SEATTLE — Dracunculiasis, commonly known as Guinea worm disease, is a neglected tropical disease and parasitic infection stemming from drinking water contaminated with Guinea worm larvae. The larvae mate and grow inside a human’s abdomen, growing up to one meter long and leading to skin lesions. The presence of a worm in the body is incredibly painful and can incapacitate infected persons for long periods of time. Removal of the worm is done manually by pulling the worm out of the lesion. A full removal can take weeks. Since 1986, Guinea worm eradication has become a top priority for the Carter Center and other partner organizations.
Guinea worm is found in the poorest 10 percent of the world’s population due to lack of access to clean drinking water. There are no drugs or vaccines for this disease, but Guinea worm eradication is possible through public health education, access to safe drinking water and filtering of drinking water. When the Guinea worm eradication campaign first began in 1986, 3.5 million people in Africa and Asia were infected with Guinea worm; as of 2016, there has been a 99.9 percent reduction, with only 25 reported cases.
However, in Chad, one of the four remaining endemic countries, infections began arising in an irregular pattern after almost a decade of no Guinea worm cases. Rather than being clustered in villages, cases were sporadic. In 2015, researchers found nearly 500 infections in dogs. They believe that dogs are transmitting Guinea worm to humans. Prior to this discovery, there were only rare cases occurring in leopards and dogs. These infections were not thought to be transmissible to humans.
Cases in dogs continue to rise, with more than 1,000 reported in 2016. Several steps have been put in place to try and prevent Guinea worm cases in dogs and transmissions to humans. An active surveillance system in more than 1,000 villages was established. This may be responsible for the sharp rise in the known number of cases. A key component of this program is monetary rewards for reporting of dogs with Guinea worm. Education programs are also being modified to include awareness of the presence of Guinea worm in dogs. More than 2,000 volunteers have been trained throughout monitored villages on how to identify Guinea worm in dogs and prevent transmission.
Villagers are encouraged to tie up any infected dogs for up to two weeks while the worm works its way out of the animal. Collars and chains have been distributed throughout the villages for this purpose.
Research is also underway to determine how dogs are becoming infected. Because the bulk of cases are found in villages along the Chari River, one hypothesis suggests the dogs are eating the discarded remains of fish that are infested with larvae. Rather than euthanizing dogs for examination, the Carter Center has utilized GPS trackers to determine where the dogs are going prior to infections. The center also uses radioisotopes to analyze food particles found on their whiskers.
Former president Jimmy Carter, the head of the Carter Center’s campaign, has declared that his mission is for the last Guinea worm to die before he does. The World Health Organization cannot certify Chad Guinea worm-free until the Guinea worm is eliminated in both humans and dogs. This presents a new obstacle in a successful eradication campaign. However, scientists and public health officials are confident that modifying education programs and finding the root cause of Guinea worm presence in animals will only be a minor hiccup in the Guinea worm eradication campaign.
– Nicole Toomey