The rise or fall of neglected tropical diseases in East Asia Pacific

Understanding how neglected tropical diseases programs in five Asia-Pacific countries adjusted to the COVID-19 pandemic: A qualitative study

BACKGROUND

Following the COVID-19 pandemic declaration, the World Health Organization recommended suspending neglected tropical diseases (NTD) control activities as part of sweeping strategies to minimise COVID-19 transmission. Understanding how NTD programs were impacted and resumed operations will inform contingency planning for future emergencies. This is the first study that documents how South-East Asian and Pacific NTD programs addressed challenges experienced during the COVID-19 pandemic.

METHODOLOGY/PRINCIPAL FINDINGS

Data was collected through semi-structured interviews with 11 NTD Program Coordinators and related personnel from Fiji, Papua New Guinea, The Philippines, Timor-Leste, and Vanuatu. Constructivist grounded theory methods were drawn on to generate an explanation of factors that enabled or hindered NTD program operations during the COVID-19 pandemic. The COVID-19 pandemic disrupted NTD programs in all countries. Some programs implemented novel strategies by partnering with services deemed essential or used new communications technology to continue (albeit scaled-back) NTD activities. Strong relationships to initiate cross-program integration, sufficient resources to implement adapted activities, and dedicated administrative systems were key enabling factors for recommencement. As the COVID-19 pandemic continued, exacerbating health resources scarcity, programs faced funding shortages and participants needed to find efficiencies through greater integration and activity prioritisation within their NTD units. Emphasising community-led approaches to restore trust and engagement was critical after widespread social anxiety and disconnection.

CONCLUSIONS/SIGNIFICANCE

Sustaining effective NTD programs during a global emergency goes beyond managing immediate activity disruptions and requires attention to how NTD programs can be better ensconced within wider health programs, administrative, and social systems. This study underscores the importance of pre-emergency planning that reinforces NTD control programs as a critical service at all health systems levels, accompanied by governance arrangements that increase NTD staff control over their operations and strategies to maintain strong community relationships. Ensuring NTD units are supported via appropriate funding, personnel, and bureaucratic resources is also required.

Establishment and application of unbiased in vitro drug screening assays for the identification of compounds against Echinococcus granulosus sensu stricto

Echinococcus multilocularis and E. granulosus s.l. are the causative agents of alveolar and cystic echinococcosis, respectively. Drug treatment options for these severe and neglected diseases are limited to benzimidazoles, which are not always efficacious, and adverse side effects are reported. Thus, novel and improved treatments are needed. In this study, the previously established platform for E. multilocularis in vitro drug assessment was adapted to E. granulosus s.s. In a first step, in vitro culture protocols for E. granulosus s.s. were established. This resulted in the generation of large amounts of E. granulosus s.s. metacestode vesicles as well as germinal layer (GL) cells. In vitro culture of these cells formed metacestode vesicles displaying structural characteristics of metacestode cysts generated in vivo. Next, drug susceptibilities of E. multilocularis and E. granulosus s.s. protoscoleces, metacestode vesicles and GL cells were comparatively assessed employing established assays including (i) metacestode vesicle damage marker release assay, (ii) metacestode vesicle viability assay, (iii) GL cell viability assay, and (iv) protoscolex motility assay. The standard drugs albendazole, buparvaquone, mefloquine, MMV665807, monepantel, niclosamide and nitazoxanide were included. MMV665807, niclosamide and nitazoxanide were active against the parasite in all four assays against both species. MMV665807 and monepantel were significantly more active against E. multilocularis metacestode vesicles, while albendazole and nitazoxanide were significantly more active against E. multilocularis GL cells. Albendazole displayed activity against E. multilocularis GL cells, but no effects were seen in albendazole-treated E. granulosus s.s. GL cells within five days. Treatment of protoscoleces with albendazole and monepantel had no impact on motility. Similar results were observed for both species with praziquantel and its enantiomers against protoscoleces. In conclusion, in vitro culture techniques and drug screening methods previously established for E. multilocularis were successfully implemented for E. granulosus s.s., allowing comparisons of drug efficacy between the two species. This study provides in vitro culture techniques for the reliable generation of E. granulosus s.s. metacestode vesicles and GL cell cultures and describes the validation of standardized in vitro drug screening methods for E. granulosus s.s.

Incidence and mortality trends of neglected tropical diseases and malaria in China and ASEAN countries from 1990 to 2019 and its association with the socio-demographic index

BACKGROUND

People in China and the countries in the Association of Southeast Asian Nations (ASEAN) are affected by neglected tropical diseases and malaria (NTDM). In this study, we aimed to assess the current status and trends of NTDM burden from 1990 to 2019 in China and ASEAN countries, and also explore the association of NTDM burden with socio-demographic index (SDI).

METHODS

The data from the Global Burden of Diseases Study 2019 (GBD 2019) results were used. Absolute incidence and death number, and age-standardized incidence and mortality rate (ASIR and ASMR) of NTDM in China and ASEAN were extracted. The estimated annual percentage change (EAPC) and join-point regression in the rates quantified the trends. Nonlinear regression (second order polynomial) was used to explore the association between SDI and ASRs.

