Broad protection and respiratory immunity of dual mRNA vaccination against SARS-CoV-2 variants.

While first-generation, spike (S)-based COVID-19 vaccines were effective against early SARS-CoV-2 strains, the rapid evolution of novel Omicron subvariants have substantially reduced vaccine efficacy. As such, broadly protective vaccines against SARS-CoV-2 are needed to prevent future viral emergence. In addition, it remains less clear whether peripheral immunization, especially with mRNA vaccines, elicits effective respiratory immunity. Our group has developed a nucleoside-modified mRNA vaccine expressing the nucleocapsid (N) protein of the ancestral SARS-CoV-2 virus and has tested its use in combination with the S-based mRNA vaccine (mRNA-S). In this study, we examined efficacy of mRNA-N alone or in combination with mRNA-S (mRNA-S+N) against more immune evasive Omicron variants in hamsters. Our data show that mRNA-N alone induces a modest but significant protection against BA.5 and that dual mRNA-S+N vaccination confers complete protection against both BA.5 and BQ.1, preventing detection of virus in the hamster lungs. Analysis of respiratory immune response in mice shows that intramuscular mRNA-S+N immunization effectively induces respiratory S- and N-specific T cell responses in the lungs and in bronchoalveolar lavage (BAL), as well as antigen-specific binding IgG in BAL. Together, our data further support mRNA-S+N as a potential pan-COVID-19 vaccine for broad protection against current and emerging SARS-CoV-2 variants.

Using one health training for interprofessional team building: implications for research, policy, and practice in Nigeria.

In recent years, the concept of One Health (OH) has arisen as an approach that helps to catalyze the creation of transdisciplinary teams needed for surveillance and investigation of emerging disease dynamics. Besides a wealth of descriptions of what the OH approach encompasses, a dearth of information is available regarding the training of individuals in OH competencies. In 2019, the Nigerian Center for Disease Control developed an OH strategic plan to meet the country's human, animal, and environmental health challenges. In response to the demand for clinicians, scientists, climatologists, conservationists, and environmentalists, who have expertise in environment, human, plant, and animal health to work collaboratively in addressing OH challenges in Nigeria. An interprofessional group of faculty from the University of Texas Medical Branch, the University of Jos, and the National Veterinary Research Institute convened to develop a novel OH course 'entitled 'One Health for Translational Team Science. The objective of the course was to explore the evolution of an emerging epidemic, capitalizing on various learning environments, including animal, environmental, human, and public health perspectives. The 6-week course comprised of three parts: 2-weeks virtual part of case-based group discussions focusing on animal and environmental aspects, 2 weeks of individual field experiences, and a final virtual part focusing on human health. Pedagogical tools used were: case-based group discussions, breakout group presentations, role-play activities, field project write-up, peer evaluation, group writing assignments, and weekly reflections with the goal of working in teams to develop and practice the fundamental leadership and management skills in addressing emerging public health challenges. Post-course evaluations showed that all participants felt more confident identifying and practicing the necessary attitudes and skills to participate effectively in the evaluation of an outbreak. Furthermore, the roles, responsibilities, and "One Health ways of thinking" for the various disciplines and professions involved in improving global health were articulated and identified.

Reemergence of Oropouche virus between 2023 and 2024 in Brazil.

Background: Oropouche virus (OROV; species Orthobunyavirus oropoucheense) is an arthropod-borne virus that has caused outbreaks of Oropouche fever in Central and South America since the 1950s. This study investigates virological factors contributing to the reemergence of Oropouche fever in Brazil between 2023 and 2024. Methods: In this study, we combined OROV genomic, molecular, and serological data from Brazil from 1 January 2015 to 29 June 2024, along with in vitro and in vivo characterization. Molecular screening data included 93 patients with febrile illness between January 2023 and February 2024 from the Amazonas State. Genomic data comprised two genomic OROV sequences from patients. Serological data were obtained from neutralizing antibody tests comparing the prototype OROV strain BeAn 19991 and the 2024 epidemic strain. Epidemiological data included aggregated cases reported to the Brazilian Ministry of Health from 1 January 2014 to 29 June 2024. Findings: In 2024, autochthonous OROV infections were detected in previously non-endemic areas across all five Brazilian regions. Cases were reported in 19 of 27 federal units, with 83.2% (6,895 of 8,284) of infections in Northern Brazil and a nearly 200-fold increase in incidence compared to reported cases over the last decade. We detected OROV RNA in 10.8% (10 of 93) of patients with febrile illness between December 2023 and May 2024 in Amazonas. We demonstrate that the 2023-2024 epidemic was caused by a novel OROV reassortant that replicated approximately 100-fold higher titers in mammalian cells compared to the prototype strain. The 2023-2024 OROV reassortant displayed plaques earlier than the prototype, produced 1.7 times more plaques, and plaque sizes were 2.5 larger compared to the prototype. Furthermore, serum collected in 2016 from previously OROV-infected individuals showed at least a 32-fold reduction in neutralizing capacity against the reassortment strain compared to the prototype. Interpretation: These findings provide a comprehensive assessment of Oropouche fever in Brazil and contribute to a better understanding of the 2023-2024 OROV reemergence. The recent increased incidence may be related to a higher replication efficiency of a new reassortant virus that also evades previous immunity.

