Global burden on neglected tropical diseases

Pyrethroid resistance distribution in Triatoma infestans and environmental association along the Argentine endemic zone

Insecticide resistance is considered a barrier to chemical control of Triatoma infestans, the main vector of Chagas disease in the Southern Cone of South America. Although initiatives to reduce the incidence of the disease in the region have integrated different strategies, they have mainly relied on vector elimination using pyrethroid insecticides such as deltamethrin. Reports of pyrethroid resistance in connection with T. infestans control failures first emerged in northern Argentina and southern Bolivia. Recently, a mosaic pyrethroid-resistant focus has been described in the center of the Argentine Gran Chaco (Department of General Güemes, Chaco Province), characterized by the presence of susceptible and very highly resistant populations in the same area. The involvement of different resistance mechanisms has been proposed, together with the contribution of environmental variables that promote the toxicological heterogeneity described. In the endemic zone of Argentina, however, new questions arise: Are there any other clusters of resistance? Is there a relationship between the distribution of resistance and environmental variables (as has been observed at smaller scale)? We studied toxicological data from insects collected and analyzed at 224 localities between 2010 and 2020 as part of the resistance monitoring conducted by the Chagas National Program. The sites were classified according to the survival rate of insects exposed to a discriminant dose of deltamethrin: 0-0.19 were considered susceptible, 0.2-0.79 low-resistance, and 0.8-1 high-resistance. Localities were georeferenced to describe the spatial distribution of resistance and to identify environmental variables (demographics, land use, urbanization, connectivity, and climate) potentially associated with resistance. We used Generalized Linear Models (GLMs) to examine the association between resistance and environmental predictors, selecting error distributions based on the response variable definition. For the entire period, 197 susceptible localities were distributed across the endemic zone. Localities with different survival rates were found throughout the area; 9 high-resistance localities circled the two previously identified resistant foci, and 18 low-resistance in 6 provinces, highlighting their relevance for control planning. Precipitation variables were linked to resistance in all the GLMs evaluated. Presence/absence models were the most accurate, with precipitation, distance from the capital city, and land use contributing to the distribution of resistance. This information could be valuable for improving T. infestans control strategies in future scenarios characterized by unpredictable changes in land use and precipitation.

Factors associated with pediatric febrile illnesses in 27 countries of Sub-Saharan Africa

BACKGROUND

Evidence on the relative importance of various factors associated with febrile illness in children and their heterogeneity across countries can inform the prevention, identification, and management of communicable diseases in resource-limited countries. The objective of the study is to assess the relative significance of factors associated with childhood febrile illness in 27 sub-Saharan African countries.

METHODS

This cross-sectional study of 298,327 children aged 0 to 59 months assessed the strengths of associations of 18 factors with childhood fevers, using Demographic and Health Surveys (2010-2018) from 27 sub-Saharan African countries. A total of 7 child level factors (i.e., respiratory illness, diarrhea, breastfeeding initiation; vitamin A supplements; child's age; full vaccination; sex), 5 maternal factors (maternal education; maternal unemployment; antenatal care; maternal age, and maternal marriage status) and 6 household factors (household wealth; water source; indoor pollution, stool disposal; family planning needs and rural residence) were assessed. Febrile illness was defined as the presence of fever in 2 weeks preceding the survey.

RESULTS

Among the 298,327 children aged 0 to 59 months included in the analysis, the weighted prevalence of fever was 22.65% (95% CI, 22.31%-22.91%). In the pooled sample, respiratory illness was the strongest factor associated with fever in children (adjusted odds ratio [aOR], 5.46; 95% CI, 5.26-5.67; P < .0001), followed by diarrhea (aOR, 2.96; 95% CI, 2.85-3.08; P < .0001), poorest households (aOR, 1.33; 95% CI,1.23-1.44; P < .0001), lack of maternal education (aOR, 1.25; 95% CI, 1.10-1.41; P < .0001), and delayed breastfeeding (aOR, 1.18; 95% CI, 1.14-1.22; P < .0001. Febrile illnesses were more prevalent in children older than >6 months compared to those 6 months and younger. Unsafe water, unsafe stool disposal, and indoor pollution were not associated with child fever in the pooled analysis but had a large country-level heterogeneity.

CONCLUSIONS

Major causes of fevers in sub-Saharan Africa could be attributed to respiratory infections and possibly viral infections, which should not be treated by antimalarial drugs or antibiotics. Point-of-care diagnostics are needed to identify the pathogenic causes of respiratory infections to guide the clinical management of fevers in limited-resource countries.

