Modelling the spread of foot-and-mouth disease virus

Foot-and-mouth disease is an economically important viral disease in animals. It is shown that airborne diffusion is one of the main sources of contamination between animals and between herds. Epidemiological data linked to viral particle excretion can thus be used in a predictive model, added to meteorological data related to the few days before the slaughter of animals. The model computes, on a 10 km radius around the outbreak and in every space direction, the quantity of viral particles that a sensitive animal could have breathed. The aim is to define a risk area, and, according to the number and size of farms in the surrounding, to give arguments for the best sanitary decision within the emergency plan.     

Simulated airborne spread of Aujeszky's disease and foot-and-mouth disease

The atmospheric dispersion of virus was simulated using a computer model which had been developed for predicting the dispersion of toxic gases from chemical engineering plants. The results were compared with data from four outbreaks in which virus was believed to have been transported by air: two outbreaks of foot-and-mouth disease in the United Kingdom in 1967 and outbreaks of Aujeszky's disease in Yorkshire in 1981 to 1982 and Indiana in 1988. There was relatively good agreement with most of these data. The paper shows that the model could be useful in an emergency because the risk of virus spread could be predicted in real time.     

Risk indicators for inflammatory bowel disease

We investigated the association between different risk indicators and inflammatory bowel disease in a case-control study based on the population of Stockholm County during 1980-1984. Information on physical activity, oral contraceptives, some previous diseases and childhood characteristics was collected using a postal questionnaire for 152 cases of Crohn's disease, 145 cases of ulcerative colitis, and 305 controls. The relative risk (RR) of Crohn's disease was inversely related to regular physical activity and estimated at 0.6 (95% CI: 0.4-0.9) and 0.5 (95% CI: 0.3-0.9) for weekly and daily exercise, respectively. Having psoriasis prior to the inflammatory bowel disease was associated with an increased relative risk of Crohn's disease (RR = 2.9, 95% CI: 1.1-7.9). Use of oral contraceptives was associated with an increased RR of 1.7 for both Crohn's disease and ulcerative colitis. Crohn's disease confined to the colon and total ulcerative colitis at diagnosis were most strongly associated with oral contraceptives.     

旋流燃烧器特性评价指标的研究

用数值模拟的方法,以鼓风式空气旋流燃烧器为例,模拟了不同操作参数和结构参数下炉膛内的温度场、速度场和污染物浓度场,提出了评价旋流燃烧器的几种特性指标,对旋流燃烧器进行较全面的特性评价。     

Premorbid psychometric indicators of the gene for Huntington's disease.

Follow-up was made of 88 Ss who had a 50% chance of inheriting Huntington's disease (HD) from a parent and who had been tested 15–20 yrs previously. Striking differences were seen in premorbid mean test scores (Shipley-Institute of Living Scale for Measuring Intellectual Impairment, Bender Visual Motor Gestalt Test, and the Wechsler intelligence tests) between 28 Ss who developed HD and 60 Ss who remained free of HD symptoms. The overall pattern of mean test scores showed progressively lower scores with increased closeness to overt HD. Attempts at "prediction" with test scores were made. Although hit–miss ratios as high as 3 to 1 were found with the intellectual tests, cross-validation could drastically reduce the high prediction accuracy. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Northern bobwhites as disease indicators for the endangered Attwater''s prairie chicken

