The “Silent Pandemic: HTLV-1 Virus and its Impact on Public Health”

Vicente Soriano, Vice Dean of Research of the Faculty of Health of the International University of La Rioja (UNIR)

Vicente Soriano is Vice Dean of Research at the Faculty of Health of the International University of La Rioja (UNIR) and a specialist in infectious diseases. The doctor is the master of ceremonies for an event organized by the Madrid College of Physicians (ICOMEM) on September 15 regarding the HTLV-1 virus, branded as the protagonist of a “silent pandemic” because it is hardly tracked and sought , even though its symptoms can be very severe.

It is a rare disease with little spread in Europe, but with the globalization of the 21st century it has already had small incidences in the country. Spain is one of the few countries in the world with a national count of cases and has barely reached 500 since 1989, the year in which monitoring began. However, the scientific community is practically convinced that there are many more cases that are not detected, since the number of asymptomatic patients is 90% and, therefore, they are mere carriers of the virus.

Question: What characteristics does this virus have?

Answer: There are two types of viruses, those that have DNA or RNA of genetic material. RNAs are the protagonists of the pandemics of the last fifty years: the AIDS virus, Hepatitis C, Ebola or Sars (the covid virus). The AIDS virus appeared in 1981, but HTLV-1 had already been described two years earlier, hence that one in its name. AIDS is HTLV-3. The media impact took everything from HIV, but this is a virus that has been in the human species for a long time.

Q: What symptoms does HTLV-1 cause?

It produces two diseases: a T-leukemia, which is the rarest and has a very poor prognosis since most of the people diagnosed die; the other disease is myelopathy, which consists of losing the strength of the lower extremities. HTLV-1 previously occurred in the tropics, in sub-Saharan Africa, and in Latin America. There it is known as tropical spastic paraparesis.

It is transmitted like the AIDS virus, by sexual transmission, by transfusions or from mothers to children during lactation. In Europe we had no cases, but with the migratory movements of the 21st century some cases have already appeared. In Spain we have about 20 cases diagnosed each year, but we call it a silent pandemic because there are many cases that are not diagnosed, since 90% are asymptomatic. Unlike the HIV virus, which develops AIDS after ten years, not with this disease. Only 10% of infected people develop symptoms, either blood cancer or paralysis. The other 90% die with the virus, but not from the virus. They are carriers. Since they do not know they are infected, they can transmit it to others.

The HTLV-1 virus (CDC, Wikimedia Commons).

Q: Is it detectable? What’s wrong?

It can be detected, but one of the conclusions we have is that it is convenient to include it in the antinatal tests or in those for sexual transmission screening, which is currently not available. It is not there because there is no awareness that it is a virus that is transmitted sexually. We are at that stage, making doctors and public administrations aware that it is very cheap to have it controlled.

But another big issue is that there is no vaccine or drugs. For AIDS and hepatitis we already have things, but for this, the only prevention mechanism is to avoid risk exposure. Those who develop leukemia are usually prescribed monoclonal antibodies, but they have a poor prognosis and we try a bone marrow transplant, which is a risky intervention. For sexual or maternal-fetal prevention, HIV anti-fat inhibitors such as Cabotegravir are used experimentally, but in the absence of a clinical trial, the results are poor.

Q: Is the mortality rate of this disease high?

A: The mortality rate of T-leukemia is more than 80% after three years. Myelopathy does not cause death, but those who suffer from it end up in wheelchairs and cause autoimmune diseases. Spain is one of the only countries with a national registry of cases since 1989. In other countries there are, but not national ones. We have close to 500 accumulated cases since then.

Q: Are the cases that are identified because they have generated symptoms?

A: There is a large proportion of registered cases that is because they have developed symptoms, but when we screen relatives we find some others infected. Also in blood banks, because in Madrid, Catalonia and other communities they do look for HTLV-1 to donate blood and diagnoses are found there.

2023-09-08 03:00:13
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