Leveraging multiple data types to estimate the size of the Zika epidemic in the Americas

Cohort study: Neurological and cognitive-behavioral sequelae of acquired Zika virus infection among Nicaraguan children

BACKGROUND

ZIKV has neuroinvasive properties, and in utero exposure can cause birth defects, but little is known about the neurological and neurocognitive impacts of acquired ZIKV infection, particularly in children.

METHODS

We assessed neurological symptoms frequency among ZIKV-infected children within one year after ZIKV infection. Three to 5 years post-infection, these children and a matched group of uninfected children were assessed via questionnaires, neurological exams, and neuropsychological testing to evaluate the association between prior ZIKV infection and subsequent neurological symptoms, and cognitive-behavioral function.

RESULTS

Among 194 ZIKV-infected children, 3 reported asthenia, 4 reported neck pain, and 10 reported back pain within one year post-infection. At follow-up, clinician-observed cranial nerve abnormalities were significantly more common among ZIKV-infected vs. uninfected children (16 vs. 3; p < 0.01), with vestibulocochlear nerve abnormalities observed most frequently. While ZIKV-infected children scored better than uninfected on cognitive measures, this difference was not clinically meaningful.

CONCLUSIONS

Neurological signs, including paresthesia and cranial nerve abnormalities, were observed among ZIKV-infected participants in our study. However, we did not observe a meaningful link between acquired ZIKV infection and subsequent neurological, cognitive, or behavioral outcomes in a representative sample. An exception may be hearing impairment and loss, which should be explored further in future studies.

IMPACT

Neurological symptoms, though rare, were observed and reported more frequently among ZIKV-infected vs. uninfected children. These included: asthenia, neck pain, back pain, paresthesia, and cranial nerve abnormalities. Neurocognitive and behavioral test scores were similar among ZIKV-infected and uninfected children. Our study suggests that ZIKV-infected children should be monitored for neurological symptoms and cranial neuropathy to better understand the full burden of acquired ZIKV infection among children.

Prevalence of urologic sequelae and bladder and bowel dysfunctions in patients with congenital Zika syndrome: A multicenter evaluation of the Zika virus bladder and bowel sequelae assistance network

INTRODUCTION

Neurogenic bladder was first confirmed as a urological sequela of Congenital Zika Syndrome (CZS) in 2018. Further clinical-epidemiological evidence also confirmed neurogenic bowel dysfunction and cryptorchidism. To strengthen the care for these children, the Congenital Zika Virus Bladder and Bowel Sequelae Network (RASZ in Brazilian) was created, including six integrated centers in Brazil. This article represents the initial outcome of the efforts by RASZ.

OBJECTIVE

To evaluate the prevalence of bladder and bowel dysfunction, cryptorchidism and other urological sequelae related to CZS in cohorts attended in six Brazilian states.

STUDY DESIGN

Observational, prospective, multicenter study including children with CZS assisted in one of six RASZ collaborative centers between June 2016 and February 2023. Data were collected from patient's first assessment using the same protocols for urological and bowel evaluation. Categorical variables were analyzed by frequency of occurrence and numerical variables by mean, median, and standard deviation. The study was approved by the Research Ethics Committees of each center, all parents/caregivers provided written informed consent.

RESULTS

The study included 414 children aged 2 months to 7 years (mean 2.77 years, SD 1.73), 227 (54.8 %) were male and 140 (33,8 %) referred urological and bowel symptoms on arrival. Prevalence of both urological and bowel sequelae was 66.7 %, 51 % of children aged 4 years and older had urinary incontinence (UI). UTI was confirmed in 23.4 % (two presented toxemia) and among males, 18.1 % had cryptorchidism. Renal ultrasonography, performed in 186 children, was abnormal in 25 (13.4 %), 7 had hydronephrosis. Among the 287 children who performed urodynamics, 283 (98.6 %) were altered: 232 had a lower bladder capacity, 144 a maximum bladder pressure of ≥40 cm H2O, and 127 did not satisfactorily empty their bladder.

