Medline ® Abstracts for References 27,113-120

Guillain-Barrésyndrome (GBS) is a postinfectious autoimmune disorder characterized by bilateral flaccid limb weakness attributable to peripheral nerve damage (1). Increased GBS incidence has been reported in countries with local transmission of Zika virus, a flavivirus transmitted primarily by certain Aedes species mosquitoes (2). In Puerto Rico, three arthropod-borne viruses (arboviruses) are currently circulating: Zika, dengue, and chikungunya. The first locally acquired Zika virus infection in Puerto Rico was reported in December 2015 (3). In February 2016, the Puerto Rico Department of Health (PRDH), with assistance from CDC, implemented the GBS Passive Surveillance System (GBPSS) to identify new cases of suspected GBS (4). Fifty-six suspected cases of GBS with onset of neurologic signs during January 1-July 31, 2016, were identified. Thirty-four (61%) patients had evidence of Zika virus or flavivirus infection; the median age of these patients was 55 years (range = 21-88 years), and 20 (59%) patients were female. These 34 patients were residents of seven of eight PRDH public health regions. All 34 patients were hospitalized and treated with intravenous immunoglobulin G (IVIg), the standard treatment for GBS; 21 (62%) required intensive care unit admission, including 12 (35%) who required endotracheal intubation and mechanical ventilation. One patient died of septic shock after treatment for GBS. Additionally, 26 cases of neurologic conditions other than GBS were reported through GBPSS, including seven (27%) in patients with evidence of Zika virus or flavivirus infection. Residents of and travelers to Puerto Rico and countries with active Zika virus transmission should follow recommendations for prevention of Zika virus infections.* Persons with signs or symptoms consistent with GBS should promptly seek medical attention. Health care providers in areas with ongoing local transmission seeing patients with neurologic illnesses should consider GBS and report suspected cases to public health authorities.

BACKGROUND: Zika virus (ZIKV) infection has been linked to the Guillain-Barrésyndrome. From November 2015 through March 2016, clusters of cases of the Guillain-Barrésyndrome were observed during the outbreak of ZIKV infection in Colombia. We characterized the clinical features of cases of Guillain-Barrésyndrome in the context of this ZIKV infection outbreak and investigated their relationship with ZIKV infection.

METHODS: A total of 68 patients with the Guillain-Barrésyndrome at six Colombian hospitals were evaluated clinically, and virologic studies were completed for 42 of the patients. We performed reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assays for ZIKV in blood, cerebrospinal fluid, and urine, as well as antiflavivirus antibody assays.

RESULTS: A total of 66 patients (97%) had symptoms compatible with ZIKV infection before the onset of the Guillain-Barrésyndrome. The median period between the onset of symptoms of ZIKV infection and symptoms of the Guillain-Barrésyndrome was 7 days (interquartile range, 3 to 10). Among the 68 patients with the Guillain-Barrésyndrome, 50% were found to have bilateral facial paralysis on examination. Among 46 patients in whom nerve-conduction studies and electromyography were performed, the results in 36 patients (78%) were consistent with the acute inflammatory demyelinating polyneuropathy subtype of the Guillain-Barrésyndrome. Among the 42 patients who had samples tested for ZIKV by RT-PCR, the results were positive in 17 patients (40%). Most of the positive RT-PCR results were in urine samples (in 16 of the 17 patients with positive RT-PCR results), although 3 samples of cerebrospinal fluid were also positive. In 18 of 42 patients (43%) with the Guillain-Barrésyndrome who underwent laboratory testing, the presence of ZIKV infection was supported by clinical and immunologic findings. In 20 of these 42 patients (48%), the Guillain-Barrésyndrome had a parainfectious onset. All patients tested were negative for dengue virus infection as assessed by RT-PCR.

CONCLUSIONS: The evidence of ZIKV infection documented by RT-PCR among patients with the Guillain-Barrésyndrome during the outbreak of ZIKV infection in Colombia lends support to the role of the infection in the development of the Guillain-Barrésyndrome. (Funded by the Bart McLean Fund for Neuroimmunology Research and others.).

