Female Guinea worm,
Dracunculus medinensis, emerging from the foot of a victim.
Creationist mode: 
Until recently, it looked like scientists could be on the verge of eradicating another of the divine malevolence's nasty little parasites, like they did with smallpox and the disease in African cattle - Rinderpest.
This time, the disease was the disgusting parasitic worm, the Guinea worm,
Dracunculus medinensis, which I described in my popular, illustrated book,
The Malevolent Designer: Why Nature's God is not Good, p 87..
A person becomes infected with the Guinea worm when they drink water containing water fleas that are carrying the larval form of the worm. The water fleas are killed in the stomach, releasing the larvae which penetrate the stomach wall and enter the peritoneum. Here, male and female worms mature, pair up and mate. The male then dies but the female migrates to the subcutaneous tissues and grows to about 2 mm wide and up to a metre long. After 10-14 months she moves around in the subcutaneous tissues, often causing intense pain and eventually migrating to the lower leg or foot where she forms a painful, burning blister which can be relieved by immersion in water. When the foot is in water, the female emerges from the blister and begins to shed larvae which infect water fleas to begin the cycle again. The resulting wound may ulcerate and may become infected with opportunist bacteria such as tetanus. Secondary infections have necessitated limb amputations.
Guine worm being extracted
So successful has the eradication campaign been that infections had fallen from about 3.5 million in 1986, in some of the poorest parts of the world, such as Chad, Ethiopia, Mali and South Sudan, to just 27 in 2020, all in Chad, and
D. mediensis looked to be on the verge of extinction. A major part of this campaign was the simple expedient of filtering the water through cloth, which was enough to remove water fleas.
But, as any devotee of Creationism's putative creator god will tell you, the malevolence who creates these nasty little parasites with which to make its creation suffer, is often well ahead of the game in its battles with medical science, so, true to form, it has stepped in in the nick of time with a brilliant master-stroke which means it is much more difficult now to eradicate it.
Scientists working at the University of Exeter, UK, have discovered that the worm now infect domestic dogs, cats and maybe wild animals such as wild cats too. But it is not as simple as that. To get the worms into dogs and cats, it have adapted it so it lives in the digestive tract of fish inside the water fleas that they eat, which are then eaten by dogs and cats when human catch the fish and either throw them away or gut them before cooking them. Inside the mammalian digestive tract, the worm larvae are liberated from the water fleas, just like they are when ingested in drinking water by humans.
Guinea worm is now most widespread in Chad, where
according to the CDC, 1,582 of the 1,625 (97.4%) worm infections detected worldwide were recorded in 2020. Of these, 1,507 (92.7%) were in domestic dogs, 61 in domestic cats, and 2 in wild felids, compared to only 12 in humans.
So feral and domestic animals are now acting as a reservoir of these worms, making it much more difficult to eradicate them because you just can't get cats and dogs to filter their drinking water.
Brilliant, eh? There's no stopping the divine malevolence once it decides to make life miserable for people, as it did with Africans and the Guinea worm. Africans seem to be its favourite victims judging by the number of these nasty parasites to be found there, especially in the tropical parts, what with these and other worms, mosquito-borne diseases like malaria, zika and yellow fever and sleeping sickness carried by tsetse flies, on top of the regular famines and malnutrition caused by drought and crop failures.
Creationist mode: 
Now the science, rather than the childish superstition.
Dogs are now the key impediment to eradicating this dreadful human disease.
Our work shows that fisheries, and the facilitation of dogs eating fish, are likely contributing to the persistence of Guinea worm in Chad.
The challenge now is that this pathogen must be eliminated not only from people but also from animals.
This is a clear example of where a 'One Health' approach to integrating health of people, animals and the environment is required to eradicate this debilitating human disease.
Professor Robbie McDonald, Lead author
Environment and Sustainability Institute
University of Exeter, Penryn, Devon, UK
Here is how the Exeter University scientists made their discovery, as explained in the news release:
Targeted surveillance showed that in 2020, 93% of Guinea worms detected worldwide were in dogs in Chad, in central Africa.
Research by the University of Exeter, published today in Current Biology, has revealed a new pathway for transmission – by dogs eating fish that carry the parasite larvae. This means dogs maintain the parasite’s life-cycle and humans can still catch the disease.
The researchers worked for a year in several of the worst-affected villages along the River Chari in Chad.
They tracked hundreds of dogs with satellite tags to analyse movements, and revealed dog diets throughout the year using forensic stable isotope analysis of dog whiskers.
Much of the fish eaten by the dogs – usually guts or smaller fish – was discarded by humans fishing on the river and its lagoons.
In the abstract to their paper in
Current Biology, the authors say:
Highlights
- Reservoirs of infection in dogs impede eradication of human Guinea worm disease.
- We analyzed disease risk in dogs in Chad where Guinea worm is most common.
- Disease is associated with consumption of fish made available by seasonal fisheries.
- Novel transmission pathway highlights value of One Health for disease eradication.
Summary
Exploitation of natural resources is a driver of human infectious disease emergence. The emergence of animal reservoirs of Guinea worm Dracunculus medinensis, particularly in domestic dogs Canis familiaris, has become the major impediment to global eradication of this human disease. 93% of all Guinea worms detected worldwide in 2020 were in dogs in Chad. Novel, non-classical pathways for transmission of Guinea worm in dogs, involving consumption of fish, have been hypothesized to support the maintenance of this animal reservoir. We quantified and analyzed variation in Guinea worm emergence in dogs in Chad, across three climatic seasons, in multiple villages and districts. We applied forensic stable isotope analyses to quantify dietary variation within and among dogs and GPS tracking to characterize their spatial ecology. At the end of the hot-dry season and beginning of the wet season, when fishing by people is most intensive, Guinea worm emergence rates in dogs were highest, dogs ate most fish, and fish consumption was most closely associated with disease. Consumption of fish by dogs enables a non-classical transmission pathway for Guinea worm in Chad. Seasonal fisheries and the facilitation of dogs eating fish are likely contributing to disease persistence and to this key impediment to human disease eradication. Interrelated natural resource use, climatic variation, companion animal ecology, and human health highlight the indispensability of One Health approaches to the challenges of eradicating Guinea worm and other zoonotic diseases.
The thing is, there are so many of these examples of how, if there really were an intelligent designer with the characteristics Creationists like to attribute to their favourite god - omniscience and omnipotence - it could only be described as a malevolent sadist as well as an incompetent designer. I certainly found enough to fill a book with and could probably write another if it wasn't simpley making the same point again. What other reason could there be for changing the MO of the Guinea worm so it can avoid being eradicated by medical science?
This is, of course, why you can never get an ID advocate to discuss parasites and parasitism, other than to blame their mythical first pair, Adam and Eve as though 'sin' itself is a sentient, creative entity capable of designing things like the Guinea worm, the SARS-CoV-2 virus and childhood cancers. Certainly, none of it make any sense as the work of an intelligent, omniscient, omni-benevolent designer.
It is, of course, entirely explained as the result of an unplanned, mindless and so amoral, process involving nothing more than chemistry and physics and the inevitable result of natural selection acting on random variations in a population. For some inexplicable reason though, Creationists would rather present their god as an evil monster rather than accept the demonstrable and observable fact of evolution.