Attendee's awareness about preventive chemotherapy neglected tropical diseases (PC-NTD) control during the first world neglected tropical diseases day in Ekiti State, Nigeria

BACKGROUND

The need to control Neglected Tropical Diseases (NTDs) and sustain progress towards elimination through mass administration of medicines requires substantial communal participation. This study, therefore, assessed the knowledge and perception of attendees' regarding NTDs and its control activities during the inaugural World NTD day event in Ekiti State, Nigeria.

METHODOLOGY

A cross-sectional study involving the administration of pretested semi-structured questionnaires to consenting attendees at the Inaugural World NTD day event was conducted on the 30th January, 2020. The questionnaire collected data on attendee's demography, knowledge and awareness about NTDs and its control in Nigeria. Quantitative data were analysed using descriptive statistics in SPSS. 20.0 software and expressed as frequencies and percentages. However, qualitative data to support quantitative analysis were obtained using open-ended questionnaires and analysed thematically.

PRINCIPAL FINDINGS/CONCLUSION

A total of 309 attendees comprising 167 (54.0%) females, and 142 (46.0%) males participated in this study. By age groupings, majority 206 (66.7%) were within 15-25 years. 167 (54.8%) of the attendees have not heard about NTDs before, whereas 77(35.0%) have heard about NTDs through the advertisement of the event. 181(63.3%) were aware of ongoing NTD control programs in schools and communities. Also, 246 (83.4%) of them have not taken or do not know anyone that has taken drugs donated in schools or communities. The number of attendees 41(13.3%) who incorrectly classified malaria as NTDs is higher than those who recognized onchocerciasis 36 (11.7%) and worm infections 34(11.0%) as NTDs (p>0.05). This study has shown that awareness and knowledge about NTDs control activities in Ekiti State is low, thus justifying the event as an awareness day for addressing NTDs. Public enlightment and regular promotional activities such as media engagement will raise the public appreciation and participation in NTDs control activities.

Prioritising pathogens for the management of severe febrile patients to improve clinical care in low- and middle-income countries

Background

Severe febrile illness without a known source (SFWS) is a challenge for clinicians when deciding how to manage a patient, particularly given the wide spectrum of potential aetiologies that contribute to fever. These infections are difficult to distinguish clinically, and accurate diagnosis requires a plethora of diagnostics including blood cultures, imaging techniques, molecular or serological tests, and more. When laboratory services are available, a limited test menu hinders clinical decision-making and antimicrobial stewardship, leading to empiric treatment and suboptimal patient outcomes. To specifically address SFWS, this work aimed to identify priority pathogens for a globally applicable panel for fever causing pathogens.

Method

A pragmatic two-pronged approach combining currently available scientific data in an analytical hierarchy process and systematically gathered expert input, was designed to address the lack of comprehensive global aetiology data. The expert re-ranked list was then further adapted for a specific use case to focus on community acquired infections in whole blood specimens. The resulting list was further analysed to address different geographical regions (Asia, Africa, and Latin America), and Cohen kappa scores of agreement were calculated.

Results

The expert ranked prioritized pathogen list generated as part of this two-pronged approach included typhoidal Salmonella, Plasmodium species and Mycobacterium tuberculosis as the top 3 pathogens. This pathogen list was then further adapted for the SFWS use case to develop a final pathogen list to inform product development. Subsequent analysis comparing the relevance of the SFWS pathogen list to multiple populations and geographical regions showed that the SFWS prioritized list had considerable utility across Africa and Asia, but less so for Latin America. In addition, the list showed high levels of agreement across different patient sub-populations, but lower relevance for neonates and symptomatic HIV patients.

Conclusion

This work highlighted once again the challenges of prioritising in global health, but it also shows that taking a two-pronged approach, combining available prevalence data with expert input, can result in a broadly applicable priority list. This comprehensive utility is particularly important in the context of product development, where a sufficient market size is essential to achieve a sustainable commercialized diagnostic product to address SFWS.

Mandatory Notification of Chronic Chagas Disease: Confronting the Epidemiological Silence in the State of Goiás, Brazil

OBJECTIVES

This paper presents the results of the design and implementation process for the policy of compulsory notification of chronic Chagas disease in the Brazilian state of Goiás (Resolution No. 004/2013-GAB/SES-GO).

