Mutant p53 murine oviductal epithelial cells induce progression of high-grade serous carcinoma and are most sensitive to simvastatin therapy in vitro and in vivo

High-grade serous carcinoma (HGSC) is the most common and aggressive subtype of epithelial ovarian cancer, characterized by gain-of-function TP53 mutations originating in the fallopian tube epithelium. Therapeutic intervention occurs at advanced metastatic disease, due to challenges in early-stage diagnosis, with common disease recurrence and therapy resistance despite initial therapy success. The mevalonate pathway is exploited by many cancers and is potently inhibited by statin drugs. Statins have shown anti-cancer activity in many, but not all cancers. Here, we investigated the role of p53 status in relation to mevalonate pathway signaling in murine oviductal epithelial (OVE) cells and identified OVE cell sensitivity to statin inhibition. We found that p53R175H mutant and Trp53 knockout OVE cells have increased mevalonate pathway signaling compared to p53 wild-type OVE cells. Through orthotopic implantation to replicate the fallopian tube origin of HGSC, p53R175H mutant cells upregulated the mevalonate pathway to drive progression to advanced-stage ovarian cancer, and simvastatin treatment abrogated this effect. Additionally, simvastatin was more efficacious at inhibiting cell metabolic activity in OVE cells than atorvastatin, rosuvastatin and pravastatin. In vitro, simvastatin demonstrated potent effects on cell proliferation, apoptosis, invasion and migration in OVE cells regardless of p53 status. In vivo, simvastatin induced ovarian cancer disease regression through decreased primary ovarian tumor weight and increased apoptosis. Simvastatin also significantly increased cytoplasmic localization of HMG-CoA reductase in ovarian tumors. Downstream of the mevalonate pathway, simvastatin had no effect on YAP or small GTPase activity. This study suggests that simvastatin can induce anti-tumor effects and could be an important inhibitor of ovarian cancer progression.

Comparative analysis of syngeneic mouse models of high-grade serous ovarian cancer

Ovarian cancers exhibit high rates of recurrence and poor treatment response. Preclinical models that recapitulate human disease are critical to develop new therapeutic approaches. Syngeneic mouse models allow for the generation of tumours comprising the full repertoire of non-malignant cell types but have expanded in number, varying in the cell type of origin, method for transformation, and ultimately, the properties of the tumours they produce. Here we have performed a comparative analysis of high-grade serous ovarian cancer models based on transcriptomic profiling of 22 cell line models, and intrabursal and intraperitoneal tumours from 12. Among cell lines, we identify distinct signalling activity, such as elevated inflammatory signalling in STOSE and OVE16 models, and MAPK/ERK signalling in ID8 and OVE4 models; metabolic differences, such as reduced glycolysis-associated expression in several engineered ID8 subclones; and relevant functional properties, including differences in EMT activation, PD-L1 and MHC class I expression, and predicted chemosensitivity. Among tumour samples, we observe increased variability and stromal content among intrabursal tumours. Finally, we predict differences in the microenvironment of ID8 models engineered with clinically relevant mutations. We anticipate that this work will serve as a valuable resource, providing new insight to help select models for specific experimental objectives.

Gain-of-function p53R175H blocks apoptosis in a precursor model of ovarian high-grade serous carcinoma

Ovarian high-grade serous carcinoma (HGSC) is a highly lethal malignancy for which early detection is a challenge and treatment of late-stage disease is ineffective. HGSC initiation involves exfoliation of fallopian tube epithelial (FTE) cells which form multicellular clusters called spheroids that colonize and invade the ovary. HGSC contains universal mutation of the tumour suppressor gene TP53. However, not all TP53 mutations are the same, as specific p53 missense mutants contain gain-of-function (GOF) properties that drive tumour formation. Additionally, the role of GOF p53 in spheroid-mediated spread is poorly understood. In this study, we developed and characterized an in vitro model of HGSC based on mutation of TP53 in mouse oviductal epithelial cells (OVE). We discovered increased bulk spheroid survival and increased anchorage-independent growth in OVE cells expressing the missense mutant p53R175H compared to OVE parental and Trp53ko cells. Transcriptomic analysis on spheroids identified decreased apoptosis signaling due to p53R175H. Further assessment of the apoptosis pathway demonstrated decreased expression of intrinsic and extrinsic apoptosis signaling molecules due to Trp53 deletion and p53R175H, but Caspase-3 activation was only decreased in spheroids with p53R175H. These results highlight this model as a useful tool for discovering early HGSC transformation mechanisms and uncover a potential anti-apoptosis GOF mechanism of p53R175H.

