Filariasis: diagnosis and treatment

Emergence of infectious diseases and role of advanced nanomaterials in point-of-care diagnostics: a review

Infectious outbreaks are the foremost global public health concern, challenging the current healthcare system, which claims millions of lives annually. The most crucial way to control an infectious outbreak is by early detection through point-of-care (POC) diagnostics. POC diagnostics are highly advantageous owing to the prompt diagnosis, which is economical, simple and highly efficient with remote access capabilities. In particular, utilization of nanomaterials to architect POC devices has enabled highly integrated and portable (compact) devices with enhanced efficiency. As such, this review will detail the factors influencing the emergence of infectious diseases and methods for fast and accurate detection, thus elucidating the underlying factors of these infections. Furthermore, it comprehensively highlights the importance of different nanomaterials in POCs to detect nucleic acid, whole pathogens, proteins and antibody detection systems. Finally, we summarize findings reported on nanomaterials based on advanced POCs such as lab-on-chip, lab-on-disc-devices, point-of-action and hospital-on-chip. To this end, we discuss the challenges, potential solutions, prospects of integrating internet-of-things, artificial intelligence, 5G communications and data clouding to achieve intelligent POCs.

[Evidence of modern diagnostic, conservative, and surgical therapy of secondary lymphoedema]

BACKGROUND

Secondary lymphoedema (SL) is one of the most common and, at the same time, most significant consequences and complications of modern oncological therapy. Although a thorough patient history and physical examination are sufficient to substantiate a suspicion, it is essential to perform functional imaging of the lymphatic system for a targeted diagnosis and determination of severity. For this purpose, techniques such as MR and ICG lymphography as well as ultra-high-frequency ultrasound examinations have been developed and validated in recent years. The selective use of these techniques has allowed for individualized indications and successful stage-dependent treatment using (super)microsurgical techniques to restore regional lymphatic drainage in the context of intensified conservative therapy.

METHOD

Systematic review of the literature on the diagnosis and treatment of SL with subsequent analysis and classification of the results into evidence levels according to the Oxford Centre for Evidence-Based Medicine and the GRADE Scale.

RESULTS

The established and validated diagnosis of SL includes imaging (ICG fluorescence lymphography, MR lymphography and Tc-99 functional lymphoscintigraphy) in case of a clinical suspicion and in high-risk patients. Complex physical decongestion therapy (CPE) is superior to physical therapy or compression alone. (Super)microsurgery of SL allows for a postoperative reduction in the frequency of CPE, a reduction of erysipelas rates, a volume reduction of the lymphomatous extremity and, if carried out prophylactically, a lower incidence of SL. Suction-assited lipectomy can produce long-term, stable reductions in circumference and an improvement in quality of life.

CONCLUSION

Patients with SL benefit from conservative therapy with regular re-evaluation. Patients with a high risk for SL or with clinical deterioration or persistent symptoms under guideline-based conservative therapy can benefit from (super)microsurgical therapy after an individualized functional diagnostic evaluation of the lymphatic system. Excisional dermolipectomies or lympholiposuctions are available and effective for advanced and refractory stages.

Beyond Tradition: Exploring Cutting-Edge Approaches for Accurate Diagnosis of Human Filariasis

Filariasis is recognised as a global public health threat, particularly in tropical and subtropical regions. It is caused by infection with a nematode parasite of the superfamily Filarioidea, including Wuchereria bancrofti, Brugia malayi, Onchocerca volvulus, and Onchocerca lupi. Three main types of filariasis have been classified: lymphatic filariasis, subcutaneous filariasis, and serous cavity filariasis. The symptoms exhibited by individuals afflicted with filariasis are diverse and contingent upon several variables, including the species of parasite, the host's health and immune response, and the stage of infection. While many classical parasitological techniques are considered indispensable tools for the diagnosis of parasitic infections in humans, alternative methods are being sought due to their limitations. Novel tests based on host-parasite interactions offer a rapid, simple, sensitive, and specific diagnostic tool in comparison to traditional parasitological methods. This article presents methods developed in the 21st century for the diagnosis of filariasis caused by invasion from W. bancrofti, B. malayi, O. volvulus, and O. lupi, as well as techniques that are currently in use. The development of modern diagnostic methods based on molecular biology constitutes a significant advancement in the fight against filariasis.

We Are Not Speaking the Same Language: Current Procedural Terminology Coding and Provision of Care in Lymphatic Reconstruction

INTRODUCTION

Current Procedural Terminology (CPT) codes provide a uniform language for medical billing, but specific codes have not been assigned for lymphatic reconstruction techniques. The authors hypothesized that inadequate codes would contribute to heterogeneous coding practices and reimbursement challenges, ultimately limiting surgeons' ability to treat patients.

