Laboratory Test Methods Research Articles

Metagenomic next-generation sequencing in the family outbreak of psittacosis: the first reported family outbreak of psittacosis in China under COVID-19

ABSTRACT Chlamydia psittaci infection in humans, also known as psittacosis, is usually believed to be an uncommon disease which mainly presents as community-acquired pneumonia (CAP). It is usually sporadic, but outbreaks of infection may occasionally occur. In outbreaks, diagnosis and investigations were usually hampered by the non-specificity of laboratory testing methods to identify C. psittaci. In this study, we use metagenomic next-generation sequencing (mNGS) in the diagnosis of a family outbreak of psittacosis under COVID-19. Three members of an extended family of 6 persons developed psittacosis with pneumonia and hepatic involvement with common symptoms of fever and weakness. Two newly purchased pet parrots, which had died successively, were probably the primary source of infection. Imagings show lung consolidations and infiltrates, which are difficult to be differentiated from CAP caused by other common pathogens. mNGS rapidly identified the infecting agent as C. psittaci within 48 h. The results of this work suggest that there are not characteristic clinical manifestations and imagings of psittacosis pneumonia which can differentiate from CAP caused by other pathogens. The use of mNGS can improve accuracy and reduce the delay in the diagnosis of psittacosis especially during the outbreak, which can shorten the course of the disease control. Family outbreak under COVID-19 may be related to the familial aggregation due to the epidemic. To our knowledge, this is the first reported family outbreak of psittacosis in China, and the first reported psittacosis outbreak identified by the method of mNGS in the world.

A two minute liquid based sample preparation for rapid SARS-CoV2 real-time PCR screening: A multicentre evaluation.

Apart from major health concerns associated to the SARS-coronavirus-2 (SARS-CoV-2) pandemic, also the diagnostic workflow encountered serious problems. Limited availability of kit components, buffers and even plastics has resulted in suboptimal testing procedures worldwide. Alternative workflows have been implemented to overcome these difficulties. Recently a liquid based sample prep has been launched as solution to overcome limitations in relation to nucleic acid extraction. Multicenter evaluation of the QIAprep&amp Viral RNA UM kit (QIA P&A) for rapid sample preparation and real-time PCR detection of SARS-CoV-2 in comparison to standardized laboratory testing methods. Selected samples of the routine diagnostic workflow at Clinical Microbiology Laboratories of four Dutch hospitals have been subjected to the rapid QIA P&A protocol and the results have been compared to routine diagnostic data. Combining results of manual and automated procedures, a total of 377 clinical samples of which 202 had been tested positive with a wide range of CT values, showed almost complete concordance in the QIA P&A assay for samples up to CT values of 33 with one exception of CT 31. Prospectively 60 samples were tested and also showed 100 % concordance with 5 positives. The method has been automated by two centres. Despite an input of only 8 μL of clinical sample, the QIA P&A kit showed good performance for sample preparation and amplification of SARS-CoV-2 and can contribute as a rapid molecular testing strategy in managing the CoV-2 pandemic.

A novel method for testing the fatigue performance of cement stabilized base field coring samples

Cement stabilized macadam (CSM) being widely used material in pavement base and subbase layers, its service performance and fatigue life need to be evaluated accurately. While laboratory testing using field coring samples seems to be a direct approach, there is no testing standard for CSM field coring or fatigue test over its service life yet. This paper proposes a novel testing method for field coring and laboratory testing for the fatigue life of CSM, which can be further used to estimate the residual life of the CSM base and subbase courses. The method makes use of the differential traffic loading in the transverse direction of a pavement section to build-up control groups. To reduce the errors caused by the variability in tensile strength between the specimens in one group, a Twin-Specimens Method is proposed, by which one specimen is tested for the tensile strength while the other one of the twin for the fatigue life. To further reduce the variability, the semi-circular bending (SCB) test was recommended becaues of its least variation of testing results among three competing tensile strength testing methods. Based on a comprehensive fatigue life experimental study based on 116 coring samples drilled from a 10-year-old freeway in central China, the SCB strength was found to be about 3 times of the indirect tensile (IDT) testing strength, and the four-point bending (4 PB) testing strength was about 1.15 times of the IDT strength. In conclusion, the optimal method for testing the fatigue resistance of CSM using field coring samples is recommended, which can also be further used to evaluate the existing performance CSM course.