METHODS

The narrative was based on information provided by key actors that were part of the different stages of the process, built on contextual axes based on participants' reflections about the establishment of the most accurate and coherent notification mechanisms.

RESULTS

The notification policy addressed the absence of historical data from patients in the state Chagas program, an increase in cases identified through serology, and weaknesses in vector control. Two key challenges involved human resources capacity and dissemination to public agencies and health care workers. Effective training and communication processes were key ingredients for successful implementation.

CONCLUSIONS

The lack of public health measures aimed at the epidemiological surveillance of chronic Chagas cases constitutes a significant barrier for patients to access appropriate diagnosis, management and follow-up, and hampers the planning of necessary activities within health systems. The implementation of the notification policy in Goiás allows authorities to determine the real magnitude of Chagas disease in the population, so that an appropriate public health response can be mounted to meet the needs of affected people, thereby ending the epidemiological silence of Chagas disease.

Screening Marine Natural Products for New Drug Leads against Trypanosomatids and Malaria

Neglected Tropical Diseases (NTD) represent a serious threat to humans, especially for those living in poor or developing countries. Almost one-sixth of the world population is at risk of suffering from these diseases and many thousands die because of NTDs, to which we should add the sanitary, labor and social issues that hinder the economic development of these countries. Protozoan-borne diseases are responsible for more than one million deaths every year. Visceral leishmaniasis, Chagas disease or sleeping sickness are among the most lethal NTDs. Despite not being considered an NTD by the World Health Organization (WHO), malaria must be added to this sinister group. Malaria, caused by the apicomplexan parasite Plasmodium falciparum, is responsible for thousands of deaths each year. The treatment of this disease has been losing effectiveness year after year. Many of the medicines currently in use are obsolete due to their gradual loss of efficacy, their intrinsic toxicity and the emergence of drug resistance or a lack of adherence to treatment. Therefore, there is an urgent and global need for new drugs. Despite this, the scant interest shown by most of the stakeholders involved in the pharmaceutical industry makes our present therapeutic arsenal scarce, and until recently, the search for new drugs has not been seriously addressed. The sources of new drugs for these and other pathologies include natural products, synthetic molecules or repurposing drugs. The most frequent sources of natural products are microorganisms, e.g., bacteria, fungi, yeasts, algae and plants, which are able to synthesize many drugs that are currently in use (e.g. antimicrobials, antitumor, immunosuppressants, etc.). The marine environment is another well-established source of bioactive natural products, with recent applications against parasites, bacteria and other pathogens which affect humans and animals. Drug discovery techniques have rapidly advanced since the beginning of the millennium. The combination of novel techniques that include the genetic modification of pathogens, bioimaging and robotics has given rise to the standardization of High-Performance Screening platforms in the discovery of drugs. These advancements have accelerated the discovery of new chemical entities with antiparasitic effects. This review presents critical updates regarding the use of High-Throughput Screening (HTS) in the discovery of drugs for NTDs transmitted by protozoa, including malaria, and its application in the discovery of new drugs of marine origin.

The relationship between government research funding and the cancer burden in South Korea: implications for prioritising health research

Background

In this study, we aimed to assess health research funding allocation in South Korea by analysing the relationship between government funding and disease burden in South Korea, specifically focusing on cancers.

Methods

The relationship between research funding and the cancer burden, measured in disability-adjusted life-years (DALYs), was analysed using a linear regression method over a 10-year interval. Funding information on 25 types of cancer was obtained from the National Science and Technology Information Service portal in South Korea. Measures of cancer burden were obtained from Global Burden of Disease studies. The funding predictions were derived from regression analysis and compared with actual funding allocations. In addition, we evaluated how the funding distribution reflected long-term changes in the burden and the burden specific to South Korea compared with global values.

Results

Korean funding in four periods, 2005–2007, 2008–2010, 2011–2013 and 2015–2017, were associated with the cancer burden in 2003, 2006, 2009 and 2013, respectively. For DALYs, the correlation coefficients were 0.79 and 0.82 in 2003 and 2013, respectively, which were higher than the values from other countries. However, the changes in DALYs (1990–2006) were not associated with the funding changes (from 2005 to 2007 to 2015–2017). In addition, the value differences between Korean and global DALYs were not associated with Korean government research funding.

