scholarly journals Optimization of Plasmodium vivax sporozoite production from Anopheles stephensi in South West India

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Ajeet Kumar Mohanty ◽  
Charles de Souza ◽  
Deepika Harjai ◽  
Prathamesh Ghavanalkar ◽  
Mezia Fernandes ◽  
...  
Keyword(s):  
South Asia ◽  
Plasmodium Vivax ◽  
Anopheles Stephensi ◽  
Parasite Development ◽  
Future Research ◽  
High Quality ◽  
Gametocyte Density ◽  
Feeding Experiments ◽  
South West ◽  
Membrane Feeding

Abstract Background Efforts to study the biology of Plasmodium vivax liver stages, particularly the latent hypnozoites, have been hampered by the limited availability of P. vivax sporozoites. Anopheles stephensi is a major urban malaria vector in Goa and elsewhere in South Asia. Using P. vivax patient blood samples, a series of standard membrane-feeding experiments were performed with An. stephensi under the US NIH International Center of Excellence for Malaria Research (ICEMR) for Malaria Evolution in South Asia (MESA). The goal was to understand the dynamics of parasite development in mosquitoes as well as the production of P. vivax sporozoites. To obtain a robust supply of P. vivax sporozoites, mosquito-rearing and mosquito membrane-feeding techniques were optimized, which are described here. Methods Membrane-feeding experiments were conducted using both wild and laboratory-colonized An. stephensi mosquitoes and patient-derived P. vivax collected at the Goa Medical College and Hospital. Parasite development to midgut oocysts and salivary gland sporozoites was assessed on days 7 and 14 post-feeding, respectively. The optimal conditions for mosquito rearing and feeding were evaluated to produce high-quality mosquitoes and to yield a high sporozoite rate, respectively. Results Laboratory-colonized mosquitoes could be starved for a shorter time before successful blood feeding compared with wild-caught mosquitoes. Optimizing the mosquito-rearing methods significantly increased mosquito survival. For mosquito feeding, replacing patient plasma with naïve serum increased sporozoite production > two-fold. With these changes, the sporozoite infection rate was high (> 85%) and resulted in an average of ~ 22,000 sporozoites per mosquito. Some mosquitoes reached up to 73,000 sporozoites. Sporozoite production could not be predicted from gametocyte density but could be predicted by measuring oocyst infection and oocyst load. Conclusions Optimized conditions for the production of high-quality P. vivax sporozoite-infected An. stephensi were established at a field site in South West India. This report describes techniques for producing a ready resource of P. vivax sporozoites. The improved protocols can help in future research on the biology of P. vivax liver stages, including hypnozoites, in India, as well as the development of anti-relapse interventions for vivax malaria.

scholarly journals Transmission blocking immunity in Plasmodium vivax malaria: antibodies raised against a peptide block parasite development in the mosquito vector.

1995 ◽  
Vol 181 (1) ◽  
pp. 357-362 ◽  
Author(s):  
V A Snewin ◽  
S Premawansa ◽  
G M Kapilananda ◽  
L Ratnayaka ◽  
P V Udagama ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Parasite Development ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mosquito Vector ◽  
Conformational Structure ◽  
Expression Library ◽  
Western Blots ◽  
Transmission Blocking ◽  
Genomic Expression ◽  
Membrane Feeding

One approach towards the development of a vaccine against malaria is to immunize against the parasite sexual stages that mediate transmission of the parasite from man to mosquito. Antibodies against these stages, ingested with the blood meal, inhibit the parasite development in the mosquito vector, constituting "transmission blocking immunity." Most epitopes involved in transmission-blocking immunity depend on the tertiary conformational structure of surface antigens. However, one of the transmission-blocking monoclonal antibodies we have raised against Plasmodium vivax reacts with a linear epitope on both asexual stages and gametes. This monoclonal antibody (A12) is capable of totally blocking development of the parasite in the mosquito host when tested in membrane feeding assays with gametocytes from P. vivax-infected patients. Immune screening of a P. vivax lambda gt11 genomic expression library with A12 led to the isolation of a clone to which was mapped the six-amino acid epitope recognized by A12. Antisera raised in mice against a 12-mer synthetic peptide containing this epitope coupled to bovine serum albumin not only had high titers of antipeptide antibodies as measured by enzyme-linked immunosorbent assay, but in addition recognized the same 24- and 57-kD parasite components as A12 on Western blots and reacted with the parasite by immunofluorescence. When tested in membrane feeding assays, these antibodies have significant suppressive effects on parasite development in the mosquito.

scholarly journals Persistent malaria transmission from asymptomatic children despite highly effective malaria control in eastern Uganda