A Portable System for the Evaluation of the Degree of Pollution of Transmission Line Insulators

Surface pollution is a major cause of partial discharges in high voltage insulators in coastal cities, leading to degradation of their surface and accelerating their aging process, which may cause visible arcing, flashovers and system faults. Thus, this work provides a methodology for the assessment of the condition of insulators based on an instrument which generates a severity degree to help the electric utility team schedule maintenance routines for the structures that really need it. The instrument uses a Raspberry Pi board as the processing core, a PicoScope oscilloscope for the data acquisition and an antenna as a partial discharge sensor. The algorithms are implemented in Python, and use artificial intelligence tools, such as a convolutional network and a fuzzy inference system. Laboratory test methods for the simulation of the field pollution conditions were successfully used for the validation of the instrument, which showed a good correlation between the pollution level and the severity degree generated. In addition to that, field collected data were also used for the evaluation of the proposed severity degree, which is demonstrated to be consistent when compared with the utility’s reports and the history of the selected areas from where data were collected.

Modern approaches of vehicle suspension durability evaluation at early stages of development

Ensuring demanded service life of a vehicle is a relevant engineering problem. Currently, resolving this problem is heavily complicated. Modern tendencies of automotive industry assume shortened development cycle for new vehicles and sustaining wide lineup of cars for manufacturers. Performing long-term durability testing of vehicle subsystems is becoming limited. Meanwhile, methods of laboratory testing, which provide higher acceleration degree of damage accumulation in comparison with testing on proving ground, are progressing. Virtual simulation methods, which allow analyzing and optimizing a new design at early development stages, are becoming widespread as well. Modern durability analysis methods, based on laboratory testing and virtual analysis, and load cycle generation methods, used for testing and simulations, are considered. Some points are noted, such as an extensive use of described methods of durability research among foreign car manufacturers, and the relevance of developing this kind of durability evaluation methodology for the Russian automotive industry.

Dynamic Fatigue Tests Of Landing Gears

Abstract Landing gears are one of the main components of an aircraft. The landing gear is used not only during take-off and landing but also, in most cases, during ground manoeuvres. Due to its function, the landing gear is also one of the key safety components of the aircraft due to dissipating landing loads acting on the aircraft. The mentioned loads come from both the vertical and horizontal speeds during touchdown and by the aircraft’s losing the speed by braking. The landing gear is then loaded with constantly changing forces acting in various directions during every landing, with the only difference coming from their magnitude. The repeatable loading conditions cause significant wear of the landing gear. This wear can be divided into two categories, one is the wear of consumable parts such as the brake linings and the other is the fatigue wear of the structural components. The latter type of wear is much more dangerous due to its slow, and in many cases, unnoticeable progression. Fatigue wear can be estimated by numerical analyses – this method works with a great degree of probability on single components but due to the complexity of the landing gear as a whole it is not precise enough to be applied to the full structure. In order to evaluate the fatigue of the whole landing gear the best method accepted by regulations is the laboratory testing method. It involves a series of various drop tests resembling the real landing condition distribution. The aim of the tests is to check the fatigue wear of the landing gear and to prove its reliability for certification and/or operational purposes. In this paper the author describes the basics of the landing gear fatigue wear, possibilities of its evaluation and presents laboratory dynamic method used for extensive tests in life-like operation conditions.

New Relationship between Linear Shrinkage and Shrinkage Limit for Expansive Soils

In Indonesia’s engineering practice, a standard laboratory test method to describe the characteristics of expansive soils is the shrinkage limit (ASTM). Expansive soils are problematic soils that have shrinkage and swelling history due to changing water content on a particular clay mineral type (i.e., montmorillonite). Another method rare using in general practice in our country is the linear shrinkage (British Standard). The last test is easier and faster to obtain than the shrinkage limit method. Some researchers proposed swelling potential classification for expansive soils using a specific range of shrinkage limits or linear shrinkage. This research aims to give a new relationship between both methods using available laboratory test results database. There were two sets of data: first, complete laboratory data (i.e., 124 samples of shrinkage limit and linear shrinkage); and second, only Atterberg limits (i.e., liquid limit and plastic limit) results (i.e., 86 samples). For the latter database, shrinkage limit and linear shrinkage use previous researchers’ empirical equations. Then, these two datasets are compared and give a similar trend. The results show that if increasing of shrinkage limit is followed by decreasing of linear shrinkage. This result may help geotechnical engineers to obtain the linear shrinkage directly from our proposed Equation and shrinkage limit value. Hence, our research has a contribution to know the characteristics of the expansive soil (i.e., swelling potential).