Zika fever, considered as an emerging disease of arboviral origin, because of its expanding geographic area, is known as a benign infection usually presenting as an influenza-like illness with cutaneous rash. So far, Zika virus infection has never led to hospitalisation. We describe the first case of Guillain-Barrésyndrome (GBS) occurring immediately after a Zika virus infection, during the current Zika and type 1 and 3 dengue fever co-epidemics in French Polynesia.

BACKGROUND: Between October, 2013, and April, 2014, French Polynesia experienced the largest Zika virus outbreak ever described at that time. During the same period, an increase in Guillain-Barrésyndrome was reported, suggesting a possible association between Zika virus and Guillain-Barrésyndrome. We aimed to assess the role of Zika virus and dengue virus infection in developing Guillain-Barrésyndrome.

METHODS: In this case-control study, cases were patients with Guillain-Barrésyndrome diagnosed at the Centre Hospitalier de Polynésie Française (Papeete, Tahiti, French Polynesia) during the outbreak period. Controls were age-matched, sex-matched, and residence-matched patients who presented at the hospital with a non-febrile illness (control group 1; n=98) and age-matched patients with acute Zika virus disease and no neurological symptoms (control group 2; n=70). Virological investigations included RT-PCR for Zika virus, and both microsphere immunofluorescent and seroneutralisation assays for Zika virus and dengue virus. Anti-glycolipid reactivity was studied in patients with Guillain-Barrésyndrome using both ELISA and combinatorial microarrays.

FINDINGS: 42 patients were diagnosed with Guillain-Barrésyndrome during the study period. 41 (98%) patients with Guillain-Barrésyndrome had anti-Zika virus IgM or IgG, and all (100%) had neutralising antibodies against Zika virus compared with 54 (56%) of 98 in control group 1 (p<0.0001). 39 (93%) patients with Guillain-Barrésyndrome had Zika virus IgM and 37 (88%) had experienced a transient illness in a median of 6 days (IQR 4-10) before the onset of neurological symptoms, suggesting recent Zika virus infection. Patients with Guillain-Barrésyndrome had electrophysiological findings compatible with acute motor axonal neuropathy (AMAN) type, and had rapid evolution of disease (median duration of the installation and plateau phases was 6 [IQR 4-9]and 4 days [3-10], respectively). 12 (29%) patients required respiratory assistance. No patients died. Anti-glycolipid antibody activity was found in 13 (31%) patients, and notably against GA1 in eight (19%) patients, by ELISA and 19 (46%) of 41 by glycoarray at admission. The typical AMAN-associated anti-ganglioside antibodies were rarely present. Past dengue virus history did not differ significantly between patients with Guillain-Barrésyndrome and those in the two control groups (95%, 89%, and 83%, respectively).

INTERPRETATION: This is the first study providing evidence for Zika virus infection causing Guillain-Barrésyndrome. Because Zika virus is spreading rapidly across the Americas, at risk countries need to prepare for adequate intensive care beds capacity to manage patients with Guillain-Barrésyndrome.

FUNDING: Labex Integrative Biology of Emerging Infectious Diseases, EU 7th framework program PREDEMICS. and Wellcome Trust.

Zika virus infection emerged as a public health emergency after increasing evidence for its association with neurologic disorders and congenital malformations. In Salvador, Brazil, outbreaks of acute exanthematous illness (AEI) attributed to Zika virus, Guillain-Barrésyndrome (GBS), and microcephaly occurred in 2015. We investigated temporal correlations and time lags between these outbreaks to identify a common link between them by using epidemic curves and time series cross-correlations. Number of GBS cases peaked after a lag of 5-9 weeks from the AEI peak. Number of suspected cases of microcephaly peaked after a lag of 30-33 weeks from the AEI peak, which corresponded to time of potential infections of pregnant mothers during the first trimester. These findings support the association of GBS and microcephaly with Zika virus infection and provide evidence for a temporal relationship between timing of arboviral infection of pregnant women during the first trimester and birth outcome.

