Reconsidering the underestimated burden caused by neglected tropical diseases

Targeting the cysteine biosynthesis pathway in microorganisms: Mechanism, structure, and drug discovery

Owing to the global health crisis of resistant pathogenic infections, researchers are emphasizing the importance of novel prevention and control strategies. Existing antimicrobial drugs predominantly target a few pathways, and their widespread use has pervasively increased drug resistance. Therefore, it is imperative to develop new antimicrobial drugs with novel targets and chemical structures. The de novo cysteine biosynthesis pathway, one of the microbial metabolic pathways, plays a crucial role in pathogenicity and drug resistance. This pathway notably differs from that in humans, thereby representing an unexplored target for developing antimicrobial drugs. Herein, we have presented an overview of cysteine biosynthesis pathways and their roles in the pathogenicity of various microorganisms. Additionally, we have investigated the structure and function of enzymes involved in these pathways as well as have discussed drug design strategies and structure-activity relationships of the enzyme inhibitors. This review provides valuable insights for developing novel antimicrobials and offers new avenues to combat drug resistance.

Environmental influence on abundance and infection patterns of snail intermediate hosts of liver and intestinal flukes in North and Central Vietnam

Liver and intestinal flukes (LIF) are important groups of foodborne zoonotic trematodes (FZTs) in Southeast Asia, including Vietnam. Their complex life cycles require specific freshwater snail species as the obligatory first intermediate hosts. In 2019, we conducted a longitudinal study in Yen Bai and Thanh Hoa provinces in North and Central Vietnam, respectively, to investigate the diversity of LIF and their infection prevalence in relation to snail host abundance and environmental factors. Using a combination of morphological and molecular identification techniques, we identified 10 LIF species infecting 11 snail host species. We observed significant seasonal variation in the mean abundance of several snail host species, with the majority of snails collected during the spring. We also detected seasonal changes in LIF species composition, with the highest species richness reported in the spring. Clonorchis sinensis and Fasciola gigantica, two medically important human liver flukes in Asia, were found only in the spring in Yen Bai. Our study revealed that not all snail host species have the same probability of becoming infected, and we recorded seasonal variations in the prevalence of LIF infection in different snail species in relation to water parameters.

The accuracy of nucleic acid amplification tests (NAATs) in detecting human intestinal nematode infections: A protocol for a systematic review and meta-analysis

Human intestinal nematode infections are a global public health issue as they can result in considerable morbidity in infected individuals, mainly in developing countries. These infections continue to go undiagnosed, as they tend to be mainly endemic in resource-poor communities where there is a shortage of experienced laboratory staff and relevant diagnostic technologies. This is further exacerbated by the nature of intermittent shedding of eggs and larvae by these parasites. Diagnostic methods range from simple morphological identification to more specialised high-throughput sequencing technologies. Microscopy-based methods, although simple, are labour-intensive and considerably less sensitive than molecular methods which are rapid and have high levels of accuracy. Molecular methods use nucleic acid amplification (NAA) to amplify the deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) fragments of the parasite to detect and determine its presence using different technologies (NAAT). They have increased the sensitivity of detection and quantitation of intestinal nematode infections, especially in low infection intensity settings. The absence of a gold standard test limits current diagnosis and, in turn, restricts intervention measures and effective control efforts. The objective of this review is to determine the accuracy of NAATs in detecting human intestinal nematode infections using Kato-Katz as the reference test for the most common soil-transmitted helminth (STH) infections and the scotch tape test for enterobiasis and Baermann method for strongyloidiasis. Relevant studies will be identified by searches in electronic databases. Two reviewers will independently screen the literature against eligibility criteria. The methodological quality of studies will then be appraised by two reviewers using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Discrepancies will be addressed by a third reviewer. The true positives, false positives, true negatives and false negatives of all the studies will be extracted into contingency tables. In paired forest plots, study-specific sensitivity and specificity with a 95 per cent confidence interval will be displayed. The systematic review of this protocol will report the diagnostic accuracy of currently available NAATs for the detection of human intestinal nematode infections. This will help healthcare providers and administrators determine the diagnostic method to be used in different clinical and preventive settings. Trial registration: PROSPERO registration number for this protocol is CRD42022315730.

Pincer Complexes Derived from Tridentate Schiff Bases for Their Use as Antimicrobial Metallopharmaceuticals

Within the current challenges in medicinal chemistry, the development of new and better therapeutic agents effective against infectious diseases produced by bacteria, fungi, viruses, and parasites stands out. With chemotherapy as one of the main strategies against these diseases focusing on the administration of organic and inorganic drugs, the latter is generally based on the synergistic effect produced by the formation of metal complexes with biologically active organic compounds. In this sense, Schiff bases (SBs) represent and ideal ligand scaffold since they have demonstrated a broad spectrum of antitumor, antiviral, antimicrobial, and anti-inflammatory activities, among others. In addition, SBs are synthesized in an easy manner from one-step condensation reactions, being thus suitable for facile structural modifications, having the imine group as a coordination point found in most of their metal complexes, and promoting chelation when other donor atoms are three, four, or five bonds apart. However, despite the wide variety of metal complexes found in the literature using this type of ligands, only a handful of them include on their structures tridentate SBs ligands and their biological evaluation has been explored. Hence, this review summarizes the most important antimicrobial activity results reported this far for pincer-type complexes (main group and d-block) derived from SBs tridentate ligands.

Multiplex peptide microarray profiling of antibody reactivity against neglected tropical diseases derived B-cell epitopes for serodiagnosis in Zimbabwe

Introduction

Peptides (B-cell epitopes) have broad applications in disease diagnosis and surveillance of pathogen exposure. In this framework, we present a pilot study to design and produce a peptide microarray for the integrated surveillance of neglected tropical diseases. The peptide microarray was evaluated against peptides derived from Ascaris lumbricoides, Necator americanus, Schistosoma haematobium, Schistosoma mansoni, Trichuris trichiura, Bacillus anthracis, Mycobacterium leprae, Wuchereria bancrofti, Rabies lyssavirus, Chlamydia trachomatis and Trypanosoma brucei.

Methods

S. haematobium was diagnosed using the urine filtration technique. S. mansoni, A. lumbricoides, N. americanus and T. trichiura were diagnosed using the Kato Katz and formal ether concentration techniques. Immunogenic peptides were retrieved from the Tackling Infection to Benefit Africa infectious diseases epitope microarray. Further peptides were predicted using ABCpred. IgG and IgM reactivity against the derived peptides were evaluated using peptide microarray multiplex immunoassays. Positive response was defined as fluorescence intensity ≥ 500 fluorescence units. Immunodominant peptides were identified using color-coded heat maps and bar graphs reflecting the obtained fluorescence signal intensities. Receiver Operating Characteristic analysis and Mann-Whitney-U test were performed to determine the diagnostic validity of the peptides.

Results

Species-specific responses with at least one peptide derived from each NTD pathogen were observed. The reactive peptides included; for S. haematobium, XP_035588858.1-206-220 and XP_035588858.1-206-220 immunodominant for IgG and IgM respectively, for S. mansoni, P20287.1-58-72 immunodominant for both antibodies and for T. trichiura, CDW52482.1-326-340 immunodominant for IgG and CDW57769.1-2017-2031 and CDW57769.1-1518-1532 immunodominant for IgM. According to ROC analysis most of the peptides selected were inaccurate; with AUC < 0.5. Some peptides had AUC values ranging from 0.5 to 0.5875 for both IgM and IgG suggesting no discrimination.

