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Correction for “An open challenge to advance probabilistic forecasting for dengue epidemics,” by Michael A. Johansson, Karyn M. Apfeldorf, Scott Dobson, Jason Devita, Anna L. Buczak, Benjamin Baugher, Linda J. Moniz, Thomas Bagley, Steven M. Babin, Erhan Guven, Teresa K. Yamana, Jeffrey Shaman, Terry Moschou, Nick Lothian, Aaron Lane, Grant Osborne, Gao Jiang, Logan C. Brooks, David C. Farrow, Sangwon Hyun, Ryan J. Tibshirani, Roni Rosenfeld, Justin Lessler, Nicholas G. Reich, Derek A. T. Cummings, Stephen A. Lauer, Sean M. Moore, Hannah E. Clapham, Rachel Lowe, Trevor C. Bailey, Markel García-Díez, Marilia Sá Carvalho, Xavier Rodó, Tridip Sardar, Richard Paul, Evan L. Ray, Krzysztof Sakrejda, Alexandria C. Brown, Xi Meng, Osonde Osoba, Raffaele Vardavas, David Manheim, Melinda Moore, Dhananjai M. Rao, Travis C. Porco, Sarah Ackley, Fengchen Liu, Lee Worden, Matteo Convertino, Yang Liu, Abraham Reddy, Eloy Ortiz, Jorge Rivero, Humberto Brito, Alicia Juarrero, Leah R. Johnson, Robert B. Gramacy, Jeremy M. Cohen, Erin A. Mordecai, Courtney C. Murdock, Jason R. Rohr, Sadie J. Ryan, Anna M. Stewart-Ibarra, Daniel P. Weikel, Antarpreet Jutla, Rakibul Khan, Marissa Poultney, Rita R. Colwell, Brenda Rivera-García, Christopher M. Barker, Jesse E. Bell, Matthew Biggerstaff, David Swerdlow, Luis Mier-y-Teran-Romero, Brett M. Forshey, Juli Trtanj, Jason Asher, Matt Clay, Harold S. Margolis, Andrew M. Hebbeler, Dylan George, and Jean-Paul Chretien, which was first published November 11, 2019; 10.1073/pnas.1909865116. The authors note that the affiliation for Xavier Rodó should instead appear as Catalan Institution for Research and Advanced Studies (ICREA) and Climate and Health Program, Barcelona Institute for Global Health (ISGlobal). The corrected author and affiliation lines appear below. The online version has been corrected.

A wide range of research has promised new tools for forecasting infectious disease dynamics, but little of that research is currently being applied in practice, because tools do not address key public health needs, do not produce probabilistic forecasts, have not been evaluated on external data, or do not provide sufficient forecast skill to be useful. We developed an open collaborative forecasting challenge to assess probabilistic forecasts for seasonal epidemics of dengue, a major global public health problem. Sixteen teams used a variety of methods and data to generate forecasts for 3 epidemiological targets (peak incidence, the week of the peak, and total incidence) over 8 dengue seasons in Iquitos, Peru and San Juan, Puerto Rico. Forecast skill was highly variable across teams and targets. While numerous forecasts showed high skill for midseason situational awareness, early season skill was low, and skill was generally lowest for high incidence seasons, those for which forecasts would be most valuable. A comparison of modeling approaches revealed that average forecast skill was lower for models including biologically meaningful data and mechanisms and that both multimodel and multiteam ensemble forecasts consistently outperformed individual model forecasts. Leveraging these insights, data, and the forecasting framework will be critical to improve forecast skill and the application of forecasts in real time for epidemic preparedness and response. Moreover, key components of this project-integration with public health needs, a common forecasting framework, shared and standardized data, and open participation-can help advance infectious disease forecasting beyond dengue. Published version

Please cite this paper as: Forshey et al. (2010) Epidemiology of influenza‐like illness in the Amazon Basin of Peru, 2008–2009. Influenza and Other Respiratory Viruses 4(4), 235–243. Background Data addressing the incidence and epidemiology of influenza and influenza‐like illness (ILI) in tropical regions of the world is scarce, particularly for the neotropics of South America. Methods We conducted active, population‐based surveillance for ILI across 45 city blocks within the Amazon Basin city of Iquitos, Peru. Demographic data and household characteristics were collected for all participants, and participating households were visited three times weekly to inquire about ILI (fever plus cough or sore throat) among household residents. Nasal and oropharyngeal swabs were collected from participants with ILI and tested for influenza virus infection. Results Between May 1, 2008 and July 8, 2009, we monitored 10,341 participants for ILI for a total of 11 569·5 person‐years. We detected 459 ILI episodes, with 252 (54·9%) of the participants providing specimens. Age‐adjusted incidence of ILI was estimated to be 46·7 episodes/1000 person‐years. Influenza A and B viruses were detected in 25 (9·9%) and 62 (24·6%) specimens of ILI patients, respectively, for an estimated age‐adjusted incidence rate of 16·5 symptomatic influenza virus infections/1000 person‐years. Risk factors for ILI included age, household crowding, and use of wood as cooking fuel. For influenza virus infection specifically, age and use of wood as a cooking fuel were also identified as risk factors, but no effect of household crowding was observed. Conclusions Our results represent the initial population‐based description of the epidemiology of ILI in the Amazon region of Peru, which will be useful for developing region‐specific strategies for reducing the burden of respiratory disease.

