Dogs and the classic route of Guinea Worm transmission: an evaluation of copepod ingestion

Kayla B Garrett,Erin K Box,Michael J Yabsley,Christopher A Cleveland,Ania A Majewska

doi:10.1038/s41598-020-58191-4

Kayla B Garrett, Erin K Box + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-58191-4

Copy DOI

Journal: Scientific Reports	Publication Date: Jan 29, 2020
Citations: 17	License type: open-access

Affiliation: University of Georgia, Emory University

Abstract

Dracunculus medinensis, the causative agent of Guinea worm disease in humans, is being reported with increasing frequency in dogs. However, the route(s) of transmission to dogs is still poorly understood. Classical transmission to humans occurs via drinking water that contains cyclopoid copepods infected with third stage larvae of D. medinensis, but due to the method of dog drinking (lapping) compared to humans (suction and/or retrieval of water into containers), it seems unlikely that dogs would ingest copepods readily through drinking. We exposed lab raised beagles to varying densities of uninfected copepods in 2 liters of water to evaluate the number of copepods ingested during a drinking event. We confirmed dogs can ingest copepod intermediate hosts while drinking; however, low numbers were ingested at the densities that are typically observed in Chad suggesting this transmission route may be unlikely. Overall, the relative importance of the classic transmission route and alternate transmission routes, such as paratenic and transport hosts, needs investigation in order to further clarify the epidemiology of guinea worm infections in dogs.

Highlights

Guinea worm disease (GWD), caused by Dracunculus medinensis, is a painful and debilitating disease that is historically widespread in humans among sub-Saharan Africa and southern Asia
Copepod consumption varied somewhat among individuals (Fig. 1a), and statistical analysis showed that the number of copepods consumed was positively influenced by the initial number of copepods presented to a dog (z = 6.6, p < 0.001)
We found that higher densities of copepods led to higher ingestion rates

Summary

Introduction

Guinea worm disease (GWD), caused by Dracunculus medinensis, is a painful and debilitating disease that is historically widespread in humans among sub-Saharan Africa and southern Asia. Transmission of D. medinensis is considered to occur through the ingestion of infected copepods in contaminated drinking water. In a first step to investigating the relative importance of these different transmission routes, we conducted this study to determine if dogs ingest copepods during a drinking event and, if so, to quantify ingestion at different copepod densities.

Results

Conclusion