus requerem seu isolamento e propagação in vitro. Contudo, necessita-se ter um conhecimento prévio sobre as condições necessárias para seu cultivo em células, sendo assim a maior parte dos vírus existentes não é conhecida. Análises metagenômicas são uma alternativa para a detecção e caracterização de novos vírus, uma vez que não requerem um cultivo prévio e as amostras podem conter material genético de múltiplos organismos. Uma vez obtidas as sequências montadas a partir das leituras metagenômicas, o método mais utilizado para a identificação e classificação dos organismos é a busca de similaridade com o programa BLAST contra bancos de sequências conhecidas. Contudo, métodos de alinhamento pareado são capazes de identificar apenas sequências com identidade superior a 20-30%. Uma alternativa a essa limitação é o uso de métodos baseados no uso de perfis, que podem aumentar a sensibilidade de detecção de homólogos filogeneticamente distantes. HMMs de perfil são modelos probabilísticos capazes de representar a diversidade de caracteres em posições-específicas de um alinhamento de múltiplas sequências. Nosso grupo desenvolveu a ferramenta TABAJARA, utilizada neste projeto, para a identificação de blocos que podem ser conservados em todas as sequências do alinhamento ou discriminativos entre grupos de sequências. Esses blocos são utilizados para a geração de HMMs de perfil, os quais podem ser usados, no contexto da virologia, para a identificação de grupos taxonômicos amplos como famílias virais ou, ainda, taxa mais restritos como gêneros ou mesmo espécies de vírus. O presente projeto teve como objetivos aplicar e otimizar o programa TABAJARA em diferentes grupos taxonômicos de vírus, construir modelos específicos para cada um desses grupos e validar esses modelos em dados metagenômicos. O primeiro modelo de estudo escolhido foi a ordem Bunyavirales, composta de vírus de ssRNA (-) majoritariamente envelopados e esféricos, com genoma segmentado e pertencentes ao grupo 5 da classificação de Baltimore. Este grupo inclui vírus causadores de várias doenças em humanos, animais e plantas. O segundo modelo de estudo escolhido foi a família Togaviridae, composta de vírus de ssRNA (+) envelopados e esféricos, cujo genoma expressa uma poliproteína e pertencem ao grupo 4 da classificação de Baltimore. Este grupo inclui o vírus Chikungunya e outras espécies que causam diversas patologias ao homem. O terceiro modelo de estudo escolhido foi a subfamília Spounavirinae, compreendendo bacteriófagos que infectam vários hospedeiros bacterianos e em alguns casos possuem potencial terapêutico comprovado contra infecções bacterianas que afetam o homem. Estes fagos apresentam partículas virais com estrutura cabeça-cauda, não são envelopados, apresentam genoma de dsDNA e pertencem ao grupo 1 da classificação de Baltimore. Todos os modelos construídos foram validados quanto à sensibilidade e especificidade de detecção e, ao final, foram utilizados em análises de prospecção de vírus em dados metagenômicos obtidos na base SRA do NCBI. Os HMMs de perfil apresentaram excelente desempenho, comprovando a viabilidade da metodologia proposta neste projeto. Os resultados apresentados neste trabalho abrem a perspectiva da ampla utilização de HMMs de perfil como ferramentas universais para a detecção e classificação de vírus em dados metagenômicos. / Viruses are the most widely biological entities found in nature. Most of the information that can be obtained from these organisms requires viral in vitro isolation and cultivation. However, most of the existing viruses are still unknown because the biological requirements for their successful propagation have not been identified so far. Metagenomic analyses offer an interesting alternative for the detection and characterization of novel viruses, since previous cultivation is not required, and the samples may contain genetic material of multiple organisms. Once assembled sequences are obtained from individual reads, the most widely used method for viral identification and classification is the use of BLAST similarity searches against databases of known sequences. However, pairwise alignment methods are only able to identify sequences that present identity greater than 20-30%. Profile-based methods may increase the sensitivity of detection of remote homologues. Profile HMMs are probabilistic models capable of representing the diversity of amino acid residues at specific positions of a multiple sequence alignment. Our group is developing TABAJARA, a tool for the identification of alignment blocks that are conserved across all sequences of the alignment or discriminative between groups of sequences. These blocks are used to generate profile HMMs, which can in turn be used, in the context of virology, to identify broad taxonomic groups, such as viral families, or narrower taxa as genera or viral species. The present project aimed to apply and standardize the use of TABAJARA in different taxonomic groups of viruses, to build specific models for each of these groups and to validate these models in metagenomic data. We used three viral models for this study. The first chosen model was the Bunyavirales order, composed of mostly enveloped and spherical ssRNA(-) viruses with a segmented genome belonging to group 5 of the Baltimore classification. This group includes viruses that cause several important diseases in humans, animals and plants. The second chosen model was the Togaviridae family, composed of enveloped and spherical ssRNA(+) viruses, with a genome coding for a polyprotein, and belonging to group 4 of the Baltimore classification. This group includes the Chikungunya virus and some other viral species that cause relevant pathologies to humans and animals. Finally, we used the Spounavirinae subfamily, comprising viruses that infect a variety of bacterial hosts and that can potentially be used for phage therapy of some human bacterial diseases. These phages present non-enveloped virions with a head-to-tail structure, a dsDNA genome, and belong to group 1 of the Baltimore classification. All constructed profile HMMs were evaluated in regard to their sensitivity and specificity of detection, as well as tested in viral surveys using metagenomic data from the SRA database. The profile HMMs presented excellent performance, proving the viability of the methodology proposed in this project. The results presented in this work open the perspective of the wide use of profile HMMs as universal tools for the detection and classification of viruses in metagenomic data.

