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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 -
Journal of Biological Dynamics Dec 2018Global eradication of Guinea worm disease (GWD) is in the final stage but a mysterious epidemic of the parasite in dog population makes the elimination programme...
Global eradication of Guinea worm disease (GWD) is in the final stage but a mysterious epidemic of the parasite in dog population makes the elimination programme challenging. There is neither a vaccine nor an effective treatment against the disease and therefore intervention strategies rely on the current epidemiological understandings to control the spread of the disease. A novel mathematical model can predict the future outbreaks and it can quantify the dissemination rates of control interventions. Due to the lack of such novel models, a realistic mathematical model of GWD dynamics with human population, dog population, copepod population and the worm larvae is proposed and analyzed. Considering case data from Chad, we calibrate the model and perform global sensitivity analysis of the basic reproduction number with respect to the control parameters and copepod consumption rates. Furthermore, we investigate the impact of three control interventions: awareness of humans, isolation of infected dogs and copepod clearance from contaminated water sources. We also address the impact of combination interventions which leads to the conclusion that the combination of isolating the infected dogs and treating the contaminated ponds is a plausible way for eliminating the burden of GWD from Chad.
Topics: Animals; Chad; Dogs; Dracunculiasis; Dracunculus Nematode; Humans; Models, Biological
PubMed: 30325272
DOI: 10.1080/17513758.2018.1529829 -
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 -
Gates Open Research Jun 2018The objective of this study was to document the worldwide decline of dracunculiasis (Guinea worm disease, GWD) burden, expressed as disability-adjusted life years...
The objective of this study was to document the worldwide decline of dracunculiasis (Guinea worm disease, GWD) burden, expressed as disability-adjusted life years (DALYs), from 1990 to 2016, as estimated in the Global Burden of Disease study 2016 (GBD 2016). While the annual number of cases of GWD have been consistently reported by WHO since the 1990s, the burden of disability due to GWD has not previously been quantified in GBD. The incidence of GWD was modeled for each endemic country using annual national case reports. A literature search was conducted to characterize the presentation of GWD, translate the clinical symptoms into health sequelae, and then assign an average duration to the infection. Prevalence measures by sequelae were multiplied by disability weights to estimate DALYs. The total DALYs attributed to GWD across all endemic countries (n=21) in 1990 was 50,725 (95% UI: 35,265-69,197) and decreased to 0.9 (95% UI: 0.5-1.4) in 2016. A cumulative total of 12,900 DALYs were attributable to GWD from 1990 to 2016. Using 1990 estimates of burden propagated forward, this analysis suggests that between 990,000 to 1.9 million DALYs have been averted as a result of the eradication program over the past 27 years.
PubMed: 30234196
DOI: 10.12688/gatesopenres.12827.1 -
The Lancet. Infectious Diseases Aug 2018
Topics: Animals; Communicable Disease Control; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Global Health; Humans; Public Health Surveillance; World Health Organization
PubMed: 30064676
DOI: 10.1016/S1473-3099(18)30437-7 -
The American Journal of Tropical... Aug 2018This report summarizes the status of the global Dracunculiasis Eradication Program as of the end of 2017. Dracunculiasis (guinea worm disease) has been eliminated from...
This report summarizes the status of the global Dracunculiasis Eradication Program as of the end of 2017. Dracunculiasis (guinea worm disease) has been eliminated from 19 of 21 countries where it was endemic in 1986, when an estimated 3.5 million cases occurred worldwide. Only Chad and Ethiopia reported cases in humans, 15 each, in 2017. Infections of animals, mostly domestic dogs, with were reported in those two countries and also in Mali. Insecurity and infections in animals are the two main obstacles remaining to interrupting dracunculiasis transmission completely.
Topics: Animals; Chad; Disease Eradication; Dogs; Dracunculiasis; Dracunculus Nematode; Epidemiological Monitoring; Ethiopia; Female; Global Health; Humans; Male; Water Supply
PubMed: 29869608
DOI: 10.4269/ajtmh.18-0204 -
Advances in Parasitology 2018By 2050 our civilized planet may be comprised predominantly of networked megacities embedded in warm subtropical and tropical climates, and under stress from climate...
