Factors Associated with Reliable Contact Tracing During the 2021 Ebola Virus Disease Outbreak in Guinea.

BACKGROUND: In 2021, an Ebola virus disease (EVD) outbreak was declared in Guinea, linked to persistent virus from the 2014-2016 West Africa Epidemic. This paper analyzes factors associated with contact tracing reliability (defined as completion of a 21-day daily follow-up) during the 2021 outbreak, and transitively, provides recommendations for enhancing contact tracing reliability in future. METHODS: We conducted a descriptive and analytical cross-sectional study using multivariate regression analysis of contact tracing data from 1071 EVD contacts of 23 EVD cases (16 confirmed and 7 probable). RESULTS: Findings revealed statistically significant factors affecting contact tracing reliability. Unmarried contacts were 12.76× more likely to miss follow-up than those married (OR = 12.76; 95% CI [3.39-48.05]; p < 0.001). Rural-dwelling contacts had 99% lower odds of being missed during the 21-day follow-up, compared to those living in urban areas (OR = 0.01; 95% CI [0.00-0.02]; p < 0.01). Contacts who did not receive food donations were 3× more likely to be missed (OR = 3.09; 95% CI [1.68-5.65]; p < 0.001) compared to those who received them. Contacts in health areas with a single team were 8× more likely to be missed (OR = 8.16; 95% CI [5.57-11.96]; p < 0.01) than those in health areas with two or more teams (OR = 1.00; 95% CI [1.68-5.65]; p < 0.001). Unvaccinated contacts were 30.1× more likely to be missed compared to vaccinated contacts (OR = 30.1; 95% CI [5.12-176.83]; p < 0.001). CONCLUSION: Findings suggest that contact tracing reliability can be significantly influenced by various demographic and organizational factors. Considering and understanding these factors-and where possible addressing them-may be crucial when designing and implementing contact tracing strategies during future outbreaks in low-resource settings.

PASQUALE - A long-term partnership to improve hand hygiene and capacity building in infection prevention and control in the Faranah region of Guinea.

Across the globe, hand hygiene (HH) is promoted to fight the spread of healthcare associated infections. Despite multiple ongoing HH campaigns and projects, the healthcare associated infection rates remain high especially in low- and middle-income countries. In the narrative overview presented here, we aim to share objectives, framework, successes and challenges of our long-term partnership in Guinea to offer guidance for other projects aiming to sustainably improve HH.

Neglected tropical diseases in Republic of Guinea: disease endemicity, case burden and the road towards the 2030 target.

Neglected tropical diseases (NTDs) predominantly affect vulnerable and marginalized populations in tropical and subtropical areas and globally affect more than one billion people. In Guinea, the burden of NTDs is estimated to be >7.5 disability-adjusted life years per million inhabitants. Currently the Guinea NTDs master plan (2017-2020) has identified eight diseases as public health problems: onchocerciasis, lymphatic filariasis, trachoma, schistosomiasis and soil-transmitted helminthiasis, leprosy, human African trypanosomiasis and Buruli ulcer. In this review we discuss the past and the current case burden of the priority NTDs in Guinea, highlight the major milestones and discuss current and future areas of focus for achieving the 2030 target outlined by the World Health Organization.

Investing in preparedness for rapid detection and control of epidemics: analysis of health system reforms and their effect on 2021 Ebola virus disease epidemic response in Guinea.

The 2014-2016 West Africa Ebola Virus Disease (EVD) Epidemic devastated Guinea's health system and constituted a public health emergency of international concern. Following the crisis, Guinea invested in the establishment of basic health system reforms and crucial legal instruments for strengthening national health security in line with the WHO's recommendations for ensuring better preparedness for (and, therefore, a response to) health emergencies. The investments included the scaling up of Integrated Disease Surveillance and Response; Joint External Evaluation of International Health Regulation capacities; National Action Plan for Health Security; Simulation Exercises; One Health platforms; creation of decentralised structures such as regional and prefectural Emergency Operation Centres; Risk assessment and hazard identification; Expanding human resources capacity; Early Warning Alert System and community preparedness. These investments were tested in the subsequent 2021 EVD outbreak and other epidemics. In this case, there was a timely declaration and response to the 2021 EVD epidemic, a lower-case burden and mortality rate, a shorter duration of the epidemic and a significant reduction in the cost of the response. Similarly, there was timely detection, response and containment of other epidemics including Lassa fever and Marburg virus disease. Findings suggest the utility of the preparedness activities for the early detection and efficient containment of outbreaks, which, therefore, underlines the need for all countries at risk of infectious disease epidemics to invest in similar reforms. Doing so promises to be not only cost-effective but also lifesaving.

