Mixed-methods protocol for the WiSSPr study: Women in Sex work, Stigma and psychosocial barriers to Pre-exposure prophylaxis in Zambia.

INTRODUCTION: Women engaging in sex work (WESW) have 21 times the risk of HIV acquisition compared with the general population. However, accessing HIV pre-exposure prophylaxis (PrEP) remains challenging, and PrEP initiation and persistence are low due to stigma and related psychosocial factors. The WiSSPr (Women in Sex work, Stigma and PrEP) study aims to (1) estimate the effect of multiple stigmas on PrEP initiation and persistence and (2) qualitatively explore the enablers and barriers to PrEP use for WESW in Lusaka, Zambia. METHODS AND ANALYSIS: WiSSPr is a prospective observational cohort study grounded in community-based participatory research principles with a community advisory board (CAB) of key population (KP) civil society organi sations (KP-CSOs) and the Ministry of Health (MoH). We will administer a one-time psychosocial survey vetted by the CAB and follow 300 WESW in the electronic medical record for three months to measure PrEP initiation (#/% ever taking PrEP) and persistence (immediate discontinuation and a medication possession ratio). We will conduct in-depth interviews with a purposive sample of 18 women, including 12 WESW and 6 peer navigators who support routine HIV screening and PrEP delivery, in two community hubs serving KPs since October 2021. We seek to value KP communities as equal contributors to the knowledge production process by actively engaging KP-CSOs throughout the research process. Expected outcomes include quantitative measures of PrEP initiation and persistence among WESW, and qualitative insights into the enablers and barriers to PrEP use informed by participants' lived experiences. ETHICS AND DISSEMINATION: WiSSPr was approved by the Institutional Review Boards of the University of Zambia (#3650-2023) and University of North Carolina (#22-3147). Participants must give written informed consent. Findings will be disseminated to the CAB, who will determine how to relay them to the community and stakeholders.

Low salinity stress increases the risk of Vibrio parahaemolyticus infection and gut microbiota dysbiosis in Pacific white shrimp.

BACKGROUND: Extreme precipitation events often cause sudden drops in salinity, leading to disease outbreaks in shrimp aquaculture. Evidence suggests that environmental stress increases animal host susceptibility to pathogens. However, the mechanisms of how low salinity stress induces disease susceptibility remain poorly understood. METHODS: We investigated the acute response of shrimp gut microbiota exposed to pathogens under low salinity stress. For comparison, shrimp were exposed to Vibrio infection under two salinity conditions: optimal salinity (Control group) and low salinity stress (Stress group). High throughput 16S rRNA sequencing and real-time PCR were employed to characterize the shrimp gut microbiota and quantify the severity level of Vibrio infection. RESULTS: The results showed that low salinity stress increased Vibrio infection levels, reduced gut microbiota species richness, and perturbed microbial functions in the shrimp gut, leading to significant changes in lipopolysaccharide biosynthesis that promoted the growth of pathogens. Gut microbiota of the bacterial genera Candidatus Bacilliplasma, Cellvibrio, and Photobacterium were identified as biomarkers of the Stress group. The functions of the gut microbiota in the Stress group were primarily associated with cellular processes and the metabolism of lipid-related compounds. CONCLUSIONS: Our findings reveal how environmental stress, particularly low salinity, increases shrimp susceptibility to Vibrio infection by affecting the gut microbiota. This highlights the importance of avoiding low salinity stress and promoting gut microbiota resilience to maintain the health of shrimp.

Poly(l-glutamic acid) augments the transfection performance of lipophilic polycations by overcoming tradeoffs among cytotoxicity, pDNA delivery efficiency, and serum stability.

