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Medical History Apr 2023Guinea worm disease (dracunculiasis) is a debilitating waterborne disease. Once widespread, it is now on the brink of eradication. However, the Guinea Worm Eradication...
Guinea worm disease (dracunculiasis) is a debilitating waterborne disease. Once widespread, it is now on the brink of eradication. However, the Guinea Worm Eradication Programme (GWEP), like guinea worm itself, has been under-studied by historians. The GWEP demonstrates an unusual model of eradication, one focused on primary healthcare (PHC), community participation, health education and behavioural change (safe drinking). The PHC movement collided with a waterborne disease, which required rapid but straightforward treatment to prevent transmission, creating a historical space for the emergence of village-based volunteer health workers, as local actors realigned global health policy on a local level. These Village Volunteers placed eradication in the hands of residents of endemic areas, epitomising the participation-focused nature of the GWEP. This participatory mode of eradication highlights the agency of those in endemic areas, who, through volunteering, safe drinking and community self-help, have been the driving force behind dracunculiasis eradication. In the twenty-first century, guinea worm has become firstly a problem of human mobility, as global health has struggled to contain cases in refugees and nomads, and latterly a zoonotic disease, as guinea worm has shifted hosts to become primarily a parasite of dogs. This demonstrates both the potential of One Health approaches and the need for One Health to adopt from PHC and the GWEP a focus on the health of humans and animals in isolated and impoverished areas. Guinea worm demonstrates how the biological and the historical interact, with the GWEP and guinea worm shaping each other over the course of the eradication programme.
Topics: Humans; Animals; Dogs; Dracunculus Nematode; Dracunculiasis; Waterborne Diseases; Health Education; Health Policy; Disease Eradication
PubMed: 37525460
DOI: 10.1017/mdh.2023.18 -
Protein Science : a Publication of the... Sep 2023Nicotinic acetylcholine receptors (N-AChRs) mediate fast synaptic signaling and are members of the pentameric ligand-gated ion channel (pLGIC) family. They rely on a...
Nicotinic acetylcholine receptors (N-AChRs) mediate fast synaptic signaling and are members of the pentameric ligand-gated ion channel (pLGIC) family. They rely on a network of accessory proteins in vivo for correct formation and transport to the cell surface. Resistance to cholinesterase 3 (RIC-3) is an endoplasmic reticulum protein that physically interacts with nascent pLGIC subunits and promotes their oligomerization. It is not known why some N-AChRs require RIC-3 in heterologous expression systems, whereas others do not. Previously we reported that the ACR-16 N-AChR from the parasitic nematode Dracunculus medinensis does not require RIC-3 in Xenopus laevis oocytes. This is unusual because all other nematode ACR-16, like the closely related Ascaris suum ACR-16, require RIC-3. Their high sequence similarity limits the number of amino acids that may be responsible, and the goal of this study was to identify them. A series of chimeras and point mutations between A. suum and D. medinensis ACR-16, followed by functional characterization with electrophysiology, identified two residues that account for a majority of the receptor requirement for RIC-3. ACR-16 with R/K159 in the cys-loop and I504 in the C-terminal tail did not require RIC-3 for functional expression. Mutating either of these to R/K159E or I504T, residues found in other nematode ACR-16, conferred a RIC-3 requirement. Our results agree with previous studies showing that these regions interact and are involved in receptor synthesis. Although it is currently unclear what precise mechanism they regulate, these residues may be critical during specific subunit folding and/or assembly cascades that RIC-3 may promote.
Topics: Receptors, Nicotinic; Cholinesterases; Cell Membrane; Endoplasmic Reticulum
PubMed: 37417463
DOI: 10.1002/pro.4718 -
Le Infezioni in Medicina 2023Dracunculiasis (Guinea Worm Disease) is a terrible disease limited, even historically, to the arid and poor areas of our planet and which in the West has always been...
Dracunculiasis (Guinea Worm Disease) is a terrible disease limited, even historically, to the arid and poor areas of our planet and which in the West has always been seen as an exotic disease and therefore has never taken root in the collective imagination. This parasitosis is transmitted to humans by drinking water contaminated with crustacean harboring larvae of , a nematode. The natural history of the disease is caused by adult worms invading connective tissues and causing blistering, ulceration and edema. Well known in Ancient Egypt where the disease was endemic in its southern area, was known in Europe mainly from the reports of medical writers starting from the Roman imperial period but without direct knowledge. In Middle age the descriptions of this disease that physicians and surgeons could read on medical books, at the end, were attributed to veterinary parasitic disease. In Modern age only during the colonialist era dracunculiasis was perceived as a problem, however sporadic. In 1986 Guinea Worm Eradication Program (GWEP) was launch without success. Thus, the disappearance of this parasitosis should still be postponed but not abandoned.
PubMed: 37283632
DOI: 10.53854/liim-3102-15 -
MMWR. Morbidity and Mortality Weekly... Nov 2022Dracunculiasis (Guinea worm disease), caused by the parasite Dracunculus medinensis, is acquired by drinking water containing small crustacean copepods (water fleas)...