Conclusions

Although research funding was associated with the cancer burden in South Korea during the last decade, the distribution of research funds did not appropriately reflect the changes in burden nor the differences between the South Korean and global burden levels. The policy-makers involved in health research budgeting should consider not only the absolute burden values for singular years but also the long-term changes in burden and the country-specific burden when they prioritise public research projects.

Clinical Indicators of Fatal Dengue in Two Endemic Areas of Colombia: A Hospital-Based Case-Control Study

According to the World Health Organization, 98% of fatal dengue cases can be prevented; however, endemic countries such as Colombia have recorded higher case fatality rates during recent epidemics. We aimed to identify the predictors of mortality that allow risk stratification and timely intervention in patients with dengue. We conducted a hospital-based, case-control (1:2) study in two endemic areas of Colombia (2009-2015). Fatal cases were defined as having either 1) positive serological test (IgM or NS1), 2) positive virological test (RT-PCR or viral isolation), or 3) autopsy findings compatible with death from dengue. Controls (matched by state and year) were hospitalized nonfatal patients and had a positive serological or virological dengue test. Exposure data were extracted from medical records by trained staff. We used conditional logistic regression (adjusting for age, gender, disease's duration, and health-care provider) in the context of multiple imputation to estimate exposure to case-control associations. We evaluated 110 cases and 217 controls (mean age: 35.0 versus 18.9; disease's duration pre-admission: 4.9 versus 5.0 days). In multivariable analysis, retro-ocular pain (odds ratios [OR] = 0.23), nausea (OR = 0.29), and diarrhea (OR = 0.19) were less prevalent among fatal than nonfatal cases, whereas increased age (OR = 2.46 per 10 years), respiratory distress (OR = 16.3), impaired consciousness (OR = 15.9), jaundice (OR = 32.2), and increased heart rate (OR = 2.01 per 10 beats per minute) increased the likelihood of death (AUC: 0.97, 95% confidence interval: 0.96, 0.99). These results provide evidence that features of severe dengue are associated with higher mortality, which strengthens the recommendations related to triaging patients in dengue-endemic areas.

Aryl thiosemicarbazones for the treatment of trypanosomatidic infections

Basing on a library of thiadiazole derivatives showing anti-trypanosomatidic activity, we have considered the thiadiazoles opened forms and reaction intermediates, thiosemicarbazones, as compounds of interest for phenotypic screening against Trypanosoma brucei (Tb), intracellular amastigote form of Leishmania infantum (Li) and Trypanosoma cruzi (Tc). Similar compounds have already shown interesting activity against the same organisms. The compounds were particularly effective against T. brucei and T. cruzi. Among the 28 synthesized compounds, the best one was (E)-2-(4-((3.4-dichlorobenzyl)oxy)benzylidene) hydrazinecarbothioamide (A14) yielding a comparable anti-parasitic activity against the three parasitic species (TbEC₅₀ = 2.31 μM, LiEC₅₀ = 6.14 μM, TcEC₅₀ = 1.31 μM) and a Selectivity Index higher than 10 with respect to human macrophages, therefore showing a pan-anti-trypanosomatidic activity. (E)-2-((3'.4'-dimethoxy-[1.1'-biphenyl]-3-yl)methyle ne) hydrazinecarbothioamide (A12) and (E)-2-(4-((3.4-dichlorobenzyl)oxy)benzylidene)hydrazine carbothioamide (A14) were able to potentiate the anti-parasitic activity of methotrexate (MTX) when evaluated in combination against T. brucei, yielding a 6-fold and 4-fold respectively Dose Reduction Index for MTX. The toxicity profile against four human cell lines and a panel of in vitro early-toxicity assays (comprising hERG, Aurora B, five cytochrome P450 isoforms and mitochondrial toxicity) demonstrated the low toxicity for the thosemicarbazones class in comparison with known drugs. The results confirmed thiosemicarbazones as a suitable chemical scaffold with potential for the development of properly decorated new anti-parasitic drugs.

Neglected tropical diseases and global burden of disease in China

Recently, the mortality of 240 causes in China including a subnational analysis during 1990–2013 was published in The Lancet. This comprehensive analysis will undoubtedly impact policymaking regarding public health in China. However, it is unfavourable in some degree to neglected tropical diseases, which is the subject of this Letter to the Editor. Policymakers, especially those in less developed provinces of China, should fully consider the burden of neglected tropical diseases, which will benefit the control and final elimination of these diseases in the country.