Polycations are scalable and affordable nanocarriers for delivering therapeutic nucleic acids. Yet, cationicity-dependent tradeoffs between nucleic acid delivery efficiency, cytotoxicity, and serum stability hinder clinical translation. Typically, the most efficient polycationic vehicles also tend to be the most toxic. For lipophilic polycations-which recruit hydrophobic interactions in addition to electrostatic interactions to bind and deliver nucleic acids-extensive chemical or architectural modifications sometimes fail to resolve intractable toxicity-efficiency tradeoffs. Here, we employ a facile post-synthetic polyplex surface modification strategy wherein poly(l-glutamic acid) (PGA) rescues toxicity, inhibits hemolysis, and prevents serum inhibition of lipophilic polycation-mediated plasmid (pDNA) delivery. Importantly, the sequence in which polycations, pDNA, and PGA are combined dictates pDNA conformations and spatial distribution. Circular dichroism spectroscopy reveals that PGA must be added last to polyplexes assembled from lipophilic polycations and pDNA; else, PGA will disrupt polycation-mediated pDNA condensation. Although PGA did not mitigate toxicity caused by hydrophilic PEI-based polycations, PGA tripled the population of transfected viable cells for lipophilic polycations. Non-specific adsorption of serum proteins abrogated pDNA delivery mediated by lipophilic polycations; however, PGA-coated polyplexes proved more serum-tolerant than uncoated polyplexes. Despite lower cellular uptake than uncoated polyplexes, PGA-coated polyplexes were imported into nuclei at higher rates. PGA also silenced the hemolytic activity of lipophilic polycations. Our work provides fundamental insights into how polyanionic coatings such as PGA transform intermolecular interactions between lipophilic polycations, nucleic acids, and serum proteins, and facilitate gentle yet efficient transgene delivery.

Synergistic Polymer Blending Informs Efficient Terpolymer Design and Machine Learning Discerns Performance Trends for pDNA Delivery.

Cationic polymers offer an alternative to viral vectors in nucleic acid delivery. However, the development of polymer vehicles capable of high transfection efficiency and minimal toxicity has remained elusive, and continued exploration of the vast design space is required. Traditional single polymer syntheses with large monomer bases are very time-intensive, limiting the speed at which new formulations are identified. In this work, we present an experimental method for the quick probing of the design space, utilizing a combinatorial set of 90 polymer blends, derived from 6 statistical copolymers, to deliver pDNA. This workflow facilitated rapid screening of polyplex compositions, successfully tailoring polyplex hydrophobicity, particle size, and payload binding affinity. This workflow identified blended polyplexes with high levels of transfection efficiency and cell viability relative to single copolymer controls and commercial JetPEI, indicating synergistic benefits from copolymer blending. Polyplex composition was coupled with biological outputs to guide the synthesis of single terpolymer vehicles, with high-performing polymers P10 and M20, providing superior transfection of HEK293T cells in serum-free and serum-containing media, respectively. Machine learning coupled with SHapley Additive exPlanations (SHAP) was used to identify polymer/polyplex attributes that most impact transfection efficiency, viability, and overall effective efficiency. Subsequent transfections on ARPE-19 and HDFn cells found that P10 and M20 were surpassed in performance by M10, contrasting with results in HEK293T cells. This cell type dependency reinforced the need to evaluate transfection conditions with multiple cell models to potentially identify moieties more beneficial to delivery in certain tissues. Overall, the workflow employed can be used to expedite the exploration of the polymer design space, bypassing extensive synthesis, and to develop improved polymer delivery vehicles more readily for nucleic acid therapies.

Mortality among persons with tuberculosis in Zambian hospitals: A retrospective cohort study.

Tuberculosis (TB) mortality in Zambia remains high at 86 per 100,000 populations, translating to approximately 15,000 TB-related deaths annually. We conducted a nationwide retrospective cohort study to understand predictors, time to death, and probable causes of mortality among persons on TB treatment in Zambia. We reviewed medical records for persons with TB registered in 54 purposively selected hospitals in Zambia between January and December 2019. We fitted a Cox proportional hazards model to identify predictors of mortality. Of the 13,220 records abstracted, 10,987 were analyzed after excluding records of persons who transferred in from other hospitals, those with inconsistent dates and those whose treatment outcome was not evaluated. The majority of persons with TB were men, (61.5%, n = 6,761) with a median age of 36 years (IQR: 27-46 years). Overall, 1,063 (9.7%) died before completing TB treatment (incidence rate = 16.9 deaths per 1,000 person-months). Median age at death was 40 years (IQR: 31-52). The majority of deaths (75.7%, n = 799) occurred in the first two months of TB treatment, with a median time to death of 21 days (IQR: 6-57). Independent risk factors for TB mortality included age >54 years, being treated in Eastern, Southern, Western, Muchinga and Central provinces, receiving treatment from a third-level or mission hospital, methods of diagnosis other than Xpert MTB/RIF, extrapulmonary TB (EPTB), and positive HIV status. Probable causes of death were septic shock (18.8%), TB Immune Reconstitution Inflammatory Syndrome (TB IRIS) (17.8%), end-organ damage (13.4%), pulmonary TB (11.4%), anemia (9.6%) and TB meningitis (7.8%). These results show high mortality among people undergoing TB treatment in Zambia. Interventions targeted at persons most at risk such as the elderly, those with EPTB, and those living with HIV, can help reduce TB-related mortalities in Zambia.

