Socioeconomic aspects of neglected tropical diseases

Economic Evaluations of Mass Drug Administration: The Importance of Economies of Scale and Scope

It is recognized that changing the current approaches for the control of the neglected tropical diseases will be needed to reach the World Health Organization’s (WHO) 2020 goals. Consequently, it is important that economic evaluations of the alternative approaches are conducted. A vital component of such evaluations is the issue of how the intervention’s costs should be incorporated. We discuss this issue—focusing on mass drug administration. We argue that the common approach of assuming an intervention’s cost per treatment is constant, regardless of the number of individuals treated, is a misleading way to consider the delivery costs of mass drug administration due to the occurrence of economies/diseconomies of scale and scope. Greater care and consideration are required when the costs are incorporated into such analyses. Without this, these economic evaluations could potentially lead to incorrect policy recommendations.

Epidemiological findings and policy implications from the nationwide schistosomiasis and intestinal helminthiasis survey in Sudan

BACKGROUND

The World Health Assembly endorsed the WHO Neglected Tropical Disease (NTD) Roadmap in 2013, in which NTDs were suggested as tracers of equity in the assessment of progress towards the Sustainable Development Goals. Nationwide surveys were undertaken in all 18 states of Sudan to identify the geographical distribution and to estimate the prevalence and intensity of schistosomiasis and other intestinal helminthiases from December 2016 to March 2017.

METHODS

We used two-stage random sampling. Each district was subdivided into one to three different ecological zones (EZs) based on proximity to water bodies. Probability-proportional-to-size sampling was used to select schools from each EZ. We estimated schistosomiasis and intestinal helminthiasis prevalence by the centrifugation method and Kato-Katz smears. Multi-level mixed-effect models were used to investigate the relationship between the prevalence of infections and risk factors, including improved water or latrine status at the household or school level. We estimated the cost-effectiveness of a one-time mass drug administration (MDA) intervention with 75% coverage at the district and EZ levels.

RESULTS

A total of 105,167 students from 1772 schools were surveyed. The overall egg-positive rates were: Schistosoma haematobium, 5.2%; S. mansoni, 0.06%; and intestinal helminths, 5.47%. Severe endemic areas were concentrated in East and South Darfur States. Children living in a house or attending schools with an improved latrine were less likely to be infected with schistosomiasis than those without a latrine (adjusted odds ratio, aOR: 0.45, 95% confidence interval, CI: 0.41-0.51 and aOR: 0.75, 95% CI: 0.70-0.81 at the household or the school levels, respectively). Open defecation was strongly associated with schistosomiasis (aOR: 1.50, 95% CI: 1.35-1.66). In community-wide mass treatment at the district level with an 8% threshold for schistosomiasis, 2.2 million people would not benefit from MDA interventions with 75% coverage despite high endemicity, whilst 1.7 million people would receive the MDA intervention unnecessarily. EZ-level MDA was estimated to be more cost-effective than district-level administration under all circumstances.

CONCLUSIONS

Our findings provide updated prevalence figures to guide preventive chemotherapy programmes for schistosomiasis and intestinal helminthiasis in Sudan. Schistosomiasis was found to be common among the inhabitants of fragile and conflict-affected areas. In addition, we found that MDA interventions would be more cost-effective at the sub-district level than at the district level, and there was a strong association between schistosomiasis prevalence and latrine status, at both the household and school levels. This study will help the Sudanese government and its neighbouring countries develop adequate control and elimination strategies.

Economic evaluations of onchocerciasis interventions: a systematic review and research needs

OBJECTIVE

To provide a systematic review of economic evaluations that has been conducted for onchocerciasis interventions, to summarise current key knowledge and to identify research gaps.

METHOD

A systematic review of the literature was conducted on the 8th of August 2018 using the PubMed (MEDLINE) and ISI Web of Science electronic databases. No date or language stipulations were applied to the searches.

RESULTS

We identified 14 primary studies reporting the results of economic evaluations of onchocerciasis interventions, seven of which were cost-effectiveness analyses. The studies identified used a variety of different approaches to estimate the costs of the investigated interventions/programmes. Originally, the studies only quantified the benefits associated with preventing blindness. Gradually, methods improved and also captured onchocerciasis-associated skin disease. Studies found that eliminating onchocerciasis would generate billions in economic benefits. The majority of the cost-effectiveness analyses evaluated annual mass drug administration (MDA). The estimated cost per disability-adjusted life year (DALY) averted of annual MDA varies between US$3 and US$30 (cost year variable).

CONCLUSIONS

The cost benefit and cost effectiveness of onchocerciasis interventions have consistently been found to be very favourable. This finding provides strong evidential support for the ongoing efforts to eliminate onchocerciasis from endemic areas. Although these results are very promising, there are several important research gaps that need to be addressed as we move towards the 2020 milestones and beyond.

Current and promising novel drug candidates against visceral leishmaniasis

Leishmaniasis is a group of zoonotic diseases caused by a trypanosomatid parasite mostly in impoverished populations of low-income countries. In their different forms, leishmaniasis is prevalent in more than 98 countries all over the world and approximately 360-million people are at risk. Since no vaccine is currently available to prevent any form of the disease, the control strategy of leishmaniasis mainly relies on early case detection followed by adequate pharmacological treatment that may improve the prognosis and can reduce transmission. A handful of compounds and formulations are available for the treatment of leishmaniasis in humans, but only few of them are currently in use since most of these agents are associated with toxicity problems such as nephrotoxicity and cardiotoxicity in addition to resistance problems. In recent decades, very few novel drugs, new formulations of standard drugs or combinations of them have been approved against leishmaniasis. This review highlights the current drugs and combinations that are used medical practice and recent advances in new treatments against leishmaniasis that were pointed out in the recent 2nd Conference, Global Challenges in Neglected Tropical Diseases, held in San Juan, Puerto Rico in June 2018, emphasizing the plethora of new families of molecules that are bridging the gap between preclinical and first-in-man trials in next future.

Evaluation of emodepside in laboratory models of human intestinal nematode and schistosome infections

Background

Helminthiases are very prevalent worldwide, yet their treatment and control rely on a handful of drugs. Emodepside, a marketed broad-spectrum veterinary anthelminthic with a unique mechanism of action, undergoing development for onchocerciasis is an interesting anthelmintic drug candidate. We tested the in vitro and in vivo activity of emodepside on nematode species that serve as models for human soil-transmitted helminth infection as well as on schistosomes.

Methods

In vitro viability assays were performed over a time course of 72 hours for Trichuris muris, Necator americanus, Ancylostoma ceylanicum, Heligmosomoides polygyrus, Strongyloides ratti, Schistosoma mansoni and Schistosoma haematobium. The drug effect was determined by the survival rate for the larvae and by phenotypical scores for the adult worms. Additionally, mice infected with T. muris and hamsters harboring hookworm infection (N. americanus or A. ceylanicum) were administered orally with emodepside at doses ranging from 1.25 to 75 mg/kg. Expelled worms in the feces were counted until 3 days post-drug intake and worms residing in the intestines were collected and counted after dissection.

Results

After 24 hours, emodepside was very active in vitro against both larval and adult stages of the nematodes T. muris, A. ceylanicum, N. americanus, H. polygyrus and S. ratti (IC₅₀ < 4 µM). The good in vitro activity was confirmed in vivo. Hamsters infected with the hookworms were cured when administered orally with 2.5 mg/kg of the drug. Emodepside was also highly active in vivo against T. muris (ED₅₀ = 1.2 mg/kg). Emodepside was moderately active on schistosomula in vitro (IC₅₀ < 8 µM) 24 h post-drug incubation and its activity on adult S. mansoni and S. haematobium was low (IC₅₀: 30–50 µM).

Conclusions

Emodepside is highly active against a broad range of nematode species both in vitro and in vivo. The development of emodepside for treating soil-transmitted helminth infections should be pursued.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3476-x) contains supplementary material, which is available to authorized users.

Albendazole alone or in combination with microfilaricidal drugs for lymphatic filariasis

BACKGROUND

The Global Programme to Eliminate Lymphatic Filariasis recommends mass treatment of albendazole co-administered with the microfilaricidal (antifilarial) drugs diethylcarbamazine (DEC) or ivermectin; and recommends albendazole alone in areas where loiasis is endemic.

