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Could Tongue-eating isopods appear in humans?

The tongue-eating isopod, technically known as the Cymothua Exigua, is a parasite that works in the following...

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Could Tongue-eating isopods appear in humans?

The tongue-eating isopod, technically known as the Cymothua Exigua, is a parasite that works in the following way:

It starts as sea lice and enters the fish through the gills. From there it burrows into its fish host and takes up position on the fish's tongue, where it lives on the host's blood. As the tongue is starved of blood it atrophies and is gradually replaced by the isopod! Previously it was thought that the fish is able to survive the experience with no apparent harm other than the loss of its tongue to the isopod, however, recent evidence is suggesting otherwise. The isopod can indeed be harmful.

In 2003, for example, scientists studying isopods in a fish farm off the coast of Turkey found that sea bass with the parasites in their mouths had lower blood counts than ones that still had their tongues intact. The isopods feed away on their blood, like leaches.

In other studies, a key component to isopods doing more damage to fish is directly related to overfishing. In the Mediterranean, scientists not only discovered that there were more parasites in heavily fished waters, but that fish with tongue parasites ended up smaller and lighter in the heavily fished waters than infested fish in a fishing refuge that controls for overfishing. Heavy fishing is driving an evolution towards smaller fish (fish that get to be sexually mature faster and thus cease growing earlier in their life cycle may be more likely to have offspring than fish that take their time to reach bigger sizes). In this evolution paradigm, smaller fish end up unable to defend themselves against enemies, such as tongue-eating isopods. In the case of Sea Bream, 47 percent were found to be infected with the tongue-eating isopod!

Don?t worry, if you happened to have had Sea Bream for dinner in the recent past, you?re fine. The parasite does not seem to cause human disease, particularly if you cook your fish. Taking away the fact that almost half of a fish species is infected with isopods and letting that image sit in your head when you have your next meal of sushi, the question that fascinates me most is could the tongue-eating isopod one day effect humans?

There is a long history of disease transferring from insects, animals, and mammals to human. The Ebola Virus, HIV, Malaria are the most well known of these. The general rule of thumb for when animal disease goes from only infecting animals to humans is that some type of mutation occurred. Bacteria are, if anything, extremely industrious, and extremely adaptive. Like humans, their sole purpose is to survive and reproduce....only they do it much more effectively than we do, and more so, they do it exponentially faster than us. Sometimes bacteria mutates on its own because it is reproducing and thus mutating so rapidly, and at other times environmental conditions will play a big role.

If we look at the case of the tongue-eating isopod, which can now effect almost half a population of a certain fish (Snapper and Sea Bass have similar numbers), there are almost no reports of these isopods before the 1960s (right around the time when industrialization starts to really effect our water). And there were certainly no reports about isopods infecting fish in such large numbers. It would seem the isopods are reproducing at alarming rates, and have also mutated to enhance their survival. But what happens when they take over more fish? What if all fish begin to be infected from isopod prevalence and overfishing? They are going to run out of hosts, and will have to jump to new hosts.

Who has the closest contact to fish besides other fish?


Let?s take Bird Influenza, H5N1, as the nightmare scenario. Some people have caught H5N1 from cleaning or plucking infected birds. In China, there have been reports of infection via inhalation of aerosolized materials in live bird markets. It's also possible that some people were infected after swimming or bathing in water contaminated with the droppings of infected birds. And some infections have occurred in people who handle fighting cocks. People don't catch the virus from eating fully cooked chicken or eggs, but they can get it from eating raw infected chickens. There have even been a few cases where one infected person caught the bird flu virus from another person.

Then, as reported by WebMD, researchers from Erasmus Medical Center in the Netherlands made a stunning announcement in 2011. ?They had taught H5N1 the nasty trick of going airborne and spreading among ferrets. Why ferrets? Nearly all human flu bugs spread easily among ferrets. They are commonly used in studies of human flu viruses. In a statement, the NIH says the research shows "that the H5N1 virus has greater potential than previously believed to gain a dangerous capacity to be transmitted among mammals, including perhaps humans."

The studies remain extremely controversial, more so for moral reasons that scientific, who claim that the mutant virus should never have been created. But the point was they were created. The theory goes as follows: if a person -- or a susceptible animal -- gets infected with bird flu and human flu at the same time, the bird and human flu viruses could swap genes. Even without swapping genes, H5N1 could mutate into a form that more easily infects humans.

To say the least, it would be bad news if H5N1 were to become as contagious as human flu. If it remained as lethal as it is now, the fatality rate would be about 58%. The deadliest flu bug in history, which caused the 1918 Great Pandemic, had a fatality rate of 2%.

Could the tongue-eating isopod also mutate once it runs out of fish to occupy and move on to the species that has the closest contact with fish? Could fisherman who handle these creatures all the time one day become infected by them the same way those who handle and pluck infected chickens do? Could you be swimming in water with infected isopod feces and catch them the same way humans have caught bird flu? Or what about eating the wrong piece of raw fish? There are numerous parasites one always takes the risk of ingesting everytime he has a piece of raw fish, particularly fresh water fish like Salmon, which is the most consumer fish in the world. Or even worse, what if the microscopic isopod larvae gets into our drinking supply, and we ingest the isopod larvae directly?

Bird Flu jumps to mammals

My Take: Scary as they come. Shows that bird flu can jump to mammals in unexpected ways and in an even more deadly strain. Targets a protein in human lungs.


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A new flu virus identified in American harbour seals has the potential to pass to other mammals, including humans, experts say.

Former UVI professor names species for Bob Marley

My Take: Funny but alarming. Overfishing leads to hundreds of isopods in one fish.


A new species found in Virgin Islands waters has been named after Bob Marley by former University of the Virgin Islands professor Paul Sikkel.

Gnathia marleyi is a gnathiid isopod, a small parasitic crustacean that feeds off the blood of certain reef fish in the Caribbean the way a mosquito or tick feeds on mammals.

Secrets of Parasites' Replication Unraveled

My Take: Possible new weapon to fight parasitic disease. There is some hope.


A group of diseases that kill millions of people each year can't be touched by antibiotics, and some treatment is so harsh the patient can't survive it. They're caused by parasites, and for decades researchers have searched for a "magic bullet" to kill them without harming the patient. Now, a team of microbiologists at the University of Massachusetts Amherst has made an advance that could one day lead to a new weapon for fighting parasitic diseases such as African sleeping sickness, chagas disease and leishmaniasis.

Isopod Replaces Fish's Tongue

My Take: Isopod seen spreading to new geographical areas for first time.


The one-inch long isopod was found in a weaver fish's mouth by fishermen off the uninhabited Minquiers Islets (under the jurisdiction of Jersey, which is off the coast of Normandy, France). Marine isopods are crustaceans related to shrimps and crabs, and a number of species in the order Isopoda are parasitic. The Jersey specimen resembles a terrestrial louse. Among the fishermen was Paul Chambers, a marine scientist from the Soci?t? Jersiaise, who struggled to identify the specimen for several weeks before identifying the creature from a Victorian journal. Scientists from the University of Southampton confirmed the identification.

Parasites In Humans

My Take: Find the nastiest parasites in humans ? more worm based parasites but frightening none the less. Stool sample anyone?


Welcome to This website is all about parasitic infections caused by worms, microscopic protozoa and skin parasites. The worms category is divided into roundworms, flukes and tapeworms. You can find the parasites on the right navigational menu.

Each parasite species has two pages. The first of the two contains basic information such as: life cycle, symptoms, diagnosis and treatment. The second page has pictures and videos. If you do not have any specific parasite in mind, then start by reading below some basic information about parasitic diseases.