More than 10 million people unknowingly carry the virus HTLV-1

HTLV-1: A virus continues to spread unnoticed

Millions of people worldwide are already infected with HTLV-1, a human virus that is primarily transmitted during sex and causes a specific form of leukemia (blood cancer). In addition, the virus is associated with various other diseases. But hardly anyone knows HTLV-1 (human T-lymphotropic virus 1) and the dangers that emanate from it. Although the virus was discovered decades ago, research has only recently returned to this topic. A vaccine or cure is not yet possible.

In a letter to the World Health Organization (WHO), scientists have now called for increased attention for HTLV-1 infections. More than ten million people around the world are already infected with the virus and most are unaware of their infection, reports the research team led by Charles Bangham of Imperial College London. In a recent study, British experts investigated the effects of HTLV-1 on the human genome, with worrying results. The study was published in the journal "eLife".

90 percent of those affected know nothing about their infection

The fact that millions of people are unknowingly infected with a virus that can in the worst case trigger fatal diseases and is transmitted during sexual intercourse is strongly reminiscent of the initial situation in HIV. "Humans have been able to carry the virus without symptoms for decades, and 90 percent of those affected do not know they're in it," say scientists at Imperial College London. The virus can also be transmitted by blood transfusions and breast milk, but usually the infection occurs through unprotected sexual intercourse. An estimated five to ten percent of those infected develop an aggressive form of leukemia or progressive paralytic disease as a result of the infection.

Research on HTLV-1 neglected for years

The discovery of HTLV-1 in 1980 by a research group led by Robert Gallo at the NIH was a sensation at the time. For decades, researchers had been looking for retroviruses in humans and now finally had the proof that these exist. However, the AIDS virus HIV was also discovered shortly thereafter, and in view of the enormous health threat posed by HIV, research in the coming decades focused on this type of retrovirus. HTLV-1 was neglected. A mistake, so the assessment of the doctors today.

Substantial interference with the genome

What far-reaching consequences the viruses can have on the genome of the infected have been proven by British scientists at Imperial College London in their latest study. The researchers explain that viruses such as HTLV-1 have the potential to destroy tens of thousands of genes due to the large number of so-called CTCF sites in the human genome. The new findings are also a possible explanation for the link with leukemia and other diseases.

Connection with lung diseases

Bronchiectasis (bronchial outgrowth) is one of the diseases that can cause HTLV-1, according to an Australian study published in March of this year. The study was carried out on indigenous Australians, who had previously reported relatively high infection rates with HTLV-1 in a previous study. The scientists examined possible associations of viruses with lung disease such as bronchiectasis, bronchitis and bronchiolitis. The influence of viruses on the risk of death was also determined.

Risk underestimated so far?

According to the study authors, the viruses are associated with airway inflammation and premature death due to complications of bronchiectasis. "Our findings suggest that mortality associated with HTLV-1c infection may be higher than previously thought," the researchers warn. Further studies on the risks of HTLV-1 infections are now required. (Fp)