Conclusion

Multiplex peptide microarrays are a valuable tool for integrated NTDs surveillance and for screening parasites exposure in endemic areas. Species sero-reactivity observed in the study maybe indicative of exposure to the different NTDs parasites. However, although peptides with the least cross reactivity were selected there is need to validate the sero-reactivity with recombinant antigens and immune-blotting techniques such as western blotting.

Effectiveness of self-care interventions for integrated morbidity management of skin neglected tropical diseases in Anambra State, Nigeria

Background

Lymphatic filariasis (LF), Buruli ulcer (BU) and leprosy are neglected tropical diseases (NTDs) of the skin co-endemic in some communities in Nigeria. Not enough is known about the effectiveness of integrated morbidity management and disability prevention in people with these conditions. An integrated self-care intervention was carried out for people with these skin NTDs in two endemic communities of Anambra state, Nigeria. The objective of the study was to assess the effectiveness of self-care practices on costs of care, disability status and health-related quality of life.

Methods

This study utilised a quasi-experimental pre-test/post-test design to assess the effectiveness of the self-care interventions for people affected by NTDs to care for these impairments at home. Data were collected using questionnaires administered at the beginning and at the end of the intervention on monthly cost of morbidity care, and on participants’ disability status and their quality of life (QoL). Focus group discussions (FGDs) were held with both the participants and healthcare workers at follow-up.

Results

Forty-eight participants were recruited. Thirty participants (62.5%) continued the self-care interventions until the end of the project. Of those, 25 (83%) demonstrated improvement from their baseline impairment status. The mean household costs of morbidity care per participant decreased by 66% after the intervention, falling from US$157.50 at baseline to US$53.24 after 6 months of self-care (p = 0.004). The mean disability score at baseline was 22.3; this decreased to 12.5 after 6 months of self-care (p < 0.001). Among the 30 participants who continued the interventions until the end of the project, 26 (86.7%) had severe disability score (i.e. a score of 10–46) at baseline, and the number with severe disability fell to 18 (60%) of the 30 after the intervention. The mean QoL score increased from 45.7 at baseline to 57.5 at the end of the intervention (p = 0.004).

Conclusions

The 6-month self-care intervention for participants affected by BU, leprosy, or LF led to lower costs of care (including out-of-pocket costs and lost earnings due to morbidity), improved QoL scores, and reduced disability status.

Trial registration

ISRCTN Registry: ISRCTN20317241; 27/08/2021, Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11729-1.

Clinical utility of peptide microarrays in the serodiagnosis of neglected tropical diseases in sub-Saharan Africa: protocol for a diagnostic test accuracy systematic review

INTRODUCTION

Neglected tropical diseases tend to cluster in the same poor populations and, to make progress with their control, they will have to be dealt with in an integrated manner. Peptide microarrays may be a solution to these problems, where diagnosis for co-infection can be detected simultaneously using the one tool. A meta-analysis using hierarchical models will be performed to assess the diagnostic accuracy of peptide microarrays for detecting schistosomiasis (Schistosoma mansoni and S. haematobium), soil-transmitted helminths (Trichuris trichiura, Ascaris lumbricoides and Necator americanus), trachoma (Chlamydia trachomatis), lymphatic filariasis (Wuchereria bancrofti) and onchocerciasis (Onchocerca volvulus) in people residing in sub-Saharan Africa.

METHODS AND ANALYSIS

A comprehensive search of the following databases will be performed: Cochrane Infectious Diseases Group Specialised Register, PubMed, EMBASE and The Web of Science. Studies comparing peptide microarrays with a reference standard from a random or consecutive series of patients will be included in the study. Two review authors will independently screen titles and abstracts for relevance, assess full-text articles for inclusion and carry out data extraction using a tailored data extraction form. The quality Assessment of Diagnostic Accuracy Studies-2 tool will be used to assess the quality of the selected studies. The bivariate model and the hierarchical summary receiver operating characteristic curve model will be performed to evaluate the diagnostic accuracy of the peptide microarrays. Meta-regression analyses will be performed to investigate heterogeneity across studies.

ETHICS AND DISSEMINATION

There is no requirement for ethical approval because the work will be carried out using previously published data, without human beings involvement. Findings will be disseminated through peer-reviewed publication and in conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42020175145.

Insights on foodborne zoonotic trematodes in freshwater snails in North and Central Vietnam

Foodborne zoonotic trematode (FZT) infections are common neglected tropical diseases in Southeast Asia. Their complicated life cycles involve freshwater snails as intermediate hosts. A cross-sectional study was conducted in Yen Bai and Thanh Hoa provinces in North and Central Vietnam, to investigate the diversity of cercariae of potential FZT and to construct the phylogenetic relationship of trematode cercariae based on the Internal Transcribed Spacer 2 (ITS2) region. Among 17 snail species collected from various habitats, 13 were infected by 10 cercarial groups among which parapleurolophocercous, pleurolophocercous, and echinostome cercariae were of zoonotic importance. The monophyletic tree separated cercarial sequences into different groups following the description of the cercariae families in which Haplorchidae, Opisthorchiidae, Echinochasmidae, and Echinostomatidae are important families of FZT. The overall prevalence was different among snail species and habitats and showed a seasonal trend. Parapleurolophocercous and echinostome cercariae emerged as the most common cercariae in snails in Yen Bai, while monostome, echinostome, and megalura cercariae were most common in Thanh Hoa. Using a molecular approach, we identified Parafossarulus striatulus as the first intermediate snail host of Clonorchis sinensis in Thac Ba Lake. Melanoides tuberculata and Bithynia fuchsiana were we identified preferred intermediate snail hosts of a diverse range of trematode species including intestinal flukes (i.e., Haplorchis pumilio and Echinochasmus japonicus) in Yen Bai and Thanh Hoa, respectively.

Evaluating farm-level livestock interventions in low-income countries: a scoping review of what works, how, and why

Livestock interventions can improve nutrition, health, and economic well-being of communities. The objectives of this review were to identify and characterize livestock interventions in developing countries and to assess their effectiveness in achieving development outcomes. A scoping review, guided by a search strategy, was conducted. Papers needed to be written in English, published in peer-reviewed journals, and describe interventions in animal health and production. Out of 2739 publications systematically screened at the title, abstract, and full publication levels, 70 met our inclusion criteria and were considered in the study. Eight relatively high-quality papers were identified and added, resulting in 78 reviewed publications. Only 15 studies used randomized controlled trial designs making it possible to confidently link interventions with the resulting outcomes. Eight studies had human nutrition or health as outcomes, 11 focused on disease control, and four were on livestock production. Eight interventions were considered successful, but only four were scalable. We found good evidence that livestock-transfer programs, leveraging livestock products for nutrition, and helping farmers manage priority diseases, can improve human well-being. Our report highlights challenges in garnering evidence for livestock interventions in developing countries and provides suggestions on how to improve the quantity and quality of future evaluations.

Declining antibody levels to Trypanosoma cruzi correlate with polymerase chain reaction positivity and electrocardiographic changes in a retrospective cohort of untreated Brazilian blood donors

Background

Although infection with Trypanosoma cruzi is thought to be lifelong, less than half of those infected develop cardiomyopathy, suggesting greater parasite control or even clearance. Antibody levels appear to correlate with T. cruzi (antigen) load. We test the association between a downwards antibody trajectory, PCR positivity and ECG alterations in untreated individuals with Chagas disease.

