Eradication Of Guinea Worm Disease Research Articles

Dog screening as a novel complementary guinea worm disease control tool to mitigate persistence in Chad: A modeling study

A free-roaming dog population remains one of the major public health problems in many developing countries. In this study, we investigated the potential impact of owned roaming and stray dogs on the persistence and possible eradication of Guinea worm disease (GWD) in Chad. We developed and analysed a multi-host of Guinea worm; and considered dogs as the definitive hosts, and fish as the intermediate hosts. Currently, GWD cases in the human population are low; hence, we ignored the human population in this study. We derived the reproduction number and explored how it depends on different model parameters that define it. We calibrated the proposed model with data from literature and validated it with recently reported GWD monthly data for dog infection in Chad from 2019 to 2022. Results show that detection and tethering of infectious owned free-roaming dogs combined with culling of stray dogs are effective disease management strategies. Hence, attainment of certain threshold levels for these interventions could lead to disease eradication. Overall, the study revealed how different factors could be applied to effectively manage GWD transmission in the dog population. Findings from this study could be used to support decision-making in GWD control strategies.Mathematics Subject Classification (2010): 92B05, 93A30, 93C15.

The Eradication of Guinea Worm Disease: A Push for Community Engagement

Guinea Worm Disease (GWD) is a neglected tropical disease caused by the nematode Dracunculus medinensis; it has been targeted for eradication since 1980. With only 14 human cases in 2021, GWD may be the first human parasitic disease to be eradicated, even without a vaccine. Current efforts to eradicate GWD face multiple challenges, the largest of which is the lack of access to safe drinking water. Other challenges include the discovery of animal hosts for D. medinensis and the seasonality of transmission. Interventions to address GWD have included water filtration systems, clean water initiatives, and health education programs, among others. Here, we argue that although enormous progress has been made, many studies fail to include a substantive discussion about community engagement. Past GWD eradication efforts have focused heavily on a vertical approach to health, which does not fully encapsulate the needs of affected communities. After reviewing literature on GWD control between 1985 and 2021, we conclude that a final push towards eradication should involve active community engagement.

Alternative transmission pathways for guinea worm in dogs: implications for outbreak risk and control

Guinea worm (Dracunculus medinensis) has exerted a high human health burden in parts of Africa. Complete eradication of Guinea worm disease (dracunculiasis) may be delayed by the circulation of the parasite in domestic dogs. As with humans, dogs acquire the parasite by directly ingesting infected copepods, and recent evidence suggests that consuming frogs that ingested infected copepods as tadpoles may be a viable transmission route (paratenic route). To understand the relative contributions of direct and paratenic transmission routes, we developed a mathematical model that describes transmission of Guinea worm between dogs, copepods and frogs. We explored how the parasite basic reproductive number (R0) depends on parameters amenable to actionable interventions under three scenarios: frogs/tadpoles do not consume copepods; tadpoles consume copepods but frogs do not contribute to transmission; and frogs are paratenic hosts. We found a non-monotonic relationship between the number of dogs and R0. Generally, frogs can contribute to disease control by removing infected copepods from the waterbody even when paratenic transmission can occur. However, paratenic transmission could play an important role in maintaining the parasite when direct transmission is reduced by interventions focused on reducing copepod ingestion by dogs. Together, these suggest that the most effective intervention strategies may be those which focus on the reduction of copepods, as this reduces outbreak potential irrespective of the importance of the paratenic route.

Ecology of domestic dogs ( Canis familiaris ) as a host for Guinea worm ( Dracunculus medinensis ) infection in Ethiopia