Molecular Epidemiology of Western Equine Encephalitis Virus, South America, 2023-2024.

Western equine encephalitis virus (WEEV) is a mosquitoborne virus that reemerged in December 2023 in Argentina and Uruguay, causing a major outbreak. We investigated the outbreak using epidemiologic, entomological, and genomic analyses, focusing on WEEV circulation near the Argentina‒Uruguay border in Rio Grande do Sul state, Brazil. During November 2023‒April 2024, the outbreak in Argentina and Uruguay resulted in 217 human cases, 12 of which were fatal, and 2,548 equine cases. We determined cases on the basis of laboratory and clinical epidemiologic criteria. We characterized 3 fatal equine cases caused by a novel WEEV lineage identified through a nearly complete coding sequence analysis, which we propose as lineage C. Our findings highlight the importance of continued surveillance and equine vaccination to control future WEEV outbreaks in South America.

Double stigma: a cross-sectional study of Lassa patients with hearing loss in North Central Nigeria.

Introduction: Lassa fever is a zoonotic infectious disease endemic in West Africa with a high case-fatality rate and reported stigmatization of surviving patients. This study examines discrimination among survivors of Lassa fever (LF) complicated by hearing loss (HL). Methods: This cross-sectional qualitative study used an in-depth interview guide to collect information from patients with HL about their experience of stigma. Interviews were conducted by a trained team of interviewers at the Jos University Teaching Hospital between January and April 2022 in Hausa language after informed consent was obtained. Recordings of the interviews were transcribed and translated from Hausa to English. Data analysis was conducted using NVivo software using a thematic framework approach. Results: Most (73%) respondents were male (n = 11); 27% were female (n = 4). The median age was 35 years (interquartile range, 16.5). Some Lassa fever patients experienced stigma and discrimination (53%) including isolation and withdrawal of family and community support during and after illness. HL increased stigma, as some patients were labeled "deaf" by other community members, increasing perceived stigma and devaluation. HL affected the socio-economic wellbeing of some who could not communicate well with their families and customers and constrained social interactions, evoking pain and apathy. Some survivors of LF and victims of its sequelae of HL experienced double stigmatization. While they were ill with LF, a third of respondents reported avoidance and isolation by family and community members who withdrew care and support both to them and their close family members. These forms of stigmatization strained their relationships. Conclusion: There is a need to address stigma in LF survivors who develop HL through concerted community-owned awareness to improve their quality of life along with a robust social support system to aid prevention.

Establishment of a multisite umbrella cohort study protocol to describe the epidemiology and aetiologies of acute undifferentiated febrile illness in Latin America.

INTRODUCTION: Acute undifferentiated febrile illnesses (AUFIs) impose a large burden in the tropics. Understanding of AUFI's epidemiology is limited. Insufficient diagnostic capacity hinders the detection of outbreaks. The lack of interconnection in healthcare systems hinders timely response. We describe a protocol to study the epidemiology and aetiologies of AUFI and pathogen discovery in strategic areas of Latin America (LA). METHODS AND ANALYSIS: Global Infectious Diseases Network investigators comprising institutions in Colombia, Dominican Republic, México, Perú and the USA, developed a common cohort study protocol. The primary objective is to determine the aetiologies of AUFI at healthcare facilities in high-risk areas. Data collection and laboratory testing for viral, bacterial and parasitic agents are performed in rural and urban healthcare facilities and partner laboratories. Centralised laboratory and data management cores deploy diagnostic tests and data management tools. Subjects >6 years with fever for <8 days without localised infection are included in the cohort. They are evaluated during the acute and convalescent phases of illness. Study personnel collect clinical and epidemiological information. Blood, urine, nasal or pharyngeal swabs and saliva are collected in the acute phase and blood in convalescent phase. Specimens are banked at -80°C. Malaria, dengue and COVID-19 are tested onsite in the acute phase. The acute-phase serum is PCR tested for dengue, chikungunya, Venezuelan equine encephalitis, Mayaro, Oropouche, Zika, and yellow fever viruses. Paired convalescent and acute serum antibody titters are tested for arbovirus, Leptospira spp, and Rickettsia spp. Serum is used for viral cultures and next-generation sequencing for pathogen discovery. Analysis includes variable distributions, risk factors and regression models. Laboratory results are shared with health authorities and network members. ETHICS AND DISSEMINATION: The protocol was approved by local ethics committees and health authorities. The results will be published in peer-reviewed journals. All study results are shared with local and regional health authorities.