Dynamic Modulus Predictive Models for In-Service Asphalt Layers in Hot Climate Areas

Dynamic modulus of asphalt mixtures is one of the most important input parameters in design and rehabilitation of asphalt pavements. Dynamic modulus predictive models are alternative methods for laboratory determination of this parameter. These models were developed based on laboratory data. Due to sophisticated and laborious laboratory testing methods, there is a need to develop new models to determine dynamic moduli of in-service asphalt layers. In this study, nine different asphalt pavement sites were selected in two southern provinces of Iran. Falling weight deflectometer (FWD) testing was performed at each site and core samples were taken from the asphalt layers for volumetric analysis. Using the results, dynamic moduli of asphalt layers were determined using six predictive models, including Witczak, modified Witczak, Hirsch, Al-Khateeb, global, and simplified global models. Predicted dynamic moduli were compared with those determined from back-calculation analysis of FWD data. Existing predictive models were calibrated and new models were developed for the prediction of in situ dynamic modulus of asphalt layers in hot climate areas. Performance evaluation and validation of the new models showed high prediction accuracy and low prediction bias with very good correlations between the predicted and back-calculated values (R2=0.96).

Comparative investigation on three laboratory testing methods for short-term aging of asphalt binder

As one type of organic binder, asphalt is prone to aging under climatic conditions such as temperature, oxygen, water, sunlight, etc., which is one of the principal factors causing the performance degradation (raveling, potholes, cracking) of asphalt pavement. In addition to long-term aging, short-term aging of asphalt binder will also have an important impact on the performance of asphalt pavement. As the most commonly used short-term aging methods, the Thin Film Oven Test (TFOT) and Rolling Thin Film Oven Test (RTFOT) still have some problems to be studied, such as the convenience of test operation, the difference of aging degree between them and whether they can be applied to a wide variety of polymer modified asphalt binders. Some scholars have proposed that the aging effect of the 5 h Pressurized Aging Vessel (5 h PAV) test is equivalent to RTFOT, which can be used as an alternative to each other. However, this is limited to preliminary verification and lacks sufficient proof. Therefore, three types of short-term aging methods (TFOT, RTFOT and 5 h PAV) were carried out for four types of asphalt binders at first in this paper. Then, Dynamic Shear Rheometer (DSR), Fourier Transform Infrared Spectroscopy (FT-IR) and Gel Permeation Chromatography (GPC) were used to carry out the comprehensive macroscopic rheological and micro chemical evaluation of asphalt samples before and after aging, and compare the aging effect of different short-term aging processes. Finally, it is concluded that 5 h PAV can replace TFOT for 70# asphalt and RTFOT can be replaced by 5 h PAV for modified asphalt. It is of great significance to improve the convenience of asphalt short-term aging test and explore the aging method of asphalt mortar.

Coupling effects of physical and chemical properties on jet fuel spray flame blowout

This work uses an annular co-flow spray burner as a laboratory test method for evaluating one of the important jet fuel figures of merit, namely lean blowout (LBO), and investigates the coupling of physical and chemical properties affecting this phenomenon. Previous work has shown that relative trends in LBO from different fuels in a real gas turbine are well reflected in this burner setup. Representative characteristics for fuel heat of combustion, volatility, atomization, and pressure are used to produce correlations predicting the LBO for this spray burner, thus these characteristics are considered important toward the prediction of LBO in real gas turbine combustors. The results of this testing are compared to general relations for spray flames as published in prior literature; it is found that equivalence ratio at LBO is positively correlated to fuel flow rates and effective evaporation, and inversely correlated to combustion pressure, heat of combustion, and spray droplet diameter. Using simultaneous OH Planar Laser Induced Fluorescence and Mie scattering imaging of the spray and flame structure, the liquid loading in the flame region is also analyzed for surrogate jet fuels which have comparable derived cetane number (DCN) but have very different compositions. Characteristics that can affect the amount of liquid fuel entering the flame region in near-LBO conditions are discussed. The use of surrogates allows for discussion of the competing effects of volatility and reactivity of fuel components. It is found that the most stable flames occur when the interplay of fuel atomization/volatility and reactivity result in substantial penetration of fuel droplets containing components with high DCN.

