“ it ’s pretty obvious that in all seven sites there is a clear relationship , ” said dr. marcos a. espinal , the study ’s lead author and the director of communicable diseases at the pan american health organization , which collected data on confirmed and suspected cases . nejm.org uses cookies to continue . ” in venezuela , officials expected roughly 70 cases of guillain - barré from december 2015 to the end of march 2016 , as mosquitoes were spreading the virus . jennifer weiss nbc news “ during the weeks of zika virus transmission , there were significant increases in the incidence of the guillain – barré syndrome , as compared with the pre - zika virus guillain - barré syndrome ( gbs ) is an uncommon sickness of the nervous system in which a person ’s own immune system damages the nerve cells , causing muscle weakness , and sometimes , paralysis . instances of guillain - barré skyrocketed in countries hit by zika virus epidemics — by as much as 877 percent in venezuela , health officials and researchers from latin america reported . similarly , during five months in which the zika virus was circulating in colombia , officials recorded 320 cases of guillain - barré when there should have been about 100 . current cdc research suggests that gbs and zika to learn more . 1 - 800 - 843 - 6356 | [ email protected ] there ’s more evidence that zika virus infection can cause a paralyzing side effect called guillain - barré syndrome . several countries that have experienced zika outbreaks recently have reported increases in people who have guillain - barré syndrome ( gbs ) .