OBJECTIVES

To assess the effects of albendazole alone, and the effects of adding albendazole to DEC or ivermectin, in people and communities with lymphatic filariasis.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), Embase (OVID), LILACS (BIREME), and reference lists of included trials. We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform and ClinicalTrials.gov to identify ongoing trials. We performed all searches up to 15 January 2018.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and cluster-RCTs that compared albendazole to placebo or no placebo, or compared albendazole combined with a microfilaricidal drug to a microfilaricidal drug alone, given to people known to have lymphatic filariasis or communities where lymphatic filariasis was known to be endemic. We sought data on measures of transmission potential (microfilariae (mf) prevalence and density); markers of adult worm infection (antigenaemia prevalence and density, and adult worm prevalence detected by ultrasound); and data on clinical disease and adverse events.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed the trials, evaluated the risks of bias, and extracted data. The main analysis examined albendazole overall, whether given alone or added to a microfilaricidal drug. We used data collected from all randomized individuals at time of longest follow-up (up to 12 months) for meta-analysis of outcomes. We evaluated mf density data up to six months and at 12 months follow-up to ensure that we did not miss any subtle temporal effects. We conducted additional analyses for different follow-up periods and whether trials reported on individuals known to be infected or both infected and uninfected. We analysed dichotomous data using the risk ratio (RR) with a 95% confidence interval (CI). We could not meta-analyse data on parasite density outcomes and we summarized them in tables. Where data were missing, we contacted trial authors. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 13 trials (12 individually-randomized and one small cluster-randomized trial) with 8713 participants in total. No trials evaluated population-level effects of albendazole in mass drug administration programmes. Seven trials enrolled people with a variety of inclusion criteria related to filarial infection, and six trials enrolled individuals from endemic areas. Outcomes were reported as end or change values. Mf and antigen density data were reported using the geometric mean, log mean and arithmetic mean, and reductions in density were variously calculated. Two trials discounted any increases in mf density in individuals at follow-up by setting any density increase to zero.For mf prevalence over two weeks to 12 months, albendazole alone or added to another microfilaricidal drug makes little or no difference (RR 0.95, 95% CI 0.85 to 1.07; 5027 participants, 12 trials, high-certainty evidence). For mf density there is no trend, with some trials reporting a greater reduction in mf density with albendazole and others a greater reduction with the control group. For mf density up to six months and at 12 months, we do not know if albendazole has an effect (one to six months: 1216 participants, 10 trials, very low-certainty evidence; at 12 months: 1052 participants, 9 trials, very low-certainty evidence).For antigenaemia prevalence between six to 12 months, albendazole alone or added to another microfilaricidal drug makes little or no difference (RR 1.04, 95% CI 0.97 to 1.12; 3774 participants, 7 trials, high-certainty evidence). For antigen density over six to 12 months, the trend shows little or no effect of albendazole; but we do not know if albendazole has an effect on antigen density (1374 participants, 5 trials, very low-certainty evidence). For adult worm prevalence detected by ultrasound at 12 months, albendazole added to a microfilaricidal drug may make little or no difference (RR 1.16, 95% CI 0.72 to 1.86; 165 participants, 3 trials, low-certainty evidence).For people reporting adverse events, albendazole makes little or no difference (RR 0.97, 95% CI 0.84 to 1.13; 2894 participants, 6 trials, high-certainty evidence).We also provide meta-analyses and GRADE tables by drug, as operationally this may be of interest: for albendazole versus placebo (4 trials, 1870 participants); for albendazole with DEC compared to DEC alone (8 trials, 3405 participants); and albendazole with ivermectin compared to ivermectin alone (4 trials, 3438 participants).

AUTHORS' CONCLUSIONS

There is good evidence that albendazole makes little difference to clearing microfilaraemia or adult filarial worms in the 12 months post-treatment. This finding is consistent in trials evaluating albendazole alone, or added to DEC or ivermectin. Trials reporting mf density included small numbers of participants, calculated density data variously, and gave inconsistent results.The review raises questions over whether albendazole has any important contribution to the elimination of lymphatic filariasis. To inform policy for areas with loiasis where only albendazole can be used, it may be worth conducting placebo-controlled trials of albendazole alone.

Mitochondrial disfunction and ROS production are essential for anti-Trypanosoma cruzi activity of β-lapachone-derived naphthoimidazoles

Chagas disease is caused by the hemoflagellate protozoa Trypanosoma cruzi and is one of the most important neglected tropical diseases, especially in Latin American countries, where there is an association between low-income populations and mortality. The nitroderivatives used in current chemotherapy are far from ideal and present severe limitations, justifying the continuous search for alternative drugs. Since the1990s, our group has been investigating the trypanocidal activity of natural naphthoquinones and their derivatives, and three naphthoimidazoles (N1, N2 and N3) derived from β-lapachone were found to be most effective in vitro. Analysis of their mechanism of action via cellular, molecular and proteomic approaches indicates that the parasite mitochondrion contains one of the primary targets of these compounds, trypanothione synthetase (involved in trypanothione production), which is overexpressed after treatment with these compounds. Here, we further evaluated the participation of the mitochondria and reactive oxygen species (ROS) in the anti-T. cruzi action of naphthoimidazoles. Preincubation of epimastigotes and trypomastigotes with antioxidants (α-tocopherol and urate) strongly protected the parasites from the trypanocidal effect of naphthoimidazoles, decreasing the ROS levels produced and reverting the mitochondrial swelling phenotype. The addition of pro-oxidants (menadione and H₂O₂) before the treatment induced an increase in parasite lysis. Despite the O₂ uptake and mitochondrial complex activity being strongly reduced by N1, N2 and N3, urate partially restored the mitochondrial metabolism only in N1-treated parasites. In parallel, MitoTEMPO, a mitochondrial-targeted antioxidant, protected the functionality of the mitochondria in N2- and N3-treated parasites. In addition, the trypanothione reductase activity was remarkably increased after treatment with N1 and N3, and molecular docking demonstrated that these two compounds were positioned in pockets of this enzyme. Based on our findings, the direct impairment of the mitochondrial electron transport chain by N2 and N3 led to an oxidative misbalance, which exacerbated ROS generation and led to parasite death. Although other mechanisms cannot be discounted, mainly in N1-treated parasites, further investigations are required.

Health, financial, and education gains of investing in preventive chemotherapy for schistosomiasis, soil-transmitted helminthiases, and lymphatic filariasis in Madagascar: A modeling study

BACKGROUND

Neglected tropical diseases (NTDs) account for a large disease burden in sub-Saharan Africa. While the general cost-effectiveness of NTD interventions to improve health outcomes has been assessed, few studies have also accounted for the financial and education gains of investing in NTD control.

METHODS

We built on extended cost-effectiveness analysis (ECEA) methods to assess the health gains (e.g. infections, disability-adjusted life years or DALYs averted), household financial gains (out-of-pocket expenditures averted), and education gains (cases of school absenteeism averted) for five NTD interventions that the government of Madagascar aims to roll out nationally. The five NTDs considered were schistosomiasis, lymphatic filariasis, and three soil-transmitted helminthiases (Ascaris lumbricoides, Trichuris trichiura, and hookworm infections).

RESULTS

The estimated incremental cost-effectiveness for the roll-out of preventive chemotherapy for all NTDs jointly was USD125 per DALY averted (95% uncertainty range: 65-231), and its benefit-cost ratio could vary between 5 and 31. Our analysis estimated that, per dollar spent, schistosomiasis preventive chemotherapy, in particular, could avert a large number of infections (176,000 infections averted per $100,000 spent), DALYs (2,000 averted per $100,000 spent), and cases of school absenteeism (27,000 school years gained per $100,000 spent).

CONCLUSION

This analysis incorporates financial and education gains into the economic evaluation of health interventions, and therefore provides information about the efficiency of attainment of three Sustainable Development Goals (SDGs). Our findings reveal how the national scale-up of NTD control in Madagascar can help address health (SDG3), economic (SDG1), and education (SDG4) goals. This study further highlights the potentially large societal benefits of investing in NTD control in low-resource settings.

TrypanocidalActivity of Natural Sesquiterpenoids Involves Mitochondrial Dysfunction, ROS Production and Autophagic Phenotype in Trypanosomacruzi

Chagas disease is a neglected tropical disease that is caused by the protozoan Trypanosoma cruzi and represents a serious health problem, especially in Latin America. The clinical treatment of Chagas disease is based on two nitroderivatives that present severe side effects and important limitations. In folk medicine, natural products, including sesquiterpenoids, have been employed for the treatment of different parasitic diseases. In this study, the trypanocidal activity of compounds isolated from the Chilean plants Drimys winteri, Podanthus mitiqui and Maytenus boaria on three T. cruzi evolutive forms (epimastigote, trypomastigote and amastigote) was evaluated. Total extracts and seven isolated sesquiterpenoids were assayed on trypomastigotes and epimastigotes. Polygodial (Pgd) from D. winteri, total extract from P. mitiqui (PmTE) and the germacrane erioflorin (Efr) from P. mitiqui were the most bioactive substances. Pgd, Efr and PmTE also presented strong effects on intracellular amastigotes and low host toxicity. Many ultrastructural effects of these substances, including reservosome disruption, cytosolic vacuolization, autophagic phenotype and mitochondrial swelling (in the case of Pgd), were observed. Flow cytometric analysis demonstrated a reduction in mitochondrial membrane potential in treated epimastigotes and an increase in ROS production and high plasma membrane permeability after treatment with Pgd. The promising trypanocidal activity of these natural sesquiterpenoids may be a good starting point for the development of alternative treatmentsforChagas disease.