Deterioration of non-persistent rock joints: A focus on impact of freeze–thaw cycles

Existing research on rock freeze-thaw mainly focuses on a single freeze-thaw process, while little attention is paid to the cumulative effect of cyclic freeze-thaw on rock mass joints. However, the accumulated freeze-thaw effects are precisely the leading cause of rock mass deterioration and damage in severe cold regions. This study aims to investigate the use of a novel laboratory testing method, i.e., membrane pressure sensors in the joint, to demonstrate the impact of cyclic frost-thaw on jointed rocks. With the sensors, the change of frost-heaving pressure in the joint under cyclic process is continuously monitored. The measurements indicate that under freeze-thaw cycles, the initiation of frost-heaving pressure is critical, which is followed by an explosion, stability, and ablation stages. In these stages, the maximum frost-heaving pressure is observed to emerge at the early stage of the freeze-thaw cycle. Based on the experimental observations, frost-heaving pressure evolution law and damage mechanism of jointed rock masses are analyzed. For example, the peak frost-heaving pressure increases exponentially with the decrease of temperature and decreases exponentially with the increase of freeze-thaw cycles. Also, the pressure has a positive linear relationship with the geometric size of the joint. In essence, the deterioration of freeze-thaw cycles on jointed rock masses is mainly due to crack propagation caused by the frost-heaving pressure.

Distribution patterns of rock mass displacement in deeply buried areas induced by active fault creep slip at engineering scale

Active fault creep slip induces deformation of rock mass buried deeply in fault zones that significantly affect the operational safety of long linear projects passing through it. Displacement distribution patterns of rock masses in active fault zones which have been investigated previously are the key design basis for such projects. Therefore, a discrete element numerical model with different fault types, slip time, dip angles, and complex geological features was established, and then the creep slip for normal, reverse, and strike-slip faults were simulated to analyze the displacement distribution in the fault rock mass. A disk rotation test system and the corresponding laboratory test method were developed for simulating rock mass displacement induced by creep slippage of faults. A series of rotation tests for soft-and hard-layered specimens under combined compression and torsional stress were conducted to verify the numerical results and analyze the factors influencing the displacement distribution. An S-shaped displacement distribution independent of fault dip angle was identified corresponding to reverse, normal, and strike-slip faults. The results indicated that the higher the degree of horizontal extrusion, the softer the rock mass at the fault core, and the higher the degree of displacement concentration in the fault core; about 70% of the creep slip displacement occurs within this zone under 100 years of creep slippage.

Substantiation of Drinking Water Quality Testing Methods of Choice for the Goals and Objectives of Sanitary and Epidemiologic Expert Examination and Health Risk Assessment

Summary. Introduction: As the most important environmental factor having multiple effects on human vital activities and health, drinking water often becomes the subject of predicting adverse health effects. With the purpose of establishing quantitative and/or qualitative characteristics of harmful effects of drinking water chemicals for human health, an integral assessment of drinking water quality with subsequent health risk assessment is carried out. It is based on estimating the risk posed by chronic (carcinogenic and non-carcinogenic) exposures that shows probability of developing a disease. Results: Practical activities of departments and institutions of the Federal Service for Surveillance in the Sphere of Consumers Rights and Human Wellbeing (Rospotrebnadzor) on assessing health effects of environmental factors have demonstrated that, even in concentrations equaling their detection limits in quite a number of test methods, most chemical water pollutants pose unacceptable carcinogenic and non-carcinogenic risks both for the general population and occupational cohorts. Thus, the results of some laboratory methods of testing are inappropriate for an objective human health risk assessment. Conclusions: We describe criteria for selecting methods of the quantitative chemical analysis of drinking water fit for the purposes of sanitary and epidemiologic expert examination combined with a population health risk assessment. The criteria of choice have been elaborated based on the review of regulatory and method documents and results of analytical testing of drinking water quality.