Gabapentin is an anticonvulsant that may represent a novel class of drugs, which has novel spinal antihyperalgesic activity. We sought to characterize this spinal action in a model of hyperalgesia that involves a mild thermal injury to the hind paw of the rat. Rats were prepared with chronic spinal catheters. Under brief halothane anesthesia, a thermal injury was induced by applying the left hind paw to a thermal surface (52.5 degrees C) for 45 s. This exposure results in mild erythema but no blistering. Thermal escape latency of the hind paw was determined using an underglass thermal stimulus with which response latencies of the injured and uninjured (normal) paw could be obtained. Thirty minutes after thermal injury, the response latency in all groups decreased from 10-12 s to 5-7 s. Uninjured paw withdrawal latency was unaltered. The intrathecal injection of gabapentin (30-300 microg) produced a dose-dependent reversal of the hyperalgesia but had no effect on the response latency of the normal hind paw, even at the largest doses. A similar reversal was observed after intrathecal delivery of the structural analog S(+)-3-isobutyl gamma-aminobutyric acid (GABA) (30-300 microg), but not after the largest dose of its stereoisomer R(-)-3-isobutyl GABA (300 microg). The effects of both intrathecal gabapentin and S(+)-3-isobutyl GABA were reversed by intrathecal D-serine, but not L-serine. All effects were observed at doses that had no significant effect on motor function. These observations, in conjunction with the accumulating data on binding and transmitter release, emphasize that these gabapentinoids can selectively modulate the facilitation of spinal nociceptive processing otherwise generated by persistent small afferent input generated by tissue injury. Implications: Gabapentin and its analog, 3-isobutyl gamma-aminobutyric acid, given spinally, produce a dose-dependent, D-serine-sensitive reversal of the thermal hyperalgesia evoked by mild thermal injury.     

Application of double sandwich enzyme-linked immunosorbent assay for the diagnosis of foot-and-mouth disease in Saudi Arabia

A case of Hemangiopericytoma at the thigh is reported. The Hemangiopericytoma is a rare tumour made with pericyties. This neoplasia is usually benign and it is located in the soft tissues. Tumour is profusely irrigated. The most common locations of the Hemangiopericytoma are the lower limbs and the abdominal cavity. The Hemangiopericytoma is difficult to be recognized by histological criteria. The high number of relapses and metastasis involve to an extent surgical ablation of the tumour and its borders. Present literature is reviewed and the different diagnostic and therapeutic options are discussed.     

Pathogenesis of wild-type and leaderless foot-and-mouth disease virus in cattle

Four calves were experimentally infected via aerosol with foot-and-mouth disease virus. Two were infected with a wild-type virus derived from a full-length infectious clone (A12-IC), and two were infected with a clone-derived virus lacking the leader gene (A12-LLV2), with euthanasia and tissue collection at 24 and 72 h postexposure (hpe). Clinical disease was apparent only in the animal given A12-IC and euthanized at 72 hpe. In situ hybridization revealed that the animal infected with A12-IC and euthanized at 24 hpe had abundant viral nucleic acid in the lung, present in clusters of positive cells in the respiratory bronchiolar epithelium and associated subepithelial regions. At 72 hpe in the A12-IC-infected calf, viral nucleic acid in the lung was present in interstitial areas, and in addition, viral nucleic acid was detectable in epithelial tissues around histologically apparent vesicles. In animals infected with A12-LLV2, viral nucleic acid was detectable in the lung at both 24 and 72 hpe, but staining revealed a more localized distribution with less nucleic acid than was found in animals given A12-IC. Therefore, it appears that after aerosol exposure to A12-IC, early replication is in the region of the lung, with subsequent dissemination to distal sites. In comparison, the A12-LLV2 virus is much less widely disseminated in the lung at 24 hpe, with no lesions or virus detectable in secondary sites at 72 hpe. The greatly reduced pathogenicity of A12-LLV2 may make it an excellent candidate for a modified live viral vaccine.     

Conforming strategies of public health campaigns to disease specificity and national contexts: Rockefeller Foundation's early campaigns against hookworm and malaria in Brazil

The early experience of Rockefeller Foundation in Brazil, starting in 1915, reflected the idea of extending learned experience in Southern US to a wide international context. Health education and the creation of permanent local health services were expressed as main guidelines for cooperation with State and federal Brazilian agencies. Translating to the shaping of public health models the terms of scientific hygiene associated with the pastorian revolution, RF pictured different actions as part of a three step rationale of survey, experiment and demonstrations. In this paper we focus on Lewis Hackett's campaign, designed as a demonstration campaign of the "intensive method" of hookworm control, with the final purpose of enlisting local agencies in long-term action (1919-1924) and the malaria campaign in Rio de Janeiro State Lowlands (1922-1928) led initially by Mark Boyd as an "experimental control work" of field observation, campaign, control and maintenance to set guidelines to malaria control in tropical areas. The course and ultimate results of these experiences showed the need to adapt formal models to complex national and State-building context and to disease specificity, leading to pragmatic adaptations in the issue of control and eradication and on the shaping of vertical and horizontal health services. The failure of these two experiences in terms of disease control helped to strengthen the move, predominant in the next two decades, to vertical campaigns with least dependency on local social and political dynamics, as in the exemplar case of Frederick Soper's Anopheles gambiae eradication campaign (1938-1942).     