Challenges and recent progress in drug discovery for tropical diseases

Infectious tropical diseases have a huge effect in terms of mortality and morbidity, and impose a heavy economic burden on affected countries. These diseases predominantly affect the world's poorest people. Currently available drugs are inadequate for the majority of these diseases, and there is an urgent need for new treatments. This Review discusses some of the challenges involved in developing new drugs to treat these diseases and highlights recent progress. While there have been notable successes, there is still a long way to go.

Equity and efficiency in the scaled-up implementation of integrated neglected tropical disease control: the health economics protocol of the COUNTDOWN multicountry observational study in Ghana, Cameroon and Liberia

INTRODUCTION

Worldwide, millions of individuals are affected by neglected tropical diseases (NTDs). They are frequently the poorest and most marginalised members of society. Their living conditions, among other things, make them susceptible to such diseases. Historically, several large-scale treatment programmes providing mass drug administrations (MDAs) were carried out per single disease but over the last decade there has been an increasing trend towards co-implementation of MDA activities given the resources used for such programmes are often the same. The COUNTDOWN multicountry studies focus on scaled-up implementation of integrated control strategies against four diseases: lymphatic filariasis, onchocerciasis, schistosomiasis and soil-transmitted helminthiasis. The objective of the COUNTDOWN economic study is to assess the multicountry implementation of control interventions in terms of equity, impact and efficiency.

METHODS

The health economic study uses different analytical methods to assess the relationship between NTDs and poverty and the cost-effectiveness of different large-scale intervention options. Regression analysis will be used to study the determinants of NTD occurrence, the impact of NTDs on poverty, factors that hinder access to MDAs and the effect of NTDs on quality-of-life of those affected, including disability. Cost-effectiveness analyses of various integration methods will be performed using health economic modelling to estimate the cost and programme impact of different integration options. Here, cost-effectiveness ratios will be calculated, including multivariate sensitivity analyses, using Bayesian analysis.

ETHICS AND DISSEMINATION

Ethics approval has been received both at the Liverpool School of Tropical Medicine and in all participating countries. Results of the various substudies will be presented for publication in peer-reviewed journals.

STUDY DATES

1 July 2016 to 30 June-October 2019.

Innovation in neglected tropical disease drug discovery and development

BACKGROUND

Neglected tropical diseases (NTDs) are closely related to poverty and affect over a billion people in developing countries. The unmet treatment needs cause high mortality and disability thereby imposing a huge burden with severe social and economic consequences. Although coordinated by the World Health Organization, various philanthropic organizations, national governments and the pharmaceutical industry have been making efforts in improving the situation, the control of NTDs is still inadequate and extremely difficult today. The lack of safe, effective and affordable medicines is a key contributing factor. This paper reviews the recent advances and some of the challenges that we are facing in the fight against NTDs.

MAIN BODY

In recent years, a number of innovations have demonstrated propensity to promote drug discovery and development for NTDs. Implementation of multilateral collaborations leads to continued efforts and plays a crucial role in drug discovery. Proactive approaches and advanced technologies are urgently needed in drug innovation for NTDs. However, the control and elimination of NTDs remain a formidable task as it requires persistent international cooperation to make sustainable progresses for a long period of time. Some currently employed strategies were proposed and verified to be successful, which involve both mechanisms of 'Push' which aims at cutting the cost of research and development for industry and 'Pull' which aims at increasing market attractiveness. Coupled to this effort should be the exercise of shared responsibility globally to reduce risks, overcome obstacles and maximize benefits. Since NTDs are closely associated with poverty, it is absolutely essential that the stakeholders take concerted and long-term measures to meet multifaceted challenges by alleviating extreme poverty, strengthening social intervention, adapting climate changes, providing effective monitoring and ensuring timely delivery.

CONCLUSIONS

The ongoing endeavor at the global scale will ultimately benefit the patients, the countries they are living and, hopefully, the manufacturers who provide new preventive, diagnostic and therapeutic products.

Purinergic receptors and neglected tropical diseases: why ignore purinergic signaling in the search for new molecular targets?

Purinergic receptors are widespread in the human organism and are involved in several physiological functions like neurotransmission, nociception, platelet aggregation, etc. In the immune system, they may regulate the expression and release of pro-inflammatory factors as well as the activation and death of several cell types. It is already described the participation of some purinergic receptors in the inflammation and pathological processes, such as a few neglected tropical diseases (NTDs) which affect more than 1 billion people in the world. Although the high social influence those diseases represent endemic countries, most of them do not have an efficient, safe or affordable drug treatment. In that way, this review aims to discuss the current literature involving purinergic receptor and immune response to NTDs pathogens, which may contribute in the search for new therapeutic possibilities.

Outcome of E1224-Benznidazole Combination Treatment for Infection with a Multidrug-Resistant Trypanosoma cruzi Strain in Mice

Combination therapy has been proposed as an alternative therapeutic approach for the treatment of Chagas disease. In this study, we evaluated the effect of treatment with benznidazole combined with E1224 (ravuconazole prodrug) in an experimental murine model of acute infection. The first set of experiments assessed the range of E1224 doses required to induce parasitological cure using Trypanosoma cruzi strains with different susceptibilities to benznidazole (Y and Colombian). All E1224 doses were effective in suppressing the parasitemia and preventing death; however, parasitological cure was observed only in mice infected with Y strain. Considering these results, we evaluated the effect of combined treatment against Colombian, a multidrug-resistant T. cruzi strain. After exclusion of antagonistic effects using in vitro assays, infected mice were treated with E1224 and benznidazole in monotherapy or in combination at day 4 or 10 postinoculation. All treatments were well tolerated and effective in suppressing parasitemia; however, parasitological and PCR assays indicated no cure among mice treated with monotherapies. Intriguingly, the outcome of combination therapy was dependent on treatment onset. Early treatment using optimal doses of E1224-benznidazole induced a 100% cure rate, but this association could not eliminate a well-established infection. The beneficial effect of combination therapy was evidenced by further reductions of the patent parasitemia period in the group receiving combined therapy compared with monotherapies. Our results demonstrated a positive interaction between E1224 and benznidazole against murine T. cruzi infection using a multidrug-resistant strain and highlighted the importance of a stringent experimental model in the evaluation of new therapies.

Screening a repurposing library, the Medicines for Malaria Venture Stasis Box, against Schistosoma mansoni

Background

The development of new treatments against schistosomiasis is imperative but lacks commercial interest. Drug repurposing represents a suitable strategy to identify potential treatments, which have already unblocked several essential steps along the drug development path, hence reducing costs and timelines. Promoting this approach, the Medicines for Malaria Venture (MMV) recently distributed a drug repurposing library of 400 advanced lead candidates (Stasis Box).

Methods

All 400 compounds were initially tested in vitro against the larval stage of Schistosoma mansoni at 10 μM. Hits progressed to screening on adult worms and were further characterised for IC_50, cytotoxicity and selectivity. Ten lead compounds were tested in mice harbouring a chronic S. mansoni infection.

Results

Eleven of the 37 compounds active on the larval stage were also highly active on adult worms in vitro (IC₅₀ = 2.0–7.5 μM). IC₅₀ values on adult S. mansoni decreased substantially in the presence of albumin (7.5–123.5 μM). Toxicity to L6 and MRC cells was moderate. A moderate worm burden reduction of 51.6% was observed for MMV690534, while the other 9 compounds showed low activity. None of the in vivo results were statistically significant (P > 0.05).

Conclusions

Phenotypic screening of advanced lead compounds is a simple and resource-low method to identify novel anthelminthics. None of the promising hits of the Stasis Box identified in vitro against S. mansoni yielded acceptable worm burden reductions in vivo, which might be due to the high plasma protein binding. Since the in vitro hits interfere with different drug targets, they might provide a starting point for target based screening and structure-activity relationship studies.