HMMs de perfil são um método poderoso para modelar a diversidade de sequências biológicas e constituem uma abordagem muito sensível para a detecção de ortólogos remotos. Uma potencial aplicação de tais modelos é a detecção de vírus emergentes e novos elementos genéticos móveis. Nosso grupo desenvolveu recentemente o GenSeed-HMM, um programa que emprega HMMs de perfil como sementes para montagem progressiva de genes-alvo, utilizando tanto dados genômicos como metagenômicos. No presente trabalho foi desenvolvido o TABAJARA, um programa para o desenho racional de HMMs de perfil. Partindo de um alinhamento de múltiplas sequências, o TABAJARA é capaz de encontrar blocos que são (1) conservados ou (2) discriminativos para dois ou mais grupos de sequências. O programa utiliza diferentes métricas para atribuir pontuações posição-específicas ao longo de todo o alinhamento e utiliza então uma janela deslizante para encontrar as regiões com maiores pontuações. Blocos de alinhamento selecionados são então extraídos e utilizados para construir HMMs de perfil. Para validar o método, o programa TABAJARA foi empregado para a construção de modelos para vírus do gênero Flavivirus e para fagos da família Microviridae. Em ambos os grupos virais foi possível se obter modelos de ampla abrangência, capazes de detectar todos os membros de um respectivo grupo taxonômico, e modelos de abrangência mais restrita, específicos para espécies distintas de Flavivirus (ex. DENV, ZIKV ou YFV) ou subfamílias de Microviridae (ex. Alpavirinae, Gokushovirinae e Pichovirinae). Em outra validação, foram utilizadas sequências da endonuclease Cas1 para se obter modelos capazes de diferenciar CRISPRs de casposons, esses últimos representando uma superfamília de transposons de DNA autossintetizantes, os quais originaram o sistema de imunidade CRISPR-Cas de procariotos. O TABAJARA conseguiu gerar modelos específicos de Cas1 derivada de casposons, permitindo sua diferenciação em relação aos seus ortólogos de CRISPRs. No presente trabalho foi desenvolvido ainda o HMM-Prospector, uma ferramenta que utiliza um conjunto de HMMs de perfil para a triagem de dados de sequenciamento genômico ou metagenômico. O programa informa quais são os modelos mais reconhecidos pelas leituras, sob valores de corte de pontuação definidos pelo usuário, assim como quantas leituras são detectadas por cada modelo. Com esta informação, os modelos mais relevantes podem ser utilizados como sementes em montagens progressivas com o programa GenSeed-HMM, dentro de uma abordagem integrada para a construção de modelos e sua aplicação. Finamente, foi desenvolvido o e-Finder, um aplicativo genérico para a detecção e extração de elementos multigênicos a partir de genomas ou metagenomas montados utilizando HMMs de perfil. O e-Finder executa buscas de similaridade entre os HMMs de perfil e as sequências traduzidas dos dados montados e checa, em seguida, se os critérios de sintenia pré-definidos foram atendidos, incluindo o número mínimo de genes, a ordem dos genes e as distâncias intergênicas. As sequências dos elementos são então extraídas, as regiões codificantes (ORFs) identificadas e traduzidas conceitualmente em sequências completas de proteínas. Para validar esta ferramenta, foram empegados dois estudos de caso, profagos da família Microviridae e casposons, utilizando-se HMMs de perfil específicos, construídos com o programa TABAJARA. Em ambos os casos, o e-Finder foi executado usando-se a base de dados PATRIC, um repositório com mais de 135.000 genomas de bactérias e arqueias. Foram identificados um total de 91 contigs positivos para casposons a partir de 79 genomas distintos. No caso dos Microviridae, foram encontrados 104 profagos candidatos, estendendo o conhecimento da gama de hospedeiros bacterianos. Em ambos os casos, análises filogenéticas confirmaram a correta atribuição taxonômica das sequências positivas. Os programas desenvolvidos neste trabalho podem ser utilizados isoladamente ou em combinação para detectar e discriminar sequências conhecidas ou remotamente