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International Journal For Parasitology.... Dec 2018Nematodes are an extremely diverse and speciose group of parasites. Adult dracunculoid nematodes (Superfamily Dracunculoidea) occur in the tissues and serous cavities of... (Review)
Review
Nematodes are an extremely diverse and speciose group of parasites. Adult dracunculoid nematodes (Superfamily Dracunculoidea) occur in the tissues and serous cavities of mammals, fish, reptiles, amphibians and birds. Of the dracunculid group, perhaps best known is , the human Guinea Worm. Considerable work has been done on ; however recent infections in peri-domestic dogs and the finding of naturally-infected paratenic hosts (previously unreported for ) indicate we still have much to learn about these parasites. Furthermore, among eight species in the Old World and six species in the New World there is a lack of general life history knowledge as well as questions on species occurrence, host diversity, and transmission dynamics. Herein, we provide a comprehensive review of the genus , in order of a theoretical evolutionary progression from reptilian to mammalian hosts. Species descriptions, where available, are provided but also show where gaps occur in our knowledge of various species. Additionally, many first reports of spp. were done prior to the development and use of molecular tools. This is especially important for this group of parasites as speciation based on morphology is only applicable to males of the genus, and males, given their size, are notoriously difficult to recover from definitive hosts. Therefore, we also discuss current molecular tools used in the investigation of this group of parasites. Given recent host-switching events, the dracunculids are of increasing importance and require further work to expand our understanding of this genus.
PubMed: 30094178
DOI: 10.1016/j.ijppaw.2018.07.002 -
Annals of Parasitology 2018The pattern of infection with the nematode Parapharyngodon riojensis in the lizard Phymaturus extrilidus in a Puna area, central-west Argentina was studied. No...
Pattern of infection with Parapharyngodon riojensis Ramallo, Bursey, Goldberg 2002 (Nematoda: Pharyngodonidae) in the lizard Phymaturus extrilidus from Puna region, Argentina.
The pattern of infection with the nematode Parapharyngodon riojensis in the lizard Phymaturus extrilidus in a Puna area, central-west Argentina was studied. No significant prevalence differences were found between sexes or seasons sampled. However, there were differences in mean intensity between the summer (dry period) and autumn (wet period) seasons. Mean intensity was higher in the moistest season, associated with low body condition in P. extrilidus. The genus Parapharyngodon has a direct life cycle, and environmental moisture could favor higher intensity in the rainy period. The present study provides the first data on the parasitic ecology of P. extrilidus from Argentina.
Topics: Animals; Argentina; Dracunculus Nematode; Female; Lizards; Male; Nematode Infections; Seasons
PubMed: 29983018
DOI: 10.17420/ap6402.137 -
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 -
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 -
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 -
Applied and Environmental Microbiology May 2018The adjustment of metabolic patterns is fundamental to fungal biology and plays vital roles in adaptation to diverse ecological challenges. Nematode-trapping fungi can...
The adjustment of metabolic patterns is fundamental to fungal biology and plays vital roles in adaptation to diverse ecological challenges. Nematode-trapping fungi can switch their lifestyle from saprophytic to pathogenic by developing specific trapping devices induced by nematodes to infect their prey as a response to nutrient depletion in nature. However, the chemical identity of the specific fungal metabolites used during the switch remains poorly understood. We hypothesized that these important signal molecules might be volatile in nature. Gas chromatography-mass spectrometry was used to carry out comparative analysis of fungal metabolomics during the saprophytic and pathogenic lifestyles of the model species Two media commonly used in research on this species, cornmeal agar (CMA) and potato dextrose agar (PDA), were chosen for use in this study. The fungus produced a small group of volatile furanone and pyrone metabolites that were associated with the switch from the saprophytic to the pathogenic stage. fungi grown on CMA tended to produce more traps and employ attractive furanones to improve the utilization of traps, while fungi grown on PDA developed fewer traps and used nematode-toxic furanone metabolites to compensate for insufficient traps. Another volatile pyrone metabolite, maltol, was identified as a morphological regulator for enhancing trap formation. Deletion of the gene in led to increased amounts of the furanone attractant (2-fold) in mutants and enhanced the attractive activity (1.5-fold) of the fungus, while it resulted in decreased trap formation. This investigation provides new insights regarding the comprehensive tactics of fungal adaptation to environmental stress, integrating both morphological and metabolomic mechanisms. Nematode-trapping fungi are a unique group of soil-living fungi that can switch from the saprophytic to the pathogenic lifestyle once they come into contact with nematodes as a response to nutrient depletion. In this study, we investigated the metabolic response during the switch and the key types of metabolites involved in the interaction between fungi and nematodes. Our findings indicate that develops multiple and flexible metabolic tactics corresponding to different morphological responses to nematodes. can use similar volatile furanone and pyrone metabolites with different ecological functions to help capture nematodes in the fungal switch from the saprophytic to the pathogenic lifestyle. Furthermore, studies with mutants with increased furanone and pyrone metabolites confirmed the results. This investigation reveals the importance of volatile signaling in the comprehensive tactics used by nematode-trapping fungi, integrating both morphological and metabolomic mechanisms.