Strain evolution of saturated clays under cyclic loadings in three-dimensional stress condition

The strain evolution of saturated clays under cyclic loadings has been studied by means of various laboratory testing methods, aiming for the accurate simulation of engineering conditions such as the consolidation states of clays, cyclic stress paths of external loadings and boundary conditions in situ. Considering that the subgrade clays are usually overconsolidated rather than normally consolidated, the drainage condition is normally partially drained instead of undrained under long-term cyclic loadings, and the cyclic stress paths are in three-dimensional stress state, this study explores the three-dimensional strain characteristics of both normally and overconsolidated clays in partially drained condition based on a true triaxial apparatus. Emphasis are put on the effects of cyclic stress ratio (CSR), overconsolidation ratio (OCR) and coefficient of cyclic intermediate principal stress (bcyc) on the accumulation of permanent strain components including major, intermediate, minor principal strains, and volumetric strain. Test results show that the relative magnitudes of strain components are strongly influenced by both bcyc and OCR, while the accumulated directions of strain paths tend to be identical for various bcyc values. The increase of bcyc leads to a linear growth of permanent volumetric strain for both normally and overconsolidated clays, while the permanent major principal strain shows a firstly increasing and then decreasing trend versus the increase of bcyc. For the normally consolidated and overconsolidated clays, the largest permanent major principal strains are achieved at around bcyc = 0.4 and 0.2, respectively. The accumulation of permanent intermediate principal strain is always promoted by the increase of bcyc. In addition, the development of permanent major principal and volumetric strains with cycle number is analyzed in the double logarithmic plane, which are found to be combined by two linear parts.

Methods of specific laboratory testing of new coronavirus infection

The review presents a description of the specific laboratory testing of SARS-CoV-2. The effectiveness of certain types of tests depending on the set medical and epidemiological tasks is shown. The importance of using certain diagnostic methods for mass and rapid testing of patients for a new coronavirus infection, which will speed up their detection, was also noted. The effectiveness of using test systems that can be used in outpatient settings without the presence of a stationary laboratory in a medical facility is shown, which will simplify and increase the throughput of medical institutions that perform SARS-CoV-2 diagnostics. This review will be useful for both medical professionals of laboratory specialties and all clinical doctors who are currently working with a new coronavirus infection.

Comparative laboratory measurement of pervious concrete permeability using constant-head and falling-head permeameter methods

The permeability characteristics is one of the most important properties of pervious concrete (PC), which represents the ability of water on the surface to drain through the pervious pavement structure. Its measuring is a sensitive key on the pervious concrete. Thus, this paper presents the experimental results of two commonly used laboratory test methods to measure the permeability of pervious concrete; namely falling-head (FH) method and constant-head (CH) method, to investigate the relationship between the examined methods and select the reliable method. Moreover, study the effect of aggregate gradation and ratio of cement to aggregate on the permeability of PC. Therefore, thirty-six groups of pervious concrete specimens with twelve different types of gradation and three kinds of ratios of cement to aggregates were prepared in this study. The comparison between the two methods to evaluate which method is more suitable includes: the precision, the cost of the experimental equipment, the convenience of the test operation process and the time required for the test. The results showed that the permeability values measured by the falling-head method were significantly higher than those measured by the constant-head method and it is more convenient compared to the constant-head method. Effect of aggregate gradation on porosity and permeability was examined in this study. Correlation between porosity and permeability was investigated, and a new model between FH and CH methods was established.

On-machine visible dirt measurement on moving sheets and the relationships to standard laboratory methods

There has been a proliferation of new sensors to measure on-machine dirt specks that employ different technologies and methodologies to perform measurements. The differences in the on-machine technologies are discussed in terms of the TAPPI and ISO standard laboratory test methods with respect to dirt detection using light reflected from, or light transmitted through, the sheet. Also discussed are the requirements for measuring statistically representative areas of the sheet; the difference between the dirt physical size and Equivalent Black Area (EBA) size; and the implication of these issues when specifying cleanliness acceptance criteria. This technical brief describes on-machine visible dirt measurement’s relationship to standard laboratory testing.