Shifts in receptors during submergence of an encephalitic arbovirus.

Western equine encephalitis virus (WEEV) is an arthropod-borne virus (arbovirus) that frequently caused major outbreaks of encephalitis in humans and horses in the early twentieth century, but the frequency of outbreaks has since decreased markedly, and strains of this alphavirus isolated in the past two decades are less virulent in mammals than strains isolated in the 1930s and 1940s1-3. The basis for this phenotypic change in WEEV strains and coincident decrease in epizootic activity (known as viral submergence3) is unclear, as is the possibility of re-emergence of highly virulent strains. Here we identify protocadherin 10 (PCDH10) as a cellular receptor for WEEV. We show that multiple highly virulent ancestral WEEV strains isolated in the 1930s and 1940s, in addition to binding human PCDH10, could also bind very low-density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (ApoER2), which are recognized by another encephalitic alphavirus as receptors4. However, whereas most of the WEEV strains that we examined bind to PCDH10, a contemporary strain has lost the ability to recognize mammalian PCDH10 while retaining the ability to bind avian receptors, suggesting WEEV adaptation to a main reservoir host during enzootic circulation. PCDH10 supports WEEV E2-E1 glycoprotein-mediated infection of primary mouse cortical neurons, and administration of a soluble form of PCDH10 protects mice from lethal WEEV challenge. Our results have implications for the development of medical countermeasures and for risk assessment for re-emerging WEEV strains.

Genomic characterization of a reemerging Chikungunya outbreak in Kedougou, Southeastern Senegal, 2023.

Chikungunya virus has caused millions of cases worldwide over the past 20 years, with recent outbreaks in Kedougou region in the southeastern Senegal, West Africa. Genomic characterization highlights that an ongoing epidemic in Kedougou in 2023 is not due to an introduction event but caused by the re-emergence of an endemic strain evolving linearly in a sylvatic context.

A VHH single-domain platform enabling discovery and development of monospecific antibodies and modular neutralizing bispecifics against SARS-CoV-2 variants.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, escape coronavirus disease 2019 therapeutics and vaccines, and jeopardize public health. To combat SARS-CoV-2 antigenic escape, we developed a rapid, high-throughput pipeline to discover monospecific VHH antibodies and iteratively develop VHH-Fc-VHH bispecifics capable of neutralizing emerging SARS-CoV-2 variants. By panning VHH single-domain phage libraries against ancestral or beta spike proteins, we discovered high-affinity VHH antibodies with unique target epitopes. Combining two VHHs into a tetravalent bispecific construct conferred broad neutralization activity against multiple variants and was more resistant to antigenic escape than the monospecific antibody alone. Following the rise of the Omicron variant, a VHH in the original bispecific construct was replaced with another VHH discovered against the Omicron BA.1 receptor binding domain; the resulting bispecific exhibited neutralization against both BA.1 and BA.5 sublineage variants. A heavy chain-only tetravalent VHH-Fc-VHH bispecific platform derived from humanized synthetic libraries held a myriad of unique advantages: (i) synthetic preconstructed libraries minimized risk of liabilities and maximized discovery speed, (ii) VHH scaffolds allowed for a modular "plug-and-play" format that could be rapidly iterated upon as variants of concern arose, (iii) natural dimerization of single VHH-Fc-VHH polypeptides allowed for straightforward bispecific production and purification methods, and (iv) multivalent approaches enhanced avidity boosting effects and neutralization potency, and conferred more robust resistance to antigenic escape than monovalent approaches against specific variants. This iterative platform of rapid VHH discovery combined with modular bispecific design holds promise for long-term viral control efforts.

Mechanisms of Flavivirus Cross-Protection against Yellow Fever in a Mouse Model.