Long COVID: health symptoms, impact on health-related quality of life and mapping to disability weights

Introduction

Previous studies indicated that a significant share of COVID-19 patients experiences long lasting health complaints; a condition also referred to as “long COVID”. In order to assess the long term burden of disease of COVID-19, including long COVID, information is needed on health symptoms, health-related quality of life and duration of symptoms of long COVID patients. Therefore, the aim of this study was to assess health symptoms and health-related quality of life of long COVID in the general population of the Netherlands.

Methods

A total of 33,903 COVID-19 patients from the region South-Holland South (the Netherlands) whom tested positive between June 2020 and May 2021 at the municipal health services were invited to complete a web-based questionnaire on the presence, nature and consequences of long COVID and health-related quality of life, measured with the EQ-5D-5L.

Results

In total, 3,768 participants who completed the questionnaire experienced long COVID. Most commonly reporting symptoms were reduced physical condition (65.5%), fatigue (59.6%), problems concentrating (49.6%), loss of smell (41.2%) and shortness of breath (37.8%). 648 participants indicated that they experienced long COVID symptoms for 5 months or longer. Preliminary analysis showed that increasing number of symptoms was associated with a decrease in health-related quality of life.

Discussion and conclusions

Long COVID covers a range of health symptoms of varying severity and duration. This complicates the calculation of the non-fatal burden of disease of COVID-19, particularly because mapping of long COVID to existing disability weights is hampered.

Abstract 2332: Repurposing simvastatin to inhibit the mevalonate pathway as a therapeutic strategy to treat high-grade serous ovarian cancer

Introduction: Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer, and its five-year survival rate has not changed appreciably in decades. As such, there is an imperative need for new and innovative therapies. Our lab has previously discovered that metastatic ascites-derived tumor cells have acquired a gain-of-function p53 mutation following interaction with the ovarian microenvironment in our orthotopic murine model of EOC. This p53 mutation is associated with an upregulation of the mevalonate pathway, which is known for its vital role in producing cholesterol. Tumor cells upregulate metabolic pathways as a survival advantage to fuel their rapid growth and metastasis. Simvastatin, a statin therapy, specifically targets HMG-CoA reductase, the rate-limiting enzyme of this pathway, and inhibits its activity. As such, simvastatin may serve as a potential therapeutic opportunity for EOC. Gain-of-function p53 mutations in the epithelial cells of the distal fallopian tube is now widely accepted as the origin of high-grade serous ovarian cancer. Thus, the purpose of our study was to investigate the relationship between p53 status and the mevalonate pathway in oviductal epithelial (OVE) cells as well as evaluate the effect of simvastatin treatment on OVE cell viability.

Methods/Results: OVE cells were isolated from the distal oviducts of FVB/N mice with a p53 wildtype status, and we either deleted the Trp53 gene or introduced a gain-of-function R175H p53 mutation using CRISPR/Cas9. Cell viability was measured following treatment with varying doses of simvastatin and p53 mutant cells showed the greatest sensitivity (IC50: 5.48 uM) compared to p53 wildtype (IC50: 14.80 uM) and p53 knockout (IC50:9.78 uM) cells. For subsequent experiments, OVE cells were treated with 10 uM simvastatin or DMSO and subjected to Resazurin, Transwell migration, CyQUANT proliferative and Caspase-Glo 3/7 assays. Simvastatin significantly decreased resazurin reduction to resorufin in a time-dependent manner over 48 hours, regardless of p53 status, demonstrating reduced metabolic activity. Additionally, OVE cell invasion was significantly reduced in simvastatin treated p53 mutant cells, compared to p53 wildtype or p53 knockout cells. Simvastatin treatment diminished cell proliferation and enhanced apoptotic activity in all simvastatin treated OVE cells.

Conclusion: Overall, simvastatin appears to inhibit tumorigenic processes in vitro. The next steps of this project are to test simvastatin’s effect on disease regression in a novel murine oviductal cell injection model of EOC recently developed by our lab. In light of these results, repurposing simvastatin as a therapy for ovarian cancer may significantly improve the way we treat this vicious disease.

Citation Format: Madison Pereira, Kathy Matuszewska, Jacob Haagsma, Alice Glogova, Trevor G. Shepherd, Jim Petrik. Repurposing simvastatin to inhibit the mevalonate pathway as a therapeutic strategy to treat high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2332.

Quantification of injury burden and barriers in maintaining quality data

For policy-makers, quantification of the burden of injury and the determination of the relative attributes of avoidable risk factors to this burden are vital tools for priority-setting purposes. This is particularly important in the case of a rapidly changing injury landscape due to effects of the COVID-19 pandemic. Following the 1996 Global Burden of Disease study the disability adjusted life year (DALY) is widely used to assess the burden of injury. The DALY is a population health metric that expresses health loss due mortality, morbidity and disability into a single number. This allows comparisons of distinct health outcomes across subgroups of a population and over time. In addition, cost-of-illness studies can be used to assess the societal burden of injury. Cost-of-illness studies may vary with regards to the time horizon that is used as well as the cost components, which may include intramural and extramural costs as well as productivity loss due work absenteeism due to injury. Essential for the calculation of injury DALYs and cost-of-illness is relevant data on the occurrence of injury, injury deaths, data on exposure to risk factors for injuries, health care consumption and return to work. However, each phase of the pandemic posed different barriers maintaining collection of quality data which may subsequently jeopardize accurate injury DALY calculations and determination of the relative attributes of avoidable risk factors during the COVID-19 pandemic.