Positron emission tomography for the evaluation of pancreatic disease

Efficient techniques for native-labeling of amino acids have been combined successfully with emission tomography to yield significant improvements in pancreatic imaging. Carbon-11-labeled tryptophan appears to be the best agent available currently for imaging the pancreas. Optimum scanning times begin 30 min after tracer administration. Positron emission tomography with 11C-tryptophan is capable of defining both morphological and functional alterations in the pancreas. Tumors as small as 2 cm in diameter can be detected, but reliable differentiation of pancreatic cancer from pancreatis may not be possible even with this improved imaging technique. Longitudinal multiplane emission tomography in single-photon mode with the Pho/Con provides an efficient and satisfactory approach to pancreatic imaging with the positron-emitting radiopharmaceuticals.     

Autonomic control of cardiovascular function: clinical evaluation in health and disease

The high- and low-pressure baroreceptor reflexes are integral to the control of blood pressure by the autonomic nervous system. Tests of the integrity of these baroreflexes make it possible to identify the site of autonomic dysfunction in patients with orthostatic hypotension. Clinical characteristics and typical results of autonomic testing in patients with autonomic failure, with carotid sinus hypersensitivity, and with hyperadrenergic autonomic dysfunction are described in this review.     

Seroepidemiologic study on the feasibility of screening for the antibody to HCV by pooling the serum specimens

The feasibility of screening for the antibody to HCV by pooling 10 serum specimens was studied by utilizing the epidemiologic method of single blind random allocation. We changed only the ratio between the pooled serum specimen volume and the serum specimen diluent volume, with their total volume and single serum specimen volume being as much as the volume required by EIA. Other steps were the same as those of EIA. The result showed that taking single serum specimen as the control group, the sensitivity and specificity of pooled serum specimen were 100% and 97.6%, respectively. The false positive rate was 2.4%, Kappa value was 0.95 (P < 0.05). The analysis of profit found that remarkable social and economic benefit will be obtained when serum pooling method is used. These results demonstrate that pooling 10 serum specimens is feasible to screening the antibody to HCV in blood donors by EIA.     

Seroepidemiologic study of HCV genotypes in the district of Messina and Catania

Aim of the study was to identify the different hepatitis C virus (HCV) genotypes in chronic hepatitis patients living in the districts of Messina and Catania (Sicily, Italy), for epidemiological reasons but also to determine the effect of interferon therapy on therapeutic response of different viral genotypes. Genotyping was carried out by reverse-hybridization after amplification by polymerase chain reaction. The study was conducted on 271 patients with HCV-RNA positive chronic liver disease belonging to categories at risk or not for infection. HCV genotype sub-type 1b was the most common viral genotype identified.     

The impact of live animal importation on the epizootiology of foot-and-mouth disease in Saudi Arabia

Saudi Arabia imports annually more than 6 millions live ruminants for slaughter. The majority of these animals are imported from countries where foot-and-mouth disease (FMD) is enzootic. Serotypes of FMD virus not incorporated in the vaccine currently used in Saudi Arabia (e.g. SAT1 and SAT2) are prevalent in some of these exporting countries, and in others, the prevalent serotypes of FMD virus are not routinely typed. The previous exposure of imported animals to field FMD virus in the countries of origin has been confirmed by the detection of precipitating antibodies against virus infection associated (VIA) antigen and neutralizing antibodies against serotypes O, A, C and/or Asia1 of FMD virus in the sera of some imported animals. However, no isolation of FMD carrier virus could be made from 209 proband samples collected from sheep and goats imported from countries where FMD is enzootic. The significance of the obtained results is discussed. Particular emphasis has been placed on the possibility of importing either carrier animals which might act as potential source of infection or subclinically infected animals which might actively excrete FMD virus. In addition recommendations are made to reduce the risks of introducing exotic FMD virus strains to the Kingdom through live animal importation.     

