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Tropical Medicine & International... May 2017Global eradication of the guinea worm (Dracunculus medinensis) is near, although perhaps delayed a little by the discovery of a transmission cycle in dogs. It is...
Global eradication of the guinea worm (Dracunculus medinensis) is near, although perhaps delayed a little by the discovery of a transmission cycle in dogs. It is therefore an appropriate time to reflect on the severe impact of this infection on the life of the communities where it was endemic prior to the start of the global eradication programme in 1981. From 1971 to 1974, we conducted a series of unpublished studies on guinea worm in a group of villages in Katsina State, northern Nigeria, where the infection was highly endemic. These studies demonstrated the high rate of infection in affected communities, the frequent recurrence of the infection in some subjects and the long-standing disability that remained in some infected individuals. Immunological studies showed a high level of immediate hypersensitivity to adult worm and larval antigens but a downregulation of Th1-type T-cell responses to worm antigens. Freeing communities such as those described in this article from the scourge of guinea worm infection for good will be an important public health triumph.
Topics: Animals; Antigens; Cost of Illness; Disabled Persons; Dogs; Down-Regulation; Dracunculiasis; Dracunculus Nematode; Endemic Diseases; Humans; Hypersensitivity; Nigeria; Recurrence; Th1 Cells
PubMed: 28196301
DOI: 10.1111/tmi.12855 -
PLoS Neglected Tropical Diseases Oct 2018Following almost 10 years of no reported cases, Guinea worm disease (GWD or dracunculiasis) reemerged in Chad in 2010 with peculiar epidemiological patterns and...
Following almost 10 years of no reported cases, Guinea worm disease (GWD or dracunculiasis) reemerged in Chad in 2010 with peculiar epidemiological patterns and unprecedented prevalence of infection among non-human hosts, particularly domestic dogs. Since 2014, animal infections with Guinea worms have also been observed in the other three countries with endemic transmission (Ethiopia, Mali, and South Sudan), causing concern and generating interest in the parasites' true taxonomic identity and population genetics. We present the first extensive population genetic data for Guinea worm, investigating mitochondrial and microsatellite variation in adult female worms from both human and non-human hosts in the four endemic countries to elucidate the origins of Chad's current outbreak and possible host-specific differences between parasites. Genetic diversity of Chadian Guinea worms was considerably higher than that of the other three countries, even after controlling for sample size through rarefaction, and demographic analyses are consistent with a large, stable parasite population. Genealogical analyses eliminate the other three countries as possible sources of parasite reintroduction into Chad, and sequence divergence and distribution of genetic variation provide no evidence that parasites in human and non-human hosts are separate species or maintain isolated transmission cycles. Both among and within countries, geographic origin appears to have more influence on parasite population structure than host species. Guinea worm infection in non-human hosts has been occasionally reported throughout the history of the disease, particularly when elimination programs appear to be reaching their end goals. However, no previous reports have evaluated molecular support of the parasite species identity. Our data confirm that Guinea worms collected from non-human hosts in the remaining endemic countries of Africa are Dracunculus medinensis and that the same population of worms infects both humans and dogs in Chad. Our genetic data and the epidemiological evidence suggest that transmission in the Chadian context is currently being maintained by canine hosts.
Topics: Animals; Chad; DNA, Mitochondrial; Disease Transmission, Infectious; Dogs; Dracunculiasis; Dracunculus Nematode; Ethiopia; Female; Genetic Variation; Genetics, Population; Genotype; Genotyping Techniques; Humans; Mali; Microsatellite Repeats; Papio; Sudan
PubMed: 30286084
DOI: 10.1371/journal.pntd.0006747 -
Computational and Mathematical Methods... 2017Guinea worm disease (GWD) is both a neglected tropical disease and an environmentally driven infectious disease. Environmentally driven infectious diseases remain one of...
Guinea worm disease (GWD) is both a neglected tropical disease and an environmentally driven infectious disease. Environmentally driven infectious diseases remain one of the biggest health threats for human welfare in developing countries and the threat is increased by the looming danger of climate change. In this paper we present a multiscale model of GWD that integrates the within-host scale and the between-host scale. The model is used to concurrently examine the interactions between the three organisms that are implicated in natural cases of GWD transmission, the copepod vector, the human host, and the protozoan worm parasite , and identify their epidemiological roles. The results of the study (through sensitivity analysis of ) show that the most efficient elimination strategy for GWD at between-host scale is to give highest priority to copepod vector control by killing the copepods in drinking water (the intermediate host) by applying chemical treatments (e.g., temephos, an organophosphate). This strategy should be complemented by health education to ensure that greater numbers of individuals and communities adopt behavioural practices such as voluntary reporting of GWD cases, prevention of GWD patients from entering drinking water bodies, regular use of water from safe water sources, and, in the absence of such water sources, filtering or boiling water before drinking. Taking into account the fact that there is no drug or vaccine for GWD (interventions which operate at within-host scale), the results of our study show that the development of a drug that kills female worms at within-host scale would have the highest impact at this scale domain with possible population level benefits that include prevention of morbidity and prevention of transmission.