METHODS

A 22-item virtual questionnaire was offered to 959 members of the American Society of Reconstructive Microsurgeons to assess the volume of lymphatic reconstruction procedures performed, CPT codes used for each procedure, and challenges related to coding and providing care.

RESULTS

The survey was completed by 66 board-certified/board-eligible plastic surgeons (6.9%), who unanimously agreed that lymphatic surgery is integral to cancer care, with 86.4% indicating that immediate lymphatic reconstruction should be offered after lymphadenectomy. Most performed lymphovenous bypass, immediate lymphatic reconstruction, liposuction, and vascularized lymph node transfer.Respondents reported that available CPT codes failed to reflect procedural scope. A wide variety of CPT codes was used to report each type of procedure. Insurance coverage problems led to 69.7% of respondents forgoing operations and 32% reducing treatment offerings. Insurance coverage and CPT codes were identified as significant barriers to care by 98.5% and 95.5% of respondents, respectively.

CONCLUSIONS

Respondents unanimously agreed on the importance of lymphatic reconstruction in cancer care, and most identified inadequate CPT codes as causing billing issues, which hindered their ability to offer surgical treatment. Appropriate and specific CPT codes are necessary to ensure accuracy and consistency of reporting and ultimately to improve patient access to care.

Development and validation of a long-read metabarcoding platform for the detection of filarial worm pathogens of animals and humans

BACKGROUND

Filarial worms are important vector-borne pathogens of a large range of animal hosts, including humans, and are responsible for numerous debilitating neglected tropical diseases such as, lymphatic filariasis caused by Wuchereria bancrofti and Brugia spp., as well as loiasis caused by Loa loa. Moreover, some emerging or difficult-to-eliminate filarioid pathogens are zoonotic using animals like canines as reservoir hosts, for example Dirofilaria sp. 'hongkongensis'. Diagnosis of filariasis through commonly available methods, like microscopy, can be challenging as microfilaremia may wane below the limit of detection. In contrast, conventional PCR methods are more sensitive and specific but may show limited ability to detect coinfections as well as emerging and/or novel pathogens. Use of deep-sequencing technologies obviate these challenges, providing sensitive detection of entire parasite communities, whilst also being better suited for the characterisation of rare or novel pathogens. Therefore, we developed a novel long-read metabarcoding assay for deep-sequencing the filarial nematode cytochrome c oxidase subunit I gene on Oxford Nanopore Technologies' (ONT) MinION™ sequencer. We assessed the overall performance of our assay using kappa statistics to compare it to commonly used diagnostic methods for filarial worm detection, such as conventional PCR (cPCR) with Sanger sequencing and the microscopy-based modified Knott's test (MKT).

RESULTS

We confirmed our metabarcoding assay can characterise filarial parasites from a diverse range of genera, including, Breinlia, Brugia, Cercopithifilaria, Dipetalonema, Dirofilaria, Onchocerca, Setaria, Stephanofilaria and Wuchereria. We demonstrated proof-of-concept for this assay by using blood samples from Sri Lankan dogs, whereby we identified infections with the filarioids Acanthocheilonema reconditum, Brugia sp. Sri Lanka genotype and zoonotic Dirofilaria sp. 'hongkongensis'. When compared to traditionally used diagnostics, such as the MKT and cPCR with Sanger sequencing, we identified an additional filarioid species and over 15% more mono- and coinfections.

CONCLUSIONS

Our developed metabarcoding assay may show broad applicability for the metabarcoding and diagnosis of the full spectrum of filarioids from a wide range of animal hosts, including mammals and vectors, whilst the utilisation of ONT' small and portable MinION™ means that such methods could be deployed for field use.

Experimental Study of the Prevention and Treatment of Lymphoedema in a Rat Hindlimb Model by Applying Cardioperitoneal Catheters and Lacrimal Intubation Tubes in the Inguinoperitoneal Region

OBJECTIVE

Secondary lymphoedema (LE) is a chronic condition with limited surgical treatment options for restoring extremity form and function. This study aimed to establish a reproducible model of secondary LE and evaluate the preventive and corrective effects of fenestrated catheters (FC) and capillary tubes (CT).

METHODS

Thirty-five rats underwent left hindlimb inguinal and popliteal lymph node dissection, followed by radiotherapy after two weeks. The right hindlimb served as the control. The rats were divided into five groups: sham, two preventive (Group 2 - EFC, Group 3 - ECT), and two corrective (Group 4 - LFC, Group 5 - LCT). Measurements of ankle circumference (AC) and paw thickness (PT) were taken weekly, and imaging modalities were performed. After a 16 week follow up, rats were euthanised for histological examination.