DISCUSSION

A higher prevalence of NLUTD, neurogenic bowel and cryptorchidism was confirmed in children with CZS. Early diagnosis and appropriate treatment, including a multidisciplinary approach, may reduce the risk of UTIs, UI and kidney damage. A limitation of the study was the inability of children to complete the protocol, specifically urodynamic evaluation, and ultrasonography. In both exams, the percentage of abnormal cases was higher than that expected in the normal population.

CONCLUSION

A 66,7 % prevalence of combined urological sequelae and bladder-bowel dysfunction related to CZS was confirmed in patients evaluated in six Brazilian cohorts. The most frequent changes were related to NLUTD, neurogenic bowel, and cryptorchidism. Prevalence may be underestimated due to access restrictions to diagnostic tests.

Shifting patterns of dengue three years after Zika virus emergence in Brazil

In 2015, the Zika virus (ZIKV) emerged in Brazil, leading to widespread outbreaks in Latin America. Following this, many countries in these regions reported a significant drop in the circulation of dengue virus (DENV), which resurged in 2018-2019. We examine age-specific incidence data to investigate changes in DENV epidemiology before and after the emergence of ZIKV. We observe that incidence of DENV was concentrated in younger individuals during resurgence compared to 2013-2015. This trend was more pronounced in Brazilian states that had experienced larger ZIKV outbreaks. Using a mathematical model, we show that ZIKV-induced cross-protection alone, often invoked to explain DENV decline across Latin America, cannot explain the observed age-shift without also assuming some form of disease enhancement. Our results suggest that a sudden accumulation of population-level immunity to ZIKV could suppress DENV and reduce the mean age of DENV incidence via both protective and disease-enhancing interactions.

Zika Virus NS1 Drives Tunneling Nanotube Formation for Mitochondrial Transfer, Enhanced Survival, Interferon Evasion, and Stealth Transmission in Trophoblasts

Zika virus (ZIKV) infection continues to pose a significant public health concern due to limited available preventive measures and treatments. ZIKV is unique among flaviviruses in its vertical transmission capacity (i.e., transmission from mother to fetus) yet the underlying mechanisms remain incompletely understood. Here, we show that both African and Asian lineages of ZIKV induce tunneling nanotubes (TNTs) in placental trophoblasts and multiple other mammalian cell types. Amongst investigated flaviviruses, only ZIKV strains trigger TNTs. We show that ZIKV-induced TNTs facilitate transfer of viral particles, proteins, and RNA to neighboring uninfected cells. ZIKV TNT formation is driven exclusively via its non-structural protein 1 (NS1); specifically, the N-terminal region (50 aa) of membrane-bound NS1 is necessary and sufficient for triggering TNT formation in host cells. Using affinity purification-mass spectrometry of cells infected with wild-type NS1 or non-TNT forming NS1 (pNS1ΔTNT) proteins, we found mitochondrial proteins are dominant NS1-interacting partners, consistent with the elevated mitochondrial mass we observed in infected trophoblasts. We demonstrate that mitochondria are siphoned via TNTs from healthy to ZIKV-infected cells, both homotypically and heterotypically, and inhibition of mitochondrial respiration reduced viral replication in trophoblast cells. Finally, ZIKV strains lacking TNT capabilities due to mutant NS1 elicited a robust antiviral IFN-λ 1/2/3 response, indicating ZIKV's TNT-mediated trafficking also allows ZIKV cell-cell transmission that is camouflaged from host defenses. Together, our findings identify a new stealth mechanism that ZIKV employs for intercellular spread among placental trophoblasts, evasion of antiviral interferon response, and the hijacking of mitochondria to augment its propagation and survival. Discerning the mechanisms of ZIKV intercellular strategies offers a basis for novel therapeutic developments targeting these interactions to limit its dissemination.