Methodology/Principal findings

This is a retrospective cohort of T. cruzi seropositive blood donors. Paired blood samples (index donation and follow-up) were tested using the VITROS Immunodiagnostic Products Anti-T.cruzi (Chagas) assay (Ortho Clinical Diagnostics, Raritan NJ) and PCR performed on the follow-up sample. A 12-lead resting ECG was performed. Significant antibody decline was defined as a reduction of > 1 signal-to-cutoff (S/CO) unit on the VITROS assay. Follow-up S/CO of < 4 was defined as borderline/low. 276 untreated seropositive blood donors were included. The median (IQR) follow-up was 12.7 years (8.5–16.9). 56 (22.1%) subjects had a significant antibody decline and 35 (12.7%) had a low/borderline follow-up result. PCR positivity was lower in the falling (26.8% vs 52.8%, p = 0.001) and low/borderline (17.1% vs 51.9%, p < 0.001) antibody groups, as was the rate of ECG abnormalities. Falling and low/borderline antibody groups were predominantly composed of individuals with negative PCR and normal ECG findings: 64% and 71%, respectively.

Conclusions/Significance

Low and falling antibody levels define a phenotype of possible spontaneous parasite clearance.

Infection with the single-celled parasite Trypanosoma cruzi (Chagas disease) is thought to be lifelong. However, only a third of infected people develop Chagas cardiomyopathy–the main disease manifestation. This may reflect the different extent to which individuals control the parasite, with some potentially clearing it entirely. In chronically infected immunocompetent patients, a marker of parasite burden is the quantity of antibody against T. cruzi in the blood: more parasite, more immune stimulation, more antibody. In this study we show how antibody levels change over many years in a cohort of untreated patients with Chagas disease. We find that among individuals with falling or low/borderline antibody levels there was a lower rate of parasite detection in the blood and a lower rate of cardiomyopathy. 60% of subjects with falling antibody levels had no evidence of active disease, twice as many as among patients with other antibody trajectories (stable or rising). Our findings support an account of the natural history of Chagas disease in which a proportion of those infected achieve a greater control of the parasite, with some individuals potentially clearing it completely.

Gut Dysbiosis in Chagas Disease. A Possible Link to the Pathogenesis

Chagas disease is caused by the flagellate protozoan Trypanosoma cruzi. Cardiomyopathy and damage to gastrointestinal tissue are the main disease manifestations. There are data suggesting that the immune response to T. cruzi depends on the intestinal microbiota. We hypothesized that Chagas disease is associated with an altered gut microbiome and that these changes are related to the disease phenotype. The stool microbiome from 104 individuals, 73 with Chagas disease (30 with the cardiac, 11 with the digestive, and 32 with the indeterminate form), and 31 healthy controls was characterized using 16S rRNA amplification and sequencing. The QIIME (Quantitative Insights Into Microbial Ecology) platform was used to analyze the data. Alpha and beta diversity indexes did not indicate differences between the groups. However, the relative abundance of Verrucomicrobia, represented primarily by the genus Akkermansia, was significantly lower in the Chagas disease groups, especially the cardiac group, compared to the controls. Furthermore, differences in the relative abundances of Alistipes, Bilophila, and Dialister were observed between the groups. We conclude that T. cruzi infection results in changes in the gut microbiome that may play a role in the myocardial and intestinal inflammation seen in Chagas disease.

Effectiveness of Mass Drug Administration on Neglected Tropical Diseases in Schoolchildren in Zanzibar, Tanzania

Soil-transmitted helminths and Schistosoma haematobium affect more than 3 billion people globally and mainly occur in sub-Saharan Africa. The present study assessed the overall infection status of a 1716-student cohort of school-children in Zanzibar and applied mass drug administration (MDA) to the cohort from 2007 to 2009. Schools in Pemba, Zanzibar, had a much higher prevalence of soil-transmitted helminth infections than those in Unguja, and the Chaani, Ghana, and Machui schools of Unguja exhibited high S. haematobium infection rates. The MDA program only partially controlled parasite infections, owing to high rates of re-infection. The infection rate of S. haematobium across all 10 schools, for example, was only reduced by 1.8%, and even this change not significant, even though the S. haematobiuminfection rates of the Chaani and Mzambarauni schools were significantly reduced from 64.4 and 23.4%, respectively, at the first screening, to 7.3 and 2.3% at the last screening. The overall infection rate of Ascaris lumbricoides was reduced from 36.0% at the first screening to 22.6% at the last screening. However, the infection rates for both Trichuris trichiuraand hookworm were generally unaffected by MDA. In the future, parasite control programs should involve strategically designed MDA schedules and holistic intervention (e.g., sanitation improvement, hygiene behavior changes, and control of intermediated hosts).

Investigating barriers and challenges to the integrated management of neglected tropical skin diseases in an endemic setting in Nigeria

BACKGROUND

There is a dearth of experience in and evidence for cost-effective integrated community-based management of skin neglected tropical diseases (NTDs). The objective of this study was to assess the knowledge, attitude and care-seeking practices including self-care with a view to introducing appropriate community-based interventions for skin NTDs in an endemic setting in Southern Nigeria.

METHODS/PRINCIPAL FINDINGS

This exploratory study adopted a mixed-methods design consisting of cross-sectional surveys of community members and health workers using interviewer-administered questionnaires; and focus group discussions (FGDs) with community members, health care workers and patients with NTDs in Anambra State, Nigeria. The survey was completed by 353 community members (61.8% female) and 15 health care workers (100.0% female). A total of 52 individuals participated in six FGDs. Of the community members, 236 (66.9%) had heard or seen a case of leprosy; 324 (91.8%) and 131 (37.5%) had heard or seen a case of Buruli ulcer and lymphatic filariasis, respectively. Again, 213 (60.3%) of the respondents reported that the diseases were caused by witchcraft or curse. As regards prevention, 241 (68.3%) suggested avoiding handshake with affected persons. Up to 223 (63.2%) of respondents strongly agreed to the seriousness of skin NTDs in their community. Meanwhile, 272 (77.1%) of the respondents believed that the transmission of these skin NTDs can be prevented. Furthermore, 324 (91.7%) desired active community engagement for control of skin NTDs. Regarding community care seeking practices, 197 (55.8%) would first visit the health centre/hospital, followed by 91 (25.8%) traditional healer/herbalist and 35 (9.9%) pharmacy/patent medicine vendor if they develop a skin NTD. Overall, 332 (94.1%) of respondents expressed interest in being taught self-care practices for skin NTDs. Out of 15 healthcare workers, 13 (86.7%) were able to correctly diagnose two of these skin NTDs and 10 (66.7%) would encourage patients to practice self-care. Prominent themes in the FGDs were belief in witchcraft and herbal remedies; as well as the occurrence of physical, social and economic distress.

CONCLUSIONS

Our study helped quantify the information gaps that need to be addressed in order to create demand for integrated skin NTDs services in an endemic setting in Nigeria. Individual, structural and socioeconomic challenges to access and delivery of services were identified. Community and health care workers' empowerment and engagement through outreach and regular training, respectively may alleviate these challenges.

Quantifying the socio-economic impact of leg lymphoedema on patient caregivers in a lymphatic filariasis and podoconiosis co-endemic district of Ethiopia

Background

Lymphoedema caused by lymphatic filariasis (LF) or podoconiosis can result in physical disability and social exclusion, which is exacerbated by painful acute dermatolymphangioadenitis (ADLA) episodes. These conditions have a significant impact on patients, however, little is known about the indirect effects on their caregivers. This study, therefore, aimed to determine the impact on caregivers for patients with leg lymphoedema in a co-endemic district of Ethiopia.

