Symptoms:

Initial symptoms are subtle and include gait problems, unexplained falls, lower back pain, constipation, urinary urgency/incontinence, and numbness or pain in the lower limbs. Over the years, progressive leg weakness ensues, followed by the worsening of the urinary and sensory symptoms. 

Diagnosis:

Samples are initially screened by enzyme immunoassay (EIA), and negative results indicate provisional virus-free status. Positive results are further tested by confirmatory Western blot analysis and reactive animals are slaughtered or removed from the colony..

Cause:

In the Americas, HTLV-1 has more than one origin: introduced by Paleolithic immigrants through the Bering Strait, through the colonial slave trade, and by Japanese immigration in the early 20th century. At the same time, HTLV-2 was an immigrant only through Bering Strait.

Treatment:

Potential treatments include prosultiamine, a vitamin B-1 derivative; azacytidine, an anti-metabolite; tenofovir disoproxil (TDF), a reverse-transcriptase inhibitor used for HIV; cepharanthine, an alkaloid from Stephania parantha Hayata; and phosphonate carbocyclic 2'-oxa-3'aza nucleosides (PCOANs). A newer formulation of TDF called tenofovir alafenamide (TAF) also has promise as a treatment with less toxicity.