"Current", "heated rods", and "hot vapour": why patients refuse radiotherapy as a treatment modality for cancer in northern Sri Lanka.

PURPOSE: Significant proportions of patients either refuse or discontinue radiotherapy, even in the curative setting, leading to poor clinical outcomes. This study explores patient perceptions that underlie decisions to refuse/discontinue radiotherapy at a cancer care facility in northern Sri Lanka. METHODS: An exploratory descriptive qualitative study was carried out among 14 purposively selected patients with cancer who refused/discontinued radiotherapy. In-depth semi-structured interviews were transcribed in Tamil, translated into English, coded, and thematically analyzed. RESULTS: All participants referred to radiotherapy as "current" with several understanding the procedure to involve electricity, heat, or hot vapour. Many pointed to gaps in information provided by healthcare providers, who were perceived to focus on side effects without explaining the procedure. In the absence of these crucial details, patients relied on family members and acquaintances for information, often based on second or third-hand accounts of experiences with radiotherapy. Many felt pressured by family to refuse radiation, feared radiation, or felt ashamed to ask questions, while for others COVID-19 was an impediment. All but three participants regretted their decision, claiming they would recommend radiation to patients with cancer, especially when it is offered with curative intent. CONCLUSION: Patients with cancer who refused/discontinued radiation therapy have significant information needs. While human resource deficits need to be addressed in low-resource settings like northern Sri Lanka, providing better supportive cancer care could improve clinical outcomes and save healthcare resources that would otherwise be wasted on patient preparation for radiotherapy.

Decolonising global health research: Shifting power for transformative change.

Recent debates on decolonizing global health have spurred interest in addressing the power asymmetries and knowledge hierarchies that sustain colonial ideas and relationships in global health research. This paper applies three intersecting dimensions of colonialism (colonialism within global health; colonisation of global health; and colonialism through global health) to develop a broader and more structural understanding of the policies and actions needed to decolonise global health research. It argues that existing guidelines and checklists designed to make global health research more equitable do not adequately address the underlying power asymmetries and biases that prevail across the global health research ecosystem. Beyond encouraging fairer partnerships within individual research projects, this paper calls for more emphasis on shifting the balance of decision-making power, redistributing resources, and holding research funders and other power-holders accountable to the places and peoples involved in and impacted by global health research.

Developing an agenda for the decolonization of global health.

Colonialism, which involves the systemic domination of lands, markets, peoples, assets, cultures or political institutions to exploit, misappropriate and extract wealth and resources, affects health in many ways. In recent years, interest has grown in the decolonization of global health with a focus on correcting power imbalances between high-income and low-income countries and on challenging ideas and values of some wealthy countries that shape the practice of global health. We argue that decolonization of global health must also address the relationship between global health actors and contemporary forms of colonialism, in particular the current forms of corporate and financialized colonialism that operate through globalized systems of wealth extraction and profiteering. We present a three-part agenda for action that can be taken to decolonize global health. The first part relates to the power asymmetries that exist between global health actors from high-income and historically privileged countries and their counterparts in low-income and marginalized settings. The second part concerns the colonization of the structures and systems of global health governance itself. The third part addresses how colonialism occurs through the global health system. Addressing all forms of colonialism calls for a political and economic anticolonialism as well as social decolonization aimed at ensuring greater national, racial, cultural and knowledge diversity within the structures of global health.