Topics: Animals; Ascomycota; Dracunculus Nematode; Food Chain; Gas Chromatography-Mass Spectrometry; Metabolome; Metabolomics; Morphogenesis; Signal Transduction; Volatile Organic Compounds
PubMed: 29453265
DOI: 10.1128/AEM.02749-17 -
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 -
MMWR. Morbidity and Mortality Weekly... Dec 2017Dracunculiasis (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 emerges through the skin, usually on a lower limb (1). Pain and secondary bacterial infection can cause temporary or permanent disability that disrupts work and schooling. The campaign to eradicate dracunculiasis worldwide began in 1980 at CDC. In 1986, the World Health Assembly called for dracunculiasis elimination,* and the global Guinea Worm Eradication Program, led by the Carter Center and supported by the World Health Organization (WHO), United Nations Children's Fund, CDC, and other partners, began assisting ministries of health in countries with endemic dracunculiasis. In 1986, an estimated 3.5 million cases occurred each year in 20 countries in Africa and Asia (2). Since then, although the goal of eradicating dracunculiasis has not been achieved, considerable progress has been made. Compared with the 1986 estimate, the annual number of reported cases in 2016 has declined by >99%, and cases are confined to three countries with endemic disease. This report updates published (3-4) and unpublished surveillance data reported by ministries of health and describes progress toward dracunculiasis eradication during January 2016-June 2017. In 2016, a total of 25 cases were reported from three countries (Chad [16], South Sudan [six], Ethiopia [three]), compared with 22 cases reported from the same three countries and Mali in 2015 (Table 1). The 14% increase in cases from 2015 to 2016 was offset by the 25% reduction in number of countries with indigenous cases. During the first 6 months of 2017, the overall number of cases declined to eight, all in Chad, from 10 cases in three countries (Chad [four], South Sudan [four] and Ethiopia [two]) during the same period of 2016. Continued active surveillance, aggressive detection, and appropriate management of cases are essential eradication program components; however, epidemiologic challenges, civil unrest, and insecurity pose potential barriers to eradication.
Topics: Disease Eradication; Dracunculiasis; Global Health; Humans
PubMed: 29216028
DOI: 10.15585/mmwr.mm6648a3 -
PLoS Neglected Tropical Diseases Oct 2017Of the three diseases targeted for eradication by WHO, two are so-called Neglected Tropical Diseases (NTDs)-guinea worm disease (GWD) and yaws. The Guinea Worm...
BACKGROUND
Of the three diseases targeted for eradication by WHO, two are so-called Neglected Tropical Diseases (NTDs)-guinea worm disease (GWD) and yaws. The Guinea Worm Eradication Programme (GWEP) is in its final stages, with only 25 reported in 2016. However, global eradication still requires certification by WHO of the absence of transmission in all countries. We analyze the cost-effectiveness of the GWEP in the end game, when the number of cases is lower and the cost per case is higher than at any other time. Ours is the first economic evaluation of the GWEP since a World Bank study in 1997.
METHODS
Using data from the GWEP, we estimate the cost of the implementation, pre-certification and certification stages. We model cost-effectiveness in the period 1986-2030. We compare the GWEP to two alternative scenarios: doing nothing (no intervention since 1986) and control (only surveillance and outbreak response during 2016-2030). We report the cost per case averted, cost per disability adjusted life year (DALY) averted and cost per at-risk life year averted. We assess cost-effectiveness against a threshold of about one half GDP per capita (less than US$ 500 in low income countries). All costs are expressed in US$ of 2015.
RESULTS
The GWEP cost an estimated US$ 11 (95% uncertainty interval, 4.70-12.49) per case averted in the period 1986-2030. The pre-certification and certification phases can cost as much as US$ 0.0041 and US$ 0.0015 per capita per year. The cost per DALY averted by the GWEP relative to doing nothing is estimated at US$ 222 (118-372) in 1986-2030. The GWEP is probably more cost-effective than control by the year 2030. The GWEP is certainly more cost-effective than control if willingness to pay for one year of life lived without the risk of GWD exceeds US$ 0.10.
DISCUSSION
Even if economic costs are two times as high as the financial costs estimated for the period to 2020, the GWEP will still be cost-effective relative to doing nothing. Whether the GWEP turns out to be the most cost-effective alternative in the period beyond 2015 depends on the time horizon. When framed in terms of the number of years of life lived without the risk of GWD, a case can be made more easily for finishing the end game, including certification of the absence of transmission.
Topics: Animals; Cost-Benefit Analysis; Disease Eradication; Dracunculiasis; Dracunculus Nematode; Humans; Neglected Diseases
PubMed: 28981510
DOI: 10.1371/journal.pntd.0005922 -
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