Dracunculiasis (Guinea worm disease), caused by the parasite Dracunculus medinensis, is acquired by drinking water containing small crustacean copepods (water fleas) infected with D. medinensis larvae. Recent evidence suggests that the parasite also appears to be transmitted by eating fish or other aquatic animals. About 1 year after infection, the worm typically emerges through the skin on a lower limb of the host, causing pain and disability (1). No vaccine or medicine is available to prevent or treat dracunculiasis. Eradication relies on case containment* to prevent water contamination and other interventions to prevent infection, including health education, water filtration, treatment of unsafe water with temephos (an organophosphate larvicide), and provision of safe drinking water (1,2). CDC began worldwide eradication efforts in October 1980, and in 1984 was designated by the World Health Organization (WHO) as the technical monitor of the Dracunculiasis Eradication Program (1). In 1986, with an estimated 3.5 million cases occurring annually in 20 African and Asian countries (3), the World Health Assembly called for dracunculiasis elimination. The Guinea Worm Eradication Program (GWEP), led by The Carter Center and supported by partners that include WHO, UNICEF, and CDC, began assisting ministries of health in countries with endemic disease. In 2021, a total of 15 human cases were identified and three were identified during January-June 2022. As of November 2022, dracunculiasis remained endemic in five countries (Angola, Chad, Ethiopia, Mali, and South Sudan); cases reported in Cameroon were likely imported from Chad. Eradication efforts in these countries are challenged by infection in animals, the COVID-19 pandemic, civil unrest, and insecurity. Animal infections, mostly in domestic dogs, some domestic cats, and in Ethiopia, a few baboons, have now surpassed human cases, with 863 reported animal infections in 2021 and 296 during January-June 2022. During the COVID-19 pandemic all national GWEPs remained fully operational, implementing precautions to ensure safety of program staff members and community members. In addition, the progress toward eradication and effectiveness of interventions were reviewed at the 2021 and 2022 annual meetings of GWEP program managers, and the 2021 meeting of WHO's International Commission for the Certification of Dracunculiasis Eradication. With only 15 human cases identified in 2021 and three during January-June 2022, program efforts appear to be closer to reaching the goal of eradication. However, dog infections and impeded access because of civil unrest and insecurity in Mali and South Sudan continue to be the greatest challenges for the program. This report describes progress during January 2021-June 2022 and updates previous reports (2,4).
Topics: Humans; Animals; Cats; Dogs; Dracunculiasis; Drinking Water; COVID-19; Pandemics; Disease Eradication
PubMed: 36417302
DOI: 10.15585/mmwr.mm7147a2 -
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 -
Tropical Medicine and Infectious Disease Nov 2022Dracunculiasis, also known as Guinea worm disease (GWD), is a neglected tropical disease (NTD) caused by a parasite (). In the past, dracunculiasis was known as "the... (Review)
Review
BACKGROUND
Dracunculiasis, also known as Guinea worm disease (GWD), is a neglected tropical disease (NTD) caused by a parasite (). In the past, dracunculiasis was known as "the disease of the empty granary" because of the difficulties patients had in going to work in fields or to school when affected by this disease. In tropical areas, the condition has been widespread in economically disadvantaged communities, and has been associated with reduced economic status and low levels of education.
METHODS
we searched PubMed, Scopus, Google Scholar, EMBASE, Cochrane Library, and WHO websites for literature addressing dracunculiasis published in the last 50 years.
RESULTS
by development and optimization of multi-layered control measures, transmission by the vector has been interrupted, but there are foci in several African countries with a high risk of compromising the results obtained in the control of this neglected disease.
CONCLUSION
this review features state-of-the-art data on the infection prevalence, geographical distribution, diagnostics, parasite-host interactions, and the pathology of dracunculiasis. Also described are the current state and future perspectives for vector control and elimination strategies.
PubMed: 36355908
DOI: 10.3390/tropicalmed7110366 -
PLoS Neglected Tropical Diseases Oct 2022Dracunculus medinensis (Guinea worm) is a parasitic nematode that can cause the debilitating disease dracunculiasis (Guinea worm disease) in humans. The global Guinea...
Dracunculus medinensis (Guinea worm) is a parasitic nematode that can cause the debilitating disease dracunculiasis (Guinea worm disease) in humans. The global Guinea Worm Eradication Program has led intervention and eradication efforts since the 1980s, and Guinea worm infections in people have decreased >99.99%. With the final goal of eradication drawing nearer, reports of animal infections from some remaining endemic countries pose unique challenges. Currently, confirmation of suspected Guinea worm infection relies on conventional molecular techniques such as polymerase chain reaction (PCR), which is not specific to Guinea worm and, therefore, requires sequencing of the PCR products to confirm the identity of suspect samples, a process that often takes a few weeks. To decrease the time required for species confirmation, we developed a quantitative PCR assay targeting the mitochondrial cytochrome b (cytb) gene of Guinea worm. Our assay has a limit of detection of 10 copies per reaction. The mean analytical parameters (± SE) were as follows: efficiency = 93.4 ± 7.7%, y-intercept = 40.93 ± 1.11, slope = -3.4896 ± 0.12, and the R2 = 0.999 ± 0.004. The assay did not amplify other nematodes found in Guinea worm-endemic regions and demonstrated 100% diagnostic sensitivity and specificity. Implementation of this quantitative PCR assay for Guinea worm identification could eliminate the need for DNA sequencing to confirm species. Thus, this approach can be implemented to provide more rapid confirmation of Guinea worm infections, leading to faster execution of Guinea worm interventions while increasing our understanding of infection patterns.
