Post-mortem Inspection Research Articles

도축 소에 있어서 육안적 검사 방법에 따른 간질 감염 실태조사

This study was conducted to investigate the prevalence of fascioliasis in slaughtered cattle in Kangwon (Wonju, Hoengseong, Hongcheon, Cheorwon, Pyeongchang) province and Daejeon from October to December in 2014. From the total 10,780 examined cattle, 0.54% (58/10,780) were found to be positive for fascioliasis by postmortem macroscopic inspection. The Fasciola spp. infection rates were higher in the most Daejeon (1.83%, 41/2,240), followed by Hoengseong (0.40%, 15/3,714) and Hongcheon (0.22%, 2/901). It was not infected in the other regions. The outward appearances of Fasciola spp. infected livers looked almost normal and the worms were all parasitize in the main hepatic duct.

Small – but fatal: Postmortem computed tomography indicated acute tonsillitis

Abstract The objective of this case report was to highlight the benefit of postmortem imaging in the detection of focus of infection and inflammation in minor accessible neck regions. However the cooperation of postmortem imaging, external inspection and autopsy was constructive. Forensic imaging included a routine whole-body postmortem computed tomography (PMCT) using a dual-source CT scanner (Flash Definition, Siemens, Forchheim, Germany). Initial external inspection and subsequent autopsy were performed. The imaging results revealed focused emphysema of the neck descending to the mediastinum. External inspection showed unusual, cervical greenish discoloration; the autopsy exposed swollen palatine tonsils; and acute, purulent tonsillitis was the focus of infection. Ultimately an acute heart failure due to a septic shock resulted. Postmortem imaging supports medico-legal investigation with external inspection and autopsy in detecting the focus of infection in the palatine tonsils and in challengingly reachable anatomic areas such as neck regions. Literature recommends computed tomography with contrast media and magnetic resonance imaging for the detailed visualization of this body region for the living. According to our experience, we support this recommendation also for the deceased.

Qualité de la viande de dromadaire dans les abattoirs de Ouargla en Algérie. II. Contamination bactérienne superficielle des carcasses

Dans le but d’apprécier la qualité microbiologique de la viande de dromadaire produite à l’abattoir de la wilaya de Ouargla en Algérie, la contamination superficielle d’origine bactérienne de 60 carcasses camelines a été évaluée. Les prélèvements ont été réalisés par écouvillonnage de trois sites (cuisse, flanc et épaule). Les échantillons ont été prélevés dans un intervalle d’une heure après l’abattage de l’animal, après le dépouillement, à la fin de l’éviscération et avant l’inspection post mortem. Les taux de germes ont varié en fonction des carcasses et des sites de prélèvement. La flore prédominante a été la flore aérobie mésophile totale, dont le niveau de contamination a été de 2,8 log UFC/cm2, représentant 25 p. 100 de la flore dénombrée, suivie par les entérobactéries avec 2,4 log UFC/cm2 (21 p. 100), les coliformes totaux avec 2,2 log UFC/cm2 (20 p. 100), les coliformes fécaux avec 2,0 log UFC/ cm2 (18 p. 100), et les staphylocoques avec 1,8 log UFC/cm2 (16 p. 100). La présence de souches de salmonelles et d’Escherichia coli a été détectée sur toutes les zones prélevées de la carcasse. La viande cameline de l’abattoir de Ouargla a présenté un niveau de contamination élevé par les germes pathogènes (salmonelles et staphylocoques). Une contamination fécale (E. coli) élevée a également été observée. De bonnes pratiques d’hygiène durant la phase d’abattage doivent être mises en œuvre afin de diminuer le niveau de contamination.