Laboratory Test Methods for Assessing the Abrasivity of Rocks and Soils in Geotechnology and Mining Applications

Abstract In geotechnology and mining, tools and equipment interact with aggressive geological material, causing the wear of these components. For this reason, it is important to determine the rate of abrasivity of individual geological materials, depending on the type of interaction with the tool. Various abrasivity tests have been developed in laboratories. Some of them are general, while others are special. What they all have in common is that they attempt to determine the abrasivity of rocks or soils in relation to the wear of the test specimens. This article gives an overview of the laboratory test methods for assessing the abrasivity of geological materials, which are useful in the field of geotechnology and mining engineering. General and special abrasivity tests are presented in detail. The aim of the article is to present existing laboratory tests to assess the abrasivity of rocks and soils, based on which further investigations of wear can be considered as part of a comprehensive approach to this tribological problem. Understanding of the wear mechanisms is the basis for the development of wear-resistant tools and models for predicting the tool life.

Abstract 4256: Multiplex fast FISH assay for detecting ROS1, RET and MET aberrations in FFPE specimens using BioView image analysis

Abstract Background: Biomarker testing in lung cancer is often limited by a lack of sufficient formalin fixed, paraffin embedded (FFPE) tissue for comprehensive genomic profiling. To promote personalized therapy for lung cancer, a multiplex FISH assay was developed to simultaneously assess aberrations in ROS1, RET, and MET on a single FFPE specimen slide. Methods: Specimens included primary tumor (N = 39) as well as biopsies from a variety of metastatic sites (N = 16). These included 12 samples with ROS1 rearrangements, 3 samples with RET rearrangements, and 11 samples with MET amplification reported by a previously validated laboratory test method. A probe mix contained 6 differentially labeled fluorescent probes: 3' ROS1, 5' ROS1, 3' RET, 5' RET, MET and CEP7. The probes were formulated in Vysis IntelliFISH Hybridization Buffer to allow for a 2 h hybridization time. BioView imaging platform and Duet software algorithm were used to perform automated slide scanning and digital analysis. Specimens were considered positive for ROS1 or RET rearrangement if >15% evaluated cells contained a break apart (rearranged) signal. Specimens were considered positive for MET amplification if >15% of cells had MET/CEP7 ratio >2 and positive for polysomy if >15% of cells had 5 or more MET signals copies. Results: The 6 color FISH assay was 97% concordant for ROS1 rearrangement and 100% concordant for RET rearrangement. The average background percentage of positive tumor cells in cases without known gene rearrangements was approximately 5%, yielding a negative cutoff threshold of approximately 15%, in accordance with cutoff thresholds reported in literature. The 6 color FISH assay was 91% concordant for MET amplification or polysomy. Results were interpretable for 98% of targets analyzed by the 6 color FISH method. Four samples failed on analysis for one of the targets due to lack of sufficient cells or lack of adequate hybridization signal. Conclusion: A newly developed 6-color FISH assay allows simultaneous detection of three genomic abnormalities using only 1 specimen slide. This feature combined with rapid hybridization in IntelliFISH buffer and automated BioView slide imaging and analysis can significantly increase the yield of molecular testing on limited lung cancer tissue samples. Careful pathologic correlation for tumor cell identification and careful assessment of hybridization quality are necessary to optimize the accuracy of this test method. Citation Format: Irina A. Sokolova, Patrick Bedroske, Tatyana A. Grushko, Amber R. Schneider, Kristine Jacobson, Jesse S. Voss, Yishay Tauber, Yossi Avisror, Vitaliy Shkolnik, Katerina Pestova, Katherine B. Geiersbach. Multiplex fast FISH assay for detecting ROS1, RET and MET aberrations in FFPE specimens using BioView image analysis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4256.

Laboratory Diagnosis of HTLV-1-Associated Myelopathy

Human T-lymphotropic virus type 1 (HTLV-1), a human retrovirus, is endemic in certain regions of the world and affects millions of people worldwide. Infected individuals are at risk of developing adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. Vertical and parenteral transmission are the main routes of infection. Diagnosis of HTLV-1 infection can be made by detection of HTLV-1-specific antibodies in plasma, serum, or cerebrospinal fluid using a combination of initial and supplemental serologic assays. In contrast, quantitative proviral DNA in peripheral blood mononuclear cells has been used to predict and monitor disease progression. This review provides an overview of the virology, epidemiology, transmission, pathophysiology, clinical manifestations, and laboratory testing methods for HTLV-1 infection.