Methodology/Principal findings

A cross-sectional survey of lymphoedema patients and their caregivers was conducted using semi-structured questionnaires in the Southern Nation Nationalities Peoples Region (SNNPR) of Ethiopia. Lymphoedema patient information on clinical severity (mild, moderate, severe), frequency of ADLAs, their socio-demographic characteristics and the identity of main caregiver(s) was collected. Caregiver information on socio-demographic characteristics, types of care provided, their quality of life (QoL) measured across nine domains, and productivity was collected, with key indicators compared in the presence and absence of patients’ ADLAs.

A total of 73 patients and 76 caregivers were included. Patients were grouped by mild/moderate (n = 42, 57.5%) or severe (n = 31, 42.5%) lymphoedema, and reported an average of 6.1 (CI± 2.18) and 9.8 (CI± 3.17) ADLAs respectively in the last six months. A total of 48 (65.8%) female and 25 (34.2%) male patients were interviewed. Caregivers were predominately male (n = 45, 59.2%), and spouses formed the largest caregiving group for both female and male patients.

In the absence of an ADLA, most caregivers (n = 42, 55.2%) did not provide care, but only one caregiver did not provide care during an ADLA. In the absence of an ADLA, the average time (hour:minute) spent by mild/moderate (00:17, CI: ± 00:08) and severe (00:10, CI: ± 00:07) patient caregiver per task was minimal. The time mild/moderate (00:47, CI: ± 00:11) and severe (00:51, CI: ± 00:16) patient caregivers spent per task significantly increased in the presence of an ADLA. In addition, caregivers’ QoL was negatively impacted when patients experienced an ALDA, and they had to forfeit an average of 6 to 7 work/school days per month.

Conclusion/Significance

Lymphoedema and ADLAs impact negatively on patients’ and their caregivers’ lives. This emphasises the importance of increasing access to effective morbidity management and disability prevention services to reduce the burden and help to address the Sustainable Development Goal (SDG) 5, target 5.4, which seeks to recognise and value unpaid care and domestic work.

Lymphatic filariasis and podoconiosis can result in chronic severe lymphoedema of the limbs, which is aggravated by frequent painful episodes of acute bacterial infection known as ‘acute attacks’. The debilitating impact of these conditions on patients are well documented, however, the extent to which the hardship extends to their caregivers is unknown. To address this knowledge gap, a survey of 73 lymphoedema patients and their caregivers was conducted in an endemic region of Ethiopia. Patients were found to be predominately female and caregivers predominately male, mostly spouses. Caregivers provided a wide range of care, and the type, frequency and time spent on tasks significantly increased when patients experienced an acute attack. Caregivers reported a negative impact on their quality of life and provided care for an average of 15 days and forfeited an average of 7 days of work or school per month. This study has revealed a previously hidden burden of lymphoedema that not only affects patients, but their caregivers who are mostly family members. This emphasises the importance of increasing access to effective morbidity management and disability prevention programmes to reduce the burden and help to address the Sustainable Development Goal (SDG) 5, target 5.4, which seeks to recognise and value unpaid and domestic work.

Zoonotic pathogens in urban animals: Enough research to protect the health of the urban population?

With more than half of the global population living in cities, the urban areas are also teeming with animals, including peridomestic wildlife, pets, and livestock. Urban animals may carry zoonotic pathogens, and crowded conditions in cities can increase the risk for the human population. We used a systematic approach to screen two publication databases as well as gray literature, and quantified the studies conducted on zoonoses in urban animals with respect to the geographic distribution, the host animal and pathogens. Out of 876 references found, 93 were included into final data extraction. Few studies were from the rapidly expanding cities in low- and middle-income countries where urban livestock-keeping is far more prominent than in high-income countries. Most studies were performed in peridomestic wildlife and pets, less in livestock. The most common category of pathogens studied were gastrointestinal parasites followed by gastrointestinal bacteria, whereas studies on some other zoonoses internationally recognized as critical for public health were few or absent. In conclusion, to mitigate the risks of emergence of zoonoses from urban animals this review highlights the research gaps on zoonoses, particularly in livestock in rapidly growing tropical cities and a more comprehensive inclusion of pathogens prioritized by WHO and OIE.

Chagas Disease: From Discovery to a Worldwide Health Problem

Carlos Chagas discovered American trypanosomiasis, also named Chagas disease (CD) in his honor, just over a century ago. He described the clinical aspects of the disease, characterized by its etiological agent (Trypanosoma cruzi) and identified its insect vector. Initially, CD occurred only in Latin America and was considered a silent and poorly visible disease. More recently, CD became a neglected worldwide disease with a high morbimortality rate and substantial social impact, emerging as a significant public health threat. In this context, it is crucial to better understand better the epidemiological scenarios of CD and its transmission dynamics, involving people infected and at risk of infection, diversity of the parasite, vector species, and T. cruzi reservoirs. Although efforts have been made by endemic and non-endemic countries to control, treat, and interrupt disease transmission, the cure or complete eradication of CD are still topics of great concern and require global attention. Considering the current scenario of CD, also affecting non-endemic places such as Canada, USA, Europe, Australia, and Japan, in this review we aim to describe the spread of CD cases worldwide since its discovery until it has become a global public health concern.

Outbreak of scabies among preschool children, Accra, Ghana, 2017

Background

Scabies occurs worldwide with a prevalence between 0.3 and 46.0%. In Ghana, even though a 5.1% proportion of scabies was reported in a retrospective review of skin diseases at the Korle Bu Teaching Hospital, the nationwide prevalence of scabies is unknown. Overall, its burden is higher in tropical regions. Scabies outbreaks mostly occur among children, the elderly in nursing homes, and prison inmates. Even though primary scabies hardly results in mortalities, the pain, itch, and systemic complications from secondary bacterial infections account for about 1.5 million years lived with disabilities. We investigated a scabies outbreak among school children in Ghana to determine its magnitude, stop the outbreak, and institute preventive measures to minimize risks of future outbreaks.

Methods

The investigation was conducted between March 14 and May 17, 2017 among pupils of Presbyterian Secondary Staff Basic School in Accra. We defined a case as a school child who on clinical examination, had an intensely pruritic rash on at least one typical predilection site with or without a burrow, or positive skin scrapings on microscopy. We screened and line listed cases, performed laboratory investigations on skin scrapings and wound swaps, and conducted an environmental assessment. We performed descriptive statistics on data, and calculated attack rate ratios (ARR) at 95% confidence level.

Results

Of 823 preschool children screened, 92 were cases. Median age of cases was 4 years (range 2–7 years) and their modal age was 3 years. The overall attack rate was 11.2% (92/823). The sex specific attack rate was 11.5% for males, and 10.8% for females (ARR: 0.93; CI: 0.67–1.28). Compared with the least affected class (crèche), the nursery one class was worst affected (ARR: 5.14; CI: 3.44–7.50). On microscopy, all skin scrapings were negative for scabies. Staphylococcus aureus and Streptococcus spp. were isolated from secondarily infected scabies lesions.

Conclusions

A scabies outbreak with a propagated source occurred among preschool children. The 3-year-old pupils were most affected. It was controlled by mass treatment with benzyl benzoate and health education. Classrooms and sleeping mats were disinfected. We recommended the decongestion of classrooms and discouraged sharing of sleeping mats.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7085-6) contains supplementary material, which is available to authorized users.

