Post by The Lancet Infectious Diseases

🔥Unprotected sex is the main route of human T-lymphotropic virus type 1 (HTLV-1) transmission, followed by vertical transmission. Context-specific exposures add substantial local burdens in central Africa and central Australia. 💡Noé Ochida and colleagues following a systematic review, analysed data on sex-and age-stratified HTLV-1 seroprevalence from seven seroprevalence surveys across nine subpopulations in French Guiana, rural Gabon, rural Cameroon, Japan (Miyazaki, Iriomote, and Ishigaki), and central Australia. Subsequently, authors developed a serocatalytic model to quantify the contribution of different transmission routes to the spread and endemicity of HTLV-1 in various countries across the globe. Primary outcome was the model-estimated route-specific force of infection by age, sex, and subpopulation, from which authors derived the attributable fraction of infections due to each transmission route. 📊 Across populations, sexual and vertical transmission contributed to 85% (95% CI 79–87) and 8% (95% CI 7–9) of infections in adults aged 25–69 years. Probability of mother-to-child transmission was found to be around 17%. Hospital-related transmission contributed to around 2% of all infections in Japan (pre-HTLV-1 blood-safety measures), around 5% in Cameroonian Bantu communities, and less than 1% elsewhere. NHP bite-related transmission accounted for up to 26% of adult male infections in Cameroonian Bantu rural communities and up to 9% elsewhere in central Africa. An unknown male-specific transmission route in central Australia was found. 🔦 First study to quantify how different transmission routes can contribute to the spread of HTLV-1, accounting also for specific routes in particular settings. These route-specific estimates support intervention prioritisation and the design of setting-specific control strategies. Read the full paper here: https://bit.ly/3QHXiCL #HTLV-1, #transmission, #modelling Jill-Lea Ramassamy, Delia Doreen Djuicy, Sabine Plancoulaine, Augustin Mouinga-Ondémé, Chanceline Bilounga Ndongo, Njouom Richard, Toshiki Watanabe, Lloyd Einsiedel, Raphaëlle Métras, Antoine Gessain, Simon Cauchemez