The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector Aedes (Stegomyia.) aegypti is an enigma. An immunologically naïve population of over 2 billion resides in Asia, with most regions infested with the urban YF vector. One hypothesis for the lack of Asian YF, and absence of urban YF in the Americas for over 80 years, is that prior immunity to related flaviviruses like dengue (DENV) or Zika virus (ZIKV) modulates YFV infection and transmission dynamics. Here we utilized an interferon α/ß receptor knock-out mouse model to determine the role of pre-existing dengue-2 (DENV-2) and Zika virus (ZIKV) immunity in YF virus infection, and to determine mechanisms of cross-protection. We utilized African and Brazilian YF strains and found that DENV-2 and ZIKV immunity significantly suppresses YFV viremia in mice, but may or may not protect relative to disease outcomes. Cross-protection appears to be mediated mainly by humoral immune responses. These studies underscore the importance of re-assessing the risks associated with YF outbreak while accounting for prior immunity from flaviviruses that are endemic.

Results of a nationally representative seroprevalence survey of chikungunya virus in Bangladesh.

There is an increasing global burden from chikungunya virus (CHIKV). Bangladesh reported a major epidemic in 2017, however, it was unclear if there had been prior widespread transmission. We conducted a nationally representative seroprevalence survey in 70 randomly selected communities immediately prior to the epidemic. We found 69/2,938 (2.4%) of sampled individuals were seropositive to CHIKV. Being seropositive to dengue virus (aOR 3.13 [95% CIs: 1.86-5.27]), male sex (aOR 0.59 [95% CIs: 0.36-0.99]), and community presence of Aedes aegypti mosquitoes (aOR: 1.80, 95% CI: 1.05-3.07) were significantly associated with CHIKV seropositivity. Using a spatial prediction model, we estimated that across the country, 4.99 (95% CI: 4.89 - 5.08) million people had been previously infected. These findings highlight high population susceptibility prior to the major outbreak and that previous outbreaks must have been spatially isolated.

A safe insect-based Chikungunya fever vaccine affords rapid and durable protection in cynomolgus macaques.

Chikungunya virus (CHIKV), which induces chikungunya fever and chronic arthralgia, is an emerging public health concern. Safe and efficient vaccination strategies are needed to prevent or mitigate virus-associated acute and chronic morbidities for preparation of future outbreaks. Eilat (EILV)/CHIKV, a chimeric alphavirus which contains the structural proteins of CHIKV and the non-structural proteins of EILV, does not replicate in vertebrate cells. The chimeric virus was previously reported to induce protective adaptive immunity in mice. Here, we assessed the capacity of the virus to induce quick and durable protection in cynomolgus macaques. EILV/CHIKV protected macaques from wild-type (WT) CHIKV infection one year after a single dose vaccination. Transcriptome and in vitro functional analyses reveal that the chimeric virus triggered toll-like receptor signaling and T cell, memory B cell and antibody responses in a dose-dependent manner. Notably, EILV/CHIKV preferentially induced more durable, robust, and broader repertoire of CHIKV-specific T cell responses, compared to a live attenuated CHIKV 181/25 vaccine strain. The insect-based chimeric virus did not cause skin hypersensitivity reactions in guinea pigs sensitized to mosquito bites. Furthermore, EILV/CHIKV induced strong neutralization antibodies and protected cynomolgus macaques from WT CHIKV infection within six days post vaccination. Transcriptome analysis also suggest that the chimeric virus induction of multiple innate immune pathways, including Toll-like receptor signaling, type I IFN and IL-12 signaling, antigen presenting cell activation, and NK receptor signaling. Our findings suggest that EILV/CHIKV is a safe, highly efficacious vaccine, and provides both rapid and long-lasting protection in cynomolgus macaques.

Serosurvey of Chikungunya Virus in Old World Fruit Bats, Senegal, 2020-2022.

We conducted a cross-sectional serosurvey for chikungunya virus (CHIKV) exposure in fruit bats in Senegal during 2020-2023. We found that 13.3% (89/671) of bats had CHIKV IgG; highest prevalence was in Eidolon helvum (18.3%, 15/82) and Epomophorus gambianus (13.7%, 63/461) bats. Our results suggest these bats are naturally exposed to CHIKV.

Prevalence and associated factors of shisha smoking among students in Senegal: Global Youth Tobacco Survey 2020.

