Human T‐cell lymphotropic virus‐1 (HTLV‐1)

• The World Health Organisation (WHO) will convene a Guideline Development Group (GDG) for the development of evidence-based recommendations on Human T‐cell lymphotropic virus-1 (HTLV-1) in December.

• The objective of this meeting will be to provide recommendations and guidance on HTLV‑1 testing and prevention, addressing who to test, how to test, resource use and broader prevention approaches.

• This is the first guideline to incorporate the latest evidence and good practices on addressing testing for and prevention of HTLV‑1. 

• It will feed into a larger process of setting priorities and principles for HTLV‑1 testing and prevention and stimulate the development of a public health response. 

• In accordance with WHO guidelines for developing recommendations, the GDG is composed of members from all WHO regions, serving in their individual capacities rather than as representatives of affiliated organisations. 

Human T‐cell lymphotropic virus‐1 (HTLV‐1)

• Human T‐cell lymphotropic virus‐1 (HTLV‐1) is the first human retrovirus to be identified. 

• It was originally detected in 1977 from a patient with skin T‐cell lymphoma and a patient with a newly described condition, adult T‐cell leukaemia. 

• HTLV‑1 affects at least 5-10 million people globally. 

• It is concentrated in western and central Africa, Latin America, and the Western Pacific Region. 

• HTLV-1 is primarily transmitted through breast feeding, sexual contact,  needle sharing and unsafe blood transfusion.

• This neglected sexually transmitted infection (STI) causes an aggressive malignancy of the blood and blood-forming organs, known as adult T-cell leukaemia/lymphoma (ATL). 

• HTLV-1 also causes a progressive neurological condition known as HTLV-1-associated myelopathy or tropical spastic paraparesis (HAM/TSP). 

• Serological studies show that infection with HTLV‐1 is endemic in some countries and rare in others, with considerable intraregional variation. 

• There is currently no vaccine for HTLV-1.

• There is no effective treatment for HTLV-1 and emphasis is placed on detection and prevention. 

• Most high-income countries have introduced HTLV-1 screening of blood donations, but few public health measures have been implemented. 

• More concerted global public health actions are needed to contain this infectious disease.

• Controlling transmission of HTLV-1 infections can reduce the disease burden. HTLV-1 prevention can be integrated into blood safety, sexually transmitted infection services, and prevention of mother-to-child infection in prevalent settings.