Mitigating the effects of climate change on human health with vaccines and vaccinations

Climate change represents an unprecedented threat to humanity and will be the ultimate challenge of the 21st century. As a public health consequence, the World Health Organization estimates an additional 250,000 deaths annually by 2030, with resource-poor countries being predominantly affected. Although climate change's direct and indirect consequences on human health are manifold and far from fully explored, a growing body of evidence demonstrates its potential to exacerbate the frequency and spread of transmissible infectious diseases. Effective, high-impact mitigation measures are critical in combating this global crisis. While vaccines and vaccination are among the most cost-effective public health interventions, they have yet to be established as a major strategy in climate change-related health effect mitigation. In this narrative review, we synthesize the available evidence on the effect of climate change on vaccine-preventable diseases. This review examines the direct effect of climate change on water-related diseases such as cholera and other enteropathogens, helminthic infections and leptospirosis. It also explores the effects of rising temperatures on vector-borne diseases like dengue, chikungunya, and malaria, as well as the impact of temperature and humidity on airborne diseases like influenza and respiratory syncytial virus infection. Recent advances in global vaccine development facilitate the use of vaccines and vaccination as a mitigation strategy in the agenda against climate change consequences. A focused evaluation of vaccine research and development, funding, and distribution related to climate change is required.

Key Residue in the Precursor Region of M Protein Contributes to the Neurovirulence and Neuroinvasiveness of the African Lineage of Zika Virus

The Zika virus (ZIKV) represents an important global health threat due to its unusual association with congenital Zika syndrome. ZIKV strains are phylogenetically grouped into the African and Asian lineages. However, the viral determinants underlying the phenotypic differences between the lineages remain unknown. Here, multiple sequence alignment revealed a highly conserved residue at position 21 of the premembrane (prM) protein, which is glutamic acid and lysine in the Asian and African lineages, respectively. Using reverse genetics, we generated a recombinant virus carrying an E21K mutation based on the genomic backbone of the Asian lineage strain FSS13025 (termed E21K). The E21K mutation significantly increased viral replication in multiple neural cell lines with a higher ratio of M to prM production. Animal studies showed E21K exhibited increased neurovirulence in suckling mice, leading to more severe defects in mouse brains by causing more neural cell death and destruction of hippocampus integrity. Moreover, the E21K substitution enhanced neuroinvasiveness in interferon alpha/beta (IFN-α/β) receptor knockout mice, as indicated by the increased mortality, and enhanced replication in mouse brains. The global transcriptional analysis showed E21K infection profoundly altered neuron development networks and induced stronger antiviral immune response than wild type (WT) in both neural cells and mouse brains. More importantly, the reverse K21E mutation based on the genomic backbone of the African strain MR766 caused less mouse neurovirulence. Overall, our findings support the 21st residue of prM functions as a determinant for neurovirulence and neuroinvasiveness of the African lineage of ZIKV. IMPORTANCE The suspected link of Zika virus (ZIKV) to birth defects led the World Health Organization to declare ZIKV a Public Health Emergency of International Concern. ZIKV has been identified to have two dominant phylogenetic lineages, African and Asian. Significant differences exist between the two lineages in terms of neurovirulence and neuroinvasiveness in mice. However, the viral determinants underlying the phenotypic differences are still unknown. Here, combining reverse genetics, animal studies, and global transcriptional analysis, we provide evidence that a single E21K mutation of prM confers to the Asian lineage strain FSS130125 significantly enhanced replication in neural cell lines and more neurovirulent and neuroinvasiveness phenotypes in mice. Our findings support that the highly conserved residue at position 21 of prM functions as a determinant of neurovirulence and neuroinvasiveness of the African lineage of ZIKV in mice.

Replication in the presence of dengue convalescent serum impacts Zika virus neutralization sensitivity and fitness

Introduction

Flaviviruses like dengue virus (DENV) and Zika virus (ZIKV) are mosquito-borne viruses that cause febrile, hemorrhagic, and neurological diseases in humans, resulting in 400 million infections annually. Due to their co-circulation in many parts of the world, flaviviruses must replicate in the presence of pre-existing adaptive immune responses targeted at serologically closely related pathogens, which can provide protection or enhance disease. However, the impact of pre-existing cross-reactive immunity as a driver of flavivirus evolution, and subsequently the implications on the emergence of immune escape variants, is poorly understood. Therefore, we investigated how replication in the presence of convalescent dengue serum drives ZIKV evolution.