Variations in the use of malaria preventive measures among pregnant women in Guinea: a secondary analysis of the 2012 and 2018 demographic and health surveys.

BACKGROUND: Despite its effectiveness, the optimal use of the combination of insecticide-treated nets (ITN) and intermittent preventive treatment during pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) remains low in malaria-endemic areas. Therefore, this study analyzed its variations and predictors in Guinea. METHODS: This study was a secondary analysis of the 2012 and 2018 Guinea Demographic and Health Surveys (DHS). It included women who had given birth 3 years before each DHS, slept on ITN and took at least one dose of SP. Use was complete if a pregnant woman slept on ITNs and took SP (at least two doses in 2012; at least three doses in 2018). Moran indices were used to determine spatial autocorrelation and classification methods to identify malaria preventive measures (MPM) predictors. RESULTS: In 2012, 60.88% of pregnant women had incomplete use of MPMs compared with 79.11% in 2018. Associated factors with incomplete MPMs in 2012 were as follows: having an indirect link with the head of household (AOR = 2.23, 95% CI 1.08-4.61) and performing at least 4 ANC visits (AOR = 0.66, 95% CI 0.44-0.99). In 2018: Living in households of 2 to 5 people (AOR = 0.54, 95% CI 0.36-0.80), have a man as the head of the household (AOR = 0.56, 95% CI 0.35-0.89), perform the first ANC in the second trimester of pregnancy (AOR = 0.74, 95% CI 0.54-0.99), perform at least 4 ANC visits (AOR = 0.47, 95% CI 0.36-0.62), have a job (AOR = 0. 67, 95% CI 0.50-0.88), give birth in a public health facility (AOR = 0.53, 95% CI 0.39-0.72) and the middle wealth quintile (AOR = 1.56, 95% CI 1.07-2.26). Analyses revealed a global autocorrelation (Moran index = 0.0009, p = 0.2349) and high-high clusters in Mamou in 2012. In 2018, autocorrelation was found (I Moran = 0.0169, p ≤ 0.05), with spatial clusters in 4 regions. CONCLUSION: The link with the head of household and the number of ANC visits were the main factors in MPMs. It is essential to implement strategies at the household level and health system level and monitor them to reduce inequality across regions.

Case Report: COVID-19 and Lassa Fever Coinfection in an Ebola Suspected Patient in Guinea.

In this case report, we describe a clinical presentation and therapeutic history of a unique case diagnosed with Lassa fever and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a 23-year-old man from Yomou prefecture in southeast Guinea identified with suspected Ebola Virus Disease (EVD) in the midst of an ongoing outbreak of that disease in the same region. On May 3, 2021, he was admitted to the Nzérékoré Epidemic disease treatment center where his clinical condition deteriorated significantly. Laboratory testing performed on the same day reveals a negative EVD polymerase chain reaction (PCR). Three days later, the patient was tested positive for SARS-CoV-2 and Lassa fever by reverse transcriptase PCR (RT-PCR) assays. Laboratory examination also indicated severe hematological and biochemical deteriorations in the patient. This case substantiates the need for systematic differential diagnosis during epidemic-prone disease outbreaks to better manage severely unwell patients.

Management of febrile illness in rural Guinea over a seven-year period: A retrospective study.

