Though not common knowledge, infectious diseases often prove more fatal in men than in women. In the past, this difference has been attributed to women having more robust immune responses, but a recently published article in Nature Communications may prove otherwise. Researchers Francisco Ubeda and Vincent Jansen, of Royal Holloway, University of London, studied the progression of Human T-cell Lymphotropic Virus I (HTLV-1) into adult T-cell leukemia, in Japanese and Caribbean cohorts to try and learn more about these sexually-based differences. In the Japanese group, the progression occurs 2 to 3.5 times more frequently in men, while the progression occurs at an equal rate within the Caribbean cohort. The team has proposed that cultural differences in breast feeding may help to explain the discrepancy between the two groups.
HTLV-1 is a virus transmitted through sexual contact and breastfeeding. In Japan, mothers breast feed their children for longer durations, and in larger quantities than Caribbean women do. Ubeda and Jansen argue that the virus has developed a lower virulence within Japanese women relative to Caribbean women, due to its increased vertical transmission rate in the Japanese group (due to the increased duration and frequencies of breastfeeding in the Japanese group). To back their hypothesis, the team developed a mathematical model, which did show increased selection for viruses with differing mortalities between sexes, for viruses transmitted both horizontally and vertically. Ubeda and Jansen hope that this work helps lead to more effective, sex specific treatments for HTLV-1, and other viruses with sex-specific virulences.
Ahmed Mustafa ('18)