International Health最新文献

Background: Chad onchocerciasis program is conducting several onchocerciasis surveillance activities to verify the interruption of the disease transmission and deciding to stop the MDA ongoing in the country since 1998.

Methods: Entomological surveillance was conducted from June 2021 to February 2022 in the onchocerciasis persistence focus of Oulibangala, Chad.

Results: A total of 6 962 Simulium spp. Blackflies were collected near Oulibangala (n=5 871) and Kaitia (n=1181). Vector blackflies were pooled and tested for O. volvulus DNA using O-150 PCR.

Conclusions: No O. volvulus infections were detected, suggesting potential interruption of transmission in the area.

Background: Having a Simulium vector distribution map is important for all entomological and epidemiological aspects for the elimination of onchocerciasis. Developing these maps using topographic maps has some limitations such as identifying the exact locations of rapids especially with low-scale maps. This leads to breeding sites being missed during prospection. Recent efforts to map breeding sites involve the development of technologies such as satellite images, remote sensing modelling and drones. The limitation to these technologies include cost, security concerns and tree cover preventing the observation of rapids from the sky. Although community support has traditionally been used to guide entomological teams during prospection for breeding sites, community knowledge has not been an integral part in planning breeding site surveys.

Proposed approach: This paper proposes a concept of using community knowledge and health system structure for planning and implementation of breeding sites surveys. The approach uses questionnaires to gather information on fast-flowing stretches of rivers within communities. Using this information, a breeding site survey plan is developed at the national level, and reviewed and implemented at the districts and sub-districts levels using discussions, photos and videos of fast flowing rivers; and topographic maps. A working timetable is then developed which indicates areas to visit each day, maximizing time in the field and other logistics.

Conclusion: Using the health system structures and community members not only provides a rapid approach for entomological surveys, but also strengthens entomological fieldwork and fosters community engagement in vector surveillance.

Background: Defining the transmission zones for onchocerciasis is a critical first step needed in an endemic country aiming at eliminating the transmission of onchocerciasis. The process focuses on defining the geographical boundaries of areas where onchocerciasis transmission could persist with minimal influence from neighbouring regions. The use of operational transmission zones (OTZ) allows for assessment of interruption of onchocerciasis transmission with greater certainty within endemic countries.

Methods: We used available environmental, epidemiological, and entomological data on onchocerciasis in Burkina Faso from the OCP program to the present day. This information, together with field assessment allowed delineation of OTZs across the whole country.

Results: Six OTZs were identified: Comoé-Léraba, Dienkoa, Bas-Mouhoun, Volta, Boucle du Mouhoun and Gourma.

Conclusion: The delineation of the operational onchocerciasis OTZs of Burkina Faso will facilitates the implementation of futures interventions and assessment of the progress towards the disease elimination within the country and bordering regions.

The END Fund's Field Entomology Mentorship Program addresses a critical gap in trained entomologists supporting onchocerciasis elimination in Africa. Unlike conventional training, this hands-on mentorship equips early to mid-career entomologists with technical expertise in critical onchocerciasis blackfly surveillance activities. The three-year program follows a phased approach, gradually increasing mentees' independence while ensuring strong mentorship. In its inaugural year, six mentees engaged in field activities across multiple countries, contributing to the development of elimination strategies, onchocerciasis surveillance, and research projects. Mentees highlight the program's transformative impact, fostering leadership, collaboration, and strategic problem-solving. Their experiences with their mentors have strengthened national program capacity and the program is building a network of skilled experts dedicated to disease elimination. As the program evolves, mentees will take on more independent roles, ensuring sustainable expertise at the country level. This initiative underscores the importance of investing in local entomological capacity to accelerate onchocerciasis elimination efforts across Africa and other endemic countries.

The current guidelines for stopping treatment and verifying elimination of onchocerciasis recommend entomological and epidemiological surveys to be performed during the peak transmission season, which is generally assumed to occur during the rainy season-although this may not necessarily hold true in all transmission zones (TZ). This review has synthesized data, from literature search, on the effects of seasonality on transmission in West and Central Africa. Seasonality affects vector population dynamics by altering terrestrial and aquatic ecology. In TZs with perennial rivers, peak transmission and peak vector density may either coincide or occur at different periods. These peaks could occur in either the rainy or the dry season in both forest and savanna zones, and the periods may change between years. Therefore, countries should establish updated local biting patterns at a TZ prior to vector collection. Also, while using peak biting density as a convenient indicator for when to commence vector collection (because of the need for sufficient sample size), the survey period should include months in both seasons to increase chances of collecting during peak transmission. Seasonality significantly impacts onchocerciasis transmission elimination; and it also offers critical avenues for effective intervention and transmission evaluation.

Background: Former OCP countries like Senegal have made important progress towards eliminating onchocerciasis. Senegal has engaged in post-MDA activities, mainly entomological surveillance, but the country initially struggled to collect the recommended number of blackflies in all the country' transmission zones. Here we implemented a simple approach in the entomological surveillance protocol to increase the number of S. damnosum collected.

Methods: The study was conducted over two consecutive years, 2022 and 2023, in the main S. damnosum capture points located along the Gambie and the Faleme river basins. We reviewed environmental data, analysed and interpreted previous blackflies capture data, and processed field visits to identify optimal periods of blackfly capture in each capture point.