A systematic literature review of burden of disease studies in Europe: next steps and implications for researchers

Facing the considerable variation in the computation of disability-adjusted life years (DALY), the European Burden of Disease Network (burden-eu) launched a series of systematic literature reviews (SLR) to explore the key variations in the assumptions used in the European burden of disease (BoD) assessments. The studies were evaluated in terms of pre-defined criteria, focusing on data sources used and on specific methodological and normative choices to assess BoD. Preliminary results show a wide variety in methodological assumptions used to quantify DALYs, but also important inconsistencies in the reporting of methods and particular assumptions. For instance, the quantification of uncertainties is not a common practice, even though most authors seem to be aware of the uncertainty in their DALY estimates and discuss uncertainties as an important study limitation. When uncertainties were quantified, different approaches were used, and described using inconsistent nomenclature. The results of the SLR show that there is a clear need for standardized reporting guidelines for DALY estimates. Such a tool could be based on quality assessment checklists already in place for clinical trials and observational studies (PRISMA, STROBE, CRD), and would require inclusion of the DALY's key methodological and normative choices. Standardized DALY reporting guidelines could serve multiple purposes. First and foremost, they would allow to increase the quality of reporting, thereby increasing the transparency and comparability of BoD studies. As a reference document, such guidelines would also help to harmonize nomenclature, which would further increase transparency and comparability. Last but not least, it would also serve as a capacity building tool, supporting researchers in understanding which methods and assumptions underlie the DALY metric. To address this need, the burden-eu network aims to play a driving role in the development of standardized DALY reporting guidelines.

A systematic literature review of studies estimating the risk factor attributable burden in Europe

Along with the computation of disability-adjusted life years (DALY), the Global Burden of Disease (GBD) study uses the comparative risk assessment method to estimate the burden attributable to risk factors (RF). The methodology used for GBD studies has undergone continuous improvements through the years and across many independent studies. The European burden of disease network launched a series of systematic literature reviews (SLR) to explore key assumptions used in the European burden of disease (BoD) assessments. The SLR will give an overview of existing studies, including those estimating the BoD attributable to RF and focus on the different computational approaches. The SLR will also help to identify ways to harmonize computational procedures to enhance the comparability of RF attributable burden. The SLR involved four parallel reviews: non-communicable diseases, communicable diseases, injuries and RF. For the latter, we used a search strategy with terms describing the population (GBD area “European region”) and terms specifically used in comparative risk assessments (comparative risk assessment [CRA], attributable mortality/burden/risk). Studies published between January 1990 and April 2020 were included, without language restrictions. The search strategy was run in PubMed, Web of Science, Cochrane, and Embase. OpenGrey, OAIster, CABDirect, WHO, and targeted public health agency websites were screened for indexed grey literature. In addition, burden-eu members were asked to supplement the list of publications with any material available in their national public health institutes. The title, abstract, and full-text screening resulted in the final inclusion of 114 publications. The list of publications includes peer-reviewed articles and reports showing a variability in CRA analysis (e.g. use of exposure-response function, relative risks) and other methodological choices. Further data extraction and analysis is in process and will be presented during the workshop.

An overview of burden of disease studies in Europe

Facing the considerable variation in the computation of disability-adjusted life years (DALY) in the numerous updates of the Global Burden of Disease (GBD) study and many independent studies, the European burden of disease network (burden-eu) launched a series of systematic literature reviews (SLR) to explore the key assumptions used in the European burden of disease (BoD) studies. The SLR will provide an overview of the existing BoD studies and the computational variations used and will also help identifying ways to harmonize the approaches enhancing the comparability of BoD estimates. The SLR was split in four parallel reviews: non-communicable diseases (NCDs), communicable diseases (CDs), injuries and risk factors. For the first three, the search strategy included terms describing the population (GBD area “European region”) and the BoD measures (years lived with disability, years of life lost, and DALYs). We included studies published between January 1990 and April 2020, without language restrictions. The search strategy was run in PubMed, Web of Science, Cochrane, and Embase. OpenGrey, OAIster, CABDirect, WHO and targeted public health agency websites were screened for grey literature. In addition, burden-eu members were asked to supplement the list of publications with any material available within their national public health institutes. Data extraction focused on methodological information. The title, abstract and full-text screening resulted in the final inclusion of 165 papers regarding NCDs, 189 with CDs, and 124 papers regarding injuries. The final list includes peer-reviewed articles and reports showing a variability in data sources used (e.g. patient medical records, disease registries, insurance claims sources) and model assumptions (e.g. use of multi-morbidity adjustments, use of disability weights). Further data extraction and analysis is in process, and will be presented during the workshop.