Vanadium: History, chemistry, interactions with α-amino acids and potential therapeutic applications

In the last 30 years, since the discovery that vanadium is a cofactor found in certain enzymes of tunicates and possibly in mammals, different vanadium-based drugs have been developed targeting to treat different pathologies. So far, the in vitro studies of the insulin mimetic, antitumor and antiparasitic activity of certain compounds of vanadium have resulted in a great boom of its inorganic and bioinorganic chemistry. Chemical speciation studies of vanadium with amino acids under controlled conditions or, even in blood plasma, are essential for the understanding of the biotransformation of e.g. vanadium antidiabetic complexes at the physiological level, providing clues of their mechanism of action. The present article carries out a bibliographical research emphaticizing the chemical speciation of the vanadium with different amino acids and reviewing also some other important aspects such as its chemistry and therapeutical applications of several vanadium complexes.

Neglected tropical diseases and vitamin B12: a review of the current evidence

Vitamin B12 deficiency is an urgent public health problem that disproportionately affects individuals in low- and middle-income settings, where the burden of neglected tropical diseases (NTDs) is also unacceptably high. Emerging evidence supports a potential role of micronutrients in modulating the risk and severity of NTDs. However, the role of vitamin B12 in NTD pathogenesis is unknown. This systematic review was conducted to evaluate the evidence on the role of vitamin B12 in the etiology of NTDs. Ten studies were included in this review: one study using an in vitro/animal model, eight observational human studies and one ancillary analysis conducted within an intervention trial. Most research to date has focused on vitamin B12 status and helminthic infections. One study examined the effects of vitamin B12 interventions in NTDs in animal and in vitro models. Few prospective studies have been conducted to date to examine the role of vitamin B12 in NTDs. The limited literature in this area constrains our ability to make specific recommendations. Larger prospective human studies are needed to elucidate the role of vitamin B12 in NTD risk and severity in order to inform interventions in at-risk populations.

Pathogens transmitted in animal feces in low- and middle-income countries

Animals found in close proximity to humans in low-and middle-income countries (LMICs) harbor many pathogens capable of infecting humans, transmissible via their feces. Contact with animal feces poses a currently unquantified-though likely substantial-risk to human health. In LMIC settings, human exposure to animal feces may explain some of the limited success of recent water, sanitation, and hygiene interventions that have focused on limiting exposure to human excreta, with less attention to containing animal feces. We conducted a review to identify pathogens that may substantially contribute to the global burden of disease in humans through their spread in animal feces in the domestic environment in LMICs. Of the 65 potentially pathogenic organisms considered, 15 were deemed relevant, based on burden of disease and potential for zoonotic transmission. Of these, five were considered of highest concern based on a substantial burden of disease for which transmission in animal feces is potentially important: Campylobacter, non-typhoidal Salmonella (NTS), Lassa virus, Cryptosporidium, and Toxoplasma gondii. Most of these have a wide range of animal hosts, except Lassa virus, which is spread through the feces of rats indigenous to sub-Saharan Africa. Combined, these five pathogens cause close to one million deaths annually. More than half of these deaths are attributed to invasive NTS. We do not estimate an overall burden of disease from improperly managed animal feces in LMICs, because it is unknown what proportion of illnesses caused by these pathogens can be attributed to contact with animal feces. Typical water quantity, water quality, and handwashing interventions promoted in public health and development address transmission routes for both human and animal feces; however, sanitation interventions typically focus on containing human waste, often neglecting the residual burden of disease from pathogens transmitted via animal feces. This review compiles evidence on which pathogens may contribute to the burden of disease through transmission in animal feces; these data will help prioritize intervention types and regions that could most benefit from interventions aimed at reducing human contact with animal feces.

Socioeconomic benefit to individuals of achieving 2020 targets for four neglected tropical diseases controlled/eliminated by innovative and intensified disease management: Human African trypanosomiasis, leprosy, visceral leishmaniasis, Chagas disease

BACKGROUND

The control or elimination of neglected tropical diseases (NTDs) has targets defined by the WHO for 2020, reinforced by the 2012 London Declaration. We estimated the economic impact to individuals of meeting these targets for human African trypanosomiasis, leprosy, visceral leishmaniasis and Chagas disease, NTDs controlled or eliminated by innovative and intensified disease management (IDM).

METHODS

A systematic literature review identified information on productivity loss and out-of-pocket payments (OPPs) related to these NTDs, which were combined with projections of the number of people suffering from each NTD, country and year for 2011-2020 and 2021-2030. The ideal scenario in which the WHO's 2020 targets are met was compared with a counterfactual scenario that assumed the situation of 1990 stayed unaltered. Economic benefit equaled the difference between the two scenarios. Values are reported in 2005 US$, purchasing power parity-adjusted, discounted at 3% per annum from 2010. Probabilistic sensitivity analyses were used to quantify the degree of uncertainty around the base-case impact estimate.

RESULTS

The total global productivity gained for the four IDM-NTDs was I$ 23.1 (I$ 15.9 -I$ 34.0) billion in 2011-2020 and I$ 35.9 (I$ 25.0 -I$ 51.9) billion in 2021-2030 (2.5th and 97.5th percentiles in brackets), corresponding to US$ 10.7 billion (US$ 7.4 -US$ 15.7) and US$ 16.6 billion (US$ 11.6 -US$ 24.0). Reduction in OPPs was I$ 14 billion (US$ 6.7 billion) and I$ 18 billion (US$ 10.4 billion) for the same periods.

CONCLUSIONS

We faced important limitations to our work, such as finding no OPPs for leprosy. We had to combine limited data from various sources, heterogeneous background, and of variable quality. Nevertheless, based on conservative assumptions and subsequent uncertainty analyses, we estimate that the benefits of achieving the targets are considerable. Under plausible scenarios, the economic benefits far exceed the necessary investments by endemic country governments and their development partners. Given the higher frequency of NTDs among the poorest households, these investments represent good value for money in the effort to improve well-being, distribute the world's prosperity more equitably and reduce inequity.

Trematoda (flukes)

The class Trematoda is the largest group of Platyhelminths and includes two subclasses: Aspidogastrea and Digenea. Trematodes, and particularly Digeneans, is a large group of organisms with significant medical and veterinary interest. Over 100 species of digenetic trematodes have been reported infecting humans. Although the significant mortality and morbidity that some of these infections cause, they are among the most neglected tropical diseases. Apart from their impact in public and animal health, the Digenea constitutes an intriguing group of organisms that has a vast interest in experimental biology. Systematics and taxonomy of this group constitute a challenge for biologists in relation to the difficulty entailed in the establishment of phylogenetic relationships between trematodes and the determination of valid diagnostic features. Moreover, their complex life cycles, using at least two hosts and alternating free-living and parasitic stages or sexual and asexual multiplication, constitute a paradigm of how organisms can evolve to become adapted to different biotic and abiotic environments to enhance survival. In this review, we briefly summarize the major features of trematodes in relation to both biological and medical areas.

