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The American Journal of Tropical... Apr 2021
Topics: Animals; Communicable Disease Control; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Humans
PubMed: 33909595
DOI: 10.4269/ajtmh.21-0433 -
MMWR. Morbidity and Mortality Weekly... Nov 2018Dracunculiasis (Guinea worm disease), caused by the parasite Dracunculus medinensis, is acquired by drinking water containing copepods (water fleas) infected with its...
Dracunculiasis (Guinea worm disease), caused by the parasite Dracunculus medinensis, is acquired by drinking water containing copepods (water fleas) infected with its larvae. The worm typically emerges through the skin on a lower limb approximately 1 year after infection, causing pain and disability (1). The worldwide eradication campaign began at CDC in 1980. In 1986, the World Health Assembly called for dracunculiasis elimination, and the global Guinea Worm Eradication Program (GWEP), led by the Carter Center in partnership with the World Health Organization (WHO), United Nations Children's Fund (UNICEF), CDC, and others, began assisting ministries of health in countries with dracunculiasis. There is no vaccine or medicine to treat the disease; the GWEP relies on case containment* to prevent water contamination and other interventions to prevent infection, including health education, water filtration, chemical treatment of water, and provision of safe drinking water (1,2). In 1986, an estimated 3.5 million cases occurred each year in 20 African and Asian countries (3,4). This report, based on updated health ministry data (3), describes progress during January 2017-June 2018 and updates previous reports (1,4). In 2017, 30 cases were reported from Chad and Ethiopia, and 855 infected animals (mostly dogs) were reported from Chad, Ethiopia, and Mali, compared with 25 cases and 1,049 animal infections reported in 2016. During January-June 2018, the number of cases declined to three cases each in Chad and South Sudan and one in Angola, with 709 infected animals reported, compared with eight cases and 547 animal infections during the same period of 2017. With only five affected countries, the eradication goal is near, but is challenged by civil unrest, insecurity, and lingering epidemiologic and zoologic questions.
Topics: Disease Eradication; Dracunculiasis; Global Health; Humans
PubMed: 30439874
DOI: 10.15585/mmwr.mm6745a3 -
MMWR. Morbidity and Mortality Weekly... Oct 2020Dracunculiasis (Guinea worm disease) is caused by the parasite Dracunculus medinensis and is acquired by drinking water containing copepods (water fleas) infected with...
Dracunculiasis (Guinea worm disease) is caused by the parasite Dracunculus medinensis and is acquired by drinking water containing copepods (water fleas) infected with D. medinensis larvae. The worm typically emerges through the skin on a lower limb approximately 1 year after infection, resulting in pain and disability (1). There is no vaccine or medicine to treat the disease; eradication efforts rely on case containment* to prevent water contamination. Other interventions to prevent infection include health education, water filtration, chemical treatment of unsafe water with temephos (an organophosphate larvicide to kill copepods), and provision of safe drinking water (1,2). The worldwide eradication campaign began in 1980 at CDC (1). In 1986, with an estimated 3.5 million cases occurring each year in 20 African and Asian countries (3), the World Health Assembly (WHA) called for dracunculiasis elimination (4). The global Guinea Worm Eradication Program (GWEP), led by the Carter Center and supported by the World Health Organization (WHO), United Nations Children's Fund, CDC, and other partners, began assisting ministries of health in countries with dracunculiasis. This report, based on updated health ministry data (4), describes progress made during January 2019-June 2020 and updates previous reports (2,4,5). With only 54 human cases reported in 2019, 19 human cases reported during January 2019-June 2020, and only six countries currently affected by dracunculiasis (Angola, Chad, Ethiopia, Mali, South Sudan, and importations into Cameroon), the achievement of eradication is within reach, but it is challenged by civil unrest, insecurity, and lingering epidemiologic and zoologic concerns, including 2,000 reported animal cases in 2019 and 1,063 animal cases in 2020, mostly in dogs. All national GWEPs remain fully operational, with precautions taken to ensure safety of program staff members and community members in response to the coronavirus disease 2019 (COVID-19) pandemic.
