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MMWR. Morbidity and Mortality Weekly... Oct 2011In 1986, the World Health Assembly (WHA) called for the elimination of dracunculiasis (Guinea worm disease), a parasitic infection in humans caused by Dracunculus...
In 1986, the World Health Assembly (WHA) called for the elimination of dracunculiasis (Guinea worm disease), a parasitic infection in humans caused by Dracunculus medinensis. At the time, an estimated 3.5 million cases were occurring annually in 20 countries in Africa and Asia, and 120 million persons were at risk for the disease. Because of slow mobilization in countries with endemic disease, the 1991 WHA goal to eradicate dracunculiasis globally by 1995 was not achieved. In 2004, WHA established a new target date of 2009 for global eradication; despite considerable progress, that target date also was not met. This report updates published and previously unpublished data and describes progress towards global eradication of dracunculiasis since January 2010. The number of indigenous cases of dracunculiasis worldwide decreased 44%, from 3,185 cases in 2009 to 1,793 in 2010. As of June 2011, dracunculiasis remained endemic in three countries (Ethiopia, Mali, and South Sudan). Of the 814 cases that occurred during January-June 2011, a total of 801 (98%) were reported from 358 villages in South Sudan. By October 2010, Ghana had gone 12 months without an indigenous case, thereby interrupting transmission; Ethiopia and Mali are close to interrupting transmission, as indicated by the small and declining numbers of cases in these two countries. An outbreak of 10 cases was discovered in Chad in 2010. The current target is to interrupt transmission in the remaining countries as soon as possible. Insecurity (e.g., sporadic violence or civil unrest) in areas of South Sudan and Mali, where dracunculiasis is endemic, poses the greatest threat to the success of the global dracunculiasis eradication campaign.
Topics: Africa; Animals; Disease Eradication; Disease Outbreaks; Dracunculiasis; Dracunculus Nematode; Humans; Population Surveillance; Water Purification; Water Supply; World Health Organization
PubMed: 22031217
DOI: No ID Found -
MMWR. Morbidity and Mortality Weekly... Oct 2010In 1986, the World Health Assembly (WHA) called for the elimination of dracunculiasis (Guinea worm disease), a parasitic infection in humans caused by Dracunculus...
In 1986, the World Health Assembly (WHA) called for the elimination of dracunculiasis (Guinea worm disease), a parasitic infection in humans caused by Dracunculus medinensis. At the time, an estimated 3.5 million cases were occurring annually in 20 countries in Africa and Asia, and 120 million persons were at risk for the disease. Because of slow mobilization in countries with endemic disease, the 1991 WHA goal to eradicate dracunculiasis globally by 1995 was not achieved. In 2004, WHA established a new target date of 2009 for global eradication; despite considerable progress, that target date also was not met. This report updates both published and previously unpublished data and updates progress toward global eradication of dracunculiasis since January 2009. At the end of December 2009, dracunculiasis remained endemic in four countries (Ethiopia, Ghana, Mali, and Sudan). The number of indigenous cases of dracunculiasis worldwide had decreased 31%, from 4,613 in 2008 to 3,185 in 2009. Of the 766 cases that occurred during January--June 2010, a total of 745 (97%) were reported from 380 villages in Sudan. Ghana, Ethiopia, and Mali each are close to interrupting transmission, as indicated by the small and declining number of cases. The current target is to complete eradication in all four countries as quickly as possible. Insecurity (e.g., sporadic violence or civil unrest) in areas of Sudan and Mali where dracunculiasis is endemic poses the greatest threat to the success of the global dracunculiasis eradication program.
Topics: Africa; Dracunculiasis; Humans; Incidence; Population Surveillance; Social Conditions; Water Supply; World Health Organization
PubMed: 20881936
DOI: No ID Found -
PLoS Neglected Tropical Diseases Jul 2021Guinea worm (Dracunculus medinensis) was detected in Chad in 2010 after a supposed ten-year absence, posing a challenge to the global eradication effort. Initiation of a...
BACKGROUND
Guinea worm (Dracunculus medinensis) was detected in Chad in 2010 after a supposed ten-year absence, posing a challenge to the global eradication effort. Initiation of a village-based surveillance system in 2012 revealed a substantial number of dogs infected with Guinea worm, raising questions about paratenic hosts and cross-species transmission.