Topics: Animals; Climate Change; Copepoda; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Drinking Water; Female; Humans; Models, Biological
PubMed: 28808479
DOI: 10.1155/2017/1473287 -
International Journal For Parasitology.... Apr 2024The genus contains numerous species of subcutaneous parasites of mammals and reptiles. In North America, there are at least three mammal-infecting species of . Reports...
The genus contains numerous species of subcutaneous parasites of mammals and reptiles. In North America, there are at least three mammal-infecting species of . Reports of infections have been reported from river otters () since the early 1900s; however, little is known about the species infecting otters or their ecology. Most reports of do not have a definitive species identified because females, the most common sex found due to their larger size and location in the extremities of the host, lack distinguishing morphological characteristics, and few studies have used molecular methods to confirm identifications. Thus, outside of Ontario, Canada, where both and have been confirmed in otters, the species of in river otters is unknown. In the current study, molecular characterization of nematodes from river otters revealed a high diversity of species. In addition to confirming infections, two new clades were detected. One clade was a novel species in any host and the other was a clade previously detected in Virginia opossums () from the USA and a domestic dog from Spain. No infections with were detected and neither new lineage was genetically similar to , which was recently described from a neotropical otter () from Argentina. These data also indicate that spp. infections in otters are widespread throughout Eastern North America. Currently the life cycles for most of the spp. infecting otters are unknown. Studies on the diversity, life cycle, and natural history of Dracunculidae parasites in wildlife are important because the related parasite, (human Guinea worm) is the subject of an international eradication campaign and there are increasing reports of these parasites in new geographic locations and new hosts, including new species in humans and domestic dogs.
PubMed: 38516639
DOI: 10.1016/j.ijppaw.2024.100922 -
PLoS Neglected Tropical Diseases May 2020After a ten-year absence of reported Guinea worm disease in Chad, human cases were rediscovered in 2010, and canine cases were first recorded in 2012. In response,...
After a ten-year absence of reported Guinea worm disease in Chad, human cases were rediscovered in 2010, and canine cases were first recorded in 2012. In response, active surveillance for Guinea worm in both humans and animals was re-initiated in 2012. As of 2018, the Chad Guinea Worm Eradication Program (CGWEP) maintains an extensive surveillance system that operates in 1,895 villages, and collects information about worms, hosts (animals and humans), and animal owners. This report describes in detail the CGWEP surveillance system and explores epidemiological trends in canine Guinea worm cases during 2015-2018. Our results showed an increased in the number of canine cases detected by the system during the period of interest. The proportion of worms that were contained (i.e., water contamination was prevented) improved significantly over time, from 72.8% in 2015 to 85.7% in 2018 (Mantel-Haenszel chi-square = 253.3, P < 0.0001). Additionally, approximately 5% of owners of infected dogs reported that the dog had a Guinea worm-like infection earlier that year; 12.6% had a similar worm in a previous year. The proportion of dogs with a history of infection in a previous year increased over time (Mantel-Haenszel chi-square = 18.8, P < 0.0001). Canine cases were clustered in space and time: most infected dogs (80%) were from the Chari Baguirmi (38.1%) and Moyen Chari Regions (41.9%), and for each year the peak month of identified canine cases was June, with 78.5% occurring during March through August. Findings from this report evoke additional questions about why some dogs are repeatedly infected. Our results may help to target interventions and surveillance efforts in terms of space, time, and dogs susceptible to recurrent infection, with the ultimate goal of Guinea worm eradication.
Topics: Animals; Chad; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Epidemiological Monitoring; Female; Humans; Male
PubMed: 32463811
DOI: 10.1371/journal.pntd.0008207 -
MMWR. Morbidity and Mortality Weekly... Nov 2014Dracunculiasis (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 will emerge through the skin, usually on the lower limb. Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. In 1986, the World Health Assembly called for dracunculiasis elimination. The global Guinea Worm Eradication Program, supported by The Carter Center, World Health Organization (WHO), UNICEF, CDC, and other partners, began assisting ministries of health of countries in which dracunculiasis is endemic in meeting this goal. At that time, an estimated 3.5 million cases occurred each year in 20 countries in Africa and Asia. This report updates published (3-5) and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication. A total of 148 cases were reported in 2013 from five countries (in order of prevalence: South Sudan, Chad, Mali, Ethiopia, and Sudan) compared with 542 cases in 2012 from four countries (South Sudan, Chad, Mali, and Ethiopia). The disease remains endemic in four countries in 2014 (South Sudan, Chad, Mali, and Ethiopia), but the overall incidence is falling faster in 2013 compared with 2012 (by 73%) and continues to fall faster in the first 6 months of 2014 (by 71%) compared with the same period in 2013. Failures in surveillance and containment, lack of clean drinking water, insecurity in Mali and parts of South Sudan, and an unusual epidemiologic pattern in Chad are the main remaining challenges to dracunculiasis eradication.