RESULTS

The ASIR of NTDM increased in China, Philippines, Singapore and Brunei, at a speed of an average 4.15% (95% CI 3.83-4.47%), 2.15% (1.68-2.63%), 1.03% (0.63-1.43%), and 0.88% (0.60-1.17%) per year. Uptrends of ASIR of NTDM in recent years were found in China (2014-2017, APC = 10.4%), Laos (2005-2013, APC = 3.9%), Malaysia (2010-2015, APC = 4.3%), Philippines (2015-2019, APC = 4.2%), Thailand (2015-2019, APC = 2.4%), and Vietnam (2014-2017, APC = 3.2%, all P < 0.05). Children < 5 had relatively low incidences but unexpectedly high mortality rates of NTDM in most ASEAN countries. Both incidence and mortality rates of NTDM were higher in older people. ASIR and ASMR of NTDM had a U-shaped association with SDI.

CONCLUSIONS

The burden of NTDM in China and ASEAN countries was still huge and affects vulnerable and impoverished populations' livelihoods, including children under the age of 5 and people aged 60 and older. Facing with the large burden and complex situation of NTDM in China and ASEAN countries, regional cooperating strategies are needed to reduce the burden of NTDM, so as to achieve the goal of elimination in the world.

Soil-transmitted helminthic vaccines: Where are we now?

It has been tested and proven that vaccination is still the best strategy to combat infectious diseases. However, to date, there are still no vaccines against human soil-transmitted helminthic diseases, despite their high prevalence globally, particularly in developing countries and rural areas with tropical climates and poor sanitation. The development of vaccines against helminths is riddled with obstacles. Helminths have a complex life cycle, multiple stages within the same host with stage-specific antigen expression, and the ability to regulate host immune reactions to evade the immune response. These elements contribute to the main challenge of helminthic vaccines: the identification of effective vaccine candidates. Therefore, this article reviews the current progress and potential future direction of soil-transmitted helminthic vaccines, particularly against Trichuris trichiura, Ascaris lumbricoides, Strongyloides stercoralis, Necator americanus and Ancylostoma duodenale. The study design employed was a systematic review, using qualitative meta-summary synthesis. Preclinical studies and clinical trials on the development of protein subunit vaccines against the five soil-transmitted helminths were searched on PubMed and Scopus. Effectiveness was indicated by a reduction in worm burden or larval output, an increase in specific IgG levels, or an increase in cytokine production. Our findings show that only the hookworm vaccine against N. americanus is in the clinical trial phase, while the rest is still in exploratory research and pre-clinical development phase.

Mass drug administration for endemic scabies: a systematic review

BACKGROUND

Scabies is an extremely fastidious infestation caused by the Sarcoptes scabiei mite. It causes a persistent itch that can disrupt a person's mental health, sleep, and overall quality of life. In endemic areas, treatment by targeting symptomatic individuals and their contacts is often unsuccessful due to an asymptomatic period and high rates of re-infection. To overcome this, Mass Drug Administration (MDA) is often used to treat the whole community, irrespective of whether individuals presently have scabies. This review summarises the evidence for the effectiveness of MDA in treating scabies.

METHODS

An exhaustive literature review was conducted on MEDLINE, EMBASE, Web of Science and Scopus. All peer-reviewed articles published in English January 1990 to March 2020 were eligible and only if the studies were primary and interventional. Furthermore, the intervention had to be a pharmacological MDA method involving human subjects.

RESULTS

TWELVE articles that qualified for inclusion were identified. MDA for scabies significantly reduced its prevalence in communities at follow up. Some of the drivers of success were communities with low levels of migration, an uptake of MDA of > 85%, the use of oral Ivermectin therapy, the treatment of children and pregnant women within the treated population, and repeated treatment for participants diagnosed with scabies at baseline.

CONCLUSIONS

The average absolute reduction in prevalence of scabies was 22.0% and the relative reduction average was 73.4%. These results suggest MDA is effective in treating scabies in the endemic community. Further evidence is needed surrounding MDA use in urban areas with increased levels of migration. Importantly, MDA should not substitute the tackling of socioeconomic factors which contribute to endemic disease such as good sanitation and hygiene.

New global targets for NTDs in the WHO roadmap 2021-2030

The second World Neglected Tropical Diseases (NTDs) Day was celebrated on 30 January 2021. To mark the occasion, the World Health Organization (WHO) launched its roadmap for NTDs for the period 2021 to 2030, which is aimed at increasing prevention and control of these too-long neglected diseases. Described here is a global overview on past achievements, current challenges, and future prospects for the WHO NTDs roadmap 2021–2030.

Soil-Transmitted Helminth Vaccines: Are We Getting Closer?

Parasitic helminths infect over one-fourth of the human population resulting in significant morbidity, and in some cases, death in endemic countries. Despite mass drug administration (MDA) to school-aged children and other control measures, helminth infections are spreading into new areas. Thus, there is a strong rationale for developing anthelminthic vaccines as cost-effective, long-term immunological control strategies, which, unlike MDA, are not haunted by the threat of emerging drug-resistant helminths nor limited by reinfection risk. Advances in vaccinology, immunology, and immunomics include the development of new tools that improve the safety, immunogenicity, and efficacy of vaccines; and some of these tools have been used in the development of helminth vaccines. The development of anthelminthic vaccines is fraught with difficulty. Multiple lifecycle stages exist each presenting stage-specific antigens. Further, helminth parasites are notorious for their ability to dampen down and regulate host immunity. One of the first significant challenges in developing any vaccine is identifying suitable candidate protective antigens. This review explores our current knowledge in lead antigen identification and reports on recent pre-clinical and clinical trials in the context of the soil-transmitted helminths Trichuris, the hookworms and Ascaris. Ultimately, a multivalent anthelminthic vaccine could become an essential tool for achieving the medium-to long-term goal of controlling, or even eliminating helminth infections.