The National Guinea Worm Eradication Programme in Chad plans to deploy all existing eradication strategies to achieve interruption of transmission of dracunculiasis in both humans and animals. The reassessment reflects the country’s determination to overcome the challenges it currently faces.
Our strategy may have some weaknesses, and that is the whole point; because when you understand the mechanism you just have to break the chain to stop [transmission], but there are issues that are eluding us, which are allowing transmission to continue.
Dr Ndoundo was speaking during the annual informal meeting of health ministers of guinea-worm endemic countries during the Seventy-first World Health Assembly in Geneva on 23 May 2018.
Chad is the only country that has reported 3 human cases so far this year, along with 409 infections in dogs. Transmission in humans has been reported since 2010 after almost a decade of reporting zero cases. Infection among dogs was confirmed in 2012 in Chad; the number of infections fell from 1011 (in 2016) to 817 (in 2017).
“I can think of no other disease where there has been such a fundamental shift … as we are facing with guinea-worm,” said Dr Dean Sienko, Vice President for health programmes at The Carter Center. “I can think of no other disease where in the recent past it was only a human disease and thought to be transmitted through drinking contaminated water. Now we have a huge shift and … the final hurdle is with the animals.”
The mode of transmission to dogs is still being investigated after it was found that the worms infecting dogs are genetically undistinguishable from those emerging in humans. Infected dogs continue to be detected in the area along the Chari River and its tributaries.
To contain this unusual epidemiology, WHO and The Carter Center are considering various possible scenarios, but the main one focuses on applying cyclopicide to all eligible surface water bodies in and around the estimated 306 villages that reported guinea-worm infection in 2017. The aim is to reduce the likelihood of transmission from cyclops that harbour the infective guinea-worm larvae.
Another problem facing global eradication is insecurity of, and limited access to, regions considered to be endemic for the disease, including at-risk border areas.
“Insecurity remains a problem in all of the [currently] endemic countries [as] they prevent our ability to understand what is happening with the few remaining infected animals or human cases, and they also impede our ability to apply interventions,” said Dr Sienko.
Many countries which have already been declared free of dracunculiasis transmission are committed to continued vigilance through their respective Integrated Disease Surveillance and Response programmes and have affirmed their readiness to implement a global cash reward scheme which WHO plans to develop and launch in a few years.
To overcome last mile challenges, WHO Director-General Dr Tedros Adhanom Ghebreyesus called on countries to intensify vector control measures, to set up a mechanism in countries reporting cases to review progress every month and to show enhanced political commitment by having a Minister visit endemic areas at least once a year.
"I look forward to the day I can unveil a statue commemorating the eradication of guinea-worm disease" said Dr Tedros.