Climate Change and the Neglected Tropical Diseases

Climate change is expected to impact across every domain of society, including health. The majority of the world's population is susceptible to pathological, infectious disease whose life cycles are sensitive to environmental factors across different physical phases including air, water and soil. Nearly all so-called neglected tropical diseases (NTDs) fall into this category, meaning that future geographic patterns of transmission of dozens of infections are likely to be affected by climate change over the short (seasonal), medium (annual) and long (decadal) term. This review offers an introduction into the terms and processes deployed in modelling climate change and reviews the state of the art in terms of research into how climate change may affect future transmission of NTDs. The 34 infections included in this chapter are drawn from the WHO NTD list and the WHO blueprint list of priority diseases. For the majority of infections, some evidence is available of which environmental factors contribute to the population biology of parasites, vectors and zoonotic hosts. There is a general paucity of published research on the potential effects of decadal climate change, with some exceptions, mainly in vector-borne diseases.

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.

Chagas disease

Chagas disease is an anthropozoonosis from the American continent that has spread from its original boundaries through migration. It is caused by the protozoan Trypanosoma cruzi, which was identified in the first decade of the 20th century. Once acute infection resolves, patients can develop chronic disease, which in up to 30-40% of cases is characterised by cardiomyopathy, arrhythmias, megaviscera, and, more rarely, polyneuropathy and stroke. Even after more than a century, many challenges remain unresolved, since epidemiological control and diagnostic, therapeutic, and prognostic methods must be improved. In particular, the efficacy and tolerability profile of therapeutic agents is far from ideal. Furthermore, the population affected is older and more complex (eg, immunosuppressed patients and patients with cancer). Nevertheless, in recent years, our knowledge of Chagas disease has expanded, and the international networking needed to change the course of this deadly disease during the 21st century has begun.

Quality of anthelminthic medicines available in Jimma Ethiopia

Soil-transmitted helminthiasis and schistosomiasis are major public health problems in Ethiopia. Mass deworming of at-risk population using a single dose administration of 400mg albendazole (ABZ) or 500mg mebendazole (MBZ) for treatment of common intestinal worms and 40mg of praziquantel (PZQ) per kg body weight for treatment of schistosomiasis is one of the strategies recommended by World Health Organization (WHO) in order to control the morbidity of soil-transmitted helminthiasis and schistosomiasis. Since storage condition, climate, way of transportation and distribution route could all affect the quality of medicines, regular assessment by surveys is very critical to ensure the therapeutic outcome, to minimize risk of toxicity to the patient and resistance of parasites. Therefore, this study was conducted to assess the pharmaceutical quality of ABZ, MBZ and PZQ tablet brands commonly available in Jimma town (south west Ethiopia). Retail pharmacies (n=10) operating in Jimma town were selected using simple random sampling method. Samples of anthelminthic medicines available in the selected pharmacies were collected. Sample information was recorded and encompassed trade name, active ingredient name, manufacturer's name and full address, labeled medicine strength, dosage form, number of units per container, dosage statement, batch/lot number, manufacturing and expiry dates, storage information and presence of leaflets/package insert. Moreover, a first visual inspection was performed encompassing uniformity of color, uniformity of size, breaks, cracks, splits, embedded surface spots or visual contaminations. Finally, physico-chemical quality attributes investigated encompassed mass uniformity, quantity of active pharmaceutical ingredient (API), disintegration and dissolution, all following Pharmacopoeial test methods The physical characteristics of dosage form, packaging and labeling information of all samples complied with criteria given in the WHO checklists. The mass uniformity of tablets of each brand of ABZ, MBZ and PZQ complied with the pharmacopoeial specification limits, i.e no more than 2 individual masses >5% of average tablet weight, and none deviate by more than 10%. The quantity of APIs in all investigated tablet brands were within the 90-110% label claim (l.c.) limits, ranging between 95.05 and 110.09% l.c. Disintegration times were in line with the pharmacopoeial specification limit for immediate release (IR) tablets, ranging between 0.5 and 13min. However, the dissolution results (mean±SD, n=6) of one ABZ brand (i.e. Wormin^®, Q=59.21±0.99% at 30min) and two PZQ brands (i.e. Bermoxel^®, Q=63.43%±0.7 and Distocide^®, Q=62.43%±1.67, at 75min) showed poor dissolution, failing the United States Pharmacopoeia (USP) dissolution specification limit.

Ruthenium-catalyzed C–H oxygenation of quinones by weak O-coordination for potent trypanocidal agents

C–H oxygenation of quinones by weak O-coordination was achieved by versatile ruthenium(ii) catalysis with ample substrate scope and trypanocidal compounds were also identified.

Investment Success in Public Health: An Analysis of the Cost-Effectiveness and Cost-Benefit of the Global Programme to Eliminate Lymphatic Filariasis

Background.

It has been estimated that $154 million per year will be required during 2015–2020 to continue the Global Programme to Eliminate Lymphatic Filariasis (GPELF). In light of this, it is important to understand the program’s current value. Here, we evaluate the cost-effectiveness and cost-benefit of the preventive chemotherapy that was provided under the GPELF between 2000 and 2014. In addition, we also investigate the potential cost-effectiveness of hydrocele surgery.

Methods.

Our economic evaluation of preventive chemotherapy was based on previously published health and economic impact estimates (between 2000 and 2014). The delivery costs of treatment were estimated using a model developed by the World Health Organization. We also developed a model to investigate the number of disability-adjusted life years (DALYs) averted by a hydrocelectomy and identified the cost threshold under which it would be considered cost-effective.

Results.

The projected cost-effectiveness and cost-benefit of preventive chemotherapy were very promising, and this was robust over a wide range of costs and assumptions. When the economic value of the donated drugs was not included, the GPELF would be classed as highly cost-effective. We projected that a typical hydrocelectomy would be classed as highly cost-effective if the surgery cost less than $66 and cost-effective if less than $398 (based on the World Bank’s cost-effectiveness thresholds for low income countries).

Conclusions.

Both the preventive chemotherapy and hydrocele surgeries provided under the GPELF are incredibly cost-effective and offer a very good investment in public health.

The monetary value of human lives lost due to neglected tropical diseases in Africa

BACKGROUND

Neglected tropical diseases (NTDs) are an important cause of death and disability in Africa. This study estimates the monetary value of human lives lost due to NTDs in the continent in 2015.

METHODS

The lost output or human capital approach was used to evaluate the years of life lost due to premature deaths from NTDs among 10 high/upper-middle-income (Group 1), 17 middle-income (Group 2) and 27 low-income (Group 3) countries in Africa. The future losses were discounted to their present values at a 3% discount rate. The model was re-analysed using 5% and 10% discount rates to assess the impact on the estimated total value of human lives lost.

RESULTS

The estimated value of 67 860 human lives lost in 2015 due to NTDs was Int$ 5 112 472 607. Out of that, 14.6% was borne by Group 1, 57.7% by Group 2 and 27.7% by Group 3 countries. The mean value of human life lost per NTD death was Int$ 231 278, Int$ 109 771 and Int$ 37 489 for Group 1, Group 2 and Group 3 countries, respectively. The estimated value of human lives lost in 2015 due to NTDs was equivalent to 0.1% of the cumulative gross domestic product of the 53 continental African countries.

CONCLUSIONS

Even though NTDs are not a major cause of death, they impact negatively on the productivity of those affected throughout their life-course. Thus, the case for investing in NTDs control should also be influenced by the value of NTD morbidity, availability of effective donated medicines, human rights arguments, and need to achieve the NTD-related target 3.3 of the United Nations Sustainable Development Goal 3 (on health) by 2030.

The cost of mapping trachoma: Data from the Global Trachoma Mapping Project

Background

The Global Trachoma Mapping Project (GTMP) was implemented with the aim of completing the baseline map of trachoma globally. Over 2.6 million people were examined in 1,546 districts across 29 countries between December 2012 and January 2016. The aim of the analysis was to estimate the unit cost and to identify the key cost drivers of trachoma prevalence surveys conducted as part of GTMP.

Methodology and principal findings

In-country and global support costs were obtained using GTMP financial records. In-country expenditure was analysed for 1,164 districts across 17 countries. The mean survey cost was $13,113 per district [median: $11,675; IQR = $8,365-$14,618], $17,566 per evaluation unit [median: $15,839; IQR = $10,773-$19,915], $692 per cluster [median: $625; IQR = $452-$847] and $6.0 per person screened [median: $4.9; IQR = $3.7-$7.9]. Survey unit costs varied substantially across settings, and were driven by parameters such as geographic location, demographic characteristics, seasonal effects, and local operational constraints. Analysis by activities showed that fieldwork constituted the largest share of in-country survey costs (74%), followed by training of survey teams (11%). The main drivers of in-country survey costs were personnel (49%) and transportation (44%). Global support expenditure for all surveyed districts amounted to $5.1m, which included grant management, epidemiological support, and data stewardship.