Methods

We used an in vitro directed evolution system, passaging ZIKV in the presence of serum from humans previously infected with DENV (anti-DENV) or serum from DENV-naïve patients (control serum). Following five passages in the presence of serum, we performed next-generation sequencing to identify mutations that arose during passaging. We studied two non-synonymous mutations found in the anti-DENV passaged population (E-V355I and NS1-T139A) by generating individual ZIKV mutants and assessing fitness in mammalian cells and live mosquitoes, as well as their sensitivity to antibody neutralization.

Results and discussion

Both viruses had increased fitness in Vero cells with and without the addition of anti-DENV serum and in human lung epithelial and monocyte cells. In Aedes aegypti mosquitoes-using blood meals with and without anti-DENV serum-the mutant viruses had significantly reduced fitness compared to wild-type ZIKV. These results align with the trade-off hypothesis of constrained mosquito-borne virus evolution. Notably, only the NS1-T139A mutation escaped neutralization, while E-V335I demonstrated enhanced neutralization sensitivity to neutralization by anti-DENV serum, indicating that neutralization escape is not necessary for viruses passaged under cross-reactive immune pressures. Future studies are needed to assess cross-reactive immune selection in humans and relevant animal models or with different flaviviruses.

Guillain-Barré Syndrome Following Zika Virus Infection Is Associated With a Diverse Spectrum of Peripheral Nerve Reactive Antibodies

BACKGROUND AND OBJECTIVES

Recent outbreaks of Zika virus (ZIKV) in South and Central America have highlighted significant neurologic side effects. Concurrence with the inflammatory neuropathy Guillain-Barré syndrome (GBS) is observed in 1:4,000 ZIKV cases. Whether the neurologic symptoms of ZIKV infection are immune mediated is unclear. We used rodent and human live cellular models to screen for anti-peripheral nerve reactive IgG and IgM autoantibodies in the sera of patients with ZIKV with and without GBS.

METHODS

In this study, 52 patients with ZIKV-GBS were compared with 134 ZIKV-infected patients without GBS and 91 non-ZIKV controls. Positive sera were taken forward for target identification by immunoprecipitation and mass spectrometry, and candidate antigens were validated by ELISA and cell-based assays. Autoantibody reactions against glycolipid antigens were also screened on an array.

RESULTS

Overall, IgG antibody reactivities to rat Schwann cells (SCs) (6.5%) and myelinated cocultures (9.6%) were significantly higher, albeit infrequent, in the ZIKV-GBS group compared with all controls. IgM antibody immunoreactivity to dorsal root ganglia neurones (32.3%) and SCs (19.4%) was more frequently observed in the ZIKV-GBS group compared with other controls, whereas IgM reactivity to cocultures was as common in ZIKV and non-ZIKV sera. Strong axonal-binding ZIKV-GBS serum IgG antibodies from 1 patient were confirmed to react with neurofascin 155 and 186. Serum from a ZIKV-infected patient without GBS displayed strong myelin-binding and putative antilipid antigen reaction characteristics. There was, however, no significant association of ZIKV-GBS with any known antiglycolipid antibodies.

DISCUSSION

Autoantibody responses in ZIKV-GBS target heterogeneous peripheral nerve antigens suggesting heterogeneity of the humoral immune response despite a common prodromal infection.

Estimating Zika virus attack rates and risk of Zika virus-associated neurological complications in Colombian capital cities with a Bayesian model

Zika virus (ZIKV) is a mosquito-borne pathogen that caused a major epidemic in the Americas in 2015-2017. Although the majority of ZIKV infections are asymptomatic, the virus has been associated with congenital birth defects and neurological complications (NC) in adults. We combined multiple data sources to improve estimates of ZIKV infection attack rates (IARs), reporting rates of Zika virus disease (ZVD) and the risk of ZIKV-associated NC for 28 capital cities in Colombia. ZVD surveillance data were combined with post-epidemic seroprevalence data and a dataset on ZIKV-associated NC in a Bayesian hierarchical model. We found substantial heterogeneity in ZIKV IARs across cities. The overall estimated ZIKV IAR across the 28 cities was 0.38 (95% CrI: 0.17-0.92). The estimated ZVD reporting rate was 0.013 (95% CrI: 0.004-0.024), and 0.51 (95% CrI: 0.17-0.92) cases of ZIKV-associated NC were estimated to be reported per 10 000 ZIKV infections. When we assumed the same ZIKV IAR across sex or age group, we found important spatial heterogeneities in ZVD reporting rates and the risk of being reported as a ZVD case with NC. Our results highlight how additional data sources can be used to overcome biases in surveillance data and estimate key epidemiological parameters.

