President Dilma Rousseff of Brazil urged residents in the city of Recife to make an effort to fight the spread of the Zika virus, which is transmitted by the Aedes aegypti mosquito and is linked to severe brain damage in infants. By THE ASSOCIATED PRESS on Publish Date January 21, 2016. Photo by Andre Penner/Associated Press.

RIO DE JANEIRO — A mosquito-borne virus that has been linked tosevere brain damage in infants may be causing another serious health crisis as well, Brazilian officials and doctors warn: hundreds of cases of a rare syndrome in which patients can be almost completely paralyzed for weeks.

The virus, called Zika, made its way to Brazil recently but is spreading rapidly around Latin America and the Caribbean. Nearly 4,000 cases of brain damage, in which babies were born with unusually small heads, have been registered in Brazil in the past year, and this month American officials advised pregnant women to delay traveling to any of nearly 20 countries in the Western Hemisphere, as well as Puerto Rico, where mosquitoes are spreading the virus.

But disease specialists in Brazil say that the virus may also be causing a surge in another rare condition, the potentially life-threatening Guillain-Barré syndrome, in which a person’s immune system attacks part of the nervous system, leaving some patients unable to move and dependent on life support.


A researcher at São Paulo University in Brazil with Aedes aegypti mosquitoes. Officials are investigating a possible link between the Zika virus and an increase in the number of cases of Guillain-Barré, a rare autoimmune condition. CreditAndre Penner/Associated Press

Until recently, the condition was so rare that Brazil’s Health Ministry did not require regional officials to report it. But last year, the authorities in northeast Brazil, the part of the country hit hardest by the Zika virus, counted hundreds of cases of Guillain-Barré, prompting doctors to sound the alarm.