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New estimates of the Zika virus epidemic attack rate in Northeastern Brazil from 2015 to 2016: A modelling analysis based on Guillain-Barre Syndrome (GBS) surveillance data.

ABSTRACT: BACKGROUND:Between January 2015 and August 2016, two epidemic waves of Zika virus (ZIKV) disease swept the Northeastern (NE) region of Brazil. As a result, two waves of Guillain-Barré Syndrome (GBS) were observed concurrently. The mandatory reporting of ZIKV disease began region-wide in February 2016, and it is believed that ZIKV cases were significantly under-reported before that. The changing reporting rate has made it difficult to estimate the ZIKV infection attack rate, and studies in the literature vary widely from 17% to > 50%. The same applies to other key epidemiological parameters. In contrast, the diagnosis and reporting of GBS cases were reasonably reliable given the severity and easy recognition of the disease symptoms. In this paper, we aim to estimate the real number of ZIKV cases (i.e., the infection attack rate) and their dynamics in time, by scaling up from GBS surveillance data in NE Brazil. METHODOLOGY:A mathematical compartmental model is constructed that makes it possible to infer the true epidemic dynamics of ZIKV cases based on surveillance data of excess GBS cases. The model includes the possibility that asymptomatic ZIKV cases are infectious. The model is fitted to the GBS surveillance data and the key epidemiological parameters are inferred by using a plug-and-play likelihood-based estimation. We make use of regional weather data to determine possible climate-driven impacts on the reproductive number [Formula: see text], and to infer the true ZIKV epidemic dynamics. FINDINGS AND CONCLUSIONS:The GBS surveillance data can be used to study ZIKV epidemics and may be appropriate when ZIKV reporting rates are not well understood. The overall infection attack rate (IAR) of ZIKV is estimated to be 24.1% (95% confidence interval: 17.1%-29.3%) of the population. By examining various asymptomatic scenarios, the IAR is likely to be lower than 33% over the two ZIKV waves. The risk rate from symptomatic ZIKV infection to develop GBS was estimated as ? = 0.0061% (95% CI: 0.0050%-0.0086%) which is significantly less than current estimates. We found a positive association between local temperature and the basic reproduction number, [Formula: see text]. Our analysis revealed that asymptomatic infections affect the estimation of ZIKV epidemics and need to also be carefully considered in related modelling studies. According to the estimated effective reproduction number and population wide susceptibility, we comment that a ZIKV outbreak would be unlikely in NE Brazil in the near future.

SUBMITTER: He D

PROVIDER: S-EPMC7213748 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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New estimates of the Zika virus epidemic attack rate in Northeastern Brazil from 2015 to 2016: A modelling analysis based on Guillain-Barré Syndrome (GBS) surveillance data.

He Daihai D Zhao Shi S Lin Qianying Q Musa Salihu S SS Stone Lewi L

PLoS neglected tropical diseases 20200429 4

<h4>Background</h4>Between January 2015 and August 2016, two epidemic waves of Zika virus (ZIKV) disease swept the Northeastern (NE) region of Brazil. As a result, two waves of Guillain-Barré Syndrome (GBS) were observed concurrently. The mandatory reporting of ZIKV disease began region-wide in February 2016, and it is believed that ZIKV cases were significantly under-reported before that. The changing reporting rate has made it difficult to estimate the ZIKV infection attack rate, and studies i ...[more]

