-
Current Biology : CB Feb 2022Exploitation of natural resources is a driver of human infectious disease emergence. The emergence of animal reservoirs of Guinea worm Dracunculus medinensis,...
Exploitation of natural resources is a driver of human infectious disease emergence. The emergence of animal reservoirs of Guinea worm Dracunculus medinensis, particularly in domestic dogs Canis familiaris, has become the major impediment to global eradication of this human disease. 93% of all Guinea worms detected worldwide in 2020 were in dogs in Chad. Novel, non-classical pathways for transmission of Guinea worm in dogs, involving consumption of fish, have been hypothesized to support the maintenance of this animal reservoir. We quantified and analyzed variation in Guinea worm emergence in dogs in Chad, across three climatic seasons, in multiple villages and districts. We applied forensic stable isotope analyses to quantify dietary variation within and among dogs and GPS tracking to characterize their spatial ecology. At the end of the hot-dry season and beginning of the wet season, when fishing by people is most intensive, Guinea worm emergence rates in dogs were highest, dogs ate most fish, and fish consumption was most closely associated with disease. Consumption of fish by dogs enables a non-classical transmission pathway for Guinea worm in Chad. Seasonal fisheries and the facilitation of dogs eating fish are likely contributing to disease persistence and to this key impediment to human disease eradication. Interrelated natural resource use, climatic variation, companion animal ecology, and human health highlight the indispensability of One Health approaches to the challenges of eradicating Guinea worm and other zoonotic diseases.
Topics: Animals; Dogs; Dracunculiasis; Dracunculus Nematode; Fisheries; Humans; Seasons; Zoonoses
PubMed: 34910949
DOI: 10.1016/j.cub.2021.11.050 -
Releve Epidemiologique Hebdomadaire May 2017
Topics: Africa; Animals; Civil Disorders; Disease Eradication; Dog Diseases; Dogs; Dracunculiasis; Endemic Diseases; Global Health; Humans; Population Surveillance
PubMed: 28530374
DOI: No ID Found -
Bulletin of the World Health... Dec 2014Conflict and a new disease pattern are hampering efforts to eradicate guinea-worm disease in the last four endemic countries. Julius Cavendish reports.
Conflict and a new disease pattern are hampering efforts to eradicate guinea-worm disease in the last four endemic countries. Julius Cavendish reports.
Topics: Chad; Disease Eradication; Dracunculiasis; Ethiopia; Health Education; Humans; Mali; Sanitation; Sudan; World Health Organization
PubMed: 25552768
DOI: 10.2471/BLT.14.021214 -
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 -
Indian Journal of Dermatology,... 2023A nematode parasite, Dracunculus medinensis, causes dracunculiasis. Despite being non-fatal, this condition causes significant morbidity. Dracunculiasis is considered an...
A nematode parasite, Dracunculus medinensis, causes dracunculiasis. Despite being non-fatal, this condition causes significant morbidity. Dracunculiasis is considered an eradicated disease in India since 1999. We report two cases that document the unusual linear morphea-like morphology of the calcified D. medinensis and the rare periorbital location of the worm. The cases presented here are rare and a diagnostic challenge, considering the eradicated status of dracunculiasis.
Topics: Animals; Humans; Dracunculiasis; Dracunculus Nematode; India; Skin Diseases
PubMed: 33969654
DOI: 10.25259/IJDVL_909_20 -
The Lancet. Microbe Feb 2022Dracunculiasis (also known as Guinea worm disease), caused by the Dracunculus medinensis nematode, is progressing towards eradication, with a reduction in cases from...
BACKGROUND
Dracunculiasis (also known as Guinea worm disease), caused by the Dracunculus medinensis nematode, is progressing towards eradication, with a reduction in cases from 3·5 million cases in the mid-1980s to only 54 human cases at the end of 2019. Most cases now occur in Chad. On April 19, 2019, a 19-year-old woman presented with D medinensis in an area within the Salamat region of Chad, where the disease had not been previously reported. We aimed to investigate the connection between this case and others detected locally and elsewhere in Chad using a combination of epidemiological and genetic approaches.
