Article Text
Abstract
Human T lymphotropic virus type 1 (HTLV-1) is recognised as an STI with serious manifestations of the disease in approximately 10% of those infected. This case report is the first to describe the short interval from sexual acquisition of HTLV-1 to the onset of HTLV-1-associated myelopathy and rapid progression to spastic paraparesis. The number of adult infections in the UK per annum is unknown, but surveillance data indicate that around 30% of newly diagnosed infections are occurring in persons born in the UK, rather than in migrants from HTLV-1-endemic regions. Despite this, and despite the risk of chronic debilitating disease, HTLV-1 infection is not part of sexual health screening in the UK, with the consequence that patients requesting sexual health screens are not informed of their carrier status and transmission from asymptomatic carriers to the partners will continue.
- HTLV-1
- sexual health
- genitourinary medicine
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Background
Human T lymphotropic virus type 1 (HTLV-1) is a preventable sexually transmittable infection. Although in the majority it is asymptomatic, when it does manifest it causes significant morbidity and mortality. The association of HTLV-1 infection with myelopathy was described in Martinique in 1985 and Japan in 1986 (HTLV-1-associated myelopathy, HAM).1 2 HAM is characterised by slowly progressing weakness and/or spasticity of the lower limbs, bladder, bowel and sexual dysfunction, and pain. ‘Rapid progression’, arbitrarily defined as inability to walk within 2 years of the first symptoms, occurs occasionally.3 4 A 16% reduction in HAM cases in Japan 2 years after the introduction of blood donor HTLV-1 screening suggests that the interval between infection and the disease can be relatively short.5 This interval in non-iatrogenic infection is usually unknown. We describe rapid onset and rapid progression of HAM following sexually acquired HTLV-1 infection in a patient in whom the window of infection is determined, emphasising the rate and severity of disease that may follow this infection. We argue HTLV-1 should no longer be an ignored STI.
Presentation
A previously fit, Caribbean woman developed influenza-like symptoms, backache and lower limb numbness. Five weeks later numbness was ascending to the trunk with dual sphincter involvement. Mobility reduced over the next 2 weeks. Approximately 14 weeks after the first symptoms, she could no longer climb stairs without assistance, and 4 weeks later she was unable to walk due to spastic paraparesis. She had urinary hesitancy and retention as well as constipation. There followed a prolonged inpatient admission.
Investigations
Magnetic resonance scanning showed oedematous cord and extensive signal change from C2 to T10 with patchy enhancement. Cerebrospinal fluid (CSF) contained 0.106 x109/L lymphocytes and 0.01 x109/L polymorphs, a raised protein of 0.66 g/L, normal glucose (CSF glucose 3.3 mmol/L and blood glucose 6.1 mmol/L) and oligoclonal bands. PCR failed to amplify enteroviruses, varicella zoster virus and herpes simplex virus 1 and 2, while HIV, veneral disease research laboratory test (VDRL), antiaquaporin 4 and autoantibody (antinuclear antibodies, double-stranded DNA antibodies, extractable nuclear antigens, antineutrophil cytoplasmic antibodies, cardiolipin antibody, lupus screen) serology and tests for Borrelia, Brucella, Rickettsia, Flavivirus, Alphavirus and Phlebovirus were negative. Serum B12, folate, ferritin, ACE, thyroid-stimulating hormone, immunoglobulins and electrophoresis were unremarkable. HTLV-1/2 antibodies were detected by enzyme immunoassay (sample/cut-off 145) and HTLV-1 infection confirmed by western blot, with antibodies to GD21, p19, p24 and rgp46-1 all strongly positive. Despite high-dose corticosteroids HTLV-1 proviral load was 0.3% in peripheral blood mononuclear cells and 16.2% in CSF, supporting the diagnosis of HAM.
All UK blood donors have been HTLV-1-screened since 2002. As the patient reported a donation 5 months prior to the onset of symptoms, the result was obtained from National Health Service Blood and Transplant. This, and another donation, tested negative for anti-HTLV-1 antibodies at the time of donation and on retest of the archived sera. The patient’s mother tested negative for HTLV-1, but her partner of 2 years tested positive. Sexual intercourse was reported to have taken place once during this period (due to the partner’s ill health).
Discussion
We report a patient with subacute onset of HAM that progressed from the first symptoms to wheelchair dependency over 5 months with dual sphincter involvement and sensory symptoms. This case—to our knowledge the first to report the interval for sexually acquired HTLV-1 infection to the onset of HAM—illustrates a number of important features. First is the short time period between primary HTLV-1 infection and the first symptoms. Second is the rapid onset and progression following sexual transmission of HTLV-1, which has been previously associated with infection through blood transfusion or organ transplantation.6 Third is that HTLV-1 transmission occurred following a single episode of sexual intercourse.
The risk of sexual transmission per coital act is unknown but often perceived to be low. A 5-year longitudinal study of HTLV-1 serodiscordant couples in established relationships identified a 1% risk per annum; however, no studies have examined the risk between serodiscordant couples in new relationships.7 Multiple cross-sectional studies have reported increasing seroprevalence with age, particularly in women, indicating the importance of adult acquisition of HTLV-1. Recent studies from Japan and Brazil suggest that >80% of all prevalent infections have been acquired during adult life.8 The number of adult infections in the UK per annum is unknown, but surveillance data indicate that around 30% of newly diagnosed infections are occurring in persons born in the UK, rather than in migrants from HTLV-1-endemic regions.9 Despite this, and despite the risk of chronic debilitating disease, HTLV-1 infection is not part of sexual health screening in the UK, with the consequence that patients requesting sexual health screens are not informed of their carrier status and transmission from asymptomatic carriers to the partners will continue.
Key messages
Human T lymphotropic virus type 1 (HTLV-1) is an STI where condoms reduce transmission risk.
HTLV-1 antibody tests that are highly sensitive and specific are readily available in the UK.
When HTLV-1 is symptomatic it is associated with significant morbidity and mortality.
Footnotes
Handling editor Anna Maria Geretti
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; internally peer reviewed.