The global programme for the eradication of Guinea worm disease, caused by the parasitic nematode Dracunculus medinensis, has been successful in driving down human cases, but infections in non-human animals, particularly domestic dogs (Canis familiaris), now present a major obstacle to further progress. Dog infections have mainly been found in Chad and, to a lesser extent, in Mali and Ethiopia. While humans classically acquire infection by drinking water containing infected copepods, it has been hypothesized that dogs might additionally or alternatively acquire infection via a novel pathway, such as consumption of fish or frogs as possible transport or paratenic hosts. We characterized the ecology of free-ranging dogs living in three villages in Gog woreda, Gambella region, Ethiopia, in April-May 2018. We analysed their exposure to potential sources of Guinea worm infection and investigated risk factors associated with infection histories. The home ranges of 125 dogs and their activity around water sources were described using GPS tracking, and the diets of 119 dogs were described using stable isotope analysis. Unlike in Chad, where Guinea worm infection is most frequent, we found no ecological or behavioural correlates of infection history in dogs in Ethiopia. Unlike in Chad, there was no effect of variation among dogs in their consumption of aquatic vertebrates (fish or frogs) on their infection history, and we found no evidence to support hypotheses for this novel transmission pathway in Ethiopia. Dog owners had apparently increased the frequency of clean water provision to dogs in response to previous infections. Variations in dog ranging behaviour, owner behaviour and the characteristics of natural water bodies all influenced the exposure of dogs to potential sources of infection. This initial study suggests that the classical transmission pathway should be a focus of attention for Guinea worm control in non-human animals in Ethiopia.

Modeling the Effects of Spatial Heterogeneity and Seasonality on Guinea Worm Disease Transmission

Guinea worm disease is one of the neglected tropical diseases that is on the verge of elimination. Currently the disease is endemic in four countries, namely, Ethiopia, Mali, Chad, and South Sudan. Prior studies have demonstrated that climate factors and limited access to safe drinking water have a significant impact on transmission and control of Guinea worm disease. In this paper, we present a new mathematical model to understand the transmission dynamics of Guinea worm disease in South Sudan. The model incorporates seasonal variations, educational campaigns, and spatial heterogeneity. Both qualitative and quantitative analysis of the model have been carried out. Utilizing Guinea worm disease surveillance data of South Sudan (2007-2013) we estimate the model parameters. Meanwhile, we perform an optimal control study to evaluate the implications of vector control on long-term Guinea worm infection dynamics. Our results demonstrate that vector control could play a significant role on Guinea worm disease eradication.

What It Means to Be Guinea Worm Free: An Insider's Account from Ghana's Northern Region.

.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.

A mathematical study to control Guinea worm disease: a case study on Chad

ABSTRACTGlobal 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.

Turning the worm: the eradication of Guinea worm disease in west Africa

Turning the worm: the eradication of Guinea worm disease in west Africa

Global Partners Take Two Steps Closer to Eradication of Guinea Worm Disease

A 25-YEAR-OLD CAMPAIGN TO RID theworldofGuineawormdisease haswritten2moresuccessstories. The Atlanta-based Carter Center announcedrecently thateradicationefforts have halted transmission of the parasitic disease, alsoknownasdracunculiasis, in Nigeria and Niger. “WehopeGuineawormwillbethesecond disease in history to be eradicated from the face of the Earth,” said former USPresidentJimmyCarter,whofounded theCarterCenter.Smallpox, theonlyhuman disease ever eradicated, was vanquishedduringCarter’spresidency.The CarterCenterhostedaceremony inFebruarytoobservetheachievementsinboth African nations. An international campaign led by the CarterCenter launchedthebattleagainst Guineawormdiseasein1986.Atthattime, anestimated3.5millioncaseswerespread among 20 countries in Africa and Asia. Sincethen,caseshavedecreasedbymore than99%, to1800.Guineawormdisease remains endemic in 3 countries: Sudan, Mali,andEthiopia.Anannouncementthat transmissionhasbeenhalted inGhana is expected later this year. Halting transmission is not the same as being certified a disease-free country. WorldHealthOrganizationcertification requiresthatnocasesbedetectedbyexternalexpertsduring3yearsofsurveillance. Guinea worm disease is an intensely painful,potentiallycripplingparasitic infectioncontractedbydrinkingwatercontaminated with Guinea worm larvae. It takes a year for the worm to develop and emerge through a blister in the skin. “To see the sight of those people in pain, it touches you,” said Gen Yakubu Gowon, PhD, Nigeria’s former head of state, who spoke during the ceremony in Atlanta. Gowon worked with the Carter Center and other international partners, includingtheUnitedNationsDevelopment ProgrammeandUNICEF, in fieldoperations to teach Nigerian villagers how to filter theirwater toprevent infection.No effective treatmentorvaccine forGuinea worm disease exists. Eradication hinges on prevention through the use of water filters and larvicide. Ernesto Ruiz-Tiben, PhD, director of the Carter Center’s guinea worm eradicationprogram,saidhaltingtransmission in Nigeria was a tremendous challenge. “Thediseasewasalmostnationwide,”he said. In 1988, 650 000 cases were identified in nearly 6000 villages. “InNiger, thespecialchallengewasthe vastnessofthecountry,”Ruiz-Tibensaid. DespitebeingamongthepoorestofAfricannations,effectivecollaborationamong the country’s health ministry, the Carter Center,andotherpartnersenabledNiger tosuccessfullyhalttransmission,headded. The most prominent hot spot for Guinea worm disease is South Sudan, whichharbors94%ofcurrentcases.Violence between militia and rebel fighters has interrupted eradication efforts. In Chad,10caseswereconfirmed last year, a decade after transmission had been halted. Ruiz-Tiben said the exodus from the Darfur region of Sudan to refugee camps in Chad has stressed eradication programs and surveillance work.