RESULTS

Data include paw thickness (PT) and ankle circumference (AC) ratios for hindlimbs. In the sham group, AC ratio was 1.08 (p = .002) and PT ratio was 1.11 (p = .020), confirming successful lymphoedema model establishment. Early catheter and tube placement in Groups 2 and 3 prevented AC and PT increase until the 16th week. Group 2: the AC ratio was 0.98 (p = .93), and the PT ratio was 0.98 (p = .61). Group 3: the AC ratio was 0.98 (p = .94) and the PT ratio was 0.99 (p = .11). From the 10th to the 16th week, Groups 4 and 5 exhibited reduced measurements after insertion of catheters and tubes. Computed tomography imaging as an objective examination supported the results obtained from the measurements. The histological findings confirmed the benefits of both FC and CT.

CONCLUSION

The insights gained from the present study provide a basis for further exploration and refinement of drainage system designs, ultimately leading to improved treatment approaches for individuals suffering from lymphoedema in the future.

Comparison of three PCR-based methods to detect Loa loa and Mansonella perstans in long-term frozen storage dried blood spots

OBJECTIVES

Loa loa and Mansonella perstans are two very common filarial species in Africa. Although microscopy is the traditional diagnostic method for human filariasis, several polymerase chain reaction (PCR) methods have emerged as an alternative approach for identifying filarial parasites. The aim of this study is to compare three molecular methods and decide which is the most suitable for diagnosing human loiasis and mansonellosis in non-endemic regions using dried blood spot (DBS) as a medium for sample collection and storage.

METHODS

A total of 100 DBS samples, with their corresponding thin and thick blood smears, were selected for this study. Microscopy was used as the reference method to diagnose and calculate the microfilaraemia. Filarial DNA was extracted using the saponin/Chelex method and the DNA isolated was assayed by Filaria-real time-PCR, filaria-nested PCR, and cytochrome oxidase I PCR. All PCR products were subsequently purified and sequenced. The statistical values for each molecular test were calculated and compared.

RESULTS

Overall, 64 samples were identified as negative by all tests and a further 36 samples were positive by at least one of the methods used. The sensitivity and specificity were similar for the different molecular methods, all of which demonstrated good agreement with microscopy.

CONCLUSIONS

Based on this study, and from a practical point of view (single and short amplification round), the optimal technique for diagnosing filarial infection in non-endemic regions is filaria-real time-PCR, which presents high sensitivity and specificity and is also able to detect a wide range of human filariae.

Breast Cancer related upper limb lymphedema: approach and surgical management

Lymphedema of the upper extremities in a common, chronic, progressive and debilitating disease, that affects the increasing population of cancer survivors. The gold standard is nowadays an integrated approach, including conservative and surgical treatment. Lymphatic surgery, particularly the physiologic procedures including lymphaticovenous anastomosis and vascularised lymph node transfer, should be offered to lymphedema patients as soon as possible, aimed to ameliorate the subjective symptoms and also to interrupt the degeneration cascade that makes this condition progressive over time. Indications for surgery, patient selection, and diagnostic tools will be discussed.

Outcomes of Vascularized Lymph Node Transplantation for Treatment of Lymphedema

BACKGROUND

A growing body of evidence supports the efficacy of surgical treatments for lymphedema. This study reports the outcomes of vascularized lymph node transplantation (VLNT) for the treatment of patients with lymphedema compared with maximal conservative treatment alone.

STUDY DESIGN

Consecutive patients undergoing VLNT to treat primary and secondary lymphedema affecting the upper or lower extremities were included. All patients were optimized preoperatively with conservative therapy. Demographic and treatment information was collected, and outcomes data were electronically captured prospectively; descriptive statistics were performed.

RESULTS

There were 134 patients included that had achieved maximal reductions by conservative therapy preoperatively. This series included jejunal mesenteric (n = 25), groin (n = 43), lateral thoracic (n = 31), omental or right gastroepiploic (n = 21), and submental (n = 14) VLN flaps. At 24 months postoperatively, there were significant reductions in limb volume change (mean [SD] 45.7% [8.7%]; p = 0.002) LDex score (mean [SD] 59.8% [8.7%]; p < 0.001), Lymphedema Life Impact Scale score (mean [SD] 61.6% [5.9]; p < 0.001), and cellulitis episodes (97.9%; p < 0.001). At 3 and 6 months postoperatively, limb volume change was significantly greater for the upper than the lower extremity, otherwise outcomes were similar. There were no flap losses and overall outcomes were similar between the different VLN flap types.

CONCLUSIONS

Treatment of lymphedema using VLNT resulted in progressive, significant reductions in limb volume, bioimpedance spectroscopy measurements of extracellular fluid, and episodes of cellulitis, with improved patient-reported outcomes and limb function measures compared with maximal conservative therapy alone. The complication rate was low and there were no significant outcomes differences between the VLNT types.