Data inputs and assumptions in calculating the non-fatal burden in burden of disease studies

Years Lived with Disability (YLD) is a component of the Disability-Adjusted Life Year (DALY), and measures the healthy time that is lost because of living with a disease or disability. YLDs are calculated by multiplying the prevalence and/or incidence of a disorder by the short- or long-term loss of health associated with that disability (the disability weight) and disease severity (severity distribution).

The process of calculating a YLD involves several components and in this presentation each step will be highlighted through a sequential walk through for each step in the YLD calculation, including counting disease occurrencethe relationship between disability weights, health states and severity distributionsadjusting for comorbiditiesdealing with uncertainty

The aim of this presentation is to provide a simple step by step guide on the key components in the YLD calculation. Using the real-life example of cerebrovascular disease, the presentation will outline the key choices and assumptions that underline each data input in the YLD calculation. Participants in this session will also be provided with links to resources to help facilitate this decision-making process. The workshop will end with an interactive session where the presenters will discuss the implications of the different methodological choices with the audience.

Unscattering the burden of disease landscape: supporting interaction between existing burden of disease efforts

The burden of disease landscape in Europe is currently scattered with experts from diverse professional backgrounds, ranging from experts in infectious diseases, non-communicable diseases, injuries and risk factors, to experts in more comprehensive national, regional and global burden of disease studies. Currently there is little interaction between these experts and existing burden of disease efforts. The European burden of disease network (burden-eu) COST Action aims to bring together expertise across different domains and professional backgrounds. During the course of the burden-eu COST Action, several steps will be taken to facilitate interaction between existing burden of disease efforts. First, a survey has been sent around to all members of the EU burden of disease network to map burden of disease studies that have been carried out in their country. Apart from general details about the year of the study and cause of disease categories, items of the survey included data sources, methodological approach and collaborations with institutes of other countries. In the first month, the survey has been completed for over 70 studies that have been carried out in twelve countries. Second, comparison of existing burden of disease initiatives allows for the identification of the various domains for which burden of disease has been assessed, highlight methodological differences as well as similarities, and

facilitate improvements and harmonization of methods and approaches. Furthermore, the data collected from the survey will be included in a continuously updated burden of disease database that lists all past and current burden of disease activities. Lastly, burden-eu will facilitate regular meetings and workshops. Each of these steps will make it possible to move beyond the currently scattered burden of disease landscape and increase interaction between professionals and burden of disease efforts.

A comparison of the potency of several Brucella allergens used to detect brucellosis in cattle

The potency of Brucella allergens prepared from a smooth Brucella abortus strain S-99, mucoid strain Leewarden, rough strain 45/20, and rough Brucella melitensis strain B-115 was assessed. The potency of these allergens was compared with that of a standard allergen prepared from smooth Brucella abortus S-99 that efficiently detected bovine brucellosis in other studies. Eight cattle experimentally inoculated with Brucella abortus 544 were tested with the allergens 4 and 10 weeks after infection, and again 8 months after infection. All the allergens effectively detected infection but there was a clear distinction in the mean skin reactions 48 and 72 h after injection of the allergens. The skin reactions provoked by the allergens prepared from smooth or mucoid strains of Brucella were most pronounced 48 h after injection. Skin reactions provoked by allergens prepared from rough strains of Brucella were strongest 72 h after injection. Allergens prepared from smooth or mucoid Brucella strains were more potent in detecting brucellosis than those prepared from rough strains of Brucella.

Novel glycolipids of Mycobacterium avium and related M. paratuberculosis strains of relevance to AIDS and Crohn's disease

The polar glycolipid fractions of several mycobacterial strains of the closely related species M. avium and M. paratuberculosis have been analysed by thin layer chromatography (TLC), high pH anion exchange chromatography (HPAEC), gas-liquid chromatography (GC) and nuclear magnetic resonance (NMR) spectroscopy. The upper phase of a Folch partitioning (rather than the lower phase analysed by others) was subjected to TLC in solvent system chloroform-methanol-water 50:40:10 v/v/v. A major band was purified from each mycobacterial strain. Monosaccharide analysis of that from M. avium A14 (from an AIDS patient) contained Glc, Ara, Man, Gal in ratios 7:4:3:2. whereas one strain of M. paratuberculosis (316F) had low levels of Ara, Gal and Man with major monosaccharides being Glc and two unidentified monosaccharides. A second M. paratuberculosis strain (J10) had a single TLC band containing only Glc. These known strains were compared to two slow growing mycobacterial isolates, one from a Crohn's patient and one isolated from armadillo. These were similar to J10 in only having Glc present: the former also had a similar NMR spectrum to J10, whereas the latter had a different NMR spectrum from any of the other strains analysed. The results therefore indicate that M. paratuberculosis strain 316F is more closely related to M. avium (from an AIDS patient) than it is to the classical M. paratuberculosis strain J10 and a Crohn's isolate.