Le colonialisme, qui implique la domination systémique de terres, de marchés, de peuples, de ressources, de cultures ou d'institutions politiques dans le but d'exploiter, de détourner et d'extraire des richesses et des ressources, affecte la santé de nombreuses manières. Ces dernières années, la décolonisation de la santé mondiale a suscité un intérêt croissant, l'accent étant mis sur la correction des déséquilibres de pouvoir entre les pays à revenu élevé et les pays à faible revenu, ainsi que sur la remise en question des idées et des valeurs de certains pays riches qui façonnent la pratique de la santé mondiale. Nous soutenons que la décolonisation de la santé mondiale doit également aborder la relation entre les acteurs de la santé mondiale et les formes contemporaines de colonialisme, en particulier les formes actuelles de colonialisme d'entreprise et de colonialisme financiarisé qui opèrent par des systèmes mondialisés d'extraction de richesses et de profits. Nous présentons un programme d'action en trois parties destiné à décoloniser la santé mondiale. La première partie porte sur les asymétries de pouvoir existant entre les acteurs de la santé mondiale des pays à hauts revenus et historiquement privilégiés et leurs homologues des pays à faibles revenus et marginalisés. La deuxième partie concerne la colonisation des structures et des systèmes de la gouvernance mondiale de la santé elle-même. La troisième partie traite de la manière dont le colonialisme se manifeste à travers le système de santé mondial. La lutte contre toutes les formes de colonialisme nécessite un anticolonialisme politique et économique ainsi qu'une décolonisation sociale visant à garantir une plus grande diversité nationale, raciale, culturelle et des connaissances au sein des structures de la santé mondiale.

El colonialismo, que implica la dominación sistémica de tierras, mercados, pueblos, bienes, culturas o instituciones políticas para explotar, apropiarse indebidamente y extraer riqueza y recursos, afecta a la salud de muchas maneras. En los últimos años ha crecido el interés por descolonizar la salud mundial, en particular para corregir los desequilibrios de poder entre los países de ingresos altos y los de ingresos bajos, y para cuestionar las ideas y los valores de algunos países ricos que influyen en la práctica de la salud mundial. Sostenemos que la descolonización de la salud mundial también debe abordar la relación entre los actores de la salud mundial y las formas contemporáneas de colonialismo, en especial las formas actuales de colonialismo corporativo y financiarizado que operan a través de sistemas globalizados de extracción de riqueza y especulación. Presentamos un programa de acción dividido en tres partes para descolonizar la salud mundial. La primera parte se refiere a las asimetrías de poder que existen entre los actores de la salud mundial procedentes de países de ingresos altos e históricamente privilegiados y sus homólogos de entornos de ingresos bajos y marginados. La segunda parte se refiere a la colonización de las estructuras y sistemas de la propia gobernanza de la salud mundial. La tercera parte aborda cómo se produce el colonialismo a través del sistema sanitario mundial. Abordar todas las formas de colonialismo exige un anticolonialismo político y económico, así como una descolonización social destinada a garantizar una mayor diversidad nacional, racial, cultural y de conocimientos dentro de las estructuras de la salud mundial.

Shrimp SIRT4 promotes white spot syndrome virus replication.

In WSSV pathogenesis, the molecular mechanisms and the key host factors that regulate the viral replication and morphogenesis remain unclear. However, like most viruses, WSSV is known to induce metabolic reprogramming in several metabolic pathways including the host glutamine metabolism, and several recent reports have suggested that the sirtuins SIRT3, SIRT4, and SIRT5, which belong to a family of NAD+-dependent deacetylases, play an important role in this regulation. Here we focus on characterizing LvSIRT4 from Litopenaeus vannamei and investigate its role in regulating glutamine dehydrogenase (GDH), an important enzyme that promotes glutaminolysis and viral replication. We found that LvSIRT4 silencing led to significant decreases in both WSSV gene expression and the number of viral genome copies. Conversely, overexpression of LvSIRT4 led to significant increases in the expression of WSSV genes and the WSSV genome copy number. Immunostaining in Sf9 insect cells confirmed the presence of LvSIRT4 in the mitochondria and the co-localization of LvSIRT4 and LvGDH in the same cellular locations. In vivo gene silencing of LvSIRT4 significantly reduced the gene expression of LvGDH whereas LvSIRT4 overexpression had no effect. However, neither silencing nor overexpression had any effect on the protein expression levels of LvGDH. Lastly, although GDH activity in uninfected shrimp was unchanged, the GDH enzyme activity in WSSV-infected shrimp was significantly increased after both LvSIRT4 silencing and overexpression. This suggests that although there may be no direct regulation, LvSIRT4 might still be able to indirectly regulate LvGDH via the mediation of one or more WSSV proteins that have yet to be identified.

