[Combined infection with HTLV-1 and Strongyloides stercoralis]

A Textbook Case of Human T-lymphotropic Virus-1 (HTLV-1)-Induced Adult T-cell Leukemia Treated With Cyclophosphamide, Hydroxydaunorubicin, Oncovin, and Prednisone/Prednisolone (CHOP)

Human T-lymphotropic virus-1 (HTLV-I) is an enveloped, single-stranded RNA virus of the Retroviridae family. The virus causes two well-recognized disease associations: adult T-cell leukemia/lymphoma (ATL) and HTLV-I-associated myelopathy (HAM), also known as tropical spastic paraparesis (TSP). We report a case of HTLV-1-induced adult T-cell lymphoma/leukemia in a 45-year-old female who presented with complaints of swelling on the right side of her neck and rash on her upper and lower extremities and abdomen. The patient also had a history of strongyloidiasis infection and Crohn's disease. She was found to have hypercalcemia and multiple lytic lesions of the bone found on the imaging. She also tested positive for HTLV-1 and T cell-positive for cluster of differentiation (CD) 2, CD3, partial CD5, and minimal CD56, later confirmed by the bone marrow (BM) and skin punch biopsies. ATL is characterized by the clonal proliferation of CD4+ T cells containing randomly integrated HTLV-I provirus, often associated with T-cell receptor gene rearrangements. ATL, in its aggressive forms, has one of the poorest prognoses of non-Hodgkin lymphoma. It is essential to raise awareness of ATL, although further research and trials are needed to solidify the treatment options to prevent mortality.

Evaluation of Strongyloides stercoralis infection in patients with HTLV-1

INTRODUCTION

Individuals infected with the human T-lymphotropic virus type 1 (HTLV-1) may present severe and disseminated forms of Strongyloides stercoralis infection with low therapeutic response.

OBJECTIVE

To investigate the S. stercoralis infection and the seroprevalence of IgG anti-S. stercoralis antibodies in individuals infected with HTLV-1 attending the Reference Center for HTLV-1 (CHTLV) in Salvador, Bahia, Brazil.

MATERIALS AND METHODS

We conducted a cross-sectional study in 178 HTLV-1-infected individuals treated at the HTLV specialized center between January, 2014, and December, 2018. The parasitological diagnosis of S. stercoralis was performed using the Hoffman, Pons and Janer, agar plate culture, and Baermann-Morais methods. The IgG anti-S. stercoralis detection was performed using an in house enzyme-linked immunosorbent assay (ELISA). The HTLV-1 infection was diagnosed using a commercial ELISA and confirmed by Western blot.

RESULTS

The frequency of S. stercoralis infection was 3.4% (6/178). Individuals infected with S. stercoralis from rural areas (50.0%; 3/6) also showed S. stercoralis hyperinfection (>3,000 larvae/gram of feces). The frequency of circulating anti-S. stercoralis IgG antibodies was 20.8% (37/178).

CONCLUSIONS

HTLV-1-infected people living in precarious sanitary conditions are more prone to develop severe forms of S. stercoralis infection. Considering the high susceptibility and unfavorable outcome of the infection in these individuals, the serological diagnosis for S. stercoralis should be considered when providing treatment.

A PCR-Based Molecular Detection of Strongyloides stercoralisin Human Stool Samples from Tabriz City, Iran

Strongyloides stercoralis is a nematode causing serious infections in immunocompromised patients. In chronically infected patients, the low parasitic content as well as the resemblance of the larvae to several other species make diagnosis basedonmorphology difficult. In the present study, a PCR-based method targeting the internal transcribed sequence 2 (ITS2) of the rDNA region was examined for the molecular detection of S. stercoralis infection from the stool samples. A total of 1800 patients were included. Three fresh stool samples were collected per patient, and S. stercoralis isolates were identified by the morphological method. A subset of isolates was later used in the PCR-based method as positive controls. Additionally, negative and no-template controls were included. Data analysis was accomplished using an x² test. Ap-value less than 0.05 was considered significant. In total, fivestool samples were found to be infected with S. stercoralis using the morphology method. PCR method detected S. stercoralis DNA target from all of the fiveDNA samples extracted from positive fecal samples. Conclusions: The PCR method used for amplifying a short fragment was successful for diagnosis of S. stercoralis in fecal samples and can be reliable for directly detecting the parasite bypassing morphological method.

Prevalence of Strongyloides stercoralis and other intestinal parasitic infections among mentally retarded residents in central institution of southern Iran

OBJECTIVE

To determine the prevalence of intestinal parasitic infections among mentally retarded residents of rehabilitation center of Bandar Abbas, Hormozgan province, southern Iran.

METHODS

A cross-sectional study was carried out in central rehabilitation institute of Hormozgan province in summer 2010. Fecal samples of all 133 residents (72 males, 61 females) aged 3-52, were collected in triplicate. Specimens were examined by direct smear, formalin-ether concentration techniques and stained by permanent Trichrome, Ziehl-Neelsen stains. Statistical analysis was conducted by SPSS 13.5.