A survey on the efficacy of tulathromycin in the treatment of infectious pneumonia of small ruminants in Iran

The principle aims of this study were to evaluate clinical, hematological, microbiological and macro and micro pathological effects of tulathromycin on small ruminants infectious pneumonia (IP) and to determine the side effects of the drug in the injected site. For this purpose, all ruminants (10 sheep and 9 goats) with signs of IP were assembled in the Khorasan-E-Razavi Province Veterinary Organization research centre. Also, all of these animals were free of internal parasite infestations and free of hydrated cysts in the lung tissue. Before tularthromycin injection, samples were taken as nasopharyngeal swabs for culturing Pasteurella spp. and Mycoplasma spp. and performing the Cell Blood Count (CBC) for blood. Each animal was injected at the dose of 2.5 mg/Kg subcutaneously. In 24-, 48- and 72-hours after injection, body temperature (BT), respiratory rate (RR), heart rate (HR), ruminal contraction rate (RCR), lung sounds (LS) and nasal discharges (ND) were recorded between 9-12 pm. Meanwhile on day 1 and day 3, the blood sampling was repeated and on day 3 nasopharyngeal swabs were repeated. Furthermore, 9 sheep and goats were killed on day 9 and the remainders were killed on the day 15 following injection and post-mortem inspections were conducted on lungs. From cases with lung lesions, a sample was taken for histopathological examination. The data showed that: A) The mean difference of BT, RR and HR of 0-, 24-, 48-, and 72-hrs after Tulathromycin injection was significantly different (p< 0.05). B) The mean difference of No. WBC and % neutrophils of 0-, 24-, 48-, 72-hrs was significant (p< 0.05). C) Pasteurella spp. was isolated from all sheep and goats before injection while this organism was cultured in only 2 of the animals on day 3 after tulathromycin injection (p< 0.05). D) Mycoplasma spp. was cultured from 57.9% of the small ruminants and the results were identical in the second culturing with the exception of one animal. Mycoplasma spp. was cultured from 57.9% of the small ruminants and the results were identical in the second culturing with the exception of one animal. E) 50% and 44.4% of the sheep and goats that were killed on the 9th and 15th days post-injection showed various pulmonary lesions including apical lob consolidation, apical lob consolidation plus adhesion, bronchopneumonia plus observed pleurisy. On the basis of this investigation Tulathromycin has not had any antibacterial effect on Mycoplasma spp.

Determination of Corynebacterium pseudotuberculosis prevalence and antimicrobial susceptibility pattern of isolates from lymph nodes of sheep and goats at an organic export abattoir, Modjo, Ethiopia.

Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis, a suppurative abscessation in the superficial and internal lymph nodes and internal organs of small ruminants. This study was conducted on the superficial lymph nodes and carcasses of 768 small ruminants slaughtered at a slaughterhouse during the study period; 82 had abscesses or caseous lymphadenitis. The most frequent sites of abscesses in goats were the prescapular (34, 5·54%) and prefemoral lymph nodes (24, 3·91%) respectively. Similar patterns were observed in sheep. The prevalence of caseous lymphadenitis was found to be significantly higher in adult than in young animals, in both species (P < 0·05). The age-wise prevalence rates of lesions on post-mortem inspection, at 95% CI, were 2·7% (2·3-3·1%) and 3·1% (2·8-3·4%) in young sheep and goats, respectively, and 24·4% (17·4-31·4%) and 27·5% (23·8-31·2%) in adult sheep and goats respectively. Corynebacterium pseudotuberculosis isolates were recovered from 72% (59/82) of animals found to have post-mortem evidence of abscesses. The Coryne. pseudotuberculosis isolates were susceptible to the antibiotics norfloxacin, tetracycline, doxycyline HCl and kanamycine; however, resistance was observed against ampicillin, clindamycin and doxycyline HCl. In conclusion, this study reported the magnitude of the problem in the country for the first time and the authors recommend a thorough investigation of wider study areas. This work presents data on the prevalence of caseous lymphadenitis in slaughtered sheep and goats as well as the isolation and antibiotic susceptibility pattern of Corynebacterium pseudotuberculosis for the first time in Ethiopia. The carcasses of small ruminants are the major livestock product exported from the country and serves as an important source of foreign currency. Assessing the impact of diseases such as caseous lymphadenitis in the industry would be of great significance. This work forms initial data that call for further wider investigations to gain complete understanding of its impact in the country.

When is a post-mortem skeletal survey of the fetus indicated, and when not?