A Murine Tail Lymphedema Model

Lymphedema is extremity swelling caused by lymphatic dysfunction. The affected limb enlarges because of accumulation of fluid, adipose, and fibrosis. There is no cure for this disease. A mouse tail model that uses a focal full thickness skin excision near the base of the tail, resulting in tail swelling, has been used to study lymphedema. However, this model may result in vascular comprise and consequent tail necrosis and early tail swelling resolution, limiting its clinical translatability. The chronic murine tail lymphedema model induces sustained lymphedema over 15 weeks and a reliable perfusion to the tail. Enhancements of the traditional murine tail lymphedema model include 1) precise full thickness excision and lymphatic clipping using a surgical microscope, 2) confirmation of post-operative arterial and venous perfusion using high resolution laser speckle, and 3) functional assessment using indocyanine green near infrared laser lymphangiography. We also use tissue nanotransfection technology (TNT) for novel non-viral, transcutaneous, focal delivery of genetic cargo to the mouse tail vasculature.

Shaving Technique and Compression Therapy for Elephantiasis Nostras Verrucosa (Lymphostatic Verrucosis) of Forefeet and Toes in End-Stage Primary Lymphedema: A 5 Year Follow-Up Study in 28 Patients and a Review of the Literature

Background. Longstanding lymphedema can lead, especially when there is recurrence of erysipelas, to irreversible elephantiasis nostras verrucosa (ENV). This predisposes to new episodes of erysipelas, leading to further damage of the lymphatics and deterioration of the lymphedema as a whole. We report the results of 28 patients with primary lymphedema and surgical removal ENV of the forefoot and toes treated between 2006 and 2014. Method: Retrospective descriptive 5 year follow-up study of 28 patients with various diagnosis of primary lymphedema. Wound healing time, number of erysipelas, body mass index (BMI), recurrence of EVN and types of compression were documented during follow-up. Results: After preoperative multidisciplinary work up, operation of the toes with shaving and excision was performed within a conservative treatment program. During the follow up, the number of erysipelas attacks decreased dramatically (mean 17.6 vs. 0.6). Before treatment, no toecaps were used; and in follow up, it was a part of treatment. Recurrence of ENV was not observed. Compared to the literature with often BMI > 35, the mean BMI in our group was 30.0 (overweight). In 12 patients, we concurrently performed circumferential suction-assisted lipectomy for end-stage lymphedema of the leg. Conclusion: Although lymphedema patients are treated with garments during the maintenance phase, compression of the toes is often too challenging. Surgical removal of the verrucosis of toes is an effective therapeutic modality as part of an integrated lymphedema treatment program to restore the shape of the toes and enable the wearing of toecaps. This technique can also be effective for ENV of origins other than primary lymphedema. Although ENV is a generally accepted term, it can have undesirable connotations. We suggest using a more inclusive name such as lymphostatic verrucosis, because long-lasting lymphatic impairment is involved in all ENV and the term verrucosis is above discussion.

Patients Radiation Risks from Computed Tomography Lymphography

Objectives:

This study aims to first measure patient doses during computed tomography (CT) chest, abdomen, and extremities procedures for evaluation lymphedema, and second to estimate the radiation dose-related risks during the procedures.

Material and Methods:

Radiation effective doses from CT lymphography procedures quantified using CT machines from different vendors. After the calibration of CT systems, the data collected for a total of 28 CT lymphography procedures. Effective and organ doses extrapolated using national radiological protection software based on Monte Carlo simulation.

Results:

The mean patient doses for chest and abdomen procedures in term of CTDIvol (mGy) and DLP (mGy.cm) are 10.0 ± 3 and 425 ± 222 and 24 ± 12 and 1118 ± 812 for CT 128 and CT 16 slice, respectively. The mean DLP (mGy.cm) for extremities was 320 ± 140 and 424 ± 212 for CT 128 and CT 16 slice, in that order.

Conclusion:

Patients’ dose showed significant differences due to variation in the scan length and clinical indication. Organs lay in the primary beam received high radiation doses especially in the chest region which increases the probability of radiation-induced cancer. The current patient’s doses are higher compared to the previous studies.