Conformational preferences of a peptide corresponding to the major antigenic determinant of foot-and-mouth disease virus: implications for peptide-vaccine approaches

The conformational preferences in solution of a peptide corresponding to the GH loop of the VP1 capsid protein from the foot-and-mouth disease virus were examined by proton nuclear magnetic resonance and circular dichroism. The GH loop is the major antigenic determinant of the virus and participates in cell attachment through an integrin-like Arg-Gly-Asp sequence. The synthetic peptide, corresponding to residues Gly132 to Ser162 of the VP1 capsid protein of the serotype O, is largely disordered in aqueous solution as shown by the absence of long- and medium-range NOE contacts and by random-like chemical shifts values. Helical contents in aqueous solution were estimated to be less than 10%, as determined by extrapolation of trifluoroethanol titration from CD measurements, in good agreement with estimations from NMR experiments. In the presence of 40% trifluoroethanol an alpha-helix, flanked by two proline residues between Asn12 (Asn143 in the intact protein) and Leu28 (159), is induced. This contrasts with the 3(10) helix observed between residues Leu148 and Val155 in the crystal structure of the dithiothreitol-reduced virus, indicating that the cosolvent does not stabilize a residual, low-populated structure, similar to that in the intact virus. Several algorithms also fail to predict the structure found in the intact virus because these are based mainly on local sequence information. The lack of structure of the peptide in aqueous solution strongly suggests that the conformational determinants sufficient for the structure stabilization of this highly immunogenic antigen are mostly dictated by interactions of the loop with other regions of the virus structure, and do not arise from local amino acid sequence information. The ability of designed GH-VP1 peptides to neutralize anti-virus antibodies is likely to arise from antibody-induced conformation of the peptide and its application as peptide vaccines is not straightforward. Similarly, insertion of these peptides in carriers or macromolecular assemblies as vaccine vectors would depend on the conformation adopted at the insertion site and its success cannot be predicted.     

Validation of an inhibition ELISA using a monoclonal antibody for foot-and-mouth disease (FMD) primary diagnosis

An inhibition ELISA (IH-ELISA) test for foot-and-mouth disease virus (FMDV) was validated using 106 epithelial samples from suspected cases of FMD in Argentina submitted to the Argentine National Diagnostics Laboratory (GELAB) over a period of 12 months and examined in parallel with the complement fixation test (CFT). IH-ELISA was found to be more sensitive, detecting 25% (26 samples) more FMDV positives than the CFT in original suspensions of field samples. The effect of storage conditions on 12S stability was examined. Plates stored at 4 degrees C blocked with 1% ovalbumin and plates stored at -20 degrees C with or without blocking buffer could be used for at least 90 days. When various brands of polystyrene plates were compared for 12ps adsorption it was found that those microplates of higher binding capacity were more efficient.     

Structure of the foot-and-mouth disease virus leader protease: a papain-like fold adapted for self-processing and eIF4G recognition

The leader protease of foot-and-mouth disease virus, as well as cleaving itself from the nascent viral polyprotein, disables host cell protein synthesis by specific proteolysis of a cellular protein: the eukaryotic initiation factor 4G (eIF4G). The crystal structure of the leader protease presented here comprises a globular catalytic domain reminiscent of that of cysteine proteases of the papain superfamily, and a flexible C-terminal extension found intruding into the substrate-binding site of an adjacent molecule. Nevertheless, the relative disposition of this extension and the globular domain to each other supports intramolecular self-processing. The different sequences of the two substrates cleaved during viral replication, the viral polyprotein (at LysLeuLys/GlyAlaGly) and eIF4G (at AsnLeuGly/ArgThrThr), appear to be recognized by distinct features in a narrow, negatively charged groove traversing the active centre. The structure illustrates how the prototype papain fold has been adapted to the requirements of an RNA virus. Thus, the protein scaffold has been reduced to a minimum core domain, with the active site being modified to increase specificity. Furthermore, surface features have been developed which enable C-terminal self-processing from the viral polyprotein.