BACKGROUND: The World Health Organization (WHO) stated in March 2016 that there was scientific consensus that the mosquito-borne Zika virus was a cause of the neurological disorder Guillain-Barrésyndrome (GBS) and of microcephaly and other congenital brain abnormalities based on rapid evidence assessments. Decisions about causality require systematic assessment to guide public health actions. The objectives of this study were to update and reassess the evidence for causality through a rapid and systematic review about links between Zika virus infection and (a) congenital brain abnormalities, including microcephaly, in the foetuses and offspring of pregnant women and (b) GBS in any population, and to describe the process and outcomes of an expert assessment of the evidence about causality.

METHODS AND FINDINGS: The study had three linked components. First, in February 2016, we developed a causality framework that defined questions about the relationship between Zika virus infection and each of the two clinical outcomes in ten dimensions: temporality, biological plausibility, strength of association, alternative explanations, cessation, dose-response relationship, animal experiments, analogy, specificity, and consistency. Second, we did a systematic review (protocol number CRD42016036693). We searched multiple online sources up to May 30, 2016 to find studies that directly addressed either outcome and any causality dimension, used methods to expedite study selection, data extraction, and quality assessment, and summarised evidence descriptively. Third, WHO convened a multidisciplinary panel of experts who assessed the review findings and reached consensus statements to update the WHO position on causality. We found 1,091 unique items up to May 30, 2016. For congenital brain abnormalities, including microcephaly, we included 72 items; for eight of ten causality dimensions (all except dose-response relationship and specificity), we found that more than half the relevant studies supported a causal association with Zika virus infection. For GBS, we included 36 items, of which more than half the relevant studies supported a causal association in seven of ten dimensions (all except dose-response relationship, specificity, and animal experimental evidence). Articles identified nonsystematically from May 30 to July 29, 2016 strengthened the review findings. The expert panel concluded that (a) the most likely explanation of available evidence from outbreaks of Zika virus infection and clusters of microcephaly is that Zika virus infection during pregnancy is a cause of congenital brain abnormalities including microcephaly, and (b) the most likely explanation of available evidence from outbreaks of Zika virus infection and GBS is that Zika virus infection is a trigger of GBS. The expert panel recognised that Zika virus alone may not be sufficient to cause either congenital brain abnormalities or GBS but agreed that the evidence was sufficient to recommend increased public health measures. Weaknesses are the limited assessment of the role of dengue virus and other possible cofactors, the small number of comparative epidemiological studies, and the difficulty in keeping the review up todate with the pace of publication of new research.

CONCLUSIONS: Rapid and systematic reviews with frequent updating and open dissemination are now needed both for appraisal of the evidence about Zika virus infection and for the next public health threats that will emerge. This systematic review found sufficient evidence to say that Zika virus is a cause of congenital abnormalities and is a trigger of GBS.

Zika virus, a mosquito-borne flavivirus that can cause rash with fever, emerged in the Region of the Americas on Easter Island, Chile, in 2014 and in northeast Brazil in 2015 (1). In response, in May 2015, the Pan American Health Organization (PAHO), which serves as the Regional Office of the Americas for the World Health Organization (WHO), issued recommendations to enhance surveillance for Zika virus. Subsequently, Brazilian investigators reported Guillain-Barrésyndrome (GBS), which had been previously recognized among some patients with Zika virus disease, and identified an association between Zika virus infection during pregnancy and congenital microcephaly (2). On February 1, 2016, WHO declared Zika virus-related microcephaly clusters and other neurologic disorders a Public Health Emergency of International Concern.* In March 2016, PAHO developed case definitions and surveillance guidance for Zika virus disease and associated complications (3). Analysis of reports submitted to PAHO by countries in the region or published in national epidemiologic bulletins revealed that Zika virus transmission had extended to 48 countries and territories in the Region of the Americas by late 2016. Reported Zika virus disease cases peaked at different times in different areas during 2016. Because of ongoing transmission and the risk for recurrence of large outbreaks, response efforts, including surveillance for Zika virus disease and its complications, and vector control and other prevention activities, need to be maintained.