Objective: Radiography after fetal or perinatal death has become a routine part of post-mortem diagnostics. However, only a selected subset of these babygrams or fetal post-mortem skeletal surveys (FPSSs) provides useful information. We investigated the indication for a FPSS.Methods: Inclusion consisted of the routinely made FPSS (2002–2012) in our university hospital in cases of fetal or perinatal death up to 7 days after birth. We categorized the diagnostic value of the FPSS as no, minor, major or pathognomonic. Regression analysis was used to determine the selection criteria for a useful FPSS.Results: Three hundred and thirty-seven FPSS were included. Three hundred and five (91%) FPSS showed no or minor skeletal malformations. Fourteen (4.2%) FPSS had major skeletal malformations. In 18 (5.3%) cases the diagnosis was based on the pathognomonic skeletal malformations on the FPSS. Two cases were false positive after major birth trauma. The presence of multiple skeletal malformations on prenatal ultrasound or at post-mortem external inspection was highly indicative of a diagnostic FPSS (p < 0.001).Conclusion: The majority of the babygrams/FPSS has no contribution to the diagnostic process. Multiple skeletal malformations on prenatal ultrasound or post-mortem external inspection are indicative for a diagnostic FPSS, and this should be the main selection criterion.

DVM Dx

"True knowledge lies at the dead pile." First heard from Dr. Eugene Janzen, but likely quoted many times by cattle veterinarians! The digital revolution provides new tools with the potential to change how necropsies are conducted; however, these tools' validity must be tested. As a project of Merck Animal Health, a mobile and web-based application was designed to systematically collect digital necropsy images, making them available to diagnosticians. DVMDx is based on proprietary digital and web-based diagnostic systems used for 20 years by Feedlot Health Management Services Ltd. To validate this system, trained veterinary students followed a prescribed digital necropsy protocol on 192 cattle from feedlots and calf ranches with clinical respiratory disease. In parallel, tissues samples were submitted to a diagnostic laboratory for histopathological and microbiological evaluation. Veterinarians experienced in interpreting digital images provided a single "most likely” syndromic diagnosis which was compared to laboratory and microscopic findings. An antemortem diagnosis of respiratory disease was confirmed by gross image analysis in 90%, and by laboratory testing in 94%, of the cases. Digital and laboratory diagnoses agreed in 79% of the cases when the primary diagnoses were compared, and 88% when all diagnoses were compared. When the syndromic diagnosis predicted the etiology based on digital images, Histophilus somni and Mycoplasma bovis were confirmed in 25% and 100% of the cases, respectively. These data support the further refinement of this tool, which has the potential to significantly increase the number of animals receiving cost-effective and diagnostic postmortem inspections.

Determination of anthelmintic efficacy against Toxocara canis in dogs by use of capsule endoscopy

Industry guidelines for anthelmintic testing call for postmortem inspection of animals to verify treatment efficacy. A previous study showed that capsule endoscopy (CE) can be performed on dogs in vivo to quantify hookworms in the small intestine. Adoption of a minimally invasive procedure such as this could reduce the need for necropsy in efficacy trials. The present study employed CE to enumerate Toxocara canis in dogs, with two main goals: to determine if multiple capsule examinations improves the accuracy of worm counts compared to a single examination, and to establish if the efficacy of an anthelmintic compound is the same whether calculated using CE or necropsy data. To avoid needless animal sacrifice, the study was carried out on beagle dogs already in a product development trial with a planned terminal endpoint. Dogs were infected by oral inoculation with T. canis eggs. Untreated control dogs (n=8) were evaluated by CE three times while dogs treated with test compounds (3 groups of 4) were examined only once. Utilizing either the average count or just the last complete capsule examination, a robust correlation was found between CE and postmortem numbers (r=0.94, p<0.001). Calculated anthelmintic efficacy was essentially identical for the two enumeration methods, ranging from 94% to 100% for the three research compounds. CE may therefore be a viable alternative to necropsy for T. canis parasiticide trials.