Eradicating guinea worm without wells: unrealized hopes of the Water Decade.

At the start of the United Nations International Drinking Water Supply and Sanitation Decade in the 1980s, guinea worm disease was targeted as the major indicator of the success of the Decade's efforts to promote safe water. By the late 1980s, most of the guinea worm endemic countries in Africa and South Asia had established guinea worm eradication programmes that included water supply as one of their main technical strategies. By surveying the water supply situation in Ifeloju Local Government Area (LGA) in Oyo State, Nigeria, in June 1996, as a case study, it was possible to determine the role that water supply has played in the eradication effort. Although two major agencies, the former Directorate for Food, Roads and Rural Infrastructure and UNICEF, provided hand dug and bore-hole wells respectively in many parts of the LGA, coverage of the smaller farm hamlets has been minor compared to efforts in the larger towns. This is ironic because the farm hamlets served as a reservoir for the disease in the 1980s, such that when the piped water system in the towns broke down, guinea worm was easily reintroduced into the towns. The survey of 188 ever-endemic hamlets with an estimated population of 23,556 found that 74.3% of the people still drink only pond water. Another 11.3% have wells that have become dysfunctional. Only 14.4% of this rural population has access' to functioning wells. Guinea worm was eliminated from 107 of the hamlets mainly by the use of cloth filters and chemical treatment of ponds. While this proves that it is possible to eradicate guinea worm, it fails to leave behind the legacy of reliable, safe water supplies that was the hope of the Water Decade.

Community participation in the eradication of guinea worm disease

As Guinea worm eradication programmess have got under way in endemic countries over the last decade, there has been shift toward more participatory methods. The approach to surveillance has changed from periodic cross-sectional surveys to monthly village-based reporting of cases by a volunteer village health worker. At the same time, the emphasis regarding control interventions has moved from the provision of safe water supplied to health educatioon. The new approach has proved very effective. The village health volunteers who carry out both surveillance and health seem to be motivated largerly by the the social status of their role; still more commitment will the required of them in the final stages of eradication. It is be hoped that the networks of village health workers established for Guinea worm eradication will find a useful role in health promotion after the worms have gone.

Guinea worm disease in Ayod, Upper Nile Province, southern Sudan: a cross-sectional study.

Upper Nile Province is one of the four main endemic areas for Guinea worm disease in the Sudan. In December 1994, a survey was conducted in the village of Ayod where the disease is endemic, to investigate morbidity and local knowledge of transmission and prevention. Interviews were conducted in households selected by standard cluster sampling procedures and of the 759 people examined, 156 (20.6%) had Guinea worm lesions. Adjusted odds ratios were used to estimate the relative risk for people with different personal or household characteristics in a multivariate analysis. After controlling for the possible confounding effects of other study variables, having a filter in the household, gender, and lack of knowledge about transmission and about prevention, were not associated with lesions. Only two variables were significantly associated with Guinea worm disease: getting water from a source other than a well increased the risk by a factor of 2.3, and being aged 5 years or more increased the risk by a factor of 31.1. This study demonstrates the clear association between the source of water for drinking and Guinea worm disease found elsewhere. We suggest the provision of reliable sources of pure drinking water and health education are the most suitable long-term preventive measures. The Sudan now represents the greatest challenge to the goal of global eradication of Guinea worm disease, following the reduction in cases in Nigeria. The continuing civil war and insecurity in southern Sudan hinder the implementation of an effective water programme and other control measures, but the potential benefits through reduced incapacity and improved agricultural productivity are considerable.

Switzerland (WHO): Eradication of guineaworm disease

Switzerland (WHO): Eradication of guineaworm disease