INTRODUCTION: Febrile illnesses constitute a major clinical challenge in tropical settings. We aimed to assess the frequency, presentation and management of febrile illness at two health facilities in Forécariah, Guinea, with a focus on appropriateness of antibiotic prescription. MATERIALS AND METHODS: This was a retrospective study conducted in patient files in a health center and a district hospital. Proportions of antibiotic prescription were determined by age group and syndromes as well as appropriateness of antibiotic prescription using the WHO model list (2019). RESULTS: From 2014 to 2020, 23,583 of 62,185 (38.0%) visits were related to febrile illness. Most patients with fever were female (56.1%) and evaluated at the health center (81.0%). Gastrointestinal (40.6%) and respiratory syndromes (36.8%), and undifferentiated fever (30.0%) were the most common presentations. Malaria was confirmed in 61.3% of the cohort. Overall, the rate of antibiotic prescription was high (14,834/23,583, 62.9%), mostly among patients aged <5 years (5,285/7,566, 69.9%), those with respiratory (7,577/8,684, 87.3%) and gastrointestinal (6,324/9,585, 66.0%) syndromes. Moreover, 7,432/14,465 (51.4%) patients with malaria were also prescribed an antibiotic. Penicillin (42.0%), cotrimoxazole (26.3%) and quinolones (18.7%) were the most frequently prescribed antibiotics. Overall, appropriateness of antibiotic prescription was low (38.3%), and even more so in patients with respiratory (29.1%) and gastrointestinal (25.8%) syndromes. CONCLUSIONS: Febrile illness is a major cause of consultation in rural Guinea. Rate of antibiotic prescription was high, even in confirmed malaria and was often considered inappropriate. There is a pressing need to investigate the etiological spectrum and improve the diagnostic approach of febrile illness in Guinea.

Neonatal and postneonatal tetanus at a referral hospital in Kamsar, Guinea: a retrospective audit of paediatric records (2014-2018).

BACKGROUND: Tetanus is a vaccine-preventable disease caused by the bacterium Clostridium tetani. In 2018, all of Guinea was considered to be at risk of the disease and the country is currently in the elimination phase. METHODS: A 5-y audit (1 January 2014-31 December 2018) of all admissions to the neonatal and general paediatric units of Kamsar Hospital (Western Guinea) was undertaken to identify cases of neonatal tetanus (NNT) and postneonatal tetanus (PNNT). RESULTS: There were 5670 admissions during the study period, of which 39 (0.7%) were due to tetanus (22 NNT and 17 PNNT). Among NNT patients, the bacterial entry site was the umbilical cord (n=20) or wound following circumcision (n=2). For PNNT, the entry site was surface wound (n=12), limb fracture (n=1) or could not be established (n=4). A majority of the patients (36/39, 92.3%) were born to unvaccinated mothers or those who received suboptimal vaccination during pregnancy. Overall, 21 (53.8%) children died within 7 d of admission with a higher mortality observed among neonates (16/22, 72.7%) compared with postneonates (5/17, 29.4%). CONCLUSIONS: Tetanus was a rare cause of admission at Kamsar Hospital with a very high case fatality rate. The disease primarily occurred among children born to mothers who were unvaccinated/inadequately vaccinated during pregnancy.

Malaria epidemiology and anti-malarial drug efficacy in Guinea: a review of clinical and molecular studies.

Malaria is one of the leading causes of mortality and morbidity in Guinea. The entire country is considered at risk of the disease. Transmission occurs all year round with peaks occurring from July through October with Plasmodium falciparum as the primary parasite species. Chloroquine (CQ) was the first-line drug against uncomplicated P. falciparum in Guinea until 2005, prior to the adoption of artemisinin-based combination therapy (ACT). In this review, data on therapeutic efficacy of CQ and artemisinin-based combinations reported in published literature is summarized. Against CQ, a failure rate of 27% (12/44) was reported in a study in 1992; a median failure rate of 15.6% [range: 7.7-28.3; 8 studies] was observed during 1996-2001, and 81% (17/21) of the patients failed to clear parasitaemia in a study conducted in 2007. For artemisinin-based combinations, three published studies were identified (1495 patients; 2004-2016); all three studies demonstrated day 28 polymerase chain reaction corrected efficacy > 95%. One study characterized kelch-13 mutations (389 tested; samples collected in 2016) with no evidence of mutations currently known to be associated with artemisinin resistance. The impact of the ongoing COVID-19 pandemic and widespread usage of counterfeit medicines are immediate challenges to malaria control activities in Guinea.