Echinococcus granulosus: Epidemiology and state-of-the-art of diagnostics in animals

Diagnosis and detection of Echinococcus granulosus (sensu lato) infection in animals is a prerequisite for epidemiological studies and surveillance of echinococcosis in endemic, re-emergent or emergent transmission zones. Advances in diagnostic approaches for definitive hosts and livestock, however, have not progressed equally over the last 20 years. Development of laboratory based diagnostics for canids using coproantigen ELISA and also coproPCR, have had a huge impact on epidemiological studies and more recently on surveillance during hydatid control programmes. In contrast, diagnosis of cystic echinococcosis (CE) in livestock still relies largely on conventional post-mortem inspection, despite a relatively low diagnostic sensitivity especially in early infections, as current serodiagnostics do not provide a sufficiently specific and sensitive practical pre-mortem alternative. As a result, testing of dog faecal samples by coproantigen ELISA, often combined with mass ultrasound screening programmes for human CE, has been the preferred approach for monitoring and surveillance in resource-poor endemic areas and during control schemes. In this article we review the current options and approaches for diagnosis of E. granulosus infection in definitive and animal intermediate hosts (including applications in non-domesticated species) and make conclusions and recommendations for further improvements in diagnosis for use in epidemiological studies and surveillance schemes.

Toxoplasma gondii in wild ruminants bred in game preserves and farms with production destined for human consumption in the Czech Republic.

Toxoplasma gondii is the causative agent of the most common parasitic infection in humans. Almost all warm-blooded animals, as well as humans, can act as intermediate hosts that harbour infective cysts in their tissues. Felids act as definitive hosts excreting oocysts in faeces. In humans, T. gondii can cause subclinical infection but also severe clinical disease with a wide range of symptoms, especially in immunocompromised individuals. The infection is usually asymptomatic in animals and is not recognized at either ante- or post-mortem inspection. The consumption of undercooked meat from infected animals is one of the most important routes by which the infection can be transmitted to humans. Handling of the organs and other tissues of game animals and eating their undercooked meat have been described as a risk of T. gondii infection. For diagnosis of toxoplasmosis, the combination of serological and molecular methods has been described as a suitable approach. Antibodies against T. gondii were detected in 20.8%, 50.0%, 23.1%, and 24.4% of red deer, sika deer, fallow deer and mouflons, respectively, coming from game preserves and farms in the Czech Republic. T. gondii DNA was found in the muscle tissue of red deer (8.3%) and mouflons (14.6%). The lower prevalence rates based on molecular screening could be due to the random distribution and low density of cysts in tissues of infected animals. Bearing in mind the increase in the number of hunted animals and the growing trend in game consumption, it is important to educate hunters and game meat consumers about the risk of exposure to this zoonotic infection during handling and consumption of the meat.

Applicability of ELISA with different antigens to diagnose varying levels bovine cysticercosis

Ensaios foram conduzidos para avaliar a eficiência de antígenos de larva de Taenia crassiceps (Tcra) no teste ELISA para o diagnóstico da cisticercose bovina. Três antígenos foram avaliados: total (T), total sonicado (Ts) e de membrana (M). As amostras analisadas foram soros-controle positivos e negativos para a cisticercose, além de soros de bovinos com outras patologias. As taxas de sensibilidade para o teste ELISA foram respectivamente, com 2 e 3 desvios-padrão, 85,0 e 81,25% para o antígeno T, 82,5 e 78,75% para o antígeno Ts e 80,0 e 80,0% para o antígeno M; as taxas de especificidade, com 2 e 3 desvios-padrão, foram respectivamente: 47,5 e 58,75% para o antígeno T, 65,0 e 73,75% para o antígeno Ts e 58,75 e 62,5% para o antígeno M. Estes resultados demonstram que o ELISA, apesar de apresentar melhor desempenho em detectar animais experimentalmente infectados, apresentou taxa de sensibilidade superior ao exame anatomopatológico realizado durante a rotina de inspeção relatada por outros estudos. No entanto, o exame post mortem é superior quanto a especificidade, uma vez que é considerado altamente específico. Assim, a combinação de ambas as técnicas diagnósticas deve ser valorizada na detecção da cisticercose bovina, demonstrando a aplicabilidade prática do ELISA.

CORRUZIONE E MALATTIA NELLA MEDICINA D’ETÀ MODERNA

The concept of corruption plays a central role in early modern medicine, in which it can refer either to the disease process or to the decaying process that follows the death of the body. The article explores these different meanings of the term, and their relative tensions, in two specific areas: medicina practica and anatomy. While in practical medicine the concept of corruption is generally associated to the process of putrefaction that accompanies the disease, in anatomy the question arises whether the corruption of the body, observed during post-mortem inspection, precedes or follows the death of the patient. The different uses of the concept of corruption show the ambiguity of this term in early modern medicine, but also its ubiquitous presence and important role in the medical discourse and practice.