Machine Learning Elucidates Design Features of Plasmid DNA Lipid Nanoparticles for Cell Type-Preferential Transfection.

For cell and gene therapies to become more broadly accessible, it is critical to develop and optimize non-viral cell type-preferential gene carriers such as lipid nanoparticles (LNPs). Despite the effectiveness of high throughput screening (HTS) approaches in expediting LNP discovery, they are often costly, labor-intensive, and often do not provide actionable LNP design rules that focus screening efforts on the most relevant chemical and formulation parameters. Here we employed a machine learning (ML) workflow using well-curated plasmid DNA LNP transfection datasets across six cell types to maximize chemical insights from HTS studies and has achieved predictions with 5-9% error on average depending on cell type. By applying Shapley additive explanations to our ML models, we unveiled composition-function relationships dictating cell type-preferential LNP transfection efficiency. Notably, we identified consistent LNP composition parameters that enhance in vitro transfection efficiency across diverse cell types, such as ionizable to helper lipid ratios near 1:1 or 10:1 and the incorporation of cationic/zwitterionic helper lipids. In addition, several parameters were found to modulate cell type-preferentiality, including the ionizable and helper lipid total molar percentage, N/P ratio, cholesterol to PEGylated lipid ratio, and the chemical identity of the helper lipid. This study leverages HTS of compositionally diverse LNP libraries and ML analysis to understand the interactions between lipid components in LNP formulations; and offers fundamental insights that contribute to the establishment of unique sets of LNP compositions tailored for cell type-preferential transfection.

Gut microbiota of Pacific white shrimp (Litopenaeus vannamei) exhibits distinct responses to pathogenic and non-pathogenic Vibrio parahaemolyticus.

Acute hepatopancreatic necrosis disease (AHPND), a high-mortality-rate shrimp disease, is caused by specific Vibrio parahaemolyticus (Vp) strains with a plasmid encoding the PirABVp toxins. As a bacterial pathogen, the invasion of AHPND-causing Vp might impose pressure on commensal microbiota in the shrimp gut, while the relationship between the pathogenesis of AHPND and the dysbiosis of gut bacterial communities remains unclear. Here we explored the temporal changes of shrimp gut microbiota in response to AHPND-causing and non-AHPND-causing Vp strains, with the non-infected controls as a baseline of the shrimp gut microbiota. The diversity and composition of bacterial communities from 168 gut samples (covering three treatments at seven time points with eight individuals per set) were investigated using 16S rRNA gene metabarcoding with high-throughput sequencing. The results showed that (i) species diversity of gut bacterial communities declined in Vp-infected shrimp, independent of the strain pathogenicity; (ii) taxonomic compositions of gut bacterial communities were significantly different between shrimp infected by AHPND-causing and non-AHPND-causing Vp strains; (iii) short-term (within 6 hours) compositional shifts in the gut microbiota were found only in AHPND-causing Vp-infected shrimp; (iv) the gut microbiota of AHPND-causing Vp-infected shrimp was enriched with genera Photobacterium and Vibrio, with a decline in Candidatus Bacilliplasma; and (v) functional predictions suggested the loss of normal metabolism due to compositional shifts in the gut microbiota. Our work reveals distinct features of community dynamics in shrimp gut microbiota, associated with pathogenic versus non-pathogenic Vibrio infections, providing a new perspective of the pathogenesis of AHPND. IMPORTANCE Shrimp production is continually threatened by newly emerging diseases, such as AHPND, which is caused by specific Vp strains. Previous studies on the pathogenesis of AHPND have mainly focused on the histopathology and immune responses of the host. However, more attention needs to be paid to the gut microbiota, which acts as the first barrier to pathogen colonization. In this study, we revealed that shrimp gut microbiota responded differently to pathogenic and non-pathogenic Vp strains, with bacterial genera Photobacterium and Vibrio enriched in pathogenic Vp-infected shrimp, and Candidatus Bacilliplasma enriched in non-pathogenic Vp-infected shrimp. Moreover, functional predictions suggested that changes in taxonomic compositions would further affect normal metabolic functions, emphasizing the importance of sustaining an equilibrium in the gut microbiota. Several biomarkers associated with specific microbial taxa and functional pathways were identified in our data sets, which help predict the incidence of disease outcomes.