Production of Brucella allergens and evaluation of their biological activity in a guinea-pig bio-assay

A study was conducted to evaluate the biological activity of Brucella allergens extracted with hydrochloride or trichloroacetic acid. Smooth and mucoid Brucella abortus cells and the medium in which brucellae were propagated were used to prepare the allergens. The biological activity of the allergens was estimated in guinea-pigs sensitized with Brucella abortus strain 544. The guinea-pigs were intradermally injected with several allergen dilutions. The dilutions were coded and randomized for site of injection so that none of the dilution was injected twice on the same site. Variance analysis using incomplete Latin square was used for the statistical calculation of the results. The calculated biological activity of the allergens was compared with the biological activity of a 'standard' allergen that has proved effective in detecting cattle brucellosis. The skin erythema diameter was best when recorded 32 h after allergen injection. Statistical analysis of the skin erythema diameters showed a great variation in biological activity (12-105%) between the allergens. Only the allergen extracted from the medium in which a mucoid Brucella strain was propagated was as potent as the standard. The use of the incomplete Latin square for variance analysis resulted in the estimation of the biological activity of nine batches of allergen in only 27 guinea-pigs.

Use of various genetic markers in differentiation of Mycobacterium bovis strains from animals and humans and for studying epidemiology of bovine tuberculosis

One hundred fifty-three Mycobacterium bovis strains from cattle, various animal species from zoos and wild parks, and humans were analyzed for three different genetic markers for use in the epidemiology of bovine tuberculosis. M. bovis strains isolated from cattle were found to carry a single IS6110 element, whereas the majority of strains from other animals such as antelopes, monkeys, and seals harbored multiple IS6110 elements, suggesting that the reservoirs in cattle and wild animals are separated. Because the single IS6110 element in cattle strains is located at the same chromosomal position, strain differentiation by insertion sequence fingerprinting was hampered. Therefore, we investigated the usefulness of the direct repeat and polymorphic GC-rich repeat elements for strain differentiation. Both markers allowed sufficient strain discrimination for epidemiological purposes. Evidence is presented that in Argentina, most human M. bovis infections are due to transmission from cattle, whereas M. bovis infections among humans in the Netherlands are mainly contracted from animals other than cattle. Various outbreaks of M. bovis among animals and humans are described, including a small one which likely involved transmission from human to human.

Production of Apx toxins by field strains of Actinobacillus pleuropneumoniae and Actinobacillus suis

The three Apx toxins of Actinobacillus pleuropneumoniae have potential value for use in vaccines and diagnostic tests which will be species specific instead of serotype specific, provided that the Apx toxins are species specific and all field strains produce these toxins. We examined 114 A. pleuropneumoniae field strains and found that they secreted either ApxI, ApxII, ApxI and ApxII, or ApxII and ApxIII and secreted no other cytolytic activities. However, proteins similar to ApxI and ApxII were also produced by Actinobacillus suis.

An outbreak of tuberculosis in a captive herd of Arabian oryx (Oryx leucoryx): diagnosis and monitoring

An outbreak of tuberculosis induced a mortality of 25 per cent in a captive herd of Arabian oryx (Oryx leucoryx). The diagnostic screening tests used on live animals included the comparative skin test, indirect and comparative ELISA tests and lymphocyte transformation tests. Difficulties in the interpretation of these tests stemmed principally from the facts that false negatives and false positives were encountered and that the threshold of positivity was difficult to establish with the ELISA test. The presence of other mycobacterial infections in the environment was almost certainly a complicating factor.

Specificity of the skin delayed-type hypersensitivity test in brucellosis free cattle tested with a Brucella allergen

A study was conducted to determine possible nonspecific skin delayed-type hypersensitivity (SDTH) test reactions in cattle tested with a Brucella allergen. Cattle (n = 14) experimentally inoculated with microorganisms known serologically to cross-react with Brucella and cattle (n = 549) from Brucella free herds were tested serologically and with the SDTH test. The increase in skinfold thickness at the injection site of the allergen was measured to the nearest mm with calipers 48 hours after injection. The results show that none of the SDTH test reactions in cattle experimentally inoculated with microorganisms other than Brucella exceeded 2.0 mm. This indicates that an increase in skinfold thickness > or = 2.0 mm can be considered a positive SDTH test reaction. When this norm was applied to cattle in Brucella free herds 11/549 (2%) cattle showed an increase > or = 2.0. It is concluded that infections with microorganisms other than Brucella are unlikely to cause sensitization that interferes with the SDTH test when used to detect brucellosis. Therefore, the SDTH test can be used to verify positive serologic tests results that might have been caused by microorganisms that serologically cross-react with Brucella.