A simulation study on the statistical monitoring of condemnation rates from slaughterhouses for syndromic surveillance: an evaluation based on Swiss data.

Syndromic surveillance (SyS) systems currently exploit various sources of health-related data, most of which are collected for purposes other than surveillance (e.g. economic). Several European SyS systems use data collected during meat inspection for syndromic surveillance of animal health, as some diseases may be more easily detected post-mortem than at their point of origin or during the ante-mortem inspection upon arrival at the slaughterhouse. In this paper we use simulation to evaluate the performance of a quasi-Poisson regression (also known as an improved Farrington) algorithm for the detection of disease outbreaks during post-mortem inspection of slaughtered animals. When parameterizing the algorithm based on the retrospective analyses of 6 years of historic data, the probability of detection was satisfactory for large (range 83-445 cases) outbreaks but poor for small (range 20-177 cases) outbreaks. Varying the amount of historical data used to fit the algorithm can help increasing the probability of detection for small outbreaks. However, while the use of a 0·975 quantile generated a low false-positive rate, in most cases, more than 50% of outbreak cases had already occurred at the time of detection. High variance observed in the whole carcass condemnations time-series, and lack of flexibility in terms of the temporal distribution of simulated outbreaks resulting from low reporting frequency (monthly), constitute major challenges for early detection of outbreaks in the livestock population based on meat inspection data. Reporting frequency should be increased in the future to improve timeliness of the SyS system while increased sensitivity may be achieved by integrating meat inspection data into a multivariate system simultaneously evaluating multiple sources of data on livestock health.

Serological Follow-up of Tuberculosis in a Wild Boar Population in Contact with Infected Cattle.

There is an increasing concern in several European countries over the role that tuberculosis (TB)-infected wild boar may play in the progress of bovine TB eradication campaigns. In 2004, as a consequence of the detection of a TB focus in wild boar from a National Game Reserve (NGR) located in southern Catalonia, a surveillance programme based on post-mortem inspection for detection of macroscopic TB-like lesions (TBLL) was initiated in the affected area. The source of infection for wild boar was linked to a tuberculous cattle herd located in the same area. Besides, the results of the surveillance programme in wild boar were used for the validation of an indirect enzyme-linked immunosorbent assay (ELISA) specific for Mycobacterium tuberculosis complex (MTBC) IgG antibodies. Using this ELISA, a seven-year serological study of MTBC in wild boar from the NGR was conducted in 173 animals (93 adults, 44 juveniles-yearlings and 36 piglets) culled between 2004 and 2010. ELISA results and presence of TBLL showed excellent agreement for adult and juvenile wild boar (Kappa index=0.85; 95% CI: 0.76-0.95). Of the thirty-eight adults, yearlings and juveniles classified as positives by the ELISA, 34 (89%) showed TBLL at necropsy. In contrast, none of the ELISA-positive wild boar piglets (n=20) showed TBLL, suggesting the detection of early antibody responses to the infection. Overall, this study contributes to the knowledge of wild boar humoral responses to MTBC. The results also highlight the usefulness of this serological test for wild boar TB surveillance.

Nonlinear Aging of Lithium-Ion Cells Linked to Pressure Differences: Degradation Mechanisms and Remedies

