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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 -
Emerging Infectious Diseases Sep 2017To inform Dracunculus medinensis (Guinea worm) eradication efforts, we evaluated the role of fish as transport hosts for Dracunculus worms. Ferrets fed fish that had...
To inform Dracunculus medinensis (Guinea worm) eradication efforts, we evaluated the role of fish as transport hosts for Dracunculus worms. Ferrets fed fish that had ingested infected copepods became infected, highlighting the importance of recommendations to cook fish, bury entrails, and prevent dogs from consuming raw fish and entrails.
Topics: Animals; Chad; Copepoda; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Ferrets; Fish Diseases; Fishes; Food Chain; Host Specificity; Humans; Larva
PubMed: 28820381
DOI: 10.3201/eid2309.161931 -
Ethiopian Medical Journal 2017Dracunculiasis, also named Guinea Worm Disease (GWD), is one of the Neglected Tropical Diseases (NTDs) caused by a parasitic nematode known as Dracunculus medinensis and...
Dracunculiasis, also named Guinea Worm Disease (GWD), is one of the Neglected Tropical Diseases (NTDs) caused by a parasitic nematode known as Dracunculus medinensis and has been known since antiquity as 'fiery serpent' from Israelites. It is transmitted to humans via drinking contaminated water containing infective copepods. Given, its feasibility for eradication, the Guinea Worm Eradication Program (GWEP) was launched in 1980 with the aim of eradicating the disease. Since its inception, GWEP has made an extraordinary progress in interrupting transmission. Globally, the number of reported cases reduced from 3.5 million in 20 countries in 1986 to only 22 cases in 2015 from only four countries namely South Sudan, Mali, Chad and Ethiopia. Since Mali has interrupted transmission of GWD in 2016, currently, the disease remains endemic in only three sub-Saharan African countries namely, South Sudan, Chad and Ethiopia. Each endemic country has its own national Guinea Worm Eradication Program. In Ethiopia, the Ethiopian Dracunculiasis Eradication Program (EDEP) which was established in 1993 has made remarkable move towards interruption of disease transmission and now the endgame is fast approaching. The EDEP with support mainly from The Carter Center, WHO, and UNICEF has reduced GWD by more than 99% from 1994 to 2015. In 2015, only 3 indigenous cases in humans and 14 in animals (13 in dogs and 1 in baboon) were reported. In 2016, 3 human cases, 14 dogs and 2 baboon infections were reported.. Refugee influx from the Republic of South Sudan (RSS), increased animal infections with unknown role in transmission of Dracunculiasis, the presence of hard to reach communities and lack of safe water sources in remote non-village areas remain among important challenges at this final stage of GWD eradication in Ethiopia. This paper reviews progress made towards Guinea Worm Eradication with a focus on the experience of the Ethiopian Dracunculiasis Eradication Program (EDEP), and intervention strategies that need further intensification to realize the endgame. Eradication strategies encompassing community education for behavioral change including raising awareness towards cash reward for reporting Guniea Worm Disease (GWD) and animal infection, case containment, surveillance systems, provision of safe water supply, and ABATE chemical application are discussed. It also summarizes challenges the end game faces and recommendations to strengthen the eradication effort.
Topics: Animals; Communicable Disease Control; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Global Health; Humans; National Health Programs; Population Surveillance; Public Health Surveillance; Water Supply
PubMed: 28878428
DOI: No ID Found -
PLoS Neglected Tropical Diseases Apr 2017
Topics: Animals; Disease Eradication; Disease Reservoirs; Dog Diseases; Dogs; Dracunculiasis; Endemic Diseases; Ethiopia; History, 20th Century; History, 21st Century; Humans; Mali
PubMed: 28426663
DOI: 10.1371/journal.pntd.0005495 -
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 -
Emerging Infectious Diseases Apr 2016We conducted a randomized, controlled trial to test the effectiveness of a text-messaging system used for notification of disease outbreaks in Kenya. Health facilities... (Randomized Controlled Trial)
Randomized Controlled Trial
We conducted a randomized, controlled trial to test the effectiveness of a text-messaging system used for notification of disease outbreaks in Kenya. Health facilities that used the system had more timely notifications than those that did not (19.2% vs. 2.6%), indicating that technology can enhance disease surveillance in resource-limited settings.
Topics: Anthrax; Cell Phone; Disease Notification; Disease Outbreaks; Dracunculiasis; Epidemiological Monitoring; Health Facilities; Humans; Inservice Training; Kenya; Measles; Q Fever; Text Messaging; Workforce
PubMed: 26981628
DOI: 10.3201/eid2204.151459 -
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 -
Scientific Reports Jan 2020Dracunculus medinensis, the causative agent of Guinea worm disease in humans, is being reported with increasing frequency in dogs. However, the route(s) of transmission...
Dracunculus medinensis, the causative agent of Guinea worm disease in humans, is being reported with increasing frequency in dogs. However, the route(s) of transmission to dogs is still poorly understood. Classical transmission to humans occurs via drinking water that contains cyclopoid copepods infected with third stage larvae of D. medinensis, but due to the method of dog drinking (lapping) compared to humans (suction and/or retrieval of water into containers), it seems unlikely that dogs would ingest copepods readily through drinking. We exposed lab raised beagles to varying densities of uninfected copepods in 2 liters of water to evaluate the number of copepods ingested during a drinking event. We confirmed dogs can ingest copepod intermediate hosts while drinking; however, low numbers were ingested at the densities that are typically observed in Chad suggesting this transmission route may be unlikely. Overall, the relative importance of the classic transmission route and alternate transmission routes, such as paratenic and transport hosts, needs investigation in order to further clarify the epidemiology of guinea worm infections in dogs.
Topics: Animals; Chad; Communicable Disease Control; Copepoda; Disease Vectors; Dogs; Dracunculiasis; Dracunculus Nematode; Eating; Female; Humans; Male
PubMed: 31996759
DOI: 10.1038/s41598-020-58191-4 -
Emerging Infectious Diseases Aug 2016Copepods infected with Dracunculus medinensis larvae collected from infected dogs in Chad were fed to 2 species of fish and tadpoles. Although they readily ingested...
Copepods infected with Dracunculus medinensis larvae collected from infected dogs in Chad were fed to 2 species of fish and tadpoles. Although they readily ingested copepods, neither species of fish, Nile tilapia (Oreochromis niloticus) nor fathead minnow (Pimephalis promelas), were found to harbor Dracunculus larvae when examined 2-3 weeks later. Tadpoles ingested copepods much more slowly; however, upon examination at the same time interval, tadpoles of green frogs (Lithobates [Rana] clamitans) were found to harbor small numbers of Dracunculus larvae. Two ferrets (Mustela putorius furo) were fed fish or tadpoles that had been exposed to infected copepods. Only the ferret fed tadpoles harbored developing Dracunculus larvae at necropsy 70-80 days postexposure. These observations confirm that D. medinensis, like other species in the genus Dracunculus, can readily survive and remain infective in potential paratenic hosts, especially tadpoles.
Topics: Animals; Anura; Cichlids; Copepoda; Cyprinidae; Disease Reservoirs; Dracunculus Nematode; Female; Ferrets; Host-Parasite Interactions; Larva
PubMed: 27434418
DOI: 10.3201/eid2208.160043 -
Releve Epidemiologique Hebdomadaire Jan 2018
Topics: Animals; Antinematodal Agents; Chad; Disease Eradication; Disease Outbreaks; Disease Reservoirs; Dog Diseases; Dogs; Dracunculiasis; Dracunculus Nematode; Ethiopia; Humans; Mali; Sudan
PubMed: 29372633
DOI: No ID Found