[Epidemiological and clinical profile of children with Coronavirus disease (COVID-19) at the Center for the Treatment of Epidemics and Infection Prevention (CTEIP) of the University Hospital of Donka in Conakry]. / Profil épidémiologique et clinique des enfants atteints de la maladie à coronavirus (COVID-19) au Centre de Traitement des Epidémies et Prévention des Infections (CTEPI) du CHU de Donka à Conakry.

COVID-19 is caused by SARS-CoV-2 virus, which is genetically similar to severe acute respiratory syndrome (SARS) virus. In pediatrics, it has a benign clinical course. Since the outbreak of COVID-19 pandemic in Guinea, whose epicenter was Conakry, pediatric cases have been reported at the CTEIP in Donka. The purpose of this study was to determine their epidemiological profile. We conducted a descriptive cross-sectional study of children aged 0-16 years admitted to the CTEIP, Donka, over a period of four months. Out of 7308 patients, coming predominantly from 5 communes of Conakry and hospitalized in the CTEPI, 189 were aged between 0 and 16 years (2 .59%). The majority of patients were within the age-group 0-4-years (38.62%) with a sex-ratio (F/M) of 1.52; 62.96% were students, 70% of children lived in Conakry, 28.57% of mothers were traders and contact persons (39.68%); 37.57% of fathers were civil servants, 2.65% of children had a history of sickle cell disease and 1.59% had allergic rhinitis. Asymptomatic patients accounted for 52.38% of cases and diagnosed patients were 74.6%. Symptoms included fever, rhinorrhea, headache, cough, abdominal pain, sneezing, diarrhea, physical asthenia. The incidence of COVID-19 among children hospitalized in the CTEIP of Donka is low. Children aged 5 years and older are more affected and nearly 50% are asymptomatic. Common symptoms are fever, headache, rhinorrhea, cough, abdominal pain, sneezing, diarrhea, physical asthenia.

Modifiable predictors of severe heart failure in Morocco: a descriptive study using routinely collected health data.

INTRODUCTION: Heart Failure (HF) is a growing public health concern in Morocco and there is a striking paucity on determinants of severe HF (SHF) in this population. The aim of this study was to identify patients admitted with HF at Ibn Rochd Hospital, Casablanca from 2011 onwards, when electronic record keeping began. METHODS: A total of 105 patients underwent a series of cardiological examinations between July 2011 and January 2014. The New York Heart Association (NYHA) criteria was used to evaluate the severity of HF. Patients with NYHA classification gradings of I and II were defined as having moderate HF (MHF) and those graded as III and IV were defined as having a SHF. Univariable and multivariable risk factors associated with SHF were explored using logistic regression. The results were reported following the RECORD (Reporting of studies Conducted using Observational Routinely-collected Data) statement. RESULTS: A total of 24 (33%) patients were identified as having a SHF. Four predictors of SHF were identified in univariate analysis: haemoglobin <12g/dL, neutrophil-to-lymphocyte ratio (NLR) >3, mean corpuscular haemoglobin concentration (MCHC) <32 picolitre, and high density lipoprotein (HDL) <0.35 (mmol/L). Only NLR>3 and HDL <0.35 mmol/L remained independent predictors in multivariable analysis. Patients with NLR >3 were at 6-fold increased odds of SHF [adjusted odds ratio (AOR): 6.78, 95% confidence interval (CI): 1.40-32.80, p=0.017], and those with HDL<0.35 (mmol/L) were at 10-fold increased odds of SHF [AOR: 10.11, 95% CI: 2.26-45.27, p=0.002]. CONCLUSION: The independent biomarkers of SHF identified in this study provide valuable information to ward clinicians in resource-constrained facilities to identify patients vulnerable to developing severe heart complications.

Morbidity and mortality outcomes in neonates who were transferred from home and hospitals to the only neonatal intensive care unit in Guinea: a descriptive report using routinely collected health data.