Topics: Animals; Disease Eradication; Dog Diseases; Dogs; Dracunculiasis; Global Health; Humans
PubMed: 33119555
DOI: 10.15585/mmwr.mm6943a2 -
PLoS Pathogens Nov 2022Neurotransmission is an important target for anthelmintic drugs, where receptor characteristics and response can be examined through reconstitution ex vivo in Xenopus...
Neurotransmission is an important target for anthelmintic drugs, where receptor characteristics and response can be examined through reconstitution ex vivo in Xenopus laevis oocytes. The homomeric ACR-16 nicotine sensitive acetylcholine receptors (N-AChRs) of several helminth species have been characterized in this way. Our efforts to reconstitute the N-AChR from the clade III filarial parasite, Brugia malayi using similar conditions, initially produced no detectable response. A robust response to acetylcholine is obtained from the closely related clade III parasite Ascaris suum, suggesting that specific changes have occurred between Ascaris and Brugia. N-AChRs from three species intermediate between A. suum and B. malayi were characterized to provide information on the cause. Maximal response to acetylcholine did not change abruptly, consistent with a discrete event, but rather decreased progressively from A. suum through Dracunculus medinensis, Gonglylonema pulchrum and Thelazia callipaeda. Receptor responses to the characteristic nicotine, and other agonists were generally similar. The decrease in maximal current did correlate with a delayed time to reach larger response. Together, this suggested that the failure to reconstitute the B. malayi N-AChR was one extreme of a progressive decrease and that an issue with synthesis of the receptor in oocytes was responsible. Addition of accessory proteins EMC-6, NRA-2 and NRA-4, in addition to RIC-3, produced a small, but measurable B. malayi N-AChR response. Pharmacological properties of a chimeric B. malayi N-AChR were equivalent to the other species, confirming the receptor response remains unchanged while its production is increasingly dependent on accessory proteins. One possibility is that loss of many subunits for acetylcholine receptors from the filarial nematode genome is linked to new subunit combinations that lead to such a dependence. This novel phylogenetic approach allowed the first characterization of a B. malayi AChR ex vivo and in doing so, provides a framework for the successful characterization of other receptors that have yet to be reconstituted.
Topics: Animals; Brugia malayi; Parasites; Acetylcholine; Nicotine; Phylogeny; Receptors, Cholinergic; Receptors, Nicotinic
PubMed: 36374934
DOI: 10.1371/journal.ppat.1010962 -
Emerging Infectious Diseases Nov 2016A third-stage (infective) larva of Dracunculus medinensis, the causative agent of Guinea worm disease, was recovered from a wild-caught Phrynobatrachus francisci frog in...
A third-stage (infective) larva of Dracunculus medinensis, the causative agent of Guinea worm disease, was recovered from a wild-caught Phrynobatrachus francisci frog in Chad. Although green frogs (Lithobates clamitans) have been experimentally infected with D. medinensis worms, our findings prove that frogs can serve as natural paratenic hosts.
Topics: Animals; Anura; Chad; Dracunculiasis; Dracunculus Nematode; Helminthiasis, Animal; Larva
PubMed: 27560598
DOI: 10.3201/eid2211.161332 -
PLoS Neglected Tropical Diseases Jan 2021A number of neglected tropical diseases are targeted for elimination or eradication. An effective surveillance system is critical to determine if these goals have been... (Review)
Review
Lessons learned for surveillance strategies for trachoma elimination as a public health problem, from the evaluation of approaches utilised by Guinea worm and onchocerciasis programmes: A literature review.
INTRODUCTION
A number of neglected tropical diseases are targeted for elimination or eradication. An effective surveillance system is critical to determine if these goals have been achieved and maintained. Trachoma has two related but morphologically different presentations that are monitored for elimination, the active infectious form of trachoma and trachomatous trichiasis (TT), the progression of the disease. There are a number of lessons learnt from the Guinea worm surveillance system that are particularly compatible for TT surveillance and the onchocerciasis surveillance system which can provide insights for surveillance of the infectious form of trachoma.