Lithium-ion batteries have great potential in electromobility and stationary applications. Reusing aged batteries from cars in 2nd-life-applications could lower cost and ecological impact. For such usage scenarios, information on the expected remaining lifetime at takeover is critical. Current aging studies focus mostly on the aging behavior above 80 % residual capacity. Nonetheless, some studies report on an abrupt acceleration of the aging rate upon prolonged testing [1-4]. These results may challenge second life scenarios due to the aggravated predictability of the aging trends. A comprehensive aging experiment was performed on commercial NMC//graphite based 18650 cells to identify conditions leading to such a default. Pronounced nonlinear aging behavior could be reproduced in the laboratory for cells cycled with a high depth of discharge (Fig. 1). Post-mortem investigations reveal localized aging mechanisms as the reason for nonlinear aging trends. In this publication, nonlinear aging behavior is linked to inhomogeneous aging phenomena in graphite based cells. Patterns of lithium plating, the migration of cathodic oxidation products and pronounced lithium loss are observed in affected cells (Fig. 2). Localized lithium depletion appears to be the origin of an abrupt decline of the whole cell’s performance. Klett et al. found similar plating patterns in LiFePO4//graphite based cells and stated that differences in temperature, pressure or electrode quality may be the cause for this behavior [4]. By using thermography, micro computed tomography, scanning electron microscopy and a variety of electrochemical measuring techniques, the aging mechanisms responsible for pronounced aging could clearly be linked to pressure differences, while temperature gradients could be ruled out. The impact of pressure is confirmed by applying controlled, localized stress and electrochemical control experiments. Based upon a comprehensive aging experiment and extensive post-mortem investigations, underlying causes for pronounced nonlinear aging near automotive end-of-life are clarified. A clear cause-and-effect chain from pressure differences to plating is established. The aging mechanisms leading to localized degradation in a lithium-ion cell are described qualitatively. It is confirmed that avoiding extreme anode potentials effectively reduces the risk of pronounced aging in carbon based lithium-ion cells. The necessary limits depend on anode composition and cell design. Based upon the presented findings, different cell designs can be evaluated by a combination of cyclic aging and visual post-mortem inspection. References M. Ecker, N. Nieto, S. Käbitz, J. Schmalstieg, H. Blanke, A. Warnecke and D. U. Sauer, Journal of Power Sources, 248, 839–851 (2014).Z. Guo, X. Qiu, G. Hou, B. Y. Liaw and C. Zhang, Journal of Power Sources, 249, 457–462 (2014).D. A. Stevens, R. Y. Ying, R. Fathi, J. N. Reimers, J. E. Harlow and J. R. Dahn, Journal of the Electrochemical Society, 161(9), A1364 (2014).M. Klett, R. Eriksson, J. GROOT, P. Svens, K. Ciosek Högström, R. W. Lindström, H. Berg, T. Gustafson, G. Lindbergh and K. Edström, Journal of Power Sources, 257, 126–137 (2014). Figure 1

Successful serial imaging of the mouse cerebral arteries using conventional 3-T magnetic resonance imaging.

Serial imaging studies can be useful in characterizing the pathologic and physiologic remodeling of cerebral arteries in various mouse models. We tested the feasibility of using a readily available, conventional 3-T magnetic resonance imaging (MRI) to serially image cerebrovascular remodeling in mice. We utilized a mouse model of intracranial aneurysm as a mouse model of the dynamic, pathologic remodeling of cerebral arteries. Aneurysms were induced by hypertension and a single elastase injection into the cerebrospinal fluid. For the mouse cerebrovascular imaging, we used a conventional 3-T MRI system and a 40-mm saddle coil. We used non-enhanced magnetic resonance angiography (MRA) to detect intracranial aneurysm formation and T2-weighted imaging to detect aneurysmal subarachnoid hemorrhage. A serial MRI was conducted every 2 to 3 days. MRI detection of aneurysm formation and subarachnoid hemorrhage was compared against the postmortem inspection of the brain that was perfused with dye. The imaging times for the MRA and T2-weighted imaging were 3.7±0.5 minutes and 4.8±0.0 minutes, respectively. All aneurysms and subarachnoid hemorrhages were correctly identified by two masked observers on MRI. This MRI-based serial imaging technique was useful in detecting intracranial aneurysm formation and subarachnoid hemorrhage in mice.