Systematic review of global hepatitis E outbreaks to inform response and coordination initiatives.

INTRODUCTION: Hepatitis E virus (HEV) is the most common cause of acute hepatitis. While symptoms are generally mild and resolve within weeks, some populations (e.g., pregnant women, immunocompromised adults) are at high-risk of severe HEV-related morbidity and mortality. There has not been a recent comprehensive review of contemporary HEV outbreaks, which limits the validity of current disease burden estimates. Therefore, we aimed to characterize global HEV outbreaks and describe data gaps to inform HEV outbreak prevention and response initiatives. METHODS: We performed a systematic review of peer-reviewed (PubMed, Embase) and gray literature (ProMED) to identify reports of outbreaks published between 2011 and 2022. We included (1) reports with ≥ 5 cases of HEV, and/or (2) reports with 1.5 times the baseline incidence of HEV in a specific population, and (3) all reports with suspected (e.g., clinical case definition) or confirmed (e.g., ELISA or PCR test) cases if they met criterium 1 and/or 2. We describe key outbreak epidemiological, prevention and response characteristics and major data gaps. RESULTS: We identified 907 records from PubMed, 468 from Embase, and 247 from ProMED. We screened 1,362 potentially relevant records after deduplication. Seventy-one reports were synthesized, representing 44 HEV outbreaks in 19 countries. The populations at risk, case fatalities, and outbreak durations were not reported in 66% of outbreak reports. No reports described using HEV vaccines. Reported intervention efforts included improving sanitation and hygiene, contact tracing/case surveillance, chlorinating boreholes, and advising residents to boil water. Commonly missing data elements included specific case definitions used, testing strategy and methods, seroprevalence, impacts of interventions, and outbreak response costs. Approximately 20% of HEV outbreaks we found were not published in the peer-reviewed literature. CONCLUSION: HEV represents a significant public health problem. Unfortunately, extensive data shortages and a lack of standardized reporting make it difficult to estimate the HEV disease burden accurately and to implement effective prevention and response activities. Our study has identified major gaps to guide future studies and outbreak reporting systems. Our results support the development of standardized reporting procedures/platforms for HEV outbreaks to ensure accurate and timely data distribution, including active and passive coordinated surveillance systems, particularly among high-risk populations.

Resilience and probiotic interventions to prevent and recover from shrimp gut dysbiosis.

To counter the recurrent outbreaks of bacterial (acute hepatopancreatic necrosis disease; AHPND) and viral (white spot disease; WSD) shrimp diseases, which still remain a threat to the global industry, shrimp gut microbiota research has been gaining more attention in recent years, and the use of probiotics in aquaculture has had promising results in improving shrimp gut health and immunity. In this review based on our studies on AHPND and WSD, we summarize our current understanding of the shrimp gastrointestinal tract and the role of the microbiota in disease, as well as effects of probiotics. We focus particularly on the concept of microbiota resilience, and consider strategies that can be used to restore shrimp gut health by probiotic intervention at a crucial time during gut microbiota dysbiosis. Based on the available scientific evidence, we argue that the use of probiotics potentially has an important role in controlling disease in shrimp aquaculture.

A bacterial binary toxin system that kills both insects and aquatic crustaceans: Photorhabdus insect-related toxins A and B.

Photorhabdus insect-related toxins A and B (PirA and PirB) were first recognized as insecticidal toxins from Photorhabdus luminescens. However, subsequent studies showed that their homologs from Vibrio parahaemolyticus also play critical roles in the pathogenesis of acute hepatopancreatic necrosis disease (AHPND) in shrimps. Based on the structural features of the PirA/PirB toxins, it was suggested that they might function in the same way as a Bacillus thuringiensis Cry pore-forming toxin. However, unlike Cry toxins, studies on the PirA/PirB toxins are still scarce, and their cytotoxic mechanism remains to be clarified. In this review, based on our studies of V. parahaemolyticus PirAvp/PirBvp, we summarize the current understanding of the gene locations, expression control, activation, and cytotoxic mechanism of this type of toxin. Given the important role these toxins play in aquatic disease and their potential use in pest control applications, we also suggest further topics for research. We hope the information presented here will be helpful for future PirA/PirB studies.