INTRODUCTION: Although shisha smoking is banned in Senegal, it has become increasingly popular, especially among youth. Despite the health risks associated with shisha smoking, there are few studies on shisha smoking in West Africa and none in Senegal. Our study assessed the prevalence and factors associated with shisha smoking among students aged 13-15 years in Senegal. METHODS: We used the 2020 Global Youth Tobacco Survey (GYTS) Senegal data from 2524 students aged 13-15 years. We calculated the weighted prevalence of ever and current (past 30 days) shisha smoking. Multivariable logistic regression analyses identified factors associated with ever and current shisha smoking among students. RESULTS: The prevalences of ever and current shisha smoking were 9.8% (95% CI: 7.7-12.3) and 2.2% (95% CI: 1.5-3.1), respectively. Ever shisha smoking was significantly associated with being male (AOR=1.97; 95% CI: 1.33-2.92), current cigarette smoking (AOR=7.54; 95% CI: 2.95-19.29), higher class grade (AOR=2.27; 95% CI:1.10-4.67), more weekly pocket money (AOR=3.29; 95% CI:1.36-7.95), current use of smokeless tobacco (AOR=11.53; 95% CI: 4.98- 26.72), and exposure to secondhand cigarette smoke in public (AOR=1.55; 95% CI: 1.00-2.41). Current shisha smoking was significantly associated with current cigarette smoking (AOR=21.75; 95% CI: 6.08-77.78), more weekly pocket money (AOR=8.91; 95% CI: 1.75-45.40), current use of smokeless tobacco (AOR=8.26; 95% CI: 2.07-33.04), and fathers' smoking (AOR=3.34; 95% CI: 1.24-8.96). CONCLUSIONS: One in 10 students aged 13-15 years have ever smoked shisha and 2.2% were currently smoking it, suggesting that shisha smoking is a public health concern in Senegal. Senegal might consider offering students more education on the harms of shisha, both in schools and through comprehensive media campaigns that address all tobacco products.

Molecular epidemiology of Western equine encephalitis virus in Brazil, 2023-2024.

During the ongoing western equine encephalitis virus (WEEV) outbreak in South America, we described three fatal cases in horses from Rio Grande do Sul, Brazil. We sequenced WEEV strains and identified a novel lineage causing these cases. Continued surveillance and horse immunization are needed to mitigate the WEEV burden.

Molecular Epidemiology of Mayaro Virus among Febrile Patients, Roraima State, Brazil, 2018-2021.

We detected Mayaro virus (MAYV) in 3.4% (28/822) of febrile patients tested during 2018-2021 from Roraima State, Brazil. We also isolated MAYV strains and confirmed that these cases were caused by genotype D. Improved surveillance is needed to better determine the burden of MAYV in the Amazon Region.

Effects of climate change and human activities on vector-borne diseases.

Vector-borne diseases are transmitted by haematophagous arthropods (for example, mosquitoes, ticks and sandflies) to humans and wild and domestic animals, with the largest burden on global public health disproportionately affecting people in tropical and subtropical areas. Because vectors are ectothermic, climate and weather alterations (for example, temperature, rainfall and humidity) can affect their reproduction, survival, geographic distribution and, consequently, ability to transmit pathogens. However, the effects of climate change on vector-borne diseases can be multifaceted and complex, sometimes with ambiguous consequences. In this Review, we discuss the potential effects of climate change, weather and other anthropogenic factors, including land use, human mobility and behaviour, as possible contributors to the redistribution of vectors and spread of vector-borne diseases worldwide.

Reemergence of Sylvatic Dengue Virus Serotype 2 in Kedougou, Senegal, 2020.

In 2020, a sylvatic dengue virus serotype 2 infection outbreak resulted in 59 confirmed dengue cases in Kedougou, Senegal, suggesting those strains might not require adaptation to reemerge into urban transmission cycles. Large-scale genomic surveillance and updated molecular diagnostic tools are needed to effectively prevent dengue virus infections in Senegal.

Potential of Ilhéus virus to emerge.

Ilhéus virus (ILHV)(Flaviviridae:Orthoflavivirus) is an arthropod-borne virus (arbovirus) endemic to Central and South America and the Caribbean. First isolated in 1944, most of our knowledge derives from surveillance and seroprevalence studies. These efforts have detected ILHV in a broad range of mosquito and vertebrate species, including humans, but laboratory investigations of pathogenesis and vector competence have been lacking. Here, we develop an immune intact murine model with several ages and routes of administration. Our model closely recapitulates human neuroinvasive disease with ILHV strain- and mouse age-specific virulence, as well as a uniformly lethal Ifnar-/- A129 immunocompromised model. Replication kinetics in several vertebrate and invertebrate cell lines demonstrate that ILHV is capable of replicating to high titers in a wide variety of potential host and vector species. Lastly, vector competence studies provide strong evidence for efficient infection of and potential transmission by Aedes species mosquitoes, despite ILHV's phylogenetically clustering with Culex vectored flaviviruses, suggesting ILHV is poised for emergence in the neotropics.