BACKGROUND: The Sustainable Development Goal (SDG) for neonatal mortality has identified its reduction as one of the main targets to be achieved by 2030. We provide a descriptive report on neonatal outcomes from the only neonatal intensive care unit (NICU) in Guinea. METHODS: Data collection took place between November 2004 and May 2005 at the NICU of the Institute of Child Health in the capital, Conakry. A descriptive summary of the neonatal, maternal and intrapartum characteristics is reported. RESULTS: A total of 294 neonates were admitted to the NICU incubators during the study period, transferred either from hospitals (48%) or directly from their homes (52%). The most common reasons for admission were foetal distress (37.1%) and maternal-foetal infections (35.4%). Among 270 neonates with known outcome, the overall mortality among the admitted children remained high at 20.7% (56/270),with a large proportion of the deaths (71.4%, 40/56) occurring within 7 d of their admission. The mortality rate was 23.7% (31/131) among the neonates who were admitted to our NICU after home birth and 17.9% (25/139) among those who were transferred from hospitals (OR: 1.41, 95% CI: 0.75-2.67). CONCLUSION: Almost one in every five neonates who were admitted to the NICU incubator died during the study period. More hospitals equipped with NICU facilities are urgently required if Guinea is to achieve the SDG target for neonatal mortality.

Elevated IL-17 levels in semi-immune anaemic mice infected with Plasmodium berghei ANKA.

BACKGROUND: Alterations in inflammatory cytokines and genetic background of the host contribute to the outcome of malaria infection. Despite the promising protective role of IL-17 in infections, little attention is given to further understand its importance in the pathogenesis of severe malaria anaemia in chronic/endemic situations. The objective of this study, therefore, was to evaluate IL-17 levels in anaemic condition and its association with host genetic factors. METHODS: Two mice strains (Balb/c and CBA) were crossed to get the F1 progeny, and were (F1, Balb/c, CBA) taken through 6 cycles of Plasmodium berghei (ANKA strain) infection and chloroquine/pyrimethamine treatment to generate semi-immune status. Cytokine levels and kinetics of antibody production, CD4+CD25+T regulatory cells were evaluated by bead-based multiplex assay kit, ELISA and FACs, respectively. RESULTS: High survival with high Hb loss at significantly low parasitaemia was observed in Balb/c and F1. Furthermore, IgG levels were two times higher in Balb/c, F1 than CBA. While CD4+CD25+ Treg cells were lower in CBA; IL-4, IFN-γ, IL-12α and IL-17 were significantly higher (p < 0.05) in Balb/c, F1. CONCLUSIONS: In conclusion, elevated IL-17 levels together with high IL-4, IL-12α and IFN-γ levels may be a marker of protection, and the mechanism may be controlled by host factor (s). Further studies of F2 between the F1 and Balb/c will be informative in evaluating if these genes are segregated or further apart.

Prognostic and Predictive Factors of Ebola Virus Disease Outcome in Elderly People during the 2014 Outbreak in Guinea.

Elderly people occupy a prominent position in African societies; however, their potential linkage to high case fatality rate (CFR) in Ebola virus disease (EVD) was often overlooked. We describe the predictive factors for EVD lethality in the elderly. A total of 2,004 adults and 309 elderly patients with confirmed EVD were included in the analysis. The median age (interquartile range) was 35 years (23-44) in adults and 65 years (60-70) in the elderly. The proportion of funeral participation was significantly higher in the elderly group than in the adult group. Duration (in days) between the onset of symptoms and admission was significantly longer in elderly. CFR in the elderly people was also significantly higher (80.6%) than in the adult group (66.2%). Funeral participation constituted a risk factor for the transmission of EVD in elderly people.

Dengue Virus Serotypes 1 and 2 Responsible for Major Dengue Outbreaks in Nepal: Clinical, Laboratory, and Epidemiological Features.

Dengue virus (DENV) is expanding toward previously nonendemic areas. DENV has recently been introduced in Nepal with limited information. We report the clinical features and serotype distribution of DENV in Nepal during the 2010 outbreaks. A total of 1,215 clinical dengue cases at two major hospitals of central and western Nepal were investigated. Demographic, clinical, and laboratory parameters were recorded. Serum specimens were tested for DENV by IgM/IgG enzyme-linked immunosorbent assays (ELISAs) and reverse transcription polymerase chain reaction (RT-PCR). We confirmed DENV infection in 403 (33%) patients from 12 districts with an estimated case fatality rate of 1.5%. DENV infection was more common in adults (87%) and urban settings (74%). We detected all four serotypes but DENV-1 and -2 were mainly responsible for major outbreaks (92%). Overall, 60% of all DENV infections were secondary and 17% were severe dengue; both being more frequent among the DENV-2 infections. Rash, bleeding, abdominal pain, hepatomegaly, elevated liver enzymes, and thrombocytopenia were significantly more common in severe dengue compared with nonsevere infections. We also confirmed the expansion of dengue to hill urban areas (DENV-1 and -2), including the capital Kathmandu (altitude, 1,300 m) though > 90% cases were from southern plains. Differential clinical and laboratory features probably help in clinical decisions. Multiple serotypes circulation and elevated secondary infections pose potential risk of severe outbreaks and deaths in the future. Therefore, a country with recent dengue introduction, like Nepal, urgently requires a systematic surveillance and appropriate control measures in place to respond to any disastrous outbreaks.