PMID: 32348302

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Project description:BackgroundA severe neurological disorder, Guillain-Barré syndrome (GBS) is the leading cause of acute flaccid paralysis. Enhanced surveillance of GBS in Latin America and the Caribbean (LAC) following the 2015-2016 Zika virus (ZIKV) epidemic presents an opportunity to estimate, for the first time, the regional incidence of GBS.Methods and findingsFor this systematic review and meta-analysis, we searched nine scientific databases and grey literature from January 1, 1980 to October 1, 2018. Sources with primary data on incident GBS cases in LAC within a well-defined population and timeframe, published in English, Spanish, Portuguese, or French, were included. We calculated the annual GBS incidence rates (IRs) and 95% confidence intervals (CIs) for each source based on published data. Following an assessment of heterogeneity, we used random-effects meta-analysis to calculate the pooled annual IR of GBS. The study is registered with PROSPERO, number CRD42018086659. Of the 6568 initial citation hits, 31 were eligible for inclusion. Background annual GBS IRs in Latin America ranged from 0.40 in Brazil to 2.12/100,000 in Chile. The pooled annual IR in the Caribbean was 1.64 (95% CI 1.29-2.12, I2<0.01, p = 0.44). During the ZIKV epidemic, GBS IRs ranged from 0.62 in Mexico to 9.35/100,000 in Martinique. GBS increased 2.6 (95% CI 2.3-2.9) times during ZIKV and 1.9 (95% CI 1.1-3.4) times during chikungunya outbreaks over background rates. A limitation of this review is that the studies included employed different methodologies to find and ascertain cases of GBS, which could contribute to IR heterogeneity. In addition, it is important to consider that data on GBS are lacking for many countries in the region.ConclusionsBackground IRs of GBS appear to peak during arboviral disease outbreaks. The current review contributes to an understanding of the epidemiology of GBS in the LAC region, which can inform healthcare system planning and preparedness, particularly during arboviral epidemics.Trial registrationRegistered with PROSPERO: CRD42018086659.

Project description:Importance:The pathophysiologic mechanisms of Guillain-Barré syndrome (GBS) associated with Zika virus (ZIKV) infection may be indicated by differences in clinical features. Objective:To identify specific clinical features of GBS associated with ZIKV infection. Design, Setting, and Participants:During the ZIKV epidemic in Puerto Rico, prospective and retrospective strategies were used to identify patients with GBS who had neurologic illness onset in 2016 and were hospitalized at all 57 nonspecialized hospitals and 2 rehabilitation centers in Puerto Rico. Guillain-Barré syndrome diagnosis was confirmed via medical record review using the Brighton Collaboration criteria. Specimens (serum, urine, cerebrospinal fluid, and saliva) from patients with GBS were tested for evidence of ZIKV infection by real-time reverse transcriptase-polymerase chain reaction; serum and cerebrospinal fluid were also tested by IgM enzyme-linked immunosorbent assay. In this analysis of public health surveillance data, a total of 123 confirmed GBS cases were identified, of which 107 had specimens submitted for testing; there were 71 patients with and 36 patients without evidence of ZIKV infection. Follow-up telephone interviews with patients were conducted 6 months after neurologic illness onset; 60 patients with and 27 patients without evidence of ZIKV infection participated. Main Outcomes and Measures:Acute and long-term clinical characteristics of GBS associated with ZIKV infection. Results:Of 123 patients with confirmed GBS, the median age was 54 years (age range, 4-88 years), and 68 patients (55.3%) were male. The following clinical features were more frequent among patients with GBS and evidence of ZIKV infection compared with patients with GBS without evidence of ZIKV infection: facial weakness (44 [62.0%] vs 10 [27.8%]; P?<?.001), dysphagia (38 [53.5%] vs 9 [25.0%]; P?=?.005), shortness of breath (33 [46.5%] vs 9 [25.0%]; P?=?.03), facial paresthesia (13 [18.3%] vs 1 [2.8%]; P?=?.03), elevated levels of protein in cerebrospinal fluid (49 [94.2%] vs 23 [71.9%]; P?=?.008), admission to the intensive care unit (47 [66.2%] vs 16 [44.4%]; P?=?.03), and required mechanical ventilation (22 [31.0%] vs 4 [11.1%]; P?=?.02). Six months after neurologic illness onset, patients with GBS and evidence of ZIKV infection more frequently reported having excessive or inadequate tearing (30 [53.6%] vs 6 [26.1%]; P?=?.03), difficulty drinking from a cup (10 [17.9%] vs 0; P?=?.03), and self-reported substantial pain (15 [27.3%] vs 1 [4.3%]; P?=?.03). Conclusions and Relevance:In this study, GBS associated with ZIKV infection was found to have higher morbidity during the acute phase and more frequent cranial neuropathy during acute neuropathy and 6 months afterward. Results indicate GBS pathophysiologic mechanisms that may be more common after ZIKV infection.