White spot syndrome virus (WSSV) modulates lipid metabolism in white shrimp.

In addition to the Warburg effect, which increases the availability of energy and biosynthetic building blocks in WSSV-infected shrimp, WSSV also induces both lipolysis at the viral genome replication stage (12 hpi) to provide material and energy for the virus replication, and lipogenesis at the viral late stage (24 hpi) to complete virus morphogenesis by supplying particular species of long-chain fatty acids (LCFAs). Here, we further show that WSSV causes a reduction in lipid droplets (LDs) in hemocytes at the viral genome replication stage, and an increase in LDs in the nuclei of WSSV-infected hemocytes at the viral late stage. In the hepatopancreas, lipolysis is triggered by WSSV infection, and this leads to fatty acids being released into the hemolymph. ß-oxidation inhibition experiment reveals that the fatty acids generated by WSSV-induced lipolysis can be diverted into ß-oxidation for energy production. At the viral late stage, WSSV infection leads to lipogenesis in both the stomach and hepatopancreas, suggesting that fatty acids are in high demand at this stage for virion morphogenesis. Our results demonstrate that WSSV modulates lipid metabolism specifically at different stages to facilitate its replication.

Multiple Nucleocapsid Structural Forms of Shrimp White Spot Syndrome Virus Suggests a Novel Viral Morphogenetic Pathway.

White spot syndrome virus (WSSV) is a very large dsDNA virus. The accepted shape of the WSSV virion has been as ellipsoidal, with a tail-like extension. However, due to the scarcity of reliable references, the pathogenesis and morphogenesis of WSSV are not well understood. Here, we used transmission electron microscopy (TEM) and cryogenic electron microscopy (Cryo-EM) to address some knowledge gaps. We concluded that mature WSSV virions with a stout oval-like shape do not have tail-like extensions. Furthermore, there were two distinct ends in WSSV nucleocapsids: a portal cap and a closed base. A C14 symmetric structure of the WSSV nucleocapsid was also proposed, according to our Cryo-EM map. Immunoelectron microscopy (IEM) revealed that VP664 proteins, the main components of the 14 assembly units, form a ring-like architecture. Moreover, WSSV nucleocapsids were also observed to undergo unique helical dissociation. Based on these new results, we propose a novel morphogenetic pathway of WSSV.

Losses along the tuberculosis sputum sample referral cascade for Mpongwe District, Zambia.

BACKGROUND: In resource limited-settings, timely tuberculosis (TB) diagnosis depends upon referral of sputum samples from non-diagnostic to diagnostic facilities for examination. The TB programme data for 2018 suggested losses in Mpongwe District's sputum referral cascade. AIM: This study aimed to identify the referral cascade stage where loss of sputum specimen occurred. SETTING: Primary health care facilities in Mpongwe District, Copperbelt Province, Zambia. METHODS: Data were retrospectively collected from one central laboratory and six referring health facilities between January and June 2019, using a paper-based tracking sheet. Descriptive statistics were generated in SPSS version 22. RESULTS: Of the 328 presumptive pulmonary TB patients found in presumptive TB registers at referring facilities, 311 (94.8%) submitted sputum samples and were referred to the diagnostic facilities. Of these, 290 (93.2%) were received at the laboratory, and 275 (94.8%) were examined. The remaining 15 (5.2%) were rejected for reasons such as 'insufficient sample'. Results for all examined samples were sent back and received at referring facilities. Referral cascade completion rate was 88.4%. Median turnaround time was six days (IQR = 1.8). CONCLUSION: Losses in the sputum referral cascade for Mpongwe District mainly occurred between dispatch of sputum samples and receipt at diagnostic facility. Mpongwe District Health Office needs to establish a system to monitor and evaluate the movement of sputum samples along the referral cascade to minimize losses and ensure timely TB diagnosis.Contribution: This study has highlighted, at primary health care level for resource limited settings, the stage in the sputum sample referral cascade where losses mainly occur.