[An outbreak of bovine tuberculosis on a dairy farm]

An outbreak of bovine tuberculosis on a dairy farm is described. Following intradermal tuberculination 84 animals out of 111 animals older than 6 weeks had a positive reaction. Of the 34 adult sheep one gave a positive reaction. All animals on the farm were taken over for destruction by the Animal Health Centre. The source of the infection could not be established although there was a strong suspicion that the importation of three older dairy cows had introduced the infection on the farm. A further investigation was done on 45 farms. Two of these farms were infected by buying animals from the dairy farm in question. During the investigations the possible transmission of the infections to people who were in close contact to the infected animals was also investigated. From 35 examined persons 5 had a positive Mantoux-reaction. The outbreak coincided with a political discussion concerning the abolishment of the periodical tuberculination on dairy farms. Since 1 January 1993 the surveillance of bovine tuberculosis in the Netherlands is done by import control and findings in slaughter-houses combined with a good identification system. It is stressed that the examinations of the lymph glands in the slaughter-houses require the necessary attention.

Rapid detection and identification of Mycobacterium avium by amplification of 16S rRNA sequences

An assay that is based on the amplification of 16S rRNA sequences and that was initially developed to detect Mycobacterium paratuberculosis in cattle was used to test 20 serotypes of the Mycobacterium avium complex (MAC) and atypical mycobacterial species not belonging to MAC. Only serotypes 1 to 6 and 8 to 11, designated M. avium, were detected by the assay, indicating that it can be used for the rapid detection and identification of M. avium. The results of the assay for clinical samples from animals suspected of having mycobacterial infections indicated that it can also be used directly on clinical samples.

Paratuberculosis in farmed red deer (Cervus elaphus) in Ireland

Paratuberculosis was diagnosed in one 18-month-old and two 30-month-old hinds in a herd of 70 red deer (Cervus elaphus) in Ireland. Loss of condition and intermittent diarrhoea were the main clinical findings. Clumps of acid-fast organisms were found in the faeces of the three deer. Post mortem examination of one deer showed a slight swelling and pallor of the intestinal tract and associated lymph nodes. Histopathology showed a severe, granulomatous enteritis and lymphadenitis, with extensive cellular infiltration, notably with epithelioid macrophages containing numerous acid-fast organisms. Mycobacterium paratuberculosis was isolated from intestinal and lymph node samples. Paratuberculosis was also confirmed in one of nine clinically normal, yearling stags, sampled at slaughter. Complement fixation tests and enzyme-linked immunosorbent assays gave higher readings for clinically affected deer than healthy ones. Acid soil on the farm was believed to be a contributory cause.

Epidemiology and control of rabies in bats in The Netherlands

The first case of bat rabies in the Netherlands was recorded in 1987. Since then, 2,540 bats have been examined. In total, 186 bats belonging to two species were found positive for rabies: 182 Eptesicus serotinus and 4 Myotis dasycneme. The virus isolates from the two species were found to be different. Approximately 20% of the E. serotinus bats sent for examination were found positive. The epidemiological findings suggest a stable situation of infection north of the Rhine and the Meuse. A total of 174 humans received post-exposure treatment after direct contact with a positive or suspected bat. The public has been warned not to touch bats and, if contact does occur, to send the bat for rabies examination. The authorities also advise post-exposure treatment for dogs and cats which have had contact with a rabies-positive bat.

Amplification of 16S rRNA sequences to detect Mycobacterium paratuberculosis

A probe based on 16S ribosomal RNA (rRNA) sequences was developed to detect Mycobacterium paratuberculosis, the causative agent of Johne's disease in cattle. Three universal primers were used to sequence the amplified fragments of the 16S rRNA gene of various species of mycobacteria. When the nucleotide sequences were analysed, a deletion was detected in the sequence of the fast-growing species. An oligonucleotide probe (P) directed to this region was synthesised and hybridised directly with total RNA of various mycobacterial strains in a dot-spot assay. The probe detected M. paratuberculosis, some other slow-growing mycobacteria of the M. avium-intracellulare (MAI) complex, and one atypical strain, M. gordonae. To increase the sensitivity of the probe, a 413-bp fragment of the 16S rRNA gene of M. paratuberculosis between P and a second oligonucleotide primer was amplified and hybridised with a M. paratuberculosis/M. avium-specific probe. When faecal samples of cattle were tested, all culture-positive samples were positive in the PCR assay.