Eeyarestatin I, an inhibitor of the valosin-containing protein, exhibits potent virucidal activity against the flaviviruses

Cellular responses to stress generally lead to the activation of the endoplasmic reticulum-associated protein degradation (ERAD) pathway. Several lines of study support that ERAD may be playing a proviral role during flaviviral infection. A key host factor in ERAD is the valosin-containing protein (VCP), an ATPase which ushers ubiquitin-tagged proteins to degradation by the proteasome. VCP exhibits different proviral activities, such as engaging in the biogenesis of viral replication organelles and facilitating flavivirus genome uncoating after the viral particle entry. To investigate the possible antiviral value of drugs targeting VCP, we tested two inhibitors: eeyarestatin I (EEY) and xanthohumol (XAN). Both compounds were highly effective in suppressing Zika virus (ZIKV) and Usutu virus (USUV) replication during infection in cell culture. Further analysis revealed an unexpected virucidal activity for EEY, but not for XAN. Preincubation of ZIKV or USUV with EEY before inoculation to cells resulted in significant decreases in infectivity in a dose- and time-dependent manner. Viral genomes in samples previously treated with EEY were more sensitive to propidium monoazide, an intercalating agent, with 10- to 100-fold decreases observed in viral RNA levels, supporting that EEY affects viral particle integrity. Altogether, these results support that EEY is a strong virucide against two unrelated flaviviruses, encouraging further studies to investigate its potential use as a broad-acting drug or the development of improved derivatives in the treatment of flaviviral infection.

The Remote Emerging Disease Intelligence-NETwork

Accurate prediction of zoonotic spillover events requires a detailed understanding of baseline pathogens circulating in differing global environments. By characterizing the diversity and determining the natural baseline of pathogens in a given biological system, any perturbations to this balance can be detected, leading to estimates of risk for emerging diseases. As epidemics and probability for pandemics increase, there is a fundamental need for building global collaborations to fill gaps in the surveillance effort, especially to build remote in-county capacity and standardize timely sample processing and data analysis. To this point, a new consortium, the Remote Emerging Disease Intelligence-NETwork (REDI-NET) has been established to enhance surveillance approaches and characterize natural pathogens in temperate, tropical forest, and tropical grassland biomes. The REDI-NET is envisioned to be a long-term, phased initiative. All phases will integrate accompanying training resources such as videos reflecting SOPs and Quick Reference Guides. Routine bio- and xenosurveillance will facilitate the characterization of ecological parameters, enhance the accuracy of vector species identification using artificial intelligence technology, and guide the establishment of epidemiological risk thresholds critical for mitigating disease outbreaks in a timely manner. A key deliverable of the REDI-NET is a custom-designed electronically merged (e-MERGE) data pipeline and alert dashboard that integrates remotely captured data with state-of-the-art metagenomic next-generation sequencing technology. This pipeline incorporates data generated from field and laboratory best practices, to furnish health decision-makers with a centralized, timely, and rigorous database to efficiently search interdisciplinary and heterogeneous data sources necessary to alert, prepare and mitigate health threats. The e-MERGE pipeline, once fully established, will be a flexible, scalable, and expandable tool for varied health applications. Program success will result in an operational framework that addresses resource gaps in pathogen surveillance and enhances health protection with broad global applicability. The objective of this manuscript is to introduce the REDI-NET framework to anticipated stakeholders engaged in metagenomics, epidemiological surveillance, and One Health with a focus on Phase 1.

Zika Virus after the Public Health Emergency of International Concern Period, Brazil

More than 100,000 Zika virus cases have been reported in Brazil since the Public Health Emergency of International Concern period ended in 2016. We analyzed cases in Brazil during 2017–2021 to identify transmission trends and forecast future infection hotspots. Our results can be used for targeted interventions to reduce transmission.