METHODOLOGY/PRINCIPAL FINDINGS
We coupled genomic and surveillance case data from 2012-2018 to investigate the modes of transmission between dog and human hosts and the geographic connectivity of worms. Eighty-six variants across four genes in the mitochondrial genome identified 41 genetically distinct worm genotypes. Spatiotemporal modeling revealed worms with the same genotype ('genetically identical') were within a median range of 18.6 kilometers of each other, but largely within approximately 50 kilometers. Genetically identical worms varied in their degree of spatial clustering, suggesting there may be different factors that favor or constrain transmission. Each worm was surrounded by five to ten genetically distinct worms within a 50 kilometer radius. As expected, we observed a change in the genetic similarity distribution between pairs of worms using variants across the complete mitochondrial genome in an independent population.
CONCLUSIONS/SIGNIFICANCE
In the largest study linking genetic and surveillance data to date of Guinea worm cases in Chad, we show genetic identity and modeling can facilitate the understanding of local transmission. The co-occurrence of genetically non-identical worms in quantitatively identified transmission ranges highlights the necessity for genomic tools to link cases. The improved discrimination between pairs of worms from variants identified across the complete mitochondrial genome suggests that expanding the number of genomic markers could link cases at a finer scale. These results suggest that scaling up genomic surveillance for Guinea worm may provide additional value for programmatic decision-making critical for monitoring cases and intervention efficacy to achieve elimination.
Topics: Animals; Chad; DNA, Helminth; Dracunculiasis; Dracunculus Nematode; Genetic Markers; Genome, Helminth; Genome, Mitochondrial; Humans; Population Surveillance
PubMed: 34310598
DOI: 10.1371/journal.pntd.0009609 -
Scientific Reports Jun 2021Dracunculus spp. are parasitic nematodes that infect numerous species of mammals and reptiles. The life cycles of Dracunculus species are complex, and unknowns remain...
Dracunculus spp. are parasitic nematodes that infect numerous species of mammals and reptiles. The life cycles of Dracunculus species are complex, and unknowns remain regarding the role of paratenic and transport hosts in transmission to definitive hosts. We had two primary objectives: to assess the susceptibility of several species of anurans, lizards, and fish as paratenic hosts for Dracunculus species, and to determine the long-term persistence of Dracunculus infections in African clawed frogs (Xenopus laevis). Animals were orally exposed to copepods infected with infectious third-stage larvae (L3s) of either Dracunculus insignis or D. medinensis. Dracunculus L3s were recovered from four anuran species, two lizard species, and one fish species, demonstrating that Dracunculus can infect tissues of a diversity of species. In long-term persistence trials, D. medinensis L3s were recovered from African clawed frogs tissues up to 58 days post-infection, and D. insignis L3s were recovered up to 244 days post-infection. Our findings regarding the susceptibility of novel species of frogs, lizards, and fish to infection with Dracunculus nematodes, and long-term persistence of L3s in paratenic hosts, address pressing knowledge gaps regarding Dracunculus infection in paratenic hosts and may guide future research regarding the transmission of Dracunculus to definitive mammalian hosts.
Topics: Animal Diseases; Animals; Anura; Dracunculiasis; Dracunculus Nematode; Fishes; Host-Parasite Interactions; Larva; Lizards
PubMed: 34083638
DOI: 10.1038/s41598-021-91122-5 -
Releve Epidemiologique Hebdomadaire Apr 2004
Topics: Africa; Disease Outbreaks; Dracunculiasis; Humans; World Health Organization
PubMed: 15139173
DOI: No ID Found -
Tropical Medicine & International... Dec 2009
Topics: Africa; Cuba; Dracunculiasis; Humans; India; Iran; Pakistan; Saudi Arabia; Uzbekistan; World Health Organization; Yemen
PubMed: 19788719
DOI: 10.1111/j.1365-3156.2009.02393.x -
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 -
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 -
Indian Journal of Dermatology,... 2023
PubMed: 37317714
DOI: 10.25259/IJDVL_909_20_RT -
Annals of Medicine and Surgery (2012) May 2023
PubMed: 37229012
DOI: 10.1097/MS9.0000000000000670