2021 ◽  
Author(s):  
Chiara Andolina ◽  
John C Rek ◽  
Jessica J Briggs ◽  
Joseph Okoth ◽  
Alex Musiime ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Parasite Prevalence ◽  
Gametocyte Density ◽  
Targeted Interventions ◽  
School Aged Children ◽  
Feeding Experiments ◽  
Asymptomatic Children ◽  
Membrane Feeding ◽  
Asymptomatic Infections ◽  
Eastern Uganda

Background. Persistent asymptomatic Plasmodium falciparum infections are common in malaria- endemic settings, but their contribution to transmission is poorly understood. Methods. A cohort of children and adults from Tororo, Uganda was closely followed for 24 months by continuous passive surveillance and routine assessments. P. falciparum parasite density, gametocyte density and genetic composition were determined molecularly; mosquito membrane feeding assays were performed on samples from participants with symptomatic and asymptomatic infections. Findings. From October 2017 to October 2019, we followed all 531 residents from 80 households. Parasite prevalence was 5.8% by microscopy and 17.3% by PCR at enrolment and declined thereafter. We conducted 538 mosquito feeding experiments on samples from 107 individuals. Mosquito infection rates were strongly associated with gametocyte densities of participants. Considering both transmissibility of infections and their relative frequency, the estimated human infectious reservoir was primarily asymptomatic microscopy-detected infections (83.8%), followed by asymptomatic submicroscopic (15.6%) and symptomatic (0.6%) infections. Over half of the infectious reservoir was children aged 5-15 years (56.8%); individuals <5 years (27.5%) and >16 years (15.7%) contributed less. Four children were responsible for 62.6% (279/446) of infected mosquitos and were infectious at multiple timepoints. Interpretation Individuals with asymptomatic infections were important drivers of malaria transmission. School-aged children were responsible for over half of all mosquito infections, with a small minority of asymptomatic children highly infectious. Demographically targeted interventions, aimed at school-aged children, could further reduce transmission in areas under effective vector control.

The psychology of offering an apology: Understanding the barriers to apologizing and how to overcome them

2017 ◽  
Author(s):  
Karina Schumann
Keyword(s):  
Future Research ◽  
Perceived Threat ◽  
High Quality ◽  
Important Decision ◽  
Self Image

After committing an offense, a transgressor faces an important decision regarding whether and how to apologize to the person who was harmed. The actions he or she chooses to take after committing an offense can have dramatic implications for the victim, the transgressor, and their relationship. Although high quality apologies are extremely effective at promoting reconciliation, transgressors often choose to offer a perfunctory apology, withhold an apology, or respond defensively to the victim. Why might this be? In this article, I propose three major barriers to offering high quality apologies: (1) low concern for the victim or relationship, (2) perceived threat to self-image, and (3) perceived apology ineffectiveness. I review recent research examining how these barriers affect transgressors’ apology behavior, and describe insights this emerging work provides for developing methods to move transgressors towards more reparative behavior. Finally, I discuss important directions for future research.

scholarly journals Genetic changes of Plasmodium vivax tempers host tissue-specific responses in Anopheles stephensi

2021 ◽  
Author(s):  
Seena Kumari ◽  
Charu Chauhan ◽  
Sanjay Tevatiya ◽  
Deepak Singla ◽  
Tanwee Das De ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Anopheles Stephensi ◽  
Host Tissue ◽  
Genetic Changes ◽  
Tissue Specific

scholarly journals Much research, but little learned to date: A scoping review on mental health of health workers in low- and lower-middle income countries and roadmap for future research

2021 ◽  
Author(s):  
Julia Lohmann ◽  
Denny John ◽  
Aso Dzay
Keyword(s):  
Mental Health ◽  
Scoping Review ◽  
Health Workers ◽  
Tertiary Care ◽  
Psychological Wellbeing ◽  
Future Research ◽  
Measurement Tool ◽  
High Quality ◽  
Middle Income ◽  
Middle Income Countries

Abstract BackgroundSARS-CoV-2 has resulted in unprecedented research efforts on health workers’ work realities and their potential mental health impacts. To understand the latter, high-quality evidence on the baseline situation is paramount. With the aim of providing a comprehensive overview of existing evidence and to inform future research, we undertook a scoping review of the quantitative literature on mental health and psychological wellbeing of clinical skilled healthcare personnel working in all settings of care in low- and lower-middle income countries (LLMIC).MethodsWe performed a systematic search of the literature up to the end of 2019, in English or French language, in MEDLINE, EMBASE, PsychINFO, Global Health, and CAIRN. We included both studies estimating levels of mental health and studies investigating associations with other factors. We extracted data on study characteristics and methodology, and assessed the methodological quality of the included studies along nine criteria.ResultsWe found 143 relevant studies, 135 including data on mental health levels and 126 including data on associations with other factors. The studies covered 26 of the world’s 78 LLMICs, with most studies conducted in India, Nigeria, Pakistan, or Egypt, in urban secondary- and tertiary-care settings. 67% of studies assessed burnout, 25% general psychological wellbeing, and 20% other mental health outcomes. Only 19% of studies were of high quality due to shortcomings particularly in regards to sample representativeness, context-specific measurement tool validity, and reporting of methodological detail. We found much heterogeneity in investigated associated factors. Studies focused almost exclusively on potential determinants of mental health, while none linked mental health to objectively measured performance outcomes.ConclusionWe conclude that despite its impressive size, we can learn comparatively little from the current body of literature. Based on our findings, we outline areas for expansion, methodological improvement, and standardization of reporting in future research on mental health of health workers.Systematic review registrationPROSPERO no. CRD42019140036