Zika Virus Antibody Titers Three Years after Confirmed Infection

Background: In 2015–2016, a large Zika virus (ZIKV) outbreak occurred in the Americas. Although the exact ZIKV antibody kinetics after infection are unknown, recent evidence indicates the rapid waning of ZIKV antibodies in humans. Therefore, we aimed to determine the levels of ZIKV antibodies more than three years after a ZIKV infection. Methods: We performed ZIKV virus neutralization tests (VNT) and a commercial ZIKV non-structural protein 1 (NS1) IgG ELISA in a cohort of 49 participants from Suriname who had a polymerase-chain-reaction-confirmed ZIKV infection more than three years ago. Furthermore, we determined the presence of antibodies against multiple dengue virus (DENV) antigens. Results: The ZIKV seroprevalence in this cohort, assessed with ZIKV VNT and ZIKV NS1 IgG ELISA, was 59.2% and 63.3%, respectively. There was, however, no correlation between these two tests. Furthermore, we did not find evidence of a potential negative influence of DENV immunity on ZIKV antibody titers. Conclusions: ZIKV seroprevalence, assessed with two commonly used serological tests, was lower than expected in this cohort of participants who had a confirmed previous ZIKV infection. This can have implications for future ZIKV seroprevalence studies and possibly for the duration of immunological protection after a ZIKV infection.

Experimental infections with Zika virus strains reveal high vector competence of Aedes albopictus and Aedes aegypti populations from Gabon (Central Africa) for the African virus lineage

The two main Zika virus (ZIKV) vectors, Aedes albopictus and Aedes aegypti (invasive and native species, respectively), are present in Gabon (Central Africa). The aim of this study was to determine the entomological ZIKV risk associated with these mosquito species in Gabon by evaluating their vector competence for an African (i.e. representative of the endemic strains circulating in sub-Saharan Africa) and two Asian (i.e. representatives of exogenous epidemic strains that could be introduced) ZIKV strains. The transmission efficiency of one Ae. aegypti and two Ae. albopictus field-collected populations from Libreville and Franceville was assayed at day 7, 14 and 21 after experimental oral infection. The two mosquito species could transmit all three ZIKV strains already at day 7 post-infection, but transmission efficiency was higher for the African strain than the non-African strains (>60% versus <14%; incubation period of 14–21 days). The two mosquito species exhibited comparable vector competence for ZIKV, although the amount of viral particles (African strain) in saliva was significantly higher in Ae. albopictus than Ae. aegypti at day 14 post-infection. These findings suggest that overall, ZIKV risk in Gabon is mainly related to virus strains that circulate endemically across sub-Saharan Africa, although the transmission of non-African strains remain possible in case of introduction. Due to its high infestation indexes and ecological/geographical ranges, this risk appears mainly associated with Ae. albopictus. Vector surveillance and control methods against this invasive mosquito must be strengthened in the region to limit the risk of future outbreaks.

Estimating incidence of infection from diverse data sources: Zika virus in Puerto Rico, 2016

Emerging epidemics are challenging to track. Only a subset of cases is recognized and reported, as seen with the Zika virus (ZIKV) epidemic where large proportions of infection were asymptomatic. However, multiple imperfect indicators of infection provide an opportunity to estimate the underlying incidence of infection. We developed a modeling approach that integrates a generic Time-series Susceptible-Infected-Recovered epidemic model with assumptions about reporting biases in a Bayesian framework and applied it to the 2016 Zika epidemic in Puerto Rico using three indicators: suspected arboviral cases, suspected Zika-associated Guillain-Barré Syndrome cases, and blood bank data. Using this combination of surveillance data, we estimated the peak of the epidemic occurred during the week of August 15, 2016 (the 33^rd week of year), and 120 to 140 (50% credible interval [CrI], 95% CrI: 97 to 170) weekly infections per 10,000 population occurred at the peak. By the end of 2016, we estimated that approximately 890,000 (95% CrI: 660,000 to 1,100,000) individuals were infected in 2016 (26%, 95% CrI: 19% to 33%, of the population infected). Utilizing multiple indicators offers the opportunity for real-time and retrospective situational awareness to support epidemic preparedness and response.

