Paralysis and neurological disorders, such as the Guillain-Barré syndrome (GBS), are increasing in Latin American countries and its links to the Zika virus outbreak could be getting stronger, the World Health Organization (WHO) confirmed in a new report.

The health agency cites that Guillain-Barré have spiked in countries like Brazil, Colombia, El Salvador, Suriname and Venezuela, coinciding with the rise of Zika cases in the region.

In the case of Colombia, which averages 242 Guillain-Barré cases yearly, at least 86 cases have been reported since January 2016 while 76 cases of neurological disorders have been reported in Brazil. Of these, 55 percent were confirmed Guillain-Barré cases and 26 percent have had a history of Zika infection.

On the other hand, El Salvador has had 46 reported cases of Guillain-Barré in a matter of five weeks. The country averagely receives 169 cases of the syndrome within a full year.

Salvadoran doctor Antonio Bandeira witnessed the increase in patients with symptoms of the neurological disorder at his hospital in 2015 when Zika was still relatively under the radar. "Zika was really bad here from February to July and then all but disappeared in August. In May, June and July, we had 24 patients come in with Guillain-Barre, and none since August," he told ABC News.

Guillain-Barre attacks a person's nervous system, affecting a part of the brain that sends signals to the muscular nerves. The disorder causes a person to lose control of his fine motor skills and he may often experience tingling and numbness on his limbs. He may also grow physically weaker, lose his balance or mouth functions like speaking or swallowing, per Mayo Clinic.

However, WHO also cautioned that the "cause of the increase in GBS incidence...remains unknown, especially as dengue, chikungunya, and Zika virus have all been circulating simultaneously in the Americas," CBS News reports.

The Associated Press (AP) cites that, historically, about one or two in 100,000 people could develop the auto-immune disorder from a viral or bacterial infection and 20 patients could end up dying from the disease. "It's an epidemiological association," Dr. Jairo Lizarazo told AP. "We don't know exactly how it works. But it's there, for sure."

Scientists and doctors are still learning about Zika and a chief neurologist in Brazil, Dr. Maria Lucia Brito Ferreira, is waiting to get more laboratory test results that could confirm nine Guillain-Barre deaths have been Zika-related.

It should be noted that reporting cases is not compulsory, so concerned agencies have yet to find other ways to fully grasp the gravity of the outbreak.