Ebola virus disease in children during the 2014-2015 epidemic in Guinea: a nationwide cohort study.

The most recent epidemic of Ebola virus disease (EVD) has resulted in more than 11,000 deaths in West Africa. It has threatened child health in the affected countries, including Guinea. This nationwide retrospective cohort study included all children under 20 years of age with laboratory-confirmed EVD in Guinea during the 2014-2015 Ebola outbreak for analysis. Of 8,448 children with probable or suspected EVD, 695 cases were laboratory-confirmed EVD. The overall case fatality rate (CFR) was 62.9%. Pediatric patients with younger age had a significantly higher rate of death (adjusted OR = 0.995; 95%CI = 0.990-1.000; p = 0.046), with the highest CFR of 82.9% in children aged less than 5 years. Fever (91%), fatigue (87%), and gastrointestinal signs and symptoms (70%) were common clinical features on admission of the pediatric patients, while bleeding signs were not occurring often (24%). None of clinical features and epidemiologic risk factors for Ebola were associated with mortality outcome in our cohort study. CONCLUSION: EVD is a major threat to child health, especially among children under 5 years of age. To date, none of demographic and clinical features, except younger age, have been consistently shown to affect mortality outcome in children infected with Ebola virus. What is Known: • The 2014-2015 West Africa Ebola epidemic is the largest and most widespread outbreak of Ebola virus disease (EVD) in history, with more than 11,000 deaths in Guinea, Liberia, and Sierra Leone. • During ongoing outbreak investigations, it is suggested that young children aged less than 5 years are particularly vulnerable and highly susceptible to death. What is New: • Demographic and clinical characteristics of the nationwide cohort of pediatric patients with laboratory-confirmed EVD in Guinea are reported. • The results confirm the high rate of death among EVD children under 5 years of age, while none of demographic and clinical features, except younger age, could serve as a predictor of mortality outcome in pediatric patients with EVD.

Deployment of a Reverse Transcription Loop-Mediated Isothermal Amplification Test for Ebola Virus Surveillance in Remote Areas in Guinea.

To strengthen the laboratory diagnostic capacity for Ebola virus disease (EVD) in the remote areas of Guinea, we deployed a mobile field laboratory and implemented reverse transcription loop-mediated isothermal amplification (RT-LAMP) for postmortem testing. We tested 896 oral swab specimens and 21 serum samples, using both RT-LAMP and reverse transcription-polymerase chain reaction (RT-PCR). Neither test yielded a positive result, and the results from RT-LAMP and RT-PCR were consistent. More than 95% of the samples were tested within 2 days of sample collection. These results highlight the usefulness of the RT-LAMP assay as an EVD diagnostic testing method in the field or remote areas.

Immunogenicity and anti-fecundity effect of nanoparticle coated glutathione S-transferase (SjGST) DNA vaccine against murine Schistosoma japonicum infection.

