Extraction of nucleic acids from ancient formalin- and ethanol-preserved specimens of the tapeworm Bertiella studeri: which method works best?

Comprehensive Diagnosis, Treatment, and Outcome of Taenia crassiceps Cysticercosis in a Ring-Tailed Lemur (Lemur catta) from a Croatian Zoo: No Longer Unusual?

Taenia crassiceps is a zoonotic tapeworm of the genus Taenia that is distributed throughout the Northern Hemisphere. Wild and domestic carnivores are final hosts, while rodents and rabbits are primarily intermediate hosts, although many other mammals may harbour the larval stage, Cysticercus longicollis. This case report aims to describe C. longicollis infection in a lemur and molecularly characterise the isolated parasite. The excised lesion was subjected to morphological and histopathological examination, which revealed cysticerci of the tapeworm. Formalin-fixed and paraffin-embedded block (FFPEB), as well as the cysticerci fixed with formalin stored for one year, were subjected to molecular analysis, which aimed at detecting the partial mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of Taenia sp. Based on the morphological characteristics, the parasite was identified as a metacestode of T. crassiceps. The presence of the cox1 gene was detected using polymerase chain reaction (PCR) in all samples. A randomly selected PCR product was sequenced and compared with other sequences from the GenBank database, confirming that the detected parasite was T. crassiceps. This article reports the first case of T. crassiceps cysticercosis in a lemur (Lemur catta) in Croatia and emphasises the potential risk of transmission from wild carnivores.

A retrospective study of Taenia spp. in Cuban patients: what does molecular analysis tell us?

Taeniosis is a neglected disease, particularly in developing countries, and is caused by infection with the adult tapeworm of either Taenia solium, Taenia saginata, and Taenia asiatica. Of these, T. solium is of primary concern due to the potential for cysticercosis should T. solium eggs be ingested. In Cuba, all cases of taeniosis are assumed to be caused by T. saginata, although some cases of cysticercosis have been documented. It is therefore important to gain further insights regarding the species causing taeniosis in Cuba, especially as diagnostic records indicate an increasing incidence, with the highest number of cases reported in 2020. In this study, we analysed 37 Taenia-positive faecal samples (or proglottids isolated from faecal samples) from the period 2001 until 2020 from all regions of the country. Genomic DNA was extracted from the samples, which had been stored in 10% formalin, using the QIAamp Tissue Kit. Species identification was carried out by duplex real-time PCR targeting the mitochondrial DNA. All cases were found to be T. saginata, and sequence analysis of three isolates confirmed the identification of this species. Our data do not provide any evidence that T. solium currently occurs in Cuba. However, given the relatively low number of samples analysed here, that the parasite may be imported with visitors or travellers who have been in endemic countries, and that taeniosis has relatively mild symptoms and thus infected patients may not seek medical attention, we recommend species determination for all taeniosis cases reported in Cuba.

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The incidence of taeniosis cases in Cuba is rising, with 2020 being a peak year

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Although assumed to be Taenia saginata, this has not been confirmed

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We investigated 37 samples from 2001 until 2020 that had been stored in formalin

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Duplex real-time PCR indicated T. saginata; 3 cases were confirmed by sequencing

Molecular Analysis of Dirofilaria repens Isolates from Eye-Care Patients in Greece

PURPOSE

Human ocular dirofilariasis is a zoonotic disease caused by several species of filarioid helminths of the genus Dirofilaria. The aim of this study was to further re-examine five preserved specimens previously isolated from patients with ocular dirofilariasis by molecular means.

METHODS

Four of the examined helminths had been stored in unbuffered formaldehyde solution for more than eight years; whereas, the fifth helminth was stored in ethanol buffer for more than two years. For the four specimens stored in formaldehyde, different methods of DNA recovery and amplification were applied and investigated for their efficiency in DNA extraction and PCR amplification. However, the DNA extraction and PCR amplification were successful only for the ethanol-preserved helminth.

RESULTS

The genetic identification of the ethanol-preserved specimen as Dirofilaria repens (D. repens) and its phylogenetic position based on the analysis of mitochondrial 12S ribosomal RNA, nuclear 18S ribosomal RNA and mitochondrial cytochrome c oxidase subunit one sequences are reported in the present paper. To our knowledge, these are the only deposited sequences related to D. repens that have been isolated in Greece.

CONCLUSIONS

Routine laboratory diagnosis is based on phenotypic characteristics of the helminthic parasites, but more accurate diagnosis requires molecular identification. Although the specimens preserved in formalin buffers may be a potential source for the enrichment of parasite genome databases, the DNA recovery of such samples is a challenging task.

Comparable cytological features between cells processed as either wet mount or conventional cytospins

OBJECTIVE

Microfluidics represents a novel approach for the processing of pathological biopsy specimens. It represents an enabling platform between traditional morphology-driven pathology diagnostics and future sequencing technologies. Microfluidics requires the dissociation of cells from tissue, but the evaluation of these cells still lies within the domain of pathology, specifically cytopathology. The dissociated cells, however, require supravital staining and examination under wet mount conditions as part of their processing in a microfluidic platform. These conditions are vastly different from current approaches for cytopathological specimen preparation. No studies to date have compared the cytological characteristics of cells between these two different conditions.

METHODS

Slivers of different types of unfixed tissue were procured and the cells were dissociated. The cells were recovered and separated for processing either by staining with a supravital dye and examination under wet mount conditions or by conventional preparatory methods and staining by the Papanicolaou method.

RESULTS

Obvious differences existed in the tinctorial hue between similar cells stained by the two different methods; however, there were no significant differences in the features between the matched cells. Some cells in the wet mount preparations existed in three-dimensional balls, reducing the quality of the images relative to cells flattened to the slide by the cytospin method.

CONCLUSIONS

Cells stained with a supravital stain and examined in a wet mount environment appear to be cytologically similar to cells prepared by conventional methods. Long-established criteria for the evaluation of cells prepared by established protocols can therefore be extended and applied to cells viewed within a microfluidic platform.