RESULTS

Intestinal parasitic infections were seen in 48.5% (64 out of 133 subjects: 53.4% in males and 46.6% in females). Strongyloides stercoralis with 17.3% showed the highest incidence followed by Entamoeba coli (9.8%), Blastocystis hominis (7.5%), Giardia lamblia (2.3%), Endolimax nana (2.3%), Hymenolepis nana (0.8%), Oxyuris vermicularis (0.8%), and Chilomasix mesnili (0.8%). Double infections were found to be as: Strongyloides stercoralis + Giardia lamblia (2.3%), Entamoeba coli + Giardia lamblia (1.5%), Entamoeba coli + Blastocystis hominis (1.5%), Oxyuris vermicularis + Entamoeba coli (0.8%), Strongyloides stercoralis + Entamoeba coli (0.8%), respectively.

CONCLUSIONS

Our findings reveal that strongyloidiasis is a common disease among mentally retarded population in southern Iran.

Strongyloides stercoralis infection in marmosets: replication of complicated and uncomplicated human disease and parasite biology

BACKGROUND

Strongyloides stercoralis can undergo an alternative autoinfective life cycle in the host, which, in some individuals can lead to a lethal infection. However, due to a number of factors, such as, the majority of those infected are from low-income backgrounds and the limitation in experimental models for studying human S. stercoralis, strongyloidiasis remains neglected. Improved knowledge of animal models that are susceptible to this parasite is needed in order to investigate the immunological mechanisms involved during infection and in particular to further understand the natural history of the autoinfective cycle.

METHODS

Callithrix penicillata were inoculated subcutaneously with 100 (n = 2), 300 (n = 4) or 500 (n = 9) third-stage infective larvae (L3i) of S. stercoralis of human origin. Three marmosets received smaller inocula (i.e., one received 100 and two received 300 L3i) to ensure a greater capacity to withstand the infection after immunosuppression, which was triggered by administration of dexamethasone during early patency. Qualitative faecal analyses began at 7 days post-infection (DPI), and semi-quantitative tests were also performed for the dexamethasone-treated primates and the three matched controls. During the necropsies, specimens of S. stercoralis were recovered and tissue fragments were processed for histopathology.

RESULTS

The mean prepatency and patency periods were 16.1 ± 3.0 and 161.1 ± 72.2 DPI, respectively. The marmosets typically tolerated the infection well, but immunosuppressed individuals exhibited higher numbers of larvae in the faeces and progressive clinical deterioration with late disseminated infection. In these cases, the number of females recovered was significantly higher than the number of inoculated L3i. Large quantities of larvae were observed migrating through the host tissues, and histopathology revealed pulmonary and intestinal injuries consistent with those observed in human strongyloidiasis.

CONCLUSIONS

Both complicated and uncomplicated strongyloidiasis occur in C. penicillata that is described as a susceptible small non-human primate model for S. stercoralis. This host permits the maintenance of a human strain of the parasite in the laboratory and can be useful for experimental investigations of strongyloidiasis. In parallel, we discuss data related to the autoinfective cycle that provides new insights into the biology of S. stercoralis.

Development of a rapid serological assay for the diagnosis of strongyloidiasis using a novel diffraction-based biosensor technology

BACKGROUND

Strongyloidiasis is a persistent human parasitic infection caused by the intestinal nematode, Strongyloides stercoralis. The parasite has a world-wide distribution, particularly in tropical and subtropical regions with poor sanitary conditions. Since individuals with strongyloidiasis are typically asymptomatic, the infection can persist for decades without detection. Problems arise when individuals with unrecognized S. stercoralis infection are immunosuppressed, which can lead to hyper-infection syndrome and disseminated disease with an associated high mortality if untreated. Therefore a rapid, sensitive and easy to use method of diagnosing Strongyloides infection may improve the clinical management of this disease.

METHODOLOGY/PRINCIPAL FINDINGS

An immunological assay for diagnosing strongyloidiasis was developed on a novel diffraction-based optical bionsensor technology. The test employs a 31-kDa recombinant antigen called NIE derived from Strongyloides stercoralis L3-stage larvae. Assay performance was tested using retrospectively collected sera from patients with parasitologically confirmed strongyloidiasis and control sera from healthy individuals or those with other parasitoses including schistosomiasis, trichinosis, echinococcosis or amebiasis who were seronegative using the NIE ELISA assay. If we consider the control group as the true negative group, the assay readily differentiated S. stercoralis-infected patients from controls detecting 96.3% of the positive cases, and with no cross reactivity observed in the control group These results were in excellent agreement (κ = 0.98) with results obtained by an NIE-based enzyme-linked immunosorbent assay (ELISA). A further 44 sera from patients with suspected S. stercoralis infection were analyzed and showed 91% agreement with the NIE ELISA.

CONCLUSIONS/SIGNIFICANCE

In summary, this test provides high sensitivity detection of serum IgG against the NIE Strongyloides antigen. The assay is easy to perform and provides results in less than 30 minutes, making this platform amenable to rapid near-patient screening with minimal technical expertise.

HTLV-I infection in the South West Indian Ocean islands, particularly in La Réunion and the Seychelles

Data on HTLV-I are scarce in several Southwest Indian Ocean islands except for La Réunion and The Seychelles. The two cases of HTLV-I have been confirmed by Western-Blot in La Réunion, among blood donors. In Seychelles (87 400 inhabitants in 2012), where blood donors and some other cases are screened, HTLV-I was confirmed with a line immune assay in 43 persons and at least 10-20 patients are known to have tropical spastic paraparesia or adult T-cell lymphoma associated with HTLV-I. In the south-west Indian Ocean, a possibly important other issue may be co-infection of HTLV-1 with the Strongyloides stercoralis roundworm, which is endemic in all countries of the region and which can sometimes lead to severe symptomatic infestation.