Degradation of Anion Exchange Membranes (AEM) and Solubilized AEM Binders in Solid-State Alkaline Water Electrolyzers

Hydrogen production using alkaline membrane water electrolysis has recently attracted interest as an alternative to traditional liquid alkaline water electrolysis, proton exchange membrane water electrolysis, and solid-oxide water electrolysis (1). Alkaline membrane electrolyzers provide an efficient, modular, and reliable method to produce hydrogen from water and renewable electricity sources. One advantage arises from the fact that the alkaline environment facilitates better oxygen evolution reaction (OER) kinetics and allows the use of non-platinum group catalysts for the OER (2) (Of course, one must acknowledge that this is countered by the more sluggish HER in alkaline media). In a solid-state alkaline membrane water electrolyzer, the anion exchange membrane (AEM) has two functions: 1) it acts as an impermeable barrier to the fuel and oxidant gases; and 2) conducts the hydroxide ions from the cathode, where they are generated by the electrochemical reduction of oxygen, to the anode. In this work we will discuss our latest findings on AEM degradation under alkaline conditions encountered during AEM water electrolyzer operation. Despite the promising results reported in terms of hydroxide ion conductivities and electrolyzer performance, there is a general understanding that the AEM membranes and solubilized AEM binders do not yet have the necessary alkaline stability for practical applications. It is accepted that the mechanisms of AEM degradation under alkaline conditions are related to the common and well-reported modes under which the fixed cation groups degrade. Quaternary ammonium groups can degrade under alkaline conditions through: 1) Hoffman elimination, where the quaternary cation is cleaved, leaving as tertiary amine, and resulting in the formation of an alkene at the carbon where the ammonium was bonded (requires the presence of alpha and beta hydrogen); 2) a direct nucleophilic reaction where the cation is completely cleaved, resulting in the formation of a tertiary amine and an alcohol at the carbon where the ammonium was bonded to the polymer backbone; and 3) through another nucleophilic substitution reaction where the adjacent organic moiety to the inorganic atom (usually a methyl or alkyl group) is cleaved resulting in the formation of a tertiary amine and an alcohol. There are other less frequently observed degradation pathways, that involve the formation of ylide intermediates, known as Sommelet–Hauser and Stevens rearrangements. All these mechanisms involve the presence of a strong base and cause the formation of tertiary amines with the subsequent loss of ion exchange capacity and ionic conductivity. However, cation degradation alone cannot account for all the membrane deterioration encountered during AMFCs operation. It has been observed that the AEM membranes and solubilized AEM binders suffer degradation that affects the integrity of the polymer backbone. Postmortem inspection of the MEAs and probing via 1D and 2D NMR spectroscopy confirmed backbone hydrolysis. The degradation is especially intense in the anode side of the electrolyzer. In an experiment with two AEM separators placed together, we observed preferential thinning of the membrane in contact with the anode. We also investigated the prevailing hypothesis that the backbone hydrolysis was triggered by the presence of quaternary ammonium cations in close proximity to the aromatic rings (ether hydrolysis leading to chain scission) (3). We evaluated the alkaline stability of AEMs with six carbon pendant chains tethered to the polyphenylene backbone and derivatized with trimethylamine (TMA) and quinuclidine (ABCO). We found that such AEMs underwent chemical degradation under alkaline conditions yielding similar products encountered in AEMs without pendant chains. In an attempt to explain the preferential degradation and thinning of the membrane at the anode of an operating electrolyzer, we studied the effect of oxygen on AEM degradation in alkali. We compared the AEM degradation of PPO-based AEMs in oxygen-saturated 1M KOH and nitrogen-degassed 1M KOH. The presence of oxygen accelerated the degradation of the AEMs. It was found that the PPO-TMA membranes lost 50% of their ion exchange capacity after 30 days immersed in oxygen-saturated 1M KOH (at 60°C). When the membranes were kept in nitrogen-degassed 1M KOH they only lost 20% of their IEC under similar conditions. This is clear evidence that oxygen, and probably reactive oxygen species (superoxide), are actively involved in the alkaline degradation of the PPO-TMA+ AEMs. NMR spectra of degraded AEMs as well as other evidence of preferential degradation in the presence of oxygen will be presented and discussed.