Association between intestinal helminth infections and mid-upper-arm circumference among children in Sri Lanka: A cross-sectional study

Intestinal helminth infections constitute a major health problem in low socio-economic communities worldwide. A cross-sectional study was conducted in children aged between 12 and 60 months. A structured questionnaire was used to collect socio-demographic data and stool samples were subjected to direct smear, stained with Lugol's iodine, and formaldehyde-ether concentration techniques to determine the prevalence of intestinal helminth infections. The circumference of each child's left mid upper arm (MUAC) was measured using standard procedures. Two hundred and six children with a mean MUAC of 14.7 cm (SD ± 1.1) were assessed from September to December 2014. The prevalence of acute energy undernutrition was 6.3% (13/206). All of them had moderate acute undernutrition and no cases of severe acute undernutrition. Paternal occupation was significantly associated with MUAC. Intestinal helminth infections were detected in 12.6% of children. Four species of parasites were identified; Ascaris lumbricoides (9.7%) followed by Enterobius vermicularis (1.5%), Trichuris trichiura (1.0%) and hookworms (1.0%). Uninfected children aged between 1 and 2 years showed significantly higher MUAC than infected children. No statistically significant association was detected between the severity of intestinal helminth infections and MUAC. Although intestinal helminth infections are a major public health problem in this community, they are not related to MUAC. Future research, providing more insight into the nutritional impact of intestinal helminth infections, is required to determine the association between parasitic infections and physical growth in this community.

New alkenyl derivative from Piper malacophyllum and analogues: Antiparasitic activity against Trypanosoma cruzi and Leishmania infantum

Alkylphenols isolated from Piper malacophyllum (Piperaceae), gibbilimbols A and B, showed interesting activity against the parasites Trypanosoma cruzi and Leishmania infantum. In continuation to our previous work, a new natural product from the essential oil of the leaves of P. malacophyllum was isolated, the 5-[(3E)-oct-3-en-1-il]-1,3-benzodioxole, and also a new set of five compounds was prepared. The antiparasitic activity of the natural product was evaluated in vitro against these parasites, indicating potential against the promastigote/trypomastigote/amastigote forms (IC₅₀ 32-83 μm) of the parasites and low toxicity (CC₅₀  > 200 μm) to mammalian cells. The results obtained to the synthetic compounds indicated that the new derivatives maintained the promising antiparasitic activity, but the cytotoxicity was considerably lowered. The amine derivative LINS03011 displayed the most potent IC₅₀ values (13.3 and 16.7 μm) against amastigotes of T. cruzi and L. infantum, respectively, indicating comparable activity to the phenolic prototype LINS03003, with threefold decreased (CC₅₀ 73.5 μm) cytotoxicity, leading the selectivity index (SI) towards the parasites up to 24.5. In counterpart, LINS03011 has not shown membrane disruptor activity in SYTOX Green model. In summary, this new set showed the hydroxyl is not essential for the antiparasitic activity, and its substitution could decrease the toxicity to mammalian cells.

Cost-effectiveness of meglumine antimoniate versus miltefosine caregiver DOT for the treatment of pediatric cutaneous leishmaniasis

BACKGROUND

Oral miltefosine has been shown to be non-inferior to first-line, injectable meglumine antimoniate (MA) for the treatment of cutaneous leishmaniasis (CL) in children. Miltefosine may be administered via in-home caregiver Directly Observed Therapy (cDOT), while patients must travel to clinics to receive MA. We performed a cost-effectiveness analysis comparing miltefosine by cDOT versus MA for pediatric CL in southwest Colombia.

METHODOLOGY/PRINCIPLE FINDINGS

We developed a Monte Carlo model comparing the cost-per-cure of miltefosine by cDOT compared to MA from patient, government payer, and societal perspectives (societal = sum of patient and government payer perspective costs). Drug effectiveness and adverse events were estimated from clinical trials. Healthcare utilization and costs of travel were obtained from surveys of providers and published sources. The primary outcome was cost-per-cure reported in 2015 USD. Treatment efficacy, costs, and adherence were varied in sensitivity analysis to assess robustness of results. Treatment with miltefosine resulted in substantially lower cost-per-cure from a societal and patient perspective, and slightly higher cost-per-cure from a government payer perspective compared to MA. Mean societal cost-per-cure were $531 (SD±$239) for MA and $188 (SD±$100) for miltefosine, a mean cost-per-cure difference of +$343. Mean cost-per-cure from a patient perspective were $442 (SD ±$233) for MA and $30 (SD±$16) for miltefosine, a mean difference of +$412. Mean cost-per-cure from a government perspective were $89 (SD±$55) for MA and $158 (SD±$98) for miltefosine, with a mean difference of -$69. Results were robust across a variety of assumptions in univariate and multi-way analysis.

CONCLUSIONS/SIGNIFICANCE

Treatment of pediatric cutaneous leishmaniasis with miltefosine via cDOT is cost saving from patient and societal perspectives, and moderately more costly from the government payer perspective compared to treatment with MA. Results were robust over a range of sensitivity analyses. Lower drug price for miltefosine could result in cost saving from a government perspective.

Environmental determinants of aplastic anemia in Pakistan: a case-control study

Aim

Aplastic anemia (AA) affects the Asian population two to three fold more than people in other regions. Besides the host genetics and socioeconomic status, several other environmental exposures have been linked with an AA etiology. We aimed to examine the association of various environmental exposures with AA occurrence among Pakistani individuals.

Subjects and methods

A case-control study was conducted in Karachi, Pakistan, where cases (diagnosed AA patients) were selected from the National Institute of Blood Disease and Bone Marrow Transplantation (NIBD), while for each case, a single control (who was free of AA and visited the outpatient department of the same hospital for the treatment of minor ailments) was selected matched by age and sex. A total of 428 participants were included in this study with equal proportions of cases and controls. Information related to disease characteristics, sociodemographics and exposure to chemicals was collected through a survey questionnaire, laboratory investigations and medical records. Descriptive results were reported as frequencies and proportions, adjusted odds ratios with 95 % confidence intervals and population attributable risk (PAR) as percentage.

Results

Among study participants (n = 428), AA was significantly associated with various environmental exposures. Participants residing in rural settings (OR = 2.29, 95 % CI 1.12–4.67, p-value < 0.01) and those who reported exposure to pesticides (OR = 3.58, 95 % CI 1.27–10.10, p-value 0.01; PAR = 18.16 %) were significantly more likely to report AA. Participants with a formal education were significantly less likely to have AA (OR = 0.27, 95 % CI 0.10–0.71, p-value < 0.01).

Conclusions

This study observed a significant association of aplastic anemia with a lower socioeconomic profile, and certain environmental exposures among the Pakistani population. The evidence may be helpful in understanding the pathophysiology of aplastic anemia in the context of environmental exposures.

Gibbilimbol analogues as antiparasitic agents--Synthesis and biological activity against Trypanosoma cruzi and Leishmania (L.) infantum

The essential oils from leaves of Piper malacophyllum (Piperaceae) showed to be mainly composed by two alkenylphenol derivatives: gibbilimbols A and B. After isolation and structural characterization by NMR and MS data analysis, both compounds were evaluated against promastigote/amastigote forms of Leishmania (L.) infantum as well as trypomastigote/amastigote forms of Trypanosoma cruzi. The obtained results indicated that gibbilimbol B displayed potential against the tested parasites and low toxicity to mammalian cells, stimulating the preparation of several quite simple synthetic analogues in order to improve its activity and to explore the preliminary structure-activity relationships (SAR) data. Among the prepared derivatives, compound LINS03003 (n-octyl-4-hydroxybenzylamine) displayed the most potent IC50 values of 5.5 and 1.8 μM against amastigotes of T. cruzi and L. (L.) infantum, respectively, indicating higher activity than the natural prototype. In addition, this compound showed remarkable selectivity index (SI) towards the intracellular forms of Leishmania (SI=13.1) and T. cruzi (SI=4.3). Therefore, this work indicated that preparation of synthetic compounds structurally based in the bioactive natural products could be an interesting source of novel and selective compounds against these protozoan parasites.