Topics: Africa; Disease Eradication; Dracunculiasis; Global Health; Humans; Incidence; Population Surveillance; Social Conditions; Water Supply
PubMed: 25412061
DOI: No ID Found -
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 -
The American Journal of Tropical... Aug 2015Thirty-seven unusual specimens, three from Ethiopia and 34 from South Sudan, were submitted since 2012 for further identification by the Ethiopian Dracunculiasis...
Thirty-seven unusual specimens, three from Ethiopia and 34 from South Sudan, were submitted since 2012 for further identification by the Ethiopian Dracunculiasis Eradication Program (EDEP) and the South Sudan Guinea Worm Eradication Program (SSGWEP), respectively. Although the majority of specimens emerged from sores or breaks in the skin, there was concern that they did not represent bona fide cases of Dracunculus medinensis and that they needed detailed examination and identification as provided by the World Health Organization Collaborating Center (WHO CC) at Centers for Disease Control and Prevention (CDC). All 37 specimens were identified on microscopic study as larval tapeworms of the spargana type, and DNA sequence analysis of seven confirmed the identification of Spirometra sp. Age of cases ranged between 7 and 70 years (mean 25 years); 21 (57%) patients were male and 16 were female. The presence of spargana in open skin lesions is somewhat atypical, but does confirm the fact that populations living in these remote areas are either ingesting infected copepods in unsafe drinking water or, more likely, eating poorly cooked paratenic hosts harboring the parasite.
Topics: Adolescent; Adult; Aged; Animals; Child; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Ethiopia; Female; Food Contamination; Food Parasitology; Foodborne Diseases; Humans; Larva; Male; Middle Aged; Sparganosis; Specimen Handling; Spirometra; Sudan; Water Supply; Young Adult
PubMed: 26055739
DOI: 10.4269/ajtmh.15-0236 -
The National Medical Journal of India 2019Dracunculiasis or guinea-worm infection is a water-borne, parasitic disease that can cause major morbidity. Dracunculiasis in patients with diabetes can be misdiagnosed...
Dracunculiasis or guinea-worm infection is a water-borne, parasitic disease that can cause major morbidity. Dracunculiasis in patients with diabetes can be misdiagnosed as a diabetic foot abscess, which is a common complication of poorly controlled diabetes. This is a report of guinea-worm disease (GWD) in a 57-year-old man with diabetes from a rural area of Kerala. There is need for awareness among physicians about the occurrence of GWD in people with diabetes and the need to ensure supply of safe drinking water to prevent its re- emergence. Though WHO has declared India free of GWD, a few cases have been reported from the country.
Topics: Abscess; Animals; Diabetes Mellitus, Type 2; Diabetic Foot; Diagnosis, Differential; Dracunculiasis; Dracunculus Nematode; Drinking Water; Foot; Humans; India; Male; Middle Aged
PubMed: 31823935
DOI: 10.4103/0970-258X.272111 -
The American Journal of Tropical... Dec 2020The success of the Guinea Worm (GW) Eradication Program over the past three decades has been tempered by the persistence of GW disease in a few African nations and the...
The success of the Guinea Worm (GW) Eradication Program over the past three decades has been tempered by the persistence of GW disease in a few African nations and the potential for a future resurgence in cases. Domestic dogs are now a major concern as a disease reservoir as large numbers of cases of canine GW disease are now reported each year, mainly along the Chari River in Chad. As a first step toward the development of a serologic assay for dogs, archived human plasma samples from dracunculiasis-positive donors from Togo were used to select adult female GW antigens for peptide sequencing and cloning. Eight protein sequences of interest were expressed as recombinant glutathione--transferase (GST) fusion proteins, and the most promising proteins were coupled to carboxylated microspheres for use in multiplex assays. A thioredoxin-like protein (TRXL1) and a domain of unknown function (DUF148) were assessed for total IgG and IgG reactivities using a panel of specimens from GW cases, uninfected donors, and individuals infected with various nematode worms, including . Both the DUF148-GST and the TRXL1-GST assays cross-reacted with sera, but the latter assay was always the more specific. The IgG and total IgG TRXL1-GST assays both had sensitivities > 87% and specificities > 90%. Maximum specificity (> 96%) was obtained with the total IgG assay when reactivity to both antigens was used to define a positive case. Given the good performance of the human assay, we are now working to modify the assay for dog assessments.
Topics: Animals; Antibodies, Helminth; Antigens, Helminth; Blotting, Western; Cross Reactions; Disease Eradication; Disease Reservoirs; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Electrophoresis, Polyacrylamide Gel; Glutathione Transferase; Humans; Immunoglobulin G; Onchocerca volvulus; Onchocerciasis; Recombinant Fusion Proteins; Sensitivity and Specificity; Serologic Tests; Thioredoxins
PubMed: 32901602
DOI: 10.4269/ajtmh.20-0511