El dengue es la arbovirosis más importante del mundo y causa un amplio espectro clínico. Presentamos el primer caso de dengue causado por el serotipo 4 (DENV-4) en Perú con compromiso gastrointestinal (colecistitis aguda alitiásica y hepatitis aguda moderada). Se presenta una revisión de la literatura médica sobre este tipo de presentación, enfatizando la importancia y características del dolor abdominal (hipocondrio derecho), el signo de Murphy, los hallazgos ultrasonográficos y la medición de las enzimas hepáticas para establecer el diagnóstico y manejo adecuado. Dengue fever is the world's most important arboviral disease, presenting a wide clinical spectrum. We report for the first time in Peru, a case caused by dengue virus serotype 4 with significant gastrointestinal involvement (acute acalculous cholecystitis and acute hepatitis). In addition we carried out a review of the literature atypical presentation illustrating the importance of the characteristics of abdominal pain (right upper quadrant); presence of Murphy's sign, ultrasound, and liver enzymes levels, for appropriate diagnosis and clinical management.

BackgroundData addressing the incidence and epidemiology of influenza and influenza-like illness (ILI) in tropical regions of the world is scarce, particularly for the neotropics of South America.MethodsWe conducted active, population-based surveillance for ILI across 45 city blocks within the Amazon Basin city of Iquitos, Peru. Demographic data and household characteristics were collected for all participants, and participating households were visited three times weekly to inquire about ILI (fever plus cough or sore throat) among household residents. Nasal and oropharyngeal swabs were collected from participants with ILI and tested for influenza virus infection.ResultsBetween May 1, 2008 and July 8, 2009, we monitored 10,341 participants for ILI for a total of 11,569.5 person-years. We detected 459 ILI episodes, with 252 (54.9%) of the participants providing specimens. Age-adjusted incidence of ILI was estimated to be 46.7 episodes/1000 person-years. Influenza A and B viruses were detected in 25 (9.9%) and 62 (24.6%) specimens of ILI patients, respectively, for an estimated age-adjusted incidence rate of 16.5 symptomatic influenza virus infections/1000 person-years. Risk factors for ILI included age, household crowding, and use of wood as cooking fuel. For influenza virus infection specifically, age and use of wood as a cooking fuel were also identified as risk factors, but no effect of household crowding was observed.ConclusionsOur results represent the initial population-based description of the epidemiology of ILI in the Amazon region of Peru, which will be useful for developing region-specific strategies for reducing the burden of respiratory disease.

Laboratory diagnosis of dengue virus (DENV) infection including DENV serotyping requires skilled labor and well-equipped settings. DENV NS1 lateral flow rapid test (LFT) provides simplicity but lacks ability to identify serotype. A simple, economical, point-of-care device for serotyping is still needed. We present a gravity driven, smartphone compatible, microfluidic device using microcapillary film (MCF) to perform multiplex serotype-specific immunoassay detection of dengue virus NS1. A novel device–termed Cygnus–with a stackable design allows analysis of 1 to 12 samples in parallel in 40 minutes. A sandwich enzyme immunoassay was developed to specifically detect NS1 of all four DENV serotypes in one 60-μl plasma sample. This test aims to bridge the gap between rapid LFT and laboratory microplate ELISAs in terms of sensitivity, usability, accessibility and speed. The Cygnus NS1 assay was evaluated with retrospective undiluted plasma samples from 205 DENV infected patients alongside 50 febrile illness negative controls. Against the gold standard RT-PCR, clinical sensitivity for Cygnus was 82% in overall (with 78, 78, 80 and 76% for DENV1-4, respectively), comparable to an in-house serotyping NS1 microplate ELISA (82% vs 83%) but superior to commercial NS1-LFT (82% vs 74%). Specificity of the Cygnus device was 86%, lower than that of NS1-microplate ELISA and NS1-LFT (100% and 98%, respectively). For Cygnus positive samples, identification of DENV serotypes DENV2-4 matched those by RT-PCR by 100%, but for DENV1 capillaries false positives were seen, suggesting an improved DENV1 capture antibody is needed to increase specificity. Overall performance of Cygnus showed substantial agreement to NS1-microplate ELISA (κ = 0.68, 95%CI 0.58–0.77) and NS1-LFT (κ = 0.71, 95%CI 0.63–0.80). Although further refinement for DENV-1 NS1 detection is needed, the advantages of multiplexing and rapid processing time, this Cygnus device could deliver point-of-care NS1 antigen testing including serotyping for timely DENV diagnosis for epidemic surveillance and outbreak prediction.