Project description:BackgroundGuillain-Barré syndrome (GBS) is the most prevalent acute autoimmune polyneuropathy, however, the incidence of GBS across China remains undetermined. We conducted the first nationwide study to extrapolate the incidence and mortality rates of GBS across all age groups at a national scale.MethodsThis study analyzed patient metrics from the National Hospital Quality Monitoring System, a comprehensive administrative database of which incorporate all 1665 tertiary hospitals in mainland China. For all study patients the "Medical Record Homepage" encompasses 346 distinct variables such as demographic characteristics, diagnoses, procedures, expenses, etc., that are systematically recorded from these hospitals by standard protocol. All GBS diagnoses adhered to the National Institute of Neurologic and Communicative Disorders and Stroke (NINCDS) diagnostic criteria and were identified with ICD-10 code (G61•0).FindingsFrom 2016 to 2019, 75,548 hospital admissions for 38,861 GBS patients were identified. The age- and sex-adjusted incidence per 100,000 person-years is 0·698 (95% confidence interval [CI], 0·691-0·705), 0·233(0·225-0·242) in children and 0·829(0·820-0·837) in adults. The male-to-female ratio is 1·49. Peak disease onset was detected in the 70-74 years age group with an incidence of 1·806/100, 000 (95% CI, 1·741-1·870). Recognizable GBS distribution patterns were recognized in the southeastern coastal areas, where the cases of GBS were concentrated in the summer and autumn seasons. Prevalent comorbidities include hypertension (28·8%) and stroke (14·3%). The median length of hospitalization was 13·0 (8·0-18·0) days with a median hospitalization cost of $2371·60 ($1281·80-5463·60). Covering 69·9% of study patients, the Basic Medical Insurance was the most common payment mechanism. From 2016-2019, 426 adults and 13 children died in this study pool, with a hospital mortality rate of 11·2 per 1,000 person-years.InterpretationFor the first time, we obtained a national incidence for GBS at 0·233 in children and 0·829 in adults per 100,000 in China. A differential spatiotemporal incidence is presented most southeast coastal areas in the summer and autumn seasons.FundingNational Science Foundation of China (91949208, 91642205, and 81830038); Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing.

Project description:BackgroundZika virus (ZIKV) emerged as a global epidemic in 2015-2016 from Latin America with its true geographical extent remaining unclear due to widely presumed underreporting. The identification of locations with potential and unknown spread of ZIKV is a key yet understudied component for outbreak preparedness. Here, we aim to identify locations at a high risk of cryptic ZIKV spread during 2015-2016 to further the understanding of the global ZIKV epidemiology, which is critical for the mitigation of the risk of future epidemics.MethodsWe developed an importation simulation model to estimate the weekly number of ZIKV infections imported in each susceptible spatial unit (i.e. location that did not report any autochthonous Zika cases during 2015-2016), integrating epidemiological, demographic, and travel data as model inputs. Thereafter, a global risk model was applied to estimate the weekly ZIKV transmissibility during 2015-2016 for each location. Finally, we assessed the risk of onward ZIKV spread following importation in each susceptible spatial unit to identify locations with a high potential for cryptic ZIKV spread during 2015-2016.ResultsWe have found 24 susceptible spatial units that were likely to have experienced cryptic ZIKV spread during 2015-2016, of which 10 continue to have a high risk estimate within a highly conservative scenario, namely, Luanda in Angola, Banten in Indonesia, Maharashtra in India, Lagos in Nigeria, Taiwan and Guangdong in China, Dakar in Senegal, Maputo in Mozambique, Kinshasa in Congo DRC, and Pool in Congo. Notably, among the 24 susceptible spatial units identified, some have reported their first ZIKV outbreaks since 2017, thus adding to the credibility of our results (derived using 2015-2016 data only).ConclusionOur study has provided valuable insights into the potentially high-risk locations for cryptic ZIKV circulation during the 2015-2016 pandemic and has also laid a foundation for future studies that attempt to further narrow this key knowledge gap. Our modelling framework can be adapted to identify areas with likely unknown spread of other emerging vector-borne diseases, which has important implications for public health readiness especially in resource-limited settings.

Dataset Information

New estimates of the Zika virus epidemic attack rate in Northeastern Brazil from 2015 to 2016: A modelling analysis based on Guillain-Barre Syndrome (GBS) surveillance data.

Publications

New estimates of the Zika virus epidemic attack rate in Northeastern Brazil from 2015 to 2016: A modelling analysis based on Guillain-Barré Syndrome (GBS) surveillance data.

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