METHODS
In this cross-sectional field study, we conducted household case searches and informal group interviews in the Bogam, Liwi, and Tarh villages in Chad. All community members including children were eligible for participation in the outbreak investigation. Adult female D medinensis associated with this outbreak were collected for genetic analysis (18 from humans and two from dogs). Four mitochondrial genes and 22 nuclear microsatellite markers were used to assess relatedness of worms associated with the outbreak in comparison with other worms from elsewhere in Chad.
FINDINGS
Between April 12 and Sept 6, 2019, we identified 22 human cases and two canine cases of dracunculiasis associated with 15 households. Six (40%) of the 15 affected households had multiple human or canine cases within the household. Most cases of dracunculiasis in people were from three villages in Salamat (21 [95%] of 22 cases), but one case was detected nearly 400 km away in Sarh city (outside the Salamat region). All people with dracunculiasis reported a history of consuming fish and unfiltered water. Worms associated with this outbreak were genetically similar and shared the same maternal lineage.
INTERPRETATION
Molecular epidemiological results suggest a point-source outbreak that originated from a single female D medinensis, rather than newly identified sustained local transmission. The failure of the surveillance system to detect the suspected canine infection in 2018 highlights the challenge of canine D medinensis detection, particularly in areas under passive surveillance. Human movement can also contribute to dracunculiasis spread over long distances.
FUNDING
The Carter Center.
Topics: Animals; Chad; Cross-Sectional Studies; Disease Outbreaks; Dogs; Dracunculiasis; Dracunculus Nematode; Female; Humans
PubMed: 35544041
DOI: 10.1016/S2666-5247(21)00209-3 -
MMWR. Morbidity and Mortality Weekly... Jun 2011Transmission of dracunculiasis (Guinea worm disease), a waterborne, parasitic disease targeted for eradication, was thought to have been interrupted in Chad since 2000,...
Transmission of dracunculiasis (Guinea worm disease), a waterborne, parasitic disease targeted for eradication, was thought to have been interrupted in Chad since 2000, when the last case was reported. However, in 2010, 10 cases were confirmed by the Chad Ministry of Public Health (Ministère de la Santé Publique [MSP]) and the World Health Organization (WHO) during field investigations in which rumored cases were investigated and nearby villages were actively searched for additional cases. Because patients were not prevented from contaminating water sources, new cases were expected in 2011. During January-February 2011, MSP, WHO, and CDC conducted an investigation to gather additional information to guide prevention and response activities before the 2011 transmission season. Seven districts where cases had been confirmed or suspected in 2010 or where dracunculiasis was endemic during 1994-2000 were surveyed. The results of those surveys indicated that residents of 116 (55%) of 210 villages and 13 (87%) of 15 nomad camps consumed water from unsafe sources; 157 (75%) of 209 village key informants (KIs) and five (33%) of 15 nomad camp KIs knew about dracunculiasis. Thirty-one villages had confirmed or suspected cases during 2009-2011 and were classified as at-risk, requiring weekly active surveillance and urgent pre-positioning of materials for the 2011 transmission season. Nomadic populations are at risk for dracunculiasis because of unsafe water consumption and minimal knowledge of the disease. These populations also require targeted surveillance and prevention efforts (e.g., filter distribution, education, and case containment) to interrupt dracunculiasis transmission .
Topics: Animals; Chad; Copepoda; Disease Outbreaks; Dracunculiasis; Dracunculus Nematode; Emigration and Immigration; Health Knowledge, Attitudes, Practice; Humans; Hygiene; Polymerase Chain Reaction; Population Surveillance; Water Purification; Water Supply
PubMed: 21659983
DOI: No ID Found -
PLoS Neglected Tropical Diseases Sep 2020Few human infectious diseases have been driven as close to eradication as dracunculiasis, caused by the Guinea worm parasite (Dracunculus medinensis). The number of...