scholarly journals Prevalence of mental disorders in South Asia: an umbrella review of systematic reviews and meta-analyses

2020 ◽  
Author(s):  
Md Mahbub Hossain ◽  
Neetu Purohit ◽  
Abida Sultana ◽  
Ping Ma ◽  
E. Lisako J. McKyer ◽  
...  
Keyword(s):  
Mental Health ◽  
Mental Disorders ◽  
South Asia ◽  
South Asian ◽  
Systematic Reviews ◽  
Mental Health Problems ◽  
Future Research ◽  
Asian Countries ◽  
Umbrella Review ◽  
Meta Analyses

Objectives: Mental disorders are highly prevalent in eight South Asian countries, yet there is a gap of a synthesized overview of the prevalence of mental disorders in this region. This umbrella review aims to summarize the prevalence of mental disorders from systematic reviews and meta-analyses of South Asian studies.Materials and methods: A systematic search of 11 major databases and additional sources was conducted until December 11, 2019. Articles were included if they were systematic reviews or meta-analyses, reported the prevalence of mental disorders, and reported primary studies conducted in South Asian countries only. Results: Among 2591 citations, a total of 23 reviews met all the criteria of this umbrella review. The synthesized findings from those reviews suggest high prevalence rates for mental disorders, including depressive disorders, anxiety disorders, mood disorders, suicidal behavior and self-harm, schizophrenia, substance use disorders, neurodevelopmental disorders, dementia, and other mental health problems. Also, findings suggest a high burden of maternal depression, psychiatric comorbidities in chronic physical illnesses, and various mental disorders among children, elderly adults, refugees, and other vulnerable populations. Most studies were from India whereas evidence from Afghanistan, Bhutan, and Maldives was limited.Conclusion: The findings of this review are constrained with heterogeneity in prevalence estimations, methodologies, sampling issues, and limitations in the existing literature, which should be addressed in future research. The evidence synthesized in this review provides national and regional overview of the prevalence of mental disorders, which may inform better policymaking and practice advancing mental health in South Asia.

scholarly journals Planting the Seeds: Orchestral Music Education as a Context for Fostering Growth Mindsets

2021 ◽  
Vol 11 ◽  
Author(s):  
Steven J. Holochwost ◽  
Judith Hill Bose ◽  
Elizabeth Stuk ◽  
Eleanor D. Brown ◽  
Kate E. Anderson ◽  
...  
Keyword(s):  
Music Education ◽  
Environmental Influence ◽  
Economic Hardship ◽  
Growth Mindset ◽  
Pedagogical Practices ◽  
Orchestral Music ◽  
Future Research ◽  
High Quality ◽  
Future Studies ◽  
Musical Growth

Growth mindset is an important aspect of children’s socioemotional development and is subject to change due to environmental influence. Orchestral music education may function as a fertile context in which to promote growth mindset; however, this education is not widely available to children facing economic hardship. This study examined whether participation in a program of orchestral music education was associated with higher levels of overall growth mindset and greater change in levels of musical growth mindset among children placed at risk by poverty. After at least 2 years of orchestral participation, students reported significantly higher levels of overall growth mindset than their peers; participating students also reported statistically significant increases in musical growth mindset regardless of the number of years that they were enrolled in orchestral music education. These findings have implications for future research into specific pedagogical practices that may promote growth mindset in the context of orchestral music education and more generally for future studies of the extra-musical benefits of high-quality music education.

scholarly journals What Are the Client, Organisational and Employee-Related Outcomes of High Quality Leadership in the Allied Health Professions? A scoping review.

