Neglected tropical diseases, bioinformatics, and vaccines

Global, regional, national epidemiology and trends of neglected tropical diseases in youths and young adults aged 15-39 years from 1990 to 2019: findings from the global burden of disease study 2019

BACKGROUND

In recent years, the escalating concern for neglected tropical diseases (NTDs) has been recognized as a pressing global health issue. This concern is acutely manifested in low- and middle-income countries, where there is an escalating prevalence among adolescents and young adults. The burgeoning of these conditions threatens to impair patients' occupational capabilities and overall life quality. Despite the considerable global impact of NTDs, comprehensive studies focusing on their impact in younger populations remain scarce. Our study aims to describe the global prevalence of neglected tropical diseases among people aged 15 to 39 years over the 30-year period from 1990 to 2019, and to project the disease burden of the disease up to 2040.

METHODS

Annual data on incident cases, mortality, and disability-adjusted life years (DALYs) for NTDs were procured from the Global Burden of Disease Study 2019 (GBD 2019). These data were stratified by global and regional distribution, country, social development index (SDI), age, and sex. We computed age-standardized rates (ASRs) and the numbers of incident cases, mortalities, and DALYs from 1990 to 2019. The estimated annual percentage change (EAPC) in the ASRs was calculated to evaluate evolving trends.

RESULTS

In 2019, it was estimated that there were approximately 552 million NTD cases globally (95% Uncertainty Interval [UI]: 519.9 million to 586.3 million), a 29% decrease since 1990. South Asia reported the highest NTD prevalence, with an estimated 171.7 million cases (95% UI: 150.4 million to 198.6 million). Among the five SDI categories, the prevalence of NTDs was highest in the moderate and low SDI regions in 1990 (approximately 270.5 million cases) and 2019 (approximately 176.5 million cases). Sub-Saharan Africa recorded the most significant decline in NTD cases over the past three decades. Overall, there was a significant inverse correlation between the disease burden of NTDs and SDI.

CONCLUSION

NTDs imposed over half a billion incident cases and 10.8 million DALYs lost globally in 2019-exerting an immense toll rivaling major infectious and non-communicable diseases. Encouraging declines in prevalence and disability burdens over the past three decades spotlight the potential to accelerate progress through evidence-based allocation of resources. Such strategic integration could substantially enhance public awareness about risk factors and available treatment options.

Advancing vaccine development against Opisthorchis viverrini: A synergistic integration of omics technologies and advanced computational tools

The liver fluke O. viverrini (Opisthorchis viverrini), a neglected tropical disease (NTD), endemic to the Great Mekong Subregion (GMS), mainly afflicts the northeastern region of Thailand. It is a leading cause of cholangiocarcinoma (CCA) in humans. Presently, the treatment modalities for opisthorchiasis incorporate the use of the antihelminthic drug praziquantel, the rapid occurrence of reinfection, and the looming threat of drug resistance highlight the urgent need for vaccine development. Recent advances in "omics" technologies have proven to be a powerful tool for such studies. Utilizing candidate proteins identified through proteomics and refined via immunoproteomics, reverse vaccinology (RV) offers promising prospects for designing vaccines targeting essential antibody responses to eliminate parasite. Machine learning-based computational tools can predict epitopes of candidate protein/antigens exhibiting high binding affinities for B cells, MHC classes I and II, indicating strong potential for triggering both humoral and cell-mediated immune responses. Subsequently, these vaccine designs can undergo population-specific testing and docking/dynamics studies to assess efficacy and synergistic immunogenicity. Hence, refining proteomics data through immunoinformatics and employing computational tools to generate antigen-specific targets for trials offers a targeted and efficient approach to vaccine development that applies to all domains of parasite infections. In this review, we delve into the strategic antigen selection process using omics modalities for the O. viverrini parasite and propose an innovative framework for vaccine design. We harness omics technologies to revolutionize vaccine development, promising accelerated discoveries and streamlined preclinical and clinical evaluations.

Prediction and validation of the structural features of Ov58GPCR, an immunogenic determinant of Onchocerca volvulus

Onchocerciasis is a severely debilitating yet neglected tropical disease (NTD) that creates social stigma, generates and perpetuates poverty, and leads ultimately in some cases to irreversible unilateral or bilateral blindness if untreated. Consequently, the disease is a major impediment to socioeconomic development. Many control programs have been launched for the disease with moderate successes achieved. This mitigated hit is partially due to the lingering need for reliable, non-invasive and easily applicable tools for mapping endemic regions and post-elimination surveillance. In this work, bioinformatics analyses combined with immunological assays were applied in a bid to develop potential tools for diagnosis and assessing the success of drug treatment programs. We report that (i) the O. volvulus antigen, Ov58GPCR is a G-protein coupled receptor (GPCR) conserved in related nematodes, (ii) synthetic peptides predicted to be in the extracellular domain (ECD) of Ov58GPCR are indeed immunogenic epitopes in actively-infected individuals, (iii) synthetic peptide cocktails discriminate between actively-infected individuals, treated individuals and healthy African controls, (iv) polyclonal antibodies against one of the peptides or against the bacterially-expressed ECD reacted specifically with the native antigen of O. volvulus total and surface extracts, (v) Ov58GPCR is transcribed in both larvae and adult parasite stages, (vi) IgG and IgE responses to the recombinant ECD decline with ivermectin treatment. All these findings suggest that the extracellular domain and synthetic peptides of Ov58GPCR, as well as the specific immune response generated could be harnessed in the context of disease diagnosis and surveillance.