relacionadas. Juntamente com o GenSeed-HMM, estes programas constituem um conjunto integrado de ferramentas com potencial aplicação na busca de novos vírus e elementos genéticos móveis, bem como em qualquer outra tarefa relacionada à detecção e/ou discriminação de subgrupos de famílias de sequências nucleotídicas ou proteicas / Profile HMMs are a powerful way of modeling sequence diversity and constitute a very sensitive approach to detect remote orthologs. A potential application of such models is the detection of emerging viruses and novel mobile genetic elements. Our group has recently developed GenSeed-HMM, a tool that employs profile HMMs as seeds for gene-targeted progressive assembly using either genomic or metagenomic data. In this work we developed TABAJARA, a program for the rational design of profile HMMs. Starting from a multiple sequence alignment, TABAJARA is able to find blocks that are either (1) conserved across all sequences or (2) discriminative for two or more specific groups of sequences. The program uses different metrics to ascribe position-specific scores along the whole alignment and then uses a sliding-window to find top-scoring regions. Selected alignment blocks are then extracted and used to build profile HMMs. To validate the method, we employed TABAJARA to construct models for viruses of the Flavivirus genus and phages of the Microviridae family. In both viral groups we were able to obtain wide-range models, able to detect all members of the respective taxonomic group, and models that are specific to particular Flavivirus species (e.g. DENV, ZIKV or YFV) or Microviridae subfamilies (e.g. Alpavirinae, Gokushovirinae and Pichovirinae). In another validation, we used sequences of the endonuclease Cas1 to obtain models capable of differentiating CRISPRs from casposons, the latter elements representing a superfamily of self-synthesizing DNA transposons that originated the prokaryotic CRISPR-Cas immunity. TABAJARA succeeded to generate models specific to casposon-derived Cas1, enabling their differentiation from CRISPR orthologs. We also developed HMM-Prospector, a tool that can use a batch of profile HMMs to screen genomic or metagenomic sequencing data, reporting which profile HMMs are mostly recognized under user-defined score cutoff values, and how many reads are detected by each model. With this information, the most relevant models can be used as seeds in progressive assemblies with GenSeed-HMM program, providing an integrated approach for model construction and application. Finally, we developed e-Finder, a generic application for detecting and extracting multigene elements from assembled genomes or metagenomes using profile HMMs. e-Finder runs similarity searches of profile HMMs against translated sequences of the assembled data and then checks if pre-defined syntenic criteria have been fulfilled, including minimum number of genes, gene order and intergenic distances. Element sequences are then extracted, their ORFs identified and conceptually translated into full-length protein sequences. To validate the tool, we employed two distinct case studies, prophages of the Microviridae family and casposons, using specific profile HMMs constructed by TABAJARA. In both cases, we executed e-Finder using the PATRIC database, a repository with over 135,000 bacterial and archaeal genomes. We identified in total 91 casposon-positive contigs from 79 distinct genomes. In the case of Microviridae, we found a total of 104 provirus candidates, extending the known range of bacterial hosts. In both cases, phylogenetic analyses confirmed the correct taxonomic assignment of the positive sequences. The programs developed in this work can be used alone or in combination to detect and discriminate known or distantly related sequences. Together with GenSeed-HMM, these programs provide an integrated toolbox with potential application in the search of novel viruses and mobile genetic elements, as well as in any other task related to the detection and/or discrimination of subgroups of DNA or protein sequences.

