5/05/2018 HTLV‐1 for health practitioners
HTLV‐1 for health practitioners
What is HTLV‐1?
HTLV‐1 is the short name for ‘Human T‐cell lymphotropic virus type 1’. It is a virus that infects a type of white blood cell called a T‐
lymphocyte. HTLV‐1 is a distant relative of the human immunodeficiency viruses (HIV) which can cause acquired immunodeficiency syndrome (AIDS). HTLV‐1 does not cause AIDS.
Transmission
HTLV‐1 can be transmitted through unprotected sex, by sharing contaminated needles, by blood transfusion and from mother to child (primarily through prolonged breast feeding).
Overseas studies found that the overall risk of transmission by breast feeding is 20%, but risk increases from around 5% at 6 months to more than 30% if infants are breast fed longer than 12 months. Few infants are infected before or during birth.
HTLV‐1 cannot be transmitted through social contact with infected people such as hand shaking, hugging, kissing or drinking from the same glass, nor can it be transmitted by coughing.
Prevalence
HTLV‐1 is prevalent in many countries, principally Japan, the Caribbean and central Africa. It is also found in Iran, Iraq, southern India, China, the Seychelles, Papua New Guinea, the Solomon Islands and Australia.
In Australia, the virus has been found in many Aboriginal populations in Central Australia as well as the Kimberley.
In Central Australia the adult prevalence in the Aboriginal population approaches 50% in some communities. Prevalence is much lower in the Top End and close to zero in East
Arnhem Land. In non‐Aboriginal Australians the virus still appears to be extremely uncommon but sporadic cases have been reported.
Diagnosis
The diagnosis is made by the detection of antibodies to HTLV‐1 in a blood test followed up by more specific confirmatory tests.
What diseases does HTLV‐1 cause?
The majority of HTLV‐1 infected individuals will remain asymptomatic.
Two diseases have been definitely associated with HTLV‐1:
1. A type of cancer which affects the blood or lymph glands—called adult T‐cell leukaemia/lymphoma (ATLL)
2. A disease of the spinal cord which causes weakness similar to multiple sclerosis—
HTLV‐1 associated myelopathy/tropical spastic paraparesis (HAM/TSP).
Only a small proportion of HTLV‐1 carriers will actually develop these 2 diseases. ATLL has been estimated to occur in up to 5% of persons infected with HTLV‐1 and usually presents later in life, with the peak incidence after 50 years of age. HAM/TSP develops in 0.25%—3% of HTLV‐1 infected persons.
Other inflammatory diseases linked to HTLV‐1 infection include: chronic lung diseases, eye inflammation and infective dermatitis.
HTLV‐1 infection also predisposes to more severe infections with other pathogens, such as strongyloidiasis and scabies.
Treatment
No specific treatment is available that targets the HTLV‐1 virus but treatment is available for complications. New treatments for ATLL are moderately effective.
5/05/2018 HTLV‐1 for health practitioners
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Immunosuppressive therapy for HTLV‐1 associated inflammatory disorders can be effective if treatment is started before there is significant tissue injury, and infective
dermatitis responds to topical steroids and long‐term antibiotics.
Prevention of infection
Transmission by breast milk can be prevented by bottle feeding or freeze‐thawing breast milk from infected mothers. Strategies to reduce risk of transmission to infants should be discussed with a physician experienced in the management of HTLV‐1 infection.
Persons infected with HTLV‐1 should refrain from donating blood, semen, body organs, or other tissues.
In January 1993, the Australian Red Cross instituted universal screening of all blood donations for HTLV‐1.
Safer sex practices are always recommended and HTLV‐1 infected persons should be educated that this virus can be transmitted sexually and to use condoms to help prevent transmission to a negative partner. Couples desiring pregnancy should be made aware of
the finite risk of sexual transmission of HTLV‐1 during attempts at pregnancy.
As for all patient contact, universal precautions are recommended to guard against HTLV‐1 transmission to health‐care workers.
The risk of occupational transmission is low;
however, health‐care workers caring for HTLV‐1 infected persons need to avoid percutaneous exposure to HTLV‐1
contaminated blood, as counselled for other blood borne viruses. In view of a higher prevalence of HTLV‐1 in some inland Aboriginal populations, HTLV‐1 antibodies should be tested at baseline when needle‐stick incidents are reported and during follow‐up according to protocol.
To date there have been no studies of using anti‐HIV drugs to prevent transmission of HTLV‐1 and there is currently no vaccine available.
Infection with HTLV‐1 is a notifiable condition in the NT as are the 2 uncommon diseases that are clearly associated with HTLV‐1 infection:
ATLL and HAM/TSP
.
For more information contact the Centre for Disease Control in your region
Alice Springs 8951 7540 Darwin 8922 8044 Katherine 8973 9049 Nhulunbuy 8987 0357 Tennant Creek 8962 4259
or
https://health.nt.gov.au/professionals/centre‐for‐disease‐control/cdc‐contacts