METHODS/PRINCIPAL FINDINGS
A literature search of peer-reviewed published papers and grey literature was conducted using PUBMED and Google Scholar for articles relating to dracunculiasis or Guinea worm, onchocerciasis and trachoma, along with surveillance or elimination or eradication. The abstracts of relevant papers were read and inclusion was determined based on specified inclusion and exclusion criteria. The credibility and bias of relevant papers were also critically assessed using published criteria. A total of 41 papers were identified that were eligible for inclusion into the review. The Guinea worm programme is designed around a surveillance-containment strategy and combines both active and passive surveillance approaches, with a focus on village-based surveillance and reporting. Although rumour reporting and a monetary incentive for the identification of confirmed Guinea worm cases have been reported as successful for identifying previously unknown transmission there is little unbiased evidence to support this conclusion. More rigorous evidence through a randomised controlled trial, influenced by motivational factors identified through formative research, would be necessary in order to consider applicability for TT case finding in an elimination setting. The onchocerciasis surveillance strategy focuses on active surveillance through sentinel surveillance of villages and breeding sites. It relies on an entomological component, monitoring infectivity rates of black flies and an epidemiological component, tracking exposure to infection in humans. Challenges have included the introduction of relatively complex diagnostics that are not readily available in onchocerciasis endemic countries and target thresholds, which are practically unattainable with current diagnostic tests. Although there is utility in monitoring for infection and serological markers in trachoma surveillance, it is important that adequate considerations are made to ensure evidence-based and achievable guidelines for their utility are put in place.
CONCLUSIONS/SIGNIFICANCE
The experiences of both the Guinea worm and onchocerciasis surveillance strategies have very useful lessons for trachoma surveillance, pre- and post-validation. The use of a monetary reward for identification of TT cases and further exploration into the use of infection and serological indicators particularly in a post-validation setting to assist in identifying recrudescence would be of particular relevance. The next step would be a real-world evaluation of their relative applicability for trachoma surveillance.
Topics: Animals; Databases, Factual; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Health Surveys; Humans; Onchocerciasis; Prevalence; Public Health; Trachoma; Trichiasis
PubMed: 33507903
DOI: 10.1371/journal.pntd.0009082 -
The American Journal of Tropical... Nov 2020The campaign to eradicate dracunculiasis (Guinea worm [GW] disease) and its causative pathogen (GW) in Chad is challenged by infections in domestic dogs, which far...
The campaign to eradicate dracunculiasis (Guinea worm [GW] disease) and its causative pathogen (GW) in Chad is challenged by infections in domestic dogs, which far outnumber the dwindling number of human infections. We present an agent-based simulation that models transmission of GW between a shared water source and a large population of dogs. The simulation incorporates various potential factors driving the infections including external factors and two currently used interventions, namely, tethering and larvicide water treatments. By defining and estimating infectivity parameters and seasonality factors, we test the simulation model on scenarios where seasonal patterns of dog infections could be driven by the parasite's life cycle alone or with environmental factors (e.g., temperature and rainfall) that could also affect human or dog behaviors (e.g., fishing versus farming seasons). We show that the best-fitting model includes external factors in addition to the pathogen's life cycle. From the simulation, we estimate that the basic reproductive number, , is approximately 2.0; our results also show that an infected dog can transmit the infection to 3.6 other dogs, on average, during the month of peak infectivity (April). The simulation results shed light on the transmission dynamics of GWs to dogs and lay the groundwork for reducing the number of infections and eventually interrupting transmission of GW.
Topics: Animals; Chad; Computer Simulation; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Environment; Female; Life Cycle Stages; Models, Theoretical; Seasons; Temperature; Water
PubMed: 32901603
DOI: 10.4269/ajtmh.19-0466 -
BMJ Open Aug 2021To quantify conflict events and access across countries that remain to be certified free of transmission of (Guinea worm disease) or require postcertification...
OBJECTIVES
To quantify conflict events and access across countries that remain to be certified free of transmission of (Guinea worm disease) or require postcertification surveillance as part of the Guinea Worm Eradication Programme (GWEP).
SETTING AND PARTICIPANTS
Populations living in Guinea worm affected areas across seven precertification countries and 13 postcertification sub-Saharan African countries.
