Progress Toward Global Eradication of Dracunculiasis — January 2018–June 2019

Hopkins, Donald R.; Weiss, Adam; Roy, Sharon L.; Zingeser, J.; Guagliardo, Sarah Anne J.

doi:10.15585/mmwr.mm6843a5

Cited by 17 publications

(32 citation statements)

References 8 publications

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“… 20 In the Guinea worm context, dog mobility has been observed in Chad, 17 and although the parasites themselves are not mobile, they are carried by other mobile hosts including humans and cats. 2 , 3 …”

Section: Discussionmentioning

confidence: 99%

“… 1 The program has been enormously successful, reducing the number of human cases to just 54 in four countries in 2019. 2 , 3 Yet eradication efforts are challenged by ongoing transmission of the parasite in domestic dogs in Chad, 4 , 5 where most human and canine cases also occur today. 2 , 3 Although canine cases of Guinea worm have been historically well documented, 4 , 6 – 13 questions remain about transmission dynamics in dogs.…”

Section: Introductionmentioning

confidence: 99%

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Correlates of Variation in Guinea Worm Burden among Infected Domestic Dogs

Guagliardo

Wiegand

Roy

et al. 2021

The American Journal of Tropical Medicine and Hygiene

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The Guinea Worm Eradication Program has been extraordinarily successful—in 2019, there were 53 human cases reported, down from the estimated 3.5 million in 1986. Yet the occurrence of guinea worm in dogs is a challenge to eradication efforts, and underlying questions about transmission dynamics remain. We used routine surveillance data to run negative binomial regressions predicting worm burden among infected dogs in Chad. Of 3,371 infected dogs reported during 2015–2018, 38.5% had multiple worms. A multivariable model showed that the number of dogs in the household was negatively associated with worm burden (adjusted incidence rate ratio [AIRR] = 0.95, 95% CI: 0.93–0.97, P < 0.0001) after adjusting for dog age (AIRR = 0.99, 95% CI: 0.96–1.01, P > 0.1). This could relate to the amount of infective inocula (e.g., contaminated food or water) shared by multiple dogs in a household. Other significant univariable associations with worm burden included dog history of guinea worm infection (IRR = 1.30, 95% CI: 1.18–1.45) and dog owners who were hunters (IRR = 0.78, 95% CI: 0.62–0.99, P < 0.05) or farmers (IRR = 0.83, 95% CI: 0.77–0.90, P < 0.0001). Further analysis showed that the number of dogs in the household was significantly and positively correlated with nearly all other independent variables (e.g., owner occupation: farmer, fisherman, or hunter; dog age, gender, and history of guinea worm). The associations we identified between worm burden and dogs per household, and dogs per household and owner characteristics should be further investigated with more targeted studies.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Correlates of Variation in Guinea Worm Burden among Infected Domestic Dogs

Guagliardo

Wiegand

Roy

et al. 2021

The American Journal of Tropical Medicine and Hygiene

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“…Within the Chad Guinea Worm Eradication Program (CGWEP), surveillance and eradication are closely linked because the objective of the surveillance system is to detect and “contain” every case of Guinea worm in Chad, meaning that human and canine cases are kept away from water sources to prevent contamination and future spread. Containment is operationalized by tethering infected dogs until all worms are removed and wounds are fully healed, and by identifying human cases within 24 hours of worm emergence and providing medical care at a Guinea worm containment center, medical clinic, or hospital until all worms are removed [ 21 ]. Timing is critical for containment; worm emergence may occur within a few hours of development of a visible blister, and the human case or infected animal can quickly contaminate water sources.…”

Section: Introductionmentioning

confidence: 99%

Community-based Guinea worm surveillance in Chad: Evaluating a system at the intersection of human and animal disease