There is still urgent need for a vaccine against schistosomiasis, especially in Schistosoma japonicum endemic areas where even a vaccine that will interrupt zoonotic transmission will be potentially effective as an intervention tool. We had developed a novel nanoparticle gene delivery system, which has proven efficacious in gene transfection to target immune cells with complementary adjuvant effect and high protective efficacy in several diseases. Here, we applied this nanoparticle system in combination with S. japonicum glutathione S-transferase (SjGST) DNA vaccine to show the immunogenicity and anti-fecundity effect of the nanoparticle coated vaccine formulation against murine schistosomiasis. The nanoparticle-coated DNA vaccine formulation induced desired immune responses. In comparison with the nanoparticle coated empty vector, it produced significantly increased antigen-specific humoral response, T-helper 1 polarized cytokine environment, higher proportion of IFN-γ producing CD4(+) T-cells and the concomitant decrease in IL-4 producing CD4(+) T-cells. Although there was no effect on worm burden, we recorded a marked reduction in tissue egg burden. There was up to 71.3% decrease in tissue egg burden and 55% reduction in the fecundity of female adult worms. Our data showed that SjGST DNA vaccine, delivered using the nanoparticle gene delivery system, produced anti-fecundity effect on female adult schistosomes as previously described by using conventional subunit vaccine with adjuvant, proving this DNA vaccine formulation as a promising candidate for anti-pathology and transmission blocking application.

Nanoparticle formulation enhanced protective immunity provoked by PYGPI8p-transamidase related protein (PyTAM) DNA vaccine in Plasmodium yoelii malaria model.

We have previously reported the new formulation of polyethylimine (PEI) with gamma polyglutamic acid (γ-PGA) nanoparticle (NP) to have provided Plasmodium yoelii merozoite surface protein-1 (PyMSP-1) plasmid DNA vaccine with enhanced protective cellular and humoral immunity in the lethal mouse malaria model. PyGPI8p-transamidase-related protein (PyTAM) was selected as a possible candidate vaccine antigen by using DNA vaccination screening from 29 GPI anchor and signal sequence motif positive genes picked up using web-based bioinformatics tools; though the observed protection was not complete. Here, we observed augmented protective effect of PyTAM DNA vaccine by using PEI and γ-PGA complex as delivery system. NP-coated PyTAM plasmid DNA immunized mice showed a significant survival rate from lethal P. yoelii challenge infection compared with naked PyTAM plasmid or with NP-coated empty plasmid DNA group. Antigen-specific IgG1 and IgG2b subclass antibody levels, proportion of CD4 and CD8T cells producing IFN-γ in the splenocytes and IL-4, IFN-γ, IL-12 and TNF-α levels in the sera and in the supernatants from ex vivo splenocytes culture were all enhanced by the NP-coated PyTAM DNA vaccine. These data indicates that NP augments PyTAM protective immune response, and this enhancement was associated with increased DC activation and concomitant IL-12 production.

Characterization of a gene family encoding SEA (sea-urchin sperm protein, enterokinase and agrin)-domain proteins with lectin-like and heme-binding properties from Schistosoma japonicum.

BACKGROUND: We previously identified a novel gene family dispersed in the genome of Schistosoma japonicum by retrotransposon-mediated gene duplication mechanism. Although many transcripts were identified, no homolog was readily identifiable from sequence information. METHODOLOGY/PRINCIPAL FINDINGS: Here, we utilized structural homology modeling and biochemical methods to identify remote homologs, and characterized the gene products as SEA (sea-urchin sperm protein, enterokinase and agrin)-domain containing proteins. A common extracellular domain in this family was structurally similar to SEA-domain. SEA-domain is primarily a structural domain, known to assist or regulate binding to glycans. Recombinant proteins from three members of this gene family specifically interacted with glycosaminoglycans with high affinity, with potential implication in ligand acquisition and immune evasion. Similar approach was used to identify a heme-binding site on the SEA-domain. The heme-binding mode showed heme molecule inserted into a hydrophobic pocket, with heme iron putatively coordinated to two histidine axial ligands. Heme-binding properties were confirmed using biochemical assays and UV-visible absorption spectroscopy, which showed high affinity heme-binding (K D = 1.605×10(-6) M) and cognate spectroscopic attributes of hexa-coordinated heme iron. The native proteins were oligomers, antigenic, and are localized on adult worm teguments and gastrodermis; major host-parasite interfaces and site for heme detoxification and acquisition. CONCLUSIONS: The results suggest potential role, at least in the nucleation step of heme crystallization (hemozoin formation), and as receptors for heme uptake. Survival strategies exploited by parasites, including heme homeostasis mechanism in hemoparasites, are paramount for successful parasitism. Thus, assessing prospects for application in disease intervention is warranted.