Topics: Humans; Animals; Dracunculus Nematode; Cytochromes b; Dracunculiasis; Polymerase Chain Reaction
PubMed: 36206300
DOI: 10.1371/journal.pntd.0010830 -
Veterinary Parasitology, Regional... Oct 2022Neglected tropical diseases pose a threat to domestic animal health, as domestic animals can serve as reservoirs for certain zoonotic parasitic infections, including...
Neglected tropical diseases pose a threat to domestic animal health, as domestic animals can serve as reservoirs for certain zoonotic parasitic infections, including Guinea worm (Dracunculus medinensis) and lymphatic filariasis. Surveillance for these parasites in domestic animals is needed to understand infection prevalence and transmission cycles, with the goal of instituting appropriate interventions. The goal of this research was to report our finding of Brugia sp. infection in dogs from Chad, Africa, and to characterize the genetics and epidemiology of the parasite. During a recent Chadian canine pathogen surveillance project, we identified Brugia sp. infections in a total of 46 out of 428 dogs (10.7%) sampled at three time points in 2019-2020. We found high levels of sequence similarity to B. malayi and B. pahangi based on amplification of 18S rRNA, 5.8S rRNA, and ITS-2 regions. Phylogenetic analysis of 18S rRNA gene sequences placed the Chadian Brugia sp. in a clade with other Brugia spp. but grouped it separately from both B. malayi and B. pahangi. Analysis of Hha I sequences showed the greatest similarity with B. patei, a parasite previously reported from dogs, cats, and wildlife hosts in Kenya. Epidemiologic analysis using generalized linear regression modeling found significantly higher odds of Brugia sp. detection among dogs in villages in southern Chad compared to those in the northern region. Further, within the northern region, there were higher odds of detection in the dry season, compared to the wet season, which is consistent with the ecology of a presumably mosquito-borne parasite. The same 428 dogs were tested for Dirofilaria immitis antigen using a commercial assay (IDEXX SNAP 4Dx) at the earliest time point of the study, with 119 dogs testing positive. However, no association was noted between Brugia infection and a dog being positive for Di. immitis antigen, with only seven of the 119 Di. immitis antigen-positive dogs being Brugia-positive. This is the first report of Brugia sp. in domestic dogs in Chad and additional research is needed to definitively identify the species present, elucidate transmission, and understand potential risks to canine and human health.
Topics: Animals; Brugia; Cat Diseases; Cats; Chad; Dog Diseases; Dogs; Dracunculus Nematode; Filariasis; Humans; Phylogeny; RNA, Ribosomal, 18S; RNA, Ribosomal, 5.8S; Zoonoses
PubMed: 36184112
DOI: 10.1016/j.vprsr.2022.100784 -
Journal of Infection in Developing... Aug 2022Guinea worm disease is caused by Dracunculus medinensis. Transmission of the disease depends on vectors (copepods). Abate applications in targeted water sources to...
INTRODUCTION
Guinea worm disease is caused by Dracunculus medinensis. Transmission of the disease depends on vectors (copepods). Abate applications in targeted water sources to control copepod is the main intervention. The aim of this study was to assess vector control practice in the guinea worm endemic region of Gambela, Ethiopia and to identify elimination gaps.
METHODOLOGY
Retrospective analysis of routine program data recorded from 2016 to 2020 was performed. Pre-and post-copepod test is conducted on water ponds to determine the density of copepods. Based on the copepod density, the chemical is applied accordingly. The five years data was obtained from Ethiopian public health institute electronic database with permission.
RESULTS
A total of 22,131 water ponds were treated during the past five years. Out of the total treated in 2020, 4,669/7,266 (64%) were found with > 9 Copepods during pre-copepod test. 130/7,266 (1.79%) of water ponds which were post-tested after Abate application failed the requirement of scoring ≤ 9 copepods. Of the 130 water ponds, 115 (88.5%) were observed during the transmission season (April to November). Abate application trend had increased by 28.9% during the 5 years period. According to the database, some of the largest water sources found in infection reporting villages missed their 28 days regular treatment schedule.
CONCLUSIONS
A single water source that has not been treated effectively could be a source of infection for both humans and animals. The practice of Abate application should be enhanced and monitored regularly. The documenting system should be improved for quality, timely information and action.
Topics: Animals; Dracunculus Nematode; Ethiopia; Humans; Retrospective Studies; Temefos; Water
PubMed: 36156498
DOI: 10.3855/jidc.15972