Evaluation of the abilities of three diagnostic tests based on the polymerase chain reaction to detect Mycobacterium paratuberculosis in cattle: application in a control program

Three assays for the specific detection of Mycobacterium paratuberculosis by dot spot hybridization of polymerase chain reaction products were applied to fecal samples of dairy cattle. The first two tests used polymerase chain reaction primers and a DNA probe derived from M. paratuberculosis-specific sequences of the 16S rRNA gene and insertion element IS900, respectively. These two tests were carried out on spiked fecal samples to determine the detection limits. The 16S rRNA test was able to detect 10(7) bacteria per g of feces, and the IS900 test detected 10(4) to 10(5) per g of feces. Next, we studied the usefulness of these tests in a control program for paratuberculosis. Therefore, the tests and a third, commercially available, test (IDEXX Corp.) were used twice with an interval of 3 months on fecal samples of 87 cows from two dairy herds with a history of Johne's disease. We compared the results of these tests with those of culturing. This showed that the tests are specific but that the sensitivity ranged from 3 to 23%. Further improvement of the sensitivity is needed before the tests can be used in a control program to eradicate Johne's disease.

[Mortality of cattle following feeding of moldy flower bulbs]

Five of eight meat cattle died suddenly without showing prior symptoms of disease. The sudden death occurred in connection with the feeding of mouldy tulip bulbs. A short review is given of the use of flower bulbs as cattle feed, the use of herbicides/fungicides in bulb cultivation, and the relevant legislation. Several toxicological aspects that should be taken into consideration when flower bulbs are used as cattle feed are discussed. Both the Central Veterinary Institute and the State Institute for Public Health and Environmental Hygiene showed, in experiments with mice, the presence of a toxin in extracts of the mouldy tulip bulbs. This toxin is probably produced by moulds present in the tulip bulbs. The death of the animals was probably caused by an as yet unidentified mycotoxin.

Pathogenic anaerobic bacteria and the environment

The distribution of pathogenic anaerobes in the environment and the relationship with diseases in animals are discussed. A distinction between the spore-bearing anaerobes (clostridia) and the Gram-negative non-spore-forming anaerobes is necessary. The main habitat of clostridia is the soil but they are also found in dust, sewage, rivers, lakes, sea water, milk, vegetables, fresh meat, fish, insects and the intestinal tract. The Gram-negative non-spore-forming anaerobic bacteria are also widely distributed among animals, principally on mucous membranes of the alimentary tract. After a general introduction and a section on the isolation of anaerobes, the various diseases caused by clostridia (botulism, tetanus, blackleg, malignant oedema, infectious necrotic hepatitis, enterotoxaemia and gas gangrene) and Gram-negative anaerobes (infections due to Fusobacterium and Bacteroides spp., such as diphtheria, footrot, etc.) are discussed. In particular, information concerning the reservoir of the causative agent and the mode of transmission is presented.

[Botulism in cattle, a review]

Botulism in cattle is reviewed in the present paper. General information concerning the aetiology and symptomatology of the disease is followed by a discussion of the epidemiological situation in the Netherlands. Since 1975 several outbreaks of botulism type C or D have occurred. Poultry litter in which toxic carcasses were present, was the most important source of the toxin. An increasing number of cases of botulism type D was reported in recent years, which was probably due to the fact that poultry is not susceptible to toxin type D and therefore the presence of type D toxin is difficult to recognise timely. In addition, atypical cases of type B botulism occurred in the Netherlands during the period from 1977 to 1978, which were caused by supplementary feeding of brewer's grains. Finally, the diagnostic problems, differential diagnosis, prevention, treatment and public health aspects are discussed.

[Tuberculosis in alpacas; a zoonosis as an imported disease]

In the Netherlands, in 1988, a micro-epidemic of tuberculosis in alpacas recently imported from Peru prompted health authorities to initiate investigation of human and animal contacts. Although the animal trainer and his assistant suffered from pulmonary tuberculosis, they turned out to be infected by Mycobacterium tuberculosis, while the animals later proved to be infected by M. bovis. The alpacas' caretaker and a laboratory technician present at the autopsy, were probably infected by animal contact. Elsewhere in the country, three more alpacas were reported with tuberculosis at the time; this initiated a large-scale investigation among alpacas, llamas etc., but no further cases were detected. The possibility of imported zoonoses, especially after 1992, is discussed.

[Tuberculosis in imported alpacas--a zoonosis--now what?]

