Target product profile to detect prepatent "Dracunculus medinensis" infections in animals

Overview

Dracunculiasis, also known as Guinea-worm disease, is caused by infection with the parasitic nematode Dracunculus medinensis (the Guinea worm). In May 1986, the Thirty-ninth World Health Assembly declared global elimination (i.e. eradication) of dracunculiasis as a goal. The global dracunculiasis eradication campaign, through community-based interventions, has reduced the burden of the disease from an estimated 3.5 million cases per year in 1986 to only 13 human cases and 688 animal infections during 2022. To date, however, there are no validated tests to diagnose pre-patent D. medinensis infection.

A critical part of any eradication programme involves reliably identifying infected and exposed definitive hosts. Historically, the diagnosis of Guinea-worm disease was clinical in nature and occurred via visually confirming the emergence of a white worm, roughly 10–14 months after the acquisition of infection. Currently, the definitive diagnosis involves either microscopy or, if necessary, conventional polymerase chain reaction applied to a DNA preparation from emergent worm fragments. A diagnostic tool capable of confirming active infection with D. medinensis many months before the emergence of a Guinea worm would represent a leap forward for the global dracunculiasis eradication campaign.

Diagnostic modalities and platforms that can be easily used in locations where Guinea worm is observed or suspected among animal hosts are needed for the early diagnosis of prepatent Guinea worm infection to enhance follow-up and containment of infected hosts. Through the early detection and containment of Guinea worm-infected hosts, these diagnostics would ultimately serve to decrease the amount of parasite available in the environment for onward transmission. Diagnostic tools capable of detecting prepatent infection would enhance disease surveillance and provide national programme staff with additional data to identify transmission hot spots before the emergence of worms in affected areas. Diagnostic tools that can identify hosts with prepatent infection would further inform the targeting and implementation of disease-preventive interventions such as tethering of domesticated animal hosts and treating surface water sources with larvicide. Guinea worm diagnostic tools that could detect prepatent infection would also generate evidence of the absence of Guinea worm infection in definitive hosts, which could help certify countries as free of dracunculiasis transmission and ultimately facilitate the certification of dracunculiasis eradication.