Eine der häufigsten viralen Infektionskrankheiten im Kindesalter ist gegenwärtig die Parotitis epidemica. Mit dem Auftreten einer abakteriellen Meningitis bei Kindern als Folge einer Mumpsvirusinfektion ist in über 80% der Fälle zu rechnen. 1. In serologisch bestätigten Mumpsfällen wurden Liquorproben von Kindern mit einer Meningitis immunfluoreszenzoptisch untersucht. In den lympho-monozytären Liquorzellen konnte das Mumpsantigen in 64% der Fälle nachgewiesen werden. 2. Der immunfluoreszenzoptisch Nachweis des Mumpsantigens in Liquorzellen stellt eine Erweiterung der diagnostischen Möglichkeiten bei serösen Meningitiden des Kindes unklarer Äthiologie dar. 3. Während der Prüfung von Mumpsviren reagieren intracerebral infizierte Affen mit einer statistisch gesicherten Erhöhung der Liquorzellzahl. Bei Affen, die mit einer neuropathogenen Variante infiziert waren, sind die Liquorzellzahlen auch 28 Tage p.i. signifikant höher im Vergleich zu mit Impfstoff infizierten Tieren. Der Nachweis des Mumpsantigens in den Liquorzellen beweist die Spezifität der experimentellen Mumpsmeningitis bei Affen. Das virale Antigen wird nur innerhalb der ersten Versuchswoche in den Liquorzellen detektiert, nach 3 – 4wöchiger Versuchsdauer ist das Mumpsvirus im Liquor der Affen nicht mehr nachweisbar. Diese Befunde sind mit den Befunden bei natürlichen Mumpsmeningitiden der Kinder vergleichbar. 4. Minischweine und Katzen reagieren auf intracerebral appliziertes Mumpsvirus mit charakteristischen liquorzytologischen Veränderungen, die mit den Befunden beim Affen korrelieren. Sie reagieren auf intracerebral inokuliertes Mumpsvirus bereits in der ersten Woche mit einer deutlichen Liquorpleozytose. Die Höhe der Zellzahl im Liquor ist bei Mumpswildviren (α = 0,05) bedeutend größer als bei den Impfviren. Die Zellzahlerhöhung ist nach 8 Wochen nicht auf die Normalwerte zurückgegangen. 5. Der immunfluoreszenzoptische Nachweis des Mumpsantigens in den Liquorzellen der Minischweine und Katzen ist zeitlich begrenzt. Es ergaben sich Unterschiede zwischen Mumpsviren vom Wild- und Impftyp. Der Nachweis des viralen Antigens in den Liquorzellen war 4 Wochen p.i. nicht mehr möglich. 6. Das Differentialzellbild des Liquors ist bei allen Tiermodellen durch lympho-monozytäre Zellen gekennzeichnet, wobei monozytäre Zellformen zu jedem Zeitpunkt der Infektion überwiegen. 7. Vor der Anwendung von Lebendimpfstoffen beim Menschen ist eine tierexperimentelle Sicherheitsprüfung notwendig. Die Einbeziehung der Liquordiagnostik (Verlauf der Pleozytose und der fluoreszenzoptische Antigennachweis in den Liquorzellen) ist eine wesentliche Ergänzung zur Charakterisierung der neurotropen Eigenschaften des viralen Mumpsantigens. / One of the most common viral infectious diseases in childhood is currently parotitis epidemica. The occurrence of abacterial meningitis in children as a result of mumps virus infection can be expected in more than 80% of cases. 1. In serologically confirmed mumps cases, cerebrospinal fluid samples from children with meningitis were examined by immunofluorescence. Mumps antigen was detected in the lympho-monocytic cerebrospinal fluid (CSF) cells in 64% of cases. 2. Immunofluorescence detection of mumps antigen in CSF cells represents an extension of diagnostic possibilities in serous meningitis of the child of unclear etiology. 3. During mumps virus testing, intracerebrally infected monkeys respond with a statistically confirmed increase in CSF cell count. In monkeys infected with a neuropathogenic variant, CSF cell counts are significantly higher even 28 days p.i. compared with vaccine-infected animals. Detection of mumps antigen in CSF cells demonstrates the specificity of experimental mumps meningitis in monkeys. The viral antigen is detected in the CSF cells only within the first week of the experiment; after 3 - 4 weeks of the experiment, the mumps virus is no longer detectable in the CSF of the monkeys. These findings are comparable to the findings in natural mumps meningitis of children. 4. Minipigs and cats respond to intracerebrally applied mumps virus with characteristic liquor cytologic changes that correlate with the findings in monkeys. They respond to intracerebrally inoculated mumps virus with marked CSF pleocytosis as early as the first week. The level of cell number in CSF is significantly greater in wild mumps virus (α = 0.05) than in vaccine virus. The cell count increase did not return to normal values after 8 weeks. 5. Immunofluorescence detection of mumps antigen in CSF cells of minipigs and cats is temporal. Differences were found between wild-type and vaccine-type mumps viruses. Detection of viral antigen in CSF cells was no longer possible 4 weeks p.i.. 6. The differential cell pattern of CSF is characterized by lympho-monocytic cells in all animal models, with monocytic cell forms predominating at each time point of infection. 7. Animal safety testing is required prior the use of live vaccines in humans. The inclusion of CSF diagnostics (course of pleocytosis and fluorescence antigen detection in CSF cells) is an essential addition to characterize the neurotropic properties of the viral mumps antigen.