Surgical treatment of lymphedema

Lymphedema is a debilitating and progressive condition, which results in the accumulation of lymphatic fluid within the interstitial compartments of tissues and hypertrophy of adipose tissue due to the impairment of lymphatic circulation. The mainstay of current lymphedema treatment is nonsurgical management such as complex decongestive therapy and compression therapy. Recently, surgical treatment of lymphedema based on microsurgery has been developed to enable the functional recovery of lymphatic drainage and has complemented nonsurgical treatment. Lymphaticovenular anastomosis and vascularized lymph node transfer are representative physiologic surgeries in the treatment of lymphedema. Lymphaticovenular anastomosis is conducted to drain lymphatic fluid from obstructed lymphatic vessels to the venous circulation through surgically created lymphaticovenous shunts. Vascularized lymph node transfer involves harvesting lymph nodes with their vascular supply and transferring this vascularized tissue to the lymphedema lesion as a free flap. In addition to physiologic surgeries, ablative surgeries such as direct excision and liposuction also can be performed, especially for end-stage cases. Indications for surgical treatment vary across institutions. It is important not to delay physiologic surgery in mild to moderate cases of lymphedema.

The Efficacy of Doxycycline Treatment on Mansonella perstans Infection: An Open-Label, Randomized Trial in Ghana

Treating Mansonella perstans is challenged by the low efficacy of registered antihelminthics. Wolbachia endobacteria provide an alternative treatment target because depletion results in amicrofilaremia in filarial infections with Wuchereria bancrofti and Onchocerca volvulus infections. This open-label, randomized study sought to confirm that i) Wolbachia are present in M. perstans in Ghana and ii) doxycycline treatment will deplete Wolbachia and cause a slow, sustained decline in microfilariae (MF). Two hundred and two Ghanaians with M. perstans infection were randomized into early (immediate) and delayed (6 months deferred) treatment groups, given doxycycline 200 mg/day for 6 weeks, and monitored for MF and Wolbachia levels at baseline, 4, 12, and 24 months after the study onset (= time of randomization and start of treatment for the early group). Per protocol analysis revealed that the median MF/mL in the early group declined from 138 at baseline to 64 at month 4 and further to 0 at month 12. In the delayed group, MF load did not change from a baseline median of 97 to 102 at month 4 but declined to 42 at month 12, that is, 6 months after receiving treatment, trailing the early group as expected. By month 24, both treatment groups had reached a median MF level of 0. After treatment, Wolbachia were depleted from MF by ≥ 1-log drop compared with baseline levels. We conclude that M. perstans in Ghana harbor Wolbachia that are effectively depleted by doxycycline with subsequent reduction in MF loads, most likely because of interruption of fertility of adult worms.

Preoperative planning of lymphaticovenous anastomosis: The use of magnetic resonance lymphangiography as a complement to indocyanine green lymphography

BACKGROUND

Lymphaticovenous anastomosis (LVA) is a surgical treatment for lymphedema that requires identification and mapping of functional lymphatic channels. This technique was performed blindly for years because of the lack of suitable methods of study. Progress in imaging techniques and the introduction of Indocyanine green lymphography (ICG-L) represented a significant advancement in lymphedema management. Magnetic resonance lymphangiography (MRL) has also helped improve knowledge about lymphedema anatomy and pathophysiology. We now present our protocol based on both ICG-L and MRL for optimal LVA preoperative planning.

METHODS

A prospective study between April 2010 and June 2015 was conducted in 82 patients (77 females, mean age 45.5 years) with stage I (9.8%), II (73.2%), and III (17.0%) lymphedema. All patients underwent lymphedema surgical treatment with LVA. Surgery was planned based on preoperative information from ICG- L and MRL.

RESULTS

We obtained a mean of 6.87 lymphatic locations per extremity from MRL and selected a mean of 4.04 for LVA. When MRL data coincided with ICG-L data, we found a functional lymphatic vessel in 96.9% of cases and performed LVA successfully in 91.4%.

CONCLUSIONS

ICG-L and MRL are noninvasive techniques that provide images of the lymphatic system with sufficient temporal and spatial resolution to depict functional lymphatic vessels. Such knowledge is essential for preoperative planning of LVA microsurgery. We present our protocol for the approach of surgical treatment of lymphedema. This protocol represents a step forward in unifying patient selection criteria and achieving safe, effective, and rational surgery.

Backpack PCR: A point-of-collection diagnostic platform for the rapid detection of Brugia parasites in mosquitoes

Background

Currently, molecular xenomonitoring efforts for lymphatic filariasis rely on PCR or real-time PCR-based detection of Brugia malayi, Brugia timori and Wuchereria bancrofti in mosquito vectors. Most commonly, extraction of DNA from mosquitoes is performed using silica column-based technologies. However, such extractions are both time consuming and costly, and the diagnostic testing which follows typically requires expensive thermal cyclers or real-time PCR instruments. These expenses present significant challenges for laboratories in many endemic areas. Accordingly, in such locations, there exists a need for inexpensive, equipment-minimizing diagnostic options that can be transported to the field and implemented in minimal resource settings. Here we present a novel diagnostic approach for molecular xenomonitoring of filarial parasites in mosquitoes that uses a rapid, NaOH-based DNA extraction methodology coupled with a portable, battery powered PCR platform and a test strip-based DNA detection assay. While the research reported here serves as a proof-of-concept for the backpack PCR methodology for the detection of filarial parasites in mosquitoes, the platform should be easily adaptable to the detection of W. bancrofti and other mosquito-transmitted pathogens.