The consequences of human actions on risks for infectious diseases: a review

The human population is growing, requiring more space for food production, and needing more animals to feed it. Emerging infectious diseases are increasing, causing losses in both human and animal lives, as well as large costs to society. Many factors are contributing to disease emergence, including climate change, globalization and urbanization, and most of these factors are to some extent caused by humans. Pathogens may be more or less prone to emergence in themselves, and rapidly mutating viruses are more common among the emerging pathogens. The climate-sensitive vector-borne diseases are likely to be emerging due to climate changes and environmental changes, such as increased irrigation. This review lists the factors within pathogens that make them prone to emergence, and the modes of transmission that are affected. The anthropogenic changes contributing to disease emergence are described, as well as how they directly and indirectly cause either increased numbers of susceptible or exposed individuals, or cause increased infectivity. Many actions may have multiple direct or indirect effects, and it may be difficult to assess what the consequences may be. In addition, most anthropogenic drivers are related to desired activities, such as logging, irrigation, trade, and travelling, which the society is requiring. It is important to research more about the indirect and direct effects of the different actions to understand both the benefits and the risks.

Assessing the capacity to diagnose human African trypanosomiasis among health care personnel from Chama and Mambwe districts of eastern Zambia

Background

Human African Trypanosomiasis (HAT) is a neglected tropical disease affecting poor rural communities living in tsetse-infested regions of sub-Saharan Africa. In Zambia, sporadic cases of HAT have been reported mainly in the old foci along the tsetse-infested Luangwa river valley in north-eastern part of the country. In such places where malaria is the major endemic febrile disease, with possibilities of co-infections of HAT and malaria and where the levels of alertness to the presence of HAT among health care personnel (HCP) is low, there is a high chance of misdiagnosing HAT for malaria because of their similarities in clinical presentation. This study, conducted in Zambia’s tsetse-infested rural health centres (RHCs) of Chama and Mambwe districts, was designed to investigate the staffing levels, the HCP levels of alertness to the occurrence of HAT and their capacity to detect the disease.

Methods

Structured questionnaires were used to collect information pertaining to HAT alertness and the capacity to detect the disease from 101 HCP in a cross sectional study of 23 RHCs drawn from Zambia’s Chama and Mambwe districts between April and July 2013. The data collected were analyzed using Stata/SE version 11.0.

Results

Participants from both Chama and Mambwe district RHCs reported similar very low levels of qualified HCP and laboratory technicians, and that they had similar basic tools for HAT diagnosis. Although not statistically significant, respondents from Chama (~89 %) tended to be more aware about the occurrence of HAT compared to their Mambwe counterparts (~78 %). Whereas ~40 % of the HCP from Chama district (n = 52) claimed to have encountered at least one case of HAT, only ~4 % of their Mambwe counterparts (n = 49) had similar experiences (P = 0.000).

Conclusion

Health care personnel in RHCs from Chama tended to be more alert to the occurrence of HAT than the HCP from Mambwe district. The extremely low levels of categorized HCP, general absence of functional laboratories, coupled with absence of national HAT surveillance and control programs, are among some of the serious challenges that Zambia’s Chama and Mambwe districts face to control/eliminate HAT.

The Potential Use of Natural and Structural Analogues of Antimicrobial Peptides in the Fight against Neglected Tropical Diseases

Recently, research into the development of new antimicrobial agents has been driven by the increase in resistance to traditional antibiotics and Emerging Infectious Diseases. Antimicrobial peptides (AMPs) are promising candidates as alternatives to current antibiotics in the treatment and prevention of microbial infections. AMPs are produced by all known living species, displaying direct antimicrobial killing activity and playing an important role in innate immunity. To date, more than 2000 AMPs have been discovered and many of these exhibit broad-spectrum antibacterial, antiviral and anti-parasitic activity. Neglected tropical diseases (NTDs) are caused by a variety of pathogens and are particularly wide-spread in low-income and developing regions of the world. Alternative, cost effective treatments are desperately needed to effectively battle these medically diverse diseases. AMPs have been shown to be effective against a variety of NTDs, including African trypanosomes, leishmaniosis and Chagas disease, trachoma and leprosy. In this review, the potential of selected AMPs to successfully treat a variety of NTD infections will be critically evaluated.

Antitrypanosomal Acetylene Fatty Acid Derivatives from the Seeds of Porcelia macrocarpa (Annonaceae)

Chagas’ disease is caused by a parasitic protozoan and affects the poorest population in the world, causing high mortality and morbidity. As a result of the toxicity and long duration of current treatments, the discovery of novel and more efficacious drugs is crucial. In this work, the hexane extract from seeds of Porcelia macrocarpa R.E. Fries (Annonaceae) displayed in vitro antitrypanosomal activity against trypomastigote forms of T. cruzi by the colorimetric MTT assay (IC₅₀ of 65.44 μg/mL). Using chromatographic fractionation over SiO₂, this extract afforded a fraction composed by one active compound (IC₅₀ of 10.70 µg/mL), which was chemically characterized as 12,14-octadecadiynoic acid (macrocarpic acid). Additionally, two new inactive acetylene compounds (α,α'-dimacro-carpoyl-β-oleylglycerol and α-macrocarpoyl-α'-oleylglycerol) were also isolated from the hexane extract. The complete characterization of the isolated compounds was performed by analysis of NMR and MS data as well as preparation of derivatives.

Structure-function analysis of apical membrane-associated molecules of the tegument of schistosome parasites of humans: prospects for identification of novel targets for parasite control

Neglected tropical diseases are a group of some 17 diseases that afflict poor and predominantly rural people in developing nations. One significant disease that contributes to substantial morbidity in endemic areas is schistosomiasis, caused by infection with one of five species of blood fluke belonging to the trematode genus Schistosoma. Although there is one drug available for treatment of affected individuals in clinics, or for mass administration in endemic regions, there is a need for new therapies. A prominent target organ of schistosomes, either for drug or vaccine development, is the peculiar epithelial syncytium that forms the body wall (tegument) of this parasite. This dynamic layer is maintained and organized by concerted activity of a range of proteins, among which are the abundant tegumentary annexins. In this review, we will outline advances in structure-function analyses of these annexins, as a means to understanding tegument cell biology in host-parasite interaction and their potential exploitation as targets for anti-schistosomiasis therapies.

Economic and financial evaluation of neglected tropical diseases

Economic and financing studies are particularly important for decision-making when resources are scarce or considerably limited. This is the case for neglected tropical diseases (NTDs). In fact, the definition of NTDs is an economic one. The shortage of resources for NTD control may be due in large part to the fact that the burden of NTDs and economic value of control measures have not been fully characterized. A number of economic study methodologies are available: cost of illness can quantify the extent, magnitude, and change of a problem; cost of intervention studies can outline the feasibility and guide the design of a policy or intervention; and cost-benefit, cost-effectiveness, and return-on-investment studies can determine the potential value of different interventions and policies. NTDs have unique characteristics that require special consideration in such analyses. Hence, approaches used for other diseases may need modifications to capture the full impact of NTDs. While the existing literature has made important findings, there is a need for substantially more work, as many NTDs and their associated interventions and policies require more evaluation. With increasing work in this area, NTDs may not be as 'neglected' in the future as they are now.