Conclusion

This study provides the most extensive analysis of the cost of conducting trachoma prevalence surveys to date. The findings can aid planning and budgeting for future trachoma surveys required to measure the impact of trachoma elimination activities. Furthermore, the results of this study can also be used as a cost basis for other disease mapping programmes, where disease or context-specific survey cost data are not available.

There are currently few data sets available to aid programmes in planning and budgeting for population-based surveys in low- and middle- income countries. With the objective of identifying cost drivers and key variables influencing prevalence survey costs, the authors collected expenses incurred during the Global Trachoma Mapping Project (GTMP) which surveyed 2.6 million people across 29 countries. Expenditure from surveying 1,164 districts in 17 countries was analysed. Our results showed that the majority of in-country expenditure was spent on personnel (per diems, accommodation, meals and beverages) (49%) and local transportation (44%) and that the median survey expenditure was US$11,675 per district (or US$15,839 per evaluation unit, US$625 per cluster and US$4.9 per person examined). There were large variations in survey unit costs across settings, based on local geographic, demographic, seasonal effects and local operational characteristics. In addition, the resources required for the global support and coordination of the GTMP were analysed and amounted to US$5.1m (US$3,318 per district or US$5,668 per EU). Global support expenses can be substantial for a large multi-country mapping exercise conducted in a limited period of time such as the GTMP. Findings from this study can be used to inform other disease mapping projects, and to inform planning and budgeting for the prevalence surveys that will assess the impact of trachoma elimination interventions.

Estimating the economic and social consequences for patients diagnosed with human African trypanosomiasis in Muchinga, Lusaka and Eastern Provinces of Zambia (2004-2014)

BACKGROUND

Acute human African trypanosomiasis (rHAT) caused by Trypanosoma brucei rhodesiense is associated with high mortality and is fatal if left untreated. Only a few studies have examined the psychological, social and economic impacts of rHAT. In this study, mixed qualitative and quantitative research methods were used to evaluate the socio-economic impacts of rHAT in Mambwe, Rufunsa, Mpika and Chama Districts of Zambia.

METHODS

Individuals diagnosed with rHAT from 2004 to 2014 were traced using hospital records and discussions with communities. Either they, or their families, were interviewed using a structured questionnaire and focus group discussions were conducted with affected communities. The burden of the disease was investigated using disability adjusted life years (DALYs), with and without discounting and age-weighting. The impact of long-term disabilities on the rHAT burden was also investigated.

RESULTS

Sixty four cases were identified in the study. The majority were identified in second stage, and the mortality rate was high (12.5%). The total number of DALYs was 285 without discounting or age-weighting. When long-term disabilities were included this estimate increased by 50% to 462. The proportion of years lived with disability (YLD) increased from 6.4% to 37% of the undiscounted and un-age-weighted DALY total. When a more active surveillance method was applied in 2013-2014 the cases identified increased dramatically, suggesting a high level of under-reporting. Similarly, the proportion of females increased substantially, indicating that passive surveillance may be especially failing this group. An average of 4.9 months of productive time was lost per patient as a consequence of infection. The health consequences included pain, amnesia and physical disability. The social consequences included stigma, dropping out of education, loss of friends and self-esteem. Results obtained from focus group discussions revealed misconceptions among community members which could be attributed to lack of knowledge about rHAT.

CONCLUSIONS

The social and economic impact of rHAT on rural households and communities is substantial. Improved surveillance and strengthening of local medical services are needed for early and accurate diagnosis. Disease prevention should be prioritised in communities at risk of rHAT, and interventions put in place to prevent zoonotic disease spill over from domestic animals and wildlife. Supportive measures to mitigate the long-term effects of disability due to rHAT are needed.

Climate Change Contribution to the Emergence or Re-Emergence of Parasitic Diseases

The connection between our environment and parasitic diseases may not always be straightforward, but it exists nonetheless. This article highlights how climate as a component of our environment, or more specifically climate change, has the capability to drive parasitic disease incidence and prevalence worldwide. There are both direct and indirect implications of climate change on the scope and distribution of parasitic organisms and their associated vectors and host species. We aim to encompass a large body of literature to demonstrate how a changing climate will perpetuate, or perhaps exacerbate, public health issues and economic stagnation due to parasitic diseases. The diseases examined include those caused by ingested protozoa and soil helminths, malaria, lymphatic filariasis, Chagas disease, human African trypanosomiasis, leishmaniasis, babesiosis, schistosomiasis, and echinococcus, as well as parasites affecting livestock. It is our goal to impress on the scientific community the magnitude a changing climate can have on public health in relation to parasitic disease burden. Once impending climate changes are now upon us, and as we see these events unfold, it is critical to create management plans that will protect the health and quality of life of the people living in the communities that will be significantly affected.

Disease burden of hepatitis E in a rural population in China: a community-based survey

This study aimed to estimate the disease burden of hepatitis E in a rural region in China. A total of 489 hepatitis E cases were reported according to a community-based survey in an active hepatitis surveillance system between 2008 and 2015, the questionnaire and record-review methods were constructed to evaluate the economic and health burden of hepatitis E virus infections from societal perspectives. All costs were converted to US$ in 2015. The age-standardized cumulative incidence rate was 107·9/100 000, and the median age-standardized annual incidence rate was 16·5/100 000. The median direct, indirect, and intangible cost were $1046·0, $49·1, and $77·3/patient, respectively, and the median economic burden per patient was $1836·5, which accounted for 51·2% of per capita disposable income. Moreover, the median quality-adjusted life year and visual analogue scale score were 0·7 and 70·0/case, respectively. Both economic burden and health burden of inpatients was more serious than that of outpatients (P < 0·001). Disease burden of hepatitis E is heavy on patients, their families, and society. More studies on the disease burden of hepatitis E are necessary to increase social awareness of the disease and confirm reasonable disease-control measures.

A systematic review of factors that shape implementation of mass drug administration for lymphatic filariasis in sub-Saharan Africa

BACKGROUND

Understanding factors surrounding the implementation process of mass drug administration for lymphatic filariasis (MDA for LF) elimination programmes is critical for successful implementation of similar interventions. The sub-Saharan Africa (SSA) region records the second highest prevalence of the disease and subsequently several countries have initiated and implemented MDA for LF. Systematic reviews have largely focused on factors that affect coverage and compliance, with less attention on the implementation of MDA for LF activities. This review therefore seeks to document facilitators and barriers to implementation of MDA for LF in sub-Saharan Africa.

METHODS

A systematic search of databases PubMed, Science Direct and Google Scholar was conducted. English peer-reviewed publications focusing on implementation of MDA for LF from 2000 to 2016 were considered for analysis. Using thematic analysis, we synthesized the final 18 articles to identify key facilitators and barriers to MDA for LF programme implementation.

RESULTS

The main factors facilitating implementation of MDA for LF programmes were awareness creation through innovative community health education programmes, creation of partnerships and collaborations, integration with existing programmes, creation of morbidity management programmes, motivation of community drug distributors (CDDs) through incentives and training, and management of adverse effects. Barriers to implementation included the lack of geographical demarcations and unregistered migrations into rapidly urbanizing areas, major disease outbreaks like the Ebola virus disease in West Africa, delayed drug deliveries at both country and community levels, inappropriate drug delivery strategies, limited number of drug distributors and the large number of households allocated for drug distribution.

CONCLUSION

Mass drug administration for lymphatic filariasis elimination programmes should design their implementation strategies differently based on specific contextual factors to improve implementation outcomes. Successfully achieving this requires undertaking formative research on the possible constraining and inhibiting factors, and incorporating the findings in the design and implementation of MDA for LF.

The cross-cutting contribution of the end of neglected tropical diseases to the sustainable development goals

The Sustainable Development Goals (SDGs) call for an integrated response, the kind that has defined Neglected Tropical Diseases (NTDs) efforts in the past decade.NTD interventions have the greatest relevance for SDG3, the health goal, where the focus on equity, and its commitment to reaching people in need of health services, wherever they may live and whatever their circumstances, is fundamentally aligned with the target of Universal Health Coverage. NTD interventions, however, also affect and are affected by many of the other development areas covered under the 2030 Agenda. Strategies such as mass drug administration or the programmatic integration of NTD and WASH activities (SDG6) are driven by effective global partnerships (SDG17). Intervention against the NTDs can also have an impact on poverty (SDG1) and hunger (SDG2), can improve education (SDG4), work and economic growth (SDG8), thereby reducing inequalities (SDG10). The community-led distribution of donated medicines to more than 1 billion people reinforces women's empowerment (SDG5), logistics infrastructure (SDG9) and non-discrimination against disability (SDG16). Interventions to curb mosquito-borne NTDs contribute to the goals of urban sustainability (SDG11) and resilience to climate change (SDG13), while the safe use of insecticides supports the goal of sustainable ecosystems (SDG15). Although indirectly, interventions to control water- and animal-related NTDs can facilitate the goals of small-scale fishing (SDG14) and sustainable hydroelectricity and biofuels (SDG7).NTDs proliferate in less developed areas in countries across the income spectrum, areas where large numbers of people have little or no access to adequate health care, clean water, sanitation, housing, education, transport and information. This scoping review assesses how in this context, ending the epidemic of the NTDs can impact and improve our prospects of attaining the SDGs.

