from the DIY-all-natural-organic-topical-cream dept.
While an infected man’s semen may be teeming with hundreds of millions of Zika viruses, the number of people who have been infected with this virus via sexual intercourse is relatively low. Instead, Zika is usually transmitted by a mosquito bite. An international research team headed by Ulm University's Professor Jan Münch has now discovered that semen blocks Zika virus infection. Responsible for this effect are small vesicles that are naturally present in semen and make it harder for the virus to attach to cells of the anogenital tract. The results were published recently in the journal Nature Communications.
[...] 'We were very surprised to find that semen inhibits Zika virus infection instead of enhancing its infectivity as it does with HIV-1,' says first author Dr. Janis Müller, who works as postdoctoral scientist at the Institute of Molecular Virology. The international research team demonstrated that Zika virus replicates efficiently in cells isolated from both genital and rectal tissues. When the cells were exposed to semen before infection with Zika, however, infection rates were significantly lower.
What is responsible for this antiviral effect? Using a wide array of methods – from molecular weight filtration and nanoparticle tracking analysis to fluorescence, confocal and electron microscopy – the scientists eventually uncovered the identity of the 'virus stopper'. 'Extracellular vesicles, which are present in semen in large numbers, reduce attachment of the virus to the cells and thus prevent infection,' Münch explains. These vesicles are bubble-like particles consisting of membranes and proteins and are responsible for the transport and storage of substances to cells.