Health metrics for helminth infections

Health metrics based on health-adjusted life years have become standard units for comparing the disease burden and treatment benefits of individual health conditions. The Disability-Adjusted Life Year (DALY) and the Quality-Adjusted Life Year (QALY) are the most frequently used in cost-effect analyses in national and global health policy discussions for allocation of health care resources. While sometimes useful, both the DALY and QALY metrics have limitations in their ability to capture the full health impact of helminth infections and other 'neglected tropical diseases' (NTDs). Gaps in current knowledge of disease burden are identified, and interim approaches to disease burden assessment are discussed.

Schistosomiasis mass drug administration in the Philippines: lessons learnt and the global implications

Schistosomiasis was first reported in the Philippines in 1906. A variety of treatments have been deployed to cure infection and to control the disease in the long-term. We discuss the journey to combat the disease in the Philippines and the lessons learnt which have implications for schistosomiasis control globally.

Development assistance for neglected tropical diseases: progress since 2009

Neglected tropical diseases (NTDs) is an umbrella term for a diverse group of debilitating infections that represent the most common afflictions for 2.7 billion people living on less than US$2 per day. Major efforts have recently re-focused attention on NTDs, including structured advocacy by the Bill and Melinda Gates Foundation, technical and political support by WHO and large-scale drug donation programs by pharmaceutical companies. An analysis of the Official Development Assistance (ODA) for NTDs in 2009 showed that Development Assistance Committee members and multilateral donors had largely ignored funding NTD control projects. This study reviews the changes since 2009 and finds an increased engagement by pharmaceutical manufacturers through drug donation programs substantially increased by the 'London Declaration' in 2012, a focused effort of 77 public and private partners on control or elimination of the 10 most common NTDs, but no increase in ODA for NTDs between 2008 and 2012. The allocation of ODA still does not reflect the respective importance of these diseases.

Cross-sectional study of the burden of vector-borne and soil-transmitted polyparasitism in rural communities of Coast Province, Kenya

Background

In coastal Kenya, infection of human populations by a variety of parasites often results in co-infection or poly-parasitism. These parasitic infections, separately and in conjunction, are a major cause of chronic clinical and sub-clinical human disease and exert a long-term toll on economic welfare of affected populations. Risk factors for these infections are often shared and overlap in space, resulting in interrelated patterns of transmission that need to be considered at different spatial scales. Integration of novel quantitative tools and qualitative approaches is needed to analyze transmission dynamics and design effective interventions.

Methodology

Our study was focused on detecting spatial and demographic patterns of single- and co-infection in six villages in coastal Kenya. Individual and household level data were acquired using cross-sectional, socio-economic, and entomological surveys. Generalized additive models (GAMs and GAMMs) were applied to determine risk factors for infection and co-infections. Spatial analysis techniques were used to detect local clusters of single and multiple infections.

Principal findings

Of the 5,713 tested individuals, more than 50% were infected with at least one parasite and nearly 20% showed co-infections. Infections with Schistosoma haematobium (26.0%) and hookworm (21.4%) were most common, as was co-infection by both (6.3%). Single and co-infections shared similar environmental and socio-demographic risk factors. The prevalence of single and multiple infections was heterogeneous among and within communities. Clusters of single and co-infections were detected in each village, often spatially overlapped, and were associated with lower SES and household crowding.

Conclusion

Parasitic infections and co-infections are widespread in coastal Kenya, and their distributions are heterogeneous across landscapes, but inter-related. We highlighted how shared risk factors are associated with high prevalence of single infections and can result in spatial clustering of co-infections. Spatial heterogeneity and synergistic risk factors for polyparasitism need to be considered when designing surveillance and intervention strategies.

In Coast Province, Kenya, infections with Schistosoma haematobium, Plasmodium spp., filarial nematodes, and geohelminths are common, resulting in high levels of both single infections and polyparasitism. The long-term effect of these infections, separately or in combination, has a major impact on human health and on the economic welfare of affected populations. The transmission dynamics of these parasitic infections can be linked to shared risk factors that often overlap in space. We studied human and environmental factors driving transmission and the resulting spatial pattern of infections in six communities, using cross-sectional, socio-economic and entomological surveys. Single and co-infections were widespread in the communities, and were associated with environmental, demographic and socio-economic risk factors, including distance of community from the coast, sanitation and human age and crowding. The spatial patterns of single and co-infections were heterogeneous among and within communities, with overlapping clusters of single and multiple infections in areas where houses with lower socio-economic status and more crowding were located. The heterogeneities among and within communities can provide important insights when designing surveillance and intervention strategies when planning appropriate surveillance and control strategies targeting polyparasitism.

Incidence of ventricular arrhythmias after stem cell therapy in patients with Chagas cardiomyopathy

Background

Treatment with stem cells in several cardiomyopathies may be related to the increase in arrhythmias.

Objectives

To determine whether intracoronary injection of stem cells in patients with Chagas cardiomyopathy is associated with increased incidence of ventricular arrhythmias, compared to the Control Group.

Methods

A retrospective cohort study that evaluated the medical records of 60 patients who participated in a previous cross-sectional study. The following data were collected: age, gender, drugs used and Holter variables that demonstrated the presence of arrhythmias. Holter was performed in four stages: randomization, 2, 6 and 12 months segments. The Control Group received medical treatment and intracoronary injection of placebo and the Study Group had drug treatment and autologous stem cell implant.

Results

There was no difference between Control Group and Study Group when analyzing the arrhythmia criteria. In the intra-group analysis, significant difference was found between the Holter tests of the Study Group for the variable total ventricular premature beats when compared with baseline, with p = 0.014 between Holter at randomization and Holter at 2 months, p = 0.004 between Holter at randomization and Holter at 6 months, and p = 0.014 between Holter at randomization and Holter at 12 months. The variable non-sustained ventricular tachycardia between Holter at randomization and Holter at 6 months showed p = 0.036.

Conclusion

The intracoronary injection of stem cells did not increase the incidence of ventricular arrhythmias in patients with Chagas cardiomyopathy compared to the Control Group.

Incorporating scale dependence in disease burden estimates: the case of human African trypanosomiasis in Uganda

BACKGROUND

The WHO has established the disability-adjusted life year (DALY) as a metric for measuring the burden of human disease and injury globally. However, most DALY estimates have been calculated as national totals. We mapped spatial variation in the burden of human African trypanosomiasis (HAT) in Uganda for the years 2000-2009. This represents the first geographically delimited estimation of HAT disease burden at the sub-country scale.

METHODOLOGY/PRINCIPAL FINDINGS

Disability-adjusted life-year (DALY) totals for HAT were estimated based on modelled age and mortality distributions, mapped using Geographic Information Systems (GIS) software, and summarised by parish and district. While the national total burden of HAT is low relative to other conditions, high-impact districts in Uganda had DALY rates comparable to the national burden rates for major infectious diseases. The calculated average national DALY rate for 2000-2009 was 486.3 DALYs/100 000 persons/year, whereas three districts afflicted by rhodesiense HAT in southeastern Uganda had burden rates above 5000 DALYs/100 000 persons/year, comparable to national GBD 2004 average burden rates for malaria and HIV/AIDS.

CONCLUSIONS/SIGNIFICANCE

These results provide updated and improved estimates of HAT burden across Uganda, taking into account sensitivity to under-reporting. Our results highlight the critical importance of spatial scale in disease burden analyses. National aggregations of disease burden have resulted in an implied bias against highly focal diseases for which geographically targeted interventions may be feasible and cost-effective. This has significant implications for the use of DALY estimates to prioritize disease interventions and inform cost-benefit analyses.