Few human infectious diseases have been driven as close to eradication as dracunculiasis, caused by the Guinea worm parasite (Dracunculus medinensis). The number of human cases of Guinea worm decreased from an estimated 3.5 million in 1986 to mere hundreds by the 2010s. In Chad, domestic dogs were diagnosed with Guinea worm for the first time in 2012, and the numbers of infected dogs have increased annually. The presence of the parasite in a non-human host now challenges efforts to eradicate D. medinensis, making it critical to understand the factors that correlate with infection in dogs. In this study, we evaluated anthropogenic and environmental factors most predictive of detection of D. medinensis infection in domestic dog populations in Chad. Using boosted regression tree models to identify covariates of importance for predicting D. medinensis infection at the village and spatial hotspot levels, while controlling for surveillance intensity, we found that the presence of infection in a village was predicted by a combination of demographic (e.g. fishing village identity, dog population size), geographic (e.g. local variation in elevation), and climatic (e.g. precipitation and temperature) factors, which differed between northern and southern villages. In contrast, the presence of a village in a spatial infection hotspot, was primarily predicted by geography and climate. Our findings suggest that factors intrinsic to individual villages are highly predictive of the detection of Guinea worm parasite presence, whereas village membership in a spatial infection hotspot is largely determined by location and climate. This study provides new insight into the landscape-scale epidemiology of a debilitating parasite and can be used to more effectively target ongoing research and possibly eradication and control efforts.
Topics: Animals; Chad; Climate; Disease Eradication; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Geography; Machine Learning
PubMed: 32925916
DOI: 10.1371/journal.pntd.0008620 -
MMWR. Morbidity and Mortality Weekly... Mar 1995The plan for the global eradication of dracunculiasis (i.e., Guinea worm disease) was developed in October 1980 (1). Since 1987-1988, Global 2000, Inc., the United...
The plan for the global eradication of dracunculiasis (i.e., Guinea worm disease) was developed in October 1980 (1). Since 1987-1988, Global 2000, Inc., the United Nations Children's Fund (UNICEF), and the U.S. Agency for International Development have assisted the Guinea Worm Eradication Programs in Ghana and Nigeria, countries in west Africa. In 1989, Ghana and Nigeria ranked first and second in the number of reported cases of dracunculiasis with 179,556 and 640,008 cases, respectively (2). This report summarizes data for the two countries during 1994 and describes efforts toward eradication of dracunculiasis.
Topics: Dracunculiasis; Ghana; Humans; Nigeria
PubMed: 7870023
DOI: No ID Found -
Clinical Microbiology and Infection :... Nov 2012Thanks to improved health standards in Iran over the past three decades, we have witnessed a shift in the causes of death in Iran from infectious causes to... (Review)
Review
Thanks to improved health standards in Iran over the past three decades, we have witnessed a shift in the causes of death in Iran from infectious causes to non-communicable diseases-mainly cardiovascular disorders, cancers, and road traffic injuries. The incidence and prevalence of many infectious diseases, such as many parasitic infections, have fallen significantly; there have been no reported cases of dracunculiasis in Iran since the mid-1970s. Great strides have also been made towards the elimination of schistosomiasis in Iran. However, we still have some problems with cutaneous leishmaniasis, hepatitis C, human immunodeficiency virus, tuberculosis, infections among immunocompromised hosts, hospital-acquired infections, and antibiotic-resistant bacterial strains. We need to emphasize improvements in sanitation, good clinical practice, and education about the rational administration of antibiotics.
Topics: Communicable Disease Control; Communicable Diseases; Cross Infection; Drug Resistance, Bacterial; Humans; Iran
PubMed: 23033964
DOI: 10.1111/1469-0691.12021