Zika virus (ZIKV) infections, like many infections, are generally underreported due to asymptomatic, mild, or unrecognized cases. Using available surveillance indicators reflecting imperfect proxies of infection, we developed a modeling approach to estimate the weekly incidence of infection by combining independent surveillance indicators and assumptions about system-specific reporting biases in a Bayesian framework. Using our approach, we estimated that approximately 890,000 people in the population were infected with Zika in Puerto Rico in 2016, much higher than the 36,316 reported confirmed infections. Our framework has broad application to other diseases where cases may be underreported through traditional disease surveillance and can provide near real-time changes in incidences.

Publication Trends in Neglected Tropical Diseases of Latin America and the Caribbean: A Bibliometric Analysis

(1) Background: Neglected tropical diseases (NTDs) have been overlooked on the global health agenda and in the priorities of national systems in low- and middle-income countries (LMICs). In 2012, the Sustainable Development Goals (SDGs) were created to ensure healthy lives and promoting well-being for all. This roadmap set out to accelerate work to overcome the global impact of NTDs. Almost a decade has passed since NTDs were re-launched as a global priority. Investment in research and development, as well as the production of scientific literature on NTDs, is expected to have increased significantly. (2) Methods: A bibliometric analysis of the scientific production of Latin America and the Caribbean (LAC) was carried out in relation to 19 endemic NTDs. These data were compared with the scientific production in malaria, tuberculosis, and HIV/AIDS. The database available from Thomson Reuters Web of Science (WoS) was used. In addition, the average annual growth percentage was calculated for each disease. (3) Results: In the last decade, the NTDs with the highest number of publications in the world were dengue and leishmaniasis. The United States was the most prolific country in the world in 15 out of 19 NTDs analyzed. In the LAC region, Brazil was the largest contributor for 16 of the 19 NTDs analyzed. Arboviral diseases showed the highest average annual growth. The number of publications for malaria, tuberculosis and HIV/AIDS was considerably higher than for NTDs. The contribution of most LAC countries, especially those considered to be LMICs, is inadequate and does not reflect the relevance of NTDs for the public health of the population. (4) Conclusions: This is the first bibliometric analysis to assess the trend of scientific documents on endemic NTDs in LAC. Our results could be used by decision makers both to strengthen investment policies in research and development in NTDs.

Co-circulation and misdiagnosis led to underestimation of the 2015-2017 Zika epidemic in the Americas

During the 2015-2017 Zika epidemic, dengue and chikungunya-two other viral diseases with the same vector as Zika-were also in circulation. Clinical presentation of these diseases can vary from person to person in terms of symptoms and severity, making it difficult to differentially diagnose them. Under these circumstances, it is possible that numerous cases of Zika could have been misdiagnosed as dengue or chikungunya, or vice versa. Given the importance of surveillance data for informing epidemiological analyses, our aim was to quantify the potential extent of misdiagnosis during this epidemic. Using basic principles of probability and empirical estimates of diagnostic sensitivity and specificity, we generated revised estimates of reported cases of Zika that accounted for the accuracy of diagnoses made on the basis of clinical presentation with or without laboratory confirmation. Applying this method to weekly reported case data from 43 countries throughout Latin America and the Caribbean, we estimated that 944,700 (95% CrI: 884,900-996,400) Zika cases occurred when assuming all confirmed cases were diagnosed using molecular methods versus 608,400 (95% CrI: 442,000-821,800) Zika cases that occurred when assuming all confirmed cases were diagnosed using serological methods. Our results imply that misdiagnosis was more common in countries with proportionally higher reported cases of dengue and chikungunya, such as Brazil. Given that Zika, dengue, and chikungunya appear likely to co-circulate in the Americas and elsewhere for years to come, our methodology has the potential to enhance the interpretation of passive surveillance data for these diseases going forward. Likewise, our methodology could also be used to help resolve transmission dynamics of other co-circulating diseases with similarities in symptomatology and potential for misdiagnosis.