et al. 2021

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Background Guinea worm is a debilitating parasitic infection targeted for eradication. Annual human cases have dropped from approximately 3,500,000 in 1986 to 54 in 2019. Recent identification of canine cases in Chad threatens progress, and therefore detection, prevention, and containment of canine cases is a priority. We investigated associations between disease knowledge, community engagement, and canine cases in Chad to identify opportunities to improve active surveillance. Methods We surveyed 627 respondents (villagers, local leaders, community volunteers, and supervisors) across 45 villages under active surveillance. Descriptive statistics were analyzed by respondent category. Logistic regression models were fitted to assess the effects of volunteer visit frequency on villager knowledge. Results Knowledge increased with respondents’ associations with the Guinea worm program. Household visit frequency by community volunteers was uneven: 53.0% of villagers reported visits at least twice weekly and 21.4% of villagers reported never being visited. Villagers visited by a volunteer at least twice weekly had better knowledge of Guinea worm symptoms (OR: 1.71; 95% CI: 1.04–2.79) and could name more prevention strategies (OR: 2.04; 95% CI: 1.32–3.15) than villagers visited less frequently. The primary motivation to report was to facilitate care-seeking for people with Guinea worm. Knowledge of animal “containment” to prevent contamination of water, knowledge of rewards for reporting animal cases, and ability to name any reasons to report Guinea worm were each positively correlated with village canine case counts. Conclusions Community volunteers play crucial roles in educating their neighbors about Guinea worm and facilitating surveillance. Additional training and more attentive management of volunteers and supervisors could increase visit frequency and further amplify their impact. Emphasizing links between animal and human cases, the importance of animal containment, and animal rewards might improve surveillance and canine case detection. The surveillance system should be evaluated routinely to expand generalizability of data and monitor changes over time.

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“…The eradication campaign for dracunculiasis, Guinea worm disease, has made substantial progress since the first set of World Health Assembly resolutions aimed at elimination efforts passed during the International Drinking Water Supply and Sanitation Decade (1981-1990) [8]. The Guinea worm eradication campaign has decreased the global burden of disease by more than 99% [28], enabled the World Health Organization (WHO) to certify 187 countries as free from endemic Dracunculiasis transmission [3], and decreased the significant economic loss in rural settings [8]. Despite the substantial progress, endemic transmission has persisted in Angola, Chad, Ethiopia, Mali, and South Sudan [28].…”

Section: Introductionmentioning

confidence: 99%

“…The Guinea worm eradication campaign has decreased the global burden of disease by more than 99% [28], enabled the World Health Organization (WHO) to certify 187 countries as free from endemic Dracunculiasis transmission [3], and decreased the significant economic loss in rural settings [8]. Despite the substantial progress, endemic transmission has persisted in Angola, Chad, Ethiopia, Mali, and South Sudan [28]. In Chad, a decade long absence of reported cases was interrupted with a detected resurgence of Guinea worm cases in 2010 [45]; moreover, human cases continue to be reported [2] with a growing understanding of the role of animal reservoirs in transmission [10, 19, 38, 12, 47].…”

Section: Introductionmentioning

confidence: 99%

Linked surveillance and genetic data uncovers programmatically relevant geographic scale of Guinea worm transmission in Chad

Ribado

Thiele

et al. 2020

Preprint

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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 data from 2012-2018 cases to investigate the modes of transmission between hosts and the geographic connectivity for genetically similar worm populations. Eighty-six variants across three loci on the mitochondrial genome identified 41 genetically distinct worm genotypes. Spatiotemporal modeling reveals genetically identical worms are within a median range of 18.6 kilometers of each other, but largely within approximately 50 kilometers. Genetically identical worms vary in their degree of spatial clustering, suggesting there may be different factors that favor or constrain transmission. Each worm is surrounded by five to ten genetically distinct worms within a 50 kilometer radius. In an independent population, we show that more variants revealed in whole mitochondrial genome data improved the discrimination between worm pairs. Conclusions/Significance In the largest study linking genetic and surveillance data to date of Guinea worm cases in Chad, we show genetic similarity and modeling can contribute to understanding local transmission. The overlap of genetically distinct worms in quantitatively identified transmission ranges highlights the necessity for genomic tools to link cases. The improved discrimination between worm pairs from variants identified across the complete mitochondrial genome indicates expanding 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.

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Progress Toward Global Eradication of Dracunculiasis — January 2018–June 2019

Cited by 17 publications

References 8 publications

Correlates of Variation in Guinea Worm Burden among Infected Domestic Dogs

Correlates of Variation in Guinea Worm Burden among Infected Domestic Dogs

Community-based Guinea worm surveillance in Chad: Evaluating a system at the intersection of human and animal disease

Linked surveillance and genetic data uncovers programmatically relevant geographic scale of Guinea worm transmission in Chad

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