Results: After the implementation of our approach, the number of blackflies captured increased by approximately 42% in 2023 when compared to 2022 captures. The numbers of blackflies captured increased from 71 999 and 23 666 respectively in Gambia and Falemé in 2022, to 101 276 and 34 780 in 2023.

Conclusion: Our results revealed that simple and effective microplanning of blackfly capture periods can support onchocerciasis post-MDA surveillance activities by increasing the number of blackflies captured.

Background: River blindness, caused by Onchocerca volvulus and transmitted by Simulium damnosum s.l., requires robust and ethical vector surveillance for its elimination. The Human Landing Catch (HLC) remains the gold standard for collecting blackflies but presents ethical and operational challenges. This review evaluates alternative blackfly collection methods in relation to their effectiveness, consistency, operational feasibility, and alignment with a Target Product Profile (TPP) framework for field programmatic use.

Methods: Following PRISMA-ScR guidelines, PubMed, Web of Science, WHO IRIS, Scopus, and Google Scholar were searched up to June 2024 using terms related to blackfly traps, vector collection, and onchocerciasis. Peer-reviewed and selected grey literature in English and French were included. Data were thematically synthesised and grouped by trap type, assessing performance against defined TPP criteria.

Results: Fifteen studies met inclusion criteria. The Esperanza Window Trap (EWT) and Host Decoy Trap (HDT) achieved high catches in some settings, occasionally matching or surpassing HLC performance, though results varied by ecology. Modified HLC methods reduced exposure while maintaining yields but still required human participation.

Conclusion: No single alternative method consistently matched HLC across settings; however, optimized EWT and HDT designs show promise for ethical, effective onchocerciasis surveillance.

Background: Maternal schistosomiasis threatens the health of pregnant women and their foetuses in endemic regions. Although praziquantel is recommended for treatment, its utilization remains low. This study explored the experiences of healthcare providers (HCPs) with schistosomiasis, particularly maternal schistosomiasis, and their perceived management barriers in Tanzania.

Methods: This qualitative case study was conducted in October 2024 with nine purposefully selected HCPs. In-depth interviews guided by a semi-structured tool analysed HCPs' experiences with schistosomiasis, maternal schistosomiasis and perceived management barriers. Interviews were audio recorded, transcribed verbatim and thematically analysed to identify key insights and barriers.

Results: Barriers to maternal schistosomiasis management were identified across three levels. At the policy level, the absence of guidance on diagnosis, treatment and prophylaxis in maternal health guidelines, along with the exclusion of pregnant women from mass drug administration programs, were prominent. Health system barriers included limited knowledge and training among HCPs and concerns about praziquantel safety in pregnancy. At the community level, inadequate health education, misconceptions, reliance on drug outlets and negative perceptions of praziquantel further impeded effective management.

Conclusions: Maternal schistosomiasis management in Tanzania is hindered by policy gaps, limited HCP training and community misconceptions. Integrating care into antenatal services, updating guidelines and strengthening community education are essential in endemic settings.

Introduction: As countries progress from control of onchocerciasis as a public health problem to elimination of parasite transmission, more evidence on vector-related activities and transmission assessments is needed to inform WHO guidelines and country strategies to achieve the targets of the 2030 NTD Roadmap. For vector-borne diseases, entomology plays a critical role in the elimination and verification of transmission based on vector infectivity. The vector-control based Onchocerciasis Control Programme in West Africa (OCP, 1974-2002), had accumulated relevant experience and data. The African Programme for Onchocerciasis Control (APOC, 1995-2015) extended onchocerciasis control, based primarily on mass ivermectin administration, to all African endemic countries, and supported many implementation research projects. OCP and APOC documents, previously available only in hard-copy from OCP or APOC, are now accessible in the WHO Institutional Repository for Information Sharing (WHO IRIS). Most documents cover numerous topics and include large amounts of unpublished data. Here, we provide an overview of the OCP and APOC documents in IRIS.

Methods: We reviewed and summarized the documents in WHO IRIS as a resource to guide current elimination efforts. We also provided examples for potential uses of the information for mapping, diagnostics, entomology and social science research to the preparation of elimination dossiers.

Results: The APOC Collection included 8150 documents. Of these, 3895 were in English and 4194 in French. Topics covered in the documents include CDTi, cytotaxonomy, diagnosis, drug effectiveness, environmental modification, epidemiology, health economics, impact assessment, insecticide resistance, larviciding, mapping, programme implementation, slash and burn, transmission assessment and vector control.

Conclusion: The APOC Collection in WHO IRIS makes the wealth of OCP and APOC experience and data available to the onchocerciasis control/elimination and research community.

Forced migration is a result of variable changes, including human-made factors, environmental factors or both. Climate change has been a significant cause of increased forced migration in Sudan. The prolonged drought attributed to climate change affects Sudanese citizens, with 80% of the population relying on agriculture and pastoralism as their main source of income. Since April 2023, the conflict has displaced over 14.5 million people. Four million have sought safety in neighbouring countries. The refugee camps lack essential resources, and the displaced people face a health crisis, with outbreaks of cholera, 30% of children facing malnutrition and widespread mental health issues. Access to sustainable WASH (water, sanitation and hygiene) systems, improved healthcare, mass vaccinations and climate-sensitive interventions are key to mitigation efforts. The ongoing conflict in Sudan demands a coordinated response from the Sudanese government, humanitarian agencies and international partners to prevent further catastrophe.