Methodology/Principal findings

Through comparisons with standard silica column-based DNA extraction techniques, we evaluated the performance of a rapid, NaOH-based methodology for the extraction of total DNA from pools of parasite-spiked vector mosquitoes. We also compared our novel test strip-based detection assay to real-time PCR and conventional PCR coupled with gel electrophoresis, and demonstrated that this method provides sensitive and genus-specific detection of parasite DNA from extracted mosquito pools. Finally, by comparing laboratory-based thermal cycling with a field-friendly miniaturized PCR approach, we have demonstrated the potential for the point-of-collection-based use of this entire diagnostic platform that is compact enough to fit into a small backpack.

Conclusions/Significance

Because this point-of-collection diagnostic platform eliminates reliance on expensive and bulky instrumentation without compromising sensitivity or specificity of detection, it provides an alternative to cost-prohibitive column-dependent DNA extractions that are typically coupled to detection methodologies requiring advanced laboratory infrastructure. In doing so, this field-ready system should increase the feasibility of molecular xenomonitoring within B. malayi-endemic locations. Of greater importance, this backpack PCR system also provides the proof-of-concept framework for the development of a parallel assay for the detection of W. bancrofti.

Molecular xenomonitoring has demonstrated significant potential as a non-invasive means of providing reliable surveillance for the presence of lymphatic filariasis (LF)-causing parasites. Given the continuing successes of global mass drug administration efforts, the need for such non-invasive surveillance techniques is expanding. However, considering the significant infrastructural demands which such surveillance requires, the development of simplified surveillance methodologies will be fundamental to future programmatic implementation efforts. Accordingly, we have developed a novel, simplified diagnostic platform for point-of-collection-based detection of the LF-causing parasite, Brugia malayi in pools of mosquitoes. By coupling a rapid and inexpensive DNA extraction methodology with a field-friendly amplification platform and test strip-based detection assay, this backpack PCR system eliminates the need for expensive instrumentation and laboratory-based infrastructure. Furthermore, adaptation of the platform described here will allow for the straightforward and rapid development of a parallel assay for the detection of Wuchereria bancrofti, facilitating the increased use of xenomonitoring and enabling mosquito surveillance efforts in regions lacking sophisticated laboratory infrastructure.

Diagnosis and Staging of Lymphedema

Lymphedema often is confused with other causes of extremity edema and enlargement. Understanding the risk factors and physical examination signs of lymphedema can enable the health care practitioner to accurately diagnose patients ∼90% of the time. Confirmatory diagnosis of the disease is made using lymphoscintigraphy. It is important to correctly diagnose patients with lymphedema so that they can be managed appropriately.

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Zusammenfassung. Das Lymphödem ist eine häufige, chronisch fortschreitende und potenziell invalidisierende Erkrankung. In den entwickelten Ländern ist das Extremitätenlymphödem am häufigsten iatrogen nach Krebstherapien erworben. Meist gehören die radikale Lymphadenektomie sowie die Radiotherapie als essenzielle Bestandteile zum Therapiekonzept bei Krebserkrankungen. Diese sind stark assoziiert mit dem Extremitätenlymphödem. Resezierende Verfahren sollten nur im Endstadium der Erkrankung evaluiert werden, wobei die Liposuktion als Ausnahme und weniger invasives resezierendes Verfahren zu einer effektiven Gewebereduktion führen kann. Lymphovenöse Anastomosen und der mikrovaskuläre Lymphknotentransfer haben das experimentelle Stadium verlassen und stellen für ein korrekt auserwähltes Patientenkollektiv echte therapeutische Optionen dar, um die Hautqualität zu verbessern und das Fortschreiten der Erkrankung aufzuhalten. Die Kosten dafür werden zurzeit nur teilweise auf Antrag von den Krankenkassen übernommen. Für Betroffene eröffnen sich mit den mikrochirurgischen Methoden neue Aussichten auf ein besseres Leben. Um das geeignete Patientenkollektiv noch genauer zu definieren und die guten Resultate zu bestätigen, sind prospektive Studien mit höheren Fallzahlen und Langzeitstudien notwendig.

