A case of visceral leishmaniasis found by left oblique hernia: A case report

Long-term hematopoietic stem cells as a parasite niche during treatment failure in visceral leishmaniasis

Given the discontinuation of various first-line drugs for visceral leishmaniasis (VL), large-scale in vivo drug screening, establishment of a relapse model in rodents, immunophenotyping, and transcriptomics were combined to study persistent infections and therapeutic failure. Double bioluminescent/fluorescent Leishmania infantum and L. donovani reporter lines enabled the identification of long-term hematopoietic stem cells (LT-HSC) as a niche in the bone marrow with remarkably high parasite burdens, a feature confirmed for human hematopoietic stem cells (hHSPC). LT-HSC are more tolerant to antileishmanial drug action and serve as source of relapse. A unique transcriptional ’StemLeish’ signature in these cells was defined by upregulated TNF/NF-κB and RGS1/TGF-β/SMAD/SKIL signaling, and a downregulated oxidative burst. Cross-species analyses demonstrated significant overlap with human VL and HIV co-infected blood transcriptomes. In summary, the identification of LT-HSC as a drug- and oxidative stress-resistant niche, undergoing a conserved transcriptional reprogramming underlying Leishmania persistence and treatment failure, may open therapeutic avenues for leishmaniasis.

Long-term hematopoietic stem cells may act as protective niches for the Leishmania parasite, potentially contributing to treatment failure in cases of visceral leishmaniasis.

A case of inguinal hernia associated with atypical Dirofilaria repens infection in a dog

BACKGROUND

Dirofilaria repens is a filarioid nematode transmitted by mosquitoes. Adult D. repens are typically localized in the subcutaneous tissue of the host, but other, atypical localizations have also been reported. There have been several reports of clinical cases involving an association of parasites and hernias in both animals and humans. However, it is unclear if parasitic infection can act as a triggering factor in the development of hernias.

METHODS

A 12-year-old dog was referred to a private veterinarian clinic in Satu Mare, northwestern Romania due to the presence of a swelling in the lateral side of the penis (inguinal area). The dog underwent hernia repair surgery during which four long nematodes were detected in the peritoneal serosa of the inguinal hernial sac. One female specimen was subjected to genomic DNA extraction to confirm species identification, based on amplification and sequencing of a 670-bp fragment of the cytochrome c oxidase subunit 1 (cox1) gene. Treatment with a single dose of imidacloprid 10% + moxidectin 2.5% (Advocate, Bayer AG) was administered.

RESULTS

The nematodes were morphologically identified as adult D. repens, and the BLAST analyses revealed a 100% nucleotide similarity to a D. repens sequence isolated from a human case in Czech Republic.

CONCLUSIONS

We report a case of an atypical localization of D. repens in the peritoneal cavity of a naturally infected pet dog with inguinal hernia and discuss the associations between hernia and parasitic infections.

Utility of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients with Visceral Leishmaniasis: Case Report and Literature Review

The diagnosis of visceral leishmaniasis (VL) is complicated and often unsuspected. Little is known of the usefulness of nuclear imaging in VL. Our objective was to describe findings seen in fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in cases of VL. We retrospectively reviewed VL cases diagnosed at Vall d'Hebron University Hospital from May 2012 to May 2018 and selected those that had an FDG-PET/CT performed. Information on procedures and details of the FDG-PET/CT features and follow-up were collected. We then systematically reviewed the literature on VL and FDG-PET/CT. Four of 43 patients diagnosed with VL had an FDG-PET/CT performed. All four patients presented diffuse splenic uptake of FDG-PET/CT. Adenopathy was not always present, and bone marrow uptake was found in two patients. A posttreatment FDG-PET/CT in one patient revealed normalization of initial findings. In the literature review, 43 of 50 cases presented similar splenic uptake in the PET/CT, being described as different patterns: "increased metabolism," "homogeneous," "diffuse," "diffuse and multifocal," "nodular," "patchy and granular," "subcortical," and "compatible with lymphoma." Other frequent findings were bone marrow uptake and adenopathies. We, therefore, conclude that FDG-PET/CT could become a useful tool for the diagnosis and follow-up of VL and that VL should be taken into account in patients with fever of unknown origin with enhanced splenic uptake in FDG-PET/CT. Differential diagnosis in these cases should be made with splenic primary lymphoma, virus infections, chemotherapy, and colony-stimulating factor therapy. Further structured studies with more cases are needed to define its diagnostic and prognostic value.