Evaluation of the efficiency of nested q-PCR in the detection of Mycobacterium tuberculosis complex directly from tuberculosis-suspected lesions in post-mortem macroscopic inspections of bovine carcasses slaughtered in the state of Mato Grosso, Brazil

Bovine tuberculosis (BTB) is a zoonotic disease caused by Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex (MTC). The quick and specific detection of this species is of extreme importance, since BTB may cause economic impacts, in addition to presenting imminent risks to human health. In the present study a nested real-time PCR test (nested q-PCR) was used in post-mortem evaluations to assess cattle carcasses with BTB-suspected lesions. A total of 41,193 cattle slaughtered in slaughterhouses located in the state of Mato Grosso, were examined. Of the examined animals, 198 (0.48%) showed BTB-suspected lesions. M. bovis was isolated in 1.5% (3/198) of the samples. Multiplex-PCR detected MTC in 7% (14/198) of the samples. The nested q-PCR test detected MTC in 28% (56/198) of the BTB-suspected lesions, demonstrating higher efficiency when compared to the multiplex-PCR and conventional microbiology. Nested q-PCR can therefore be used as a complementary test in the national program for control and eradication of bovine tuberculosis.

Prevalence of Taenia saginata Larvae (Cysticercus bovis) in Feedlot Cattle Slaughtered in a Federal Inspection Type Abattoir in Northwest México.

The prevalence of bovine cysticercosis was established using routine postmortem inspection of 52,322 feedlot cattle slaughtered at 1 Federal Inspection Type abattoir (TIF 301) located in the Mexicali Valley in Baja California, México. The study included 31,393 animals (60.0%) purchased and transported to Baja California from stocker operations located in 17 states of México and 20,929 animals (40.0%) native to Baja California. A total of 208 carcasses showed lesions suggestive of cysticercosis, and 109 were confirmed as positive for the parasite with a prevalence of 0.21%, equivalent to 2.1 cases/1000 carcasses inspected, 2.8 cases/1000 carcasses for cattle purchased in other states, and 1.0 cases/1000 carcasses for cattle native from Baja California. The sensitivity of the postmortem inspection, when compared to a gold standard of stereoscopic microscopy, was 52.4%. The prevalence of cysticercosis was 2.8 times higher in cattle from other states compared with those native to Baja California. Cysticerci were most frequently found in the heart, followed by liver and masseter muscles. In cattle from other states, 96.6% of cysticerci were classified as calcified and <4% as viable; in cattle native to Baja California, 29% of cysticerci were classified as calcified and 71% as viable. The prevalence of bovine cysticercosis established at TIF 301 was found to be 28% lower than a previous report for Baja California. However, given the sensitivity of the postmortem inspection calculated between 10% and 50%, it is possible that an undetermined number of carcasses pass as being free of cysticerci and that the meat reached both domestic and international wholesale markets, increasing the possibility of human infection and causing substantial economic loss through condemnation of infected meat and trade restrictions for endemic regions.

Epidemiological modelling for the assessment of bovine tuberculosis surveillance in the dairy farm network in Emilia-Romagna (Italy)

Assessing the performance of a surveillance system for infectious diseases of domestic animals is a challenging task for health authorities. Therefore, it is important to assess what strategy is the most effective in identifying the onset of an epidemic and in minimizing the number of infected farms.The aim of the present work was to evaluate the performance of the bovine tuberculosis (bTB) surveillance system in the network of dairy farms in the Emilia-Romagna (ER) Region, Italy. A bTB-free Region since 2007, ER implements an integrated surveillance strategy based on three components, namely routine on-farm tuberculin skin-testing performed every 3 years, tuberculin skin-testing of cattle exchanged between farms, and post-mortem inspection at slaughterhouses. We assessed the effectiveness of surveillance by means of a stochastic network model of both within-farm and between-farm bTB dynamics calibrated on data available for ER dairy farms. Epidemic dynamics were simulated for five scenarios: the current ER surveillance system, a no surveillance scenario that we used as the benchmark to characterize epidemic dynamics, three additional scenarios in which one of the surveillance components was removed at a time so as to outline its significance in detecting the infection. For each scenario we ran Monte Carlo simulations of bTB epidemics following the random introduction of an infected individual in the network. System performances were assessed through the comparative analysis of a number of statistics, including the time required for epidemic detection and the total number of infected farms during the epidemic.Our analysis showed that slaughterhouse inspection is the most effective surveillance component in reducing the time for disease detection, while routine surveillance in reducing the number of multi-farms epidemics. On the other hand, testing exchanged cattle improved the performance of the surveillance system only marginally.