Last update Jan. 2, 2023

Human T-lymphotropic virus type 1 (HTLV-1)

High Risk

Poorly safe. Evaluate carefully. Use safer alternative or interrupt breastfeeding 3 to 7 T ½ (elimination half-lives). Read the Comment.

The human T-cell lymphotropic virus type 1 (HTLV-1) is a human retrovirus that causes an asymptomatic infection but is associated at a frequency of 1 to 10% (Leal 2015, Carneiro 2014) with a series of degenerative or immunological diseases such as tropical spastic paraparesis (TSP), T-cell leukemia or lymphoma, Sjögren's syndrome, arthritis and uveitis, Norwegian scabies, strongyloides stercoralis infestation and increased susceptibility to the development of tuberculosis infection and others (Garcia 2019, Gotuzzo 2010 and 2004). Infection is very prevalent in countries of western and central Africa, Peru, the Caribbean, Colombia, Brazil and Japan. (Rosadas 2019, Tagaya 2019)

HTLV-1 is transmitted mainly through breastfeeding (Millen 2022, Garcia 2019, Rosadas 2018, Boostani 2018, Carneiro 2014), especially if breastfeeding lasts more than 12 months (Paiva 2018). Transmission is more frequent if there is a higher viral load in the mother and there are siblings affected by HTLV-1 (Paiva 2018). In addition to HTLV-1/2 proviral DNA, anti-HTLV 1 and 2 IgG antibodies are detected in breast milk. (Rosadas 2021)

Other means of transmission are sexual contact and transfusions. Transplacental transmission and transmission during delivery are very rare.

The prevention of transmission adopted in some highly endemic countries is prenatal screening and formula feeding. (Ribeiro 2012)

Breastfeeding durations of up to 6 months are not associated with greater transmission of HTLV-1 than feeding with artificial formula: 4-6% (Boostani 2018), while breastfeeding for longer than 7 months is associated with transmissions from 14% to 32% (Boostani 2018, Rosadas 2019), which is why some authors suggest breastfeeding for a maximum of 6 months when socioeconomic conditions do not allow formula feeding in safe and sustainable conditions (Rosadas 2019, Mylonas 2010); in these situations, recommendations to not breastfeed or suspend it should be carefully made on a case-by-case basis. Gotuzzo 2004)

Feeding with expressed breastmilk frozen at -12º overnight has been used to nullify transmission (Ando 2004). Pasteurization also prevents transmission (Carneiro 2014). Although there is no known treatment for HTLV-1, antiretroviral therapy could be tried to prevent transmission through breastfeeding. (Leal 2015)

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Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

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Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Human T-lymphotropic virus type 1 (HTLV-1) is also known as