An outbreak of tuberculosis caused by M. bovis in imported Alpaca's in the Netherlands is reported. A review of the outbreak of the disease is followed by a more detailed discussion of the symptoms, diagnostic testing with the tuberculin skin test and the ELISA test, the gross lesions, the bacteriological examinations, the control measures and the legal aspects. As tuberculosis is not referred to in the Live-Stock Act, the control measures had to be based on the humane Control of Infectious Disease and Tracing the Causes of Disease Act. In the discussion, it is advocated to pay attention to more species of animals than only to the traditional live-stock in the proposed Health and Welfare of Animals Act.

Use of delayed-type hypersensitivity test to diagnose brucellosis in calves born to infected dams

Calves (n = 2) born to dams with experimentally induced brucellosis, and calves (n = 4) born to dams with naturally occurring infection were examined by the delayed-type hypersensitivity (DTH) test for possible B. abortus infection. The results were compared with the serum agglutination test, complement fixation test, and Coombs test. Five calves were nursed by their dams for 8-10 weeks after birth. One calf was separated from its dam and fed artificial milk. Three to five months after birth, four calves tested seropositive in the serologic tests. Antibodies were detected in one calf as early as 1 week after birth. The calf fed on artificial milk was seronegative 4-5 weeks after birth. All calves reacted to the DTH test antigen from week 12 until the end of the experiment, even though serologic tests were negative. We conclude that the DTH test is a valuable technique for diagnosing Brucella in calves born to infected dams.

Testing strains of Clostridium perfringens type A isolated from diarrhoeic piglets for the presence of the enterotoxin gene

A diarrhoeic syndrome in piglets has been linked to Clostridium perfringens type A because this organism has been isolated in large numbers from all cases. The strains isolated from these cases and strains isolated from healthy piglets were screened for the enterotoxin gene of C perfringens by DNA-hybridisation. Using two different synthetic DNA-probes, none of the strains isolated from diseased pigs was positive in this reaction, indicating that the enterotoxin of C perfringens is not involved in the syndrome.

Avian tuberculosis in wild birds in the Netherlands

Mycobacterium avium was isolated from 82 of 11,664 birds submitted for necropsy in The Netherlands. All isolated M. avium strains belonged to serotype 1, 2 or 3. The greatest number M. avium were from buzzards and falcons. The prevalence of tuberculosis in gulls is extremely low.

[Diagnosis and control of tuberculosis in cattle]

The current knowledge of the diagnosis and treatment of tuberculosis in cattle is reviewed as part of a series bearing the title 'Papers in the Past and Present'. A retrospective view is taken of the discovery of tuberculin by Robert Koch in 1890 and of three papers by Professor M.H.J.P. Thomassen, which appeared shortly after: 'Koch's Discovery and its Diagnostic Value to Veterinary Medicine'. A review of developments in the use of the tuberculin test and the methods used in the control of tuberculosis as well as reference to some bacteriological data is followed by a more detailed discussion of the pathogenesis and immunology of tuberculosis. The current epidemiological situation and disease control are then discussed. Attention is drawn to the importance of using high-grade standardized forms of tuberculin. The complicated nature of the chemical formula and immunological characteristics of tuberculin, including modern forms of PPD tuberculin, are commented upon, and the paper is concluded with a look into the future regarding modern diagnostic prospects such as the development of synthetically manufactured tuberculin, the use of specific monoclonal antibodies and specific DNA probes.

[Type-C botulism in dogs]

Twelve dogs died from an outbreak of type-C botulism. The origin of the outbreak was found to consist in feeding the dogs broiler carcasses contaminated with Clostridium botulinum type-C. High concentrations of toxin type-C could be detected in the stomach contents. Botulism in dogs was only fatal when large amounts of toxin had been produced.

The efficacy of mesenteric lymph node biopsy in the eradication of paratuberculosis from an infected dairy farm

Lymph node biopsy was performed on animals older than nine months on a dairy farm which carried 223 animals and was severely affected by paratuberculosis. Biopsies were examined histologically and bacteriologically for the presence of M. paratuberculosis infection. In this way paratuberculosis infection was diagnosed in 29 animals, in which other diagnostic methods (serum complement fixation test, intradermal johnin test and microscopic examination of the faeces) produced negative results. The value of lymph node biopsy is the early detection of infected animals. In the two years after the biopsies, no further cases of clinical paratuberculosis were detected on the affected farm, although infection with M. paratuberculosis persisted.

The potency of bovine PPD tuberculins in guinea-pigs and in tuberculous cattle

Potency differences between bovine purified protein derivative tuberculin preparations produced in two different centres and also between preparations produced within these centres, were detected in tuberculous cattle and correlated with potency differences in guinea-pigs. Although assays in groups of guinea-pigs sensitized with either killed Mycobacterium bovis or live BCG identified the weak batches and listed the tuberculins in the same order of potency as the cattle assays, there were nevertheless significant differences between potency estimates according to the mode of sensitization and the preparations compared. The implications for the standardization of tuberculin preparation in general are discussed.