Challenges in the chemotherapy of Chagas disease: Looking for possibilities related to the differences and similarities between the parasite and host

Almost 110 years after the first studies by Dr. Carlos Chagas describing an infectious disease that was named for him, Chagas disease remains a neglected illness and a death sentence for infected people in poor countries. This short review highlights the enormous need for new studies aimed at the development of novel and more specific drugs to treat chagasic patients. The primary tool for facing this challenge is deep knowledge about the similarities and differences between the parasite and its human host.

Neglected tropical diseases: progress towards addressing the chronic pandemic

The concept of neglected tropical diseases (NTDs) emerged more than a decade ago and has been recognised as a valid way to categorise diseases that affect the poorest individuals. Substantial progress in control and elimination has been achieved and policy momentum has been generated through continued bilateral, philanthropic, and non-governmental development organisation (NGDO) support, and donations of drugs from pharmaceutical companies. WHO has defined a Roadmap to reach 2020 targets, which was endorsed by member states in a World Health Assembly Resolution in 2013. NTDs have been included within the Sustainable Development Goal targets and are a crucial component of universal health coverage, conceptualised as "leaving no one behind". WHO reported that more than 1 billion people in 88 countries have benefited from preventive chemotherapy in 2014. The research agenda has defined the need for affordable products (diagnostics, drugs and insecticides). However challenges such as insecurity and weak health systems continue to prevail in the poorest countries, inhibiting progress in scaling up and also in achieving Roadmap goals.

Increasing European Support for Neglected Infectious Disease Research

Neglected infectious diseases (NIDs) are a persistent cause of death and disability in low-income countries. Currently available drugs and vaccines are often ineffective, costly or associated with severe side-effects. Although the scale of research on NIDs does not reflect their disease burden, there are encouraging signs that NIDs have begun to attract more political and public attention, which have translated into greater awareness and increased investments in NID research by both public and private donors. Using publicly available data, we analysed funding for NID research in the European Union's (EU's) 7th Framework Programme for Research and Technological Development (FP7), which ran from 2007 to 2013. During FP7, the EU provided €169 million for 65 NID research projects, and thereby placed itself among the top global funders of NID research. Average annual FP7 investment in NID research exceeded €24 million, triple that committed by the EU before the launch of FP7. FP7 NID projects involved research teams from 331 different institutions in 72 countries on six continents, underlining the increasingly global nature of European research activities. NID research has remained a priority in the current EU Framework Programme for research and innovation, Horizon 2020, launched in 2014. This has most notably been reflected in the second programme of the European & Developing Countries Clinical Trials Partnership (EDCTP), which provides unprecedented opportunities to advance the clinical development of new medical interventions against NIDs. Europe is thus better positioned than ever before to play a major role in the global fight against NIDs.

Pterodon emarginatus oleoresin-based nanoemulsion as a promising tool for Culex quinquefasciatus (Diptera: Culicidae) control

BACKGROUND

Preparation of nanoformulations using natural products as bioactive substances is considered very promising for innovative larvicidal agents. On this context, oil in water nanoemulsions develop a main role, since they satisfactorily disperse poor-water soluble substances, such as herbal oils, in aqueous media. Pterodon emarginatus, popularly known as sucupira, has a promising bioactive oleoresin. However, to our knowledge, no previous studies were carried out to evaluate its potential against Culex quinquefasciatus, the main vector of the tropical neglected disease called lymphatic filariasis or elephantiasis. Thus, we aimed to investigate influence of different pairs of surfactants in nanoemulsion formation and investigate if a sucupira oleoresin-based nanoemulsion has promising larvicidal activity against this C. quinquefasciatus. We also evaluated morphological alteration, possible mechanism of insecticidal action and ecotoxicity of the nanoemulsion against a non-target organism.

RESULTS

Among the different pairs of surfactants that were tested, nanoemulsions obtained with polysorbate 80/sorbitan monooleate and polysorbate 80/sorbitan trioleate presented smallest mean droplet size just afterwards preparation, respectively 151.0 ± 2.252 and 160.7 ± 1.493 nm. They presented high negative zeta potential values, low polydispersity index (<0.300) and did not present great alteration in mean droplet size and polydispersity index after 1 day of preparation. Overall, nanoemulsion prepared with polysorbate 80/sorbitan monooleate was considered more stable and was chosen for biological assays. It presented low LC50 value against larvae (34.75; 7.31-51.86 mg/L) after 48 h of treatment and some morphological alteration was observed. The nanoemulsion did not inhibit acetylcholinesterase of C. quinquefasciatus larvae. It was not toxic to green algae Chlorella vulgaris at low concentration (25 mg/L).

CONCLUSIONS

Our results suggest that optimal nanoemulsions may be prepared with different surfactants using a low cost and low energy simple method. Moreover, this prototype proved to be effective against C. quinquefasciatus, being considered an ecofriendly novel nanoproduct that can be useful in integrated control programs of vector control.

In vitro antimicrobial and in vivo wound healing effect of actinobacterially synthesised nanoparticles of silver, gold and their alloy

Antibacterial, antifungal and wound healing potential of actinobacterially synthesised Ag, Au and Ag/Au nanoparticles.

The Socioeconomic Benefit to Individuals of Achieving the 2020 Targets for Five Preventive Chemotherapy Neglected Tropical Diseases

BACKGROUND

Lymphatic filariasis (LF), onchocerciasis, schistosomiasis, soil-transmitted helminths (STH) and trachoma represent the five most prevalent neglected tropical diseases (NTDs). They can be controlled or eliminated by means of safe and cost-effective interventions delivered through programs of Mass Drug Administration (MDA)-also named Preventive Chemotherapy (PCT). The WHO defined targets for NTD control/elimination by 2020, reinforced by the 2012 London Declaration, which, if achieved, would result in dramatic health gains. We estimated the potential economic benefit of achieving these targets, focusing specifically on productivity and out-of-pocket payments.

METHODS

Productivity loss was calculated by combining disease frequency with productivity loss from the disease, from the perspective of affected individuals. Productivity gain was calculated by deducting the total loss expected in the target achievement scenario from the loss in a counterfactual scenario where it was assumed the pre-intervention situation in 1990 regarding NTDs would continue unabated until 2030. Economic benefits from out-of-pocket payments (OPPs) were calculated similarly. Benefits are reported in 2005 US$ (purchasing power parity-adjusted and discounted at 3% per annum from 2010). Sensitivity analyses were used to assess the influence of changes in input parameters.

RESULTS

The economic benefit from productivity gain was estimated to be I$251 billion in 2011-2020 and I$313 billion in 2021-2030, considerably greater than the total OPPs averted of I$0.72 billion and I$0.96 billion in the same periods. The net benefit is expected to be US$ 27.4 and US$ 42.8 for every dollar invested during the same periods. Impact varies between NTDs and regions, since it is determined by disease prevalence and extent of disease-related productivity loss.

CONCLUSION

Achieving the PCT-NTD targets for 2020 will yield significant economic benefits to affected individuals. Despite large uncertainty, these benefits far exceed the investment required by governments and their development partners within all reasonable scenarios. Given the concentration of the NTDs among the poorest households, these investments represent good value for money in efforts to share the world's prosperity and reduce inequity.

Interactions between 4-aminoquinoline and heme: Promising mechanism against Trypanosoma cruzi

Chagas disease is a neglected tropical disease caused by the flagellated protozoan Trypanosoma cruzi. The current drugs used to treat this disease have limited efficacy and produce severe side effects. Quinolines, nitrogen heterocycle compounds that form complexes with heme, have a broad spectrum of antiprotozoal activity and are a promising class of new compounds for Chagas disease chemotherapy. In this study, we evaluated the activity of a series of 4-arylaminoquinoline-3-carbonitrile derivatives against all forms of Trypanosoma cruzi in vitro. Compound 1g showed promising activity against epimastigote forms when combined with hemin (IC50<1 μM), with better performance than benznidazole, the reference drug. This compound also inhibited the viability of trypomastigotes and intracellular amastigotes. The potency of 1g in combination with heme was enhanced against epimastigotes and trypomastigotes, suggesting a similar mechanism of action that occurs in Plasmodium spp. The addition of hemin to the culture medium increased trypanocidal activity of analog 1g without changing the cytotoxicity of the host cell, reaching an IC50 of 11.7 μM for trypomastigotes. The mechanism of action was demonstrated by the interaction of compound 1g with hemin in solution and prevention of heme peroxidation. Compound 1g and heme treatment induced alterations of the mitochondrion-kinetoplast complex in epimastigotes and trypomastigotes and also, accumulation of electron-dense deposits in amastigotes as visualized by transmission electron microscopy. The trypanocidal activity of 4-aminoquinolines and the elucidation of the mechanism involving interaction with heme is a neglected field of research, given the parasite's lack of heme biosynthetic pathway and the importance of this cofactor for parasite survival and growth. The results of this study can improve and guide rational drug development and combination treatment strategies.