Mucocutaneous manifestations of helminth infections: Nematodes

In the 21st century, despite increased globalization through international travel for business, medical volunteerism, pleasure, and immigration/refugees into the United States, there is little published in the dermatology literature regarding the cutaneous manifestations of helminth infections. Approximately 17% of travelers seek medical care because of cutaneous disorders, many related to infectious etiologies. This review will focus on the cutaneous manifestations of helminth infections and is divided into 2 parts: part I focuses on nematode infections, and part II focuses on trematode and cestode infections. This review highlights the clinical manifestations, transmission, diagnosis, and treatment of helminth infections. Nematodes are roundworms that cause diseases with cutaneous manifestations, such as cutaneous larval migrans, onchocerciasis, filariasis, gnathostomiasis, loiasis, dracunculiasis, strongyloidiasis, ascariasis, streptocerciasis, dirofilariasis, and trichinosis. Tremadotes, also known as flukes, cause schistosomiasis, paragonimiasis, and fascioliasis. Cestodes (tapeworms) are flat, hermaphroditic parasites that cause diseases such as sparganosis, cysticercosis, and echinococcus.

Cell-Free DNA as a Diagnostic Tool for Human Parasitic Infections

Parasites often cause devastating diseases and represent a significant public health and economic burden. More accurate and convenient diagnostic tools are needed in support of parasite control programmes in endemic regions, and for rapid point-of-care diagnosis in nonendemic areas. The detection of cell-free DNA (cfDNA) is a relatively new concept that is being applied in the current armamentarium of diagnostics. Here, we review the application of cfDNA detection with nucleic acid amplification tests for the diagnosis and evaluation of different human parasitic infections and highlight the significant benefits of the approach using non-invasive clinical samples.

Lymphatic filariasis: perspectives on lymphatic remodeling and contractile dysfunction in filarial disease pathogenesis

Lymphatic filariasis, one of the most debilitating diseases associated with the lymphatic system, affects over a hundred million people worldwide and manifests itself in a variety of severe clinical pathologies. The filarial parasites specifically target the lymphatics and impair lymph flow, which is critical for the normal functions of the lymphatic system in maintenance of body fluid balance and physiological interstitial fluid transport. The resultant contractile dysfunction of the lymphatics causes fluid accumulation and lymphedema, one of the major pathologies associated with filarial infection. In this review, we take a closer look at the contractile mechanisms of the lymphatics, its altered functions, and remodeling during an inflammatory state and how it relates to the severe pathogenesis underlying a filarial infection. We further elaborate on the complex host-parasite interactions, and molecular mechanisms contributing to the disease pathogenesis. The overall emphasis is on elucidating some of the emerging concepts and new directions that aim to harness the process of lymphangiogenesis or enhance contractility in a dysfunctional lymphatics, thereby restoring the fluid imbalance and mitigating the pathological conditions of lymphatic filariasis.

Ultrastructure of lymphatic stomata in the tunica vaginalis of humans

Lymphatic stomata are small openings of lymphatic capillaries on the surface of the mesothelium that lines the serous cavity and have the function of active absorption. They play an important role in physiological and pathological conditions. The cavity of the tunica vaginalis is a typical serous cavity of the testis, but the lymphatic stomata of the tunica vaginalis of humans have never been reported. Here, we studied their ultrastructure by scanning and transmission electron microscopy. The submesothelial connective tissue with foramina was investigated after the mesothelial cells were digested using NaOH solution. We found the lymphatic stomata in cuboidal mesothelial cell regions of the parietal layer of the tunica vaginalis of humans with a diameter of about 1-2 μm. Sometimes, closed lymphatic stomata could be observed. Our study is the first to report the existence of lymphatic stomata of the tunica vaginalis of humans. We found that the tunica vaginalis cavity is connected with the lymphatic system through the stomata, which might provide a morphological basis for the drainage of hydrocele and tumor metastasis of the tunica vaginalis of humans.

A robust dry reagent lateral flow assay for diagnosis of active schistosomiasis by detection of Schistosoma circulating anodic antigen

An earlier reported laboratory assay, performed in The Netherlands, to diagnose Schistosoma infections by detection of the parasite antigen CAA in serum was converted to a more user-friendly format with dry reagents. The improved assay requires less equipment and allows storage and worldwide shipping at ambient temperature. Evaluation of the new assay format was carried out by local staff at Ampath Laboratories, South Africa. The lateral flow (LF) based assay utilized fluorescent ultrasensitive up-converting phosphor (UCP) reporter particles, to be read by a portable reader (UPlink) that was also provided to the laboratory. Over a period of 18 months, about 2000 clinical samples were analyzed prospectively in parallel with a routinely carried out CAA-ELISA. LF test results and ELISA data correlated very well at CAA concentrations above 300 pg/mL serum. At lower concentrations the UCP-LF test indicates a better performance than the ELISA. The UCP-LF strips can be stored as a permanent record as the UCP label does not fade. At the end of the 18 months testing period, LF strips were shipped back to The Netherlands where scan results obtained in South Africa were validated with different UCP scanning equipment including a novel, custom developed, small lightweight UCP strip reader (UCP-Quant), well suited for testing in low resource settings.