OUTCOME MEASURES
The number of conflict events and rates per 100 000 population, the main types of conflict and actors reported to be responsible for events were summarised and mapped across all countries. Chad and Mali were presented as case studies. Guinea worm information was based on GWEP reports. Conflict data were obtained from the Armed Conflict Location and Event Data Project. Maps were created using ArcGIS V.10.7 and access was measured as regional distance and time to cities.
RESULTS
More than 980 000 conflict events were reported between 2000 and 2020, with a significant increase since 2018. The highest number and rates were reported in precertification Mali (n=2556; 13.0 per 100 000), South Sudan (n=2143; 19.4), Democratic Republic of Congo (n=7016; 8.1) and postcertification Nigeria (n=6903; 3.4), Central Africa Republic (n=1251; 26.4), Burkina Faso (n=2004; 9.7). Violence against civilians, protests and battles were most frequently reported with several different actors involved including Unidentified Armed Groups and Boko Haram. Chad and Mali had contracting epidemiological and conflict situations with affected regions up to 700 km from the capital or 10 hours to the nearest city.
CONCLUSIONS
Understanding the spatial-temporal patterns of conflict events, identifying hotspots, the actors responsible and their sphere of influence is critical for the GWEP and other public health programmes to develop practical risk assessments, deliver essential health interventions, implement innovative surveillance, determine certification and meet the goals of eradication.
Topics: Animals; Burkina Faso; Certification; Dracunculiasis; Dracunculus Nematode; Humans; Mali
PubMed: 34353803
DOI: 10.1136/bmjopen-2021-049732 -
The National Medical Journal of India 2023The article 'Guinea-worm (Dracunculus medinensis) infection presenting as a diabetic foot abscess: A case report from Kerala is being retracted based on a letter...
The article 'Guinea-worm (Dracunculus medinensis) infection presenting as a diabetic foot abscess: A case report from Kerala is being retracted based on a letter received from the Director of the National Centre of Disease Control, New Delhi where the centre has objected to the identification of the guinea-worm by the authors only on the basis of morphological observation, without any microscopic and histopathological examination. The author has agreed to the objection and to the withdrawal of the article. This article is therefore being retracted. PEUSH SAHNI Editor The National Medical Journal of India All India Institute of Medical Sciences, New Delhi, India [email protected].
PubMed: 37615131
DOI: 10.25259/NMJI-32-22_ER -
MMWR. Morbidity and Mortality Weekly... Oct 2015Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after a person acquires infection from contaminated...
Dracunculiasis (Guinea worm disease) is caused by Dracunculus medinensis, a parasitic worm. Approximately 1 year after a person acquires infection from contaminated drinking water, the worm emerges through the skin, usually on the lower limb. Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. The campaign to eradicate dracunculiasis worldwide began in 1980 at CDC. In 1986, the World Health Assembly called for dracunculiasis elimination, and the global Guinea Worm Eradication Program, led by the Carter Center and supported by the World Health Organization (WHO), United Nations Children's Fund (UNICEF), CDC, and other partners, began assisting ministries of health in countries where dracunculiasis was endemic. In 1986, an estimated 3.5 million cases occurred each year in 20 countries in Africa and Asia. Since then, although the goal of eradicating dracunculiasis has not been achieved, considerable progress has been made. Compared with the 1986 estimate, the annual number of reported cases in 2015 has been reduced by 99% and cases are confined to four endemic countries. This report updates published and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication from January 2014 through June 2015. During 2014, a total of 126 cases were reported from four countries (Chad [13 cases], Ethiopia [three], Mali [40], and South Sudan [70]), compared with 148 cases reported in 2013, from the same four countries. The overall 15% reduction in cases during 2013–2014 was less than that experienced in recent years, but the rate of decline increased again to 70% in the first 6 months of 2015 compared with the same period during 2014. Continued active surveillance with aggressive detection and appropriate management of cases are essential program components; however, epidemiologic challenges and civil unrest and insecurity pose potential barriers to eradication.
Topics: Disease Eradication; Dracunculiasis; Global Health; Humans
PubMed: 26492134
DOI: 10.15585/mmwr.mm6441a1