The impact of an 8-year mass drug administration programme on prevalence, intensity and co-infections of soil-transmitted helminthiases in Burundi

Background

Soil-transmitted helminth (STH) infections are amongst the most prevalent infections in the world. Mass drug administration (MDA) programmes have become the most commonly used national interventions for endemic countries to achieve elimination. This paper aims to describe the effect of an 8-year MDA programme on the prevalence, intensity of infection and co-infection of STH in Burundi from 2007 to 2014 and critically appraise the trajectory towards STH elimination in the country.

Results

Annual STH parasitological surveys (specifically, a “pilot study” from 2007 to 2011, an “extension study” from 2008 to 2011, and a “national reassessment” in 2014; n = 27,658 children), showed a significant drop in prevalence of infection with any STH (“pooled STH”) between baseline and 2011 in both studies, falling from 32 to 16 % in the pilot study, and from 35 to 16 % in the extension study. Most STH infections were of low intensity according to WHO classification. The national reassessment in 2014 showed that prevalence of pooled STH remained significantly below the prevalence in 2007 in both studies but there was no further decrease in STH prevalence from 2011 levels during this time. Spatial dependence analysis showed that prevalence of Trichuris trichiura and Ascaris lumbricoides had a tendency to cluster over the years, whilst only trends in spatial dependence were evident for hookworm infections. Spatial dependence fluctuated over the course of the programme for Ascaris lumbricoides and Trichuris trichiura. However, spatial trends in spatial dependence were evident in 2010 for Ascaris lumbricoides. Analysis of spatial clustering of intensity of infection and heavy infections revealed that the intensity changed over time for all parasites. Heavy intensity was only evident in Ascaris lumbricoides for 2008 and did not appear in proceeding years and other parasites.

Conclusions

These results demonstrate that sustained annual MDA significantly reduced the prevalence of STH infection in school-age children but was unable to achieve elimination. Additionally, significant decline in prevalence was accompanied by a drop in spatial clustering of infection indicators across all sites from 2008. The lack of consistency in the results of the spatial dependence analysis highlights that MDA programmes can interrupt the normal transmission dynamics of STH parasites.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1794-9) contains supplementary material, which is available to authorized users.

Circumvention of Learning Increases Intoxication Efficacy of Nematicidal Engineered Bacteria

Synthetic biology holds promise to engineer systems to treat diseases. One critical, yet underexplored, facet of designing such systems is the interplay between the system and the pathogen. Understanding this interplay may be critical to increasing efficacy and overcoming resistance against the system. Using the principles of synthetic biology, we engineer a strain of Escherichia coli to attract and intoxicate the nematode Caenorhabditis elegans. Our bacteria are engineered with a toxin module, which intoxicates the nematode upon ingestion, and an attraction module, which serves to attract and increase the feeding rate of the nematodes. When independently implemented, these modules successfully intoxicate and attract the worms, respectively. However, in combination, the efficacy of our bacteria is significantly reduced due to aversive associative learning in C. elegans. Guided by mathematical modeling, we dynamically regulate module induction to increase intoxication by circumventing learning. Our results detail the creation of a novel nematicidal bacterium that may have application against nematodes, unravel unique constraints on circuit dynamics that are governed by C. elegans physiology, and add to the growing list of design and implementation considerations associated with synthetic biology.

Parasitic diseases of the central nervous system: lessons for clinicians and policy makers

Parasitic diseases of the central nervous system are associated with high mortality and morbidity, especially in resource-limited settings. The burden of these diseases is amplified as survivors are often left with neurologic sequelae affecting mobility, sensory organs, and cognitive functions, as well as seizures/epilepsy. These diseases inflict suffering by causing lifelong disabilities, reducing economic productivity, and causing social stigma. The complexity of parasitic life cycles and geographic specificities, as well as overlapping clinical manifestations in the host reflecting the diverse pathogenesis of parasites, can present diagnostic challenges. We herein provide an overview of these parasitic diseases and summarize clinical aspects, diagnosis, therapeutic strategies and recent milestones, and aspects related to prevention and control.

Concerted Efforts to Control or Eliminate Neglected Tropical Diseases: How Much Health Will Be Gained?

Background

The London Declaration (2012) was formulated to support and focus the control and elimination of ten neglected tropical diseases (NTDs), with targets for 2020 as formulated by the WHO Roadmap. Five NTDs (lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminths and trachoma) are to be controlled by preventive chemotherapy (PCT), and four (Chagas’ disease, human African trypanosomiasis, leprosy and visceral leishmaniasis) by innovative and intensified disease management (IDM). Guinea worm, virtually eradicated, is not considered here. We aim to estimate the global health impact of meeting these targets in terms of averted morbidity, mortality, and disability adjusted life years (DALYs).

Methods

The Global Burden of Disease (GBD) 2010 study provides prevalence and burden estimates for all nine NTDs in 1990 and 2010, by country, age and sex, which were taken as the basis for our calculations. Estimates for other years were obtained by interpolating between 1990 (or the start-year of large-scale control efforts) and 2010, and further extrapolating until 2030, such that the 2020 targets were met. The NTD disease manifestations considered in the GBD study were analyzed as either reversible or irreversible. Health impacts were assessed by comparing the results of achieving the targets with the counterfactual, construed as the health burden had the 1990 (or 2010 if higher) situation continued unabated.

Principle Findings/Conclusions

Our calculations show that meeting the targets will lead to about 600 million averted DALYs in the period 2011–2030, nearly equally distributed between PCT and IDM-NTDs, with the health gain amongst PCT-NTDs mostly (96%) due to averted disability and amongst IDM-NTDs largely (95%) from averted mortality. These health gains include about 150 million averted irreversible disease manifestations (e.g. blindness) and 5 million averted deaths. Control of soil-transmitted helminths accounts for one third of all averted DALYs. We conclude that the projected health impact of the London Declaration justifies the required efforts.

Neglected tropical diseases (NTDs) are a group of infectious diseases that occur mostly in poor, warm countries. NTDs are caused by various bacteria and parasites, such as worms. They can either be cured or prevented through drugs and other interventions, such as control of insects that spread the infection. The London Declaration is a statement by various organizations, including the World Health Organization (WHO) and pharmaceutical companies that donate the necessary drugs. The declaration endorses targets for disease reductions by 2020, as recently formulated in the WHO Roadmap, to be achieved by rigorous application of available interventions. We explore how much health can be gained if these targets are indeed achieved. We estimate that in such case 5 million deaths can be averted before 2030 and also that huge reductions in ill-health and disability can be realized. Over the period 2011–2030, a total health gain would be accomplished of about 600 million disability adjusted life years (DALYs) averted. DALYs are a measure of disease burden, consisting of life years lost and years lived with disability. This enormous health gain seems to justify similar investments as for e.g. HIV or malaria control.

Application of GIS technology in public health: successes and challenges

The uptake and acceptance of Geographic Information Systems (GIS) technology has increased since the early 1990s and public health applications are rapidly expanding. In this paper, we summarize the common uses of GIS technology in the public health sector, emphasizing applications related to mapping and understanding of parasitic diseases. We also present some of the success stories, and discuss the challenges that still prevent a full scope application of GIS technology in the public health context. Geographical analysis has allowed researchers to interlink health, population and environmental data, thus enabling them to evaluate and quantify relationships between health-related variables and environmental risk factors at different geographical scales. The ability to access, share and utilize satellite and remote-sensing data has made possible even wider understanding of disease processes and of their links to the environment, an important consideration in the study of parasitic diseases. For example, disease prevention and control strategies resulting from investigations conducted in a GIS environment have been applied in many areas, particularly in Africa. However, there remain several challenges to a more widespread use of GIS technology, such as: limited access to GIS infrastructure, inadequate technical and analytical skills, and uneven data availability. Opportunities exist for international collaboration to address these limitations through knowledge sharing and governance.