By 2050 our civilized planet may be comprised predominantly of networked megacities embedded in warm subtropical and tropical climates, and under stress from climate change and catastrophic weather events. Urban slum areas in these cities, including those found in wealthier middle- and high-income nations (blue marble health), will be especially vulnerable to disease. Moreover, regional conflicts fought over shifting and limited resources, including water, will collapse health systems infrastructures to further promote disease emergence and reemergence. Thus while by 2050 we might congratulate ourselves for successfully eliminating some key parasitic and neglected tropical diseases such as dracunculiasis, lymphatic filariasis, onchocerciasis, and human African trypanosomiasis, there could be a commensurate rise in other parasitic diseases based on the scenarios highlighted above. Of particular concern are urban and newly urbanized helminth infections, including schistosomiasis and some soil-transmitted helminth infections, as well zoonotic helminthiases, such as toxocariasis, food-borne trematodiases, and cysticercosis. Protozoan infections persisting in urban environments, including leishmaniasis, Chagas disease, malaria, and intestinal protozoan infections, will also remain, as will zoonotic diseases such as toxoplasmosis. Our best hope to counteract the parasitic diseases emerging in our steaming 21st century megacities is to develop new and innovative technologies through gene editing, systems biology, and immunology, and the new single-celled OMICs. However, success on this front will require our ability to contain the globalization of antiscience beliefs and sentiments.
Topics: Animals; Climate Change; Forecasting; Global Health; Humans; Parasitic Diseases; Risk Factors
PubMed: 29753341
DOI: 10.1016/bs.apar.2018.03.002 -
The American Journal of Tropical... May 2018
Topics: Adult; Animals; Calcinosis; Dracunculiasis; Dracunculus Nematode; Female; Humans; Radiography
PubMed: 29745364
DOI: 10.4269/ajtmh.17-0944 -
Clinical Infectious Diseases : An... Jul 2018Neglected tropical diseases affect >1 billion of the world's poorest persons. Control programs range from near-elimination (dracunculiasis) to increasing prevalence...
Neglected tropical diseases affect >1 billion of the world's poorest persons. Control programs range from near-elimination (dracunculiasis) to increasing prevalence (dengue and cutaneous leishmaniasis). These are some of the most cost-effective public health interventions and should be a global priority.
Topics: Disease Eradication; Global Health; Humans; Neglected Diseases; Poverty; Prevalence; Tropical Medicine; World Health Organization
PubMed: 29688342
DOI: 10.1093/cid/ciy349 -
The American Journal of Tropical... May 2018Despite several periods of stagnating guinea worm disease (GWD) incidence in Ghana during its national eradication campaign in the 1990s and early 2000s, the last...
Despite several periods of stagnating guinea worm disease (GWD) incidence in Ghana during its national eradication campaign in the 1990s and early 2000s, the last reported case of GWD was in May 2010. In July 2011, Ghana celebrated the interruption of guinea worm (GW) transmission. Although it has been established that GWD causes disability, pain, and socioeconomic hardship, there is a dearth of population-based evidence collected in post-GW-endemic countries to document the value attributed to GWD eradication by residents in formerly endemic communities. Given Ghana's recent history of GWD and a concentrated burden of the disease in its Northern Region, a pattern which remained true through to the final stage of the eradication campaign, seven villages in the Northern Region were targeted for a retrospective, cross-sectional study to detail the perceptions, attitudes, and beliefs about the impact of eradication of GWD in northern Ghana. The study revealed that respondents from the sampled communities felt GW eradication improved their socioeconomic conditions, as the impact of infection prohibited the pursuit of individual and social advancement. The value residents placed on the absence of GWD highlights both the impact infection had on the pursuit of social and economic advancement and the newfound ability to be disease-free and productive. Of the 143 respondents, 133 had GWD in the past and were incapacitated for an average of 6 weeks annually per GW infection, with each infected person affected nearly four times in his or her lifetime.
Topics: Adolescent; Adult; Animals; Cross-Sectional Studies; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Female; Ghana; Humans; Male; Middle Aged; Retrospective Studies; Young Adult
PubMed: 29557333
DOI: 10.4269/ajtmh.17-0558