CONCLUSION

The dry format UCP-LF assay was shown to provide a robust and easy to use format for rapid testing of CAA antigen in serum. It performed at least as good as the ELISA with respect to sensitivity and specificity, and was found to be superior with respect to speed and simplicity of use. Worldwide shipping at ambient temperature of the assay reagents, and the availability of small scanners to analyze the CAA UCP-LF strip, are two major steps towards point-of-care (POC) applications in remote and resource poor environments to accurately identify low (30 pg CAA/mL serum; equivalent to about 10 worm pairs) to heavy Schistosoma infections.

Detection of heartworm infection in dogs via PCR amplification and electrospray ionization mass spectrometry of nucleic acid extracts from whole blood samples

OBJECTIVE

To develop and evaluate a rapid and accurate assay involving PCR amplification and electrospray ionization mass spectrometry of nucleic acid extracts from whole blood samples for the detection of Dirofilaria immitis infection in dogs.

SAMPLE

Whole blood nucleic acid extracts from 29 dogs experimentally infected with D immitis (and in which circulating D immitis antigen was detected) and 10 uninfected dogs.

PROCEDURES

16 of the 29 whole blood samples from infected dogs were examined at the time of collection for circulating microfilaria. Nucleic acids were extracted from all whole blood specimens and underwent PCR amplification with 12 PCR primer pairs designed to detect a wide range of pathogens (including the Wolbachia endosymbiont of D immitis) and electrospray ionization mass spectrometry.

RESULTS

On the basis of assay results, heartworm infection was detected in 13 of 13 antigen-positive dogs of unknown microfilaria status, 11 of 11 antigen-positive dogs with circulating microfilaria, 0 of 3 antigen-positive dogs tested at 3 months after larval infection, 0 of 2 antigen-positive dogs with occult infections, and 0 of 10 uninfected dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

With the assay under investigation, it was possible to identify D immitis infection in dogs with circulating microfilaria via detection of the obligate Wolbachia endosymbiont of D immitis. It was not possible to identify dogs with occult infections, which suggested that circulating microfilaria must be present to detect infection with this assay, although further studies would be required to verify that finding.

Parasitic infections and myositis

Infectious myositis may be caused by a wide variety of bacterial, fungal, viral, and parasitic agents. Parasitic myositis is most commonly a result of trichinosis, cystericercosis, or toxoplasmosis, but other parasites may be involved. A parasitic cause of myositis is suggested by history of residence or travel to endemic area and presence of eosinophilia. The diagnosis of parasitic myositis is suggested by the clinical picture and radiologic imaging, and the etiologic agent is confirmed by parasitologic, serologic, and molecular methods, together with histopathologic examination of tissue biopsies. Therapy is based on the clinical presentation and the underlying pathogen. Drug resistance should be put into consideration in different geographic areas, and it can be avoided through the proper use of anti-parasitic drugs.

Cytological diagnosis of filarial infection in an endemic area where screening and prophylaxis is in place

OBJECTIVE

Filariasis has a worldwide distribution. However, the disease is often overlooked or misdiagnosed because of its unusual presentations and there may be false-negative results in endemic areas. This study was carried out to assess the role of cytology in the demonstration of filarial parasites in an area where screening and prophylaxis are in place.

METHODS

This study was carried out in Wardha district in central India, which is endemic for filarial infection. A total of 9182 smears of cases undergoing cytological evaluation were routinely screened at the time of reporting for the presence of adult filarial worm, microfilarial larvae or their fertilized and unfertilized eggs, irrespective of their original clinical diagnosis.

RESULTS

Microfilariae were found incidentally in fine needle aspiration (FNA) smears of patients presenting with other clinical conditions. Smears of seven cases were found to be positive for microfilaria. Four cases presented with subcutaneous nodules in the upper arm, two cases were seen incidentally in axillary lymph node aspirates and microfilariae were found in the pleural fluid in one case. Another case was suspected to have breast cancer, but aspirates from the axillary area showed lymphatic obstruction considered to be due to filariasis.

CONCLUSION

FNA cytology is an inexpensive, simple and easy procedure for detecting microfilariae. Detection of microfilariae may not be common even in endemic areas as screening and prophylaxis is routinely performed, and patients may show atypical presentations such as subcutaneous nodules. We believe that careful screening of FNAs, especially those from subcutaneous swellings, as well as serous fluids, is very important in a filariasis-endemic zone.