Productivity Loss Related to Neglected Tropical Diseases Eligible for Preventive Chemotherapy: A Systematic Literature Review

BACKGROUND

Neglected Tropical Diseases (NTDs) not only cause health and life expectancy loss, but can also lead to economic consequences including reduced ability to work. This article describes a systematic literature review of the effect on the economic productivity of individuals affected by one of the five worldwide most prevalent NTDs: lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminths (ascariasis, trichuriasis, and hookworm infection) and trachoma. These diseases are eligible to preventive chemotherapy (PCT).

METHODOLOGY/PRINCIPAL FINDINGS

Eleven bibliographic databases were searched using different names of all NTDs and various keywords relating to productivity. Additional references were identified through reference lists from relevant papers. Of the 5316 unique publications found in the database searches, thirteen papers were identified for lymphatic filariasis, ten for onchocerciasis, eleven for schistosomiasis, six for soil-transmitted helminths and three for trachoma. Besides the scarcity in publications reporting the degree of productivity loss, this review revealed large variation in the estimated productivity loss related to these NTDs.

CONCLUSIONS

It is clear that productivity is affected by NTDs, although the actual impact depends on the type and severity of the NTD as well as on the context where the disease occurs. The largest impact on productivity loss of individuals affected by one of these diseases seems to be due to blindness from onchocerciasis and severe schistosomiasis manifestations; productivity loss due to trachoma-related blindness has never been studied directly. However, productivity loss at an individual level might differ from productivity loss at a population level because of differences in the prevalence of NTDs. Variation in estimated productivity loss between and within diseases is caused by differences in research methods and setting. Publications should provide enough information to enable readers to assess the quality and relevance of the study for their purposes.

Prevalence of Schistosomes and Soil-Transmitted Helminths and Morbidity Associated with Schistosomiasis among Adult Population in Lake Victoria Basin, Tanzania

The objective of this study was to carry out a community survey on schistosomiais and soil-transmitted helminth (STH) infections in order to suggest feasible and effective intervention strategies in Lake Victoria basin, Tanzania. A total of 37 communities selected from 23 districts of the 4 regions in the Lake Victoria basin of Tanzania were involved in the study. From each of the selected locality, 50 adult community members, 25 males and 25 females, were recruited for the study. Each study participant was requested to submit stool and urine specimens. From each stool specimen, duplicate Kato-Katz thick smears were prepared and microscopically examined for Schistosoma mansoni and STH eggs. Urine specimens were processed by the filtration technique and microscopically examined for Schistosoma haematobium eggs. Ultrasound examination for morbidity due to schistosomiasis was performed. Mass treatment was done using praziquantel and albendazole for schistosome and STHs infections, respectively. Out of 1,606 adults who provided stool specimens, 199 (12.4%) were positive for S. mansoni, 349 (21.7%) for hookworms, 133 (8.3%) for Ascaris lumbricoides, and 33 (2.0%) for Trichuris trichiura. Out of 1,400 participants who provided urine specimens, 25 (1.8%) were positive for S. haematobium eggs. Because of the co-endemicity of these afflictions and their impact on vulnerable population groups, the helminthiasis could be simultaneously treated with 2 drugs, praziquantel for schistosomiasis and albendazole for STHs.

Prevalence of Schistosomes and Soil-Transmitted Helminths among Schoolchildren in Lake Victoria Basin, Tanzania

The objectives of this study was to conduct a survey on schistosomiasis and soil-transmitted helminth (STH) infections in order to come up with feasible control strategies in Lake Victoria basin, Tanzania. Depending on the size of the school, 150-200 schoolchildren were recruited for the study. Duplicate Kato-Katz stool smears were prepared from each child and microscopically examined for Schistosoma mansoni and STHs. Urine specimens were examined for Schistosoma haematobium eggs using the filtration technique. After the survey, mass drug administration was done using praziquantel and albendazole for schistosomiasis and STHs infections, respectively. A total of 5,952 schoolchildren from 36 schools were recruited for the study and had their stool and urine specimens examined. Out of 5,952 schoolchildren, 898 (15.1%) were positive for S. mansoni, 754 (12.6%) for hookworms, 188 (3.2%) for Ascaris lumblicoides, and 5 (0.008%) for Trichuris trichiura. Out of 5,826 schoolchildren who provided urine samples, 519 (8.9%) were positive for S. haematobium eggs. The results revealed that intestinal schistosomiasis, urogenital schistosomiasis, and STH infections are highly prevalent throughought the lake basin. The high prevalence of intestinal and urogenital schistosomisiasis in the study area was a function of the distance from Lake Victoria, the former being more prevalent at localities close to the lake, whilst the latter is more so away from it. Control of schistosomiasis and STHs in the study area requires an integrated strategy that involves provision of health education to communities, regular treatments, and provision of adequate safe water supply and sanitation facilities.

Diagnosis of neglected tropical diseases among patients with persistent digestive disorders (diarrhoea and/or abdominal pain ≥14 days): Pierrea multi-country, prospective, non-experimental case-control study

Background

Diarrhoea still accounts for considerable mortality and morbidity worldwide. The highest burden is concentrated in tropical areas where populations lack access to clean water, adequate sanitation and hygiene. In contrast to acute diarrhoea (<14 days), the spectrum of pathogens that may give rise to persistent diarrhoea (≥14 days) and persistent abdominal pain is poorly understood. It is conceivable that pathogens causing neglected tropical diseases play a major role, but few studies investigated this issue. Clinical management and diagnostic work-up of persistent digestive disorders in the tropics therefore remain inadequate. Hence, important aspects regarding the pathogenesis, epidemiology, clinical symptomatology and treatment options for patients presenting with persistent diarrhoea and persistent abdominal pain should be investigated in multi-centric clinical studies.

Methods/Design

This multi-country, prospective, non-experimental case–control study will assess persistent diarrhoea (≥14 days; in individuals aged ≥1 year) and persistent abdominal pain (≥14 days; in children/adolescents aged 1–18 years) in up to 2000 symptomatic patients and 2000 matched controls. Subjects from Côte d’Ivoire, Indonesia, Mali and Nepal will be clinically examined and interviewed using a detailed case report form. Additionally, each participant will provide a stool sample that will be examined using a suite of diagnostic methods (i.e., microscopic techniques, rapid diagnostic tests, stool culture and polymerase chain reaction) for the presence of bacterial and parasitic pathogens. Treatment will be offered to all infected participants and the clinical treatment response will be recorded. Data obtained will be utilised to develop patient-centred clinical algorithms that will be validated in primary health care centres in the four study countries in subsequent studies.

Discussion

Our research will deepen the understanding of the importance of persistent diarrhoea and related digestive disorders in the tropics. A diversity of intestinal pathogens will be assessed for potential associations with persistent diarrhoea and persistent abdominal pain. Different diagnostic methods will be compared, clinical symptoms investigated and diagnosis-treatment algorithms developed for validation in selected primary health care centres. The findings from this study will improve differential diagnosis and evidence-based clinical management of digestive syndromes in the tropics.

Trial registration

ClinicalTrials.gov; identifier: NCT02105714.

Cost and cost-effectiveness of soil-transmitted helminth treatment programmes: systematic review and research needs

BACKGROUND

In this time of rapidly expanding mass drug administration (MDA) coverage and the new commitments for soil-transmitted helminth (STH) control, it is essential that resources are allocated in an efficient manner to have the greatest impact. However, many questions remain regarding how best to deliver STH treatment programmes; these include which age-groups should be targeted and how often. To perform further analyses to investigate what the most cost-effective control strategies are in different settings, accurate cost data for targeting different age groups at different treatment frequencies (in a range of settings) are essential.

METHODS

Using the electronic databases PubMed, MEDLINE, and ISI Web of Knowledge, we perform a systematic review of costing studies and cost-effectiveness evaluations for potential STH treatment strategies. We use this review to highlight research gaps and outline the key future research needs.

RESULTS

We identified 29 studies reporting costs of STH treatment and 17 studies that investigated its cost-effectiveness. The majority of these pertained to programmes only targeting school-aged children (SAC), with relatively few studies investigating alternative preventive chemotherapy (PCT) treatment strategies. The methods of cost data collection, analysis and reporting were highly variable among the different studies. Only four of the costing studies were found to have high applicability for use in forthcoming economic evaluations. There are also very few studies quantifying the costs of increasing the treatment frequency.

CONCLUSIONS

The absence of cost data and inconsistencies in the collection and analysis methods constitutes a major research gap for STH control. Detailed and accurate costs of targeting different age groups or increasing treatment frequency will be essential to formulate cost-effective public health policy. Defining the most cost-effective control strategies in different settings is of high significance during this period of expanding MDA coverage and new resource commitments for STH control.