Brazilian health authorities have notified the PAHO/WHO of an increase of Guillain-Barre Syndrome (GBS) recorded at the national level.
Data from the hospital-based surveillance system reveal that, between January and November 2015, 1,708 cases of GBS were registered nationwide. While a number of states reported significant increases in reported cases – especially, Alagoas (516.7%), Bahia (196.1%), Rio Grande do Norte (108.7%), Piauí (108.3%), Espirito Santo (78.6%), and Rio de Janeiro (60.9%) – other states reported stable or even diminishing number of GBS cases as compared to 2014. Most of the states in Brazil are experiencing the circulation of Zika, chikungunya, and dengue virus.
At present, available information is insufficient to interpret the observed differences in GBS incidence globally and among Brazilian states. The potential cause of the reported increase of GBS incidence in certain Brazilian states remains unknown. Case-control studies are ongoing to determine the cause of the increase. These studies may provide evidence that corroborates or disproves a causal relationship between Zika virus, GBS and other congenital malformations.