2019 ◽  
Vol 14 (2) ◽  
pp. 19-30 ◽  
Author(s):  
Janice McKeever ◽  
Ted Brown
Keyword(s):  
Scoping Review ◽  
Allied Health ◽  
Grey Literature ◽  
Future Research ◽  
Reference List ◽  
High Quality ◽  
Allied Health Professionals ◽  
Consumer Expectation ◽  
Professional Groups ◽  
Modern Health Care

Background: Leadership is viewed as the panacea the complex problems in modern health care where chronic disease, contracting budgets and rising consumer expectation are challenging care provision. As the second largest workforce in Australia, Allied Health Professionals (AHP) are core contributors to health teams however they are largely absent from leadership positions and there is little evidence of their impact on client outcomes. Aim: A scoping review was carried out to synthesise evidence on the client, organisational and employee-related outcomes of high quality leadership in Allied Health. Method: A search of grey literature, peer and non-peer reviewed literature was undertaken using Embase, Emcare, SCOPUS and Psychinfo from 2010-2017. Data were sourced from journals, government reports, conference presentations and other grey literature. The reference list of key articles were hand searched for relevant research. Results: A total of 5880 articles were identified and after screening 35 articles were included for in depth review. Leadership contributed towards positive outcomes in all three domains and had influence across professional groups and services. Leaders are highly valued and respected by their teams. Allied Health leaders did not feature in any of the articles and AHP were the focus of only seven studies. The majority of articles were conference papers or case reviews that provided little robust data making it difficult to draw substantive conclusions on the outcome of AHP leadership. Conclusion: There was a lack of robust data specific to AHP leaders. Future research should attempt to gather evidence of the outcomes of AHP leadership through qualitative and quantitative means to substantiate the anecdotal evidence for high quality AHP leaders. 

scholarly journals Investigating diversity, evolution, development and physiology of red algal parasites from New Zealand

2021 ◽  
Author(s):  
◽  
Maren Preuss
Keyword(s):  
Host Species ◽  
High Throughput Sequencing ◽  
Phylogenetic Analyses ◽  
Host Cells ◽  
Gene Content ◽  
Infected Host ◽  
Parasite Development ◽  
Future Research ◽  
Mitochondrial Genomes ◽  
Red Algal

<p>Red algal parasites have evolved independently over a 100 times and grow only on other red algal hosts. Most parasites are closely related to their host based on the similarity of their reproductive structures. Secondary pit connections between red algal parasites and their hosts are used to transfer parasite organelles and nuclei into host cells. Morphological and physiological changes in infected host cells have been observed in some species. Parasite mitochondrial genomes are similar in size and gene content to free-living red algae whereas parasite plastids are highly reduced. Overall, red algal parasites are poorly studied and thus the aim of this study was to increase the general knowledge of parasitic taxa with respect to their diversity, evolutionary origin, development, physiology, and organelle evolution. Investigation of the primary literature showed that most species descriptions of red algal parasites were poor and did not meet the criteria for defining a parasitic relationship. This literature study also revealed a lack of knowledge of many key parasitic processes including early parasite development, host cell “control”, and parasite origin. Many of these poorly studied research areas were addressed in this thesis. Phylogenetic analyses, using a range of markers from all three genomes (cpDNA: rbcL, nDNA: actin, LSU rRNA; mtDNA: cox1), showed different patterns of phylogenetic relationships for the four new red algal parasites and their hosts. The parasites Phycodrys novae-zelandiophila sp. nov. and Vertebrata aterrimophila sp. nov. closest relative is its host species. Cladhymenia oblongifoliophila sp. nov. closest relative is its host species based on nuclear and mitochondrial markers whereas the plastid markers group the parasite with Cladhymenia lyallii, suggesting that the parasite plastid was acquired when previously parasitizing C. lyallii. Judithia parasitica sp. nov. grows on two Blastophyllis species but the parasites’ closest relative is the non-host species Judithia delicatissima. Developmental studies of the parasite Vertebrata aterrimophila, showed a unique developmental structure (“trunk-like” cell) not known in other parasites, plus localised infection vi and few changes in infected host cells. High-throughput-sequencing revealed mitochondrial genomes of similar size, gene content and order in the parasite Pterocladiophila hemisphaerica to its host Pterocladia lucida, and a reduced non-photosynthetic plastid in the parasite. Mitochondrial (mt) and plastid (cp) genome phylogenies placed Pterocladiophila hemisphaerica on long branches, either as sister to Ceramiales (mt) or Gracilariales (cp). Further analyses, filtering non-elevated plastid genes grouped the parasite neither with the Gracilariales (mt) or Gelidiales (cp) on shorter branches but without support. Nuclear phylogeny grouped P. hemisphaerica as sister to the Gelidiales and other red algal orders and was the only phylogenetic relationship with support. Investigations of photosystem II capacity using PAM fluorometry, and quantifying chlorophyll a content in three pigmented parasites, showed different host nutrient dependencies. Rhodophyllis parasitica and Vertebrata aterrimophila are not able to photosynthesize and are fully dependent on host nutrients. Pterocladiophila hemisphaerica is able to photosynthesize independently, even though it has a reduced non-photosynthetic plastid genome, and therefore is only partially dependent on its host. This study advances our current understanding of red algal parasites and highlights many possibilities for future research including genome evolution and understanding parasite diversity.</p>

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