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  1. Millen S, Thoma-Kress AK. Milk Transmission of HTLV-1 and the Need for Innovative Prevention Strategies. Front Med (Lausanne). 2022 Mar 11;9:867147. Abstract Full text (link to original source)
  2. Van de Perre P, Molès JP, Nagot N, Tuaillon E, Ceccaldi PE, Goga A, Prendergast AJ, Rollins N. Revisiting Koch's postulate to determine the plausibility of viral transmission by human milk. Pediatr Allergy Immunol. 2021 Jul;32(5):835-842. Abstract Full text (link to original source)
  3. Rosadas C, Woo T, Haddow J, Rowan A, Taylor GP. Anti-HTLV-1/2 IgG Antibodies in the Breastmilk of Seropositive Mothers. Microorganisms. 2021 Jun 30;9(7). pii: 1413. Abstract Full text (link to original source)
  4. Garcia IFDS, Hennington ÉA. HTLV: a stigmatizing infection? Cad Saude Publica. 2019 Nov 11;35(11):e00005419. Abstract Full text (link to original source)
  5. Tagaya Y, Matsuoka M, Gallo R. 40 years of the human T-cell leukemia virus: past, present, and future. F1000Res. 2019 Feb 28;8. pii: F1000 Faculty Rev-228. Abstract Full text (link to original source)
  6. Prendergast AJ, Goga AE, Waitt C, Gessain A, Taylor GP, Rollins N, Abrams EJ, Lyall EH, de Perre PV. Transmission of CMV, HTLV-1, and HIV through breastmilk. Lancet Child Adolesc Health. 2019 Apr;3(4):264-273. Abstract
  7. Rosadas C, Taylor GP. Mother-to-Child HTLV-1 Transmission: Unmet Research Needs. Front Microbiol. 2019 May 8;10:999. Abstract Full text (link to original source)
  8. Boostani R, Sadeghi R, Sabouri A, Ghabeli-Juibary A. Human T-lymphotropic virus type I and breastfeeding; systematic review and meta-analysis of the literature. Iran J Neurol. 2018 Oct 7;17(4):174-179. Review. Abstract Full text (link to original source)
  9. Paiva AM, Assone T, Haziot MEJ, Smid J, Fonseca LAM, Luiz ODC, de Oliveira ACP, Casseb J. Risk factors associated with HTLV-1 vertical transmission in Brazil: longer breastfeeding, higher maternal proviral load and previous HTLV-1-infected offspring. Sci Rep. 2018 May 17;8(1):7742. Abstract Full text (link to original source)
  10. Leal FE, Michniowski M, Nixon DF. Human T-lymphotropic virus 1, breastfeeding, and antiretroviral therapy. AIDS Res Hum Retroviruses. 2015 Mar;31(3):271. Abstract
  11. Carneiro-Proietti AB, Amaranto-Damasio MS, Leal-Horiguchi CF, Bastos RH, Seabra-Freitas G, Borowiak DR, Ribeiro MA, Proietti FA, Ferreira AS, Martins ML. Mother-to-Child Transmission of Human T-Cell Lymphotropic Viruses-1/2: What We Know, and What Are the Gaps in Understanding and Preventing This Route of Infection. J Pediatric Infect Dis Soc. 2014 Sep;3 Suppl 1:S24-9. Abstract Full text (link to original source)
  12. Ribeiro MA, Martins ML, Teixeira C, Ladeira R, Oliveira Mde F, Januário JN, Proietti FA, Carneiro-Proietti AB. Blocking vertical transmission of human T cell lymphotropic virus type 1 and 2 through breastfeeding interruption. Pediatr Infect Dis J. 2012 Nov;31(11):1139-43. Abstract
  13. Eduardo Gotuzzo Herencia, Elsa González Lagos, Kristien Verdonck Bosteels, Erick Mayer Arispe, Fanny Ita Nagy, Daniel Clark Leza. Veinte años de investigación sobre HTLV-1 y sus complicaciones médicas en el Perú: Perspectivas generales. Twenty years of research on HTLV-1 and its medical complications in Peru: general perspectives. Acta Med Per 2010;27(3):196-203. Full text (link to original source) Full text (in our servers)
  14. Mylonas I, Brüning A, Kainer F, Friese K. HTLV infection and its implication in gynaecology and obstetrics. Arch Gynecol Obstet. 2010 Nov;282(5):493-501. Abstract
  15. Gotuzzo E, Verdonck K, González E, Cabada M. Virus linfotrópico humano de células T tipo 1 (HTLV-1): Una infección endémica en el Perú. Rev Peru Med Exp Salud Pub. 2004;21(4):253-260 Full text (link to original source) Full text (in our servers)
  16. Ando Y, Ekuni Y, Matsumoto Y, Nakano S, Saito K, Kakimoto K, Tanigawa T, Kawa M, Toyama T. Long-term serological outcome of infants who received frozen-thawed milk from human T-lymphotropic virus type-I positive mothers. J Obstet Gynaecol Res. 2004 Dec;30(6):436-8. Abstract
  17. Toro C, Rodés B, Aguilera A, Caballero E, Benito R, Bassani S, Rodríguez C, Tuset C, Ortiz de Lejarazu R, Eirós J, García J, Calderón E, Capote FJ, Vallejo A, Gutiérrez M, Soriano V; Grupo Español para el Estudio del VIH-2 y del HTLV-I/II.. Infecciones por VIH-2 y HTLV-I/II en España. [HIV-2 and HTLV-I/II infections in Spain]. Enferm Infecc Microbiol Clin. 2004 Mar;22(3):177-82. Spanish. Abstract Full text (link to original source)

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